ISSN:0306-1353    

DOI:10.1039/AA98414FX001

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

SPECIALISTPERIODICALREPORTSA series of review volumespublished by the RSC whichprovide critical coverage ofmajor areas of research. Recentvolumes which may be ofinterest to analytical chemistsinclude:Electron SpinResonance Vo1.9A review of the literature publishedbetween December 1982 and May1984Hardcover 398pp 0 85186 831 2Mass SpectrometryVo1.7A review of the literature publishedbetween July 1980 and June 1982.Hardcover 439pp 0 85186 318 3Nuclear MagneticResonance Vol.14This volume reviews the literaturepublished between June 1983 andMay 1984.Hardcover 405pp 0 85186 372 Royal Society of ChemistryThe Chemical Analysis of WaterGeneral Principles and Techniques2nd Editionby D. T. E. Hunt and A. L. WilsonSince publication of the first edition of The Chemical Analysis of Water: General Principles andTechniques over 10 years ago, interest in water quality has continued to develop, and a num-ber of countries, including the United Kingdom, have developed new or extended existing legalrequirements on the qualities of various types of water.These requirements commonly call forthe measurement of many different substances, a large proportion of which must be measuredand controlled at very small concentrations. There have been considerable developments in theanalytical techniques and procedures applied to meet these needs, and semi- and fully-auto-matic procedures have been increasingly employed to meet the challenge of greater numbers ofsamples. Coupled with these changes has also been a much greater emphasis than before onthe importance of errors in analytical results, and on the need to estimate and control such er-rors. These developments have led to the need for a revised and updated edition of The Chemi-cal Analysis of Water.This second edition, like the first, attempts an integrated discussion of all aspects of themeasurement of water quality as a guide to those concerned with defining, establishing,controlling and reviewing programmes of water sampling and analysis.It provides a reasonablycomplete picture of the current state of the field for anyone wishing to become acquaintedwith it or any of its component aspects. The emphasis throughout is on fresh, natural watersand drinking waters although it is expected that much of the book will be found useful for othertypes of waters.In view of the above-mentioned emphasis on the errors of analytical results and the variousproblems that have been met in estimating and controlling the sizes of those errors, all parts ofthe text of the first edition that covered this subject have been greatly expanded.The bookprovides a comprehensive discussion of all types of error so that it may be used by analysts asan aid to ensuring the appropriate accuracy of analytical results. In addition, in response to themany developments in analytical techniques and procedures, many parts of the first editionthat dealt with these topics have been expanded and new sections have been added wherenecessary.Brief Contents:Introduction; Information Requirements of Measurement Programmes; Sampling; The Natureand Importance of Errors in Analytical Results; Estimation and Control of Bias of Analytical Re-sults; Estimation and Control of the Precision of Analytical Results; Achievement of SpecifiedAccuracy by a Group of Laboratories; Reporting Analytical Results; The Selection of AnalyticalMethods; General Precautions in Water-Analysis Laboratories; Glassware and Other Apparatus;Analytical Techniques; Computers in Water Analysis.Hardcover approx. 720pp ISBN 0 85186 797 9Further information about any ot these publications can be obtained from: Sales & PromotionDepartment, The Royal Society of Chemistry, krlington House, London WIV OB

ISSN:0306-1353    

DOI:10.1039/AA98414BX003

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

8 Analytical Atomic Spectroscopy 1.2 PLASMAS 1.2.1 I n d u c t i v e l y Coupled Plasmas It has been claimed t h a t t h e i n d u c t i v e l y coupled plasma occupies one o f t h e f a s t e s t growing sectors o f t h e a n a l y t i c a l instrument market. This reviewer would n o t dispute t h a t claim, having i n excess o f 300 r e p o r t s from j o u r n a l s and conferences t o assess.The l a r g e s t number by f a r deals w i t h aspects o f sampleAtomization and Excitation 9 i n t r o d u c t i o n , perhaps r e f l e c t i n g t h e attempts by a n a l y s t s t o e x p l o i t t h e sampling v e r s a t i l i t y o f t h e I C P . Amongst t h e most sought a f t e r improvements f o r r o u t i n e use i s g r e a t e r l o n g term s t a b i l i t y t o lessen t h e t i m e expended on c a l i b r a t i o n .The l i n k between s t a b i l i t y and sample i n t r o d u c t i o n , p a r t i c u l a r l y when a n e b u l i z e r i s used, g i v e s a f u r t h e r reason f o r t h e increased i n t e r e s t i n t h i s s u b j e c t . 1.2.1.1 Plasma C h a r a c t e r i s t i c s The e f f e c t i v e n e s s o f mathematical models i n p r e d i c t i n g plasma c h a r a c t e r i s t i c s i s l i m i t e d by t h e n e c e s s i t y t o make s i m p l i f y i n g assumptions t h a t a r e n o t i n accord w i t h experimental evidence.T h i s d i f f i c u l t y was acknowledged by Boulos e t a l . (C1094, C1351) who discussed m o d e l l i n g o f t h e s p a t i a l emission p a t t e r n from t h e ICP. A more e f f e c t i v e use o f m o d e l l i n g i s i n e l u c i d a t i n g sample t r a n s p o r t and v a p o r i z a t i o n mechanisms.E c k e r t (C1289). u s i n g p u b l i s h e d d a t a on plasma v e l o c i t i e s , i n t e g r a t e d ground-state atom and i o n p a r t i c l e d e n s i t i e s , and a p p r o x i m a t i n g e x c i t e d - s t a t e d e n s i t i e s by t h e assumption o f LTE, showed t h a t t h e t o t a l p a r t i c l e f l u x so c a l c u l a t e d i s t h e same as t h e i n j e c t e d p a r t i c l e f l u x if t h e n e b u l i z e r e f f i c i e n c y i s o f t h e o r d e r o f 17,.T h i s i s i n agreement w i t h p u b l i s h e d d a t a on a n a l y t e t r a n s p o r t e f f i c i e n c y .The v a p o r i z a t i o n o f i n d i v i d u a l s o l u t e p a r t i c l e s has been discussed by H i e f t j e e t a l . (C1352). They observed t h a t l a r g e r p a r t i c l e s vaporized w i t h a l i n e a r decrease i n t h e i r s u r f a c e area, whereas p a r t i c l e s w i t h diameters equal t o o r l e s s t h a n t h e gaseous mean f r e e p a t h v a p o r i z e w i t h a l i n e a r decrease i n t h e i r r a d i u s .It was p o s t u l a t e d t h a t t h i s was c o n s i s t e n t w i t h h e a t t r a n s f e r b e i n g t h e r a t e c o n t r o l l i n g process f o r t h e l a r g e r p a r t i c l e s and m o l e c u l a r release, as occurs i n vacuum evaporation, f o r t h e s m a l l e r (<4 urn) ones.Koirtyohann and Manning (C1118, C1967) used l a s e r s c a t t e r i n g t o m o n i t o r p a r t i c l e t r a j e c t o r i e s i n t h e plasma and found t h a t r e l a t i v e l y l i t t l e d e s o l v a t i o n occurred i n t h e i n j e c t o r tube, b u t t h a t t h e process was completed i n t h e pre-heating zone. It was suggested t h a t t h e t r a n s i t i o n from t h e i n i t i a l r a d i a t i o n zone t o t h e normal a n a l y t i c a l zone i s c o n t r o l l e d by t h e d e s o l v a t i o n r a t e .Some r e f r a c t o r y p a r t i c l e s a p p a r e n t l y passed t h r o u g h t h e plasma w i t h o u t complete v a p o r i z a t i o n . Plasma d i a g n o s t i c s t u d i e s r e q u i r e t h e a p p l i c a t i o n o f a range o f measurement techniques each p r o v i d i n g d i f f e r e n t p i e c e s o f data.Winefordner and Omenetto have pioneered t h e use o f l a s e r techniques f o r o b t a i n i n g s p a t i a l l y r e s o l v e d measurements o f plasma parameters and have now extended t h a t work t o s t u d y c o l l i s i o n a l energy exchange i n t h e plasma (6).Although fluorescence measurements p r o v i d e s p a t i a l l y r e s o l v e d i n f o r m a t i o n d i r e c t l y (C1097, C1513). a b s o r p t i o n spectrometry y i e l d s s p a t i a l l y i n t e g r a t e d data. T h i s l i m i t a t i o n can be overcome by u s i n g s a t u r a t e d a b s o r p t i o n spectroscopy (7, C275, C1590) i n which a high-powered l a s e r i s used t o "bleach" s e l e c t i v e l y t h e a b s o r p t i o n along10 Analytical Atomic Spectroscopy p a r t o f t h e p a t h and a second l a s e r , u s u a l l y a t r i g h t angles t o the f i r s t , i s used t o measure t h e l o c a l absorption o f t h e unbleached atoms.Determination o f f r e e - e l e c t r o n concentrations i s r e l a t i v e l y simple, b u t measurement o f t h e i r energy d i s t r i b u t i o n i s not.Thomson s c a t t e r i n g (C1130) i s a non-intrusive technique f o r free-electron energy measurement, b u t the s c a t t e r i n g cross-sections a r e so low t h a t high-power l a s e r s are necessary t o o b t a i n measurable l i g h t fluxes. The technique depends on determining t h e e l e c t r o n v e l o c i t i e s from t h e Doppler s h i f t s which broaden t h e probe beam s p e c t r a l l i n e .I n t e r f e r o m e t r i c high-resolution spectroscopy has many advantages i n diagnostics, f o r example i n temperature measurement ( C 361, 1819), o r f o r studying s p e c t r a l l i n e s h i f t s such as those induced by t h e Stark e f f e c t (1800).Mapping t h e s p e c t r a l emission from t h e whole plasma c e a r l y i n d i c a t e s t h e r e l a t i v e p o s i t i o n s and magnitudes o f t h e d i f f e r e n c e zones. blarshall e t a l . (C1591) accompl i shed t h i s by seeding t h e plasma flows w i t h Hg vapour whereas D i t t r i c h e t a l . (C1669, 2256) used the equidensitometry technique. A d d i t i o n a l references on t h e preceding t o p i c s - 650, C1660, 1697.The discussion o f e x c i t a t i o n mechanisms and p a r t i c l e d e n s i t i e s i n t h e I C P i s a popular t o p i c f o r conference presentations, b u t l e s s so f o r published papers where t h e onus o f p r o o f i s greater. Various models have been proposed, each g i v i n g weight t o d i f f e r e n t aspects and addressing p a r t i c u l a r problems, notably: r e a c t i o n r a t e models, t h e i o n i z i n g and recombining plasma models, and those t h a t emphasize t h e r o l e o f p a r t i c u l a r processes such as resonant charge t r a n s f e r , Penning i o n i z a t i o n / e x c i t a t i o n , r a d i a t i o n t r a p p i n g and ambipolar d i f f u s i o n .De Galan (311) has suggested t h a t the various mechanisms a r e complementary and t h a t t h e plasma should be viewed as decaying from conditions o f heterogeneous e q u i l i b r i u m t o homogeneous thermal e q u i l i b r i u m . H i e f t j e and co-workers (C1356, C1943) have continued t h e i r i n v e s t i g a t i o n s i n t o t h e importance o f t h e metastable and low-lying r a d i a t i v e s t a t e s o f A r i n c o n t r o l l i n g t h e e x c i t a t i o n processes and energy t r a n s p o r t w i t h i n t h e plasma.They reported (1777) a r a d i a t i o n t r a p p i n g l i f e t i m e o f 1.6 ps which a t a plasma v e l o c i t y o f 30 m s-l would support t h e plasma o n l y 0.05 mm beyond t h e energy a d d i t i o n zone.It was concluded t h e r e f o r e t h a t o t h e r mechanisms o f plasma maintenance must be sought. Haraguchi (C1350) found A r metastable population d e n s i t i e s o f 2 x lo1’ compared w i t h an e q u i l i b r i u m value o f 5 x 1015 (assuming Texc = 7000 K and ne = 5 x l O I 5 ~ m - ~ ) . These data were considered t o be i n accordance w i t h t h e recombining plasma model discussed by Boumans (ARAAS, 1982, - 12, Ref. 1376). H o r l i c k and G i l l s o n (C1355) found t h a t f o r Ca 90% was i o n i z e d even a t powers down t o 0.5 kW. Concurrent emission measurements showed t h a t a t low powers, although i o n d e n s i t i e s are high, i o n i c emission i s low o r non-existent. This was considered t o i n d i c a t e a two-stage e x c i t a t i o n process which Mermet and Goldwasser (C1357) i s against t h e t r e n d o f c u r r e n t t h i n k i n g .Atomization and Excitation 1 1 have again commented on t h e strong experimental evidence f o r t h e dominance o f t h e resonant charge t r a n s f e r e x c i t a t i o n mechanism.A d d i t i o n a l references on t h e preceding t o p i c s - C121, 156, 560, C1301.It i s n o t p o s s i b l e t o separate a discussion o f e x c i t a t i o n mechanisms from t h e s p a t i a l c h a r a c t e r i s t i c s o f t h e I C P t h a t are derived from them. The heterogeneity o f the plasma has been studied by Rayson e t a l . (C1096) who compared s p a t i a l maps o f h y p o t h e t i c a l plasma reactions w i t h those obtained by d i r e c t observation.Houk and Olivares (315) proposed a simple model f o r v e r t i c a l emission p r o f i l e s i n the I C P based on LTE, b u t i n which t h e degree o f i o n i z a t i o n v a r i e s w i t h h e i g h t i n a manner t h a t i s independent o f temperature. This approach c o r r e c t l y p r e d i c t s t h e i n v a r i a n c e o f emission peak w i t h element f o r i o n l i n e s , i n d i c a t e s s i m i l a r behav l i n e s having e x c i t e d s t a t e s above 5 eV, and shows t h a t atomic e x c i t a t i o n energy peak lower i n the plasma.I n contrast, Horl t h e e x c i t a t i o n the v e r t i c a l our f o r atomic l i n e s o f lower ck and Choot (C1358, C1900) demonstrated t h a t f o r both A r and A r / N 2 plasmas, peak emission i n t e n s i t i e s c o r r e l a t e d c l o s e l y w i t h e l e c t r o n density.A s p a t i a l study o f departures from LTE i n t h e c e n t r a l channel by Blades and Caughlin (C1354) i n d i c a t e d t h a t throughout the plasma, t h e ground-state i s over-populated w i t h respect t o LTE, i n d i c a t i n g an i o n i z i n g plasma. The mechanism o f i n t e r f e r e n c e by e a s i l y i o n i z a b l e elements remains p o o r l y understood, b u t t h i s year two groups have studied t h e problem and there i s a measure o f agreement between t h e i r f i n d i n g s .Zeeman and Gunter (C272, C274) studied Ca ground-state and excited-level populations f o r both atoms and i o n s and found t h a t t h e presence o f an i n t e r f e r a n t increased i o n i c and atomic e x c i t e d s t a t e populations w h i l s t producing a decrease i n both i o n i c ground-state populations and unchanged atomic ground-state populations.This was explained by assuming t h a t ambipolar d i f f u s i o n p l a y s an important r o l e i n t h e t r a n s f e r o f energy from the core t o t h e c e n t r a l channel, and t h a t t h e i n t e r f e r a n t produces enhanced r a t e s o f c o l l i s i o n a l e x c i t a t i o n and recombination.Previous r e p o r t s have shown t h a t e l e c t r o n concentrations i n t h e b u l k o f t h e plasma gas remain l a r g e l y unchanged i n t h e presence o f e a s i l y i o n i z a b l e elements, b u t Koirtyohann and P r e l l (C1157, C1966) claimed t h a t l o c a l increases i n e l e c t r o n concentrations do occur i n the c e n t r a l channel and t h a t t h e observed i n t e r f e r e n c e s c o r r e l a t e w e l l w i t h data on e l e c t r o n e x c i t a t i o n cross-sections.They support t h e conclusion t h a t ambipolar d i f f u s i o n i s a key process i n t h e t r a n s f e r o f energy from t h e plasma core t o t h e c e n t r a l channel.Molecular gas and molecular gas-cooled plasmas a r e l e s s expensive t o operate and have p o t e n t i a l l y b e t t e r sample decomposition p r o p e r t i e s than a l l A r plasmas. The 0 plasma decomposes r e f r a c t o r y oxides b e t t e r than e i t h e r A r o r N2 plasmas (C1095) and l i k e t h e 02-coo1ed plasma, e x h i b i t s a much cleaner background spectrum than does the N2-coo1ed plasma (C1359, 1892).Goldfarb and 21 2 Analytical Atomic Spectroscopy Goldfarb (C1331) reported t h e use o f an Ar-cooled I C P f o r f l u e gas analysis and demonstrated t h a t t h e molecular a d d i t i v e s influenced atomic l i n e i n t e n s i t i e s f o r C, ti, N and 0.A d d i t i o n a l reference on t h e preceding t o p i c - C2472. The accumulation and t a b u l a t i o n o f spectral data from t h e I C P i s an extremely laborious process and analysts w i l l be g r a t e f u l t o those workers who have undertaken t h i s task. Notably t h i s year, Anderson and Parsons (595, 1828) have published d e t a i l e d spectra f o r t h e Group I I I A elements and have used these data t o assess i n t e r f e r e n c e e f f e c t s on 71 elements commonly determined by ICP-OES.I n t e r f e r e n c e s from Group I I A elements are a l s o included. Wittmann (675) has l i s t e d l i n e s f o r 40 elements, commonly determined i n steels, t h a t are n o t prone t o i n t e r f e r e n c e from a m a t r i x containing 5000 ug m l - 1 Fe.S i m i l a r l y , f o r geological materials, an a t l a s o f l i n e s and i n t e r f e r e n c e s has been compiled by Brenner and Eldad (C1589). The vacuum u l t r a v i o l e t region o f the spectrum (85 - 200 nm) has been studied by two groups (314, C1360, C1583) who reported t h a t t h e p r i n c i p a l emissions observed were from A r , C, H, N and 0.The importance o f t h e A r resonance l i n e s a t 104.82 and 106.67 nm i n studying plasma mechanisms was noted, as was t h e absence o f emissions from A r t o r A r 2 which are both observed i n ICP-MS mesurements. I n the more accessible p a r t o f t h e V.U.V. t h e r e are u s e f u l l i n e s f o r t h e non-metals such as C, I , P and S (C89, C1582, C2426).and Fuwa - a l . (1848) reported a d e t e c t i o n l i m i t o f l e s s than 1 ng m1-l f o r A1 using t h e 167.079 nm l i n e . Spectral l i n e s f o r t h e determination o f B r (1785) and Br, C1 and I (679, 726) have been l i s t e d , and i n one r e p o r t a reduced pressure I C P run on He was described (C1111). Other references o f i n t e r e s t - A x i a l l y viewed plasma: C2483.Determination o f t r a n s i t i o n p r o b a b i l i t i e s o f A r i n t h e I C P ; C276. New s p e c t r a l i n t e n s i t y formula: C1100, C1153. 1.2.1.2 Sample I n t r o d u c t i o n Browner (951, 952) has described sample i n t r o d u c t i o n as t h e A c h i l l e s ' heel of atomic spectrometry. This d e s c r i p t i o n most a p t l y applies t o nebulizers and spray chambers and t h i s year considerable e f f o r t has been devoted t o t h e design and c h a r a c t e r i z a t i o n o f these devices.Most c o n t r o v e r s i a l has been t h e method by which t h e e f f i c i e n c y should be determined. It i s t h e reviewer's o p i n i o n t h a t t h i s debate i s being pursued on t h e wrong ground. Most authors now accept t h a t t h e d i f f e r e n t methods determine d i f f e r e n t q u a n t i t i e s and t h e r e f o r e t h e question t o be addressed i s what do we wish t o measure, n o t which method should be used. From t h e measurement standpoint, t h e q u a n t i t y t h a t i s most e a s i l y understood and i s unassailable i n terms o f i t s d e f i n i t i o n i s t h e analyteAtomization and Excitation 13 t r a n s p o r t e f f i c i e n c y .I t so happens t h a t t h e s i m p l e d i r e c t f i l t e r method t h a t b e s t e s t i m a t e s t h i s q u a n t i t y i s a l s o t h e l e a s t s u b j e c t t o e r r o r . Browner and co-workers (1951 ) have t h e r e f o r e s t r o n g l y advocated t h i s procedure.Other workers (309, C1288, 1950, 1980) have p r e f e r r e d i n d i r e c t methods o f e f f i c i e n c y measurement, which though s u b j e c t t o g r e a t e r s t a t i s t i c a l e r r o r , do g i v e an i n d i c a t i o n o f t h e t o t a l s o l v e n t t r a n s p o r t e f f i c i e n c y . Aerosol and vapour load- i n g markedly a f f e c t plasma performance (C1285) and t h e r e f o r e u l t i m a t e l y b o t h t h e a n a l y t e t r a n s p o r t e f f i c i e n c y and t h e complete phase composition o f t h e a e r o s o l a r e r e q u i r e d .Perhaps a combination o f techniques, i n c l u d i n g t h e s i l i c a - g e l t r a p method as proposed by de Galan (MAAS, 1983, 13, Ref. 350) w i l l p r o v i d e t h e most u s e f u l data.T h e o r e t i c a l and m o d e l l i n g s t u d i e s on n e b u l i z e r s p r o v i d e i n s i g h t s i n t o t h e i r mechanism and o p e r a t i o n and should lead t o improvements i n design. Un- f o r t u n a t e l y , no s i g n i f i c a n t advances have y e t been d e r i v e d from t h i s endeavour. Cresser e t a l .(1864, 1866, C2427; see a l s o S e c t i o n 1.3.3.1) s t u d i e d n e b u l i z e r s u c t i o n and noted i t s v a r i a t i o n w i t h uptake r a t e u s i n g a T-piece manometer connected t o t h e a s p i r a t i o n c a p i l l a r y . They demonstrated t h a t observed temperature e f f e c t s i n AAS c o r r e l a t e d w i t h changes i n t h e s u c t i o n and t h a t t h e l a t t e r can be used t o p r o v i d e s i g n a l compensation.The Nukiyama-Tanasawa e q u a t i o n i s o f t e n quoted i n attempts t o e x p l a i n t h e e f f e c t s o f t h e p h y s i c a l p r o p e r t i e s o f t h e s o l u t i o n on n e b u l i z a t i o n (C1114, 1808). Q u a l i t a t i v e l y , t h e r e i s reasonable agreement, b u t t h e r e i s no p r o o f t h a t t h e e q u a t i o n a p p l i e s s t r i c t l y t o a n a l y t i c a l n e b u l i z e r s .Gustavsson (C1113) has c o n t i n u e d h i s work on t h e m o d e l l i n g o f n e b u l i z e r s and spray chambers, and Browner's group have r e p o r t e d s t u d i e s on d r o p l e t s i z e (C1151), aerosol composition (C1116). and i n t e r f a c i n g F I and HPLC t o ICP-OES (C1217).A d d i t i o n a l r e f e r e n c e on t h e preceding t o p i c - C1517. Comparisons and o p t i m i z a t i o n s o f n e b u l i z e r s have been r e p o r t e d by s e v e r a l groups. Sharp e t a l . (C1287) presented a d e t a i l e d p a r a m e t r i c design s t u d y o f t h e cross-flow n e b u l i z e r , u s i n g l a s e r p a r t i c l e s i z i n g t o c h a r a c t e r i z e t h e aerosol.F a c t o r s s t u d i e d were t h e e f f e c t o f pressure, gas f l o w o r i f i c e area, l i q u i d c a p i l l a r y t u b e diameter, uptake r a t e and r e l a t i v e alignment o f t h e gas j e t and l i q u i d c a p i l l a r y . It was shown t h a t t h e performance was p r i n c i p a l l y determined by t h e l i q u i d - t o - g a s r a t i o , r e g a r d l e s s o f t h e means used t o achieve it, and t h e r e l a t i v e alignment.S i m i l a r c o n c l u s i o n s were reached i n a s t u d y by F u j i s h i r o e t a l . (321). Meinhard (C1286) has attempted t o c l a s s i f y s t r u c t u r a l d e t a i l s as t h e y a f f e c t performance and has shown t h a t r e c e s s e d - t i p c o n c e n t r i c n e b u l i z e r s a r e l e s s prone t o s a l t i n g - u p than a r e t h o s e h a v i n g a f l u s h t i p (2211).A comparison o f aerosol s i z e d i s t r i b u t i o n s f o r v a r i o u s c o n c e n t r i c n e b u l i z e r s (C1145), and a V-groove n e b u l i z e r coupled t o d i f f e r e n t spray chambers showed as expected t h a t t h e spray chamber p r i n c i p a l l y determines t h e n a t u r e o f14 Analytical Atomic Spectroscopy t h e aerosol reaching t h e plasma. For t h e spray chamber studied, t h e l a r g e s t d r o p l e t s reaching t h e plasma were 12 urn i n diameter.Several groups have compared n e b u l i z e r s through t h e i r a n a l y t i c a l performance.This i s t h e u l t i m a t e t e s t , b u t g r e a t care i s needed i n i n t e r p r e t i n g the r e s u l t s because even though t h e comparisons may be made on one system, t h e operating c o n d i t i o n s f o r t h a t system may be c l o s e r t o optimum f o r a p a r t i c u l a r n e b u l i z e r than they are f o r another. Maessen e t a l .(328) c a r r i e d o u t a comprehensive study o f 5 nebulizers, two concentric, a f i x e d and an a d j u s t a b l e cross-flow, and a V-groove. i n terms o f t h e SBR r a t i o f o r a mixed group o f "hard" and ' ' s o f t ' ' l i n e s . The f o l l o w i n g conclusions were drawn: pump feeding reduces t h e s e n s i t i v e dependence o f SBR on the applied pressure: l i n e s d i v i d e i n t o "hard" and " s o f t " categories w i t h o n l y small d i f f e r e n c e s i n the optimum a p p l i e d pressure between t h e two groups; no n e b u l i z e r produced t h e highest SBR f o r a l l 14 l i n e s studied: t h e SBRs g e n e r a l l y d i f f e r e d by l e s s than one order o f magnitude between nebulizers. I n addition, i t was shown t h a t t h e product o f t h e e f f i c i e n c y and t h e l i q u i d uptake r a t e v a r i e s i n such a way as t o keep t h e analyte mass f l u x t o t h e plasma r e l a t i v e l y constant: thus t h e gas f l o w r a t e was c i t e d as t h e most important independent variable. S i m i l a r comparative s t u d i e s have been t h e subject o f conference r e p o r t s (C1291, C1610, C1930), and Mernet i n p a r t i c u l a r (C1451) compared t h e performance o f concentric, cross-flow, V-groove, u l t r a s o n i c and frit nebulizers operating below 0.7 1 min-I.It was concluded t h a t t h e u l t r a s o n i c n e b u l i z e r provided t h e best r e s u l t s , b u t l i k e the f r i t n e b u l i z e r has operational disadvantages. The V-groove n e b u l i z e r was t h e best compromise, b u t c u r r e n t designs r e q u i r e a higher s o l u t i o n throughput than o t h e r types and t h e r e f o r e t h e e f f i c i e n c y i s poor.A d d i t i o n a l reference on t h e preceding t o p i c - C1915. R a d i c a l l y new n e b u l i z e r designs are r a r e , b u t t h i s year d e t a i l e d d e s c r i p t i o n s o f devices p r e v i o u s l y reported a t conferences have been published.Thus Doherty and H i e f t j e (1008) described t h e i r j e t impaction n e b u l i z e r (see ARAAS, 1982, 12, Ref. C1335). To r e s t r i c t f l o w r a t e s t o acceptable l e v e l s , an o r i f i c e diameter o f 60 urn i s necessary which l i m i t s t h e device t o use w i t h p a r t i c l e - f r e e solutions.S i m i l a r l y , Lawrence e t a l . (564) have published d e t a i l s o f t h e i r micro-concentric n e b u l i z e r (see ARAAS, 1983, 13, Ref. C2151) f o r i n t e r f a c i n g F I o r HPLC t o t h e I C P . Automatic devices f o r micro-sample i n t r o d u c t i o n t o nebulizers have been described by Sobel (1826) and by Z i l ' b e r s h t e i n e t a l .(1283) and t h e r e have been f u r t h e r r e p o r t s o f t h e use o f r e - c i r c u l a t i n g n e b u l i z e r s (C1290, C2475) f o r small volume samples. E l e c t r o s t a t i c techniques o f spray generation have been reviewed by B a i l e y (1409). The i n t r o d u c t i o n o f t h e V-groove n e b u l i z e r has l e d t o i n c r e a s i n g use o f s l u r r y n e b u l i z a t i o n (see Section 3.1.3.1).T h i s procedure avoids timeAtomization and Excitation 15 consuming d i s s o l u t i o n procedures, b u t as demonstrated by Ebdon and Gray (C2477). atomization e f f i c i e n c i e s a r e o f t e n low (x 50%) and t h e r e f o r e t h e technique i s most s u i t e d t o determinations i n matrices o f constant major element composition, e .~ . , Ti02 (C1133; see ARAAS, 1982, 3. Ref. 1293) and t o those where t h e p a r t i c l e s i z e can be w e l l c o n t r o l l e d and reduced t o 10 yn o r l e s s (C1489). Clays are an obvious candidate f o r s l u r r y n e b u l i z a t i o n and these were studied by Spier e t a l . (193) who a t t r i b u t e d t h e r e l a t i v e l o s s i n signal, i n comparison t o aqueous standards, t o reduced sample t r a n s p o r t e f f i c i e n c y .Watson and Ploore (2397) combined pre-concentration and s l u r r y atomization by adsorbing noble metals onto an anion-exchange r e s i n and then d i r e c t l y n e b u l i z i n g t h e r e s i n beads i n t o t h e plasma. A d d i t i o n a l references on t h e preceding t o p i c - C1437, C1439, C1969, C2459.The u l t r a s o n i c (2287) and frit nebulizers are t h e o n l y types t h a t o f f e r s i g n i f i c a n t improvements i n e f f i c i e n c y , b u t both s u f f e r from operational and r e l i a b i l i t y problems, l a r g e l y r e l a t e d t o memory e f f e c t s and sample changeover. There have been r e p o r t s t h i s year o f t h e i r use w i t h organic solvents (659, C1399) t h a t e x p l o i t t h e i r a b i l i t y t o run a t low solvent and gas flow-rates.The f r i t n e b u l i z e r (C1119, C1400) has been employed f o r coupling micro-bore HPLC t o t h e ICP. The a p p l i c a t i o n o f an u l t r a s o n i c n e b u l i z e r w i t h a commercially a v a i l a b l e ICP-AFS instrument was described by Lancione and Drew (C1074) The use o f organic solvents r e q u i r e s d i f f e r e n t plasma operating c o n d i t i o n s t o those used f o r aqueous samples.Several groups (248, C349, C1216, 2117) have discussed operating c o n d i t i o n s appropriate t o verious solvents and determinations. The most s i g n i f i c a n t c o n t r i b u t i o n came from Pllaessen and co-workers (2252) who demonstrated t h a t c o o l i n g and t h e r m o s t a t t i n g o f the spray chamber can be used t o c o n t r o l and optimize s o l v e n t loading of the plasma when using v o l a t i l e materials.Spray chambers perform t h e c r u c i a l f u n c t i o n of c o n d i t i o n i n g t h e aerosol produced by t h e n e b u l i z e r t o render i t s u i t a b l e f o r i n t r o d u c t i o n i n t o t h e plasma.They remain. however, p o o r l y understood and the complexity o f t h e processes t a k i n g place i m p l i e s t h a t modelling t h e i r behaviour w i l l not be easy. Gustavsson ( 8 ) has reviewed some o f t h e basic ideas r e l a t i n g t o i n e r t i a l impaction and has proposed c y c l o n i c a c t i o n and j e t impaction as u s e f u l concepts f o r chamber design.U n f o r t u n a t e l y these i d e a l i z e d systems do not take f u l l cognisance o f t h e p r a c t i c a l aspects o f n e b u l i z e r operation. A sample modulation system, based on a motorized p i s t o n i n s e r t e d i n t o t h e spray chamber, was described by Steele and H i e f t j e (C1129).Haapakka and Stephens (1787) reported the coupling of an e l e c t r o s t a t i c aerosol c o l l e c t i o n device (see ARAAS, 1932, 2, Ref. 1901) t o a low-powered r.f. plasma (30 W a t 2 MHz) and Schutyser and Janssens (307) have again stressed the importance o f good drainage i n avoiding noise on t h e o p t i c a l signal. Desolvation systems a r e not widely used,16 Analytical A tomic Spectroscopy b u t Marinov (872, 2012, 2282) employed a d e s o l v a t i o n system t o enhance s e n s i t - i v i t i e s f o r t r a c e elements i n b i o l o g i c a l f l u i d s .Enhancements i n sample t r a n s p o r t due t o t h e presence o f v o l a t i l e M o ( C O ) ~ i n n e b u l i z e d o r g a n i c s o l v e n t s were observed by Sanz-Medel and Sanchez-Uria (C2466).b u t Coleman (2118) commented on t h e e x c e p t i o n a l l y l o n g sample clean-out t i m e s t h a t were r e q u i r e d when Hg was determined i n o r g a n i c solvents. A s u r f a c e c o a t i n g t h a t i s r e s i s t a n t t o HF b u t h y d r o p h i l i c (an a l k a l i - m e t a l aromatic complex) was used t o t r e a t a spray chamber p r i o r t o t h e a n a l y s i s o f HF d i g e s t s o f b o r o s i l i c a t e g l a s s (2553).Flow i n j e c t i o n (see a l s o S e c t i o n 3.1.3.2) i s now used w i t h a wide range o f a n a l y t i c a l d e t e c t i o n systems. Sample throughput, ease o f chemical m a n i p u l a t i o n , and s t a n d a r d i z a t i o n and a b i l i t y t o overcome some o f t h e d i f f i c u l t i e s a s s o c i a t e d w i t h n e b u l i z a t i o n a r e i t s d e s i r a b l e p r o p e r t i e s .Thus, I s r a e l 1 and Sarnes (775) d e s c r i b e d an implementation o f t h e standard a d d i t i o n s method and demonstrated i t s a p p l i c a b i l i t y t o t h e d e t e r m i n a t i o n of S i i n phosphoric a c i d .The same group (C1294) r e p o r t e d a combination of F I and h y d r i d e g e n e r a t i o n f o r t h e d e t e r m i n a t i o n o f As i n g l y c e r i n e a t t h e 0.5 - 7.0 ug g l e v e l . McLeod e t a l . (C1378) used F I i n combination w i t h ion-exchange s e p a r a t i o n f o r t h e d e t e r m i n a t i o n o f P i n s t e e l .An automatic i n j e c t i o n and d i l u t i o n system (termed AIDS), based on FI p r i n c i p l e s , f o r t h e a n a l y s i s of o i l samples was d e s c r i b e d by Evans and Klueppel (C1330). The a u t h o r s commented t h a t w i t h AIDS, an a n a l y s t can a c c u r a t e l y detemine up t o 60 elements s i m u l t a n e o u s l y a t a r a t e o f 80 samples p e r hour.Imagine what he m i g h t accomplish i f he were f i t ! d i l u t i o n -1 Thermal v o l a t i l i z a t i o n o f samples i n t o t h e plasma encompasses by f a r t h e l a r g e s t s i n g l e group o f p u b l i c a t i o n s on t h e I C P t h i s y e a r (see a l s o S e c t i o n 3.1.7). There a r e two b a s i c techniques, d i r e c t i n s e r t i o n o f a g r a p h i t e probe o r i n d i r e c t v a p o r i z a t i o n by an e l e c t r o t h e r m a l atomizer.U n f o r t u n a t e l y , as y e t t h e r e has n o t been a d i r e c t comparison o f t h e two approaches assessing t h e i r r e l a t i v e m e r i t s , a l t h o u g h t h e probe technique has obvious advantages f o r d i r e c t s o l i d s a n a l y s i s .Conventional I C P systems a r e n o t designed t o handle t r a n s i e n t s i g n a l s and r e q u i r e m o d i f i c a t i o n (C1218, C1970). Broekaert and Laqua (C352) discussed peak h e i g h t , peak area measurement and i n t e r n a l s t a n d a r d i z a t i o n i n r e l a t i o n t o i m p r o v i n g t h e p r e c i s i o n o f d e t e r m i n a t i o n and d e s c r i b e d t h e use o f a dual channel monochromator and a SIT-vidicon f o r simultaneous l i n e and background measurement.The e l e c t r o t h e r m a l atomizers c u r r e n t l y i n use a r e l a r g e l y a d a p t a t i o n s o f those designed f o r AAS (475, 904, 1822, 2616), b u t H u l l and H o r l i c k (1822) commented t h a t purpose b u i l t atomizers should p r o v i d e improved performance.Matusiewicz and Barnes (C1296, 1767) employed t h e a e r o s o l deposition-ETA technique f o r sample i n t r o d u c t i o n , whereas H i e f t j e e t a l . (C1128, C1534) went a s t a g e f u r t h e r , d e s c r i b i n g a c o n t i n u o u s l y operated g r a p h i t eAtomization and Excitation 17 f u r n a c e It was suggested t h a t t h i s d e v i c e m i g h t be u s e f u l i n c o n j u n c t i o n w i t h F I o r LC.M e t a l f i l a m e n t v a p o r i z e r s o f f e r h i g h e r h e a t i n g r a t e s and p r o b a b l y l e s s p e r t u r b a t i o n o f t h e i n j e c t o r gas temperature t h a n do carbon-furnace types. Tikkanen and Miemcizyk (1760) d e s c r i b e d a Ta b o a t v a p o r i z e r t h a t c o u l d be r a p i d l y interchanged w i t h t h e spray chamber and Takahashi e t a l .(C1956) made use o f a W-filament v a p o r i z e r . Bulk o r powdered metal samples were v a p o r i z e d i n t o an ICP by i n d u c t i o n h e a t i n g i n a r e f r a c t o r y c r u c i b l e (487). o n t o which l i q u i d was f e d a t a r a t e o f 20 u l min-l. No concensus has y e t emerged on t h e b e s t design o f d i r e c t plasma i n s e r t i o n devices.K i r k b r i g h t ' s group (771, C1490, C2473) compared f o u r g r a p h i t e cup d e v i c e s and found t h a t r e d u c t i o n o f t h e s u p p o r t r o d diameter improved h e a t i n g r a t e s and peak h e i g h t s e n s i t i v i t i e s .Glassy carbon was found t o improve s i g n i f i c a n t l y t h e s e n s i t i v i t y f o r N i . There have been a number o f a p p l i c a t i o n s papers (1796, C1968, 2246, 2249). b u t most a r e c o n f i n e d t o r e p o r t i n g t h e o p t i m i z a t i o n o f c o n d i t i o n s and a n a l y s i n g CRMs. Salim and Habib (773, C1298, C1438. C1989) used c a t h o d i c r e d u c t i o n o n t o an Hg coated carbon e l e c t r o d e as a p r e - c o n c e n t r a t i o n technique.F o l l o w i n g d r y i n g , t h e e l e c t r o d e was i n s e r t e d d i r e c t l y i n t o an ICP and t h e d e p o s i t e d c a t i o n s determined by OES. A t w e n t y - f o l d improvement i n s e n s i t i v i t y , compared w i t h n e b u l i z a t i o n , was achieved and t h e RSD was 3%.Z i l ' b e r s h t e i n e t a l . (C1594) r e p o r t e d t h a t i t was p o s s i b l e t o analyse some non-conducting m a t e r i a l s , *, q u a r t z , by d i r e c t s i d e - i n s e r t i o n o f t h i n sample r o d s i n t o t h e plasma. The use o f spark e r o s i o n as a means o f i n t r o d u c i n g c o n d u c t i n g s o l i d s and powder i n t o t h e ICP i s growing, w i t h a t l e a s t two manufacturers r e p o r t i n g a n a l y t i c a l a p p l i c a t i o n s (C1115, C1441, C1584, C1971, C1936, 2344).A z i z e t a l . (C1297, 2245) s t u d i e d o p t i m a l spark c o n d i t i o n s f o r t h e a n a l y s i s o f aluminium a l l o y s . A medium v o l t a g e (1 kV) spark a t a r e p e t i t i o n r a t e o f 25 Hz gave t h e b e s t r e s u l t s , b u t i t was found t h a t t h e mass f l u x t o t h e plasma was low and s e n s i t i v i t i e s c o r r e s p o n d i n g l y poor.A h i g h e r v o l t a g e spark eroded more sample, b u t o f a l a r g e r p a r t i c l e s i z e . It was subsequently found t h a t by i n c r e a s i n g t h e spark r a t e t o 400 Hz.d e t e c t i o n l i m i t s c o u l d be improved by an o r d e r of magnitude. Takahashi e t a l . (857) employed an aerosol c y c l o n e t o separate t h e l a r g e and f i n e p a r t i c l e s produced by low-voltage spark sampling o f a l l o y - s t e e l s . D i r e c t c u r r e n t a r c s (see a l s o S e c t i o n 3.1.3.1) can a l s o be used f o r s o l i d sampling (488).Page e t a l . (312) used t h e c a r r i e r d i s t i l l a t i o n technique, employing S c r i b n e r - M u l l i n e l e c t r o d e s covered w i t h a g r a p h i t e l i d h a v i n g a c e n t r a l hole, f o r t h e a n a l y s i s o f uranium oxide. A d d i t i o n a l r e f e r e n c e s on t h e p r e c e d i n g t o p i c - C1082, C1137, 2319.Laser a b l a t i o n p r o v i d e s a means o f sampling non-conducting m a t e r i a l s and can be used f o r micro-samples. Thompson and Hale (2530) analysed heavy m i n e r a l g r a i n s from stream sediments s e t i n t o a p o l y t h e n e h o l d e r w i t h p o l y s t y r e n e18 Analytical Atomic Spectroscopy cement. C a l i b r a t i o n was achieved by e s t a b l i s h i n g s e n s i t i v i t y r a t i o s using conventional n e b u l i z a t i o n and v a l i d a t i o n w i t h grains o f known composition.I n a f u r t h e r paper from t h e same group (2365), Fe and Mn oxide coatings on stream pebbles were analysed. Russo (C1183) studied t h e fundamental aspects o f t h e l a s e r - s o l i d i n t e r a c t i o n and found t h a t w i t h r e p e t i t i v e p u l s i n g o f t h e l a s e r , t h e emission a t f i r s t increased, b u t a f t e r a t t a i n i n g a maximum, s e t t l e d t o an e q u i l i b r i u m l e v e l .By measuring o n l y a f t e r e q u i l i b r i u m was reached, plasma c o n d i t i o n s could be more r e a d i l y optimized, and improved p r e c i s i o n was obtained. A d d i t i o n a l reference on t h e preceding t o p i c - 972.Other references o f i n t e r e s t - Chemical vapour generation: C2461. D i r e c t i n j e c t i o n o f powders i n t o an I C P : 721, C1440. 1.2.1.3 Optimization, C a l i b r a t i o n and I n t e r f e r e n c e s There i s a considerable expenditure o f e f f o r t on o p t i m i z a t i o n of plasma c o n d i t i o n s and r e p o r t s o f these endeavours occur r e g u l a r l y i n t h e l i t e r a t u r e .Unfortunately, very few o f t h e f i n d i n g s are d i r e c t l y t r a n s f e r r a b l e and t h i s s i t u a t i o n w i l l p e r s i s t unless t h e r e i s a move towards s t a n d a r d i z a t i o n o f the hardware. The mechanics o f using t h e Simplex o p t i m i z a t i o n technique are r e l a t i v e l y simple and t h e most d i f f i c u l t aspect i s choosing a s u i t a b l e o b j e c t i v e variable.Lukasiewicz and Dewalt (C1346) compared SBR and d e t e c t i o n l i m i t as t h e o b j e c t i v e v a r i a b l e and claimed t h a t t h e former tended t o produce low background conditions, by reducing t h e power, and correspondingly low analyte emission l e v e l s , Using t h e d e t e c t i o n l i m i t , a compromise between net s i g n a l i n t e n s i t y and SBR was obtained t h a t was reported t o provide b e t t e r powers o f detection.Moore e t a l . (1782) a p p l i e d the Simplex technique t o a N -cooled plasma by s e q u e n t i a l l y o p t i m i z i n g f o r maximum SBR and then minimum i n t e r f e r e n c e from e a s i l y i o n i z a b l e elements.Compromise c o n d i t i o n s were thus established t h a t s a t i s f i e d both objectives. Kosman e t a l . (C1401) used t h e Simplex method t o optimize an LC-ICP system f o r t h e determination o f Fe, N i , P, V and Zn, b u t found t h a t each element r e q u i r e d s i g n i f i c a n t l y d i f f e r e n t conditions.Attempts t o d e f i n e a s i n g l e o b j e c t i v e v a r i a b l e f o r t h e simultaneous o p t i m i z a t i o n of such a group o f elements leads t o poor convergence o f t h e algorithm. Many workers p e r s i s t w i t h t h e u n i v a r i a t e search which i n general does n o t l o c a t e t h e optimum p o i n t i n f a c t o r space.I t does, however, map the f a c t o r space and computerization o f t h e procedure can produce considerable savings i n time (955). 2 A d d i t i o n a l reference on t h e preceding t o p i c - C2464. Accurate c a l i b r a t i o n i s a prime determinant i n the q u a l i t y o f a n a l y t i c a l data and t h e method selected should take account o f t h e known sources of e r r o r t o which a technique i s subject.Bubert and Klockenkaemper (164) have again stressed t h e need f o r appropriate weighting i n l e a s t squares f i t t i n g t oAtomization and Excitation 19 compensate f o r v a r i a b l e p r e c i s i o n over t h e c a l i b r a t i o n range (see ARAAS, 1982, - 12, Refs. 549, 1374). The u t i l i t y o f e s t a b l i s h i n g i n t e r n a l plasma reference points, by monitoring atom/ion l i n e r a t i o s (see ARAAS; 1982, 3, Ref. 1794) has been f u r t h e r advocated by Anderson e t a l . (313). Two groups (C1318, C1381) have I n t h e l a t t e r case, background correction, s p e c t r a l i n t e r f e r e n c e c o r r e c t i o n and i n t e r n a l s t a n d a r d i z a t i o n may be necessary t o o b t a i n accurate r e s u l t s , and Brenner and Eldad (C1318) claimed t h a t employing these procedures was p r e f e r a b l e t o assuming t h a t t h e sample composition remained e s s e n t i a l l y constant.For t o t a l contents analysis, t h e concentration r a t i o method (1379) provides a ready check on the accuracy o f t h e data.graph- i c a l procedure f o r i d e n t i f y i n g systematic and random e r r o r s i n r o u t i n e analysis. Short term noise and long term d r i f t (see a l s o Section 3.2) l i m i t t h e p r e c i s i o n and s t a b i l i t y o f c a l i b r a t i o n data. Ramsey and Thompson (C2456) compared c a l i b r a t i o n procedures w i t h and w i t h o u t m a t r i x matching.Meglen and Carr (C1310) described a employed f a c t o r a n a l y s i s t o attempt t o i d e n t i f y sources o f variance i n ICP By using t h e data acquired t o s e l e c t s u i t a b l e i n t e r n a l standards, they able t o improve p r e c i s i o n over 4.5 h from 2.5 t o 0.6%. Larber e t a l . 474. 898, 2522) described a generalized i n t e r n a l reference method based on work o f Barnett e t a l .(Spectrochim. Acta, Part B , 1968, 3, 643 and 1970 139). This i n v o l v e s measuring several i n t e r n a l reference l i n e s t h a t respond i n d i f f e r e n t ways t o v a r i a t i o n s i n t h e operating parameters, and OES. were 473, t h e - 25, each then applying c o r r e c t i o n s based on mathematical transformation o f t h e reference data.I t was found t h a t f l u c t u a t i o n s i n t h e n e b u l i z e r uptake r a t e were responsible f o r t h e s h o r t term f l u c t u a t i o n s , and v a r i a t i o n s i n gas f l o w r a t e s f o r t h e longer term d r i f t . A p p l i c a t i o n o f t h e c o r r e c t i o n procedure reduced l o n g term d r i f t from 10% t o 0.1% and t h e RSD t o 0.1%.A d r i f t c o r r e c t i o n procedure f o r sequential I C P instruments was described by Pyzik (C1135). Abercrombie and Olmstead (C1317) used an e m p i r i c a l formula, i n c o r p o r a t i n g m a t r i x component concentrations and experimentally determined c o e f f i c i e n t s , t o c o r r e c t f o r t h e e f f e c t o f non-specific i n t e r f e r e n c e s due t o s a l t loading.Wallace (1770, 2620) defined t h e necessary c h a r a c t e r i s t i c s f o r i n t e r n a l standards and advocated the use o f h i g h p u r i t y n i t r a t e s o f Sc and Y. A d d i t i o n a l reference on t h e preceding t o p i c - C1899. Spectral i n t e r f e r e n c e s a r e the major cause o f u n c e r t a i n t y i n a n a l y t i c a l data from ICP-OES, and are a l s o responsible f o r s i g n i f i c a n t losses i n d e t e c t i o n power i n samples producing l i n e r i c h spectra.Boumans e t a l . (C1303, 2257, 2258, 2259) demonstrated t h e m e r i t s o f a h i g h r e s o l u t i o n pre-disperser e c h e l l e spectrometer and argued t h a t t h e maximum r e s o l v i n g power t h a t can be employed, c o n s i s t e n t w i t h adequate r a d i a n t f l u x t o overcome shot noise, i s 50 000 - 70 000 i n the U.V.and 60 000 - 100 000 i n the v i s i b l e . They a l s o concluded t h a t background enhancements i n l i n e - r i c h spectra d e r i v e mainly from t h e wings o f20 Analytical Atomic Spectroscopy s t r o n g l i n e s , s, t h e i o n i c l i n e s o f Ca, Me and S r . I'lermet and McLaren (2260; see a l s o C1608, C2423) have reviewed t h e causes o f s p e c t r a l i n t e r f e r e n c e s -1 and employed a h i g h r e s o l u t i o n monochromator (1 m f o c a l l e n g t h , 3600 l i n e s mm g r a t i n g , 1 s t and 2nd o r d e r ) t o s t u d y t h e e f f e c t of r e s o l u t i o n on performance, c o n c l u d i n g t h a t a r e s o l v i n g power o f 150 000 i s o p t i m a l .C r i t e r i a f o r l i n e s e l e c t i o n have a l s o been r e p o r t e d (C1306). 1.2.1.4 I n s t r u m e n t a t i o n I n d u c t i v e l y coupled plasma - mass s p e c t r o m e t r y i s b e i n g used f o r t h e f i r s t t i m e i n a p p l i c a t i o n s l a b o r a t o r i e s and i t appears t h a t i t is a t t r a c t i n g i n c r e a s i n g numbers o f users w i t h b o t h manufacturers r e p o r t i n g b r i s k business.The s u p p l i e r s have, o f course, been a c t i v e a t conferences i n d i c a t i n g t h e performance and p a r t i c u l a r m e r i t s of t h e i r hardware w i t h v a r i o u s sample types (C31, C42, C1200, C1201, C1228, C1338, C1395, C1396, C1429, C1509, C1523, C1942, 1953, 1955, C1979, C2465).Houk (1952). Date (1954) and Gray (C337, C385, C1394, C2462) have reviewed t h e c u r r e n t s t a t u s of ICP-PIS and i n p a r t i c u l a r Gray has d e s c r i b e d i n i t i a l experiments on sample i n t r o d u c t i o n u s i n g e l e c t r o t h e r m a l a t o m i z a t i o n and l a s e r a b l a t i o n .I n a d d i t i o n t o t h e advantages these techniques o f f e r i n o p t i c a l spectrometry, t h e decrease i n t h e l e v e l s o f oxygen e n t e r i n g t h e plasma reduces t h e r e l a t i v e magnitudes o f o x i d e peaks t h a t cause s p e c t r a l i n t e r f e r e n c e s i n I%. S i m i l a r l y , Park and French (C1233, C2000) d e s c r i b e d a Re f i l a m e n t v a p o r i z e r f o r sample i n t r o d u c t i o n t h a t achieved h e a t i n g r a t e s o f 10 000 "C s-' y i e l d i n g pg d e t e c t i o n l i m i t s .Rare e a r t h s a r e n o t o r i o u s l y d i f f i c u l t t o analyse by o p t i c a l methods because o f t h e i r l i n e - r i c h spectra. The CIS s p e c t r a a r e much s i m p l e r and both Date (C1394) and H a l l e t a l .(C30) have r e p o r t e d d a t a on t h e s e elements i n g e o l o g i c a l m a t e r i a l s . The i n t r o d u c t i o n o f a new technique i n t o a p p l i c a t i o n s l a b o r a t o r i e s always produces h i t h e r t o unknown i n t e r f e r e n c e s , and ICP-$lS i s no exception. Users a r e e n c o u n t e r i n g s p e c t r a l i n t e r f e r e n c e s from m o l e c u l a r species and i o n i z a t i o n i n t e r f e r e n c e s .F o r t u n a t e l y , m u l t i p l i c a t i v e i n t e r f e r e n c e s can be handled v e r y e f f e c t i v e l y u s i n g t h e i s o t o p e d i l u t i o n technique, and t h i s has been a p p l i e d t o marine samples by McLaren e t a l .(C1430) and t o environmental m a t e r i a l s by G a r b a r i n o and T a y l o r (C1232). McLeod and Date (C2454) used FI f o r t h e i n t r o - d u c t i o n o f serum samples and determined A l , As, Cd, C r , I, Mn, Mo, Pb, Se, and V a t ug 1-1 l e v e l s . The r a p i d scan c a p a b i l i t y o f quadrupole-mass f i l t e r s i s w e l l s u i t e d t o d a t a a c q u i s i t i o n w i t h t r a n s i e n t s i g n a l s such as t h o s e produced by F I .There have been no s i g n i f i c a n t developments i n t h e use o f t h e I C P as an atom r e s e r v o i r f o r atomic f l u o r e s c e n c e spectrometry, a l t h o u g h G r e e n f i e l d (1034, C1385) has d e s c r i b e d f u r t h e r experiments w i t h a dual plasma system and Winefordner e t a l .(2229; see a l s o C1077) have now p u b l i s h e d a d e s c r i p t i o n o f t h e i r d u a l plasma system (see ARAAS, 1983, 13, 17). F u r t h e r a p p l i c a t i o n s data,Atomization and Excitation 21 from t h e s u p p l i e r s o f commercial ICP-AFS equipment, have been reported covering t h e analysis o f petroleum products (C37), precious metals and p l a t i n g s o l u t i o n s (C338).s t e e l s (2343) and t h e determination o f Hg (C1293). Demers (C1219) described t h e use o f u l t r a s o n i c - n e b u l i z a t i o n w i t h desolvation and achieved t h e expected order o f magnitude improvement i n s e n s i t i v i t y , but a t t h e expense o f increased sample change-over time.A d d i t i o n a l references on t h e preceding t o p i c - C1718, C1941. Low-flow, low-power t o r c h designs based on t h e standard 18 mm format, b u t w i t h a reduced i n t e r - t u b e spacing (0.35 mm), are now commercially available, and t h e r e have been several r e p o r t s o f t h e i r a n a l y t i c a l c h a r a c t e r i s t i c s (C1587).Montaser e t a l . (565) used t h e Simplex o p t i m i z a t i o n procedure t o i d e n t i f y optimum (SBR) compromise c o n d i t i o n s f o r t h i s t o r c h f o r multi-element OES. When operated 720 l;J forward power and a t o t a l gas f l o w o f 5 1 min-’, SBRs f o r 20 elements were s i m i l a r o r o n l y s l i g h t l y i n f e r i o r t o (by a f a c t o r o f 1.5 - 2.0) those obtained w i t h a conventional torch.No conventional chemical i n t e r f e r e n c e s were observed, b u t t h e inteferences from e a s i l y i o n i z a b l e elements were more severe, although these could be reduced by r a i s i n g t h e power. Ng g a t - a l . (C1299) f u r t h e r demonstrated t h a t such torches run a t s i g n i f i c a n t l y reduced powers.Mermet c a l c u l a t e d t h a t t h e minimum i n t e r - t u b e separation r e q u i r i n g an A r f l o w o f 3 1 min-’ t o support t h e p they p r e f e r r e d a 16 mm t o r c h having a tube spacing t o 4.8 1 min-’ o f A r . De Galan’s group have cont cooled torches capable o f operating on f l o w (2251). This year they have described a t o r c h enable organic solvents t o be and co-workers (C1300, 1830) o r an 18 mm t o r c h i s 0.27 mm, asma. For p r a c t i c a l studies o f 0.5 mm and operating down nued t h e i r work on e x t e r n a l l y r a t e s down t o 1 1 min-’ o f A r (C1080, C1452, 2251) t h a t depends on r a d i a t i v e cooling, achieving t h i s by r e p l a c i n g p a r t o f t h e quartz o u t e r tube w i t h boron n i t r i d e , which can run a t s i g n i f i c a n t l y higher temperatures ( 1 600 K ) than quartz.S i m i l a r l y , Haven and Montaser (C1081) commented on the a b i l i t y o f ceramic m a t e r i a l s t o r u n a t higher temperatures and thereby reduce heat losses from t h e plasma, and described a ceramic t o r c h e x t e r n a l l y cooled by a h i g h b o i l i n g p o i n t l i q u i d .The exclusion o f a i r from t h e plasma reduces molecular background emissions. Extended torches have consequently been used f o r t h e determination o f N (C1329, 1323). and an A r sheathed plasma t o r c h was used t o reduce emission from NO thereby improving t h e d e t e c t i o n o f Cd a t t h e 225.802 nm l i n e (471). A d d i t i o n a l reference on the preceding t o p i c - C2429.Other references o f i n t e r e s t - A x i a l l y viewed I C P : 190. Low power generators f o r ICP: C1588, 2045. i,lodulated r.f. generator: 553. Pulsed I C P discharge: C1168.22 Review o f low f l o w torches: 1276. Analytical Atomic Spectroscopy 1.2.1.5 Chromatographic Detection The coupling o f l i q u i d chromatography w i t h ICP-OES has been used i n t h r e e p r i n c i p a l modes: w i t h t h e ICP s e r v i n g as a general purpose d e t e c t o r m o n i t o r i n g C and/or o t h e r elements, f o r t h e s p e c i a t i o n o f m e t a l l i c elements, and f o r t h e separation o f elements p r i o r t o determination, as a means o f avoiding interferences. Each o f these modes i s represented i n t h i s year's reports, notably: as a d e t e c t o r f o r micro-column g e l permeation chromatography (2123, 2509).f o r s p e c i a t i o n o f As and Se (188). f o r s p e c i a t i o n o f organolead compounds (2617). and f o r t h e separation and determination o f rare-earth elements (662, C1402, C1975, 2531). A l l these a p p l i c a t i o n s employ n e b u l i z a t i o n as t h e sample i n t r o d u c t i o n method and t h i s imposes a serious l i m i t a t i o n on t h e s e n s i t i v i t y , p a r t i c u l a r l y f o r micro-bore separations where t h e mobile phase f l o w r a t e s are low.Nisamaneepong and Caruso (C1136) ovecame t h i s d i f f i c u l t y by using an on-line electrothermal atomizer f o r sample i n t r o d u c t i o n .The e f f e c t i v e n e s s of t h e device was demonstrated by t h e determination o f tetraphenyllead and hexaphenyldi lead separated on a micro-sphere reversed-phase column. Other references o f i n t e r e s t - Reviews on coupled HPLC-ICP-OES: 651, C1442. 1.2.2 Microwave-exci t e d Plasmas 1.2.2.1 Fundamental Studies There have been few mechanistic studies o f MIPS d u r i n g t h i s year and t h e v a r i e t y o f c a v i t y and discharge geometries i n use appears t o exclude t h e emergence o f a concensus on energy t r a n s f e r and e x c i t a t i o n mechanisms. For t h e conventional f i l a m e n t plasma, Good e t a l .(C1363) studied t h e e f f e c t o f pressure on plasma parameters and found t h e temperatures t o be r e l a t i v e l y i n s e n s i t i v e t o pressure v a r i a t i o n , whereas t h e r e l a t i v e radiance and e l e c t r o n d e n s i t y changed s u b s t a n t i a l l y .It was postulated t h a t t h i s i m p l i e d t h a t t h e e x c i t a t i o n mechanisms d i d n o t vary w i t h pressure. The same group (C1093) described a procedure f o r c a l o r i m e t r i c measurement o f energy coupling i n microwave c a v i t i e s and published a d e s c r i p t i o n o f t h e i r least-squares f i t t i n g method f o r t h e e s t i m a t i o n o f e l e c t r o n number d e n s i t i e s from Stark p r o f i l e s (1818) (see a l s o ARAAS, 1983, 13, 20). The t o r o i d a l NIP, operated a t atmospheric pressure, (see ARAAS, 1982, 9, Ref. 1378) i s s i m i l a r i n geometry t o t h e ICP and Carnahan & - a l . (C1109) operated such plasmas on a i r , He and N 2 i n d i c a t i n g t h a t t h e r e s u l t i n g A c e n t r a l i n j e c t o r was added t o t r a n s p o r t nebulized aerosol i n t o the plasma. S p a t i a l mapping o f t h e electron-density d i s t r i b u t i o n and o f t h e emissions from He and discharges were 4 - 6 mm i n diameter and 10 mm i n length.A tomization and Excitation 23 atomic and molecular C have been reported (C1108). Mermet e t a l .(C1364) have c a r r i e d o u t a d e t a i l e d spectroscopic study o f an A r plasma generated w i t h a Surfatron. As expected, r o t a t i o n a l temperatures were lower (2000 - 2500 K ) than t h e e l e c t r o n e x c i t a t i o n temperature (4000 K ) and i t was observed t h a t N2 band emission was located mainly i n t h e c e n t r e o f the discharge whereas OH emission was concentrated a t t h e edge o f t h e plasma.A d d i t i o n a l references on t h e preceding t o p i c - 515, C1990. 1.2.2.2 Instrumentation The recent developments i n t o r c h and c a v i t y design and a t r e n d towards t h e use o f higher powers i n microwave plasmas has made i t p o s s i b l e t o introduce samples as aerosols, w i t h o u t desolvation. Even so, w i t h k i n e t i c temperatures n o t exceeding 2500 K, chemical i n t e r f e r e n c e s a r e t o be expected.K o l l o t z e c e t a l . (301) described t h e generation o f t o r o i d a l and 3 f i l a m e n t i4IPs and used t h e l a t t e r f o r t h e determination o f t r a c e elements i n n a t u r a l water, i c e and snow samples introduced by pneumatic nebulization. Detection l i m i t s were i n t h e range 1 - 50 ug m1-l.Caruso e t a l . (C1092, 1847) found i t p o s s i b l e t o introduce aqueous aerosols i n t o an N I P when t h e power was r a i s e d above 500 W, b u t t h e presence o f e a s i l y i o n i z a b l e elements i n t h e sample caused i n t e r f e r e n c e s when an attempt was made t o analyse a s y n t h e t i c sea-water sample.S i m i l a r problems encountered by L e i s and Broekaert (2238) w i t h a He/N2 M I P run a t 800 W. It should be stressed t h a t such high-powered microwave sources a r e extremely hazardous unless p r o p e r l y screened.A mixed Ar/02 M I P sustained i n a t o r c h c o n s i s t i n g o f 2 concentric quartz tubes has been used as an element s p e c i f i c d e t e c t o r f o r Iig species separated by h i g h performance l i q u i d chromatography. The column eluent, a f t e r passing a u.v.-visible d e t e c t o r was dispersed using a pneumatic nebulizer.The authors claimed t h a t the plasma could be sustained on HeOH/H2 mixtures c o n t a i n i n g up t o 90% FleOH (2408). The l i m i t e d atomization e f f i c i e n c y o f M I P S i s i l l u s t r a t e d i n t h e compound-dependent responses Nandro and F r i e d r i c h (C1572) had some success i n overcoming t h i s problem by using two plasmas i n series, t h e f i r s t a c t i n g as a pre-atomizer.Conventionally, inorganic analysis w i t h NIPS has been achieved using ETA as t h e sample i n t r o d u c t i o n procedure. There have been f u r t h e r r e p o r t s o f t h i s approach using metal f i l a m e n t vaporizers (2321, C2471), a W boat vaporizer (2615), and vapour generation furnaces f o r t h e determination o f Hg (2542), and H2, N2 and O2 (C1110).Vapour phase a n a l y t e generation was used by A b d i l l a h i and Snook (C2482) f o r t h e determination o f halogens. A movable coupling loop improved t h e t u n i n g o f a Beenakker c a v i t y (1783), and a quartz tube i n s e r t has been described t h a t c e n t r e - s t a b i l i z e s laminar-flow MIP discharges (C1091). MacLeod e t a l .(C127) described a reduced pressure NIP, f e d w i t h sample from a frit nebulizer, as a source f o r were t h a t l i m i t t h e determination o f atomic r a t i o s .24 Anulytical Atomic Spectroscopy spectrometry. The authors c l a i m advantages over ICP-MS i n terms o f t h e s i m p l i c i t y o f t h e i n t e r f a c e b u t these w i l l be more than outweighed by t h e a n a l y t i c a l disadvantages.A d d i t i o n a l reference on t h e preceding t o p i c - 2280. Other references o f i n t e r e s t - Atmospheric m o n i t o r i n g w i t h an MIP: 108. N~ w: ~1906, 2102, 2103. Single electrode CMP: 1755, 1798. 1.2.2.3 Gas-chromatographic Detection Most MIP-GC d e t e c t o r s a r e l a b o r a t o r y constructed and t h e r e f o r e each year b r i n g s new r e p o r t s o f instrumental developments. Electrodeless plasmas i n quartz discharge tubes a r e most w i d e l y used, but these s u f f e r from e x t i n c t i o n w i t h excessive s o l v e n t loading and are not s u i t a b l e f o r S i determination.Jansen & - a l . (C1388) have f u r t h e r described (see ARAAS, 1983, 13, 21) t h e i r two e l e c t r o d e plasma and demonstrated i t s use f o r t h e detemination o f fluorocarbons.A low frequency He (40 W a t 26.2 kHz) quasi-electrodeless discharge f o r GC d e t e c t i o n was described by Rice e t a l . (C1521). A d e s i r a b l e f e a t u r e o f these devices was t h e i r a b i l i t y t o t o l e r a t e solvent peaks i n t h e eluent. S i m i l a r tolerance t o s o l v e n t loading i n a conventional i-le-MIP has been achieved by power modulation (10 Hz) o f t h e microwaves and operation o f the discharge i n a ceramic tube (261).S l a t k a v i t z e t a l . (C1522) employed boron n i t r i d e and alumina discharge tubes f o r t h e determination o f o r g a n o s i l i c o n compounds. They found t h a t higher powers were r e q u i r e d t o run plasmas i n these tubes unless they were placed i n s i d e a quartz o u t e r tube, i n which case normal power l e v e l s were s a t i s f a c t o r y .A d d i t i o n a l references on t h e preceding t o p i c - C1392. C1518, C1519, C1593, 2632. The a p p l i c a t i o n s o f GC-MIP reported t h i s year included t h e determination o f organomercury compounds (C85), organolead and organosi 1 i c o n compounds (C86).f 1 u o r i n e (C1386). halogenated compounds (C1391). and oxygenated compounds (C1391). The c h a r a c t e r i z a t i o n o f f u n c t i o n a l groups (C87, C1389) and extension o f GC-MIP t o i n o r g a n i c compounds (C1387) has been f a c i l i t a t e d by chemical d e r i v a t i z a t i o n . 1.2.3 D i r e c t Current Plasmas 1.2.3.1 Fundamental Studies P u b l i c a t i o n o f t h e work o f M i l l e r e t a l . (4, ClO99) represents an important advance i n understanding t h e e x c i t a t i o n mechanism o f the DCP. They c h a r a c t e r i z e t h e a n a l y t i c a l zone o f t h e plasma as a n o n - o p t i c a l l y t h i n recombining plasma i n p a r t i a l thermal e q u i l i b r i u m .Regarding t h e e f f e c t o fA to mizat ion and Excitation 25 e a s i l y i o n i z a b l e elements on analyte emission they reported f o u r conclusions: ( 1 ) t h e i n t e r f e r a n t a c t s mainly t o p e r t u r b r a d i a t i o n a l t r a n s f e r r a t h e r than c o l l i s i o n a l energy r e d i s t r i b u t i o n ; ( 2 ) population pumping o f e x c i t e d analyte s t a t e s i s l a r g e l y d r i v e n by Penning i o n i z a t i o n ; (3) t h e i n t e r f e r a n t produces accelerated r a d i a t i v e c o o l i n g and lowers l o c a l k i n e t i c temperatures; (4) ambipolar d i f f u s i o n .a n a l y t e - i n t e r f e r a n t c o l l i s i o n s o f the second k i n d and analyte ground-state s p i n do not i n f l u e n c e l i n e enhancement.Sneddon and Fuavae (C123) observed no change i n the e l e c t r o n e x c i t a t i o n temperature when e a s i l y i o n i z a b l e elements were added and used an A l / L i b u f f e r s o l u t i o n t o reduce the i n t e r f e r e n c e e f f e c t s , E l l i o t and Barnes (C1098) used laser-Doppler velocimetry t o study aerosol dynamics and found a low v e l o c i t y r e g i o n corresponding t o t h e normal a n a l y t i c a l zone, although penetration o f t h i s zone by t h e aerosol was r e l a t i v e l y i n e f f i c i e n t .Blades and Lee (C1362, 1799) mapped atom and i o n l i n e i n t e n s i t i e s and e l e c t r o n concentrations i n t h e DCP and found s i m i l a r i t i e s w i t h the ICP i n t h a t t h e ion/atom r a t i o s were lower than would be expected from a plasma w i t h an e l e c t r o n concentration i n t h e range 2 - 6 x l O I 5 ~ r n - ~ .o f plasma core s h i f t s i n the DCP and separated t h e e f f e c t o f desolvation o f d r o p l e t s by i n t r o d u c i n g propane d i r e c t l y i n t o t h e i n j e c t o r gas.The propane produced i d e n t i c a l s h i f t s t o those produced by organic solvent aerosols and t h e r e f o r e t h e s h i f t s were a t t r i b u t e d d i r e c t l y t o t h e presence o f diatomic molecules. A study o f vacuum u l t r a v i o l e t spectra i n t h e DCP revealed high energy l i n e s o f CII, NII, PI1 and SII, n o t found i n the I C P (304).Helium (C1528) has been added t o a DCP i n an attempt t o enhance emission o f h i g h energy l i n e s from t h e halogens, N and 0. Boyko and K e l i h e r (C49) have continued t h e i r work on t h e causes 1.2.3.2 Instrumentation Plost o f t h e p u b l i c a t i o n s t h i s year d e s c r i b i n g instrumental developments r e l a t e t o sample i n t r o d u c t i o n . Mangold and Bastiaans (956) have now published (see ARAAS, 1983, 13, 23) t h e i r conclusions on t h e use o f N2 as t h e n e b u l i z e r gas, f i n d i n g t h a t i f o f f e r s no advantages. S l u r r y n e b u l i z a t i o n has been employed f o r t h e i n t r o d u c t i o n o f r e f r a c t o r y carbides (C74) and t h e r e has been f u r t h e r r e p o r t s (C20, C125) o f t h e use o f e m u l s i f i e r s (see ARAAS, 1983, 73, 23) f o r i n t r o d u c i n g organic solvents as f i n e suspensions (see a l s o Section 1.3.3). Flow i n j e c t i o n has been employed as a means o f avoiding n e b u l i z e r blockage, when b i o l o g i c a l m a t e r i a l s were introduced i n t o t h e DCP (C1295). To analyse pyrophoric group I11 - VA metal a l k y l s , used i n semiconductor manufacture, i t was found necessary t o enclose t h e plasma i n an i n e r t gas (C1531). This procedure produced marked changes i n t h e plasma and a f f e c t e d t h e a n a l y t i c a l s e n s i t i v i t y o f many elements. A d d i t i o n a l references on t h e preceding t o p i c - 441, 792.26 Analytical Atomic Spectroscopy Savolainen e t al. (C54, C600 commented t h a t t h e normal +3% r e l a t i v e standard d e v i a t i o n obtained w i t h t h e DCP i s inadequate f o r many a p p l i c a t i o n s and t h e r e f o r e developed improved methodology, i n c l u d i n g instrument m o d i f i c a t i o n s and modified c a l i b r a t i o n procedures,= t h a t y i e l d e d an RSD o f 50.5%. F r a l e y (C61) employed i n t e r n a l s t a n d a r d i z a t i o n t o improve t h e precision. Other references o f i n t e r e s t - C i r c u l a r t h i n f i l m plasma source: 918. D i r e c t c u r r e n t plasma j e t : 257. Graphi t e - f i 1 ament plasma: C46. 1.2.3.3 Chromatographic Detection Most workers employing t h e DCP as a d e t e c t o r f o r h i g h performance l i q u i d chromatography have used t h e n e b u l i z e r based sample i n t r o d u c t i o n system unmodified, but Nazzo e t a l . (2322) studied sample i n j e c t i o n v e l o c i t i e s i n t o t h e plasma, using laser-Doppler velocimetry, and modified t h e i n j e c t o r chimney diameter t o improve t h e e f f i c i e n c y . Boorn and Thomas (C1397) discussed t h e d i f f i c u l t i e s o f i n t e r f a c i n g t h e standard DCP commercial instrument t o HPLC and c i t e d t h e d.c. s i g n a l d e t e c t i o n e l e c t r o n i c s , t h e necessity f o r making background c o r r e c t i o n s on t r a n s i e n t signals, and l i m i t e d d e t e c t i o n power as problems r e q u i r i n g a t t e n t i o n . The l i m i t e d s e n s i t i v i t y f o r Sn was overcome by K r u l l (C1529) using continuous hydride generation on t h e column e l u e n t t o achieve d e t e c t i o n l i m i t s o f 20 - 100 pg 1-’ f o r organotin compounds. The same author (493) described t h e separation and determination o f Cr( 111) and Cr(V1) species i n environmental samples, o b t a i n i n g d e t e c t i o n l i m i t s i n t h e 5 - 10 ug 1-1 range.

ISSN:0306-1353    

DOI:10.1039/AA9841400008

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

26 Analytical Atomic Spectroscopy 1.3 FLAMES The r o u t i n e use o f flames i n a n a l y t i c a l atomic spectrometry must r a t e as one o f t h e most s t a t i c f i e l d s o f a p p l i e d science. Although each y e a r ' s review o f t h i s t o p i c reveals a number o f novel and i n t e r e s t i n g developments, very few o f these ever f i n d t h e i r way i n t o r o u t i n e a p p l i c a t i o n .The r e l e v a n t p u b l i c a t i o n s i n 1984 again suggest t h a t t h i s i s an e x c i t i n g b u t f r u s t r a t i n g area o f research a c t i v i t y . Perhaps FI sample i n t r o d u c t i o n w i l l become commercially a v a i l a b l e f o r AAS instruments, and i t s p o p u l a r i t y suggests t h a t i t should, b u t t h e r e appears t o be no commercial i n t e r e s t i n l a s e r AFS and LEI, d e s p i t e t h e widespread demonstration o f a p p l i c a t i o n s i n t h e c u r r e n t year.P o s s i b l y t h e d i f f i c u l t y o f using l a s e r s and t h e c o s t o f e s t a b l i s h i n g new instruments based on e i t h e r o f these technologies remains p r o h i b i t i v e . b u t evidence produced from t h e s l o t t e d tube suggests t h a t manufacturers might gain from t h e i n t r o d u c t i o n of novel low-cost hardware f o r t h e i r flame instruments.Atomization and Excitation 27 Two r a t h e r d i f f e r e n t kenera1 papers stand o u t from t h e l i t e r a t u r e i n 1984. An exhaustive review of methods f o r t h e measurement o f temperatures i n flames has been given (2281), and t h e Instrumental C r i t e r i a Sub-Committee o f t h e A n a l y t i c a l Methods Committee o f the Royal Society o f Chemistry produced a valuable r e p o r t on t h e importance o f s p e c i f i c design features i n FAAS instruments (767).This r e p o r t was published i n f u l l i n ARAAS l a s t year (ARAAS, 1983, 13, Section 2.6.2) and should undoubtedly be read by anyone contemplating t h e purchase o f a new instrument. T h e i r second r e p o r t on electrothermal atomizers i s reproduced i n Section 2.6.2. 1.3.1 Fundamental Studies The b u r n t gas composition o f a p o t e n t i a l l y important atom r e s e r v o i r , t h e helium/oxygen/acetylene flame was c a l c u l a t e d using a s l i g h t m o d i f i c a t i o n o f t h e Dankoehler and Edse i t e r a t i o n procedure (1751; see a l s o ARAAS, 1980, E, 48).The m o d i f i c a t i o n s allowed f o r t h e replacement o f N2 by He, and t h e assumption t h a t t h e l a t t e r was unreactive and served o n l y as a d i l u e n t . The composition a t 2735 K was expressed as t h e p a r t i a l pressure o f CO, C02, H, He, H2, H20, 0, OH, and O2 c a l c u l a t e d from e q u i l i b r i u m constant data.It was concluded t h a t compared t o t h e air/C2H2 flame, t h e He/02/C2H2 flame provides a s l i g h t l y more reducing and a much l e s s quenching environment, which could make i t a t t r a c t i v e f o r use i n AFS. The atomization o f i o d i n e i n entrained-air/H2 flames d i l u t e d w i t h A r o r N2 has been studied (2342).The AAS s e n s i t i v i t y was enhanced by a f a c t o r o f 250 by p r i o r o x i d a t i o n o f t h e i o d i d e t o I 2 using a c i d i f i e d dichromate, presumably due t o increased t r a n s p o r t e f f i c i e n c y . E i t h e r flame y i e l d s I absorbance values a f a c t o r o f 8 higher than t h e f u e l - r i c h air/C2H2 flame.Improvements i n t h e AAS s e n s i t i v i t y compared t o t h e air/C2H2 flame have been reported f o r several elements when using e i t h e r t h e N20/C3H8 flame, o r combustible aerosols such as E t O H o r acetone (as t h e f u e l ) w i t h a i r o r IJ20 (2390). studies o f t h e tandem flame concept have been presented by Boss & - a l .(C1144, C1166, C1553). I n t h i s system, a second independently a d j u s t a b l e flame was constructed i n tandem w i t h t h e flame from a conventional burner. A p a i r o f burners, constructed by s i l v e r s o l d e r i n g two rows o f 18 s.1v.g. hypodermic t u b i n g i n t o s t a i n l e s s s t e e l rods, were mounted on e i t h e r s i d e of and p a r a l l e l t o t h e s l o t o f t h e primary burner.Both t h e h e i g h t and transverse p o s i t i o n o f t h e secondary burner, as w e l l as t h e angle o f o r i e n t a t i o n w i t h respect t o the primary burner, can be adjusted. When a n a l y t e s o l u t i o n s a r e introduced, t h e primary flame i s used mainly t o vaporize t h e sample, and t h e second t o decompose vapour phase molecular species.Higher s e n s i t i v i t i e s i n both AAS and AES measurements, and a r e d u c t i o n o f m a t r i x i n t e r f e r e n c e s were claimed even though t h e temperatures are no higher than i n conventional flames. Further28 Analytical Atomic Spectroscopy Emission enhancements were s a i d t o be due t o c o l l i s i o n s between analyte and energetic species from t h e secondary flame a t t h e p o i n t o f e n t r y o f t h e sccondary f 1 ame.Several novel m o d i f i c a t i o n s have been i n v e s t i g a t e d w i t h hydrogen-based flames. A N2 separated/02/H2 flame has been described f o r t h e determination of sulphur compounds by NECA (835). A H - r i c h mixture o f 0 and H2 i s introduced a t t h e c e n t r e o f a t o t a l consumption burner.Provided t h a t t h e O2 i s consumed immediately, i n t e n s e S2 emission i s observed from t h e MECA c a v i t y . The authors c l a i m t h a t t h e temperature and composition o f t h i s flame can be c o n t r o l l e d more e x a c t l y than w i t h a conventional N2/entrained-air/H2 d i f f u s i o n flame.Emission i n t e n s i t i e s o f HPO and SnH i n an 02/H2 flame were shown t o be p a r t i a l l y quenched by a magnetic f i e l d (2075). A N2 separated i n v e r t e d air/H2 flame was operated on a b o r o s i l i c a t e - g l a s s low-temperature burner, and was used f o r t h e measurement o f HPO emission, a t 528 nm (1458). A i r w i t h N2 was introduced through a c e n t r a l tube w i t h a m i x t u r e o f H2 and N2 and t h e nebulized t e s t sample i n an o u t e r tube, w i t h t h e N2 sheath gas e x t e r n a l t o t h i s .A l i n e a r c a l i b r a t i o n f o r P [ a s (NH4)2HP04] from 0.05 t o 1000 ug 1-1 was obtained. A CW r i n g dye-laser was used t o o b t a i n a two-dimensional image o f t h e molecular absorption o f YO i n a premixed air/C2H2 flame (1835).S p a t i a l l y resolved v i b r a t i o n a l e x c i t a t i o n temperatures were obtained by measurement o f t h e absorption from d i f f e r e n t v i b r a t i o n a l l e v e l s o f t h e molecular ground s t a t e o f YO, presented as a two-dimensional image on a v i d i c o n camera. 2 2 The study o f t h e p o t e n t i a l use o f s p e c i f i c isotope hollow cathode lamps f o r t h e AAS determination o f r a t i o s o f Pb isotopes has now been published (2265; see ARRAS, 1983, 3, 25).It was shown t h a t t h e measured line-width o f the 283.3 nm Pb i s 0.00152 nm i n air/C2H2 and 0.00189 nm i n an air/H2 flame, t h e d i f f e r e n c e being due t o d i f f e r e n c e s i n t h e c o l l i s i o n a l broadening.Line s h i f t s o f t h e order o f 0.00038 nm were a l s o observed i n both flames. The study showed t h a t i s o t o p i c determinations o f Pb can o n l y be made i n a low temperature atom c e l l such as i s produced by cathodic s p u t t e r i n g i n a low pressure discharge. l i n e Further studies o f t h e e f f e c t o f s t r a y l i g h t on t h e c a l i b r a t i o n f u n c t i o n i n AAS have been reported (C1557; see a l s o ARAAS, 1983, 13, 25).A new c a l i b r a t i o n a l g o r i t h m has been proposed f o r AAS (1820). The f u n c t i o n : c = K~ ( K ~ A + K,A~) / ( K ~ A - 1) where C i s the concentration, A t h e absorbance, and KO, K I T K2, K3 experimentally derived c o e f f i c i e n t s , was shown t o f i t t h e a n a l y t i c a l l y u s e f u l range o f AAS c a l i b r a t i o n curves obtained i n an air/C2H2 flame. A c r i t i c a l assessment o f c u r r e n t l y a v a i l a b l e AA-instrument c a l i b r a t i o n computer programmesAtomization and Excitation 29 has been made and disadvantages defined (845).When t h e standard a d d i t i o n s method i s used t o overcome t h e e f f e c t o f a m a t r i x interference, t h e shape o f the absorbance versus i n t e r f e r a n t concentration p l o t must be taken i n t o account.An i n t e r e s t i n g paper by de Galan e t a l . (1803) has shown t h a t r o l l - o v e r o f c a l i b r a t i o n curves should occur i n t h e Smith-Hieftje method o f background c o r r e c t i o n , and t h i s has now been confirmed experimentally. A microcomputer programme f o r t h e modified Simplex method has been optimize t h e a n a l y t i c a l c o n d i t i o n s f o r t h e flame AAS determination sea-water (2304).A s t a t i s t i c a l design o f experiments has a l s o been optimize c o n d i t i o n s under which t h e random and systematic e r r o r s measurements are minimized (2541).High p r e c i s i o n and accuracy were f o r C r a t 50 - 400 ug m l - 1 i n t h e presence o f S i and W. The development o f continuum source atomic absorption cont accelerate (322, 327, C335, C409, 873, C1188), and a u s e f u l review has used t o o f L i i n used t o n C r AAS achieved nues t o appeared during t h e year (826). The s e l e c t i o n o f compromise flame c o n d i t i o n s f o r t h e determination o f a range o f elements i n b i o l o g i c a l m a t e r i a l s has been w e l l characterized (873, C1188; see ARAAS, 1983, 2, 26).A new modulation waveform, r e f e r r e d t o as a s t a i r c a s e waveform, has s u b s t a n t i a l l y reduced the number o f measurements r e q u i r e d over t h e wavelength modulation c y c l e f o r the c o n s t r u c t i o n o f AAS c a l i b r a t i o n curves over 4 - 6 orders o f concentration (327).The analysis and computing time required f o r t h e simultaneous measurement o f 9 elements i n 10 standards and 13 samples i s now reduced t o 25 min. A s i n g l e channel continuum source AAS system i n which a microcomputer i s used t o c o n t r o l t h e wavelength modulation u n i t and perform data a c q u i s i t i o n and data processing has a l s o been described (C335, C409). 1.3.2 Atomization and I n t e r f e r e n c e Studies There appears t o be renewed i n t e r e s t i n t h e use o f t h e s i n g l e d r o p l e t generator f o r the study o f v a p o r i z a t i o n and atomization phenomena i n flames. F i r s t introduced by t l i e f t j e and Walmstadt i n 1968 (Anal.Cbem.. 1968, 40, 1960), the d r o p l e t generator has found a p p l i c a t i o n i n a number o f studies over t h e years (see f o r example ARAAS, 1981, 11, 25), and some new work has been presented i n 1984 (C1117, C1556, C1571, C1962). Laser l i g h t s c a t t e r i n g has been used t o monitor t h e aerosol p a r t i c l e v o l a t i l i z a t i o n process as a f u n c t i o n o f time and space (C1117).I n t h i s procedure an Ar-ion l a s e r was used t o determine t h e s i z e o f s o l u t e p a r t i c l e s i n an air/C2H2 flame as a f u n c t i o n o f residence time. Atomic vapour d i s t r i b u t i o n s a f t e r d i s c r e t e d r o p l e t i n t r o d u c t i o n were followed using atomic emission and l a s e r AFS (LAFS) w i t h spectrometric d e t e c t i o n systems capable o f both s p a t i a l and temporal r e s o l u t i o n (C1571).The LAFS method provides a three-dimensional s p a t i a l d i s t r i b u t i o n o f atoms w i t h o u t t h e need f o r Abel inversion.30 Analytical Atomic Spectroscopy The s i n g l e d r o p l e t generator has a l s o been used t o study t h e enhancement e f f e c t o f s u r f a c t a n t s on flame spectrometric s i g n a l s (C1556).Recent work has suggested t h a t t h e enhancements are caused by aerosol i o n i c r e d i s t r i b u t i o n (see ARAAS, 1982, 12, 29). b u t s t u d i e s by Black e t a l . (C1556) have now suggested t h a t the enhancements a r e n o t due t o a s i n g l e mechanism.Enhancements o f C r and Cu are n o t dependent on t h e type o f s u r f a c t a n t used, b u t the magnitude o f enhancement does depend on flame composition, being g r e a t e r under f u e l - r i c h flame conditions. I t has a l s o been shown t h a t f o r a given d r o p l e t size, a drop c o n t a i n i n g s u r f a c t a n t vaporizes more r a p i d l y than does one without.Enhancement o f AA measurements o f T i and V i n t h e N20/C2H2 flame were a l s o found t o be independent o f t h e nature o f t h e s u r f a c t a n t (2519). Enhancements o f t h e order o f 180 t o 150% were obtained f o r T i and V r e s p e c t i v e l y , and l i n e a r p o r t i o n s o f c a l i b r a t i o n graphs were extended by a f a c t o r o f 2.The mechanism was s a i d t o be due t o t h e production o f smaller d r o p l e t s d u r i n g nebulization, obviously due t o t h e lower surface tension. Surfactants were a l s o used t o overcome t h e problems caused by t h e presence o f f a t t y o i l s i n waste water samples (995). Once again t h e e f f e c t was independent o f t h e type o f s u r f a c t a n t used, b u t t h e amount was c r i t i c a l , about 0.2 - 1.0% s u r f a c t a n t being r e q u i r e d t o produce a s t a b l e emulsion o f f a t t y o i l s a t concentrations up t o 10%.Polymers i n s o l u t i o n have been shown t o cause i n t e r f e r e n c e e f f e c t s i n both AAS and AES (747. C1703. 2499).Aqueous polyacrylamide s o l u t i o n s were analysed f o r K, L i and Na by AES and f o r Ca, Mg and Pln by AAS, and t h e s i g n a l depressions were a t t r i b u t e d t o both decreased n e b u l i z a t i o n e f f i c i e n c y and decreased atomization e f f i c i e n c y . The degree o f d i s s o c i a t i o n , degree o f i o n i z a t i o n and f r e e atom f r a c t i o n s o f Ba, Ca, Mg and S r have been c a l c u l a t e d f o r n i n e flames includng t y p i c a l a n a l y t i c a l flame mixtures as w e l l as 02/C2H2 and 02/C2N2 (C1710).Both t h e temperature and flame composition were taken i n t o account. Estimation o f t h e v a p o r i z a t i o n r a t e o f aerosol i n t h e a i r / C H flame explained many m a t r i x e f f e c t s and t h e p r o p e r t i e s o f La as a b u f f e r i n g agent (C1710). C a l c u l a t i o n s based on t h e minimization o f t h e Gibbs f r e e energy were used t o deduce t h e degree o f d i s s o c i a t i o n o f Sn i n N2/02/H2 flames (2206).It was shown as expected, t h a t t h e degree o f atomization o f Sn increases w i t h decreasing excess o f 02. Measurement o f t h e d i s t r i b u t i o n o f atoms i n air/C2H2 flames was used t o i n v e s t i g a t e mass t r a n s f e r and d i s s o c i a t i o n processes i n t h e flame f o l l o w i n g various sample i n t r o d u c t i o n techniques (2596).D i f f u s i o n , convection, formation o f t h e r m a l l y s t a b l e compounds, and t h e temperature o f t h e a n a l y t i c a l zone were found t o be t h e major influences on atom concentrations.The e f f e c t o f metal-ligand i n t e r a c t i o n s i n s o l u t i o n on t h e v a p o r i z a t i o n and atomization processes o f aerosol p a r t i c l e s i n an air/C2H2 flame have been by s p a t i a l d i s t r i b u t i o n measurements using narrow HCL 1 i g h t beams (C1706). 2 2 characterizedAtomization and Excitation 31 A novel approach t o t h e measurement o f atomization c o e f f i c i e n t s ( f r e e atom f r a c t i o n ) was proposed by Zaidel (2099). Using r a d i o a c t i v e isotopes of t h e elements o f i n t e r e s t , t h e atomization c o e f f i c i e n t can be c a l c u l a t e d from t h e r a t i o o f t h e o p t i c a l atomic s i g n a l and t h e nuclear r a d i a t i o n o r i g i n a t i n g i n t h e same volume o f t h e atomizer. The simplest approach was by t h e simultaneous measurement o f 6 o r y r a d i a t i o n and saturated resonance fluorescence.The apparatus may be c a l i b r a t e d by assuming t h a t t h e atomization c o e f f i c i e n t s o f Ag, Cu, and Hg are near u n i t y , b u t t h e s p e c i f i c a c t i v i t i e s o f d i f f e r e n t i s o t o p i c species must s t i l l be known, An i n t e r e s t i n g c o n t r i b u t i o n t o t h e study o f t h e i o n i z a t i o n behaviour o f r a r e elements i n t h e N20/CzH2 flame has produced some u s e f u l data (648).Using t h e AA method o f Manning and Delgado (Anal. Chim. Acta, 1966, 36, 312) i o n f r a c t i o n s as h i g h as 0.65, 0.42, 0.79, 0.18, and 0.35 were deduced f o r 0.1 mM s o l u t i o n s o f Dy, E r , Eu, Sc, and Yb, r e s p e c t i v e l y .The absorbances o f t h e atomic l i n e s increased w i t h t h e concentration o f added K and became constant a t 0.01 M; the absorbances o f t h e i o n l i n e s decreased i n a d i r e c t r e l a t i o n s h i p .e a r t h 1.3.3 Devices f o r Sample I n t r o d u c t i o n The number o f novel a p p l i c a t i o n s studies i n d i c a t e s t h e continued p o p u l a r i t y o f f l o w i n j e c t i o n sample i n t r o d u c t i o n . Although not i n the same league, the s l o t t e d tube introduced commercially by one manufacturer has a l s o jumped i n t o prominence.Once again t h e l i t e r a t u r e on micro-sampling devices has been placed i n two separate sections covering micro-sampling v i a t h e n e b u l i z e r (1.3.3.2) and micro-sampling d i r e c t l y i n t o t h e flame (1.3.3.3). Although t h e s e c t i o n on nebulizers (1.3.3.1) covers those papers r e l a t e d s p e c i f i c a l l y t o flames, i n t e r e s t e d readers should a l s o c o n s u l t Section 1.2.1.2 since much c u r r e n t research on n e b u l i z e r design and performance, although r e l e v a n t t o flame operation, i s aimed a t t h e i r use i n t h e ICP f i e l d . 1.3.3.1 Nebulizers Amongst new n e b u l i z e r s r e p o r t e d d u r i n g 1984 was a mini-nebulizer s u i t a b l e f o r on-line monitoring o f r a d i o a c t i v e samples i n which cross contamination was e l i m i n a t e d (2100).and a commercial system which has a heater i n s t a l l e d w i t h i n t h e m i s t d i s p e r s e r ( o r impactor) (922). It was claimed t h a t a system w i t h PTFE burner/nebulizer f i t t i n g s e l i m i n a t e d t h e instrument noise associated w i t h c o r r o s i o n deposits i n t h e i n l e t s o f the f u e l and a u x i l i a r y gas t u b i n g (521).Once again, Pearce and Boss, i n a conference presentation, have described t h e i r i n t e r e s t i n g approach t o t h e c o n t r o l o f t h e d r o p l e t s i z e d i s t r i b u t i o n of t h e aerosol reaching a flame (C1559; see ARAAS, 1983, 5, Section 1.3.3.1). The method i s r e f e r r e d t o as coulombic manipulation and c o n s i s t s o f applying an e l e c t r i c f i e l d perpendicular t o flame gas and aerosol f l o w i n t h e r e g i o n o f t h e32 Analytical Atomic Spectroscopy burner head.Cresser e t a l . have produced a number o f i n t e r e s t i n g r e p o r t s on n e b u l i z e r performance i n t h e past year (319, 1866, C2487, C2557, C2635; see a l s o Section 1.2.1.2).A pressure transducer was used t o make n e b u l i z e r s u c t i o n measurements (C2557). It was shown t h a t changes i n s u c t i o n and atomic absorbance readings are r e l a t e d , as both depend on the a s p i r a t i o n r a t e . Changes i n s u c t i o n were used t o compensate continuously f o r d r i f t s i n a s p i r a t i o n r a t e via microcomputer feedback.Useful comments have a l s o been made on t h e r o l e o f impactors i n n e b u l i z a t i o n processes (C2487, C2635). Although impact beads may g i v e r i s e t o s i g n i f i c a n t improvements i n s e n s i t i v i t y due t o improved t r a n s p o r t e f f i c i e n c y , the e x t r a aerosol reaching t h e flame may have an unfavourable e f f e c t on t h e d r o p l e t s i z e d i s t r i b u t i o n , and lead t o increased curvature o f c a l i b r a t i o n graphs and i n t e r f e r e n c e s from incomplete v o l a t i 1 i z a t i on.Measurements o f t h e s u c t i o n o f a pneumatic n e b u l i z e r have a l s o been used t o e x p l a i n t h e noise problems associated w i t h branched c a p i l l a r y n e b u l i z a t i o n (319), a technique which has a l s o been used t o develop a new procedure f o r t h e determination o f B i , Hg and Sb i n geochemical samples (292).The t e s t s o l u t i o n i s introduced through one branch, and a borohydride s o l u t i o n through the other. S e n s i t i v i t i e s (1% absorption) o f 0.02. 0.13 and 0.022 ug m1-I were obtained f o r B i , Hg and Sb r e s p e c t i v e l y .Once again a number o f a p p l i c a t i o n s o f t h e emulsion technique have appeared (811, 1236, 1266, 1792; see a l s o Section 1.2.3.2). These papers a r e mainly concerned w i t h t h e determination o f metals i n l u b r i c a t i n g (811, 1266) o r f u e l o i l s (1236), using c a l i b r a t i o n s o l u t i o n s prepared i n a s i m i l a r emulsion m a t r i x using aqueous standards.The use o f organicjwater and water/organic emulsions has been compared w i t h t h e determination o f Cu and Fe by d i r e c t a s p i r a t i o n o f t h e i r APDC complexes i n M I B K (1792). A number o f advantages were claimed. Aqueous standards may be used i f e m u l s i f i e d w i t h M I B K i n t h e same way as t h e standards. The organic phase enhances s e n s i t i v i t y , and t h e MIBK e x t r a c t s t a b i l i t y i s increased from 2 hours t o 3 weeks f o r t h e water/organic emulsion.The use o f a carbonaceous s l u r r y f o r the FAAS determination o f Ca, Fe, K, Me, Mn and Zn has been extended t o a number o f d i f f e r e n t vegetable m a t e r i a l s (C371, 653; see a l s o ARAAS, 1983, 3, Ref. 1089). The s l u r r i e s were produced by warming t h e samples w i t h concentrated H2S04 and d i l u t i n g w i t h H20. A s l u r r y method has a l s o been developed f o r t h e determination o f K and Na i n hot dogs (744). The sample i s simply homogenized i n H20 and t h e s l u r r y sprayed d i r e c t l y i n t o a clog-free a i r / n a t u r a l gas burner via a Babington nebulizer.Other reference o f i n t e r e s t - The e f f e c t o f p a r t i c l e s i z e i n t h e d i r e c t a n a l y s i s o f suspensions: C1704. One simple accessory which could be o f f e r e d by manufacturers i s a k i t whichAtomization and Excitation 33 f a c i l i t a t e s t h e atom t r a p p i n g procedure (see ARAAS, 1982, 11, 31).I n t h i s method, samples a r e i n t r o d u c e d v i a t h e n e b u l i z e r i n a c o n v e n t i o n a l manner, b u t a r e trapped on a water cooled tube h e l d i n an air/C2H2 flame. Subsequently, c o l l e c t i o n i s stopped and t h e atoms r e l e a s e d as a p u l s e when t h e c o o l i n g water f l o w i s stopped.The AAS s e n s i t i v i t y achieved by measurement o f t h e t r a n s i e n t s i g n a l approaches t h a t o f ETA-AAS. I n a u s e f u l overview o f t h i s method, Ure o u t l i n e d t h e wide range o f elements and sample types t o which t h e method has been a p p l i e d (C1729). A number o f i n t e r e s t i n g m o d i f i c a t i o n s have been d e s c r i b e d by Hallam and Thompson (C2449).Using a s p i r a t i o n t i m e s as l o n g as 2 min, and a p a r a l l e l p a i r o f 3 mm 0.d. aluminium o x i d e coated s i l i c a tubes 1 mm a p a r t , a d e t e c t i o n l i m i t (quoted as a c r i t e r i o n o f d e t e c t i o n ) o f 2 ug 1-I was achieved f o r Pb. The method was a p p l i e d t o t h e a n a l y s i s o f p o t a b l e water samp 1 es. 1.3.3.2 Nicro-Sample I n t r o d u c t i o n v i a t h e N e b u l i z e r The technique o f t e n r e f e r r e d t o as p u l s e n e b u l i z a t i o n , b u t termed here d i s c r e t e sample n e b u l i z a t i o n , c o n t i n u e s t o f i n d g e n u i n e l y new a p p l i c a t i o n s . I t i s o f course p a r t i c u l a r l y a p p r o p r i a t e f o r t h e i n t r o d u c t i o n o f m e t a l s i n o r g a n i c s o l v e n t s a f t e r s o l v e n t e x t r a c t i o n procedures (240, 254).t h e d e t e r m i n a t i o n o f Te a f t e r e x t r a c t i o n i n t o methyl methacrylate/blIBK appearing t o be novel and p a r t i c u l a r l y noteworthy (254). I n a general survey o f sample i n t r o d u c t i o n procedures i n c l u d i n g c o n v e n t i o n a l n e b u l i z a t i o n , d i s c r e t e sample n e b u l i z a t i o n , d i s c r e t e sample n e b u l i z a t i o n w i t h t h e s l o t t e d tube, Delves cup, and 140 w i r e loop, t h e d i s c r e t e sample n e b u l i z a t i o n method was p r e f e r r e d f o r t h e d e t e r m i n a t i o n o f Cu and Zn i n b l o o d plasma f r a c t i o n s (263).P a r t i c u l a r advantages f o r t h i s a p p l i c a t i o n were s i m p l i c i t y and h i g h sample throughput. Prudnikov e t a l . have a p p l i e d t h e d i s c r e t e sample n e b u l i z a t i o n method t o t h e a n a l y s i s o f n o b l e m e t a l s i n low q u a l i t y o r e s and f l o t a t i o n t a i l i n g s (575).and have a l s o demonstrated a m o d i f i c a t i o n which a l l o w s t h e use o f 0.1 - 1.0 u 1 volumes o f sample s o l u t i o n which reduces a b s o l u t e d e t e c t i o n l i m i t s t o t h e lo-'' g range (C384, 2059). A vacuum d e s i c c a t o r system was d e s c r i b e d f o r t h e c o n t a m i n a t i o n - f r e e p r e c o n c e n t r a t i o n o f samples f o r a n a l y s i s by d i s c r e t e sample nebul i z a t i o n (1868).Combination o f an automated d i s c r e t e sample n e b u l i z a t i o n apparatus w i t h a s l o t t e d t u b e atom t r a p i s now o f f e r e d commercially by one manufacturer (C332, 446, C1554, C1745, 1372, C2453; see ARAAS, 1983, 13, 30). The commercial v e r s i o n has two s l o t s o f 40 mm and 50 mrn l e n g t h machined l a t e r a l l y i n t h e q u a r t z t u b e a t an angle o f s e p a r a t i o n o f 180" (C1554, C1745).Although an a n g l e o f 120" was found t o g i v e s l i g h t l y improved s e n s i t i v i t y , t h e 130" a n g l e a l l o w s e a s i e r a1 ignment w i t h t h e b u r n e r s l o t , a p p a r e n t l y e a s i e r manufacture, and s i g n i f i c a n t l y improved p r e c i s i o n .I t a l s o a l l o w s t h e more e f f i c i e n t upward34 Analytical Atomic Spectroscopy v e n t i n g o f exhaust gases. Other tube designs were investigated, and a p p l i c a t i o n s t o a wide range o f elements and sample types have now been demonstrated (see a l s o Section 1.3.3.4). A new method o f sample i n t r o d u c t i o n has been proposed f o r f l o w i n j e c t i o n AAS (C2445).The method uses a p e r i s t a l t i c pump d r i v e n by a microcomputer-controlled stepping motor. A probe connected t o t h e pump tube i s t r a n s f e r r e d t o t h e sample cup w h i l e t h e pump i s stationary. The pump i s then a c t i v a t e d f o r a given time t o draw a p r e c i s e volume o f sample through t h e probe.When t h e pump i s again s t a t i o n a r y , t h e probe i s returned t o a r e s e r v o i r c o n t a i n i n g c a r r i e r s o l u t i o n , and subsequently t h e pump i s r e a c t i v a t e d t o i n t r o d u c e c a r r i e r s o l u t i o n which passes t h e sample through t h e AAS system. Since o n l y t h e r e q u i r e d amount o f sample i s used, t h e wastage o f t h e r o t a r y valve sample i n t r o d u c t i o n method i s avoided.It seems l i k e l y t h a t t h i s method would be p a r t i c u l a r l y easy t o adapt t o modern computer-control l e d AAS instruments. Studies o f t h e continuous d i l u t i o n o r concentration-gradient c a l i b r a t i o n procedures f o r FI-AAS have continued (291, C2421, C2436).and a method based on peak width has been described (846). On t h e basis o f t h e s i n g l e w e l l s t i r r e d mixing chamber model, t h e peak-width a t any a n a l y t e concentration i s p r o p o r t i o n a l t o t h e logarithm of a f u n c t i o n o f t h e concentration. Preconcentration methods based on ion-exchange (2154).and solvent e x t r a c t i o n (419) have been adapted t o FI-AAS determinations, and a d e t a i l e d i n v e s t i g a t i o n o f organic solvents as c a r r i e r s o r sample solvents has been reported (686). O f a number o f solvents tested, acetone was t h e best sample solvent and MIBK t h e best c a r r i e r . I n another i n t e r e s t i n g experiment, FI-AAS was combined i n s e r i e s w i t h FI-spectrophotometry t o a l l o w t h e determination o f t o t a l Fe (by AAS) and Fe( 11) (by spectrophotometry) using 1.10-phenanthroline (2550).Amongst t h e more i n t e r e s t i n g a p p l i c a t i o n s , FI-AAS has been used f o r t h e determination of C r i n s t e e l using a FI-standard a d d i t i o n s method (1254), f o r p l a n t and s o i l a n a l y s i s (2361).and f o r c l i n i c a l m a t e r i a l s (1471, C2445). Although t h e r e i s p l e n t y of i n n o v a t i o n i n t h i s f i e l d , r o u t i n e a p p l i c a t i o n i s s t i l l hampered by t h e l a c k of commercially a v a i l a b l e accessories. 1.3.3.3 k t h o d s which f a l l under t h i s heading i n c l u d e t h e Delves cup and t h e loop microsampling method, b u t apart from t h e comparative study mentioned above (263), no new work on these t o p i c s was reported i n t h e past year.The g r a p h i t e capsule atomizer f i r s t reported by Katskov e t a l . i n 1975 (ARAAS, 1975, 5, Ref. 415) has been used t o atomize samples o f s o i l s and sediments f o r t h e determination o f Pb (C1709).Temporal s i g n a l shapes were found t o depend on t h e p o r o s i t y of t h e g r a p h i t e used, t h e wall thickness, capsule temperature, and D i r e c t Micro-sample I n t r o d u c t i o n i n t o t h e FlameAtomization and Excitation 35 t h e chemical form o f the analyte i n t h e sample. P r e c i s i o n and accuracy were evaluated using peak area measurements.D i r e c t sample i n t r o d u c t i o n has a l s o been achieved from t h e c a v i t y o f a rod (768), and w i t h t h e a i d o f microsounds (C384). I n t h e l a t t e r case absolute d e t e c t i o n l i m i t s o f g were obtained using P t o r p y r o l y t i c g r a p h i t e microsounds and e l e c t r o g r a p h i t e o r p y r o l y t i c graph; t e rods.D i r e c t l a s e r a b l a t i o n w i t h a 30 W CW C02-laser i n an air/C6H6 flame has a l s o been used f o r v a p o r i z a t i o n o f samples i n AAS (603). The method was used f o r geological samples and gave a d e t e c t i o n l i m i t f o r Ag o f 0.1 pg g-’, 1.3.3.4 Sample I n t r o d u c t i o n by V o l a t i l i z a t i o n Some novel approaches t o sample v o l a t i l i z a t i o n f o r subsequent t r a n s f e r t o a flame have been described i n 1984.Berndt described two i n t e r e s t i n g p o s s i b i l i t i e s (2248). I n t h e f i r s t , samples such as orchard leaves were mounted on a 10 mm x 8 mm g r a p h i t e p l a t e and b u r n t i n a stream o f a i r w i t h t h e a i d o f focussed i n f r a r e d lamps.The elements v o l a t i l i z e d (Ag, As, B i , Cd, Hg, Pb, Se. Te, T1, and Zn) were c a r r i e d by the a i r stream d i r e c t l y i n t o t h e mixing chamber o f t h e AAS instrument. A Pb d e t e c t i o n l i m i t o f 2 pg g-’ i n orchard leaves o r 20 ng absolute was achieved. I n t h e second procedure, s o l u t i o n samples o f 5 - 40 ~1 were v o l a t i l i z e d from an e l e c t r i c a l l y heated tungsten loop and t r a n s f e r r e d t o t h e flame v i a t h e mixing chamber by an A r c a r r i e r gas stream.S e n s i t i v i t i e s were approximately 10 times b e t t e r than by conventional AAS measurements. D i s c r e t e i n j e c t i o n o f 111 volumes o f sample s o l u t i o n s i n t o an a i r - c a r r i e r gas stream has a l s o been attempted (1023).The AAS s i g n a l s obtained were stronger and sharper than FI-AAS s i g n a l s due t o improved nebul i z a t i o n / a t o m i z a t i o n c h a r a c t e r i s t i c s , and the a i r - c a r r i e r method i s extremely r a p i d a l l o w i n g t h e o r e t i c a l sample i n t r o d u c t i o n r a t e s o f up t o 600 sampl es h-’.The i n t e r e s t i n g and valuable review by Kantor, h i g h l i g h t e d i n ARAAS l a s t year (1275; see ARAAS, 1933, 2, 32), should be read by any research worker i n t e r e s t e d i n t h e development o f combined systems, i n which v a p o r i z a t i o n i s separated from atomization and e x c i t a t i o n . A1 1 combined methods were c l a s s i f i e d and t h e i r advantages and l i m i t a t i o n s characterized.One o f t h e advantages o f combined methods i s t h e p o s s i b i l i t y o f studying t h e v o l a t i l i z a t i o n processes t h a t occur i n ETA. A t y p i c a l example o f t h i s t y p e o f study concerns t h e i n v e s t i g a t i o n o f the atomization o f Cd compounds i n t h e presence o f MgC12 and ascorbic a c i d (2317).Useful reviews o f coupled chromatography-atomic absorption procedures have been given (652, C2413). T r i f l u o r o a c e t y l a c e t o n e complexes o f Be and Cu have been determined by GC-AAS p r o v i d i n g s o l u t i o n d e t e c t i o n l i m i t s o f 0.022 and 0.003 ug m1-l r e s p e c t i v e l y (C373). A new GC-AAS i n t e r f a c e has been described36 Analytical Atomic Spectroscopy (2413).E f f l u e n t from t h e GC column i s passed through a glass-lined heated i n t e r f a c e , mixed w i t h H2 introduced via a T-piece, and introduced i n t o a conventional air/C2H2 flame. A small H2 flame burns a t r i g h t angles t o the air/C2H2 flame, and t h e atoms are swept i n t o a ceramic tube held i n t h e air/C2H2 flame above t h e sample introduction/H2 flame p o s i t i o n .Detection l i m i t s as low as 17 pg o f Pb as t e t r a a l k y l l e a d were reported. Two HPLC-AAS i n t e r f a c e s have a l s o been reported by Ebdon e t a l . (C2413, (2474). One used d i s c r e t e sample n e b u l i z a t i o n and the s l o t t e d tube atom t r a p , t h e o t h e r was a continuous f l o w hydride generation procedure used f o r As and Sn. 1.3.4 Flame Atomic Fluorescence Spectrometry Most developments i n AFS published i n t h e past year concerned l a s e r e x c i t e d fluorescence and are covered i n Section 1.3.5.1. P u b l i c a t i o n s r e l e v a n t t o t h i s s e c t i o n were few and l i m i t e d t o a review (824, 949). and a new simple method f o r t h e AFS determination o f Pb i n n a t u r a l water samples (1862).A Zeeman-effect s c a t t e r - c o r r e c t i o n system was described f o r non-dispersive AFS (1799). The magnetic f i e l d was a p p l i e d t o t h e atomization c e l l i n a d i r e c t i o n transverse t o t h e source and d e t e c t i o n beams. Both p o l a r i z e d and field-modulated Zeernan e f f e c t s were examined, t h e l a t t e r being p a r t i c u l a r l y s u i t e d t o multi-element AFS.Both procedures gave accurate r e s u l t s f o r t h e AFS a n a l y s i s o f t h r e e NBS reference samples. 1.3.5 Appl i c a t i o n s o f Lasers A c t i v i t y concerning t h e a p p l i c a t i o n o f l a s e r s i n a n a l y t i c a l procedures and f o r d i a g n o s t i c purposes continues t o increase, t h e l a t t e r even reaching t h e pages o f The Times o f London i n 1984 (1).I"1ost p u b l i c a t i o n s f a l l n a t u r a l l y i n t o the usual t h r e e sub-divisions used f o r t h i s section, b u t a r t i c l e s on t h e use o f a l a s e r i n AAS appear t o be s i g n i f i c a n t l y d i f f e r e n t .A frequency modulated l a s e r was used f o r t h e AAS d e t e c t i o n o f Ma i n an air/C2H2 flame Absorbances as low as 1.5 x could be detected w i t h a SNR o f 1, and w i t h multi-passing, a d e t e c t i o n l i m i t o f 3.3 x 10 Na atoms ~ 3 1 1 1 ~ ~ was obtained. A saturated atomic absorption method has a l s o been used f o r s p a t i a l d i a g n o s t i c i n v e s t i g a t i o n s i n an air/C2H2 flame (97). T h i s method has a l s o been used i n I C P d i a g n o s t i c s t u d i e s (see Section 1.2.1.1).( 2 2 5 ) . 6 Other reference o f i n t e r e s t - S e n s i t i v i t y o f frequency modulated absorption spectroscopy w i t h a pulsed dye-laser: 1406. 1.3.5.1 Laser Excited Atomic Fluorescence Spectrometry (LAFS) Increasingly, l a b o r a t o r i e s around t h e world are beginning t o i n v e s t i g a t e the p o t e n t i a l o f laser-excited atomic fluorescence spectrometry w i t h d i f f e r e n t formsA to miza tion and Ex cita ti0 n 37 of atom c e l l , i n c l u d i n g flames, ETA, I C P and t h e DCP.The research groups l e d by Omenetto and Rossi i n I t a l y (C1611) and M i c h e l i n Connecticut (C2425) have achieved much i n t h e p a s t y e a r and have added a s i g n i f i c a n t c o n t r i b u t i o n t o t h a t o f t h e more e s t a b l i s h e d groups i n t h i s f i e l d . Although t h e use o f non-resonance f l u o r e s c e n c e (10, 2264) remains a p o p u l a r method f o r r e d u c i n g t h e problems o f l i g h t s c a t t e r i n t e r f e r e n c e i n LAFS, new methods a r e r e g u l a r l y introduced, and a r e v i e w o f t h i s s u b j e c t c i t e d 94 references (442).One new method d e s c r i b e d i n t h e p a s t y e a r i s based on t h e use o f a l i n e a r l y p o l a r i z e d CW dye-laser (1817). Owing t o t h e h i g h p o l a r i z a t i o n o f t h e s c a t t e r e d l i g h t , i n s e r t i o n o f a p o l a r i z e r i n t h e d e t e c t i o n o p t i c s a l l o w e d e f f e c t i v e r e j e c t i o n o f t h e s c a t t e r i n t e r f e r e n c e .The d e t e c t i o n o f Na i n an air/C2H2 flame, i n t h e presence o f A l , was improved by 460 and 200 i n SNR and SBR, r e s p e c t i v e l y , by t h i s technique. Another new approach t o s c a t t e r c o r r e c t i o n i s p r o v i d e d by l a s e r induced i n t e r m o d u l a t e d flame f l u o r e s c e n c e (1827).I n t h i s procedure, two l a s e r beams, a m p l i t u d e modulated a t d i f f e r e n t frequencies, fl and f2, and counterpropagated c o l i n e a r l y through an atomizer, a r e tuned t o t h e a b s o r p t i o n t r a n s i t i o n o f t h e element of i n t e r e s t .Non-linear m i x i n g o f t h e f l u o r e s c e n c e s i g n a l s occurs owing t o s a t u r a t i o n e f f e c t s . By e x t r a c t i o n o f t h e s i g n a l a t t h e sum o r d i f f e r e n c e frequency, fl f f2, t h e l i n e a r s c a t t e r i n g component o f t h e spectrum can be e s s e n t i a l l y e l i m i n a t e d .The method was demonstrated u s i n g Na i n an Ar/02/HZ flame. C o n s i d e r a t i o n s which i n f l u e n c e t h e c h o i c e o f a t o m i z e r i n LAFS have been c a r e f u l l y e v a l u a t e d by Omenetto and Human (2262). I f u l t i m a t e s e n s i t i v i t y i s r e q u i r e d , ETA i s t h e obvious c h o i c e s i n c e s c a t t e r i n g i s reduced t o a minimum, s o l i d sampling i s p o s s i b l e , and sample d i l u t i o n i s minimized compared t o flames and plasmas.However, even f o r flames and plasmas, e x c e l l e n t r e s u l t s may be achieved p r o v i d e d t h a t (i) t h e l a s e r system a l l o w s adequate s p e c t r a l coverage i n t h e u.v.; (ii) s a t u r a t i o n o f t h e f l u o r e s c e n c e s i g n a l can be approached over a l a r g e sample volume; (iii) t h e gated d e t e c t i o n parameters and t h e l a s e r r e p e t i t i o n frequency a r e o p t i m i z e d t o reach t h e maximum SNR.The a u t h o r s g e n e r a l l y p r e f e r r e d plasmas t o flames because o f t h e w i d e r range o f elements t h a t c o u l d be measured i n plasmas.T h i s paper c o n t a i n s a c l e a r l y presented fundamental d i s c u s s i o n o f t h e a n a l y t i c a l p o t e n t i a l o f LAFS and should be read by anyone i n t e r e s t e d i n t h i s s u b j e c t . D e s p i t e t h e s e n e g a t i v e comments, a number o f new a p p l i c a t i o n s o f flames i n LAFS measurements have been r e p o r t e d (C1075, C1234, C1675, C1730, 1786. 1861, 2264). The d e t e c t i o n l i m i t s f o r Pb and T1 o f 0.02 and 0.8 ng m1-l achieved i n a separated air/C2H2flarne (2264) have allowed t h e development o f s i m p l e methods f o r t h e d e t e r m i n a t i o n o f these elements i n b i o l o g i c a l m a t e r i a l s (C1730, 1861). In b o t h cases non-resonance f l u o r e s c e n c e was used t o reduce i n t e r f e r e n c e from l i g h t s c a t t e r .Laser induced i o n i c fluorescence has been used f o r t h e38 Analytical A tomic Spectroscopy determination o f Ba i n a N20/C2H2 flame w i t h a d e t e c t i o n l i m i t o f 0.7 ng m l - ' (1736). The l i n e a r c a l i b r a t i o n curve f o r t h e flame LAFS determination o f Ca a t 422.6 nm has been extended from 0.05 ng mil- t o 500 ug m l - 1 by o p t i m i z a t i o n o f t h e design of t h e dynode chain of the IP28 PMT used (C1075).The advantages o f a pulsed Cu-vapour laser-pumped dye-laser operated a t a 5 KHz r e p e t i t i o n r a t e have been demonstrated using AFS measurements i n an air/C2H2 flame (C1234). The h i g h r e p e t i t i o n r a t e leads t o more e f f i c i e n t photon use, and a r e d u c t i o n i n t h e time r e q u i r e d t o reach a given SNR, as w e l l as b e t t e r pulse r e p r o d u c i b i l i t y .Some authors have again reported t h e use o f electrothermal atomization i n LAFS (166, C1675, 1756, (2425). A microcomputer c o n t r o l l e d g r a p h i t e r o d LAFS system produced d e t e c t i o n l i m i t s f o r Mn, Na, and Sn o f 20, 3, and 5 pg r e s p e c t i v e l y (1756).The instrumental c o n f i g u r a t i o n s r e q u i r e d f o r t h e development o f a Zeeman background c o r r e c t i o n system f o r furnace LAFS have been evaluated ((2425). The uses o f both d i r e c t c u r r e n t plasmas (C1076) and i n d u c t i v e l y coupled plasmas (10, C269, C273, C1073, C1425, C1611, 2262, 2264) have received considerable a t t e n t i o n as atom c e l l s f o r LAFS i n 1984, although a l l b u t one o f t h e I C P papers (C1073) i s derived from t h e I s p r a group o f Omenetto and Rossi.As reported p r e v i o u s l y (ARAAS, 1983, 13, Ref. C2293). use o f an excimer-pumped dye-laser and an A r - I C P provided d e t e c t i o n l i m i t s between 0.4 and 20 ng m1-I f o r a range o f 14 elements (10, 2264).Useful i n f o r m a t i o n on t h e measurement o f i n d i v i d u a l elements has now been given, and t h e advantages and disadvantages o f t h i s system were c a r e f u l l y evaluated (2264). The s i n g l e element character o f the technique represents a disadvantage compared t o some a l t e r n a t i v e methods, but introduces t h e major advantages o f s p e c t r a l s e l e c t i v i t y and s e n s i t i v i t y .A novel experiment i n ICP-LAFS concerned t h e use o f an I C P modulated a t frequencies between 100 and 600 Hz (C1073). The p r o p e r t i e s o f t h e modulated-ICP were i n v e s t i g a t e d by LAFS, and showed t h a t a t 60% modulation depth, t h e LAFS s i g n a l i s delayed w i t h respect t o t h e modulation waveform. The delay time i s independent o f t h e modulation frequency b u t increases w i t h increase i n I C P observation height.Two groups have reported t h e LAFS d e t e c t i o n o f 0 atoms i n flames (C1235, 2568). A fuel-lean air/C2H2 flame was used i n one case (2568). and a N2/N20/CH4 i n t h e o t h e r (C1235), but both groups u t i l i z e d t h e two photon resonant e x c i t a t i o n a t 225.6 nm, and t h e t r i p l e t fluorescence a t 844.7 nm, and t h e c o l l i s i o n a l l y induced q u i n t e t fluorescence a t 777.5 nm. Detection o f C and H atoms by s i m i l a r methods has a l s o been reported (C1235).The advantages o f fluorescence f o r combustion diagnostics, p a r t i c u l a r l y t h e r m a l l y a s s i s t e d fluorescence o f e x t e r n a l l y introduced seeds o r i n t e r n a l species such as OH, has been stressed by Winefordner (2157).S i m i l a r conclusions were deduced by H i e f t j e e t a l . w i t h respect t o t h e i n v e s t i g a t i o n o f t h e s p a t i a l diaRnostics o f flameAtomization and Excitation 39 t h e I C P (C1909).Other references o f i n t e r e s t - AFS determination o f Cs; 2055. Measurement o f o p t i c a l l y t h i c k atomic vapours by non-linear l e a s t squares f i t t i n g o f absorption o r fluorescence spectra: 2204. Tunable dye-lasers w i t h optoacoustic f i l t e r s as a source i n AFS: 1461. 1.3.5.2 Laser Enhanced I o n i z a t i o n (LEI) I n t e r e s t i n LEI i s now extending across t h e world w i t h recent r e p o r t s o f i n t e r e s t i n g experiments c a r r i e d o u t i n China, Poland, Russia, and Sweden.Three u s e f u l reviews appeared, two on t h e p r i n c i p l e s o f LEI (554, 2278), and t h e o t h e r concerned w i t h t h e general use o f optogalvanic d e t e c t i o n (551).A s u b s t a n t i a l number o f a p p l i c a t i o n s papers have appeared d u r i n g t h e past year, most o f them r e l a t i n g t o flame atomization (554, 600, 612, 613, C1204, C1205, 2323). The l a s e r enhanced i o n i z a t i o n o f Zn, which has an i o n i z a t i o n p o t e n t i a l o f 9.4 eV, has been described using e x c i t a t i o n schemes based on both t h e 213.8 and 307.6 nm resonance l i n e s (1205).Multiphoton optogalvanic spectroscopy has a l s o been used f o r t h e d e t e c t i o n o f H and 0 r a d i c a l s i n flames (540). Novel developments i n atom c e l l s f o r LEI have included the use o f electrothermal atomization (413, 613). an i n d u c t i v e l y coupled plasma (C1207). a microarc plasma (C1203), and a low pressure discharge (C1714).Ytterbium was detected a f t e r atomization a t 2500 K i n an e l e c t r i c a l l y heated Ta-lined g r a p h i t e furnace a t low pressure (413). Stepwise i o n i z a t i o n o f Yb was achieved using r a d i a t i o n from two N -laser-pumped tunable dye-lasers operated a t 555.6 and 452.8 nm. Signals were detected by a secondary-electron m u l t i p l i e r and gave a SNR o f 200 f o r 1 ng o f Yb.An extended t o r c h was used f o r t h e I C P studies, which were d i f i c u l t owing t o t h e h i g h concentration o f charged species i n t h e plasma i t s e l f (C1207). Only t h e t a i l - f l a m e r e g i o n could be investigated, &, 19 mm above t h e load c o i l , and d e t e c t i o n o f Cu, Fe, Mn and Na was poor. 2 Several research groups have continued t o i n v e s t i g a t e t h e theory of o p t i m i z a t i o n o f flame LEI. Green e t a l . p o i n t e d o u t t h a t t h e L E I s i g n a l i n conventional flames may be adversely a f f e c t e d by multiphoton i o n i z a t i o n o f t h e solvent (C1203). The r e l a t i v e m e r i t s o f sample desolvation processes based on solvent s t r i p p i n g , a g r a p h i t e furnace, and microarc v a p o r i z a t i o n were evaluated.The same group has again emphasized t h e advantages t o be derived from using a t o t a l consumption burner f o r LEI (598, 1260). Detection l i m i t s f o r Cu and I n are improved (x5) compared t o a conventional pre-mixed burner.Improvements i n d e t e c t i o n power have a l s o been achieved by decreasing t h e e l e c t r o n i c noise using c a r e f u l separation o f t h e l a s e r from t h e s i g n a l r e g i s t r a t i o n apparatus, and by enclosing t h e burner w i t h t h e ion-detecting probe i n a welded copper container having o n l y small openings f o r t h e l a s e r beams and gas l i n e s (2381).Two40 Analytical Atomic Spectroscopy t h e o r e t i c a l models have been described t o e x p l a i n t h e LEI process and s i g n a l generation (559, 611). A p o i n t charge model based on charge i n d u c t i o n theory was used t o p r e d i c t t h e motion o f the charged species produced by LEI, and t o c a l c u l a t e t h e magnitude and shape o f t h e LEI c u r r e n t pulse (559).The theory gave e x c e l l e n t agreement w i t h observed e l e c t r o n and i o n s i g n a l pulses, and also a c c u r a t e l y p r e d i c t e d observed a l k a l i metal i n t e r f e r e n c e e f f e c t s , and t h e e f f e c t o f l a s e r beam p o s i t i o n . An i n t e r e s t i n g r e p o r t has described t h e use o f microwave d e t e c t i o n o f LEI s i g n a l s (599).The main advantage i s t h a t the microwave f i e l d can be kept a t such a low l e v e l t h a t t h e k i n e t i c s o f combustion o f the flame are n o t disturbed. Optogalvanic measurements i n hollow cathode lamps have a l s o received some i n t e r e s t i n t h e past year (552, 1404, 1758). The most i n t e r e s t i n g a p p l i c a t i o n was t h e determination o f 63Cu/65Cu i s o t o p i c r a t i o s i n human blood based on measurements o f h y p e r f i n e atomic s p e c t r a l s t r u c t u r e , and h i g h r e s o l u t i o n optogalvanic spectroscopy (1785).The samples were electrodeposited on the cathode of a demountable HCL and e x c i t e d by a tunable CW dye-laser, t h e HCL serving as both t h e atomization source and detector.The optogalvanic spectra o f Th and U i n HCLs provided convenient l i n e s f o r dye-laser wavenumber c a l i b r a t i o n w i t h an accuracy o f a few p a r t s i n 10 (1404). 8 1.3.5.3 Other Studies A new technique which uses s p u t t e r i n g t o v o l a t i l i z e s o l i d samples f o r resonance i o n i z a t i o n spectroscopy has been described (2067, 2097). The method i s termed " s p u t t e r i n i t i a t e d resonance i o n i z a t i o n spectroscopy" o r S I R I S , and has been suggested as a p o s s i b l e method f o r t h e determination o f Pu, Th, and U i n b i o l o g i c a l samples (2067).Analysis o f U i n u r i n e can be achieved a t l e v e l s down t o 0.05 LIE 1-1 a t reasonable c o s t and good accuracy. Apparently a p r e l i m i n a r y chemical separation i s required. A l l elements except He and Ne can be determined by S I R I S w i t h r o u t i n e s e n s i t i v i t i e s down t o 1 p a r t i n 10". Electrothermal atomization has again been used i n an i n t r a c a v i t y atomic absorption procedure f o r t h e determination o f Eu, Sm, Tm and Y (649). The d e t e c t i o n l i m i t s achieved are n o t encouraging, being i n t h e 3.3 - 10 mg m1-I range f o r a l l elements except Eu, which gave 0.01 mg m1-I. An I C P has now been used f o r i n t r a c a v i t y AAS measurements (C1167). Two dye-1 asers, one flashlamp-pumped one CW, were i n v e s t i g a t e d w i t h > l o 2 and > l o 4 enhancements over t h e r e s p e c t i v e e x t r a c a v i t y AAS measurements. and The use o f a range o f l a s e r techniques f o r t h e study o f molecules and r a d i c a l s f o r d i a g n o s t i c purposes i n flames has received much emphasis i n t h e past year. Coherent anti-Stokes Raman s c a t t e r i n g (CARS) remains a popular method (13, C1505, 1766), as does l a s e r induced molecular fluorescence (1, C1505, C1506, 1766). I n t h e l a t t e r , use was made o f a p l a n a r sheet o fA toinization and Excitation 41 r a d i a t i o n w i t h d e t e c t i o n based on an image i n t e n s i f i e r , t o produce two-dimensional p i c t u r e s o f r a d i c a l s i n flames which were displayed immediately i n t h e form o f coloured v i d e o p i c t u r e s (1, C1505, C1506). Resonance enhanced m u l t i p l e photon i o n i z a t i o n (REMPI) has a l s o been used f o r t h e study o f flame r a d i c a l s Several o f these r a d i c a l s a r e d i f f i c u l t t o d e t e c t by any o t h e r means. Pulsed-laser e x c i t a t i o n o f C02, NH2 and OH has been detected o p t o a c o u s t i c a l l y i n flames (12). T h i s i s more s e n s i t i v e than a r e Raman methods and does n o t s u f f e r from t h e c o l l i s i o n a l quenching o f fluorescence which i s a severe problem i n h i g h pressure environments. Photothermal l a s e r d e f l e c t i o n spectroscopy has been used f o r t h e measurement o f t h e OH d i s t r i b u t i o n i n a premixed air/C3H8 flame T h i s technique i s non-perturbing and possesses b o t h s p a t i a l and temporal r e s o l u t i o n . An optoacoustic d e f l e c t i o n technique was used t o o b t a i n t h e temperature p r o f i l e s . such as C, C20, CH, CH3, CO, H, NO and 0 (C1206, C1505). (2567).

ISSN:0306-1353    

DOI:10.1039/AA9841400026

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

A toinization and Excitation 41 1.4 ELECTROTHERMAL ATOMIZATION Without doubt t h e most s i g n i f i c a n t p u b l i c a t i o n i n t h i s f i e l d d u r i n g t h e year was t h e s p e c i a l e d i t i o n o f Spectrochimica Acta dedicated t o Professor B.V. L'vov. T h i s e x c e l l e n t c o l l a t i o n o f a r t i c l e s i n c l u d e d b o t h a t r a n s l a t i o n o f L ' v o v ' s o r i g i n a l paper on ETA (905) as w e l l as a d e t a i l e d account o f h i s s c i e n t i f i c c a r e e r (1243).The e n t i r e e d i t i o n must be regarded as e s s e n t i a l reading f o r a l l workers i n t h i s f i e l d , covering as i t does n o t o n l y h i s t o r i c a l overviews o f t h e technique by S l a v i n (1242) and L l v o v h i m s e l f (1244).b u t a l s o many o t h e r e x c e l l e n t s t a t e - o f - t h e - a r t a r t i c l e s encompassing a l l o f t h e i m p o r t a n t areas i n ETA development. Reviews o f many o f these a r t i c l e s a r e i n c l u d e d i n t h i s s e c t i o n o f ARAAS; however, readers a r e urged t o a c q u i r e t h e o r i g i n a l e d i t i o n , which w i l l undoubtedly become a landmark i n ETA. 1.4.1 Fundamental Processes 1.4.1.1 Mechanistic Studies The l i m i t a t i o n o f L'vov p l a t f o r m s a r e now being w e l l categorized. It i s apparent t h a t d e s p i t e t h e i r u t i l i t y as a simple approximation t o i s o t h e r m a l atomization, t h e compromize h e a t i n g c o n d i t i o n s employed may. i n some instances, cause a n a l y t i c a l problems.F a l k (C1420) e s t a b l i s h e d t h a t a p e r i o d o f about one second was r e q u i r e d i n t h e a t o m i z a t i o n c y c l e b e f o r e temporal and s p a t i a l e q u i l i b r i a were achieved. T h i s l a g t i m e was shown by Sienier e t a l . (1005) t o be s u f f i c i e n t f o r premature l o s s o f a n a l y t e vapour', and t h a t t o approach isothermal a t o m i z a t i o n c o n d i t i o n s , m a t r i x m o d i f i e r s were necessary f o r v o l a t i l e42 Analytical Atomic Spectroscopy elements.A t h e o r e t i c a l model was proposed by Chakrabarti e t a l . (903) which demonstrated how t h e vapour phase temperatures experienced by atoms o f such elements were much h i g h e r than would be expected i n conventional w a l l atomization.W h i l s t t h i s i s h a r d l y a new conclusion, t h e authors f u r t h e r established t h a t premature l o s s o f analyte vapour i s a serious l i m i t a t i o n t o p l a t f o r m atomization. The importance o f h e a t i n g r a t e on peak-height measurements i n both isothermal and non-isothermal atomizers was emphasized by Frech e t a l .(829). W h i l s t t h e evaporation c h a r a c t e r i s t i c s o f t h e element o f i n t e r e s t were o f course c r i t i c a l , i t was heating r a t e which was o f prime importance. The usefulness o f s i g n a l i n t e g r a t i o n has been debated by S p e r l i n g (238; see a l s o ARAAS, 1983, 13, Ref. 711) and S l a v i n (237).The l a t t e r believes t h a t t h e d i s p e r s a l o f t h e atomic cloud by t h e expanding i n e r t gas plays a dominant r o l e i n d e f i n i n g the atomization s i g n a l and hence absorbance measurements should be time based. The importance o f oxygen i n t h e mechanism o f atomization i s now being f u l l y appreciated. There appear however t o be inconsistencies i n t h e l e v e l s o f p a r t i a l pressure a c t u a l l y measured.Sturgeon e t a l . (828) used a s e n s i t i v e chemiluminescence r e a c t i o n employing P vapour t o measure 0 p a r t i a l pressure. Oxygen was claimed t o be present a t l e v e l s many orders o f magnitude higher than would be expected by t h e reaction: 2 2c + o2 $ 2co 6 Measured O2 concentrations were 10 g r e a t e r than those c a l c u l a t e d by Frech and co-workers (see ARAAS, 1980, 3, Ref. 478) who attempted t o i n v e s t i g a t e t h i s discrepancy.They temperature range concentration o f O2 atomizer s u b s t r a t e values were i n p a r t elements are known (C1693) showed t h a t Te, were degraded oxides. concluded t h a t t h e p a r t i a l pressure o f O2 decreased over t h e 1500 - 2500 K from lo-’’ t o lo-” atm.The i n i t i a l was dependent n o t o n l y on t h e m a t r i x b u t a l s o on t h e and i t s geometry. Hence t h e discrepancies i n absolute due t o d i f f e r e n c e s between t h e systems employed. Several t o be very s e n s i t i v e t o 0 p a r t i a l pressure. Sedykh e t a l .t h e atomization o f As, Sb, and Sn, and t o a l e s s e r e x t e n t i n t h e presence o f 0 owing t o t h e formation o f gaseous 2 2 The use o f complementary techniques as a i d s t o t h e e l u c i d a t i o n o f atomization mechanisms i s an i n t e r e s t i n g by-product o f p r a c t i c a l ETA. The i n f o r m a t i o n obtained, f o r example from mass spectrometric studies, however elegant, may be c r i t i c i z e d as n o t being r e p r e s e n t a t i v e o f atomization a t atmospheric pressure.The pressure ranges o f conventional mass spectrometers are o f course f a r removed from those employed i n r o u t i n e ETA. S t y r i s and Kaye (C1210, C1422) appreciated t h i s and hence used a d i f f e r e n t i a l pressure system t oA tomization and Excitation 43 a l l o w sampling o f vapour generated a t atmospheric pressure.However, Holcombe e t a l . (C1209. C1419, C1424) used an atomizer o p e r a t i n g under reduced pressure f o r s i m i l a r studies. W h i l s t t h e species which they i d e n t i f i e d may w e l l be genuine intermediates i n t h e atomization o f Se, more d e f i n i t i v e i n f o r m a t i o n can o n l y come from a re-configured sampling system, a f a c t conceded by t h e authors.Not q u i t e so c o n t r o v e r s i a l , b u t e q u a l l y adventurous was the use8 o f FT-i.r. techniques t o study molecular species t h a t occur i n t h e atomization process. T i t t a r e l l i e t a l . (C1169, 1836) studied t h e atomization o f s o l i d pigments using t h i s approach.The speed o f data a c q u i s i t i o n was l i m i t e d by t h e r e l a t i v e l y slow scan time (0.5 s ) i n t h e instrument used. A study o f atomization peak shapes o f t e n leads t o d e t a i l e d i n f o r m a t i o n regarding competing r e a c t i o n s i n t h e g r a p h i t e furnace. Sturgeon (C1211, C1601) noted a temperature s h i f t o f AA s i g n a l s i n response t o changes i n O2 p a r t i a l pressure. pulse was found t o be o f prime importance.Harnly (C1538) appreciated t h e importance o f t h e i n f o r m a t i o n which can be derived from peak shapes i n d e f i n i n g optimum c o n d i t i o n s f o r p r a c t i c a l analyses. The r o l e o f t h e atomization surface i n c o n t r o l l i n g t h e s i g n a l A study o f emission s p e c t r a l l i n e p r o f i l e s by Marshall e t a l .( 7 9 5 ) was used t o e x p l a i n t h e causes o f c a l i b r a t i o n graph curvature i n g r a p h i t e furnace AE. A t low concentrations self-absorption was t h e major influence, w h i l s t a t l e v e l s 100 times t h e d e t e c t i o n l i m i t s e l f - r e v e r s a l became t h e dominant process.C a l i b r a t i o n graph curvature i n Zeeman AA was studied by de Loos-Vollebregt and de Galan (1463). It was shown t h a t beyond t h e absorption maxima, t h e slope was dependent on the remaining absorption a t maximum f i e l d strength. Hence t h e absorbance a t t h e " r o l l - o v e r ' ' p o i n t can be estimated.I t was claimed t h a t the use o f an a.c. Zeeman system can extend t h e dynamic range by a l l o w i n g a combination o f maximum f i e l d w i t h intermediate ( r a t h e r than zero) f i e l d , and hence reducing maximum absorbance. A t t h e intermediate f i e l d , absorbance readings are taken j u s t o f f the l i n e centre, so s e n s i t i v i t y i s reduced and c a l i b r a t i o n curves are extended. 1.4.1.2 Interference Studies Despite t h e g r e a t e r understanding o f the processes involved i n producing atomic vapour i n electrothermal atomizers, some p r a c t i c a l problem areas s t i l l p e r s i s t .Isothermal atomization via p l a t f o r m o r probe technology has l e d t o a r e d u c t i o n i n the occurrence and magnitude o f vapour-phase interferences.However, Welz e t a l . (C1122, C1433, C2435) have demonstrated t h a t some l o s s o f analyte as v o l a t i l e h a l i d e can s t i l l occur when using a p l a t f o r m atomizer. Using a p l a t f o r m w i t h two sample c a v i t i e s , one c o n t a i n i n g analyte and the other m a t r i x i n t e r f e r a n t , reduced s i g n a l s f o r Cu, Pb, and Sb were observed when NiC12 was t h e matrix.Vapour-phase c h l o r i d e i n t e r f e r e n c e on Mn. Pb. and T1 was a l s o observed44 Analytical Atomic Spectroscopy by S l a v i n e t a l . (558) u s i n g a s i m i l a r system. The use o f p y r o l y t i c g r a p h i t e o r g l a s s y carbon p l a t f o r m s should, t h e y i n f e r r e d r a t h e r than proved, f u r t h e r reduce t h e magnitude o f such e f f e c t s by m i n i m i z i n g i n t e r c a l a t i o n o f h a l i d e i n t h e g r a p h i t e s t r u c t u r e .More s u b t l e i n t e r f e r e n c e e f f e c t s have r e c e n t l y been recorded. R i l e y (812) has discussed t h e e f f e c t s o f A1 on t h e d e t e r m i n a t i o n o f As.It has been a p p r e c i a t e d f o r some t i m e t h a t problems e x i s t when u s i n g t h e As 193.7 nm l i n e due t o o v e r l a p o f a nearby A111 l i n e . However, u s i n g Haynes d i g e s t procedure f o r d e t e r m i n i n g As i n c o a l (see ARAAS, 8, Ref. 569 and 1982, 12, Ref. 1545). t h e A1 i s prevented from i n t e r f e r i n g by p r e c i p i t a t i o n as MgA1F5.xH20.The i n f l u e n c e o f valency s t a t e on t h e a t o m i z a t i o n o f Se, when s t a b i l i z e d w i t h n i c k e l , i s important. W h i l s t Se(V1) i s e f f e c t i v e l y r e t a i n e d on t h e atomizer up t o 1000 "C, Se(1V) may be l o s t a t temperatures above 500 "C. However, Se(1V) i s s t a b i l i z e d i n t h e presence o f n i c k e l up t o temperatures o f approximately 1000 "C.The c r i t i c a l n a t u r e o f temperature/time programmes i s t h e r e f o r e worth s t r e s s i n g (848). Magnesium n i t r a t e was found t o be a more e f f e c t i v e m o d i f i e r t h a n was n i c k e l . 1.4.2 Atomizer Design W h i l s t t h e concept o f i s o t h e r m a l a t o m i z a t i o n has l e d t o a c e r t a i n u n i f o r m i t y i n atomizer geometry, c o n s i d e r a b l e e f f o r t i s s t i l l b e i n g d i r e c t e d towards improvements i n atomizer s u b s t r a t e .B a s i c a l l y , t h e e l e c t r o t h e r m a l atomizer can be regarded as a degradeable r e s i s t i v e element i n t h e o u t p u t c i r c u i t o f a power supply.Consequently, any a l t e r a t i o n i n t h e performance o f t h a t element w i l l have a marked e f f e c t on t h e a n a l y t i c a l measurement. The range o f m a t e r i a l s and t h e p h y s i c a l parameters which i n f l u e n c e a n a l y t i c a l performance have been discussed by P r i c e and Whiteside (C1690) and a l s o by V o e l l k o p f (C1545).De Galan and de Loos-Vollebregt (907) have spent some t i m e examining t h e p o t e n t i a l v a l u e o f a new t y p e o f g l a s s y carbon. T h i s m a t e r i a l showed a h i g h r e s i s t a n c e t o o x i d a t i v e a t t a c k , produced low blank l e v e l s and c o u l d w i t h s t a n d temperatures t o 3200 K. However, t h e "constant s e n s i t i v i t y " , p r e v i o u s l y r e p o r t e d f o r t h i s m a t e r i a l , has n o t i n p r a c t i c e been r e a l i z e d a t h i g h temperatures.The p r o p e r t i e s o f g l a s s y carbon have a l s o been shown (C1541) t o be o f importance when s t u d y i n g a t o m i z a t i o n mechanisms. The r e l a t i v e l y i n e r t glassy-carbon s u r f a c e was t h o u g h t t o be l e s s e f f e c t i v e t h a n p y r o l y t i c g r a p h i t e f o r solid-phase r e d u c t i o n o f metal oxides. Hence, i n some cases, improved a t o m i z a t i o n e f f i c i e n c i e s would be expected w i t h t h e l a t t e r m a t e r i a l .The use o f t o t a l l y p y r o l y t i c - g r a p h i t e tubes has been p r e v i o u s l y advocated (see ARAAS, 1983, 2, 39).Many c l a i m s about t h e i r performance have been made: f o r example, Dymott and Whiteside (C2442) have claimed a r e d u c t i o n i n vapour-phase i n t e r f e r e n c e s . However, a more r i g o r o u s a n a l y t i c a l e v a l u a t i o n was c a r r i e d o u t by L i t t l e j o h n andAtomization und Excitation 45 colleagues (1459), using Mn, Pb, and V as test elements, over a range of atomization temperatures.Repeated measurements of temperature and sensitivity were made until the cuvette was destroyed. This work verified the extended life-time and relatively constant sensitivity of pyrolytic graphite tubes over normal electrographite tubes for practical analyses. Studies by Chakrabarti - al. (2254) of the temperature gradients of three tubular pyrolytic-graphite furnaces, having different configurations of lamellar planes, showed differences in these temperature gradients during capacitative heating owing to conductivity differences in the various planes within the graphite structure.Some minor, though nevertheless important, modifications to furnace geometries have been reported. Responding to previous criticisms of poor sample-volume capacity.Carnrick and Lumas (1883) have proposed a modified design of the standard L'vov platform. This design can accept up to 80 ~1 of sample, which is more than sufficient for most practical purposes and approximately doubles the absolute sensitivity. Other criticisms often levelled at platform atomization techniques are the degraded precision and inconvenience.To overcome these, Pfeil et al. have described a one-piece cuvette which provides delayed atomization of sample into a preheated absorption cell. Should this design prove acceptable it may have more analytical potential than the platform (see also Section 1.4.1.1). Another more radical approach to isothermal atomization has been proposed by Sperling (901).This consists of a "tube-in-tube" atomizer whereby a smaller graphite tube is inserted in the ordinary tube causing a delay in atomization and thereby approximating isothermal atomization conditions. For the volatile elements studied, this device produced significant increases in sensitivity over wall or platform atomization. A comparison of the sensitivity of this device with conventional furnace designs was made by Magyar et al.(765). The former was found to be more sensitive by a factor of 3 - 6. A new pyrometric-temperature feedback control system which covers the entire working temperature range was described by Herber et al. (906). A single i.r. detector was used with an independent feedback circuit for each of three heating ranges.Improvements in precision for difficult determinations such as Pb in blood and Cd in urine were demonstrated. A theoretical discussion of pyrometric temperature control was presented by Fa1 k (1249). The systematic errors in using narrow-band pyrometers were calculated for different tube lengths. The operational wavelengths, it was claimed, should be as short as possible for the temperatures of interest. 1.4.3 Sample Introduction It i s significant that one of the major growth areas in applied analytical research in ETA is in the use of probe atomization. T h i s concept, derived from46 Analytical A tomic Spectroscopy L ' v o v ' s o r i g i n a l work on isothermal atomization, has proved t o be t h e simplest p r a c t i c a l approximation t o constant-temperature atomization.The optimum design c o n f i g u r a t i o n s f o r a probe system have been characterized by L i t t l e j o h n e t a l . (769) using a modified commercial atomizer. The most important parameters were found t o be t h e tube diameter and t h e q u a l i t y o f t h e g r a p h i t e used f o r both tube and probe. The same authors have a l s o automated the probe sample i n t r o d u c t i o n system (C2437, C2558) (see a l s o ARAAS, 1983, 12, 43) and have i d e n t i f i e d t h e advantages and disadvantages o f t h e system w i t h reference t o d e t e c t i o n l i m i t s , tube l i f e t i m e and t h e analysis o f r e a l samples, The major advantage of t h e probe over t h e p l a t f o r m mode o f atomization i s i t s lack o f dependence on temperature optimization. This was seen by C a r r o l l e t a l .((2463) as an advantage f o r simultaneous multi-element analysis where compromise c o n d i t i o n s must, o f necessity, be used. A comparison o f probe and p l a t f o r m modes o f atomization was presented by Chakrabarti e t a l . (C1191, C1432, 1768). Although both systems were found t o be comparable when t h e l a t t e r was optimized, t h e use o f elevated atomization temperatures caused premature l o s s o f analyte vapour from v o l a t i l e elements i n the p l a t f o r m furnace (see a l s o Section 1.4.1.1).The probe device was, however, much more t o l e r a n t o f h i g h atomization temperatures, an advantage when determining v o l a t i l e elements i n complex matrices r e q u i r i n g vigorous ashing procedures.Nethods f o r t h e i n t r o d u c t i o n and analysis o f s o l i d samples have n o t r e a l l y progressed s i g n i f i c a n t l y , d e s p i t e t h e considerable advantages t o be gained from d i r e c t analysis. This year again saw a v a r i e t y o f novel a l t e r n a t i v e s which show some promise as p r a c t i c a l a n a l y t i c a l devices.An obvious area o f research comes o f course from t h e use o f probe type devices (C334, C1542). Those described were e s s e n t i a l l y g r a p h i t e sample cups which were r a i s e d i n t o t h e preheated furnace. Despite t h e elegance o f t h i s approach, t h e p r e c i s i o n of t h e technique was o n l y about lo%, probably mainly a t t r i b u t a b l e t o sampling v a r i a t i o n s .A furnace c o n f i g u r a t i o n designed s p e c i f i c a l l y f o r s o l i d samples was described by Falk and Schmidt (C1678). Again t h e sample cup p r i n c i p l e was used, although no d e t a i l s o f a n a l y t i c a l performance were given. An i n t e r e s t i n g device f o r determining Cd and Zn i n samples o f s o l i d t i n was described by Takeda and Hirokawa (2247).A g r a p h i t e cup w i t h a l i d was used t o enclose t h e Cd o r Zn vapour. Using coherent forward s c a t t e r i n g as t h e method o f analysis, a high i n t e n s i t y s i g n a l was obtained from t h e analyte w h i l s t the i n f l u e n c e o f the m a t r i x was minimized.Concentrations as low as 1 ng g-' o f Cd could be determined. A method o f sampling airborne p a r t i c u l a t e s was described by Papp (1252), i n which porous g r a p h i t e tubes were used as a i r f i l t e r s . A f t e r c o l l e c t i o n , the tubes were heated t o 3700 K and t h e a n a l y t e emission was measured on a spectrograph. Obviously t h i s type o f simple handling system i s i d e a l l y s u i t e d f o r p a r t i c u l a t e analysis, i n which complex sample-collectionAtomization and Excitation 47 systems often i n v a l i d a t e r e s u l t s due t o h i g h blanks.It w i l l be i n t e r e s t i n g t o see i f t h i s i s adapted f o r furnace probe work. The use o f a ruby l a s e r t o a b l a t e samples i n a preheated atomizer was discussed by Wennrich and D i t t r i c h (303, C1698, 2314; see a l s o Section 1.1.2).Unfortunately, t h e a n a l y t i c a l r e s u l t s were s t r o n g l y m a t r i x dependent. Other references o f i n t e r e s t - Trace elements i n semiconductor materials, w i t h s o l i d sample i n troduc t i on: C2470. 1.4.4 Developments i n Techniques Arguably the most i n n o v a t i v e work c u r r e n t l y being undertaken i n t h e f i e l d o f ETA i s i n the development o f t h e Furnace Atomization Non-thermal E x c i t a t i o n Spectrometry (FANES) (see ARAAS, 1982, 12, Ref. 425). Atomization and e x c i t a t i o n c o n d i t i o n s i n FANES are very d i f f e r e n t from those i n a conventional furnace.The use o f low gas pressures decrease t h e atom vapour residence time, w h i l s t t h e t u b u l a r furnace provides a low-pressure discharge f o r o f t h e atomic vapour (C1443). This c o n f i g u r a t i o n has r e s u l t e d i n s i g n i f i c a n t l y lower d e t e c t i o n l i m i t s being achieved compared t o ICP-OES o r ETA-AAS (831). The technique has been a p p l i e d t o low-level determinations i n h i g h - p u r i t y acids (2599) and i n aluminium (C1623).The p o t e n t i a l o f FANES as a v i a b l e a n a l y t i c a l t o o l f o r t r a c e multi-element analyses i s s u b s t a n t i a l . Comparisons between the more complex FANES source and t h e simpler ETA-AES w i t h probe atomization have been made by Ottaway e t a l .(C351, 1035). and it w i l l be i n t e r e s t i n g t o f o l l o w t h e progress o f both these techniques over t h e next few years. e x c i t a t i o n The moves towards t h e use o f ETA-AAS as a multi-element t o o l have been progressing f o r some years. y e t so f a r no commercially v i a b l e instrument has appeared. The reasons f o r t h i s are not c l e a r , b u t may w e l l be based on commercial r a t h e r than performance grounds.Harnly e t a l . (774) have discussed i n d e t a i l t h e c u r r e n t s t a t u s o f continuum-source AAS w i t h respect t o measurement mode, atomization c o n f i g u r a t i o n ( w a l l o r p l a t f o r m ) and temperature programme. The o p t i m i z a t i o n o f these parameters f o r multi-element a n a l y s i s (478, C1449) produced d e t e c t i o n l i m i t s comparable w i t h line-source AAS f o r elements w i t h wavelengths above 280 nm.Such c o n d i t i o n s y i e l d e d t y p i c a l accuracies and p r e c i s i o n s o f +I0 - 15% i n t h e 10 - 120 ng m l - It i s p o s s i b l e t h a t t h e b e n e f i t s o f t h e probe system f o r multi-element analysis, described by C a r r o l l & a l .(C2463) could be f u r t h e r i n v e s t i g a t e d i n t h i s context (see a l s o Section 1.4.3). 1 range. Background c o r r e c t i o n has always been a r a t h e r c o n t r o v e r s i a l t o p i c since the i n c e p t i o n o f ETA. There now e x i s t s a v a r i e t y o f high-performance systems designed t o cope w i t h t h e problems o f matrix-background absorption.A comparison of t h e Zeeman e f f e c t w i t h other methods o f background c o r r e c t i o n was48 Analytical A tomic Spectroscopy made by S l a v i n and C a r n r i c k (C1434). De Galan and de Loos-Vollebregt (C1435) s t a t e d t h a t commercial background-correction systems were a compromize between a n a l y t i c a l s e n s i t i v i t y , wavelength p r o x i m i t y , and " r o l l - o v e r l ' o f t h e working curves.An a l t e r n a t i v e c o r r e c t i o n system i s t h a t o f r e p e t i t i v e scanning o r wavelength modulation. Marshall e t a l . (C409, C1555, C2440) have discussed t h e m e r i t s o f t h i s technique, which i s e q u a l l y a p p l i c a b l e t o both continuum-source a b s o r p t i o n and emission modes o f operation. A v a r i a t i o n i n t h e wavelength modulation technique i s t h e use o f a sectored-wheel square-wave system (1816).which measures background a t two wavelengths adjacent t o t h e a n a l y t e wavelength r a t h e r t h a n from a wavelength scan. Detection l i m i t improvements o f two orders o f magnitude were observed i n ETA-AAS, considerably enhancing t h e a n a l y t i c a l p o t e n t i a l o f t h e technique.A n a l y t i c a l molecular a b s o r p t i o n measurements i n furnaces have been t r e a t e d w i t h some scepticism. However, r e c e n t work by D i t t r i c h e t a l . (285, 912, 913, 1462) and a l s o by workers i n Japan (1248) has demonstrated t h e p r a c t i c a l f e a s i b i l i t y o f t h e technique f o r determining h a l i d e s and S by measuring t h e s p e c t r a o f d i a t o m i c molecules o r i g i n a t i n g i n t h e g r a p h i t e furnace.The determination o f these elements i n s i l v e r bromide, semiconductor m a t e r i a l s and d a i r y produce has been demonstrated, b u t c u r r e n t problems w i t h t h e o p t i m i z a t i o n o f t h e thermal programme r e q u i r e f u r t h e r i n v e s t i g a t i o n . A f a s c i n a t i n g and unusual a p p l i c a t i o n has been r e p o r t e d by Batz e t a l . (1801). The d i f f e r e n t i s o t o p i c e f f e c t s o c c u r r i n g i n o p t i c a l s p e c t r a were discussed and a method was presented f o r determining t h e d i s t r i b u t i o n s o f s t a b l e isotopes. The method, based on Zeeman scanning a t an a b s o r p t i o n l i n e i n an evacuated furnace, c o u l d d i s t i n g u i s h between samples o f d i f f e r e n t i s o t o p i c contents even under sub-optimal c o n d i t i o n s . A second concept t h a t has i t s r o o t s i n i n o r g a n i c MS i s t h a t o f standardless analysis. S l a v i n and C a r n r i c k (830, 1035) have s t a t e d t h a t w i t h i n c e r t a i n l i m i t s , t h e absorbance values o b t a i n a b l e from an optimized p l a t f o r m furnace a r e reasonably constant and independent o f m a t r i x . Hence s e m i - q u a n t i t a t i v e a n a l y s i s w i t h o u t t h e use of standards should be f e a s i b l e . T h i s hypothesis was t e s t e d on t h e analyses o f v a r i o u s reference m a t e r i a l s and accuracies o f 10 - 20% were achieved. T h i s concept i s worth pursuing i n more d e t a i l , although c u r r e n t l i m i t a t i o n s on atomizers may r e t a r d f u r t h e r progress.

ISSN:0306-1353    

DOI:10.1039/AA9841400041

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

48 Analytical A tomic Spectroscopy 1.5 VAPOUR GENERATION The t e c h n i q u e o f vapour g e n e r a t i o n has been e x p l o i t e d b y a n a l y s t s f o r many y e a r s and one m i g h t expect t h a t n o t much new m a t e r i a l would be forthcoming. However,Atomization and Excitation 49 w h i l s t t h e number o f new development papers has decreased, t h e l e v e l o f s o p h i s t i c a t i o n has increased. 1.5.1 H y d r i d e Generation I n a p r e v i o u s volume o f ARAAS, t h e e x c e l l e n t m e c h a n i s t i c s t u d i e s o f Welz and Melcher (see ARAAS, 1983, 13, 46) were reviewed. A t t h e t i m e t h e s e stood as t h e benchmark i n o u r understanding o f t h e processes i n v o l v e d i n h y d r i d e generation. The same a u t h o r s have c o n t i n u e d by demonstrating how t h e presence o f hydrogen r a d i c a l s i s e s s e n t i a l f o r e f f i c i e n t decomposition o f h y d r i d e s a t t h e low temperatures used i n quartz-tube furnaces (C1123, C1421).I n t h e i r experiments, generated h y d r i d e s were c o l l e c t e d i n a c o l d t r a p p r i o r t o t r a n s f e r t o a heated q u a r t z tube.It was found t h a t t h e h y d r i d e s d i d n o t e f f i c i e n t l y decompose u n l e s s H was i n t r o d u c e d i n t o t h e system. Hydrogen produced by BH4- r e d u c t i o n , b e i n g d i s c o n t i n u o u s , was found t o be i n s u f f i c i e n t f o r complete atomization. The d i f f i c u l t i e s i n v o l v e d i n t r y i n g t o e f f e c t t h e e f f i c i e n t a t o m i z a t i o n of h y d r i d e s i n a q u a r t z tube a t 1000 "C were discussed by D i t t r i c h and Mandry (C375).The low temperature, t h e y concluded, favoured t h e f o r m a t i o n o f small a n a l y t e m a t r i x molecules which m i g h t be r e l a t i v e l y s t a b l e a t 1000 "C. A t o m i z a t i o n i n a g r a p h i t e f u r n a c e a t 2700 " C a f t e r h y d r i d e g e n e r a t i o n y i e l d e d an almost 100-fold improvement i n d e t e c t i o n l i m i t s , and a marked r e d u c t i o n i n i n t e r f e r e n c e s a t t r i b u t a b l e t o molecule formation.I n a f u r t h e r s e r i e s o f papers, Welz and Melcher (2331, 2332, 2333) discussed i n d e t a i l a v a r i e t y o f i m p o r t a n t i n t e r f e r e n c e s on t h e h y d r i d e g e n e r a t i o n o f As and Se.The d e l e t e r i o u s e f f e c t o f t r a n s i t i o n metals on Se d e t e r m i n a t i o n was found t o be c o n t r o l l a b l e by a d j u s t i n g t h e a c i d s t r e n g t h , w h i l s t t h e i n t e r f e r e n c e o f N i on As c o u l d be a l l e v i a t e d by t h e a d d i t i o n o f F e ( I I 1 ) due t o p r e f e r e n t i a l r e d u c t i o n o f F e ( I I 1 ) t o F e ( I I ) , which i n h i b i t e d t h e p r e c i p i t a t i o n o f i n t e r f e r i n g N i as t h e metal.T r a n s i t i o n - m e t a l i n t e r f e r e n c e s on As were a t t r i b u t e d t o k i n e t i c e f f e c t s .The same a u t h o r s determined Se i n human body f l u i d s (C2443) and showed how t h e t y p e of a c i d and t h e a c i d s t r e n g t h a f f e c t e d r e s u l t s . 2 The c u r r e n t t r e n d towards h i g h sample throughput has been i l l u s t r a t e d i n t h e d e s c r i p t i o n o f automated d e v i c e s f o r h y d r i d e generation. I n one, Brown g - a l .(C1510, C1674) used a twin-channel p e r i s t a l t i c pump t o t r a n s p o r t b o t h sample and r e d u c t a n t t o a r e a c t i o n vessel, p r i o r t o a t o m i z a t i o n o f t h e h y d r i d e s i n a q u a r t z tube. A s i m i l a r accessory was d e s c r i b e d by Schrader and Sturman (C1514) which employed a more complex g a s - l i q u i d separator.I n b o t h systems t h e continuous s i g n a l allowed use o f l o n g e r i n t e g r a t i o n t i m e s and hence improved p r e c i s i o n . A complex automated system d e s c r i b e d by Narasaki and I k e d a (1840) was termed a b a t c h F I system, a l t h o u g h t h i s appears t o be a misnomer. I t employed a s o p h i s t i c a t e d v a l v e arrangement t o c o n t r o l t h e sequence of f l o w s i n t h e stream.Both As and Se were determined i n biological and r i v e r - w a t e r50 Analytical Atomic Spectroscopy samples. The use o f hydride generation i n s p e c i a t i o n studies continues t o be o f i n t e r e s t i n many d i v e r s e f i e l d s . A combination o f HPLC-hydride generation-ICP was used by Bushee and co-workers (821) t o determine As anions.The r e s u l t s demonstrated t h a t t h e technique was capable o f q u a n t i t a t i v e s p e c i a t i o n o f arsenate and a r s e n i t e a t l e v e l s above 50 ug 1-' i n n a t u r a l waters. Hambrick fi - a l . (702) achieved d i f f e r e n t i a t i o n between Ge species: methylated germanium species were p r e f e r e n t i a l l y trapped out o f t h e r e a c t i o n stream ( i n preference t o GeH4) and then released i n t o a g r a p h i t e furnace operated a t 2700 "C.Determination o f both o x i d a t i o n s t a t e s o f Te was demonstrated by Andreae (1843). A f t e r preconcentration o f t h e Te onto Mg(OH)2 t h e Te species [Te(IV) then Te(VI)] were removed by c o l d a c i d e x t r a c t i o n , and determined by hydride generation w i t h ETA.An i n t e r e s t i n g , i f somewhat incomplete, d e s c r i p t i o n o f t h e determination o f I n and Te by hydride generation was presented by Yau e t a l . (288). Although optimized c o n d i t i o n s are described, t h e p r a c t i c a l u t i l i t y o f t h e system f o r r e a l samples i s uncertain.A comparison o f B i H generation by using NaBH powder and s o l u t i o n r e d u c t i o n was described (785). The s o l u t i o n method y i e l d e d an order o f magnitude lower d e t e c t i o n l i m i t . Some workers show g r e a t persistence i n attempts t o determine Pb by hydride generation. Enriques e t a l . (C1148) c l a i m t o have a successful combination o f reagents which can y i e l d accurate Pb determination i n NBS orchard leaves and water and c l a i m i t t o be a p p l i c a b l e t o a wide v a r i e t y o f o t h e r samples "provided c e r t a i n i n t e r f e r e n c e s can be eliminated". A 3 4 very i n t e r e s t i n g d e s c r i p t i o n o f a hydride generation method coupled t o a He-glow discharge as a d e t e c t o r was given by Matsumoto (927).Once e l e c t r o d e gap, gas f l o w r a t e and power had been optimized f o r t h e glow discharge, d e t e c t i o n l i m i t s from 0.1 - 6 ng o f most hydride forming elements could be achieved. 1.5.2 Mercury Determination Developments i n t h e use o f cold-vapour generation techniques f o r t h e determination of Hg have over t h e l a s t few years been f a i r l y i n s i g n i f i c a n t .Very l i t t l e m a t e r i a l i s c u r r e n t l y being produced which could be regarded as i n n o v a t i v e i n terms o f technique development, although many users w i l l r e a l i z e t h a t a knowledge gap s t i l l e x i s t s i n t h e realm o f sample handling. Two examples o f i n t e g r a t e d Hg-determination instruments are worthy o f review t h i s year.I n t h e f i r s t , Puschel and co-workers (1739) described a microcomputer-controlled instrument c o n t a i n i n g thermal and o x i d a t i v e furnaces leading t o t w i n absorption c e l l s . I n t h i s instrument, gases, l i q u i d s and s o l i d s could be analysed and such v e r s a t i l i t y seems a p o s i t i v e step forward i nAtomization and Excitation 5 1 Hg determination. An automated system based on F I was described by M o r i t a & - a l . (482). Samples o f 64 u l were i n j e c t e d i n t o a f l o w i n g a c i d stream, which was mixed downstream w i t h SnC12 reductant. The Hg was determined by non-dispersive AFS using a s o l a r - b l i n d PMT. Throughputs o f 35 samples h-l could be achieved and a d e t e c t i o n l i m i t of 0.008 ng was daimed. Such systems based on F I o f f e r considerable promise.

ISSN:0306-1353    

DOI:10.1039/AA9841400048

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

CHAPTER 2 Instrumentation 2.1 LIGHT SOURCES Only a few s i g n i f i c a n t p u b l i c a t i o n s on l i g h t sources appeared i n 1984. A m a g n e t i c a l l y c o n f i n e d lamp (C1552) was d e s c r i b e d f o r a p p l i c a t i o n i n AAS, AFS. and t u n a b l e atomic l i n e molecular spectroscopy. The magnetic p o l e gap, an i n t e g r a l p a r t o f t h e lamp, was o n l y a few mm wide and f i e l d s t r e n g t h s o f o v e r 10 kG were p r o v i d e d by r e l a t i v e l y small permanent magnets.The lamp was operated w i t h an Ar gas f l o w , and t h e combined e f f e c t s o f a p u l s e d d.c. e l e c t r i c f i e l d ( 5 - 50 kHz) and t h e magnetic f i e l d caused s p u t t e r i n g t o occur i n a small r e g i o n approaching a p o i n t source.The s p u t t e r e d atoms were e x c i t e d i n t h e r.f. d i s c h a r g e t o produce sharp s p e c t r a l l i n e s o f h i g h i n t e n s i t y . The atoms were c o n t a i n e d i n t h e d i s c h a r g e r e g i o n by a boron n i t r i d e s h e l l which minimized s e l f - a b s o r p t i o n e f f e c t s s i n c e c o m p a r a t i v e l y few u n e x c i t e d atoms e x i s t e d i n t h e l i g h t path.The o u t p u t wavelength o f t h e lamp c o u l d be v a r i e d c o n t i n u o u s l y by changing t h e s t r e n g t h o f t h e magnetic f i e l d . The o n l y l i m i t a t i o n on t h e wavelength range was t h e magnetic f i e l d s t r e n g t h . The authors claimed t h a t t h e wavelength t u n i n g f l e x i b i l i t y c o u l d be enhanced i f t h e d i s c h a r g e was viewed p a r a l l e l t o t h e f i e l d d i r e c t i o n .A wide c h o i c e o f s p e c t r a l l i n e s was made a v a i l a b l e by p l a c i n g d i f f e r e n t elements i n t h e h o l l o w cathode o f t h e lamp. I n a d d i t i o n t o t h e above c h a r a c t e r i s t i c s , i t was r e p o r t e d t h a t t h e lamp was h i g h l y s t a b l e .A new s e l f - s c a n n i n g h i g h - r e s o l u t i o n l a s e r source based on phase conjugated o p t i c s has been developed (C1182). Phase c o n j u g a t i o n i n v o l v e s t h e use o f n o n - l i n e a r o p t i c a l techniques t o phase-reverse an e l e c t r o m a g n e t i c wave and produce an e x a c t l y counter-propagating wave.A barium t i t a n a t e c r y s t a l , which can generate a phase-conjugate s i g n a l w i t h a r e f l e c t i v i t y as h i g h as 60% a t v i s i b l e wavelengths, was placed i n f r o n t o f a broadband CW dye l a s e r . The r e s u l t a n t phase-conjugate s i g n a l was t r a n s m i t t e d back i n t o t h e o s c i l l a t o r t o produce o u t p u t r a d i a t i o n w i t h a bandwidth reduced t o 0.05 8.The n a t u r e o f t h e feedback c o n d i t i o n s r e s u l t e d i n t h e p r o d u c t i o n o f a r e p e t i t i v e monotonic scan o f t h e o u t p u t wavelength o v e r a 250 kl range. The authors r e p o r t e d t h a t t h i s s e l f - s c a n n i n g h i g h - r e s o l u t i o n l a s e r source can be used t o make Doppler-free atomic s p e c t r o s c o p i c measurements o f s i n g l e photon t r a n s i t i o n s .The a n a l y t i c a l c h a r a c t e r i s t i c s o f thermal g r a d i e n t lamps (TGL) have been 5354 Analytical Atomic Spectroscopy investigated (167, 517) and compared with those of EDLs. Flame AFS (167) detection limits obtained for Cd (0.5 1-1g 1-’) and Se (100 1-18 1- ) using TGLs were within a factor of 7 and 3 respectively of the best values obtained with microwave-excited EDLs.The stability o f the TGLs was significantly better than that of the EDLs. An AAS study (517) revealed that for As and Se, the resonance lines from the TGLs were more intense and narrower than those from EDLs. 1 A demountable cathode lamp arrangement (C1500) was developed to allow the determination of both P and S by AAS and AFS at wavelengths of 177.49 and 180.74 nm, respectively.Other references of interest - H.f modulation of resonance radiation sources: 772, 957. ICP as an emission source for ICP-AFS: C1077. Patent for an AAS HCL: 797. Review on the development of hollow cathode emission sources: 1068. 2.2 OPTICAL SYSTEMS AND DETECTORS 2.2.1 Optics The growing interest in high resolution spectrometers for ICP-OES analysis was illustrated by the number of papers that described the application and characteristics of echelle grating monochromators (C35, C124, C348, C1185, C1202, 1269, C1303, C1342, C1575, C1908, C1923, 2257, 2258, 2259). A 1.5 m echelle monochromator with predisperser (C1303, 2257, 2258, 2259) was used to measure the physical half-widths of ICP lines.and to investigate the contribution made by the wings o f the line profiles to the background intensity. From the study, it was argued that a spectrometer with a resolving power of 50 000 - 70 000 in the U.V. region and 60 000 - 100 000 in the visible region could be used for the measurement of line-rich spectra.However, the authors suggested (2257) that resolving powers o f up to twice these values would be required ideally. A similar investigation (2260), conducted with a 1 m monochromator equipped with a 3600 1 ines mm-’ holographic grating, concluded that a resolving power o f 150 000 was necessary in ICP-OES to approach the physical line-width (see also Section 1.2.1.3).A new echelle spectrometer based on crossed dispersion (C348) has been developed that is capable of wavelength selection in less than 1 s (see also Section 2.7.1). A photographic attachment was designed for the Beckman Spectraspan I11 echelle spectrometer (1269) that was interchangeable with the PMT cassette assembly. A theoretical comparison of monochromators used for wavelength-modulation continuum-source atomic absorption spectrometry and atomic emission spectro-Instrumentation 5 5 metry has been conducted (322).A study of the effect of monochromator parameters on the detection limits achieved by both techniques revealed that the ideal monochromator should possess a short focal length, a high angular dispersion, a large grating area, and a large slit height.It was shown that for continuum-source AAS, high and medium resolution monochromators should give the best detection limits, whereas for AES, medium or low resolution monochromators are satisfactory. The latter conclusion has been confirmed experimentally (C351). The manufacture and characteristics o f blazed holographic gratings used in medium and low resolution monochromators have been discussed (C44, C50).The resolution and efficiency of a holographic grating were shown to be similar to those of an equivalent ruled grating, but the stray light performance of the holographic grating was an order of magnitude better. A high resolution Fourier transform (FT) spectrometer based on a folded Michelson interferometer (236, 1819) was used to make spectral measurements that allowed calculation of the FeI excitation temperature in an ICP. The system was also used to identify Ar lines in the near-i.r.region (C1426). The FT measurements of the near-i.r. ICP lines of C, H, and S (679) have also been reported. A piezo-electrically scanned Fabry-Perot interferometer system was developed allow measurement of the low-intensity hyperfine structure of the Cd 479.92 nm transition (1412).to The optics and detection system of an ARL 33000 Analyser were modified (320) to convert the instrument from a sequential to a multichannel direct-reading spectrometer, thereby reducing the time taken to determine a large number of elements. Improvements i n the flexibility and speed of analysis by ICP-OES were achieved (C1586) through the development o f a polychromator which had several exit sl it/detector assemblies that could be moved to various positions around the Rowland circle.On a similar topic, additional information was provided by Strasheim et al. (11) on the design o f internal optical systems developed to improve the versatility of a Rowland-mount spectrometer (see ARAAS, 1983, 13, Refs. 1035, C2004). A method for the repositioning o f exit slits in multichannel spectrometers was also described by the same group (1806). An oscillating quartz refractor plate was used to monitor and correct wavelength drift encountered during operation of a polychromator (C1181). Installation of motor-driven exit slit shutters (C114) in a direct reading spectrometer reduced the stray light caused by the intense illumination o f adjacent channels.Other references of interest - Measurement of stray light in FAAS: C1557. Monochromator wavelength accuracy and reproducibility: 1778. Patent for optical system of an AA spectrometer: 206. Selective-1 ine modulation: 722.56 Analytical Atomic Spectroscopy Spectrometer-based system for aeroso Vapour-phase FT-i .r.studies with an partic ETA dev e size measurements: 591. ce: C1169. 2.2.2 Detectors Although the sensitivity and SNR characteristics of photodiodes are inferior in the U.V. and visible wavelength regions in comparison with PMTs, photodiode array detectors have many useful applications in atomic spectroscopy. Plultiple photodiode arrays were used with a direct-reading spectrometer (C1907) to provide, in part, an electronic spectral measurement facility analogous in wavelength coverage to a photographic plate.Similarly, a 1024-channel photodiode array detector (C1362) was mounted horizontally in the exit focal plane of a 0.35 rn monochromator to allow simultaneous measurement of a number of spectral lines emitted by a DCP. Intensities were obtained for 400 separate spatial positions across the DCP discharge, and the information used to construct spectral maps of analyte intensity, electron density, and excitation temperature.Photodiode array detectors were used in ICP studies to measure the spectra of non-metals (557) and alkali metals (C1197). The most intense lines of these elements are at near-i.r. wavelengths, the region of maximum sensitivity for photodiode detectors.In ETA-AAS. photodiode array detectors have been used to extend the linear calibration range (763), and for the measurement of molecular and atomic spectra in the wavelength range 190 - 355 nm ( C1104). A critical comparison of intensified self-scanning photodiode arrays and silicon intensified target (SIT) vidicons as radiation detectors for ICP-OES was reported (566).The operational characteristics included in the comparison were detector noise, linearity, spectral resolution, wavelength coverage, and the ability to perform spectral stripping and interpolative correction o f variable background components. The practical advantages and limitations of SIT vidicons for various applications in atomic spectrometry (444) were evaluated by a consideration o f detector characteristics such as two-dimensional image fidelity, temporal resolution and gating, and channel-to-channel and pixel-to-pixel response as a function of position on the detector. A charge-injection detector (CID) television camera system was reported (476) for use in simultaneous multi-element analysis by OES.Operational procedures to reduce noise, increase dynamic range, and reduce pixel cross-tal k were discussed.The authors claimed that the detection limits achieved with the CID were equivalent to or better than those obtained with PMT detectors. The virtues of photographic detection procedures in multi-element OES analysis were re-iterated by a number of authors. It was found that photographic emulsions were distinctly better for detection of trace elements, in comparison with PNTs, if the measurement time was not excessive (see alsoInstrumentation 57 Section 1.1.1).It has been suggested (967) that photographic detector systems that incorporate a computer-controlled microdensitometer have advantages over photoelectric detectors, since a permanent record of the spectrum is provided, pre-selection of wavelength channels is not required, and the correct identification of emission lines is more easily achieved.A semi-automatic procedure for the evaluation o f spectrographic plates (485) was developed to assist analysis of silicate rocks and minerals by d.c. arc-OES. Other references of interest - Application of optogalvanic detection i n atomic spectrometry: 551, 1788 (see also Section 1.3.5.2).Image dissecting detector for ICP diagnostic studies: 157. Improvement in calibration linearity near the detection limit in laser-excited AFS by use of a gated PMT: C1075 (see also Section 1.3.5.1 ). Silicon photodetector for FAES: 2379. Variable filter for smoothing of noisy spectra: 1844. 2.3 BACKGROUND CORRECTION A line reversal procedure similar to the Smith-Hieftje background correction procedure (see ARAAS, 1982, 12, 45) was proposed by Siemer (713) for application in AAS.A single short duration high-current HCL power pulse (s, 170 us, 280 mA) was used per measurement cycle. Radiation from the lamp was measured at the beginning and end o f each current pulse after Lorentz line-broadening and self-reversal had time to develop fully.The difference between the absorbance signals during the two sampling periods was found to be unaffected by continuum absorption or line-scattering. It was claimed that the single pulse approach had all the features of the Snith-Hieftje system, but with the additional advantage that all radiation measurements were made when the HCL emission was very intense in comparison with the signal from extraneous light sources (*, flame or electrothermal atomizer).The same author warned (891) that although the Smith-Hieftje system avoided the beam misalignment problems of dual-source background correction methods, variations in the mean position of the light-emitting species in the HCL caused slight spectral non-coincidence when the lamp was operated at low and then high currents. Under- and over-correction of background absorption could therefore occur.The background correction capabilities of the Srnith-Hieftje system have been described by workers from Allied Analytical Systems (C48, C1436) in comparison with dual source (849, C1125, C1448) and Zeeman-effect (1467) procedures. Additional independent studies were conducted (C1435, C1609, 1803) which compared the observed58 Analytical Atomic Spectroscopy advantages and l i m i t a t i o n s o f these t h r e e instrumental background c o r r e c t i o n methods. It was suggested (C1435, 1803) t h a t the performance o f each procedure was e s s e n t i a l l y a compromise between loss i n a n a l y t i c a l s e n s i t i v i t y , r o l l - o v e r o f t h e c a l i b r a t i o n curve, and the p r o x i m i t y o f t h e background c o r r e c t i o n wavelength. The Zeeman-effect system achieves good s e n s i t i v i t y and wavelength proximity, b u t i s l i m i t e d by c a l i b r a t i o n r o l l - o v e r (C1463).A r o l l - o v e r phenomenon has also been observed w i t h t h e Smith-Hieftje method, but t h e e f f e c t can be reduced if a n a l y t i c a l s e n s i t i v i t y and wavelength p r o x i m i t y c h a r a c t e r i s t i c s a r e s a c r i f i c e d .R e l a t i v e l y few fundamental AAS studies o f Zeeman-effect background c o r r e c t i o n were reported i n 1984. It i s known t h a t when e i t h e r a r o t a t i n g p o l a r i z e r and s t a t i c magnetic f i e l d , o r a modulated magnetic f i e l d , i s used, t h e r e i s a time l a g between the measurements o f t h e reference and sample signals.To achieve t r u l y simultaneous Zeeman-effect background c o r r e c t i o n (C1558) a Wollaston-type p o l a r i z e r and a s t a t i c magnetic f i e l d have been used (see a l s o ARAAS, 1977, 1, Ref. 1388). The basis o f the procedure was mentioned i n a previous paper by t h e authors (see ARAAS, 1976, 6, Ref. 816). The system has now been optimized and applied i n AAS analysis. Further studies o f t h e shapes o f a n a l y t i c a l c a l i b r a t i o n graphs i n Zeeman-effect AAS (1463) have revealed t h a t beyond t h e absorption maximum, the slope o f t h e graph depends on t h e remaining absorption a t maximum f i e l d strength.A method f o r c a l c u l a t i n g t h e absorbance and concentration a t t h e r o l l - o v e r p o i n t was described, and i t was shown t h a t use o f an a.c. Zeeman system extends t h e dynamic range o f t h e c a l i b r a t i o n graph, although s e n s i t i v i t y i s impaired s l i g h t l y .Zeeman-effect ETA-AAS procedures were reported f o r the determination o f Cd i n u r i n e (265), Se i n u r i n e (684) and human t i s s u e (C14). Pb i n blood plasma (218), Cu and Zn i n mononuclear c e l l s and n e u t r o p h i l s (C1120). and Ag (618) and o t h e r elements (C1121) i n marine samples. A Zeeman-effect FAAS method was developed f o r measurement o f As (437), and an ETA-AAS procedure was developed f o r t h e d i r e c t determination o f t r a c e elements i n s o l i d s placed on a g r a p h i t e p l a t f o r m (C1125).Numerous papers were presented by workers from the Perkin-Elmer Corporation d e s c r i b i n g t h e advantages o f a.c. Zeeman-effect background c o r r e c t i o n operated i n conjunction w i t h p l a t f o r m atomization procedures (C370, 847, 850, C1124, C1134, C1250, 1775, 1878, 1890; see a l s o Section 1.4.4.2).The Zeeman scanning o f absorption l i n e s o f atoms produced i n a furnace a t low pressure (1801) has been used f o r s t a b l e isotope analysis by AAS. Although i t was p o s s i b l e t o d i s t i n g u i s h between samples w i t h d i f f e r e n t i s o t o p i c contents, t h e optimum operating c o n d i t i o n s f o r t h e instrument have s t i l l t o be established.Zeeman-effect background c o r r e c t i o n procedures f o r atomic fluorescence spectrometry have been i n v e s t i g a t e d (1799). A transverse magnetic f i e l d was a p p l i e d t o t h e atomization c e l l , and a comparison made o f p o l a r i z e d Zeeman andInstrumentation 59 f i e l d modulated Zeeman procedures.Although b o t h approaches were used s u c c e s s f u l l y t o c o r r e c t f o r t h e s c a t t e r o f source r a d i a t i o n , f i e l d modulated Zeeman-AFS was p r e f e r r e d s i n c e t h e s c a t t e r s i g n a l was unchanged when t h e magnet was on, and t h u s t h e use o f e m p i r i c a l l y determined c o r r e c t i o n f a c t o r s , as a p p l i e d i n t h e p o l a r i z e d Zeeman procedure, was unnecessary.Also, t h e field-modulated f o r m a t was i d e a l l y s u i t e d t o multi-element AFS. The a p p l i c a t i o n o f Zeeman-effect c o r r e c t i o n procedures has a l s o been considered f o r 1 aser-exci t e d AFS (C2425). I n continuum-source AAS, background c o r r e c t i o n i s achieved by wavelength modulation u s i n g a q u a r t z r e f r a c t o r p l a t e .A d d i t i o n a l i n f o r m a t i o n on t h e advantages o f a 5-step m o d u l a t i o n waveform f o r e x t e n s i o n o f c a l i b r a t i o n l i n e a r i t y i n continuum-source AAS (327) has been g i v e n (see ARAAS, 1952, 11, 51).The 5-step waveform allowed s p e c t r a l measurements a t t h e c e n t r e o f a l i n e p r o f i l e , a t wavelengths on e i t h e r s i d e o f t h e l i n e , and a t p o s i t i o n s on t h e wings o f t h e l i n e mid-way between t h e c e n t r e and ends o f t h e modulation i n t e r v a l . Absorbance values c a l c u l a t e d from i n t e n s i t y measurements were used t o c o n s t r u c t 2 separate c a l i b r a t i o n curves.A s i n g l e channel v e r s i o n o f t h i s c o n t i nuum-source AAS i n s t r u m e n t has now been c o n s t r u c t e d (C409, C1555, C2440). An Apple I I e microcomputer was used t o s u p p l y s i n e , square-wave o r 5-step modulation waveforms t o t h e scanner c o n t r o l l e r . The modulated s i g n a l from t h e PMT o u t p u t was passed via a p r e a m p l i f i e r and ADC t o t h e computer (see S e c t i o n 2.5.2).T h i s system was operated w i t h flame and e l e c t r o t h e r m a l atomizers, and c o u l d be used f o r ETA-AES and FAES measurements w i t h t h e a p p r o p r i a t e software. Various ETA procedures have been e v a l u a t e d (C1444) f o r use i n simultaneous multi-element a n a l y s i s by continuum-source AAS, and compromise o p e r a t i n g c o n d i t i o n s were determined f o r p l a t f o r m (478) and probe (C2558) a t o m i z a t i o n .The development and general s t a t u s o f t h e continuum-source AAS t e c h n i q u e were considered i n an a u t h o r i t a t i v e review by O'Haver (526).A d d i t i o n a l i n f o r m a t i o n on t h e a p p l i c a t i o n o f a square-wave wavelength modulation chopper i n ETA-AES (see ARAAS, 1980, 10, Ref. 1233) has been p r o v i d e d (1816). The system enables a c c u r a t e c o r r e c t i o n o f continuum background e m i t t e d by t h e atomizer t u b e and s c a t t e r e d by m a t r i x components. High frequency wavelength m o d u l a t i o n o f I C P emission s p e c t r a was a p p l i e d (C1141, C1428) t o achieve background c o r r e c t i o n o f t r a n s i e n t a n a l y t e s i g n a l s produced by h y d r i d e generation, e l e c t r o t h e r m a l atomization, microsampl e f l o w i n j e c t i o n , and d i r e c t sample i n s e r t i o n devices.The r e p e t i t i v e scanning technique was a p p l i e d s u c c e s s f u l l y t o t h e d e t e r m i n a t i o n o f P i n foods and NBS SRMs.The e x i t s l i t o f a 1 m monochromator was m o d i f i e d (1784) t o p e r m i t off-peak background c o r r e c t i o n i n emission spectrometry. Two small m i r r o r s mounted i n a V-shaped c o n f i g u r a t i o n were p o s i t i o n e d behind t h e e x i t s l i t a d j u s t e d t o a widthAnalytical A toinic Spectroscopy 60 o f ca.s l i t o c e n t r a e i t h e r PMT. 1 mm. The gap between t h e m i r r o r s c o u l d be a l t e r e d t o g i v e a c e n t r a l 10 - 100 pm. Atomic and background r a d i a t i o n passed through t h i s s l i t and was measured by t h e f i r s t PbIT. Background r a d i a t i o n passed on s i d e o f t h e c e n t r a l s l i t and was r e f l e c t e d by t h e m i r r o r s t o a second E l e c t r o n i c s u b t r a c t i o n o f t h e PMT c u r r e n t s was claimed t o p r o v i d e background c o r r e c t i o n w i t h v e r y s h o r t response t i m e s and w i t h o u t l o s s i n SNR.Other r e f e r e n c e s o f i n t e r e s t - Background c o r r e c t i o n by non-dispersive magneto-optic r o t a t i o n : 770.O p t i m i z a t i o n 653. Reduction o f background a b s o r p t i o n through use o f p l a t f o r m C1515. Two wavelength AAS c o r r e c t i o n procedure f o r t h e d e t e r m i n a t i o n o f Cd i n rocks: 674. Use of a furnace alignment j i g t o reduce D - a r c background c o r r e c t i o n e r r o r s i n ETA-AAS: 1838.o f pulsed-HCL c o n d i t i o n s f o r background c o r r e c t i o n i n AAS: a t o m i z a t i o n : 2 2.4 AUTOMATIC SAMPLE INTRODUCTION Computer-controlled sampling systems have been developed f o r ICP-OES. An apparatus which a l l o w s automatic a d d i t i o n o f a d i l u e n t o r o t h e r a d d i t i v e s f o r v a r y i n g t h e c o n c e n t r a t i o n o f a s o l u t i o n i n t r o d u c e d t o an I C P has been described i n a p a t e n t (736).The d e t e r m i n a t i o n o f t r a c e elements i n r o c k s by ICP-OES was achieved a f t e r batchwise ion-exchange s e p a r a t i o n s u s i n g LABROB, a c o m p u t e r - c o n t r o l l e d r o b o t i c sample h a n d l i n g system (C1319).The LABROB system can handle t h r e e s e t s o f 12 samples batchwise and performs a l l o p e r a t i o n s a u t o m a t i c a l l y , i n c l u d i n g t h e f i n a l e l u t i o n o f a n a l y t e elements from t h e ion-exchange columns. A d d i t i o n a l r e f e r e n c e s o f i n t e r e s t on t h e p r e c e d i n g t o p i c - 1455. C1492. The a p p l i c a t i o n o f continuous f l o w systems f o r t h e automatic g e n e r a t i o n o f h y d r i d e s and mercury vapours i n AAS was d e s c r i b e d by workers from Pye Unicam L t d .(C347, C1510, C1674) and V a r i a n Associates L t d . (C1140, C1446, C1514, C2434, C2460) (see a l s o S e c t i o n 1.5.1). The sample and reagent s o l u t i o n s were mixed p r i o r t o r e a c h i n g t h e r e a c t i o n / g a s - l i q u i d s e p a r a t i o n c e l l i n both systems.Continuous f l o w h y d r i d e g e n e r a t i o n procedures have a l s o been a p p l i e d i n t h e d e t e r m i n a t i o n o f As and Se by ICP-OES (C91, 458) and f o r t h e measurement o f t o t a l A s i n foods b y DCP-OES (743). The a n a l y t i c a l c h a r a c t e r i s t i c s o f t h e DCP procedure compared f a v o u r a b l y w i t h those o f two d i f f e r e n t h y d r i d e g e n e r a t i o n AAS methods.A he1 ium glow-discharge d e t e c t o r was developed (927) f o r a p p l i c a t i o n w i t h a continuous f l o w h y d r i d e g e n e r a t i o n system. Vapour p r o d u c t i o n wasInstrumentatiori 61 c o n t r o l l e d t o a l l o w continuous o p e r a t i o n o f t h e d i s c h a r g e throughout t h e r e a c t i o n stage (see a l s o S e c t i o n 1.5.1).An o n - l i n e f l o w - i n j e c t i o n m a n i f o l d , i n c o r p o r a t i n g an i o n exchange column, was a p p l i e d i n t h e d e t e r m i n a t i o n o f P i n s t e e l s by ICP-OES (C1378). Sample s o l u t i o n s were drawn through a microcolumn o f a c t i v a t e d alumina i n t h e i n j e c t i o n v a l v e t o separate phosphate i o n s from t h e Fe m a t r i x .When t h e m a n i f o l d was switched t o t h e o n - l i n e p o s i t i o n , t h e microcolumn acted as a sample loop, and t h e phosphate i o n s were e l u t e d i n t o t h e main c a r r i e r stream by i n j e c t i o n o f a 200 p1 volume o f 1 KOH.The s e p a r a t i o n procedure avoided s p e c t r a l i n t e r f e r e n c e by Fe a t t h e P 213.6 nm wavelength. An automatic i n j e c t i o n and d i l u t i o n system (C126, C1546) was developed which allowed t h e d i r e c t d e t e r m i n a t i o n o f t r a c e m e t a l s i n o i l s by ICP-OES a t a r a t e o f 80 samples h-’.A f l o w i n j e c t i o n c a l i b r a t i o n procedure was developed f o r FAAS (291) t h a t performed continuous d i l u t i o n o f a s i n g l e c o n c e n t r a t e d standard s o l u t i o n . T h i s s o l u t i o n was i n t r o d u c e d by a r o t a r y i n j e c t i o n v a l v e i n t o a m i x i n g chamber, and t h e a n a l y t e c o n c e n t r a t i o n i n t h e e f f l u e n t v a r i e d e x p o n e n t i a l l y as a f u n c t i o n o f t h e t i m e elapsed a f t e r t h e i n j e c t i o n .A s i m i l a r o n - l i n e procedure was used t o d i l u t e serum samples i n t h e d e t e r m i n a t i o n o f Ca and Mg by FAAS (1051). The method was l a t e r m o d i f i e d (C2445) t o achieve c o n t r o l l e d d i s p e r s i o n o f c l i n i c a l samples i n a c a r r i e r stream w i t h o u t t h e use o f a r o t a r y i n j e c t i o n v a l v e .A p r e c i s e sample volume ( 1 - 150 111) was drawn i n t o a probe tube by a p e r i s t a l t i c pump d r i v e n by a computer-controlled s t e p p i n g motor. The probe was t h e n t r a n s f e r r e d t o a r e s e r v o i r c o n t a i n i n g t h e c a r r i e r s o l u t i o n , t h e pump r e - s t a r t e d , and t h e sample p r o p e l l e d through t h e d i s p e r s i o n t u b e where i t was d i l u t e d .A new I C P m i c r o c o n c e n t r i c n e b u l i z e r was developed (564) f o r d i r e c t i n t r o d u c t i o n o f l i q u i d sample f l o w s from F I o r HPLC equipment, The d e v i c e was i n s e r t e d i n t o t h e t i p of t h e c o n v e n t i o n a l sample i n t r o d u c t i o n t u b e o f an I C P t o r c h , and s t a b l e plasma c o n d i t i o n s were maintained a t sample f l o w r a t e s o f 100 - 200 p1 min-’ f o r b o t h aqueous and o r g a h i c s o l v e n t s (see a l s o S e c t i o n 1.2.1.5).S t u d i e s on t h e i n t e r f a c i n g o f HPLC and F I systems t o an I C P v i a a pneumatic n e b u l i z e r were r e p o r t e d (C1217).An air-segmented sample i n t r o d u c t i o n procedure (1826) was d e v i s e d f o r o p e r a t i o n w i t h an I C P d i r e c t r e a d i n g spectrometer. The auto-sampler d e l i v e r e d 100 p1 s o l u t i o n volumes i n t h e sequence, air/sample/air/rinse/air/sample, etc.D e t e c t i o n l i m i t s were 1.5 - 10 t i m e s p o o r e r t h a n f o r continuous n e b u l i z a t i o n . E l e c t r o t h e r m a l a t o m i z a t i o n sample i n t r o d u c t i o n procedures f o r ICP-OES were developed based on e i t h e r a e r o s o l d e p o s i t i o n o f 25 - 500 ~1 volumes o n t o a g r a p h i t e b o a t o r probe (C1296), o r d i r e c t e v a p o r a t i o n o f 5 L I ~ samples from a Ta f i l a m e n t (1760). A Re f i l a m e n t atomizer was used f o r t h e i n t r o d u c t i o n o f micro-sample volumes i n ICP-MS (C1223).An automatic g r a p h i t e r o d sample i n s e r t i o n d e v i c e f o r ICP-OES (C1490) has been a p p l i e d i n t h e a n a l y s i s o f soils,62 semiconductor m a t e r i a The i n f l u e n c e o f t h e was a l s o i n v e s t i g a t e d F u r t h e r i n f o r m a Arzalytical Atomic Spectroscopy s, and b i o l o g i c a l samples (see ARAAS, 1983, 13, Ref. 833). sample-cup d e s i g n on a n a l y t e v a p o r i z a t i o n w i t h t h i s system (711; see a l s o S e c t i o n 1.2.1.2). i o n was p r o v i d e d (531, 769, C1190, C2437) on t h e development and a p p l i c a t i o n o f automatic g r a p h i t e probe sample i n t r o d u c t i o n d e v i c e s f o r ETA-AAS (see ARAAS, 1983, 13, 54 and a l s o S e c t i o n 1.4.3).F a c t o r s considered when assessing t h e optimum c o n f i g u r a t i o n f o r probe a t o m i z a t i o n i n c l u d e t h e d i r e c t i o n o f e n t r y o f t h e probe i n t o t h e atomizer tube, t h e mechanisms f o r moving t h e probe, t h e shape and m a t e r i a l o f t h e probe, and t h e i n f l u e n c e o f t h e t u b e m a t e r i a l and a t o m i z a t i o n temperature on t h e magnitude o f probe AA s i g n a l s .Other r e f e r e n c e s o f i n t e r e s t - Device f o r e l e c t r o l y t i c s e p a r a t i o n o f Hg p r i o r t o d e t e r m i n a t i o n by cold-vapour AAS: 207.FI-AFS d e t e r m i n a t i o n o f Hg: 452. Laser v a p o r i z a t i o n o f s o l i d samples i n OES and ETA-AAS: 714. Pneumatic mechanism f o r p o s i t i o n i n g o f a sample c a r r i e r i n s i d e a g r a p h i t e t u b e atomizer: 258. S e n s i t i v i t y enhancement i n FI-FAAS by use o f o r g a n i c s o l v e n t s : 686.Spark v a p o r i z a t i o n o f s o l i d s i n t o an I C P : C1115, C1584. Standard a d d i t i o n F I method f o r d e t e r m i n a t i o n o f C r i n s t e e l s by FAAS: 1254. Use o f F I t o p r e v e n t n e b u l i z e r blockage i n t h e DCP-OES a n a l y s i s of b i 01 o g i c a l samp 1 es: C1295. W-wire probe f o r sample i n t r o d u c t i o n i n ETA-AAS: 1758. 2.5 INSTRUMENT CONTROL AND DATA PROCESSING 2.5.1 Emission A n a l y t e wavelength s e l e c t i o n procedures were t h e s u b j e c t o f f u r t h e r i n v e s t i g a t i o n i n ICP-OES. Slew-scanning programmable monochronators must be a b l e t o i d e n t i f y a c c u r a t e l y t h e a n a l y t e emission peak l o c a t i o n , o f t e n a t c o n c e n t r a t i o n s c l o s e t o t h e d e t e c t i o n l i m i t o r i n t h e presence o f h i g h l y s t u c t u r e d s p e c t r a l background.A s i d e - l i n e i n d e x i n g procedure f o r peak searching i n ICP-OES was described, i n which a nearby l i n e , e i t h e r n a t u r a l l y p r e s e n t i n t h e sample o r added as a " s p i k e " p r i o r t o t h e a n a l y s i s , was used as a r e f e r e n c e p o s i t i o n f o r peak i d e n t i f i c a t i o n (C45, 711, C1334, C1507).The method was claimed t o reduce t h e e f f e c t o f s p e c t r a l i n t e r f e r e n c e s i n complex m a t r i c e s and improve d e t e r m i n a t i o n s near t h e d e t e c t i o n l i m i t . Automation o f a n a l y t e and background wavelength s e l e c t i o n was achieved i n another s t u d y byInstrumen fa tion 63 u s i n g s o f t w a r e a l g o r i t h m s which attempted t o o p t i m i z e i n s t r u m e n t a l parameters f o r i n d i v i d u a l samples (C1332, C1508).A s e t o f samples r e p r e s e n t a t i v e o f t h e sample t y p e t o be analysed was examined, and t h e s o f t w a r e generated s p e c t r a l p r o f i l e s s u r r o u n d i n g p o t e n t i a l a n a l y t e wavelengths f o r each s p e c i f i e d element.Using operator-weighted c h a r a c t e r i s t i c s such as t h e SBR, and t h e degree o f s p e c t r a l i n t e r f e r e n c e , t h e s o f t w a r e s e l e c t e d t h e most a p p r o p r i a t e wavelength f o r each element.Background c o r r e c t i o n p o s i t i o n s were placed i n s p e c t r a l r e g i o n s which determined t o be f r e e from peak-shaped f e a t u r e s by means o f p a t t e r n r e c o g n i t i o n r o u t i n e s . were Software has been developed f o r use w i t h a computer-controlled monochromator f o r q u a l i t a t i v e a n a l y s i s by ICP-OES (C1333).S p e c t r a l i n t e r f e r e n c e s were p r e d i c t e d u s i n g a l i b r a r y o f e x p e r i m e n t a l l y d e r i v e d l i n e s based on t h e most s e n s i t i v e wavelengths o f 50 elements. Wavelength r e g i o n s were measured u s i n g a c o n v o l u t i o n r o u t i n e f o r peak searching. Only peaks w i t h i n a predetermined i n t e r v a l around t h e i n s t r u m e n t a l wavelength were i n t e r p r e t e d as p o t e n t i a l a n a l y t e peaks.The simultaneous occurrence o f s e v e r a l o f t h e most s e n s i t i v e l i n e s was used t o c o n f i r m t h e presence o f a n a l y t e . The s o f t w a r e a l s o f e a t u r e d a r o u t i n e a l l o w i n g t h e r a p i d i n d i v i d u a l o p t i m i z a t i o n o f plasma parameters i n o r d e r t o e s t a b l i s h compromise multi-element c o n d i t i o n s f o r q u a l i t a t i v e a n a l y s i s .A s i n g l e s o f t w a r e package, w r i t t e n i n PASCAL, was d e s c r i b e d f o r t h e c o n t r o l o f a h i g h r e s o l u t i o n scanning monochromator and a polychromator s h a r i n g a common I C P source (C1336).D e t e c t i o n l i m i t s o b t a i n e d u s i n g t h e polychromator were r e p o r t e d t o be comparable t o t h o s e found u s i n g t h e t r a c e a n a l y s i s mode o f t h e s e q u e n t i a l instrument. The f e a t u r e s o f a computer-controlled slew-scanning e c h e l l e monochromator f o r DCP-OES were d e s c r i b e d (C35, C124, C1342).The development o f a s o f t w a r e package which allowed s i n g l e o r m u l t i p l e wavelength o p e r a t i o n o f t h e system i n e i t h e r o p e r a t o r i n t e r a c t i v e o r t o t a l l y automatic modes was discussed. The a p p l i c a t i o n o f computers i n t h e l a b o r a t o r y was t h e s u b j e c t of much discussion, and a t t e m p t s were made t o e s t a b l i s h general p r i n c i p l e s r e g a r d i n g t h e development o f hardware and s o f t w a r e i n t h i s f i e l d (C51, C52, C53, C1178, C1180, (2418).Computer-aided method development techniques were a p p l i e d i n t h e area o f s p e c t r a l d a t a m a n i p u l a t i o n , comparison, and i n t e r p r e t a t i o n (C40, C1507, C1199).The use o f l i b r a r y spectra, s p e c t r a l c o n v o l u t i o n and s u b t r a c t i o n techniques, and t h e g e n e r a t i o n o f composite s p e c t r a i n ICP-OES were evaluated. Methods f o r t h e complete automation o f source and o p t i c a l parameter s e l e c t i o n and data p r o c e s s i n g f u n c t i o n s were d e s c r i b e d (C1198, C1343).and t h e a b i l i t y o f t h e I C P t o meet t h e requirements o f o n - l i n e process c o n t r o l was assessed (C1345). The a p p l i c a t i o n o f computers i n l a b o r a t o r y management and i n remote d i a g n o s t i c s f o r s o f t w a r e updates and system maintenance i n ICP-OES (C56, C1548) a l s o i n d i c a t e d t h e development of automatic systems on a l a r g e r scale.64 Analytical A tomic Spectroscopy Other r e f e r e n c e s o f i n t e r e s t - A d a p t i v e smoothing o f s p e c t r o s c o p i c d a t a : 1061.Data p r o c e s s i n g f o r a Paschen-Runge spectrometer: C280. Development o f a computer-controlled programmable monochromator system f o r ICP-OES: 466. O p t i m i z a t i o n and s t a b i l i t y i n DCP-OES and ICP-OES: C54, C57, C1179, C1379, C1381.Software-based q u a l i t y c o n t r o l i n I C P a n a l y s i s : C1310. Software f o r ICP-MS: C1338, C1396. 2.5.2 A b s o r p t i o n The a p p l i c a t i o n o f l a b o r a t o r y microcomputers i n t h e c o n t r o l o f ETA-AAS i n s t r u m e n t a t i o n has been a p a r t i c u l a r l y prominent area o f i n v e s t i g a t i o n .Holcombe (C1178) discussed i n t e r f a c i n g techniques and approaches t o s o f t w a r e development f o r microcomputer-controlled i n s t r u m e n t a t i o n . The use o f machine language sub-routines f o r r a p i d d a t a a c q u i s i t i o n purposes was assessed, and examples o f t h e a p p l i c a t i o n o f BASIC and FORTRAN programs f o r d a t a c o l l e c t i o n and m a n i p u l a t i o n s were given.The use o f an Apple I1 microcomputer i n t h e development o f a h e a t i n g c o n t r o l program f o r a g r a p h i t e f u r n a c e atomizer placed w i t h i n t h e vacuum system o f a MS was described. Several o t h e r systems were r e p o r t e d which used microcomputers t o p r o v i d e r a p i d d a t a a c q u i s i t i o n f a c i l i t i e s f o r ETA-AAS (C410, 1067, C1212, C1560).An automated data a c q u i s i t i o n system was d e s c r i b e d which enhanced t h e performance o f a Perkin-Elmer 380 spectrometer (C1544). An Apple microcomputer and an ISAAC 91A system were employed t o p r o v i d e simultaneous peak h e i g h t and area measurement, b a s e l i n e s u b t r a c t i o n , d i g i t a l smoothing, c a l i b r a t i o n , d a t a m a n i p u l a t i o n and s t o r a g e f a c i l i t i e s .Data m a n i p u l a t i o n programs were w r i t t e n i n extended BASIC (LABSOFT) which executed machine language sub-routines t o achieve a h i g h e r speed o f d a t a a c q u i s i t i o n .A microcomputer-control l e d AA/AE spectrometer system was d e s c r i b e d which employed wavelength m o d u l a t i o n f o r background c o r r e c t i o n i n b o t h measurement modes (C409, C1555, C2440, see a l s o S e c t i o n 2.3). The system, programmed i n BASIC, i n c o r p o r a t e d a machine language sub-routine f o r d a t a a c q u i s i t i o n , and c o u l d be used w i t h e i t h e r ETA o r flame atomizers.The r a p i d a c q u i s i t i o n o f d a t a and t h e f l e x i b i l i t y o f measurement o f f e r e d by c o m p u t e r - c o n t r o l l e d i n s t r u m e n t a t i o n has allowed t h e s t u d y o f a n a l y t e peak shapes i n ETA-AAS. H a r n l y (C1213, C1558) used a minicomputer t o make measurements o f t h e h e i g h t , area, and temporal c h a r a c t e r i s t i c s o f ETA-AAS s i g n a l s .The accuracy and p r e c i s i o n o f t h e measurements were examined as a f u n c t i o n o f s o f t w a r e f i l t e r i n g o v e r t h e course o f t h e atomizer l i f e t i m e . Peak c h a r a c t e r i s t i c s were a l s o i n v e s t i g a t e d u s i n g a 1 6 - b i t microcomputer-controlled d a t a a c q u i s i t i o n system (C410).Software was developed and t e s t e d t o f i tInstrumentation 65 a n a l y t i c a l requirements i n terms o f s e n s i t i v i t y , d e t e c t i o n l i m i t , and p r e c i s i o n . An improved method o f s e p a r a t i n g s p e c i f i c and n o n - s p e c i f i c a b s o r p t i o n peaks i n ETA-AAS u s i n g a d i g i t a l c a p t u r e technique was o u t l i n e d (C1560).The s i g n a l c o u l d be d i s p l a y e d a f t e r measurement, a t reduced speed on a c h a r t recorder. It was shown t h a t i t was p o s s i b l e t o determine Pb i n 1% m / V sodium c h l o r i d e s o l u t i o n s w i t h o u t background c o r r e c t i o n by temporal r e s o l u t i o n o f t h e a n a l y t e and n o n - s p e c i f i c a b s o r p t i o n s i g n a l s .S a l i t and Parsons (C1215) discussed t h e t o p i c o f s o f t w a r e d r i v e n i n s t r u m e n t a t i o n , and r e f e r r e d t o t h e development o f a multi-element ETA-AAS system as an i l l u s t r a t i v e example. Software improvements have been r e p o r t e d f o r Perkin-Elmer AA instruments.These i n c l u d e d a c a l i b r a t i o n a l g o r i t h m f o r FAAS (1820), a g r a p h i c s s o f t w a r e package f o r Zeeman-effect ETA-AAS (C1543, 1885), and a m o d i f i c a t i o n t o HGA g r a p h i c s s o f t w a r e t o generate data d i r e c t l y i n terms o f c o n c e n t r a t i o n (1882). Other r e f e r e n c e s o f i n t e r e s t - A p p l i c a t i o n of automation and c o m p u t e r i z a t i o n t o a s o i l t e s t i n g l a b o r a t o r y : 1466.Automated AAS i n s t r u m e n t s : C1337, C1748. H i g h speed ADC f o r ETA-AAS: 199. M o t o r o l a micromodules as an i n t e r f a c e f o r a flame photometer: 463. S i g n a l i n t e g r a t i o n i n ETA-AAS: 237, 238. 2.6 COI'JIPLETE INSTRUPIENTS 2.6.1 Emission There i s undoubtedly growing i n t e r e s t i n t h e use o f h i g h r e s o l u t i o n spectrometer systems f o r ICP-OES (see a l s o S e c t i o n 2.2.1).Boumans and Vrakking (2257, 2258, 2259) have o u t l i n e d t h e c h a r a c t e r i s t i c s and performance o f a novel t y p e o f e c h e l l e monochromator w i t h p r e d i s p e r s e r i n a p a r a l l e l s l i t arrangement f o r h i g h r e s o l u t i o n AES.The c h a r a c t e r i s t i c s o f t h e J o b i n Yvon JY38 VHR h i g h r e s o l u t i o n spectrometer were d e s c r i b e d (C1747). T h i s 1 m monochromator was equipped w i t h a 3600 l i n e mm-l h o l o g r a p h i c g r a t i n g w i t h a r e c i p r o c a l l i n e a r d i s p e r s i o n o f 2.66 8 mm-' and a wavelength range o f 1700 - 5000 1 i n t h e f i r s t o r d e r .The JY38 VHR has a l s o been combined w i t h a JY32 Paschen-Runge polychromator, and t h e c o n t r o l s o f t w a r e f o r t h i s system d e s c r i b e d (C1336, see S e c t i o n 2.5.1). McLaren and Mermet (2260) used t h e JY38 VHR spectrometer t o i n v e s t i g a t e t h e i n f l u e n c e o f t h e d i s p e r s i v e system on a n a l y t i c a l performance i n ICP-OES (see S e c t i o n 2.2.1).A r a p i d scanning programmable vacuum monochromator has been d e s c r i b e d f o r ICP-OES i n t h e low U.V. r e g i o n (C39, C55, C115, C339, C2457). The e n t i r e o p t i c a l p a t h o f t h e i n s t r u m e n t was evacuated, w i t h t h e e x c e p t i o n o f t h e p a t h66 Analytical Atomic Spectroscopy between the plasma source and a CaF2 lens.This dual channel air and vacuum instrument was claimed to offer improved stability in comparison to a purged system, and a RSD of 0.5% was reported for the determination of S at 166.67 nm, over a one hour period. An arc/spark source echelle spectrometer systein has been constructed (C1202, C1575, C1908, C1923).The combination was intended as an alternative to plasma AE techniques where solid samples have to be analysed. The application of plasma instrumentation in chromatographic detection continues to increase. Instrument systems were described for GC-MIP (261, 609). HPLC-DCP (1397)' and HPLC-ICP (821). A microwave-induced plasma emission instrument was described which was used in the determination of halogens in the stratosphere (108).A TMOIO cavity was used to couple power to a He plasma operated at 0.1 - 260 Torr. Two new types of Ar MIP, a stable 3-filament and a toroidal plasma, were described which could be generated using a modified TMOIO cavity (301). Detection limits obtained using these systems were found to be in the range 1 - 50 ng ml-'.The development of low-power, low-flow instrumentation for ICP-OES has continued in the last year (see ARAAS, 1983, 13, 59). Van der Plaas and de Galan (Cl080, 2251) described a radiatively cooled segmented torch with a central part made of boron nitride. The plasma could be operated at 600 W and 1 1 mi"-' Ar, and exhibited analytical characteristics comparable to those of a conventional ICP (see Section 1.2.1.5).Other references of interest - Application of a low-power r.f. generator in ICP-OES: C1588. Electrothermal atomizers as sources for AES: 831, 1142, C1443, C1555, C1623. Emission spectrometric determination of Mg in steel using pulse distribution analysis: 212. Instrument columns in Spectrochimica A c t a : 1475, 1805, 2205, 2320.Modification of a Plasmatherm ICP to enable r.f. power modulation: 553, 1273. Patent for a DCP burner: 257. Plasmon spectroscopy for identification of inorganic solids: 715. Spectrochemical LIDAR for elemental analysis of atmospheric aerosols: 448. Two jet plasmatron for spectrochemical analysis: 1283, 1815. 2.6.2 Absorption The first report of the Instrumental Criteria Sub-Committee of the Analytical Methods Committee (767), which tabulated features o f FAA spectrometers to be considered by potential purchasers when making comparisons, was reported in full last year ( A R A A S , 1983, 3, 61).The second report which deals with AAInstrumen tation 67 spectrometers p r i m a r i l y designed f o r use w i t h ETA has now been p u b l i s h e d (Anal.Proc., 1985, 2, 128). The notes on t h e s c o r i n g t o f a c i l i t a t e comparison and t h e i n t r o d u c t i o n a r e i d e n t i c a l t o those o f t h e f i r s t r e p o r t and t h e new g u i d e i s reproduced as Table 2.6 (see page 68). The p o s s i b i l i t y o f u s i n g a Zeeman-effect ETA-AAS i n s t r u m e n t f o r coherent f o r w a r d s c a t t e r i n g (CFS) spectroscopy was discussed (C1493).The i n s t r u m e n t s i g n a l p r o c e s s i n g e l e c t r o n i c s were m o d i f i e d and a p o l a r i z e r was i n s t a l l e d on e i t h e r s i d e o f t h e a t o m i z e r t o a l l o w measurement o f t h e CFS s i g n a l . Commercial HCL o r EDL l i g h t sources were employed. D e t e c t i o n l i m i t s o b t a i n e d u s i n g t h e system were e q u i v a l e n t t o o r up t o 10 t i m e s b e t t e r t h a n those achieved by ETA-AAS, depending on t h e element and t h e b r i g h t n e s s o f t h e l i g h t source. The c o n s t r u c t i o n and behaviour o f a non-dispersive multi-element a n a l y s i s system based on t h e V o i g t e f f e c t was o u t l i n e d (C1156).R a d i a t i o n from 6 a l t e r n a t e l y pulsed HCLs was passed through a flame atomizer, b r i d g e d by 2 p o l a r i z e r s , i n a magnetic f i e l d . S i g n a l s r e s u l t e d from t h e magneto-optic i n t e r a c t i o n o f resonance r a d i a t i o n w i t h corresponding elements i n t h e flame and were maximized by v a r y i n g t h e o f f s e t angle between t h e p o l a r i z e r s .D e t e c t i o n l i m i t s o b t a i n e d u s i n g t h e i n s t r u m e n t were r e p o r t e d t o be s i m i l a r t o those achieved u s i n g c o n v e n t i o n a l FAAS. A segmented-rod a t o m i z e r was d e s c r i b e d which allowed samples t o be atomized d i r e c t l y w i t h o u t p r i o r d r y i n g o r p y r o l y s i s , thus r e d u c i n g t h e t i m e i n t e r v a l between sample i n j e c t i o n s t o 30 s ((2467; see a l s o ARAAS, 1983, 13, 39).The a t o m i z e r was operated i n c o n j u n c t i o n w i t h a Zeeman-effect background c o r r e c t i o n system i n which t h e magnetic f i e l d , modulated a t 50 Hz, had a l o n g i t u d i n a l o r i e n t a t i o n .The e f f e c t s o f HCL c u r r e n t , magnetic f i e l d s t r e n g t h and a t o m i z e r d e s i g n on AAS s e n s i t i v i t y were discussed. The c h a r a c t e r i s t i c s o f a Zeeman-modulated AAS i n s t r u m e n t equipped w i t h a W-strip atomizer were d e s c r i b e d (C1540, 2044). D e t e c t i o n l i m i t s o b t a i n e d w i t h t h e i n s t r u m e n t were i n general comparable t o ETA-AAS values.Peak t a i l i n g i n t h e d e t e r m i n a t i o n o f r e f r a c t o r y m e t a l s was r e p o r t e d t o be decreased by r e d u c i n g t h e atomizer c r o s s - s e c t i o n above t h e sample area, t h u s a t t a i n i n g h i g h e r temperatures. E l e c t r o t h e r m a l a t o m i z e r s were used i n a v a r i e t y o f novel i n s t r u m e n t c o n f i g u r a t i o n s b o t h f o r a n a l y t i c a l and d i a g n o s t i c purposes (see S e c t i o n 1.4).These i n c l u d e d FT-i.r. spectrometry (1836), PIS (C1209, C1210, C1422), and m u l t i p l e wavelength spectrometry (C1158, C1214). A new, s i n g l e channel continuum source atomic a b s o r p t i o n / a t o m i c emission spectrometer has been c o n s t r u c t e d (C409, C1555, C2400; see a l s o S e c t i o n s 2.3 and 2.5.2).The i n s t r u m e n t employed an Apple I I e microcomputer f o r d a t a a c q u i s i t i o n and s i g n a l processing, and p r o v i d e d automatic background c o r r e c t i o n by a wavelength m o d u l a t i o n procedure. Software has been developed t o a l l o w e i t h e r flame o r f u r n a c e measurements.68 Analytical Atomic Spectroscopy TABLE 2.6 INSTRUMENTAL CRITERIA SUB-COMMITTEE INSTRUMENT EVALUATION FORM Type of Instrument: Atomic-absorption Spectrophotometers for Electrothermal Atomisation Manufacturer: Model No: Feature 1.Hollow-cathode lamp supply ( a ) Methodof lamp alignment (b) Modulation 2.Atomiser ((I) Alignment (b) Electrical contact (c) Tube dimen- sions ( d ) Accessibility for sample intro- duction (e) Purge gasentry v) Ease of rever- sion to flame operation (g) Cooling system ( h ) Tube compo- sition and coatings (i)Tube replace- ment and ease of cleaning Definition and/or test procedures and guidance for assessment Two axis adjustment by accessible controls preferred.Type and frequency-score high for electronic modul- ation. non-multiples of mains frequency and also for highest frequency Maximum score for stable. lateral. rotational and vertical adjustment with good accessibility. Score maximum for greatest area of contact compatible with robustness andsimple replacement of tube. Score highest for smallest tube with a sample capacity of 25 pI and with the ability to hold a platform of at least IOflsample capacity. Score highest for furnace with ready access.Score maximum for gas entry at end of tube with exit in middle. Maximum score for simplicity of change-over. Score highest for most rapid cooling. with reasonable economy of gas or water. Score maximum for the widest range of materials and coatings available.Score highest for simple dismantling of tube and work- head. mportanc VI VI v1 VI VI I I I I Reason Alignment of source on optical axis. particularly important for ETA because of the need to match exactly the beam from the line source and the continuum source if used for background correction. Suppression of mains noise and unwanted d.c. signals, in particular emission from the furnace walls. Signal rise time is very short.therefore signal distortion may he considerable if modulation frequency is low. Alignment of furnaces critically affects reproducibility and sensitivity. Consistent low contact resistance ensures reproducible heating cycles and increases livesof tube and furnace. Small tubes heat up rapidly. whereas large tubes simplify sample handling and give longer residence time.This recom- mendation is thought to be a reasonable compromise between conflicting requirements. Facilitates manual sample introduction and may allow use of slurries and solid samples. Reduces non-specific absorption and fogging of windows if fitted. Self-explanatory. Increases speed of analysis and improves reproducibility of operating conditions and analytical results.Some coatings, e.g.. pyrolytic, increase sensitivity for some elements and reduces certain interferences. Regular cleaning is required to prevent contamination of tubes and furnace structure. Score PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF STInstrumen tation Feature 2A. Aromiserpower ( a ) Maximum temperature ( b ) Maximum heating rates SUPPIY ( c ) Stabilisation (d) Capacity 3.Monochromator ~ optics ( 0 ) Temperature stability ( b ) Background correction. (See NOTE II (c) Focal length and f number (d) Slits (4) Grating Wavelength ( i ) Readout precision Definition and/or test procedures and guidance for assessment Score maximum for highest temperature attainable.Score maximum for fastest temperature rise time attainable. Score maximum for temperature feed-back system which operates over widest range of temperatures. Optical sensors are rapid and reliable at higher temper- atures. Thermocouple and resistance thermometer based systems are useful when close temperature control is important at lower temper- atures. However, these devices suffer from problems of fragility and contact reproducibility. Voltage feed-back control is less effective than the above systems.Score maximum for highest power rating compatible with acceptable size and ability to operate from available power supply. AWC change in wavelength per degree. The smaller this value the better is the stability. Score maximum for efficient simultaneous background correction for the maximum number of elements.Additional score for ease of replacement of source if used. Score maximum for long focal length and highfnumber. Score maximum for contin- uously variable slits, intermediate for stepwise adjustment. minimum for fixed slits. Additional score for height adjustment facility. Modified Czerny - Turner mount generally preferred to Ebertor Littrow asstray light characteristics are better.Maximum score for blaze angle nearest wave- lengths of maximum interest. Four-figure digital readout preferred. mportanci VI VI VI I Reason Higher temperature facilitates the determination of refractory elements. Higher temperature rise rate$ increase sensitivity for some elements andminimise matrix interference. Reproducible temperatures are essential for accurate and reproducible results.Convenience and ability to heat furnace to the maximum temperature rapidly and reproducibly. Elimination of instrumental drift. oarticularly important with long iample runs using an autosampler. 3bligatory for ETA due to high ion-atomic absorption. zompatibility of optical beam and 'urnace tube dimensions. so as to avoid excessive loss of source .adiation and prevention of 'urnace wall emission from raching the detector.Full control of slit adjustment ~llowspectral discrimination and control of luminous flux. iuitable blaze angle required to :mure adequate source radiation hroughout range of interest. The iseful working range is approx- mately from 213 to 3 times the )laze wavelength.the fall in :fficiency being particularly ,harpat short wavelengths. Sase of re-setting instrument. icorc - PS WF ST PS WF ST Ps WF ST PS WF sl - PS WF ST PS WF ST PS WF ST PS WF ST Ps WF ST PS rKF sy 6970 A nuly tical A tomic Spectroscopy Feature (ii) Repeatabilit) (g) Number of optical elements (h) Dispersion resolution and resolving power ( i ) Single or double beam 4.Gas control system (u) Gas stop mode (b) Number of gas inlets (c) Flow-rate indicators 5. Detectors 6. EHTsupply (a) Voltage range (b) Means of adjustment 7 . Amplifier (4 TYF ( b ) Integration and peak retrieval facilities (c)Time constants Definition and/or test procedures and guidance for assessment Maximum score for smallest range of transmission values following re-setting to a previously located line.Score maximum for minimum number of optical elements. Score extra for coated optics. Score maximum for: small angular deviation; high angular dispersion; small reciprocal linear dispersion; small resolution; high resolvingpower. Double beam preferred. Score for availability. Score maximum for maximum number. Score maximum for digital indication. Score maximum for the availability of a photo- multiplier tube which meets most requirements, and score additionally for ease of interchange with alternative photomultipliers.Score maximum for widest range and digital readout of applied voltage. Adjustment by calibrated control preferred. Automatic continuous adjustment of EHT is not desirable. Synchronously demodulated “lock-in” i s normal: score maximum for this type with largest number of ranges.Score maximum for avail- ability of both peak height and area modes. Score maximum for fastest response. mportanct I I NVI NVI I Reason Ability to locate consistently the analytical wavelength. Maximum energy throughput with minimum scatter. Coated optics will increase the useful life of the instrument. Normally adequate for AAS by ETA.Double beam eliminates long term drift, which is advantageous for long sample runs. “Gas Stop” improves sensitivity for many elements due tolonger residence time of atoms. Additional gas inlets are required to handle inert gas(es) and hydrogen (to improve sensitivity for some elements). and possibly oxygen tospeed ashing. Ease of reproducing conditions. A suitable photomultiplier is required to cover the wavelength range of the elementsof interest.Where one photomultiplier cannot give sufficient spectral range ease of interchange is important. The abilityof the replacement to attain working stability rapidly i s also important. A wide range of applied EHT allows for flexibility of adjustment of other instrument parameters. while digital readout aids reproducible instrument operation.A consistent signal to noise ratio can only be achieved by operation at constant EHT. Provides removal of unwanted d.c. signalsand operational versatility. Area measurements may reduce effects of variable matrices and improve accuracy. Providing amplifier has sufficiently fast response, peak height retrieval often gives best precision. Signal rise times and atom residence times are short when using ETA. Ability to measure rapidly changing signals is, therefore, essential.kart PS WF ST PS WF ST PS WF ST - PS WF ST - PS WF ST PS WF ST PS WF ST PS WF ST - - PS WF ST PS WF ST - PS WF ST PS WF ST PS WF STInstrumen tation 71 Feature 8. Outpur ( a ) Readout type: (6) Interface (c) Curve fitting software 9.Programming of operational parameters (a) Stages in operational cycle (6) Ramplstep (c) Sequence control (d) Fail safelnianu; override provision (e) Programme sequence storage Operational 10. Sample handling system (a) Sample intro- duction (6) Number of samples and standards (c) Facilities for sample and standard manipu- lation and treat- ment Definition andlor test procedures and guidance for assessment Score maximum for avail- ability of analogue, digital, printer and graphic outputs.Score maximum for suitable standard interface. e.g., RS232, IEEE, BCDor ASCII. Score maximum for avail- ability of statistically valid procedures. Number of independently programmable heating cycles- minimum requirement -dry." "ash," "atomise" and "clean." Score extra for additional division of "ash" and "dry" stages.Number and range of heating rates available for each stage of operational cycle. Score maximum for greatest versatility. Can be microprocessor or electromechanical. The former. although more expensive. is to be preferred. Score accordingly. Score maximum for sensors to detect failure of cooling water. furnace temperature overrun and inert gas flow.together with provision for manual override of any operation. Score maximum for maxiinum number of programmes that can be automatically retrieved. Score maximum for full read- out of temperature - time sequence. Score maximum for fully automated sample handling system. Score maximum for sample turntable that allows maximum number of samples to be run with unattended operation.without degradation of calibration functions. Score maximum for most versatile programme(s) for standard dilutionladditions. matrix modification. replica- tion and rinsing. [mportancc VI I VI VI I VI Reason Digital readout and printer are particularlysuitable for quality control applications and measurement of small signals. Analogue and graphic outputs are beneficial for measuring transient peaks and developing methodsand procedures.To maximise compatibility with available printers or computers. "Least Squares" hyperbolic or polynomial fitting enables the use of moderately curved calibration functions without significant lossof precision. The four basic stages are essential: for more complex matrices. ability to vary drying and ashing stages in steps may greatly reduce matrix effects. Ability to vary heating rate within each stage may enable an interfering matrix to be removed without Imsofanalyte.Reproducible control of Jperating sequence. after setting up. is essential. Microprocessor :ontrolled instruments may not require "ramp" facilities. aseach itep can be sub-divided according to the user's needs. Instrument protection.Convenience of operation Essential to check operational Jarameters and for development )f analytical procedures. Automatic sample introduction improves precision and speed and may reduce interferences and improve accuracy. Speed. convenience and accuracy. Allows more flexible automation 3nd more efficient operation. kon PS WF ST - PS WF ST PS WF ST - PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST PS WF ST - PS WF ST PS WF ST PS WF ST72 Analytical Atomic Spectroscopy Feature (d) Range of sample sizes (e) Control system I I .Over-all performance (a) Base line stability (see NOTE II.111 and IV) (b) Tube life (c) Figures of merit (i) Precision (ii) Sensitivity (slope of calibration curve) Definition andlor test procedures and guidance for assessment Score maximum forwidest range of sample size without undue loss of precision.bearing in mind furnace capacity. Score maximum if linked to microcomputer that controls furnace operation. With the furnace in position allow 30 min for spectrometer to warm up then take readings at 2-min intervals for 1 h. Take a further 30 readings at 2-min intervals. each after injecting I 0 pi of 1% sodium chloride solution using the following pro- gramme: 10sdryat I(WJ°C. 30s ash at 80U"Cand 2 s atomise at MXI "C, foliowed with 4-s clean at maximum temperature and7Os for cooling. Calculate standard deviations. check for drift and score accordingly. Set up the instrument according to the manufact- urer's recommendations for the analysisof lead. Use 1%" sodium chloride as the matrix and include a 4 s clean at maximum temperature.Repeat this analysisuntil either the signal undergoes a marked reduction. the precision degrades or the tube fails completely. Score maximum for the largest number of cycles before unacceptable degradation of precision, accuracy or tube Use a blank and concen- trations of test elements to give nonnnal absorbance of 0.0.005.0.01.0.02.0.05. U.1.0.2.0.5 and2.0 based on the manufacturer's sensitivity data.assuming thar a linear relationship exists. Measure eachsolution at least six times. using scale expansion for readings below 0.1. Solutions of 0.01 and0.2 should be measured at suitable intervals to obtain 30 replicates from which the precision data can be obtained. Calculate standard deviation and score maximum for lowest.Calculate slope of line and score maximum for highest occurs. slope. mport ancc NVI I Reason 'lexibility and convenience 'mproves degree of automation. Xeplication combined with online ,tatistics can ensure analysis s performed to presst confidence imits. 4ffects accuracy and precision. h i s is particularly important if inattended automatic operation s envisaged.The first series of neasurements evaluates electronic btahility while the suhsequent neasurements test the abilityof he furnace to clear a matrix uccessfully without "fogging" any Jptical surfaces. 4ffects ahilityof instrument to )e left for long periods of inattended operation. May lave mnsiderahle bearing on nstrument running costs. ielf explanatory. klf explanatory. - korc PS WF ST - PS WF ST - ps WF ST PS WF ST PS WF ST PS WF STInstrumentation 73 Feature (iii) Linear rang( (iv) Detection limit (v) Curve correction 12.Value formoney Points perf Definition andlor test procedures and guidance for assessment Calculate from calibration curve. Score highest for widest linear range. Calculate the concentration of solution that gives rise to a signal equal to twice the standard deviation of the reagent blank.measured at or near the limit of detection. Score maximum for lowest. Use the curve correction facility to linearise the calibration function and analyse a solution with a known concentration and a nominal absorbance of I .2-1.5. Score maximum for the most accurate result. Sum of previous sub-totals divided by the purchase price ofthe instrument.Subject to proportional scoring and weighting factor as for previous features. Include ST in grand total. mportann I NOTES [I] The efficiency of most background correction systems depends on the availability of equal time constants in both channels of the amplifier and the ability to match the source image in both size and intensity for both channels. Conventional background correction is effec- tive for most situations but is unable to deal with a structured background. Alternative systems, such as Zeeman or Smith - Hieftje, which have recently become available, are thought to be better in this respect and do not require a separate source.However, at the time of publication of this document. the sub-committee is not in a position to evaluate such systems fully.A test for the efficiency can be made by evaluating the effect of a 1000-fold excess concentration of aluminium (as the chloride) on the analysis of a suitable concentration of arsenic at 193.7 nm. This is most easily performed using a direct graphics output, but satisfactory evaluation can be made using a conventional output if the analysis is repeated in the absence and presence of aluminium.Measurements can be made using a high speed recorder, but should normally be obtained as a digital readout from the instrument and printer. In either instance the "peak retrieval" facility should be used and both peak height and peak areas should be recorded. [II] Reason Self explanatory. Self explanatory. Self explanatory Simple instruments are often good value for money.whereas those with many refinements are often costly. icore PS WF ST PS WF ST - PS WF ST - urn of otals PS WF ST sub- - irand total [HI] Choice of test matrix. The user can employ any matrix of interest; possibilities include seawater. urine, blood, aluminium chloride and plant material. However, the Sub-committee suggests that convenience may lead to the choice of something more generally available, such as 1-5% sodium chloride solution for most tests.:IV] Choice of test element. The user can employ any element(s) thought to be of importance. Some possibili- ties are: Arsenic at 193.7 nm-Evaluates performance at far ultraviolet end of instrument range. Makes considerable demands on background correction facilities if a matrix such as aluminium chloride is used.Lead at 21 7.0 or 283.3 nm-Commonly analysed ele- ment, which is relatively volatile and which may be incompletely resolved from an inorganic matrix. Cadmium ut 228.3 nm-The element can be deter- mined with high sensitivity but can be difficult to measure in the presence of even simple matrices such as sodium chloride. Chromium at 357.9 nm-Element with primary analy- tical line near end of the background correction range for deuterium arc lamp systems.74 Analytical Atomic Spectroscopy Other r e f e r e n c e s o f i n t e r e s t - AA u s i n g i n t r a c a v i t y l a s e r spectroscopy: 649.Hollow cathode as an a t o m i z e r i n AAS: 2040. Improving t h e performnce o f a CRA atomizer: 838. Simultaneous m u l t i - e l e m e n t AAS: 478, 774, 978. 2.6.3 F1 uorescence I n s t r u m e n t systems f o r AFS c o n t i n u e t o e x h i b i t a c o n s i d e r a b l e degree o f d i v e r s i t y i n t h e i r design. A computer-controlled multi-element AF system was discussed, i n which a 300 W Xe arc-lamp was employed as t h e e x c i t a t i o n source and an Ar-separated a i r / C H Fluorescence was d e t e c t e d u s i n g a photon counter i n t e r f a c e d t o an Apple I 1 microcomputer which a l s o c o n t r o l l e d a s t e p p i n g motor used t o slew-scan t h e monochromator t o t h e AF wavelength.The system was s e t up t o determine 20 elements i n a water m a t r i x . flame used as t h e atomizer (C1078). 2 2 Lasers c o n t i n u e t o be employed as e x c i t a t i o n sources i n AFS (see ARAAS 1983, 13, 70 and S e c t i o n 1.3.5.1). A pulsed demountable glow-discharge was used as an atom c e l l f o r l a s e r AFS.Lead atoms were s p u t t e r e d from t h e s u r f a c e o f copper and g r a p h i t e cathodes and were e x c i t e d by a p u l s e d frequency-doubled dye-laser a f t e r t h e d i s c h a r g e was switched o f f .The combination o f a “dark1’ atom c e l l w i t h non-resonance AFS gave r i s e t o v e r y low background s i g n a l s and a d e t e c t i o n l i m i t f o r Pb i n copper o f 0.1 ug g - l was reported. Laser-induced i n t e r m o d u l a t e d FAFS was suggested as an a l t e r n a t i v e method o f s c a t t e r c o r r e c t i o n i n AFS (1827).The l a s e r (bandwidth 0.05 nm) was s p l i t i n t o two beams which were modulated a t f r e q u e n c i e s fl and f2 and passed through t h e flame from o p p o s i t e d i r e c t i o n s . Lock-in a m p l i f i e r d e t e c t i o n a t a frequency fl + f2 was found e f f e c t i v e l y t o e l i m i n a t e t h e l i n e a r s c a t t e r i n g component o f t h e spectrum.Other r e f e r e n c e s o f i n t e r e s t - AFS w i t h a Grirnrn-type GDL: 2266. Laser-excited AF i n t h e DCP: C1076. M u l t i - e l e m e n t methods o f AFS: C1720. 2.7 CONMERCIAL INSTRUMENTS The accompanying t a b l e s p r o v i d e a l i s t o f c u r r e n t commercially a v a i l a b l e i n s t r u m e n t a t i o n a c c o r d i n g t o t h e most r e c e n t i n f o r m a t i o n s u p p l i e d by manufacturers o r t h e i r UK o r European agents.New i n s t r u m e n t s a r e l i s t e d s e p a r a t e l y a t t h e b e g i n n i n g o f each t a b l e and d e t a i l s a r e summarized below.tnstrumen tation 1 5 2.7.1 Emission P h i l i p s have introduced t h e PV 8050 series, a new range o f o p t i c a l emission spectrometers.The PV 8050 emission spectrometer has a Paschen-Runge c o n f i g u r a t i o n , covering a wavelength range o f 165 - 485 nm, and may be f i t t e d w i t h an o p t i o n a l programmable scanning channel. A r i g i d e x i t - s l i t p l a t e assembly i s used, a l l o w i n g customer s e l e c t i o n o f up t o 56 a n a l y t i c a l wavelengths. The PV 8050 spectrometer has a s i n g l e e x c i t a t i o n stand p o s i t i o n f o r 50 - 500 Hz monoalternance and i n t e r m i t t e n t d.c. arc sources.An o p t i o n a l Monk-Gillieson polychromator, f i t t e d w i t h i n t h e same temperature and pressure c o n t r o l l e d enclosure, i s a v a i l a b l e f o r l o n g wavelength l i n e s i n t h e 530 - 860 nm region. The PV 8055 has dual e x c i t a t i o n stand p o s i t i o n s w i t h i n d i v i d u a l source c o n t r o l c i r c u i t s and A r supply features t o a l l o w r a p i d changeover between sources.The PV 8060 i s a dedicated 50 MHz I C P system which incorporates an achromatic m i r r o r o p t i c a l c o l l e c t i o n system which gives a constant focus across t h e f u l l s p e c t r a l range.The PV 8065 o f f e r s a combination o f I C P and e l e c t r i c a l source u n i t s i n t h e same instrument. A l l systems are microprocessor c o n t r o l l e d , and data output i s handled by e i t h e r a Hewlett-Packard HP 9816 o r DEC m i c r o / l l computer. P h i l i p s a l s o continue t o o f f e r the PV 8020 s e r i e s o f emission spectrometers (see ARAAS 1983, 13, 89).As a r e s u l t o f a management buy-out agreement w i t h Bausch 3r Lomb, ARL i s now an independent company. The company has introduced t h e Model 3510 sequential I C P spectrometer system. The 1 m Czerny-Turner monochromator covers t h e wavelength range 165 - 800 nm and performs computer-controlled scans by means o f a stepper motor connected t o a worm-drive system.A new software package, SAS/ICP 35, has been created t o a1 low background c o r r e c t i o n , C a l i b r a t i o n and data storage and r e t r i e v a l functions. The Perkin-Elmer Plasma I 1 emission spectrometer i s a completely automated sequential I C P system which features s i n g l e o r dual 1 rn Ebert monochromators w i t h a choice o f holographic gratings. A separate 2-channel photometer on each monochromator performs simultaneous i n t e r n a l standardization.An o p t i o n a l vacuum system i s a v a i l a b l e f o r operation below 190 nm. The instrument i s c o n t r o l l e d by a PE Series 7000 1 6 - b i t computer. Background c o r r e c t i o n parameters may be selected by t h e user, o r a u t o m a t i c a l l y by t h e computer, using a software a l g o r i t h m t o survey t h e wavelength p r o f i l e (C40, C1332).A l i b r a r y o f over 50 000 a n a l y t i c a l wavelengths can be accessed from software t o f a c i l i t a t e l i n e s e l e c t i o n and i d e n t i f i c a t i o n . S e l e c t i o n and o p t i m i z a t i o n o f I C P source parameters a r e c o n t r o l l e d by t h e computer, i n c l u d i n g a f u l l y automatic i g n i t i o n procedure. A p r i n t e r w i t h graphics d i s p l a y f a c i l i t i e s , and an AS51 autosampler are a l s o available.Leeman Labs Inc. have introduced t h e i r Plasma-Spec I C P e c h e l l e g r a t i n g spectrometer i n Europe (C348). The system i s a v a i l a b l e as a r a p i d sequential76 Aizaly tical A tomic Spectroscopy Spectrometer i n which an aperture plate containing preset slits is mounted at the focal plane of the instrument and a moveable detector is directed by a computer to a pre-programmed co-ordinate for element selection.Horizontal and vertical wavelength scans are achieved by mechanical movement of the aperture plate rather than by grating translation.In the simultaneous mode, the sequential PMT is driven to a home position off the focal plane and a mask is lowered over the aperture plate to allow detection at up to 45 wavelengths. The instrument i s controlled by a 2-80 based microprocessor using menu driven software. A high resolution echelle spectrometer system for ICP-OES is now available from Sopra.The instrument employs pre-dispersing optics and a 1.5 m focal length echelle spectrometer with a wavelength range of 180 - 800 nm (2257). The system is controlled using an Apple IIe microcomputer programmed in BASIC and PASCAL, and single element and rapid multi-element operation modes are available. A Philips 50 MHz ICP system is used as the source. An ICP spectrometer system, Spectroflame, offering single and double polychromator options across a spectral range of 190 - 800 nm has been introduced by Spectro.A special feature of the system is the use of fibre optics for the collection of radiation from the plasma. The microprocessor data-processing and readout system provided nay be supplied separately. A range of optical emission spectrometers equipped with electrical sources are a1 so avai 1 able.Allied Analytical systems, incorporating Instrumentation Laboratory (UK) Ltd., have expanded their ICP range to include the ICAP 9000 simultaneous ICP spectrometer series previously distributed by Jarrel-Ash. The company also continue to promote the Plasma 200 system (C39, C55, C115, C339, C2457). VG Isotopes have added the VG 9000, a glow-discharge mass spectrometer to their range (C329).The system utilizes a high resolution double-focussing mass spectrometer which is required to eliminate interferences caused by molecular species produced by the source. A lower resolution spectrometer, the VG 9010, is available for less critical applications. A 2-8000 microprocessor is used for system control and the software for the instrument is written in BASIC.Both VG Isotopes (C201, C342, C1566, 1955) and Sciex (C1228, C1509, C1523, C1942) continued to promote their respective ICP-MS instruments (see ARAAS, 1983, 13, 89 and Section 1.2.1.4). 2.7.2 Absorption Varian are introducing a new range of AA spectrometers. The SpectrAA-30 is an automated AA/AE spectrometer, incorporating a 0.33 m Czerny-Turner monochromator.Instrument control and report formatting is achieved using an integrated DS-15 data station. The system has a manually operated 4-lamp turret using data encoded lamps for element identification. The SpectrAA-40 includesliistrumen tation 77 an automated 8-lamp turret and has provision for the automatic determination of up to 12 elements in sequence.The instrument may be operated with automatic flame or furnace atomizers, or a vapour generation system, all of which have been updated to be programmed directly from the data station. The system can be programmed in BASIC to enhance control and data processing packages. There is provision for automatic set-up from a cookbook or from stored user-developed methods . Perkin-Elmer have introduced the Zeeman 3030 spectrometer.This is a graphite furnace-only AA instrument equipped with a.c. Zeeman-effect background correction. The associated HGA 600 graphite furnace and AS-60 autosampler can be programmed directly from the spectrometer keyboard using cookbook information resident on floppy disks. Automatic calibration with up to 8 standards i s available and storage of a complete analytical method is possible.Hitachi have added 3 spectrometers to their Zeeman range. The 2-6000 is a dedicated flame instrument, whilst the 2-7000 i s supplied with a graphite furnace. The 2-8000 system offers a choice of atomizers. The 903 AA spectrometer, introduced by GBC, is a single-beam version of their 902 double-beam instrument. Both instruments now have interlocked gas control units and ignition systems.The new System 1000 is a modular automatic sampling device which can be used to control furnace heating, flame and furnace autosamplers, and calibration procedures. Allied Analytical Systems offer the same range of AA spectrometers, but intend to announce a new graphite furnace, the IL 755, i n 1985. The range of Pye Unicam AA equipment is unchanged.However, the company continues to promote advantages of totally pyrolytic graphite tubes for ETA-AAS (C1690, C2442) and the slotted quartz tube for FAAS (446, 1872, C332, C1605). the Other references of interest - Patents for electrothermal atomizers: 200, 201, 202, 203, 208, 209, 210, 576, 605. Patents for flame systems: 241, 486. Patents for AA spectrometers: 604, 623, 2352. 2.7.3 F1 uorescence Baird remain the only manufacturer to produce a commercial AFS system. The application o f ultrasonic nebulization for sample introduction in ICP-AFS and the use of a low pressure mercury lamp as an excitation source were amongst the developments reported in 1984 (C338, C1074, C1293, C2458. )TABLE 2.7A COMMERCIALLY AVAILABLE EMISSION SPECTROMETERS Reciprocal Wavelength Foca 1 nm p e r mm nm m Suppl i e r * Mode 1 d i s p e r s i o n / range/ l e n g t h / Type o f source ( a ) N e w e n t r i e s described i n S e c t i o n 2.7 - Phi l i p s A n a l y t i c a l PV 8050 0.46 165 - 485 1 .o Monoalternance 5 - 500 Hz h i g h r e p e t i t i o n spark, i n t e r m i t t e n t d.c.a r c PV 8055 0.46 165 - 485 1 .o as PV 8050 PV 8065 0.46 165 - 485 1 .o 50 MHz ICP, arc o r spark PV 8370 0.46 170 - 410 1 .o GDL ~ d.c.arc, p o r t a b l e d.c.arc, p o r t a b l e Spectro GmbH S p e c t r o t e s t 0.50 220 - 530 0.75 S p e c t r o t e s t J r 0.50 210 - 500 0.50 Spectrolab Vacuum 0.50 165 - 230 0.75 Spark Spectrolab A i r 0.50/0.67 210 - 800 0.75 Spark 2 f 2. Spectroi 1 0.50 210 - 800 0.75 d.c.arc K $ ? 3 -..( b ) Instruments s t i l l o f f e r e d by manufacturers"" B a i r d Corporation Spectromet 1000 0.6 o r 0.3 210 - 590 1.0 Arc o r spark, r o t a t i n g n 2 2 2 2 d i s c ; modular 190 - 295 Spectrovac 1000 0.6 o r 0.3 173 - 767 1 .o as Spectromet 1000Instrumen tation 79 Y L fa m a m r. 0 0 e Kt I 0 m r m 0 m m z a, D 0 0 c, V aJ Q m 7 '7 a, TI 0 c, 0 lx 0 c Ocf cn.mu3 W I r - O W r - s N f a m 0 L 0 W 0 N m 2 wwcncu ocuor- e m w t o I I I I 0 0 0 0 r-r-r.r- v - 7 - c W 0 --. O L n W m w e 0 N L n m v) m 0 N m m v) m 0 N m m v) fa 0 ru L n W v) m V fa > 0 -P c m 3 0 0 W Ln m 0 cu m p7 v) fa 0 N L n m v) m 0 N m m wl m 0 N Lo W v) m V > 0 c, c m 3 0 0 m m m fa Y L fa v) aJ M fa 4J 0 > n 7 _1 m 0 0 m d I 0 e cu e m 0 0 0 W W 0 0 0 W wl m 7 Lo r-. 0 0 r. W I e r-. r- e 0 L 0 Ln Ln 0 r- 0 r- m w n 0 CI Y L fa m a m 0 0 M to I 0 r. ? W Ln 0 W N m > 3 K 0 > C .r- n 0 3 a 0 H Y L a a m 0 P 0 m to I 0 r- r W Ln 0 w to e > 3 aJ M m 4 r-- If o v MU > L - a o . M- 0 - M a J . 7 -u u L- L o a J 0 3 MaJ O a J L L v) M f a aJ 8 i U L M L - v ) . r + 0 . r L - >wc, 2 2 3 f a m - P v Mca TABLE 2.7A COMMERCIALLY AVAILABLE EMISSION SPECTROMETERS (continued) 0 Supplier* Model Reciprocal Wavelength Foca 1 d i spersi on/ range/ nm per mm nm m length/ Type o f source Labtest Equipment L t d V 25 (continued) 2100 V 82 ~ 0.46 170 - 428 1.0 I Transource I 0.34 o r 0.68 185 - 680 1.0 'Transource 0.42 o r 1.68 170 - 1040 0.75 Universal source P h i l i p s A n a l y t i c a l PV 8020/01 0.46 177 - 410 1.0 Monoal ternance 50 Hz spark w i t h h i g h energy c o n d i t i o n s PV 8020/03 0.69 190 - 615 1.0 as PV 8020/01 PV 8350 vacuum 0.46 PV 8250 a i r 0.69 0.59 0.92 0.46 177 - 410 1.0 Monoal ternance 50 Hz spark, d.c.arc, GDL, HCL o r I C P 190 - 615 1.0 as PV 8350 190 - 531 190 - 820 190 - 410 PV 8270 0.55 190 - 700 1.5 as PV 8350 e b spark, a r c -. -5 s Siernans AG Spectromet 1000A 0.78 220 - 750 1.0 F l o a t i n g anode, D Spectromet IOOOV 0.36 Spectromet 1000HV 0.36 150 - 450 1.0 as f o r IOOOA 110 - 450 1.0 as f o r 1000AInstrumentation 81 VI 2 0 L 5 > .r Lo a3 0 0 e 0 I Lo r. r.- r r.N 0 e 0 e r V LI H ln W L c, m 3 -0 C .r H X W Q m Y L 5 Q m L 0 V Q Lo r. 0 N 0 0 a3 N I 0 0 cu r. m 0 L 0 rf r. 0 N In a a ro C a, 3 Lo VI W N L 5 0 M w > '7 7 W r.cu a, 7 n 5 t- c .r 8 W > M W 5 ln W ln ln W -U 75 5 h K 5 Q 0 .r 5 N r- m -I m m 0-l r y s T K 'r -0 C 3 0 Y- W n m c V ? a L LI .r c, C W E a 'r 3 W W W -!= c, Lc 0 VI t 0 4 (1 L u m a, m L W r '7 F-- r-- 3 -;82 Analytical Atomic Spectroscopy .-. M A K V .r C 4 a J L o - V L a J a J N L Q L I ool4-E c, 4 L aJ 8 aJ CI a 1 + \ 3 L Q a J 4 3 3 0 3 0 QY --. L -4 9 0 9 O K O a J LF- E --.- 8 9 O E v .- E o m L L L Q a J aJ V v ) aJ '7 E E73 K .C a a 7 aJ 73 0 E Y L a, Q Q 3 m 'r 7 N c r. N Lo 7 0 r-- m p? 0 0 m 7 L U L 9 a J m m a , aJ 'r W L 0 7 3 4 w a 'I- L - 0 a a no a 1 N c r. N Lo N I 1 /-. E 2 0 0 0 N O w f f l p? fflr. O N 0 0 u . . U W Q m 4 m m a r-. V K H m a -J 8 9 E W a, J n (u 7 r. N ffl 7 E 7 X N r.N Lo 0 L 0 m N 0 H 4 v) 9 F- a L W E W I 8 Y L aJ c .r a 0 In 0 N Lo r-- - s 0 0 m a3 0 0 W 0 0 In c v, a n lu L Cl n v, N - r. N Lo c I I aJ 5 7 l4- 0 c, 0 a, Q m F- a V 4 A a C '7 7 a 0 c, V Q v, N r- r. N Lo N L a, c, aJ 0 c, V aJ Q v) v) v) a W 0 Q 3 L -0 9 3 0 7 8 a w 7 X aJ V v, 'r N P r- N Lo c L aJ 4 aJ E L c, V Q VI v) m 4 E aJ 0 Q III L -0 a 3 0 7 U 1 0- a E a 7 a V 8 H v) 4 C m a , a J E a3 O L .Q+ o m b9K c3cT >> H HInstrumentation N r- r.N m N I I 0 0 N E v) 4 a 4 7 7 4 U c, -h 4 8 4 v) W E m a , ‘7 c, vv) - - h .I- ,--- a m N c r- N m N In r. 0 I 0 0 0 0, a 4: 0 - N c I-- N m N In r. 0 I a s U N ? r. N m ? I cn 0 0 c c u) 0 0 m m c L U rn N c r. N 0 N I cn d 0 7 7 m 0 \ W a- 0 \ m rn 0 0 N m M N 7 r- N 0 N I cn 0 0 c 7 m 0 --.W d 0 \ M cn 0 0 W ln m N 7 r- N 0 N 1 cn 0 0 P 7 M 0 --. W ‘Yt 0 \ M cn 0 0 m LD M 0 d 0 c I I m LL --. m a E 7 a c 0 c, m 0 Q L 0 0 u .r ‘? 5 m m u3 0 e L 0 N 7 r. N 0 m L 0 m N 0 c N 0 \ m M 0 --. ul u3 0 9 E L c, U v, 4 a 5 r-- a c, 5 4 U a, Q m v) 4 c, aJ 0 c, U al Q m v) 4 U > 0 c, U Q m 4 5 P- a U -0 I m b 0 r. N 0 I u3 0 0 > - c Q v) 4 L c, U a, m 4 a v) c, 8 a, 5 c, v) C U c ro E V -0 I > H v) m > t-( v) m a V cl > c 4 Q v) 5 L c, V a, Q v, N r.N 7 0 m I m c > u v) m > H v) 4 a u U > c 4 Q v) 4 L c, U a, Q m u -0 I > Y v) m > H v) 4 H > c 4 Q v) 4 L c, U a, Q v, N b N c In N m b 0 ‘Yt b 0 I In In 0 0 r. cn W 7 m U c, h ‘7 7 m a 8 L aJ M I ? ‘r N r. N c In N Lo c m c c I r. N 0 U m > h 0 0 0 0 W ? a c 3384 Analytical Atomic Spectroscopy N m W -1 4 I- W Lo N N m 0 W Lo 0 a N m 2- 3 C 0 > > I C 'r- n 0 3 W Lo N N 0 F e 0 u a co m 2- 3 W Ln N N 0 7 L aJ U 0 c, v) 7 v e 0 E I v, co m 2- 3 u3 m cu N 0 F- n L a, U 0 -0 C N co cu 0 v & X > co m 2- 3 W Ln (u N 0 F- W m 0 co e > r> W Ln N N 0 F- e 0 n N m c O > 'r- '3 c, 4 + C 'r co o m E O > u 3 >r o r r.4 > c e 3 0 v N F- r.N m c W 0 CD 0 Ln r-- C 0 Y 5 5 r a C 0 c, c 0 Y N 7 r. N ln m L 0 ln 7 Lo r. 0 L 0 W 0 Ln 0 L 0 W 0 L n m 7 C 0 Y 5 E m 4 a 7 cu c r. N N I r. m 0 0 r. C 5 u m 4 E m 5 a F- ?- c, v) a, c, 4 -J n 0 e N Ln r. 0 N W 0 Ln r. c, m aJ c, 4 5 c a N 7 r. N 0 N e 0 Lo a m 0 - . . . . > m 3 > . '7 m 0 0 m Lo 0 L o 0 W" a u v c - 5 on L aJ w I C Y L a, r-- .r aInstrumentation 85 0 Ln 0 N ln 7 to N 0 L 0 m L n 0 L 'r m 2 N co > a P a V c, 1, .r r- 0 ln 0 N 0 7 l n W m m e w ddd L L L 0 0 0 0 1 N W u 3 m e 0 0 0 .. . 0 Lo N to > a 0 Ln 0 N 0 c W e 0 5 U Kl > 0 ln M to > a N r- N 7 I ln 0 W 7 0 r. 2 v) W L c, v) 3 U C .r - X aJ Q v, N 7 h N I ln r- 0 7 c N 0 r. r- N c r. N I 0 r- to 0 e 0 h 7 N 7 h N I W N c Ln W 0 m W N 7 W h N ffl III Kl c- 7 5 .r C W > M W Kl ln ffl ln ln W -0 u >, C Kl 0..r m 5 W03 o\ TABLE 2.7C COMMERCIALLY AVAILABLE ATOMIC ABSORPTION SPECTROMETERS Supplier" Model - Single/ double beam Resolution/ Background Data o u t p u t nm c o r r e c t i o n type (a) New entries described in Section 2.7 GBC S c i e n t i f i c Pty L t d GBC 903 ( s i n g l e ) 0.2 D2 lamp RS 232C Nissei Sangyo H i t a c h i 2-6000 (double) 0.09 Zeeman e f f e c t - 2-7000 (dou b 1 e ) 0.09 Zeeman e f f e c t - 2-8000 (double) 0.09 Zeeman e f f e c t - Perkin-Elmer Zeeman 3030 (double) 0.2 Zeeman e f f e c t IEEE/RS 232C Varian Techtron P t y L t d ~ ~~ ~ SpectrAA 30 (double) SpectrAA 40 (double) 0.1 D 2 lamp 0.1 D2 lamp Centronics ( I E E E , RS 232C o p t i o n a l ) 5 e- S-12 ( s i n g l e ) 0.04 S m i th-Hi e f t j e RS 232C 3 5 Video 11 ( s i n g l e ) 0.04 S m i t h - H i e f t j e + RS 232C -.s Video 12 (double) 0.04 Smith-Hieftje + RS 232C f 2 RS 232C $ (b) Instruments still offered by manufacturers** A l l i e d A n a l y t i c a l Systems S-11 ( s i n g l e ) 0.04 Smith-Hieftje RS 232C 2. D arc 2 D arc 2 a D2 arc 2 S m i t h - H i e f t j e + Video 22 (2-channel double) 0.04B a i r d Corporation Alpha 1 ( s i n g l e ) 0.1 - B i t p a r a l l e l BCD (TTL l e v e l s ) A1 pha computer systems Alpha 2 ( s i n g l e ) 0.1 - Alpha 3 ( s i n g l e ) 0.1 D2 HCL Alpha 4 ( s i n g l e ) 0.1 D2 HCL GBC S c i e n t i f i c P t y L t d SB 900 ( s i n g l e ) 0.5 D2 lamp I E E E - 488 GBC 901 ( s i n g l e ) 0.1 D lamp I E E E - 488 2 GBC 902 (double) 0.1 D2 lamp RS 232C N i s s e i Sangyo D lamp 180-50 ( s i n g l e ) 1.2 D2 lamp 180-60 (double) 1.2 Zeeman e f f e c t 180-70 (double) 1.2 Zeeman e f f e c t - 180-80 (double) 1.2 Zeeman e f f e c t - 2 H i t a c h i 180-30 ( s i n g l e ) 1.2 - - - Perkin-Elmer 2280 ( s i n g l e ) 0.2 D2 lamp RS 232C 2380 (double) 0.2 D2 lamp RS 232C 5000 (double) 0.07 D2 o r W lamp RS 232C 2 way Zeeman 5000 (double) 0.07 Zeeman e f f e c t RS 23213 2 way 3030 (double) 0.07 D2 lamp RS 232C88 Analytical Atomic Spectroscopy n 73 3 S c, K 0 u .r v m OL W I- w ZE 0 m I- 0 w m z I- a CT 0 m m a a 52 0 r 0 I- 4 W J M -I H a H 9 5 a > 1 V w W 2z SI 8 V r- N w --1 m 2 0 N \ m L N W c,m 3 m E O o m V O cn a cn m a a 3 a a r- c\1 n N 0 A W M c v) F 'r v m m a E fa V K 3 ar h 'r n h C 4 0 3 a .r ac,N r- c,u O m N o m cn f a N c, 3 fam a n w a s ?- N n N 0 A W 7- n 3 0 73 .-.a, M S v) ,-- .r v 0 0 0 cn 3 a M 0 fa c 7 fa L 0 fa c, M ?- -r .r n c, u W cc re W c 2 a, N N N - W 3 0 73 h W > c, V aJ Le Le a, N N 4 7 n 7 .r v a X a, c, K W m .r W W W 3 a 5 7 N n N 0 0 /-. W M C v) 7 .? v 0 r- L D =l a 3 N 73 E 2= m 'r 0 N M N m w W W w 3 2 r N n N 0 A W M C v) 7 'r v In r- N r-- a a 73 c, 1 h c, a f 0 c, L V W k C fa L fa > .r V N m N m OL W W w - a E, r-- N n N 0 A W 3 0 73 7 n v m r- e c 2 OD 0 M - o r 0 - c f a f a C f a > > o E - 0 1 0 - 0 v) a .r E, -' 7 N 0 I n W M C v) 7 'r v z m 3 a a fa C W '> v) m 'r a, N r-- L a 0 m W > --.> 3 I - a, M 7 c v) 7J c 4 W 'r 7 n 3 0 U m m v a a W r.cu W r- n Q + c .r C a, > Do W 4 v) a, m m W U 7J h C .r m a 0 V -x *TABLE 2.7D COMMERCIALLY AVAILABLE ELECTROTHERMAL ATOMIZERS AND AUTOSAMPLERS g Suppl i e r * Model Type Control u n i t ( a ) New e n t r i e s described i n S e c t i o n 2.7 GBC S c i e n t i f i c Pty System 1000 Flame o r furnace Microprocessor c o n t r o l system f o r programming t h e autosampler GBC g r a p h i t e furnace and autosampler; c a p a c i t y f o r up t o 10 programmes; seven-step programme f o r sampling P e r k i n-Elmer HGA 600 Graphite furnace Version o f HGA 500 I E E E c o n t r o l l e d from spectrometer o r computer AS-60 HGA autosampler A l l autosampler f u n c t i o n s are c o n t r o l l e d d i r e c t l y from t h e spectrometer o r e x t e r n a l computer; operates w i t h t h e HGA 600 furnace Varian Techtron P t y GTA-96 PSC-56 Graphite furnace Updated v e r s i o n o f GTA 95 furnace f o r compati b i 1 i t y w i t h SpectrAA range Autosampler Updated v e r s i o n o f PSC 55 autosampler f o r c o m p a t i b i l i t y w i t h SpectrAA range ( b ) Instruments s t i l l o f f e r e d b y manufacturers** A l l i e d A n a l y t i c a l Systems 655 Graphite furnace Programmable 6 stages, ramp o r step heating, auto-clean, d i s p l a y o f actual temperature i n "C; temperature feedback system FASTAC I1 Flame o r furnace Aerosol deposition, d i g i t a l t i m e r s f o r sample autosampler deposition, remote t r i g g e r i n g c i r c u i t r y f o r autozeroing and a u t o c a l i b r a t i n g t h e spectrometer\D 0 TABLE 2.7D COMMERCIALLY AVAILABLE ELECTROTHERMAL ATOMIZERS AND AUTOSAMPLERS (continued) Suppl i e r * Model Type Control u n i t B a i r d Corporation A1 70 Graphite r o d Programmable, dry, ash ( 2 stages), atomize, max.temp. 3500 "C GBC S c i e n t i f i c P t y GF 900 Graphite furnace 4 temperature cycles (dry, ash 1, ash 2, atomize), temperature and ramp c a p a b i l i t i e s on each cycle: continuous d i g i t a l temperature readout H i l g e r A n a l y t i c a l HI475 Graphite furnace Programmable, dry, ash, w a i t , atomize: max.temp. 2600 "C: c u r r e n t s t a b i 1 i z e d Perki n-Elmer HGA 300 Graphite furnace Microprocessor u n i t provides up t o 8 steps o f c o n t r o l l e d heating.Control f u n c t i o n s programmed v i a keyboard: temperature, time, ramp, h o l d gas f l o w : maximum power heating HGA 400 Graphite furnace As HGA 300 b u t w i t h spectrometer c o n t r o l f u n c t i o n s and d i g i t a l d i s p l a y s o f temperature, time and program status: h e a t i n g r a t e o f 2000 "C s-' between any two temperatures HGA 500 AS 40 AS 50 Graphite furnace As HGA 400 b u t w i t h 9 steps o f c o n t r o l l e d heating; 6 programs can be stored and r e c a l l e d using magnetic cards Furnace Automatic i n s e r t i o n o f up t o 35 standards: autosampler methods o f a d d i t i o n , m a t r i x m o d i f i c a t i o n Flame or I C P Microprocessor c o n t r o l l e d u n i t : programmable autosampler functions: carousel c o n t a i n i n g 50 sample tubes (15 m l ) bPye Unicam Video furnace Graph SP-9 furnace Graph t e furnace t e furnace SP-9 furnace Autosampler autosampler Microprocessor c o n t r o l o f 6 phases and ramps t o 3000 "C; v o l t a g e o r temperature c y n t r o l : 18 ramp rates, 9 l i n e a r , 2 - 2000 "C s and 9 exponential: n o n - v o l a t i l e storage o f 10 programmes 4 phases each programmable t o 3000 "C; v o l t a g e o r temperature c o n t r o l : 9 ramp r a t e s 2 - 2000 "C s - l : d i g i t a l parameter s e l e c t i o n and d i s p l a y Automatic sampler takes 38 samples and 2 wash p o s i t i o n s : i d e n t i f i e s blanks, samples and standards: s e l e c t i o n o f number o f r e p l i c a t e s and volume f o r each sample Sh i madzu GFA 4A Graphite furnace Programmable, dry, ash, atomi ze: max.temp. 3000 "C: temperature monitor w i t h c o n t r o l loop: 9 ramp steps a v a i l a b l e : can s t o r e up t o 9 programmes Varian Techtron P t y L t d GTA 95 PSC 55 Graphite furnace Programmable temperature range 20 - 3000 "C: up t o 20 temperature fteps: programmable h e a t i n g r a t e t o 2000 "C s- : heat i n j e c t i o n from 40 - 150 "C Autosamp 1 e r Blank, 5 standards, 45 samples and chemical m o d i f i e r : programmable from 2 - 70 u l samples: 4 s o l u t i o n s can be dispensed t o g e t h e r Flame autosampler Microprocesor c o n t r o l l e d autosampler w i t h 5 standard and 67 sample p o s i t i o n s : keyboard programme e n t r y ~ ~~ *Company addresses are given i n Table 2.7E. * * F u l l e r d e s c r i p t i o n s o f t h e equipment i n ( b ) can be found i n ARRAS, 1983, 13, 86.92 Analytical Atomic Spectroscopy TABLE 2.7E Company A l l i e d A n a l y t i c a l Systems, One B u r t t Road, Andover, MA 01810, U. S.A. ARL Applied Research Laboratories SA, En V a l l a i r e , 1024 Ecublens, Switzerland. B a i r d Corporation, 125 Middlesex Turnpike, Bed f o r d , MA 01730, U. S.A. Beckrnan Instruments Inc.. Campus Drive, Jambouree Boulevard, Box C19600, CA 92713, U. 8. A. ADDRESSES OF INSTRUMENT COMPANIES U.K. Agent Instrumentation Laboratory (UK) Ltd., K e l v i n Close, Birchwood Science Park, Warrington, Ches h i re. ARL Applied Research Laboratories, W i ngate House, W i ngate Road, Luton LU4 8PU. B a i r d Atomic Ltd., 4 Warner Drive, Springwood I n d u s t r i a l Estate, B r a i ntree, Essex CM7 7YL. Beckman-RIIC Ltd., Progress Road, Sands I n d u s t r i a1 Estate, High Wycombe, Bucks HP12 4JL. GBC S c i e n t i f i c Equipment Pty. Ltd., EDT Research, 7/63 Park Drive, Danedong London PJWlO 7LU. Vic. 3175, A u s t r a l i a . 14 Trading Estate Road, H i l g e r A n a l y t i c a l Ltd., Westwood, Ma rgate, Kent CT9 4JL U. K. Jobin-Yvon, D i v i s i o n d ' Instruments, 16-18 Rue du Canal, 91160 Longjumeau, France. Kontron GmbH, PO Box 8057, Oskar-von-Miller S t r . 1, 8057 Eching b. ?.lunchen, West Germany. EDT Research, 14 Trading Estate Road, London NW14 7LU. L i n t o n Instrumentation, Hysol, Harlow, Essex CM18 642.lnstrurnen tation 93 Labtest Equipment Ltd., 11823 La Grange Avenue, Los Angeles, CA 90025, U. S. A. Leeman Labs Inc., 600 S u f f o l k Street, Lowel 1, MA 01854, U.S.A. Nissei Sangyo (America) Co. Ltd., ( H i t a c h i ), 460E M i d d l e f i e l d Road, Mountain View, CA 94043, U.S.A. Perkin-Elmer Corporation, Spectroscopy D i v i s i o n , 901 Ethan A l l e n Highway, Ridgef i e l d , CT 06377, U. S. A. Phi 1 i p s I n d u s t r i e SA, Spectrochemistry Department, 131 Boulevard de l'Europe, B-1301 Wavre, B e l g i um. Pye Unicam Ltd., York Street, Cambridge CB1 2Px. Sciex, 55 Glencameron Road, T h o r n h i l l , O n t a r i o L3T IP2, Canada. Scintrex, 22 Sn i d e r c r o f t Road, Concord, Ontario L4K 1B5, Canada. Techmation Ltd., 58 Edgware Way, Edgware, Middlesex HA8 8SP. Leeman Labs Inc., 59/61 Gui l d f o r d Street, Luton LU1 2NL, Beds. N i s s e i Sangyo Co. Ltd., London Road, Sutton I n d u s t r i a l Park, Reading RG6 l A Z , Berks. Perkin-Elmer Ltd., Post O f f i c e Lane, Beaconsfield, Bucks HPO 1QH. P h i l i p s A n a l y t i c a l Department, Pye Unicam Ltd., York Street, Cambridge CB1 2PX. Techmation Ltd., 58 Edgware Way, Edgware, Middlesex HA3 8SP.94 Analytical Atomic Spectroscopy Siemans A.G., Infoservice 213-71e, Postfach 156, 8510 Fijrth, West Germany. Shimadzu (Europa) GmbH, Acker Strasse 111, D-4000 Dusseldorf 1, West Germany . Spectro GmbH, Bosch Strasse 10, D-4190 K1 eve, Mest Germany. Spex Industries Inc., 3880 Park Avenue, Edd i son, NJ 08820, U. S.A. Sopra, 68 Rue Pierre Joigneaux, F9 2270 Bois-Colombes, France. Varian Techtron Pty. Ltd., 679-701 Springvale Road, Mulgrave, Vic. 3170, Australia. VEB Carl Zeiss Jena, Carl Zeiss Str. 1, 6900 Jena, GDR VG Instruments Inc., Inorganic Division, 300 Broad Street, Stamford , CA 06901, U. S. A. V.A. Howe & Co. Ltd., 12-14 St. Anne's Crescent, London SW18 2LS. Spectro Analytical (UK) Ltd., Green Lane, Churt, Far n ham, Surrey GUlO 2LT. Glen Creston Instruments, 16 Dalston Gardens, Stanmore, Middlesex HA7 1DA. Varian Associates Ltd., 28 Manor Road, Walton on Thames, Surrey KT12 2QK. Carl Zeiss Scientific Instruments Ltd., PO Box 43, 2 Elstree Way, Boreham Wood, Herts WD6 1NH. VG Isotopes Ltd., Ion Path, Road Three, W i nsf ord, Cheshire CW7 3BX.

ISSN:0306-1353    

DOI:10.1039/AA9841400053

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

CHAPTER 3 Methodology 3.1 NEW METHODS The aim o f t h i s s e c t i o n i s t o summarize t h e various new procedures and methods o f a n a l y s i s t h a t have appeared i n t h e l i t e r a t u r e i n t h e past year. As f a r as possible. papers d e s c r i b i n g new methodology which has d i r e c t relevance t o r o u t i n e a n a l y s i s have been emphasized. Many o f t h e papers described s p e c i f i c applications, e.g., i n t h e c l i n i c a l o r environmental f i e l d s , b u t t h e basic approach may be a p p l i c a b l e t o other areas w i t h o n l y minor changes. 3.1.1 Sample Preparation I n most l a b o r a t o r i e s sample preparation i s t h e most labour-intensive p a r t o f t h e a n a l y t i c a l procedure; however, few r e p o r t s have appeared on t h e s u b j e c t o f automated sample preparation. A microprocessor c o n t r o l l e d automated device was described (C1344) f o r t h e d i s s o l u t i o n ( f u s i o n ) o f powders f o r AAS o r I C P analysis. 85% LiB02) i n a glassy carbon c r u c i b l e . This c r u c i b l e was placed i n s i d e a P t c r u c i b l e which was then a u t o m a t i c a l l y moved i n t o a h i g h frequency i n d u c t i o n furnace.t h e f u s i o n ( 4 min a t 1100 "C) t h e complete furnace was moved t o generate a s w i r l i n g o f t h e f l u x f o r mixing purposes. A f t e r f u s i o n t h e sample was t r a n s f e r r e d a u t o m a t i c a l l y i n t o a beaker c o n t a i n i n g c o l d water and a magnetic s t i r r e r .A 10 m l a l i q u o t o f HC1 was added and t h e s o l u t i o n heated f o r 3 t o 5 min; when cool t h e s o l u t i o n was d i l u t e d t o 500 m l . The automated sample preparation device was evaluated by the determination o f A l l Ca, C r , Cu, Fe, Mg, Mn, P, S i and T i i n i r o n ore, s l a g and b l a s t furnace dust CRMs. Acceptable accuracy was demonstrated.The a p p l i c a t i o n o f r o b o t i c s i n automated sample preparation has been discussed by a number o f workers (C1319, C1455. C1492). The sample (0.25 g) was mixed w i t h 1.5 g of f l u x (15% H3B03 and During An improvement t o t h e basic d i g e s t i o n bomb method has been described (977). The sample was i n s e r t e d i n t o a small PTFE screw cap v i a l which was placed i n s i d e t h e o u t e r PTFE vessel.No losses o f As o r Hg were reported during decomposition o f b i o l o g i c a l CRMs and contamination was reduced. The major disadvantage was t h a t t h e i n n e r v i a l had t o be replaced a f t e r 4 o r 5 d i g e s t i o n s under pressure, which was considered c o s t l y . A number o f papers have appeared t h i s year on the use o f domestic pressure cookers as an a l t e r n a t i v e t o expensive s t e e l pressure-bombs (C65, C1227, 2633).It was suggested t h a t d i g e s t i o n 9596 Andy tical A tomic Spectroscopy f a c i l i t i e s e q u i v a l e n t t o 10 s t e e l pressure-bombs c o u l d be o b t a i n e d from one 3-quart pressure cooker, w i t h o n l y minor m o d i f i c a t i o n s .The p r e s s u r e cooker was a p p l i e d t o a wide s e l e c t i o n o f sample forms which d i d n o t r e q u i r e h i g h pressure f o r d i g e s t i o n ( b i o l o g i c a l s. cerami c s , geol o g i ca 1 s, organics, r e f r a c t o r i e s , sewage and sludges). A r e v i e w on a c i d pressure decomposition was p u b l i s h e d (1417) and i s recommended r e a d i n g f o r t h e a n a l y s t new t o t h i s s u b j e c t .S i m i l a r l y , a r e v i e w on t h e r o l e o f sample decomposition (1416) i n t r a c e element a n a l y s i s i s recommended. A number of r e p o r t s have appeared on sample p r e p a r a t i o n procedures a p p l i e d i n t h e d e t e r m i n a t i o n o f t r a c e elements i n foods.Woo and Ryoo (225) compared d r y , HN03/H2S04, and aqua r e g i a ashing methods f o r t h e d e t e r m i n a t i o n o f Ca, Cu, Fe, K, Mg, Fln, Na, and Zn i n h i g h - f a t f i s h t i s s u e . For t h e d e t e r m i n a t i o n o f Ca, Clg and Zn, t h e aqua r e g i a and d r y ashing methods produced s u p e r i o r r e s u l t s compared t o t h e HN03/H2S04 method.The t h r e e methods gave s i m i l a r r e s u l t s f o r t h e o t h e r elements. The aqua r e g i a d i g e s t i o n method was recommended f o r s a f e t y , r a p i d i t y , simp1 i c i t y and c o s t c o n s i d e r a t i o n s . Wet o x i d a t i o n , d r y ashing and a c i d e x t r a c t i o n methods a p p l i e d i n t h e d e t e r m i n a t i o n o f heavy metals i n foods were reviewed (1071).Ashing w i t h a r.f. (27.12 MHz) oxygen plasma was r e p o r t e d (578). Decomposition was performed i n a q u a r t z vessel equipped w i t h a c o o l i n g f i n g e r . V o l a t i l e elements l i k e As, Sb. and Se were q u a n t i t a t i v e l y recovered by r e f l u x i n g t h e d i g e s t i n 1 - 2 m l o f h i g h - p u r i t y a c i d .A 1 g sample mass c o u l d be t o l e r a t e d and even d i f f i c u l t o r g a n i c samples such as charcoal, g r a p h i t e . and p l a s t i c s (s, PTFE) were ashed w i t h o u t any problems i n a r e l a t i v e l y s h o r t t i m e . Recoveries were checked by t h e a n a l y s i s o f 6 CRMs f o r t h e elements A l , As, Cd, Co, C r , Cu, Fe, Mn, N i , Pb, Sb, Se, V, and Zn.It was claimed t h a t t h e advantages o f t h e procedure were u n i v e r s a l a p p l i c a b i l i t y , q u a n t i t a t i v e r e c o v e r y o f many elements, speed, and low blanks. O t h e r r e f e r e n c e s o f i n t e r e s t - Comparison o f a c i d d i g e s t i o n procedures w i t h and w i t h o u t HF f o r t h e d e t e r m i n a t i o n o f heavy m e t a l s i n c o a l f l y ash by AAS: 886.C r i t i c a l e v a l u a t i o n o f sample d i s s o l u t i o n techniques and a p p l i c a t i o n of ICP-OES t o t h e a n a l y s i s o f g e o l o g i c a l and b r i n e samples: C1312. Sample p r e p a r a t i o n and p r e s e n t a t i o n f o r simultaneous multi-element, ETA-AAS: C1537. Sample p r e p a r a t i o n methods and s e p a r a t i o n methods i n t h e a n a l y s i s o f environmental and b i o l o g i c a l m a t e r i a l s : C336. 3.1.2 Separation and P r e c o n c e n t r a t i o n The d e t e r m i n a t i o n o f t r a c e elements i n sea-waters by ETA-AAS i s s u b j e c t t o severe m o l e c u l a r background and chemical i n t e r f e r e n c e e f f e c t s caused by t h e h a l i d e - r i c h m a t r i x .One way t o separate t r a c e elements from t h e s a l t m a t r i x i sMethodology 97 t o make use o f c h e l a t i n g r e s i n s (see ARAAS, 1981, 11, 81). A l k a l i and a l k a l i n e e a r t h elements can be s e l e c t i v e l y e l u t e d from t h e r e s i n u s i n g an a c e t a t e b u f f e r . Metals r e t a i n e d by t h e r e s i n can then be e l u t e d w i t h d i l u t e HN03.F i g u r a & - a l . (C1592) r e p o r t e d t h e a p p l i c a t i o n o f t h i s t e c h n i q u e t o s a t u r a t e d s o l u t i o n s o f ammonium dihydrogen phosphate , ammonium sulphate, c a l c i u m n i t r a t e , and sodium c h l o r i d e . experiments were c a r r i e d o u t by s p i k i n g t h e above samples w i t h ppb l e v e l s o f Ag, Be, Cd, C r , Cu, Hg, Ni, Pb, and Zn. Recoveries were n e a r l y q u a n t i t a t i v e w i t h t h e e x c e p t i o n o f Ag, Be, and C r .Jones (C1365) i n v e s t i g a t e d t h e i n f l u e n c e o f pH and d i g e s t i o n c o n d i t i o n s on t h e s e p a r a t i o n o f t r a c e elements f r o m t i s s u e d i g e s t s on a Chelex-100 column, p r i o r t o ICP-OES d e t e r m i n a t i o n .Q u a n t i t a t i v e r e t e n t i o n and r e c o v e r y were o b t a i n e d f o r Cd, Cu, Fe, Mo, and N i i n a wide v a r i e t y o f p l a n t and animal t i s s u e CRMs. T h i s precedure a l s o reduced s p e c t r a l i n t e r f e r e n c e and n e b u l i z e r i n s t a b i l i t y problems caused by h i g h c o n c e n t r a t i o n s o f a l k a l i and a l k a l i n e e a r t h elements. Recovery D e t a i l s o f a comprehensive s t u d y on t h e s o l v e n t e x t r a c t i o n of t r a c e elements from n a t u r a l waters and sea-waters were r e p o r t e d (1042).Trace elements were e x t r a c t e d w i t h APDC and hexamethyleneammonium hexamethylene- d i t h i o c a r b a m a t e i n xylene, and determined by ICP-OES.Operating c o n d i t i o n s f o r Cd, Co, C r , Cu, Fe, Mn, Mo, N i , Pb, V, and Zn were e s t a b l i s h e d . C a l i b r a t i o n graphs were l i n e a r up t o 30 ng m l - ' f o r each element and t h e d e t e c t i o n l i m i t s ranged from 17 pg m l - 1 f o r Cd t o 0.5 ng rn1-l f o r Pb.The i n f l u e n c e of pH d u r i n g t h e e x t r a c t i o n procedure and t h e s t a b i l i t i e s o f t h e metal complexes i n t h e o r g a n i c phase were a l s o discussed. Traces o f V i n petroleum and petroleum d e r i v a t i v e s were determined b y FAAS u s i n g t h e i o n - p a i r e x t r a c t i o n technique (794). The V-benzohydroxarnic a c i d complex was e x t r a c t e d a t pH 4.7 i n t o e t h y l acetate.The o r g a n i c phase was t h e n n e b u l i z e d i n t o a N20/C2H2 flame. The c a l i b r a t i o n c u r v e was l i n e a r up t o 15 mg 1-I, w i t h a s e n s i t i v i t y o f 0.03 mg 1-'. An o n - l i n e t r a c e metal enrichment system was developed (2154) f o r t h e d e t e r m i n a t i o n o f Cd, Co.Cu. N i , Pb, and Zn i n t a p water. A column c o n t a i n i n g immobilized 8 - q u i n o l i n o l was used i n a F I system. A l l metal i o n s were q u a n t i t a t i v e l y recovered a t an uptake pH o f 6.5. A v a r i a b l e column i n j e c t i o n d e v i c e was used i n t h e f l o w system i n o r d e r t o i n c r e a s e o r decrease t h e c o n c e n t r a t i o n f a c t o r .A l l o p e r a t i o n s i n c l u d i n g b u f f e r a d d i t i o n s were made o n - l i n e and t h e trapped i o n s were e l u t e d w i t h 400 u1 o f a c i d and swept d i r e c t l y i n t o t h e n e b u l i z e r o f a flame AA spectrometer. The method was compared w i t h ETA-AAS f o r Cu i n t a p water samples. The two methods gave e q u i v a l e n t r e s u l t s b u t t h e F I system was more r a p i d and p r e c i s e .The number o f p u b l i c a t i o n s r e p o r t i n g t h e use o f f l o t a t i o n t o separate and p r e c o n c e n t r a t e t r a c e elements has increased. C o - p r e c i p i t a t i o n w i t h c o b a l t p y r r o l i d i n e d i t h i o c a r b a m a t e (1043) was employed i n t h e d e t e r m i n a t i o n o f Ag i n sea-water by ETA-AAS.A 200 m l sample was a c i d i f e d t o pH 1.9 w i t h HN03 and98 Analytical A tomic Spectroscopy then t r e a t e d w i t h 200 mg 1-I o f C O ( N O ~ ) ~ and 1 m l o f 2% m / V APDC. The r e s u l t i n g p r e c i p i t a t e was c o l l e c t e d on a polycarbonate membrane f i l t e r , t r e a t e d w i t h 210 u1 o f concentrated HN03, and evaporated t o dryness under an i n f r a r e d lamp. The residue was then dissolved i n 2 m l o f a s o l u t i o n c o n t a i n i n g 0.2% m l V (NH4)H2P04 and 5% V / V HN03.A 25 u1 a l i q u o t was then i n j e c t e d i n t o a g r a p h i t e furnace f o r Ag determination. Recoveries o f 92 t o 95% were reported, f o r Ag a d d i t i o n s o f 0.01 t o 1 pg l-’, and t h e d e t e c t i o n l i m i t claimed was 1-l.It was a l s o reported t h a t Cd, Cu, N i , and Pb were co-precipitated w i t h Ag. The preconcentration o f Sc from aqueous s o l u t i o n s by means o f t h e absorptive bubble technique was reported (1013). Samples were t r e a t e d w i t h Fe(OH)3 (as a t r a c e element gatherer) and Na o l e a t e (as s u r f a c t a n t ) and N2 was bubbled through t h e s o l u t i o n .Traces o f Sc (0.4 - 40 ppb) were c o l l e c t e d i n t h e f r o t h . r e d i s - solved, and determined by ETA-AAS. 0.1 ng 3.1.3 Sample I n t r o d u c t i o n 3.1.3.1 S o l i d Sample I n t r o d u c t i o n The technique i n t h i s area t h a t received most a t t e n t i o n was t h e i n t r o d u c t i o n o f s l u r r y samples i n t o ICPs (see a l s o Section 1.2.1.2).flame AA systems, o r g r a p h i t e furnaces. A fundamental study was conducted (C1489) t o e s t a b l i s h t h e effects of p a r t i a l analyte s o l u b i l i z a t i o n , s l u r r y p a r t i c l e size. aerodynamic mass t r a n s p o r t e f f i c i e n c y and p a r t i c l e v a p o r i z a t i o n k i n e t i c s on t h e accuracy o f t h e procedure.Methods used i n t h i s study included l a s e r d i f f r a c t i o n techniques and photon c o r r e l a t i o n spectroscopy. A s p e c i a l i z e d g r i n d i n g technique was discussed which produced p a r t i c l e sizes o f 6 um o r l e s s from coal and o t h e r geological samples w i t h g r i n d i n g times o f o n l y 10 min.Ebdon and Gray (C2477) reported the determination o f A l , C r , Cu, Fe, Ng, Mn, Na, N i , and Zn i n c l a y s by s l u r r y n e b u l i z a t i o n i n t o an I C P . Clay suspensions were prepared over a concentration range o f 0.5 t o 20% m/y t o enable t h e determination o f major and t r a c e elements by d i r e c t s l u r r y atomization.It was reported t h a t t h e plasma atomization o f t h e s l u r r y was 50% o f t h a t o f aqueous s o l u t i o n s o f an equivalent concentration. Use o f t h e S i content o f t h e k a o l i n as an i n t e r n a l standard and simple aqueous standards y i e l d e d acceptable accuracy. This approach worked w e l l f o r a l l elements except Fe and Na. A d d i t i o n o f an aqueous s o l u t i o n o f NH t o t h e c l a y s l u r r y (as a dispersant) improved t h e atomization e f f i c i e n c y Watson and Moore (2397) concentrated Au, Pd, P t , Rh.and Ru on an ion-exchange r e s i n (Monivex), formed a s l u r r y by mixing w i t h H20, and nebulized t h e s l u r r y i n t o an I C P f o r analysis. It was suggested t h a t t h e ICP-resin technique was adequate f o r t h e a n a l y s i s o f t r a c e noble metals i n ores and t a i l i n g s i f a sample o f 500 g was taken. I n a s i m i l a r method (C1684) t h e r e s i n s l u r r y was i n j e c t e d i n t o a g r a p h i t e furnace f o r t h e AA 3 which approached 100% f o r Mg.Methodology 99 determination o f Au, Ir, Pd, P t and Rh.Fagiolo and Landi (685) described a simple method which involved t h e n e b u l i z a t i o n o f a carbonaceous s l u r r y f o r t h e FAAS determination o f Ca, Cd, Cu, Fe, K, Mg, Mn, and Zn i n vegetable f o o d s t u f f s .The s l u r r y was obtained by warming t h e sample i n H SO and d i l u t i n g w i t h H20. Accuracy o f k5% was obtained f o r various organic CRMs and p r e c i s i o n was i n t h e region o f 4%.Simultaneous multi-element ETA-AAS was a p p l i e d (C1224) t o t h e determination o f A l , Co, Cr, Cu, Fe, Mn, Mo, N i , Pb, Sn, V, and Zn i n s l u r r i e s prepared from several b i o l o g i c a l CRMs. Average accuracies were approximately 100 f 7% w i t h sample sizes as small as 10 mg. U l t r a s o n i c homogenization was used t o prepare a s l u r r y from r i v e r sediments (298).Precisions o f about 10% were obtained f o r Ca, Cd, C r , N i , and Pb when t h e s l u r r y was analysed by ETA-AAS. A severe m a t r i x i n t e r f e r e n c e was reported f o r Zn. The accuracy o f t h e method was demonstrated i n comparison w i t h r e s u l t s obtained by a conventional HN03/HC104 wet d i g e s t i o n FAAS method. H i e f t j e (C1491, see a l s o ARAAS, 1982, 11. 16). i n a conference report, presented two new devices f o r h i g h e f f i c i e n c y micro-sampling o f s o l i d s and l i q u i d s . The f i r s t device was termed a 'microarc', which was e s s e n t i a l l y an atmospheric-pressure glow discharge. The device was capable o f handling m i c r o l i t r e s i z e a l i q u o t s o f sample solutions, o r conductive s o l i d s .The samples could be atomized q u i c k l y and completely f o r i n t r o d u c t i o n i n t o a v a r i e t y o f e x c i t a t i o n sources o r atom c e l l s (MIPS, micro-ICPs, conventional ICPs and after-glow plasmas). The second approach was termed a 'radiofrequency a r c ' . This was based on t h e f a c t t h a t a grounded e l e c t r o d e placed a t t h e base o f an I C P draws a p o r t i o n o f I C P energy t o it.The r.f. arc can sample d i r e c t l y m a t e r i a l s such as a l l o y s and non-conductive samples which have been mixed w i t h C and placed on a conductive support. It was suggested t h a t more work i s necessary t o c h a r a c t e r i z e f u l l y t h i s device, b u t i t was thought t h a t i t o f f e r e d e x c i t i n g p o s s i b i l i t i e s f o r s o l i d sampling i n t o t h e ICP. 2 4 Other references o f i n t e r e s t - Analysis o f s o l i d samples using Zeeman-effect AAS: C1225. Method f o r a n a l y s i s o f r o l l i n g - m i l l products w i t h o u t sampling (mobile spectrometer): 2209. D i r e c t i n t r o d u c t i o n o f powder samples i n ICP-OES: C1440. 3.1.3.2 L i q u i d Sample I n t r o d u c t i o n This year has seen an increase i n t h e number o f p u b l i c a t i o n s on f l o w i n j e c t i o n ( F I ) procedures (see a l s o Section 1.2.1.2). It was suggested (1254, C2421, C2436) t h a t t h e advantages o f F I included on-line sample d i l u t i o n , a d d i t i o n o f reagents, s o l v e n t e x t r a c t i o n c a p a b i l i t i e s , hydride generation, preconcentration on resins, and removal o f c e r t a i n interferences.It was demonstrated t h a t F I100 Analytical Atomic Spectroscopy c o u l d be used t o extend t h e l i n e a r range o f c a l i b r a t i o n by measurement o f t h e peak w i d t h (846) s i n c e t h e peaks were e x p o n e n t i a l i n shape.It was suggested, however, t h a t t h e peak w i d t h method was n o t as a c c u r a t e as t h e c o n v e n t i o n a l method. A1 though F I procedures have been a p p l i e d t o s e v e r a l appl i c a t i o n areas, c l i n i c a l a p p l i c a t i o n s have r e c e i v e d most a t t e n t i o n . McLeod e t a l . (876) r e p o r t e d t h e simultaneous multi-element a n a l y s i s o f blood serum by FI-ICP-OES.The serum was d i l u t e d 1 + 1 t o e l i m i n a t e i n t e r f e r e n c e s and i t was p o s s i b l e t o determine Ca, Cu, Fe, K, Mg, Na, and Zn i n 20 p1 o f sample. A FI-AAS method was devised (1471) f o r t h e d e t e r m i n a t i o n o f Zn i n serum. Samples were d e p r o t e i n i z e d w i t h TCA and i n t r o d u c e d v i a a 0.5 mm i.d.PTFE tube. Up t o 180 samples p e r hour c o u l d be handled and RSDs o f 3 - 4% were achieved a t Zn l e v e l s i n normal serum samples. A FI-ICP-MS technique (C2454) was used f o r t h e d e t e r - m i n a t i o n o f A l , As, Cd, C r , I, Fln, No, Pb, Se, and V i n serum. A t p r e s e n t t h i s work i s a t an e a r l y stage; however, t h e p r o s p e c t s f o r t h i s t e c h n i q u e l o o k promising.A d d i t i o n a l r e f e r e n c e s on t h e preceding t o p i c - 564, 775, C1535, 1865, 2361, 2547, 2550. Samples and standards were prepared as emulsions (1792) f o r t h e d e t e r - m i n a t i o n o f Cu and Fe i n MIBK e x t r a c t s o f APDC complexes.M a j o r advantages o f t h i s approach were t h a t aqueous standards c o u l d be used f o r c a l i b r a t i o n w h i l s t t h e presence o f t h e o r g a n i c phase enhanced t h e FAAS s e n s i t i v i t y . A f u r t h e r advantage claimed was t h a t t h e s t a b i l i t y o f t h e e x t r a c t increased, i n t h e case o f Fe from 2 hours t o 3 weeks, i n t h e w a t e r / o r g a n i c emulsion.The determin- a t i o n o f t h e t o t a l Fe c o n t e n t o f used l u b r i c a t i n g o i l s by AAS was r e p o r t e d (1266). A 1 g a l i q u o t o f o i l was mixed w i t h 2.5 m l o f a s o l u t i o n c o n t a i n i n g HF and HN03 ( 1 + 1 ) i n a capped p o l y e t h y l e n e b o t t l e f o r 5 min t o Fe p a r t i c l e s w i t h o u t d e s t r o y i n g t h e o r g a n i c m a t r i x .The p r o d u c t was shaken w i t h 3 m l MIBK, 10 m l o f aqueous 20% Nemol K39 and 25 m l of H20. The emulsion was i n t r o d u c e d i n t o an air/C2H2 flame f o r d e t e r m i n a t i o n o f Fe a t 248.3 nm. The method was r e p o r t e d t o be simple, r a p i d , and accurate, and was unaffected by t h e p a r t i c l e s i z e o f d i s p e r s e d s o l i d s .Comtois and Kinsey (C90, C125) r e p o r t e d t h e a p p l i c a t i o n o f e m u l s i f i e r s t o organic/aqueous m a t r i c e s f o r DCP a n a l y s i s . T h i s approach was adopted s i n c e many o r g a n i c compounds used f o r d i l u t i o n o f o r g a n i c samples c o u l d n o t be o b t a i n e d w i t h o u t s i g n i f i c a n t contamination.Data presented i n c l u d e d f i g u r e s o f m e r i t , s h e l f l i f e , s e n s i t i v i t y and optimum o p e r a t i n g parameters f o r t h e d e t e r m i n a t i o n o f t r a c e elements i n v a r i o u s o r g a n i c samp 1 es . d i s s o l v e t h e A novel approach t o l i q u i d i n t r o d u c t i o n i n t o an I C P was r e p o r t e d (C2537).The sample was i n j e c t e d o n t o a W w i r e and d i r e c t l y i n s e r t e d i n t o an ICP. D e t e c t i o n l i m i t s o f 0.2 and 0.08 ng m1-I were o b t a i n e d f o r Cu and Zn, r e s p e c t i v e l y .Methodology 101 3.1.3.3 Gaseous Sample I n t r o d u c t i o n Although continuous f l o w h y d r i d e systems have been used i n ICP-OES f o r many years, t h e move t o t h e AAS t e c h n i q u e is r e l a t i v e l y new. Numerous a p p l i c a t i o n s o f automated continuous f l o w h y d r i d e systems f o r AAS were reported, t h e m a j o r i t y b e i n g conference papers presented by i n s t r u m e n t manufacturers (1059, C1510, C1514, C1615, C1674, C1683. 1759, 1840, 2058. C2434, C2460) (see a l s o Sections 1.5.1 and 2.4).A p p l i c a t i o n s s t u d i e s i n t h e r e f e r e n c e s c i t e d i n c l u d e d b i o l o g i c a l , environmental and g e o l o g i c a l samples. Improvements i n p r e c i s i o n a r e achieved i n continuous f l o w systems due t o t h e p o s s i b i l i t y o f s i g n a l i n t e g r a t i o n which g i v e s b e t t e r d e t e c t i o n l i m i t s i n c o n c e n t r a t i o n terms over d i s c r e t e systems.Welz and Melcher (2331, 2332, 2334) c o n t i n u e t o make s i g n i f i c a n t c o n t r i b u t i o n s t o t h e understanding o f i n t e r f e r e n c e mechanisms i n h y d r i d e g e n e r a t i o n (see a l s o S e c t i o n 1.5.1). The i n t e r f e r e n c e o f Co, Cu, Fe, and N i on t h e d e t e r m i n a t i o n o f Se was i n v e s t i g a t e d (2331).The H2Se was generated i n a pure a c i d s o l u t i o n and was bubbled through a second s o l u t i o n c o n t a i n i n g i n t e r f e r e n t p r i o r t o a t o m i z a t i o n by c o n v e n t i o n a l means. A l l elements i n v e s t i g a t e d caused an i n t e r f e r e n c e , b u t an i n c r e a s e i n a c i d i t y o f t h e i n t e r f e r e n t s o l u t i o n reduced t h e e f f e c t , due t o t h e enhanced s o l u b i l i t y o f t h e reduced metal i n t h e s t r o n g a c i d .A s i m i l a r study was c a r r i e d o u t on As as A s ( I I 1 ) and As(V). The i n t e r f e r e n c e was g r e a t e r f o r As(V) t h a n f o r A s ( I I 1 ) (2332).I t was t h o u g h t t h a t t h i s was due t o t h e more complete p r e c i p i t a t i o n o f t h e i n t e r f e r i n g metals by t h e t i m e t h e h y d r i d e was formed from As(V), c o n f i r m i n g t h e t h e o r y t h a t t h i s i n t e r f e r e n c e i s a g a s - s o l i d r e a c t i o n . A f u r t h e r s t u d y (2334) i n v e s t i g a t e d t h e r e l e a s i n g e f f e c t o f F e ( I I 1 ) on t h e i n t e r f e r e n c e from N i on t h e d e t e r m i n a t i o n o f As and Se.I t was proposed t h a t t h e r e l e a s i n g e f f e c t was due t o t h e p r e f e r e n t i a l r e d u c t i o n o f F e ( I I 1 ) t o F e ( I 1 ) which i n h i b i t e d t h e p r e c i p i t a t i o n of t h e i n t e r f e r i n g N i as t h e metal.Lajunen e t a l . (1791) r e p o r t e d t h e i n f l u e n c e o f h y d r i d e - f o r m i n g elements on Sb d e t e r m i n a t i o n . The i n t e r f e r e n c e was found t o i n c r e a s e i n t h e o r d e r E l i < As < Te < Ge < Se < Sn. The use o f masking agents such as CuS04 ( f o r B i and Se) and K I / a s c o r b i c a c i d ( f o r Se, Sn, and Te) removed t h e i n t e r f e r e n c e .The d e t e r m i n a t i o n o f Hg a t ng 1-1 l e v e l s i s a t t r a c t i n g c o n s i d e r a b l e a t t e n t i o n . To achieve t h i s l e v e l i t i s necessary t o use l a r g e sample volumes and c o n c e n t r a t e t h e Hg vapour, *, on a Au o r Au/Pt gauze t r a p p r i o r t o r e v o l a t i l i z a t i o n o f Hg vapour by r a p i d heating.T h i s i s more g e n e r a l l y known as t h e mercury-amalgam technique. Neske e t a l . (2591) o b t a i n e d a d e t e c t i o n l i m i t o f 330 pg o f Hg. Concentrations o f l e s s t h a n 0.5 ng 1-I were d e t e c t a b l e w i t h a sample volume o f 1 1. Welz and Melcher (791, 1238) r e p o r t e d t h a t optimum c o n d i t i o n s were a Au/Pt gauze f o r Hg c o l l e c t i o n , g l a s s - f i b r e f i l t e r i n s t e a d o f a102 Analytical Atomic Spectroscopy desiccant H20 removal, PTFE tubing, SnC12 instead o f NaBH4 as t h e reducing agent and He c a r r i e r gas instead o f A r o r N2.The s e n s i t i v i t y was 0.25 ng under optimum conditions. Concentrations below 1 ng 1-1 could be determined from a 1 1 sample volume: however, t h e l i m i t i n g f a c t o r was t h e blank l e v e l .f o r 3.1.4 Speciation It is now becoming i n c r e a s i n g l y obvious t h a t t h e form o r 'species' o f an element i n a p a r t i c u l a r sample may be o f importance. The terra species includes t h e o x i d a t i o n s t a t e f o r a p a r t i c u l a r analyte and t h e organic o r inorganic form.It i s n o t s u r p r i s i n g t h a t t h e l i t e r a t u r e on t h i s subject i s growing r a p i d l y . Olsen (C1393) reported t h e s p e c i a t i o n o f organo-As, Hg, and Se compounds by c a p i l l a r y chromatography-microwave induced plasma. The M I P i s w e l l s u i t e d as a detector f o r GC (C1106, 1387, 1388, 1809).For m e t a l l i c compounds t h a t are i n v o l a t i l e , t h e p r e f e r r e d separation method i s h i g h performance l i q u i d chromatography. Ebdon e t a l . (C1107, C2413, C2474) presented data f o r the HPLC separation o f organo-As and Sn species i n environmental samples. A review o f coupled HPLC-ICP-OES was published by Van der Voet (C1442). A d d i t i o n a l references on t h e preceding t o p i c - 461, 493, 681, C1401, C1402, 2556, C2617).Speciation can a l s o be achieved by e x t r a c t i o n methods. The e x t r a c t i o n o f Se(1V) and Te(IV) from aqueous s o l u t i o n s w i t h APDC i n t o CHC13 and CC14 was reported (819). The higher o x i d a t i o n states were n o t e x t r a c t e d over t h e e n t i r e pH range studied.The sample was pre-reduced w i t h TiC13 f o r measurement o f t o t a l Se and Te content. A r s e n i c ( I I 1 ) and As(V) were determined s i m i l a r l y (1855). An i n t e r e s t i n g method f o r t h e determination o f C r species using a g r a p h i t e furnace was reported (491). A 20 ~1 a l i q u o t o f a mixture o f t r i f l u o r o a c e t y l a c e t o n e (TFA) and urea was p i p e t t e d i n t o a g r a p h i t e furnace followed by 5 ~1 o f a C r s o l u t i o n .The urea decomposed w i t h increasing temperature and a NH3-TFA complex was formed. This o n l y reacted w i t h C r ( I I 1 ) forming a v o l a t i l e compound which was evaporated from t h e g r a p h i t e tube. The remaining Cr(V1) was subsequently atomized and determined.A d d i t i o n a l references on t h e preceding t o p i c - C391. 890, C1136. 2580. 3.1.5 I n d i r e c t Methods Many o f t h e i n d i r e c t methods o f a n a l y s i s published r e c e n t l y were based on t h e molecular absorption o f monohalides produced by v a p o r i z a t i o n i n a g r a p h i t e furnace. I n a s e r i e s o f a r t i c l e s D i t t r i c h e t a l .(285, 2338, 2339) reported t h e determination o f C1 i n s i l v e r h a l i d e samples and semiconductor materials. The AgCl was dissolved i n NH3 and, a f t e r a d d i t i o n o f A l ( I I 1 ) and Ba(OH)2, t h e molecular absorption o f t h e A l C l was measured a t 261.4 nm. It was foundMethodology 103 p o s s i b l e t o determine 0.2 ug g-' C1 i n 500 mg o f semiconductor m a t e r i a l (As, Ga, o r Se).The d i r e c t determination o f F i n m i l k by A1F absorption i n a g r a p h i t e furnace was reported (1248). The concentration o f F i n commercial m i l k was found t o be 0.033 pg ml-'. The i n d i r e c t determination o f CN i n waters was reported (286). I n some cases i t i s d i f f i c u l t t o see t h e advantages o f c e r t a i n i n d i r e c t methods o f analysis. I o n - s e l e c t i v e electrodes may p r o v i d e a more appropriate s o l u t i o n t o many a n a l y t i c a l problems o f t h i s type.Other references o f i n t e r e s t - I n d i r e c t AAS determination o f S using Ba: 910. I n d i r e c t AAS method f o r t h e determination o f organic di-, tri-, and tetra-sulphides: C383.I n d i r e c t a n a l y s i s o f f u n c t i o n a l organic compounds: 2124. I n d i r e c t determination o f organic compounds by AAS (review): 294. 3.1.6 The procedure o f atom t r a p p i n g was applied i n FAAS (C1729; see a l s o Section 1.3.3.1) t o the a n a l y s i s o f a g r i c u l t u r a l and environmental materials.The accuracy f o r t h e determination o f As, Cd, and Pb i n s o i l e x t r a c t s and aqua r e g i a d i g e s t s o f s o i l s and sewage sludges was v a l i d a t e d by t h e analysis o f appropriate CRMs. Hallam and Thompson (C2449) described an improved design o f atom t r a p and a p p l i e d i t t o t h e determination o f Cd and Pb i n potable waters. Improve- ments i n s e n s i t i v i t y f o r FAAS can also be obtained by use o f a s l o t t e d quartz tube (see a l s o Section 1.3.3.2).This procedure has been a p p l i e d t o the deter- mination o f Cu and Zn i n serum and u r i n e samples (1872). Cd and Pb i n whole blood and u r i n e (C332) and Cd and Pb i n n a t u r a l and potable waters (C2453). Developments i n idethodology f o r Atomic Absorption Spectrometry I n electrothermal atomization atomic absorption spectrometry t h e d r y i n g and ashing stages take up 80 - 100 s o f the g r a p h i t e furnace programme and hence t h e technique i s comparatively slow.Thus various workers have attempted t o reduce t h e time o f these stages. Dabeka (C1149) presented r e s u l t s which demonstrated, unexpectedly, t h a t a long d r y i n g time produced inaccurate r e s u l t s f o r some elements and a l s o reduced tube l i f e t i m e .Reduction o f t h e d r y i n g time t o 5 - 10 s e l i m i n a t e d these e f f e c t s and doubled the a n a l y t i c a l throughput. Various r o u t i n e a n a l y t i c a l methods were evaluated by H a l l s (1859) i n an e f f o r t t o increase a n a l y t i c a l throughput. For c e r t a i n analyses (s, Pb i n blood) i t was found t h a t d r y i n g a t elevated temperatures (130 "C) f o r 15 s was p o s s i b l e and t h a t i n t h i s p a r t i c u l a r method (using d e p r o t e i n i z a t i o n w i t h HNO ) t h e ashing stage could be completely eliminated.The new furnace programme, which increased a n a l y t i c a l throughput by a f a c t o r o f 2.3, was evaluated by comparing r e s u l t s obtained f o r q u a l i t y c o n t r o l (QC) samples t o r e s u l t s obtained by a conventional method, and a l s o t o t h e mean QC r e s u l t s from other p a r t i c i p a t i n g l a b o r a t o r i e s .This paper a l s o presents data f o r A1 i n potable waters and Cu i n 3104 Analytical Atomic Spectroscopy urine.I n a l l cases s u b s t a n t i a l reductions i n t h e time taken per sample a n a l y s i s was obtained. Lewis e t a l . (873) reported t h e use of a continuum source multi-element flame atomic absorption spectrometer f o r t h e simultaneous determination o f Ca, Cu, Fe, K, Mg, Na, and Zn i n blood serum. Owing t o the extended range c a p a b i l i t i e s o f t h i s instrument (see ARAAS, 1982, 11, 27).t h e complete analysis was Accuracy was assessed by a n a l y s i s o f serum CRPls. The RSDs o f day-to-day p r e c i s i o n studies ranged from 1.4% f o r Na t o 1.1% f o r Fe. performed w i t h a s i n g l e 5-times d i l u t i o n o f sample w i t h H 0. 2 3.1.7 This year has seen increased i n t e r e s t i n t h e combination o f g r a p h i t e furnace v a p o r i z a t i o n and e x c i t a t i o n i n an I C P (see a l s o Section 1.2.1.2).One approach, adopted by Van Loon e t a l . (1413, 1437, 2329), used a g r a p h i t e furnace t o vaporize s o l i d samples of a i r f i l t e r s o r s i l i c a t e rocks. The furnace was interfaced t o t h e I C P via a heated t r a n s f e r tube which was connected t o t h e base o f the plasma. For a i r f i l t e r samples, recoveries were acceptable f o r Cu, Pb, and V.Tikkanen and Niemczyk (1760) described a procedure t o modify a commercial d i r e c t - r e a d i n g I C P spectrometer t o incorporate and electrothermal atomizer. It was claimed t h a t m o d i f i c a t i o n s could be made i n such a manner t h a t allowed simple and r a p i d changeover between systems. The r e s u l t s obtained f o r t h e determination o f Ag, C r , Cu, and 14n compared favourably w i t h those reported from a s i n g l e channel system.Freeman e t a l . (C1534) described a continuous f l o w sample i n t r o d u c t i o n system i n t o a g r a p h i t e furnace p r i o r t o ICP-OES. A low f l o w r a t e of sample was pumped d i r e c t l y i n t o a g r a p h i t e furnace which was kept a t a h i g h constant temperature.Signal i n t e g r a t i o n increased t h e p r e c i s i o n over d i s c r e t e furnace atomization. Developments i n i4ethodology f o r Plasma O p t i c a l Emission Spectrometry Novel a p p l i c a t i o n s of t h e d i r e c t i n s e r t i o n technique have been reported (see a l s o Section 1.2.1.2).Page e t a l . (312) s u i t a b l y adapted a c a r r i e r d i s t i l l a t i o n technique, as used f o r s e l e c t i v e v o l a t i l i z a t i o n o f t r a c e elements from r e f r a c t o r y matrices i n d.c. arc e x c i t a t i o n , and developed an I C P method f o r t h e simultaneous determination o f B.Be, Cd, Co, C r , Cu, Fe, K, L i , Mn, Na, and Pb i n uranium oxide powders. More r e c e n t l y t h e d i r e c t determination o f Cd i n b i o l o g i c a l and metal oxide samples (2246) has been demonstrated, as w e l l as t h e simultaneous determination o f 15 elements i n p l a n t t i s s u e d i g e s t s (2249). By f a r t h e major advance i n plasma spectrometry has been t h e i n t r o d u c t i o n o f commercially a v a i l a b l e i n d u c t i v e l y coupled plasma-mass spectrometry instruments (see a l s o Section 1.2.1.4).P u b l i c a t i o n s are appearing a t a p r o l i f i c r a t e . A s e r i e s o f a r t i c l e s which may i n t e r e s t the newcomer t o t h i s technique have appeared (1952, 1953, 1954, 1955).The technique has been applied t o t h e analysis o f c l i n i c a l (C2420, C2454, C2462) and geological ((2430,Methodology 105 C2452) m a t e r i a l s . Other r e f e r e n c e s o f i n t e r e s t - Enhanced s e n s i t i v i t y i n t h e d e t e r m i n a t i o n o f Hg by ICP-OES: 968. The design and c h a r a c t e r i z a t i o n o f an i n t e r f a c e f o r HPLC-DCP: 2322. 3.2 DETECTIOIi! LIiVlITS, PRECISION AND ACCURACY A comparison o f an aqua r e g i a l e a c h method and a f i r e assay f u s i o n method f o r t h e d e t e r m i n a t i o n o f Au i n g e o l o g i c a l samples was r e p o r t e d (2). T h i s s t u d y found t h a t t h e mean p r e c i s i o n , d e f i n e d as ' t h e a b i l i t y t o o b t a i n t h e same v a l u e w i t h a 98% confidence, ' was 230% f o r t h e aqua r e g i a l e a c h and 215% f o r t h e f u s i o n .A l a r g e p r o p o r t i o n o f t h i s r e p o r t discussed sampling and sample p r e p a r a t i o n i n t h e e x p l o r a t i o n i n d u s t r y . Boyer e t a l . (C1593) s t a t i s t i c a l l y analysed d a t a o b t a i n e d o v e r a 9 year p e r i o d from 25 AOAC c o l l a b o r a t i v e s t u d i e s f o r t h e d e t e r m i n a t i o n o f t r a c e elements i n foods.The s t u d y concluded t h a t t h e development o f a l a r g e p r e c i s i o n d a t a base from a c o l l a b o r a t i v e s t u d y o f a n a l y t i c a l methods p r o v i d e d a u s e f u l means f o r comparison and e v a l u a t i o n o f performance c h a r a c t e r i s t i c s and l i m i t s o f a p p l i c a b i l i t y o f i n d i v i d u a l a n a l y t i c a l methods.A method t o improve t h e p r e c i s i o n o f p r e c i o u s metal analyses by DCP-OES from k 3 t o 20.5% was developed by Savolainen e t a l . (C60). To achieve t h i s , a l l phases o f t h e a n a l y t i c a l method were optimized.Improvements t o i n s t r u m e n t a t i o n i n c l u d e d t h e use o f a h i g h s t a b i l i t y p e r i s t a l t i c pump, development o f a plasma j e t alignment procedure and use o f a computer f o r sampling, a n a l y s i s , and d r i f t c o n t r o l . F r a l e y (C61) used t h e i n t e r n a l standard t e c h n i q u e t o c o r r e c t f o r v a r i a t i o n s i n sample w e i g h t and d i l u t i o n volume.U s i n g t h i s technique i t was found t h a t p r e c i s i o n and accuracy c o u l d be maintained w i t h o u t a c t u a l l y knowing t h e sample w e i g h t o r t h e d i l u t e d volume o f t h e f i n a l s o l u t i o n . Wojciak (C62) discussed sample p r e p a r a t i o n and s t a t i s t i c s as a p p l i e d t o ICP-OES (see a l s o S e c t i o n 1.2.1.3).P e z z u l l o (C63). d u r i n g t h e same conference session, expanded on t h e s t a t i s t i c a l i n t e r p r e t a t i o n o f r e s u l t s f o r ICP-OES a n a l y s i s . Bankston (C95) discussed procedures f o r e v a l u a t i n g t h e performance o f a n a l y t i c a l methods. One c o n c l u s i o n reached was t h a t t h e t e r m ' d e t e c t i o n l i m i t ' was n o t considered t o be a t r u e performance c h a r a c t e r i s t i c f o r a n a l y t i c a l methods.It was a l s o suggested t h a t i t a k i n g account of t h e s i g n i f i c a n t random c a l i b r a t i o n f u n c t i o n , t h e n t h e v a l u e o f r e v i e w on t h e u s e f u l n e s s o f signal-to-no was p u b l i s h e d (825).B o t t o ( 9 ) p u b l i s h e d a paper on t h e d e t e c t i o n l i m i t is d e f i n e d w i t h o u t e r r o r o f a s t a t i s t i c a l l y determined t h e d e t e c t i o n l i m i t i s f a l s e l y low. A se t r e a t m e n t i n a n a l y t i c a l c h e m i s t r y q u a l i t y assurance i n t h e o p e r a t i o n o f a106 Analytical Atomic Spectroscopy multi-element ICP.Six e s s e n t i a l components of a q u a l i t y assurance programme were described f o r t h e i n d u s t r i a l l a b o r a t o r y where the ICP was operated by technicians w i t h l i t t l e o r no t e c h n i c a l background i n spectrochemical analysis. The importance o f adequate r e s o l u t i o n and proper choice o f wavelengths f o r o f f - l i n e background measurements was stressed.A review on t h i s s u b j e c t i s recommended reading (2135). Sampling methods, v a l i d a t i o n o f a n a l y t i c a l data, and data handling and evaluation were discussed i n d e t a i l w i t h respect t o t h e use o f atomic spectrometry i n t h e food industry. 3.3 STANDARDS AND STANDARDIZATION 3.3.1 Reference Materi a1 s There has been increaed a c t i v i t y i n t h e development o f g e o l o g i c a l reference materials.A phosphate rock CRM c e r t i f i e d f o r 13 t r a c e elements has been issued by BCR and d e t a i l s of preparation, homogeneity t e s t s and c e r t i f i c a t i o n were given (1257). A s i m i l a r account f o r a l a k e sediment RM was reported (1032).and i n t e r l a b o r a t o r y studies i n v o l v i n g AAS, ICP-OES and NAA methodologies provided t h e basis f o r c e r t i f i c a t i o n o f As, Hg, and Se. The BCR has produced a f l y ash CRN and d e t a i l s o f a l l aspects o f methodology and c e r t i f i c a t i o n have been published (103). The preparation o f a sea-water CRM (NASS-1).c e r t i f i e d f o r 11 t r a c e elements, has been described (1256). Storage experiments i n d i c a t e d t h a t t h e sea-water was not contaminated (except by Pb) as a r e s u l t o f sample c o l l e c t i o n and prolonged storage. The NBS has made a v a i l a b l e a series o f 9 h i g h - p u r i t y spectrometric standard s o l u t i o n s (SRMs 2121 - 2129).The CRbls a r e intended t o provide primary standardization o f multi-element techniques such as ICP-OES. The development work on uranium oxides RMs, r e f e r r e d t o i n an e a r l i e r volume (see ARAAS, 1983, 13, Ref. 2330) has now been published (1012). Other references o f i n t e r e s t - Assessment o f methods o f assigning c e r t i f i e d values t o RI-ls: 1265.A v a i l a b l e standards f o r use i n t h e analysis o f marine materials: NRCC No. 23025. B i o l o g i c a l RNs - a v a i l a b i l i t y , uses and needs f o r n u t r i e n t analysis: ed. W.R. Wolf, Wiley-Interscience, New York. Compilation o f elemental data f o r NBS b i o l o g i c a l , geochemical and environmental CRNs: NBS Special P u b l i c a t i o n 260-85.Determination of t r a c e elements i n bovine serum research materials: C1174. Reference m a t e r i a l s f o r t r a c e analysis: 1072.Methodology 107 3.3.2 Standardization Studies I n t e r l a b o r a t o r y studies have been reported i n a number o f f i e l d s . Smith (297) has reviewed t h e progress and organization o f i n t e r l a b o r a t o r y studies, f i r s t c a r r i e d o u t i n 1976, by water analysis l a b o r a t o r i e s i n South A f r i c a .The need f o r an updated s e t of standard methods was h i g h l i g h t e d and r e s u l t e d i n t h e p u b l i c a t i o n o f recommended methodology f o r t h e determination o f 19 by AAS (2369). An i n t e r l a b o r a t o r y a n a l y t i c a l q u a l i t y c o n t r o l programme has been devised by water a u t h o r i t i e s i n t h e UK and r e s u l t s by AAS f o r Cd, C r , Cu, Fe, Hg, Mn, i d i , Pb, and Zn i n sewage, t r a d e e f f l u e n t s and r i v e r water have been published ( A n a l y s t , 1984, 109, 3).Overall, t h e r e s u l t s f o r t h e exercise were considered very s a t i s f a c t o r y although c o r r e c t i o n f o r non-specific background absorption was found t o be e s s e n t i a l f o r Cd, N i , Pb and Zn.A comparative study o f ETA-AAS f o r t h e determination o f Pb i n i n f a n t formulas and evaporated m i l k y i e l d e d values i n t h e range 29 - 200 ng g-l (1869). The f a i l u r e t o reach agreement was a t t r i b u t e d t o t h e inadequacy o f t h e background c o r r e c t i o n f a c i l i t i e s on t h e instruments used.The i m p l i c a t i o n s o f t h i s f i n d i n g extend t o o t h e r elements and matrices and i t was proposed t h a t a s u i t a b l e RM be developed f o r t h e purpose o f v e r i f y i n g t h e adequacy o f background c o r r e c t i o n systems. Comparative r e s u l t s f o r Cd, Cu, Fe, Pb, Sn and Zn i n samples o f spiked and unspiked apple puree have been reported by l a b o r a t o r i e s i n A u s t r a l i a (806).Flame AAS was considered t o p r o v i d e accurate data f o r Cu, Fe and Zn. Minderhoud (1262) has discussed t h e r o l e o f i n t e r l a b o r a t o r y studies, s t a n d a r d i z a t i o n o f methods, and CRMs i n t h e context o f s e t t i n g p o l l u t i o n c o n t r o l standards.S p e c i f i c samples considered were hazardous wastes, sewage sludge, waters, sediments and a i r p a r t i c u l a t e s . Other references o f i n t e r e s t - elements Comparison o f 5 methods f o r t h e determination o f t r a c e metals i n sea water: 1750. Determination o f Hg i n geological RMs: 729. Determination o f Se i n b i o l o g i c a l m a t e r i a l and water: 895.Intercomparison o f AAS and ASV f o r t h e determination o f t r a c e metals sea water: 2022. Q u a l i t y c o n t r o l sera f o r r o u t i n e determination o f A l : 426. Sources o f e r r o r i n t r a c e element analysis o f surface waters: 1765. i n108 Analytical Atomic Spectroscopy TABLES 3.3A. 1 - 3.3A.8: CERTIFIED REFERENCE MATERIALS Explanation: i n f o r m a t i o n g i v e n i n t h e Tables r e p r e s e n t s t h e c u r r e n t a v a i l - a b i l i t y o f RMs c e r t i f i e d f o r elemental composition. U n c e r t i f i e d RMs a r e n o t i n c l u d e d i n t h e l i s t i n g s .Categories o f Rbls a r e based on those proposed by t h e I n t e r n a t i o n a l O r g a n i s a t i o n f o r S t a n d a r d i z a t i o n ( I S O ) .The TABLE 3.3A. 1 CHEMICALS AND INDUSTRIAL PRODUCTS S u p p l i e r M a t e r i a1 Sureau N a t i o n a l de I j e t r o l o g i e s (BNM, 8-10 r u e C r i l l o n , 75194 P a r i s Cedex 04, France Fuel o i l Commission o f t h e European Communities, Community Bureau of Reference (BCR), 200 r u e de l a L o i , B-1049 Brussels, Be1 g i um Carbone L o r r a i n e , 45 r u e des Acacias, BP 164, 75017 P a r i s , France Commissariat a 1 ' E n e r g i e Atomique, C r i s t a l Tec, BP 85 Centre de tri, 38041 Grenoble Cedex, France I n d u s t r i a l M a n u f a c t u r i n g I n s p e c t i o n 6-15-1 Ginza, Chuoku, Tokyo, Japan N a t i o n a l Bureau o f Standards, O f f i c e o f Standard Reference M a t e r i a l s , Washington, DC 20234, U.S.A.I n s t i t u t e , N a t i o n a l P h y s i c a l Laboratory, O f f i c e o f Reference M a t e r i a l s , Teddington, Middlesex, TW11 OLW, England Organometallic compounds, phosphate f e r t i l i z e r Reagents Reagents P r i m a r y standards P r i m a r y standards, f e r t i l i z e r s , f u e l and l u b r i c a t i n g o i l s , o r g a n o m e t a l l i c compounds, s p e c t r o m e t r i c s t o c k standard s o l u t i o n s Fuel o i l , o r g a n o m e t a l l i c compoundsMethodology 109 TABLE 3.3A. 1 CHEIIICALS AND INDUSTRIAL PRODUCTS (continued) Supp 1 i e r Materi a1 P r o d u i t s Chimiques Ugine Kuhlmann, Reagents l e Rubis Synthetique des Alpes, 38560 J a r r i e , France Prolabo, 12 rue Pelee, BP 200, 75526 P a r i s Cedex 11, France RhGne-Poulenc Chimie Fine 21 rue Jean Goujon, 75008 Paris, France Reagents Reagents Service des Materiaux de Reference Fuel o i l 1 rue Gaston Boissier, 75015 Paris, France (SMR 1.TABLE 3.3A.2 FERROUS LIETALS AND ALLOYS Suppl i e r F i n e l y d i v i d e d form S o l i d form A m t fir Standardisierung und WarenprGfung (ASMW), 102 B e r l i n , Wallstrasse 16, D.D.R.Bundesanstalt f i r M a t e r i a l - 1 B e r l i n 45, Unter den Eichen 87, Germany p r i f ung (BAP.1) , Bureau o f Analysed Samples Ltd., Newham H a l l , Newby, P l i d d l esbrough Cleveland, TS8 9EA, England Bureau National de r l e t r o l o g i e 8-10 rue C r i l l o n , 75194 P a r i s Cedex 04, France ( BNFl), Unal loyed and a1 loyed steels, c a s t i r o n s , slags, f e r r o a l l o y s Unalloyed and a l l o y e d steels, slags, c a s t i r o n s , f e r r o a l l o y s High p u r i t y i r o n s , Unalloyed and unalloyed and a l l o y e d a l l o y e d steels, steels, slags, c a s t i r o n s , f e r r o a l l o y s c a s t i r o n s High p u r i t y i r o n s110 Analytical Atomic Spectroscopy TABLE 3.3A.2 FERROUS CIETALS AND ALLOYS (continued) ~~ Supplier F i n e l y d i v i d e d form S o l i d form Centre Technique des I n d u s t r i e s 44 Avenue de l a D i v i s i o n Leclerc, 92310 Sevre, France de l a Fonderie (CTIF), Centro Nacional de Investigaciones Cu i d ad Uni vers i t a r i a, Madrid 3, Spain Metalurgicas, Gosstandard o f t h e USSR, 9 Leninsky Prospekt, 11 704 Moskow, U.S. S. R. I n s t i t u t de Recherches de l a BP 129. 78100 S a i n t Germaine en Laye, France S i d i r u r g i e Francai se, I n s t i t u t o de Pesquisas Sao Paulo S/A-IPT, D i v i s a o de Quimica e Engenharia Nucleo de Padroes Analyticos, Caixa Postal 7141, 01000-Sao Paulo - SP, Brazi 1 Tecnologicas do Estato de Qu i m i ca, I r o n and Steel I n s t i t u t e o f 9-4, 1-Chome, Otemachi, Chi yoda- ku, Tokyo, Japan Japan, MBH A n a l y t i c a l Limited, H o l l and House, Queens Road, Barnet, Herts.EN5 4DJ, England Metalimpex, POB 330, Hungary H-1376, National Bureau o f Standards, O f f i c e o f Standard Reference Washington. DC 20234, U.S.A. Materials, C s t e e l s C s t e e l s Unalloyed and a1 loyed s t e e l s Unalloyed and a1 loyed steels, c a s t i r o n s Unalloyed and a l l o y e d Unalloyed and s t e e l , f e r r o a1 loys, a1 loyed s t e e l s c a s t i r o n s , slags Unal 1 oyed and a1 1 oyed s t e e l s Unalloyed and a1 loyed steels, c a s t i r o n s a l l o y e d s t e e l s Unalloyed and Unall oyed and a l l o y e d steels, c a s t i r o n s Unal 1 oyed and a1 loyed s t e e l s a l l o y e d steels, Unal 1 oyed and c a s t i r o n s Unalloyed and a l l o y e d Unalloyed and steels, c a s t i r o n a l l o y e d steels, c a s t i r o n sMethodology 1 1 1 TABLE 3.3A.2 FERROUS NETALS AND ALLOYS (continued) Supplier F i n e l y d i v i d e d form S o l i d form Pro1 abo 12 rue PelGe, BP 200, 75526 P a r i s Cedex 1 1 , France Spex I n d u s t r i e s Inc., 3880 Park Avenue, Metuchen, NJ 08840.U.S.A. Steels Unalloyed and a1 1 oyed s t e e l s, c a s t i r o n s Swedish I n s t i t u t e f o r Metal Unalloyed and a1 loyed Research, steels, f e r r o a1 loys, D r o t t n i n g K r i s t i n a s vag 48, S-11428 Stockholm, Sweden s l ags South A f r i c a n Bureau of Ferro a l l o y s P r i v a t e Bag XI91 , Pretoria, Transvaal 0001.South A f r i c a Standards, TABLE 3.3A.3 NON-FERROUS METALS AND ALLOYS Supplier F i n e l y d i v i d e d form S o l i d form A i r Products Ltd., Cu, Mo, Pb, T i . Special Prods Dept. , Z r base Weston Road, Crewe, Cheshire, CW1 lDF, England Aluminium Company o f America, Alcon Technical Center, A1 con Center, PA 15069, U.S.A. A1 umi n i um Pec h i ney , 23 b i s , r u e Balzac, 75360 P a r i s Cedex 08, France A m t f b r Standardisierung und Sn, A l , Mg base Warenprifung (ASNW), 102 B e r l i n , Wal l s t r a s s e 16, D.D. R. A1 base High-purity metals A l , Flg base A l , Cu112 Analytical Atomic Spectroscopy TABLE 3.3A.3 NON-FERROUS NETALS AND ALLOYS (continued) ~ Suppl i e r F i n e l y d i v i d e d form S o l i d form B r i t i s h Aluminiuin Co.Ltd., C h a l f o n t Park, Gerrards Cross, Sucks. SL9 OQB, England Bundesanstalt fir M a t e r i a l - Cu, Ni, A l , Mg base 1 B e r l i n 45, U n t e r den Eichen 87, Germany Bureau o f Analysed Samples Ltd., Newham Hal 1. Newby, Al, Mg, Cu. N i , Sn, M i dd 1 esbrough Cleveland, TS8 9EA, England BNF M e t a l s Technology Centre Grove L a b o r a t o r i e s , Denchworth Road, Wan tage, Oxfordshire, England Canada Centre f o r M i n e r a l c / o Coordinator.CANHET, 555 Booth S t r e e t , Ottawa, O n t a r i o K I A OG1, Canada prGfung (BAN), High-puri t y metals Pb base Energy Technology, Comni s s a r i a t a 1 ' E n e r g i e Atomique (CEA), C r i s t a l Tec, BP 85 Centre de tri, 38041 Grenoble Cedex, France Centre Technique des I n d u s t r i e s 44 Avenue de l a D i v i s i o n L e c l e r c , 9231 0 S'evres, France de l a Fonderie (CTIF), Centre Techniques du Zinc, 34 r u e Collange, 92300 Leva1 l o i s P e r r e t , France Chemicals I n s p e c t i o n & T e s t i n g 1-1, 4-Chome, Higashi-Mukojima, Sumida-Ku, Tokyo.Japan I n s t i t u t e , A1 base High P u r i t y m e t a l s A l , Cu, N i base A l , Cu, N i base Cu base A l , Mg base Cu base H i g h - p u r i t y metals, Zn base A l , Cu, N i baseMethodology 113 TABLE 3.3k.3 NON-FERROUS METALS AND ALLOYS (continued) Supp 1 i e r F i n e l y d i v i d e d form S o l i d form Commission o f t h e European Community Bureau o f Reference 200 r u e de l a L o i , B-1049 Brussels, Be 1 g i urn Cornmun i t i es , (BCR), Gosstandard of t h e USSR, 9 Leninsky Prospekt, 11 704 I~OSCOW, U.S. 8. R. I n c o Europe Ltd, European Research & Development Commerci a1 Development Department, Birmingham 816 OAJ, England Centre , I n s t i t u t o de Pesquisas Tecnologicas do Estado de Sao Paulo S/A-IPT, Quimica, D i v i s a o de Quimica de Engenharia Nucleo de Padroes A n a l y t i c o s , Caixa P o s t a l 7141, 01100-Sao Paulo-SP, B r a z i 1 A l l Cu, N i base Japan Aluminium Federation, A l l Cu, Mg base Nihonbashi Mei j i B u i l d i n g , 1-3, 2-Chorne1 N i honbashi, Japan Japan Brass Makers A s s o c i a t i o n , 12-22, 1-Chome, T s u k i j i , Japan Chuo-Ku, Tokyo, Chuo-Ku, Tokyo, Japan L i g h t PSetal A s s o c i a t i o n , 1-3, 2-Chome, N i honbashi, Japan Chuo-Ku, Tokyo.Johnson Matthey Chemicals Ltd., H i g h - p u r i t y metals Orchard Road, Royston, H e r t s SG8 5HE, England MBH A n a l y t i c a l L t d ., Hol1 and House, Queens Road, Barnet, H e r t s EN5 4DJ, England A l , Cu, N i base A l l Cu, N i base Cu base A l l Cu, Mg base A l l Cu, Mg base H i gh-puri t y m e t a l s A l , Cu, N i l Zn, Co base114 Analytical Atomic Spectroscopy TABLE 3.3A. 3 NON-FERROUS METALS AND ALLOYS (continued) Supplier F i n e l y d i v i d e d form S o l i d form blercure I n d u s t r i e , 13 rue Saulnier, 92800 Puteaux, France High-purity metals Metal impex, POB 330, H-1376 Budapest, Hungary National Bureau o f Standards, High-purity metals, O f f i c e of Standard Reference A l , Co, Cu, N i , Pb, Materi a1 s Mg, Sn. T i , Zn, Z r Washington , DC 20234, base U.S.A. P1 anet-Wattohm, 05310 l a Roche de Rame, France Pro1 abo, 12 r u e Pelge, BP 200, 75526 P a r i s Cedex 11, France Rhhne-A1 pes Mercure, 4 Rue des Fauvettes, Mons V i l e t t e D'Authon, 33230 Pont de Cheruy, France Spex I n d u s t r i e s Inc., 3880 Park Avenue, Metuchen, NJ 08840, U. S.A. High-purity metals High-purity metals A1 base A l , Cu, Pb, N i , T i , Zn, Z r base High-purity metals Cu, Pb, Sn base TASLE 3.3A.4 GEOLOGICAL MATERIALS Supplier F i n e l y d i v i d e d form A m t f i r Standardisierung und Warenprufung (ASMW), 102 B e r l i n , Wallstrasse 16, D.D.R.Mn, Cr, Sn ores Bundesanstal t fir Materi a1 pr;fung 1 B e r l i n 45, Unter den Eichen 87, Germany Fe ores ( BAbI ) ,Methodology TABLE 3.3A.4 GEOLOGICAL MATERIALS ( c o n t i n u e d ) 115 S u p p l i e r F i n e l y d i v i d e d form Bureau o f Analysed Samples Ltd., Newham Hal 1.Newby, Middlesbrough, Cleveland TS8 9EA, England Canada Centre f o r M i n e r a l and Energy c / o Coordinator, CANMET, 555 Booth S t r e e t , Ottawa, O n t a r i o K1A OG1, Canada Technology, Centre N a t i o n a l de l a Recherche S c i e n t i f ique, Centre de Recherche Petrographiques e t Geochimiques (CNRS/CRPG), 15 r u e Motre Dame des Pauvres, Case O f f i c i e l l e No. 1, 54500 Vandocuvre-lez-Nancy, France Commission o f European Communities, Community Bureau o f Reference (BCR), 200 r u e de l a L o i , B-1049 Brussels, Belgium G e o l o g i c a l Survey o f Japan, 1-3, Higashi I-Chome, Yatebemachi, Tsu ku ba-Gun, I b a r a g i , Japan Gosstandard o f t h e USSR, 9 Leninsky Prospekt, 11 704 Moscow.U. S. S. R. I n s t i t u t o de Pesquisas Tecnologicas do Estado de Sao Paulo S/A-IPT, D i v i s a o de Quimica de Engenharia Quimi ca, 01000 Sao Paulo-SP, B r a z i 1 I n t e r n a t i o n a l Atomic Energy Agency, A n a l y t i c a l Q u a l i t y C o n t r o l Services, L a b o r a t o r y Seibersdorf, PO Box 590, A-1011 Vienna, A u s t r i a Junta de Energia Nuclear, Cuidad U n i v e r s i t a r i a , Madrid-3, Spain L.R.M. , BP 3013, 54000 Nancy Cedex, France Fe, Mn, C r , A1 ores, f l u o r s p a r , s i l l i m a n i t e , [\la and K f e l d s p a r , magnesi t e , dolomite, 1 imestone Sb, Co-l40, Au, Fe, Mo ores, s y e n i t e , gabbro, u l t r a m a f i c rocks Bauxite, g r a n i t e , i r o n o r e s Zn, Sn, Cu, Mn, Pb ores, coke, s o i l s Feldspar, c l a y s , g r a n o d i o r i t e , b a s a l t U ores, l a k e sediment and s o i l Phosphate r o c k s and c l a y s U ores L i g n i t e Rocks116 Analytical Atomic Spectroscopy TABLE 3.3A.4 GEOLOGICAL MATERIALS (continued) Suppl i e r F i n e l y d i v i d e d form Marine A n a l y t i c a l Chemistry Standards Marine sediments Cheni i s t r y D i v i s i on, N a t i o n a l Research Council, ivlontreal Road, Ottawa, O n t a r i o K1A OR2, Canada Program, N a t i o n a l Bureau o f Standards, Fe, A l , Cu, Mo, L i , Zn, W ores, O f f i c e o f Standard Reference M a t e r i a l s , f l u o r s p a r , Na and K f e l d s p a r , c l a y s Washington, DC 20234, U.S.A.N a t i o n a l Chemical L a b o r a t o r y f o r R i v e r and e s t u a r i n e sediments, c o a l , 1 H i g a s h i 1-Chome, Yatebamachi, Tsukuba-Gun, I b a r a g i , Japan N a t i o n a l I n s t i t u t e f o r Environmental Pond sediment D i v i s i o n o f Chemistry & Physics, Yatabemachi, Tsukuba, I b a r a k i , Japan South A f r i c a n Bureau o f Standards, Rocks, Fe, C r , P t , and Z r ores P r i v a t e Bag X191, P r e t o r i a , Transvaal 0001, South A f r i c a I n d u s t r y , f e l d s p a r , c l a y s , g r a n o d i o r i t e .b a s a l t Studies, US G e o l o g i c a l Survey, N a t i o n a l Center 972, Reston, VA 22092, U.S.A. D i v e r s e TABLE 3.3A. 5 GLASSES, CERAMICS AND REFRACTORIES S u p p l i e r F i n e l y d i v i d e d form Bureau o f Analysed Samples Ltd., S i l i c a b r i c k , f i r e b r i c k , magnesite- Newham Hal 1, Idewby, chrome, P o r t l a n d cement, z i r c o n , h i g h - M i d d l es brough, Cleveland TS8 9EA, England Centre d'Etudes e t de Recherches de Cement 23 r u e de Cronstadt, 75015 P a r i s , France p u r i t y s i 1 i c a 1 ' I n d u s t r i e des L i a n t s Hydrauliques,Methodology 117 TAGLE 3.3A. 5 GLASSES, CERAMICS AND REFRACTORIES ( c o n t i n u e d ) Suppl i e r F i n e l y d i v i d e d form Centre N a t i o n a l de l a Recherche S c i e n t i f i que, Centre de Recherche Petrographiques e t Geoch i m i ques (CNRS/CRPG ) , 15 r u e N o t r e Dame des Pauvres, Case O f f i c i e l l e No. 1, 54 500 Van d o e u v r e - 1 e z- Na nc y , France Glasses ( 2 a v a i l a b l e ) Commission o f t h e European Communities, Community Bureau o f Reference (BCR), 200 r u e de l a L o i , 8-1049 Brussels, Be1 g i um F e d e r a t i o n Europeenne des F a b r i c a n t s de Produi t s R e f r a c t a i r e s (PRE), 44 r u e Copernic, 75016 P a r i s , France Glasses R e f r a c t o r y m a t e r i a l s L.R.M., BP 3013, 54000 Nancy Cedex. France R e f r a c t o r y m a t e r i a l s N a t i o n a l Bureau o f Standards, Lead/barium, o p a l , h i g h and low boron, O f f i c e o f Standard Reference M a t e r i a l s , soda l i m e glasses, s i l i c a , alumino- Washington, DC 20234, U.S.A. P o r t l a n d cements N a t i o n a l Chemical L a b o r a t o r y f o r Sodalime s i l i c a , s i l i c a , h i g h s i l i c i c 1 H i g a s h i l-Chome, Yatabemachi, a c i d - h i g h b o r i c a c i d g l a s s Tsukuba-Gun, I b a r a g i , Japan s i l i c a t e and chrome r e f r a c t o r i e s , Pro1 abo, 12 r u e Pelge, EP 200, 75526 P a r i s Cedex 11, France R e f r a c t o r y m a t e r i a l s S h e f f i e l d U n i v e r s i t y , G1 asses Dept.o f Ceramics, Glasses & Polymers, Northumberl and Road, S h e f f i e l d S10 2TZ, England S o c i e t y o f Glass Technology, 20 Hallam Gate Road, S h e f f i e l d S10 5BT, England Glasses ( 3 a v a i l a b l e )118 Analytical Atomic Spectroscopy TABLE 3.3A.6 BIOLOGICAL, BOTANICAL AND FOOD MATERIALS S u p p l i e r M a t e r i a l Commission o f t h e European Communities, Community Bureau o f Reference (BCR), 200 r u e de l a L o i , B-1049 Brussel s, Be1 g i um L a b o r a t o i r e N a t i o n a l d ' Essais (LNE), 1 r u e Gaston B o i s s i e r , 75015 P a r i s , France N a t i o n a l Bureau o f Standards, O f f i c e o f Standard Reference M a t e r i a l s , Washington, DC 20234, U.S.A. Marine A n a l y t i c a l Chemistry Standards A t l a n t i c Research Laboratory, N a t i o n a l Research Council, H a l i f a x , N.S., B3H 321, Canada Program, N a t i o n a l I n s t i t u t e f o r Environmental D i v i s i o n o f Chemistry & Physics, Yatabemachi, Tsukuba, I b a r a k i , Japan Studies, O l i v e leaves, p l a n t s P l a n t s Bovine l i v e r , brewers yeast, c i t r u s leaves, m i 1 k powder, o r c h a r d leaves, o y s t e r t i s s u e , p i n e needles, r i c e f l o u r , tomato leaves, wheat f l o u r Lobster Pepperbush, c h l o r e l l a , mussel TABLE 3.3A. 7 CLINICAL MATERIALS S u p p l i e r Mate r i a 1 B i omeri eux, Various l i q u i d p r e p a r a t i o n s Chemin de l'Orme, Marcy 1 ' E t o i 1 e, 69260 Charbonnieres l e s Bains, France N a t i o n a l Bureau o f Standards, Freeze-dried u r i n e and serum O f f i c e o f Standard Reference M a t e r i a l s , Washington, DC 20234, U.S.A.Methodology TABLE 3.3A.8 ENVIRONMENTAL MATERIALS 119 S u p p l i e r F i n e l y d i v i d e d form Bureau o f Analysed Samples Ltd., Newham H a l l , Newby, M i d d 1 es b r o u g h , Cleveland TSS 9EA, England Commission o f t h e European Communities, Community Bureau o f Reference (BCR), 200 r u e de l a L o i , B-1049 Brussels, Belgium Furnace d u s t (LD) Sewage sludge I n s t i t u t de Recherches de l a BP 129, 78104 S a i n t Germain en Laye, France S i d g r u r g i e Francaise, Furnace d u s t ( e l e c t r i c ) Marine A n a l y t i c a l Chemistry Standards Seawater A t l a n t i c Research Laboratory, N a t i o n a l Research Council, H a l i f a x , N.S., B3H 321, Canada Program, N a t i o n a l Bureau o f Standards, Urban p a r t i c u l a t e , coal f l y ash, O f f i c e o f Standard Reference I l a t e r i a l s , f i l t e r media, waters Washington, DC 20234, U.S.A.120 Analytical Atomic Spectroscopy TABLES 3.38.1 - 3.3B.8: REFERENCE I'IETHODS OF ANALYSIS Explanation: The i n f o r m a t i o n g i v e n i n t h e Tables i s a c o m p i l a t i o n o f r e f e r e n c e methods o f a n a l y s i s which have been p u b l i s h e d and approved by v a r i o u s o r g a n i z a t i o n s .I n t h e p r e s e n t c o n t e x t no d i s t i n c t i o n i s made between t h e terms r e f e r e n c e method, standard method, recommended method and o f f i c i a l method as used i n t h e l i t e r a t u r e .Most o f t h e methods a r e based on atomic a b s o r p t i o n spectrometry b u t flame atomic emission spectrometry, emission spectrogrphy and i n d u c t i v e l y - c o u p l e d plasma o p t i c a l emission spectrometry a l s o f e a t u r e i n t h e l i s t i n g s . Each e n t r y i n t h e Table, f o r t h e a p p r o p r i a t e body, r e p r e s e n t s e i t h e r t h e page number i n t h e standard t e x t o r t h e code number o f t h e r e f e r e n c e method.The s u p e r s c r i p t f o r each e n t r y s i g n i f i e s t h e a n a l y t i c a l technique as f o l l o w s : ( 1 ) Flame atomic a b s o r p t i o n spectrometry ( 2 ) E l e c t r o t h e r m a l a t o m i z a t i o n - atomic a b s o r p t i o n spectrometry ( 3 ) Cold vapour - atomic a b s o r p t i o n spectrometry ( 4 ) H y d r i d e g e n e r a t i o n - atomic a b s o r p t i o n s p e c t r o n e t e r y ( 5 ) Flame atomic emission spectrometry ( 6 ) I n d u c t i v e l y - c o u p l e d plasma - o p t i c a l emission spectrometry ( 7 ) Emission spectrography The names and addresses o f t h e o f f i c i a l bodies a r e g i v e n below.Reference Clethods o f A n a l y s i s - O f f i c i a l Bodies 1. 2. 3. 4. 5. 6. AMC : AOAC : APHA: ASTM: BS: DOE : A n a l y t i c a l Methods Committee Anal y t i ca 1 D i v i s i on, The Royal S o c i e t y of Chemistry, B u r l i n g t o n House, London W1V OBN, U. K. A s s o c i a t i o n o f O f f i c i a l A n a l y t i c a l Chemists, O f f i c a l Method o f A n a l y s i s ( 1 3 t h Ed.), 1111 N. 1 9 t h S t r e e t - S u i t e 210, A r l i ngton , VA 22209, U. S.A. American P u b l i c H e a l t h Association, Standards Methods f o r t h e Examination o f Water and 1015 1 5 t h S t r e e t NI, Washington, DC 20005, U. S.A. Wastewater ( 1 4 t h Ed., 1975). American S o c i e t y f o r T e s t i n g and M a t e r i a l s , 1916 Race S t r e e t , P h i l a d e l p h i a , PA 19103, u.S.A. B r i t i s h Standards I n s t i t u t i o n , 2 Park S t r e e t , London W1A 2BS, U. K. Dept. o f t h e Environment, Standing Committee of Analysts, Room A416, Romney House, 43 I4arsham S t r e e t , London SWlP 3PY, U. K.Methodology 7. 8. 9. 10. 1 1 . 12. 13. 14. EPA: HSE: I P : ISO: IUPAC: NBS: SABS: USGS: 121 US Environmental P r o t e c t i o n Agency, Methods f o r Chemical Analysis o f Water and Wastes, Office o f Research and Development, Environmental M o n i t o r i n g Systems Laboratory, Research T r i a n g l e Park, NC 27711, U.S. A. Health and Safety Executive, Room 414, S t . Hugh House, Stanley Precinct, Bootle, Merseys i de L20 3QY. U. K. I n s t i t u t e o f Petroleum, 61 New Cavendish Street, London W1M 8AR, U.K. I n t e r n a t i o n a l Organization f o r Standardization, Casa Postal 56, 1211 Geneva 20, Switzerland I n t e r n a t i o n a l Union o f Pure and Applied Chemistry, Bank Court Chambers, 2-3 Pound Way, Cowley Centre, Oxford OX4 3YF, U. K. National Bureau o f Standards, O f f i c e o f Standard Reference Materials, Washington, DC 20234, U.S.A.South A f r i c a n Bureau o f Standards, P r i v a t e Bag X191. P r e t o r i a 0001, South A f r i c a US Geological Survey, Methods f o r Determination o f Inorganic Substances i n Book 5, Chapter A l , 12201 Sunrise V a l l e y Drive, Reston, VA 22092, U.S.A. Water and F l u v i a l Sediments,c N TABLE 3.38.1 CHEMICALS AND INDUSTRIAL PRODUCTS M a t r i x Analyte AOAC ASTM BS I P I so IUPAC SABS Amrnon i um bicarbonate Baking powders Borates B o r i c a c i d Calcium c h l o r i d e Caustic soda C r y o l i t e Drugs F e r t i l i z e r s Fuel s , coal coal/coke ash ashes gas t u r b i n e gasol i ne gas ( n a t u r a l ) uranium oxide Greases, l u b r i c a t i n g O i l , e l e c t r i c a l i n s u l a t i n g f u e l ( r e s i d u a l ) f u e l and crude l u b r i c a t i n g (unused) waterborne Organic chemicals Pb DP7110(1) A1 8.023' Ca, Mg DP6918" Ca, Mg 20.043'l) Mg, K, Na E449" A l , F, Fe, Na, S i E506(3) 5050(l) Na DP2366" P DIS6374" Ca, K, Na 36.0S5" Ca, Cu, Fe, Mg, Mn, Zn Hg D3684(3) Major/minor elements D3682 ( ) Trace elements D3683'l) Inorganic c o n s t i t u e n t s Trace metals D2788") Trace metals D3605' Mn D3831" Pb D3237(1) H S D2725") E402(7) u:08 L i , Na D3340(5) cu 03635" Na D131 8 ( 5 ) Na, N i , V 288/74(' Ba, Ca, Mg, Zn Ba, Ca, Mg, Zn N i , V D3327" Hg (proposed '81 ) ( 3 ) Hg ~ 5 3 8 ( ~ ) 2.109") 308/74(' ) 1 87/66 ( 122.1 /75(7)TABLE 3.3B.1 CHEMICALS AND INDUSTRIAL PRODUCTS (continued) B M a t r i x Analyte AOAC ASTM BS I P I so IUPAC SABS P a i n t Paper boards, p u l p Sb (low conc.) C r (low conc.) Pb, Cd, Co (low conc.) Hg (low conc.) Pb Cd Ca cu Fe Mn D3717'l) D3718" D3335' D3624' ) 5.001 DIS3856/I( DIS3856/V(1 DIS3856!!! DIS3856/1' ' ) DIS777'l) DIS778!!! DIS779' ' ) DIS1830(1) Paper, h i g h l y opaque Phosphates (condensed) Phosphoric a c i d P i gmen t s Rubber pigments Pol yo1 s Sodium hydroxide Sodium phosphate Sodium sulphate Timber preservatives Urea Cd, Zn Ca Ca Cd, Zn Na, K Pb cu Mn Pb, Zn Hg Hi2 As, Cr, Cu Copper naphthenate Sn B i u r e t D1224" 425817" D1224" D2849(5) D4004' ) 607511 1 ( 3 ) DIS5373" DIS3707" DIS6678" DP6101/2(1) DP6 1 01 /3( DP6101 D I S4274' e N w124 Andy tical Atomic Spectroscopy TABLE 3.3B.2 FERROUS METALS AND ALLOYS M a t r i x A n a l y t e ASTM BS I so Cast i r o n Pb, Mg E351 K2/20: 64")" F e r r o n i c k e l co DP7520(1) I r o n o r e A1 E507" ) DIS4688" Ca, Mg E508") DIS4692(1) cu DP4693' Na, K DP6831" I r o n / C r / N i a l l o y Pb E353" B i , Pb E39'l) S t e e l N i DP4940" cu DP4943(1) S i l i c o n s t e e l s( i n g o t / carbon/low-alloy s t e e l / wrought i r o n Pb E350'l) a l l o y s t e e l Pb E352(' Tool s t e e 1 /med i um-h i gh ~ :kAustralian Standard TABLE 3.3B.3 NON-FERROUS METALS AND ALLOYS M a t r i x A n a l y t e ASTM BS I so A1 umi na Aluminium o r e s A l l u m i n i u m & aluminium a1 loys Aluminium o x i d e Cadmi urn Copper & copper a l l o y s Magnesium & magnesium a l l o y s M n Zn Cd Hg Pb 41 40/22(2) DIS3390(1 ) DIS2071" DIS5961") D I S606 1 ( 3 ) D I S5666/1-3( Cd E34'l) C r DIS3982(1) cu 1728/19(' ) DIS3980") Mg 1728/23(') DIS3256(1) Na 1728/24(l) DIS3981(1) Pb 1728/20(' Zn 1728/21(' Ca, Na, V, Zn A1 DIS5957") B i DP5959(1) Cd DIS5960(1) C r DIS4744" Cu, Te DP7602(1) Fe DP7603" N i DP7604" ) Pb, Zn E478'l) Pb DIS4749'l) Sb DP7601' Te DP7605' Zn DP4740" ) Pb 3907/15(') 41 40/AD2( ) Ag, C U T Pb, Zn E396'l)Methodology 125 TABLE 3.3B. 3 NON-FERROUS METALS AND ALLOYS ( c o n t i n u e d ) Mat r i x A n a l y t e ASTM BS I so Magnesium/chromium o r e s A1 ,Cu,Pb, Zn D IS5889 ( N i c k e l & n i c k e l a l l o y s Ag,Bi,Cd,Co, Cu, Fe,Mn, Pb, Zn DP6351' A l l S i DP7530/7(' co DP7530/2(l) C r DP7530/3(1) cu DP7530/4(1) Fe DP7530/5( M n DP7530/6( Mg 3727/21 ) Trace m e t a l s 3727/20(7) Zn 3727/22(1) N i c k e l ( e l e c t r o n i c grade) P i g l e a d Powder m e t a l s Z i n c & z i n c a l l o y s Ag, B i , Cu, Ca.K,Mg, Na DIS7627/2(' Co,Fe,Mn,Ni DIS7527/3(l Mo, T i , V D I S7627/4(l' Co, Fe,Mn,Mo, N i , Ti,V DIS7627/5(l C r DIS7627/6(1) A l , Cd, Cu, Pb, Mg E536( A1 DP4812") Cd DP4810' cu DP4811' Mg 3630/5(' ) Sn DP7155(' M e t a l s 1225(7) Zn E37(' TABLE 3.3B.4 GEOLOGICAL MATERIALS M a t r i x A n a l y t e ASTM USGS Gypsum & gypsum p r o d u c t s Na Sediment A1 As Ba Be Ca Cd co C r cu Fe Hg K Mg Mn Ag c471 ( 5 )126 Analytical Atomic Spectroscopy TABLE 3.3B.4 GEOLOGICAL MATERIALS (continued) M a t r i x A n a l y t e ASTM USGS M 0 Na N i Pb Sb Se Sn S r Zn TABLE 3.3B. 5 GLASSES, CERAMICS AND REFRACTORIES M a t r i x A n a l y t e ASTM I so SABS Cernen t Na, K Cement, blended h y d r a u l i c Na, K Glazed ceramic s u r f a c e s Pb,Cd Glazed ceramic t i l e s u r f a c e s Pb, Cd P o r c e l a i n enamel s u r f aces Pb, Cd C895" C872" TABLE 3.38.6 BlOLOGICAL, BOTANICAL AND FOODS ~~ ~ N a t r i x A n a l y t e AMC AOAC I so I UPAC MAFF Animal feeds Ca, Cu, Fe 7.09 1 ( Mg,Mn,Zn TC/34/SCI O(l) D i s t i l l e d l i q u o r s Cu,Fe 9.029(1) Foods cu Ref.G(l) Hg 25. 083(3) Ref. H ( 3 ) Pb 25.044" Sn 25.136'l) Zn 25.150(1) F i s h Pb 25.068") F r u i t & vegetables Zn DIS6636'l) M i l k Pb 25.063" Organic m a t t e r Cd Ref.A,B(') N i Ref. C" Se Ref. D ( 4 ) Sb Ref. E ( 4 ) Zn Ref. F( Cd Ca 3.006(l) co cu 3.006 ( ' ) P l a n t sMethodology TABLE 3.3B.6 BIOLOGICAL, BOTANICAL AND FOODS ( c o n t i n u e d ) 127 M a t r i x A n a l y t e AMC AOAC I so I UPAC MAFF Tea Wines Pb Mn N i K Na Zn Mg 3.006) 3.006 3.006' 3.006' Hg Cd, N i Cu, Fe 25.031 ( ' ) 11.021 ( I ) A.A n a l y s t , 1969, 4, 1153 E. A n a l y s t , 1980, 105, 66 B. A n a l y s t , 1975, 100, 761 F. A n a l y s t , 1973, 98, 458 c. A n a l y s t , 1979, 104, 1070 G. Pure A p p l . Chem., 1979, 51, 385 D. A n a l y s t , 1979, 104, 778 H. Pure Appl.Chem., 1979, 51, 2527 TABLE 3.3B. 7 CLINICAL RATERIALS M a t r i x A n a l y t e BCR I UPAC NBS Blood serum Ca Ref .A(' 260-36 l: n L i Na Blood serum, u r i n e N i LOU-OJ . 260-69" j 260-60' 5, Ref. B(') ~~ ~~ A. J . C l i n . Chem. C l i n . Biochem., 1981, 2, 413 B. Pure A p p l . Chem., 1981, 2, 77128 Analytical A tomic Spectroscopy v, a v, 3 W 0 n 0 m c-( w v, I Q a W Ln m E 5 a 4 n a a, c, 7 m c a X L c, 5 z .r n 7 v n E v v v w v w v w w w v w w w v www N N w - W O l n m m W O W l n m W N M W ~ O O M O - 7 7 7 7 N m e m m e e e NNNNNNNNNNNNNNN NNN n - n l n - 7 v v v W - N N - r - e m 6 3 - n m n nMethodology 129 m a m 3 W 0 n s: r( W m I Q, W m M E I- v, a 4 a 4- W 4 h 4 C 7 a X L c, 4 E '7 v m r- N WWWV cnr-cnm FtmcDu3 "NN vv v v w v O N mcnwcn r - m c o b c o o 3 NN NNNN n r-- W cn In c - c v T- m u3 r- n n N nn v -- cn Nu3 cn ww ? m e m -- n aJ u 4 L c , 4 z u7 l n L c, Q W C C 4 l n w w 4 w E E 3 C130 Analytical Atomic Spectroscopy 1 2 4 8 9 10 11 1 2 7 8 9 10 11 12 13 14 15 TABLE 3.3C SUPPLIERS OF SPECTROGRAPHIC GRAPHITE ELECTRODES Baird Corporation Inc., 125 Middlesex Turnpike, Bedford, MA 01 730, U.S.A.Carbon Products D i v i s i o n , Union Carbide Corp., 270 Park Avenue, New York, NY 10017, U.S.A. (ARL Ltd., Wingate Road, Luton, Beds, England).Labtest Equipment Co., 11328 La Grange Avenue, Los Angeles, CA 90025, U.S.A. Johnson Matthey Chemicals Ltd., Orchard Road, Royston, Herts, SG8 5HE, England Le Carbone (GB) Ltd., Portslade, Sussex, England. Le Carbone Lorraine, 37-41 rue Jean-Haures, 92231 Gennevilliers, France.Instrumentation Laboratory (UK) Ltd., K e l v i n Close, Birchwood, Warrington, Cheshire WA3 7PB, England. Zebac Inc., P.O. Box 345, Bevea, OH 44017, U.S.A. R i ngsdorffe-Werke GmbH, 53 Bonn-Bad Godesberg, West Germany (Mining & Chemical Products Ltd., Alperton, Wembley, Middlesex, HA0 4PE, England). Spex I n d u s t r i e s Inc., 3880 Park Avenue. Metuchen, NJ 08840, U.S.A. (Glen Creston, 16 Dalston Gardens, Stanmore, Middlesex, HA7 lDA, England). U l t r a Carbon Corp., P.O. Box 747, Bay C i t y , M I 48706, U.S.A. (Heyden & Son Ltd., Spectrum House, Alderton Crescent, London NW4, England). TABLE 3.3D SUPPLIERS OF STANDARD METAL SOLUTIONS (MS) AND REAGENTS (R) FOR AAS A l d r i c h Chemical Co. Inc., 940 W. S t . Paul Avenue, Milwaukee, W I 53233, U.S.A. (R). J.T. Baker Chemical Co., 222 Red School Lane, P h i l l i p s b u r g , NJ 08865, U.S.A. (G, R). Barnes Engineering Co., 30 Commerce Road, Stamford, CO 06902, U.S.A. (MS). BDH Chemicals Ltd., Poole. Dorset BH12 4NN, England (MS, R ) Bio-Rad Laboratories, 2200 Wright Avenue, Richmand, CA 94804, U.S.A. (MS) Carlo Erba, D i v i s i o n e Chimica I n d u s t r i a l e , Via C. Imbonati 24, 20159 Milano, I t a l y (MS) Eastman Organic Chemicals, Eastman Kodak Co., 343 S t a t e Street, Rochester, NY 14650, U.S.A. ( R ) Fisons S c i e n t i f i c Apparatus Ltd., Bishop Meadow Road, Loughborough, Leics, L E l l ORG, England (MS, R ) Harleco, Div. o f American Hospital Supply Corp., 60th and Woodland Avenues, Philadelphia, PA 19143, U.S.A. (MS) V.A. Howe & Co. Ltd., 88 Peterborough Road, London, SW6 3EP, England (MS) Instrumentation Laboratory Inc., 113 Hartwell Avenue, Lexington, MA 02173, U.S.A. (MS) Johnson Matthey Chemicals Ltd., Orchard Road, Royston, Herts, SG8 5HE, England (R) Koch-Light Laboratories Ltd., Colnbrook, Bucks, England ( R ) (Anderman & Co. Ltd., Central Avenue, East Molesey, Surrey KT8 OQZ, England) May Z Baker Ltd., Dagenham, Essex RMlO 7XS, England (R) E. klerck, D 61 Darnstadt, West Germany ( R )Methodology 131 16 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Spex I n d u s t r i e s Inc., 3880 Park Avenue, Metuchen, NJ 08840, U.S.A. (MS) ALFA D i v i s i o n , Ventron Corp., 152 Andover S t r e e t , Danvers, MA 01923, U.S.A. (MS) (Glen Creston, 16 D a l s t o n Gardens, Stanmore, Middlesex, HA7 I D A , England) TABLE 3.3E SUPPLIERS OF ORGANOMETALLIC STANDARDS Angstrom Inc., P.O. Box 248, B e l l e v i l l e , M I 48111, U.S.A. B a i r d C o r p o r a t i o n Inc., 125 Middlesex Turnpike, Bedford, MA 01730, U.S.A. J.T. Baker Chemical Co., 222 Red School Lane, P h i l l i p s b u r g , NJ 08865, U. S.A. BDH Chemicals Ltd.. Poole, Dorset BH12 4". England. B u r t $ Harvey Ltd., Brettenham House, Lancaster Place, Strand, London WC2, England. C a r l o Erba, D i v i s i o n e Chimica I n d u s t r i a l e , Via C. Imbonati 24, 20159 Milano, I t a l y . Conostan Div., C o n t i n e n t a l O i l Co., P.O. Drawer 1267, Ponca C i t y , OK 74601, U.S.A. Durham Raw M a t e r i a l s Ltd., 1-4 Great Tower S t r e e t , London EC3R 5AB. England. Rochester, Eastman Organic Chemicals, Eastman Kodak Co., 343 S t a t e S t r e e t , NY 14650, U.S.A. E. Merck, D 61 Darmstadt, West Germany. MBH A n a l y t i c a l Ltd., S t a t i o n House, P o t t e r s Bar, Herts, EN6 IAL, D i v i s i o n o f Chemical Standards, N a t i o n a l P h y s i c a l Laboratory, Middlesex TWll OLW, England. N a t i o n a l Spectrographic L a b o r a t o r i e s Inc., 19500 South M i Cleveland, OH 44128, U.S.A. N a t i o n a l Bureau o f Standards, O f f i c e o f Standard Reference Washington, DC 20234, U.S.A. Eng and. edd ngton, es Road, M a t e r i a l s . Research O r g a n i c / I n o r g a n i c Chemical Corp., 11686 Sheldon S t r e e t , Sun V a l l e y , CA 91352, U.S.A. ALFA D i v i s i o n , Ventron Corp., 152 Andover S t r e e t , Danvers, MA 01923, U.S.A. (Glen Creston, 16 D a l s t o n Gardens, Stanmore, Middlesex, HA7 lDA, England).

ISSN:0306-1353    

DOI:10.1039/AA9841400095

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

CHAPTER 4 Ap pl i cations EXPLANATION OF THE TABLES Each o f t h e A p p l i c a t i o n s Sections, 4.1 t o 4.9, i s accompanied by a Table which summarizes t h e p r i n c i p a l a n a l y t i c a l f e a t u r e s o f t h e r e f e r e n c e s from which t h e corresponding S e c t i o n i s compiled. A l l r e l e v a n t r e f e r e n c e s a r e i n c l u d e d i n t h e a p p r o p r i a t e Table, w h i l e t h e accompanying t e x t discusses o n l y t h e more noteworthy c o n t r i b u t i o n s .These A p p l i c a t i o n s Tables form a convenient source o f i n f o r m a t i o n f o r a n a l y s t s i n t e r e s t e d i n p a r t i c u l a r elements. m a t r i c e s , sample treatments, o r a t o m i z a t i o n systems. I n many cases, s u f f i c i e n t d e t a i l i s g i v e n f o r t h e a n a l y t i c a l procedure t o be f o l l o w e d : absence o f such d e t a i l u s u a l l y means t h a t t h e i n f o r m a t i o n was n o t d i r e c t l y a v a i l a b l e t o t h e c o m p i l e r o f t h e Table, and t h e o r i g i n a l r e f e r e n c e should be consulted.The key t o t h e Tables i s g i v e n below.ELEMENT X/nm MATRIX CONCENTRATION TECH. ATOM I ZATION ANALYTE SAPlP L E TREAT ME NT REF. The elements determined a r e l i s t e d i n a l p h a b e t i c a l o r d e r o f chemical symbol, except t h a t , f o r space economy, m u l t i - element a p p l i c a t i o n s ( 5 elements o r more) a r e g i v e n a t t h e end o f some Tables. The wavelength, i n nanometres, a t which t h e a n a l y s i s was p e r f ormed.An i n d i c a t i o n , n e c e s s a r i l y b r i e f , o f t h e m a t e r i a l analysed. The c o n c e n t r a t i o n rcnge o r l e v e l o f t h e element i n t h e o r i g i n a l m a t r i x , expressed as ug f o r s o l i d s . -1 f o r s o l i d s and mg 1-I The atomic spectrometry technique i s i n d i c a t e d by A (absorp- t i o n ) , E (emission), o r F ( f l u o r e s c e n c e ) .The a t o m i z a t i o n process i s i n d i c a t e d by A ( a r c ) , S ( s p a r k ) , F ( f l a m e ) , o r P (plasma), u s u a l l y w i t h some a d d i t i o n a l d e s c r i p t i v e d e t a i l , e.g., F, Air/C2H2 o r P, I C P . The form o f t h e sample, as presented t o t h e instrument, i s i n d i c a t e d by S ( s o l i d ) , L ( l i q u i d ) , o r G (gas o r vapour). A b r i e f i n d i c a t i o n i s g i v e n o f t h e sample pre-treatment r e q u i r e d t o produce t h e a n a l y t e . The number r e f e r s t o t h e main Reference s e c t i o n , which g i v e s t h e t i t l e o f t h e paper and t h e name(s) o f t h e a u t h o r ( s ) , ~i t h address. 133

ISSN:0306-1353    

DOI:10.1039/AA9841400133

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

134 Analytical A tomic Spectroscopy 4.1 ChEidICALS 4.1.1 Petroleum and Petroleum Products The f i e l d o f m e t a l s a n a l y s i s i n petroleum and petroleum products has now reached a s t a t e of c o n s i d e r a b l e m a t u r i t y . T h i s i s r e f l e c t e d i n fewer p u b l i c a t i o n s c o n t a i n i n g genuine i n i t i a t i v e s and t h e appearance o f more review s t y l e papers.De l a Guardia and Salvador (1852) have produced a c r i t i c a l r e v i e w o f t h e use o f FAAS f o r t h e d e t e r m i n a t i o n o f metals i n l u b r i c a t i n g o i l s : a l t e r n a t i v e methods o f sample p r e p a r a t i o n a r e d e s c r i b e d and discussed. On t h e same t o p i c , E i s e n t r u t e t a l . (1240) d e s c r i b e d t h e c o n c l u s i o n s reached by t h e U n i t e d S t a t e s A i r Force on t h e most a p p r o p r i a t e techniques f o r t h e a n a l y s i s o f used l u b r i c a t i n g o i l s .The most used techniques a r e FAAS and AES w i t h t h e r o t a t i n g d i s c e l e c t r o d e . However, t h e i n e f f i c i e n t d e t e c t i o n o f p a r t i c u l a t e m a t t e r above 5 um has l e d t o a move towards t h e use of ETA-AAS.There are several standard methods a v a i l a b l e f o r t h e d e t e r m i n a t i o n o f Pb i n gasoline. These have been evaluated and reviewed by H o l d i n g and Palmer (935). I n a review c o n t a i n i n g 77 references, Gonzalez and Rodriquez (1063) considered t h e a n a l y t i c a l techniques used f o r t h e d e t e r m i n a t i o n o f m e t a l l i c elements i n crude o i l s and by-products.One problem i n t h e a p p l i c a t i o n o f ICP-OES t o t h e a n a l y s i s o f petroleum and petroleum p r o d u c t s has been t h e i n a b i l i t y o f t h e technique t o cope w i t h t h e v a r i o u s o r g a n i c s o l v e n t s used as d i l u e n t s f o r t h e sample m a t e r i a l .B a r r e t t and Pruszkowska (2117) i n v e s t i g a t e d t h e e f f e c t s o f such parameters as i n c i d e n t power, n e b u l i z e r gas f l o w and diameter of t h e i n j e c t o r t u b e on background and a n a l y t e emission, when u s i n g s o l v e n t s such as M I B K , kerosene, xylene o r chloroform. The automatic i n j e c t i o n and d i l u t i o n system ( A I D S ) , r e p o r t e d by Evans and Klueppel (C126, C1330, C1546), f o r use w i t h ICP-OES, may prove t o be v e r y u s e f u l i n t h i s area o f work, where many samples and l a r g e volumes o f v o l a t i l e s o l v e n t s a r e common. 4.1.1.1 Petroleum F u r t h e r work on t h e c h a r a c t e r i z a t i o n and f i n g e r p r i n t i n g o f V p o r p h y r i n and non-porphyrin species i n heavy crude petroleum (see ARAAS, 1983, 13, 136) has been c a r r i e d o u t by Komlenic e t a l .(693, 2500). The use o f ETA-AAS as aApplications 135 d e t e c t o r f o r HPLC u s i n g s i z e e x c l u s i o n chromatography enabled c a t e g o r i z a t i o n o f t h e p o r p h y r i n and non-porphyrin species.They concluded t h a t much o f t h e V (and N i ) i n t h e crude o i l s was present as low m o l e c u l a r w e i g h t complexes (=, non-porphyrin), which c o u l d be separated by HPLC. Hausler (C1398) used ICP-OES as a d e t e c t o r f o r s i z e e x c l u s i o n chromatography, w i t h a view t o d e t e r m i n i n g t h e m o l e c u l a r s i z e d i s t r i b u t i o n o f Ni, S and V species i n heavy petroleum crudes.The mean m o l e c u l a r s i z e o f t h e S species was s i g n i f i c a n t l y lower t h a n t h a t o f t h e V. The t e c h n i q u e o f emulsion f o r m a t i o n was a p p l i e d t o t h e d e t e r m i n a t i o n o f N i i n f u e l o i l s by De l a Guardia and Lizondo (1236). A f t e r e m u l s i f i c a t i o n , t h e N i was determined by FAAS i n an air/C2H2 flame and r e s u l t s were claimed t o agree w i t h t h e ASTM a s h i n g procedure.Other Spanish workers (794) developed an i o n - p a i r e x t r a c t i o n procedure f o r t h e d e t e r m i n a t i o n o f V i n petroleum and d e r i v a t i v e s i n which t h e V was e x t r a c t e d as a benzohydroxamic a c i d complex and determined by FAAS i n t h e M20/C2H2 flame.Again t h e method was claimed t o be comparable w i t h t h e o f f i c i a l ASTM procedure. The a p p l i c a t i o n o f ICP-AFS t o t h e a n a l y s i s o f petroleum products was r e p o r t e d by Lancione and Drew (C37, C1949). As w i t h ICP-OES t h e e f f e c t s o f sample v i s c o s i t y and plasma l u m i n o s i t y were v e r y i m p o r t a n t parameters which r e q u i r e d c a r e f u l c o n t r o l f o r a c c u r a t e a n a l y s i s . 4.1.1.2 L u b r i c a t i n g O i l s The use o f emulsion formation, p r i o r t o AAS a n a l y s i s , has once again r e c e i v e d a t t e n t i o n . Salvador e t a l . (1266) d e s c r i b e d a procedure where t h e o i l was mixed w i t h HF and HN03 t o d i s s o l v e p a r t i c u l a t e matter, p r i o r t o emulsion f o r m a t i o n w i t h a nonyl phenol e t h o x y l a t e .I r o n was determined by FAAS i n an air/C2H2 flame and t h e method was claimed t o be i n s e n s i t i v e t o p a r t i c l e s i z e e f f e c t s . I n a more d i r e c t approach Hou e t a l . (936) determined Zn by FAAS a f t e r e m u l s i f i c a t i o n o f t h e l u b r i c a t i n g o i l , w i t h no pretreatment.I n t e r - ferences from Ba, Ca and Pb were claimed t o be minimal, b u t no mention was made o f p a r t i c l e s i z e e f f e c t s . A r f e l l i (811) claimed t h a t emulsion f o r m a t i o n i n t h i s a p p l i c a t i o n avoided losses i n h e r e n t i n ashing procedures and was s a f e r t h a n d i l u t i o n w i t h flammable solvents.A comparison of r e s u l t s f o r t h e d e t e r m i n a t i o n o f wear m e t a l s i n l u b r i c a t i n g o i l s by FAAS and ICP-OES was r e p o r t e d by K i n g e t a l . (1854). They concluded t h a t r e s u l t s compared w e l l , b u t t h a t ICP-OES has much t o o f f e r i n g r e a t e r freedom from i n t e r f e r e n c e , g r e a t e r l i n e a r working ranges and b e t t e r s e n s i t i v - i t i e s f o r c e r t a i n elements. 4.1.1.3 Gasol i ne F u r t h e r work on t h e use o f HPLC coupled t o ICP-OES, f o r t h e d e t e r m i n a t i o n of i n d i v i d u a l t e t r a a l k y l - l e a d species (see AR,4AS, 1983, 13, 138) has been performed136 Analytical Atomic Spectroscopy by Ibrahim and Caruso (2617).Detection limits of 42 and 212 ppb were reported for tetramethyl- and tetraethyl-lead. respectively. Another contribution from the same authors (C1400) reported the use of a glass frit nebulizer, for ICP-OES, in order to increase the range of solvents that could be used as HPLC mobile phases.High concentrations of methanol and acetonitrile could be tolerated and this greatly improved the chromatographic performance. Although use of GC coupled to FAAS for the determination of alkyl Pb species has been accepted routine practice for some years, several authors still report on its use. 4.1.2 Chemical and Miscellaneous Applications A review has appeared on hydride generation techniques as they apply to AAS, AFS and ICP-OES (555).This cites 327 references and covers the generation, manipulation and atomization of the hydrides. The use of molecular absorbance in ETA-AAS for the determination of non-metals such as Br, C1, F, I and S in semiconductor materials was reported by Dittrich et al. (912, 2339). Japanese workers (761) utilized atomic absorption in a novel manner by measuring the Fe concentration in the vapour stream used to coat a polymer substrate for magnetic tape production.In this way the thickness of the ferromagnetic layer could be controlled. Fusi and Burgess (C1561) used an ICP-AFS procedure for the determination of As, Ba, Cd, Cr, Hg, Pb, Sb, and Se in paints and surface coatings where freedom from chemical and spectral interferences were amongst the benefits claimed. 4.1.2.1 Atomic Absorption Methods The layer by layer analysis of semiconductor materials has again received attention using FAAS as the analytical finish. Yudelevich et al. (2112, 2539) described etching procedures for the determination of the major elements in lead tin telluride and lead tin selenide single crystals. I n both cases Br2/HBr/H20 solutions were utilized as etchants.Yudelevich and co-workers (914) also reported methods for the determination of 25 elements in AIIIBV semiconducting materials, silicon and germanium. The paper described the use of mechanical separation of layers, chemical etching and etching after anodic oxidation. Determination of trace levels of Cr in gallium arsenide by ETA-AAS was proposed by Taddia and Lanza (1794), the matrix being dissolved i n 50% aqua regia.Fabec and Ruschak (1850) investigated interference effects in the FAAS determination of T i in silica/alumina fluid catalytic cracking catalysts. Addition of A1 and La to samples and standards was found to eliminate the need for matrix matching for the N20/C2H2 flame. The behaviour of Rh in FAAS is notoriously dependent on solvent and Rh species. Belikova (733) investigated the optimum conditions for the conversion of homogeneous and heterogeneousApplications 137 rhodium c a t a l y s t s t o water soluble forms and claimed t h a t t h e a d d i t i o n o f La could be used t o c o n t r o l m a t r i x e f f e c t s .Taddia (789) claimed t h a t t h e use of L'vov p l a t f o r m ETA-AAS was successful i n t h e e l i m i n a t i o n o f t h e suppressive i n t e r f e r e n c e o f Si on A l , a l l o w i n g the determination o f A1 i n a s i l i c o n matrix. 4.1.2.2 Atomic Emission Methods I n t h e determination o f t h e P t group elements i n alumina-based c a t a l y s t s by DCP-OES, t h e m a t r i x element i s known t o cause enhancement errors.Fox (1829) claimed t h a t t h e a d d i t i o n o f Li and La e l i m i n a t e d t h e e f f e c t , a l l o w i n g t h e determination o f Pd, P t and Rh. Fabec and Ruschak (183) determined percent l e v e l s o f A l , Co, La, and Ru i n alumina-based c a t a l y s t s by ICP-OES a f t e r d i g e s t i o n o f t h e m a t r i x i n H SO /HC1, i n t e r f e r e n c e s being claimed t o be minimal. 2 4 The determination o f non-metals by ICP-OES once again received a t t e n t i o n . For example, t h e a n a l y s i s o f cosmetic products f o r S, by ICP-OES, was d e t a i l e d by B e t t e r 0 e t a l . (1237). L i q u i d samples were aspirated d i r e c t l y , emulsions a f t e r d i l u t i o n w i t h water using a standard a d d i t i o n procedure.Dipasquale and Casetta (1886) determined S i n polymeric m a t e r i a l s by ICP-OES a f t e r c h a r r i n g f o l l o w i n g Schoninger's method and absorbing t h e gaseous products i n water/H202 and using t h e 182.04 nm l i n e . Hausler (C1329) used ICP-OES w i t h purged o p t i c s t o determine N, a t 174.27 nm, i n xylene-soluble materials. It was found necessary t o use an i n e r t gas p u r i f i e r f o r the A r plasma gas i n order t o remove N, 0, water and organics. 4.1.2.3 Hybrid Techniques The appearance o f papers d e t a i l i n g a p p l i c a t i o n s o f gas chromatography-microwave induced plasmas. noted w i t h some s u r p r i s e i n 1983 (see ARAAS, 1983, 13, 139), continues unabated. The technique has apparently been applied successfully t o t h e determination o f Br i n solvents (2632). p o l y c h l o r i n a t e d biphenyls (261).halogenated hydrocarbons (C1390, 2292), oxygenated compounds (C1391) and inorganic compounds (C1387). Hazen e t a l . (C87) described "tagging" procedures t o enable t h e M I P t o be used as a more u n i v e r s a l GC detector. For example, c h l o r o d i f l u o r o a c e t i c anhydride can be used t o a c e t y l a t e alcohols, t h i o l s and amines, a l l o w i n g t h e use o f Cl/F r a t i o s f o r analysis. I s r a e l 1 and Barnes (775) a p p l i e d t h e flow i n j e c t i o n technique i n combination w i t h ICP-OES t o t h e determination o f S i i n phosphoric acid.For As i n glycerine, Barnes and co-workers (C1294) u t i l i z e d F I , i n combination w i t h hydride generation, p r i o r t o ICP-OES analysis.This approach allowed t h e determination o f As i n t h e 0.5 t o 7 ug g-' range. A successful combination o f i o n chromatography and FAAS was d e t a i l e d by Pettersen (2145). Chromate i n lignosulphonates (e.g., d r i l l i n g f l u i d a d d i t i v e s ) could be determined as the second o f two Cr-containing138 Analytical Atomic Spectroscopy chromatographic peaks. 4.1.2.4 I n d i r e c t Methods Papers on t h i s t o p i c were s i g n i f i c a n t l y reduced i n number from t h e p r e v i o u s year. Pharmaceutical a p p l i c a t i o n s were p r e v a l e n t w i t h procedures appearing f o r t h e d e t e r m i n a t i o n o f sulphonamides (1052).ephedrine (758). p i p e t h a n a t e h y d r o c h l o r i d e (757) and bromazepam i n drugs (509). I n a l l cases r e a c t i o n w i t h s p e c i f i c reagents t o form metal complexes, and subsequent d e t e r m i n a t i o n o f t h e metals, was t h e b a s i s o f t h e method. On a more c o n v e n t i o n a l l e v e l some a u t h o r s s t i l l r e p o r t t h e d e t e r m i n a t i o n o f P as Sb i n t h e phosphoantimonylmolybdate complex (1757) and as Mo i n t h e phos- phomolybdate complexes (2555).b =: 2 TABLE 4.1A PETROLEUM AND PETROLEUM PRODUCTS T e c h n i q u e , A n a l y t e Form Element A/nm M a t r i x C o n c e n t r a t i o n A t o m i z a t i o n , Sample t r e a t m e n t --- Ca - Ca - Cd c o c u - c u - Fe - F e - F e 248.3 Fe - L i - Na - N i - L u b r i c a t i n g o i l L u b r i c a t i n g o i l C r u d e o i l , f u e l o i l A v i a t i o n o i l s L u b r i c a t i n g o i l A v i a t i o n o i l s L u b r i c a t i n g o i l L u b r i c a t i n g o i l L u b r i c a t i n g o i l P e t r o l e u m c r u d e s L u b r i c a t i n g g r e a s e L u b r i c a t i n g o i l L u b r i c a t i n g o i l s , s o l v e n t s L u b r i c a t i n g g r e a s e O i l s A , ETA ,L A,F,L A,F,L E , P , ICP, L A,F,Air/C2H2, A , F , Air /C2H2, L L A,F,L A,F,L E , P, ICP ,L Combustion i n oxygen bomb, d i s s o l u t i o n of p r o d u c t i n HC1, Ba and La added t o p r e v e n t i n t e r f e r e n c e from s u l p h a t e a n d p h o s p h a t e E m u l s i f i c a t i o n i n a q u e o u s d i l u t e a c i d c o n t a i n i n g a s u r f a c t a n t Dry a s h i n g w i t h H2S04, d i s s o l u t i o n o f r e s i d u e i n a q u e o u s HC1 D i s s o l u t i o n i n THF; s t a n d a r d s p r e p a r e d from metal s a l t s i n oil/THF Samples d i l u t e d w i t h a n a c i d i c s o l u t i o n o f b u t y l acetate, e t h a n o l and H 0 p r i o r t o a s p i r a t i o n 2 S e e Co, r e f . 810 S e e Cu, r e f . 542 S i m p l e d i l u t i o n Fe d i s s o l v e d u s i n g HF/HNO 3 o i l - w a t e r e m u l s i o n u s i n g a n o n y l phenol e t h o x y l a t e p r i o r t o f o r m a t i o n o f a n - Samples d i s s o l v e d i n g l a c i a l acetic a c i d S e e Ca, r e f . 470 S e e L i , r e f . 500 Sample m i n e r a l i z e d w i t h a c i d , a s h e d and d i s s o l v e d i n n i t r i c a c i d 470 811 544 810 542 810 542 749 1266 2076 500 4 7 0 C2466 500 C404 G; \DTABLE 4.1A PETROLEUM AND PETROLEUM PRODUCTS ( c o n t i n u e d ) c P 0 N i 232 N i - N i 232.0 N i - N i 232.0 P 213.6 214.9 Pb 283.3 Pb Pb - Pb 405.78 Pb - S 180.7 182.0 182.6 S 384 V Gas o i l A v i a t i o n o i l s F u e l o i l s Petroleum c r u d e s Petroleum c r u d e s and a s p h a l t e n e s R e s i d u a l and d i s t i l l a t e o i l , e d i b l e o i l Gasoline Gasoline Gaso 1 i ne Gasoline Gasoline R e s i d u a l and d i s t i l l a t e o i l , e d i b l e o i l Fuel o i l s O i l s A,F,Air/C2H2, A,F,L See Co, r e f . 810 Sample d i s s o l v e d i n white s p i r i t L 642 810 >0.05 mg/l A,F,Air/C2H2, Aqueous emulsion formed u s i n g s u r f a c t a n t 1236 L - A , L F , Air /C2H2, - 2076 ug/g A , ETA ,L E x t r a c t s i n p y r i d i n e d i l u t e d with CH C1 and i n j e c t e d 2500 i n t o HPLC-AAS system t o determine s p z c i e s p r e s e n t - E,P,ICP,L D i s s o l u t i o n i n o r g a n i c s o l v e n t C89 0.05-0.50 g / 1 A,F,Air/C2H2, D i l u t e w i t h MIBK, add I and a l i q u i d a n i o n 935 L exchanger; s t a n d a r d s przpared from PbC12 p r i o r t o d i r e c t i n t r o d u c t i o n t o t h e plasma via a g l a s s f r i t n e b u l i z e r - E P ICP , L Alkyl Pb s p e c i e s s e p a r a t e d by r e v e r s e d phase HPLC C1400 - A,FtL GC-AAS used t o determine t e t r a - m e t h y l and - e t h y l Pb 2019 - E , P , ICP ,L HPLC-ICP coupled t o a l l o w i n d i v i d u a l d e t e r m i n a t i o n 2617 of Pb s p e c i e s b 1-1000 mg/l E,F,Air/H2,L GC used t o determine t e t r a e t h y l Pb p r i o r t o FAES 2619 8 d e t e c t i o n 2.E, P, ICP, L E , MECA , L A,F,L See P, r e f . C89 Sample heated w i t h Devarda's a l l o y i n HC1 t o g e n e r a t e H2S, emission of S2 monitored See N i , r e f .C404 C89 C401 C404b TABLE 4.1A PETROLEUM AND PETROLEUM PRODlJCTS ( c o n t i n u e d ) s -. V 318.4 P e t r o l e u m and d e r i v a t i v e s V - P e t r o l e urn V 318.4 P e t r o l e u m c r u d e s c r u d e s and a s p h a l t e n e s Zn - L u b r i c a t i n g o i l Zn - L u b r i c a t i n g Zn - L u b r i c a t i n g o i l Zn - L u b r i c a t i n g o i l g r e a s e a d d i t i v e s V a r i o u s - O i l s V a r i o u s - L u b r i c a t i n g o i l V a r i o u s - Lu b r ica t irig o i 1 V a r i o u s - C r u d e ( 7 ) p e t r o l e u m V a r i o u s - Crude o i l s , V a r i o u s - L u b r i c a t i n g o i l V a r i o u s - L u b r i c a t i n g o i l V a r i o u s - L u b r i c a t i n g o i l V a r i o u s - L u b r i c a t i n g o i l b y p r o d u c t s ( 7 ) (22) (28) 15-180 mg/kg A,F,N20/C2H2, L 0.0004-0.02% A,F,N20/C2H2, L '1 vg/g A,ETA,L v 5 ug/g A , F,Air/C2H2, L - F, P , ICP ,L - E,P,ICP,- - E,A,D.c.,S A , ETA ,- - A , F , A i r /C2H2, L - - - E , P , ICP ,L E , P I ICP , L - - A,F o r ETA,L - A o r E,F o r P , L Sample a s h e d w i t h H SO , d i g e s t e d w i t h H2S04/HN03 a n d n e u t r a l i z e d w i t 2 NiOH - S e e N i , r e f . 2500 S e e Ca, r e f . 470 S e e L i , r e f . 500 Sample d i l u t e d w i t h x y l e n e a n d a c e t i c a c i d L u b r i c a t i n g o i l is e m u l s i f - i e d p r i o r t o n e b u l i z a t i o n , s t a n d a r d s p r e p a r e d by e m u l s i f y i n g a q u e o u s Zn s o l u t i o n s D i l u t i o n i n o r g a n i c s o l v e n t - Samples a s h e d D i s s o l v e i n t o l u e n e - a c e t i c a c i d mixed s o l v e n t , c a l i b r a t e by s t a n d a r d a d d i t i o n Review D i s s o l u t i o n i n MIBK, x y l e n e o r k e r o s e n e A u t o m a t i c i n j e c t i o n and d i l u t i o n s y s t e m s (AIDS) based o n FIA p r i n c i p l e s ( C r , Cu, F e , Mn, N i , S i , V) Review Comparison of ICP-OES w i t h AAS; o i l d i l u t e d w i t h x y l e n e i n b o t h cases 794 a s 2076 ' 2500 470 500 54 1 936 C338 584 589 809 1063 C1216 C 1546 1852 1854 - P c- P TABLE 4.1A PETROLEUM AND PETROLEUM PRODUCTS (continued) N Various - Lubricating oil - E, P, ICP ,L - C1913 Various - O i l s >3 nglg A, ETA, L Direct ashing in ETA (As, Cd, Pb, Sn) 2018 ( 4 ) Various - Fuel and - E, P I ICP, L Oils diluted with xylene, kerosene or MIBK prior 2117 (10) lubricating oil to aspirationb TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS Q 9 T e c h n i q u e , B R e f . % A n a l y t e Form LY - Element h/nm Matrix C o n c e n t r a t i o n A t o m i z a t i o n , Sample t r e a t m e n t --- A 1 396.2 A s - A s 193.7 Au - B 249.7 B 249.7 Ba 553.5 Br - Cyanide s o l u t i o n s Jewellers sweeps C h l o r o b u t y l r u b b e r S i l i c o n Po tass i urn c h l o r i d e h y d r o t h e r m a l r e a c t i o n f l u i d Aluminium a d j u v a n t s C o o l i n g tower t i m b e r s G l y c e r i n e Jewellers s w e e p s Ammo n i um c h l o r i d e e l e c t r o l y t e E n g i n e c o o l a n t Calcium c a r b o n a t e O r g a n i c compounds - ug/g-% - 20.2 ug/g 0.01-4 mg/l - - 0.5-7 Ug/g - - 0.06% 4-45 ug/g g A ,ETA, L A,ETA,- A,ETA,L E,A,A.c.,L E , P , DCP , L A IF ,N20/C2H2 , L E , P ,MIP , L Samples d i s s o l v e d i n s o l u t i o n o f KI a n d c y a n i d e Ashing and d i g e s t i o n i n HC1 L'vov p l a t f o r m u s e d t o r e d u c e i n t e r f e r e n c e s MIBK e x t r a c t i o n , MIBK e v a p o r a t e d , r e s i d u e d i s s o l v e d i n d i l u t e H N 0 3 F I A / h y d r i d e g e n e r a t i o n u s e d p r i o r t o ICP S e e Ag, r e f .C2439 Samples mixed w i t h NaCl a n d Mo ( i n t e r n a l s t a n d a r d ) a n d d i l u t e d w i t h water Samples d i l u t e d w i t h d i l u t e acetic a c i d Ba c o - p r e c i p i t a t e d w i t h PbS04, p r e c i p i t a t e d i s s o l v e d i n NH40H s o l u t i o n of EDTA C a p i l l a r y GC u s e d t o s e p a r a t e components which e l u t e d i r e c t l y i n t o MIP 2399 C2439 647 759 1849 2203 1031 C1294 C2439 4 1 5 1753 66 1 2 6 1TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS ( c o n t i n u e d ) - P C - Cd - c1 - C l 413.25 c o - C r - C r - C r 357.9 C r - C r - c u - c u - c u 324.8 c u - c u - E r - Eu - Fe - F e - O r g a n i c compounds P l a s t i c s O r g a n i c compounds Carbon d i o x i d e Luminophors Ground l e a t h e r C o o l i n g tower t i m b e r s Gall i um a r s e n i d e Tanned l e a t h e r L i g n o s u l p h o n a t e d i s p e r s a n t s Semiconducting s i l i c o n Methyl v i o l e t Hydroxy- c a r b o x y l i c a c i d s Cosme t i c s C o o l i n g tower t i m b e r s Y and La o x y s u l p h i d e s Luminophors Lurninophors Semiconducting s i l i c o n g E , P ,MIP , L A , ETA ,L E, P,MIP, 1, E,S,H.v.,G A , - , - A,F,L p , L A or E, F o r A , ETA ,L S e e B r , r e f . 261 3 P l a s t i c s d i s s o l v e d i n d i m e t h y l s u l p h o x i d e and HNO S e e B r , r e f . 261 Sample d i s s o l v e d i n 50% a q u a r e g i a , d i l u t e d t o volume C r d i s s o l v e d by h e a t i n g w i t h H2S04/HN03 AAS u s e d as d e t e c t o r for i o n chronat.ography t o d e t e r m i n e chromate - - P r e c o n c e n t r a t i o n of Cu a t a P t c a t h o d e a n d 3 r e - d i s s o l u t i o n i n HNO 26 1 2142 26 1 526 177 539 1031 1794 2143 2145 C333 51 1 738 ~ $ 1001 1031 & 178 3, 176 f 177 2 0 c333 gH Hg Hg Mg N N Na N i P P P P P Pb Pb Pb b 526 3 TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS ( c o n t i n u e d ) h % 314.34 Carbon d i o x i d e - Cosmet i c p r o d u c t s - C h i n e s e m e d i c i n a l p i l l s 285.2 I n s u l a t i n g 388.34 Carbon d i o x i d e 174.3 X y l e n e s o l u b l e 589 I n s u l a t i n g P u l p s materials P u l p s - Semiconducting s i 1 i.c on - w03 206.8 C h l o r o s i l a n e s , ( S b ) s i l i c a D e t e r g e n t s O r g a n i c compounds O r g a n i c compounds Bismuth Drugs 3 Lead t i n t e l l u r i d e E,S,H.v.,G - A , ETA ,G Sample combusted i n 0 a t 800 "C; Hg c o l l e c t e d o n Au a n d f i n a l l y d e s o r b e d a t 750 *C i n t o flow a b s o r p t i o n c e l l P i l l s d i g e s t e d w i t h H2S04/ H202 A,Cold v a p o u r , A , F , A i r / C H L/S 2 ' E,F,MECA,L E ,MECA, L A , - , - A,F,L A , F ,Air/C2H2, L Decomposition o f p u l p w i t h a 5 : l m i x t u r e of HNO 3 a n d HC104 a t 150-250 "C f o r 1.5 h Samples d i s s o l v e d i n x y l e n e S e e Mg, r e f . 538 F o r m a t i o n a n d s u b s e q u e n t e x t r a c t i o n o f t h e phosphovanadatomolybdate i n t o MIBK C h l o r o s i l a n e s h y d r o l y s e d ; b o t h sample t y p e s t r e a t e d w i t h HF t o remove S i , r e s i d u e d i g e s t e d i n HC104 p r i o r t o e x t r a c t i o n o f phosphoantirnonyl m o l y b d a t e complex i n t o MIBK D e t e r g e n t a s h e d a t 520 "C, a s h d i s s o l v e d i n H 2 0 Samples decomposed by oxygen f l a s k method, P d e t e r m i n e d i n d i r e c t l y as Mo L a y e r by l a y e r e t c h i n g of t h e s i n g l e c r y s t a l w i t h HBr/Br7 d. 646 5 C2484 538 5 2 6 c 1 3 2 9 538 c333 C1691 1757 1839 2173 2555 185 510 2112 P v1L P m TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS ( c o n t i n u e d ) - Pb Gunshot - A,-,L 2491 - r e s i d u e s Pb - Lead t i n % Pd 340.5 Automobile - s e l e n i d e c a t a l y s t P t - Bismuth - P t 306.5 Automobile - c a t a l y s t Rh - Cata 1 y s t s - A,F,Air/C2H2, Layer by layer e t c h i n g of t h e s i n g l e 2539 C a t a l y s t ground t o 60 mesh, l e a c h e d i n 50% H SO 1829 E , P , DCP, L f i l t e r e d and i n s o l u b l e matter d i g e s t e d w i t h HN03/HC1 - 185 L crystal w i t h Br2/HBr/H20 2 4’ A y - 9 - E ,P ,DCP L See Pd, r e f . 1829 A,F,L La used a s s p e c t r o s c o p i c b u f f e r i n aqueous s o l u t i o n Rh 369.2 Automobile - E P , DCP, L See Pd, r e f . 1829 c a t a l y s t 1829 733 1829 Samples a s p i r a t e d d i r e c t l y o r a f t e r d i l u t i o n w i t h H 0 1237 S 182.04 Cosmetic 3-14 mg/l E,P,ICP,L S 182.04 Polymeric 0.7-2.2% E,P ICP, L Schoeninger method used t o c h a r polymer; g a s 1886 2 p r o d u c t s m a t e r i a l s evolved absorbed i n H20/H202 compounds S determined i n d i r e c t l y as Ba S Organic - A,F,L Samples decomposed by oxygen f l a s k method, 2555 - Sb - PVC compositions Sb - Gunshot r e s i d u e s Se - Lead t i n s e l e n i d e - S i H3P04 Sm - Y and La oxysulphides - PVC t r e a t e d w i t h H2SO4! t h e n H 0 added; r e s u l t i n g 2195 $ 2 2 A,F,L a P l i q u i d c o n t a i n i n g a w h i t e p r e c i p i t a t e d i l u t e d w i t h a n a c i d mixture and a n a l y s e d 2.% A,F,Air/C2H2, See Pb, r e f . 2539 E , P , ICP, L E,-,L - L FIA coupled t o ICP 2491 2539 2. $ ? 775 2 Y 178L 13 z7 TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS ( c o n t i n u e d ) 13 Sn - Sn - Sn - Sn 224.6 286.3 Sn - T e 214.3 T i - U - Yb - Zn 328.2 V a r i o u s - ( 3 0 ) ( 6 ) V a r i o u s - V a r i o u s - V a r i o u s - ( 4 ) A n t i f o u l i n g pa i n t s Water, f o o d Or g a n o t i n compounds Lead t i n t e l l u r i d e Lead t i n s e l e n i d e Lead t i n t e l l u r i d e S i l i c a / a l u m i n a b a s e d c a t a l y s t s O r g a n i c s o l u t i o n s Y a n d La o x y s u l p h i d e s Ammonium c h l o r i d e e l e c t r o l y t e CRMs Aqueous s o l u t - i o n s , s i n g l e c r y s t a l s Cesium c h l o r i d e Alumina c a t a l y s t s - A,ETA,L 20-100 ng/g E,P,DCP,L - A , ETA, L 2 A,F,Air/C2H2, 2 A , F , Air /C2H2, % A,F,Air/C2H2, I, L L a1 2 A,F,N20/C2H2, L >0.1 mg/l E,P,ICP,L - E, P, ICP, L - F,ETA,S o r L E,P,ICP,L E , P, ICP , L T r a c e t r i p h e n y l t i n c h l o r i d e e x t r a c t e d i n t o MIBK Combined HPLC, h y d r i d e g e n e r a t i o n ; DCP used t o d e t e r m i n e Sn s p e c i e s Bomb d e c o m p o s i t i o n w i t h H N 0 3 S e e P b , r e f . 2112 S e e P b , r e f . 2539 S e e Pb, r e f . 2112 C a t a l y s t d i s s o l v e d i n d i l u t e H2S04, HF used t o remove S i , A 1 and S i added t o f i n a l s o l u t i o n S e e B, r e f . 415 (Cd i n t e r n a l s t a n d a r d ) F u s e w i t h KOH/K202 - (Ag, Co, Cu, F e , I r , Pb) D i s s o l u t i o n and d i r e c t measurement D i g e s t w i t h 8% H2S04 a n d 10% HC1 ( A l , C o , La, Ru) 934 g, 0 3, C 1529 1863 2112 2539 2112 1850 658 178 415 C116 166 170 183 e P 4‘TABLE 4,lB CHEMICALS AND MISCELLANEOUS MATERIAIS ( c o n t i n u e d ) V a r i o u s (20) V a r i o u s V a r i o u s ( 7 ) ( 4 ) (4) (22) (35) (4) V a r i o u s V a r i o u s V a r i o u s V a r i o u s V a r i o u s V a r i o u s (6) ( 4 ) (9) (6) ( 5 ) V a r i o u s V a r i o u s V a r i o u s V a r i o u s V a r i o u s S i l i c o n B a r i u m s u l p h a t e P e t r o l e u m c a t a l y s t s D r u g s P h o s p h o r u s N u c l e a r s o l u t i o n s Se 1 e n i um S i n g l e c r y s t a l f i l m s P o l y a c r y l a m i d e s o l u t i o n s N i c k e l e l e c t r o l y t e s C a l c i u m o x i d e P a p e r a n d p a p e r p r o d u c t s 0.0005-0.3% S i l v e r b r o m i d e , - s e m i c o n d u c t o r mat er i a 1.s S e m i c o n d u c t o r - ma t e r i a 1 s 0.1-10 lJg/g 0.001-3 Ug/g E,-,S E,A,D.c. ,S E , P , I C P , - A,F,L A , H y d r i d e , E l e m e n t s d e t e r m i n e d o n a l a y e r by l a y e r b a s i s 192 D.c. arc u s e d f o r t h e F r a c t i o n a l d i s t i l l a t i o n o f t h e 455 i m p u r i t i e s : s t a n d a r d s p r e p a r e d by m i x i n g e l e m e n t s or t h e i r o x i d e s w i t h b a r i u m s u l phate - (Co, F e , Mo, N i , P h , I’d, P t ) 543 - ( A S , C d , P b , T1) 550 - (As, H i , Sb, T e ) 606 b A,ETA,L E,Hollow c a t h o d e d i s c h a r g e , S E o r A,F,I, E,A,A.c.,S E,A,D.c.,S A , ETA , L D i l u t e w i t h H 2 0 617 Remove m a t r i x e l e m e n t w i t h hex-1-ene 728 735 - ( F e , Ge, Gd, Y) Direct a s p i r a t i o n o f p o l y m e r s o l u t i o n s 747 P r e c i p i t a t e a n d mix w i t h powdered g r a p h i t e 779 (Ag, A u , P d , Rh) ( C a , K , L i , Mg, Mn, Na) C a r r i e r d i s t i l l a t i o n t e c h n i q u e 860 ( A l , B , C d , C r , L i , Mg, Mn, Na, S i ) P a p e r d i g e s t e d w i t h HNO u n d e r p r e s s u r e or a s h e d 883 w i t h 0 (As, Cd, C u , F e , Hg, P b ) D e t e r m i n e by m e a s u r e m e n t of m o l e c u l a r a b s o r b a n c e s 912 ( B r , C 1 , F, I , S ) 3 S a m p l e s e t c h e d w i t h HNO /HF 914 3L TABLE 4.1B CIIEMICAIS AND MTSCELLANEOUS MATERIALS ( c o n t i n u e d ) "s s 2 V a r i o u s - Z i n c a n d - E,-,S C o , Cu, F e a n d N i e x t r a c t e d i n t o a mixed a l c o h o l s / 1020 8, cadmi um c h l o r o f o r n i s o l v e n t w h i c h is e v a p o r a t e d i n p r e s e n c e 0 s u l p h i d e s of g r a p h i t e ; r e s i d u e t r e a t e d w i t h IiN03, h e a t e d t o ( 4 ) 400-450 " C p r i o r t o s p e c t r o g r a p h j c a n a l y s i s V a r i o u s - E t h y l - E , A , A .c . , - G r a p h i t e e l e c t r o d e s i m p r e g n a t e d w i t h p o l y m e t h y l - 1 0 2 7 (8) sil icates p h e n y l s i l o x a n e ( A l , C u , F e , Mg, Mn, N i , T i , Z n ) (5) t i t a n a t e c r u c i b l e ( C u , Dy, S i , S r , Z n ) V a r i o u s - Bar i um 0.002-0.2% E,P, [CP,L S a m p l e mixed w i t h HC1 a n d h e a t e d i n a p r e s s u r e 1030 V a r i o u s - B o i l e r - d e p o s i t s A,F,L M e t h o d s g i v e n for t h e p r e p a r a t i o n of s o l u t i o n s f o r 1268 t h e d e t e r m i n a t i o n of 1 2 e l e m e n t s V a r i o u s - A n t i f r e e z e - E , P , ICP , L D i l u t e w i t h water c o n t a i n i n g i n t e r n a l s t a n d a r d C1383 ( 4 ) V a r i o u s - N i c k e l ug l e v e l E , A , A .c . , S S a m p l e i s b o i l e d w i t h K l / a s c o r b i c a c i d , mixed w i t h 1 4 8 2 ( 5 ) plat.i n g c h r o m p y r a z o l 11; p r e c i p i t a t e f j l t e r e d a n d mixed e l e c t r o l y t e w i t h g r a p h i t e / G e O a n d Co as i n t e r n a l s t a n d a r d (Ag, A u , P b , P d , %t) V a r i o u s - P a i n t s a n d 3-400 Ug/g F , P , ICP, L Low t e m p e r a t u r e ash w i t h HNO d i s s o l u t i o n or (21561 (8) s u r f a c e d i r e c t l e a c h i n g w i t h d i l u t e 3HC1 c o a t .i ng s ( A s , Ra, C d , C r , Hg, P b , S b , Se) V a r i o u s - ( 6 ) V a r i o u s - V a r i o u s - V a r i o u s - Nickel - p l a t i n g b a t h s A r c h a e o l o g i c a l - ma ter i a Is N u c l e a r r e a c t o r - ma teri a l s F , P , ICP , L - ( C d , C u , C r , F e , P b , Zn) C1565 E or A , - , - - Cl596 E , A , D .c . , S - C1598 High p u r i t y 1-500 p g / l E , P , I C P , I , D i l u t i o n w i t h d o u b l e d i s t i l l e d w a t e r a c i d s C1672 - E o r A,-,- - (Ca, K , Mg, Na) C 1707 V a r i o u s - "202 ( 4 ) - EDTA s u s p e n d e d i n II 0 a n d s o l i d s d i s s o l v e d 1831 - E, P, ICP ,L 2 V a r i o u s - EDTA s o 1 u t i o n s u s i n g NH4011 P a ( 2 8 )TABLE 4.1B CHEMICALS AND MISCELLANEOUS MATERIALS ( c o n t i n u e d ) Var i ous (5) V a r i o u s (12) V a r i o u s (5) (6) V a r i o u s V a r i o u s (21) (5) Var i o u s V a r i o u s (29) V a r i o u s (16) (4) ( 4 ) Var j o u s V a r i o u s V a r i o u s (27) V a r i o u s (6) S e m i c o n d u c t o r c r y s t a l mat er i a 1 s C h e m i c a l s f o r s e m i c o n d u c t o r i n d u s t r y O l e f i n p l a s t i c foams A 1 u m i n i um ammonium s u 1 p h a t e Uranium h e x a f l i i o r i d e N u c l e a r r e a c t i o n t a r g e t mate r i a 1 ( S b ) G r a p h i t e A l k y l Lead compounds R o s i n H y d r o c h l o r i c a c i d , p u r e Enamel l e d c o o k w a r e S i l v e r n i t r a t e 1-100 ng/g A,ETA,L - A or E, P or F o r ETA,L 20.00001% AYF,L - E , P , ICP ,L - E , P , I C P , L - E,A,D.c.,S - E,A,D.c.,S Decompose i n v a p o u r p h a s e d i s s o l u t i o n bomb 1867 ( A l , C r y C u , F e , N i ) - 1884 S a m p l e s w e t a s h e d i n HN03/HC104 ( A l , C a , Co, Mg, Z n ) E x t r a c t w i t h APDC i n MIBK (Cd, C o , Cu, F e , N i , P b ) 2141 2165 Remove m a t r i x w i t h tri(2-ethylhexy1)phosphate 2177 i n h e p t a n e S a m p l e d i s s o l v e d i n HCl/HNO m i x t u r e , c o n v e r t e d t o 2213 b r o m i d e s w i t h HBr; Sb e x t r a c t e d w i t h bis(2-ethylhexy1)phosphate ( A l , C d , C o , P b , T e ) S a m p l e s a s h e d , NaCl/NaF carrier a d d e d a n d 238 Sr(N03)2 a d d e d as b u f f e r Decompose s a m p l e s i n IINO , c o n v e r t t o o x i d e s 2409 a n d mix w i t h g r a p h i t e a n 2 NaCl - ( C r , Cu, F e , Mn) 2585 ~ - ( C a , K , L i , Na) 2599 2 L e a c h w i t h 4% acetic a c i d f o r 24 h 2614 $ S e p a r a t e from t h e m a t r i x by c o n s t a n t p o t e n t i a l 2621 3 3 s. 2. e l e c t r o l y s i s a t 0.3 V ( B i , C u , F e , Mg, Mn, P b ) f 5

ISSN:0306-1353    

DOI:10.1039/AA9841400134

出版商:RSC    

年代:1984

数据来源: RSC