JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRYy DECEMBER 199 1 VOL. 6 283R ATOMIC SPECTROMETRY UPDATE-INDUSTRIAL ANALYSIS METALS CHEMICALS AND ADVANCED MATERIALS John Marshall* and John Carroll ICI plc Wilton Materials Research Centre P.O. Box 90 Middlesbrough Cleveland TS6 8JE UK James S. Crighton 8P Research Centre Chertsey Road Sunbury on Thames Middlesex TW16 7LN UK Summary of Contents 1 Metals 1 .l. Ferrous Metals and Alloys 1.2. Non-ferrous Metals and Alloys Table 1. Summary of Analyses of Metals 2 Chemicals 2.1. Petroleum and Petroleum Products 2.1.1. Crude oil and fractions 2.1.2. Lubricating oils 2.2. Organic Chemicals and Solvents 2.2.1. Chemicals 2.2.2. Solvents 2.3. Inorganic Chemicals and Acids 2.3.1. Chemicals 2.3.2. Acids 2.4. Nuclear Materials 2.5. Process Analysis and Automation Table 2.Summary of Analyses of Chemicals 3 Advanced Materials 3.1. Polymers and Composites 3.2. Semiconductor Materials 3.3. Glasses Ceramics and Refractories 3.3.1. Glasses 3.3.2. Ceramics and Refractories Table 3. Summary of Analyses of Advanced Materials This Atomic Spectrometry Update is the third to appear under the title of ‘Industrial Analysis’. The structure of the review is the same as that used in previous years. The subject matter covered in this review is so diverse that it is difficult to discern broad themes in application or technique development. However pressures continue to be exerted on industrial laboratories to provide information with greater structural content (both of a chemical and physical nature) while at the same time demands are made for higher sample throughput and improved sensitivity.A wide range of techniques are now available for the direct characterisation of solids allowing the integrity of the sample to be maintained. However the issue of response calibration is central to the debate concerning the study of solid structures and a variety of theoretical and empirical methods have been proposed to obviate such difficulties. The determination of chemical structure has become increasingly important as the advantages of using atomic spectometric techniques for chromatographic detection are realised. In order to satisfy demand for greater sensitivity preconcentration and/or extraction procedures continue to be developed and the use of flow injection for automating such procedures is growing.There are also encouraging signs of the development of atomic spectrometric techniques for process control which should lead to a reduction of the amount of routine analysis required. It remains to be seen whether the instruments developed over many years for laboratory work will evolve to meet this challenge. 1. METALS This section of the review covers the analysis of ferrous and non-ferrous metals and alloys by analytical atomic spectro- metry. A summary of analytical methods for the analysis of metals is given in Table 1. in these areas were related to improvements in sample preparation methodologies rather than in method develop- ment for the analytical techniques in question. This perhaps reflects the necessity of presenting the samples to the instruments in solution form and to some extent to the 1 .l.Ferrous Metals and Alloys maturity of these techniques. Details of these procedures are summarised in Table 1. Both AAS and ICP-OES continue to enjoy widespread use in metallurgical analysis. The majority of abstracts received * Review Co-ordinator to whom correspondence should be addressed. The number of applications describing the use of ICP- MS for both ferrous and nonferrous metals analysis show a marked increase compared with those received in previous years reflecting the increasing acceptance of this technique in the metallurgical field. Development of analytical proce-284R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 Table 1 SUMMARY OF THE ANALYSES OF METALS Technique; atomization; analyte form* AA;F;L ZAA;ETA,S AA;F;L Element Matrix Ag Copper-based alloys Ag Copper metal Ag Copper alloys Reference 9111330 9 112509 9 1/25 1 9 Sample treatmentlcomments Ag separated from matrix using HPLC Calibration against solid standards 2 g of alloy mixed with 15 ml of 50% HNO and boiled to remove NO and cooled; 2 ml of 1% Hg(NO,) solution were then added to prevent interference from chloride and the resulting solution diluted to 100 ml prior to analysis Samples dissolved in H,SO MgSO employed as a chemical modifier Sample decomposed in a quartz reaction vessel using a mixture of HCl HNO H,SO and H,PO acids Inert sample introduction system employed to prevent high B blanks due to HF attack Indirect method based on the formation and extraction of the Cd(o-phenanthroline),(BF,) complex Study of inter-element effects Micro-hydride generation with 20 p1 of sample and 15 pl of NaBH solution introduced to reaction cup; 8-hydroxyquinoline added to remove interference by nickel and cobalt Bi3+ coprecipitated with iron hydroxide followed by the formation of Cu(NH,),2+; the precipitate was recovered and dissolved in HCl Optimization of continuous hydride system for Bi determination based on S/N ratio described 0.1-1 g of sample dissolved in 10 ml of HNO acid ( l + l ) 5mlof2moldm-3KBraddedand solution then diluted to 50 ml; Bi was extracted with 0.05-0.1 mol dm- dodecylamine in CHCl and back extracted from the organic phase with 1-5 ml of 4.4% ammonia solution and 4.4% seignette salt Sample dissolved in HNO excess of HNO expelled by use HCHO and the interference by iron eliminated by the addition of citric acid- triammonium citrate solution Sample heated with mixture of HCl-H,PO then HNO (HF for tungsten steels) and HClO were added and solution was heated at 245 "C until cessation of fuming then diluted dissolution of solid alloy samples prior to AA analysis is described between 2-pyrilideniminobenzohydroxamic acid and iron in MIBK Specific method for monitoring chromium plating and polishing solutions; validity of the method supported by data from 6 years of testing Comparision of solution and solid sampling for determination of Ga in aluminium alloys. Discussion of matrix effects and the use of graphite powder as a chemical modifier Ga was extracted from acidic solutions (pH 0.5-2.0) into xylene by complexation with potassium xanthantes An on-line flow injection procedure for electrolytic Method based on extraction of complex formed No details given in abstract A1 Carbon steel samples AA;ETA,l B Boron-alloyed steel AE;ICP;L B Titanium metal MS;ICP;L B Steel AA;-;L 9014027 91/1541 9 11C16 19 9112575 911C27499 911131 B Iron and cobalt alloys AE;ICP;L Bi Steel- and nickel-based alloys AA;Hy;L Bi Copper powder AA;Hy;L 911137 Bi Low-alloy steels Bi Brasses AE;Hy:L AA;ETA,L 9 111078 9113257 Steel AA;F;L 9 112994 Ca c o Iron and steel AA;F;L 9111 117 AA;-;L AA;FL AA;F;L AA;ETA;S c u Alloy samples 9 112 142 Fe High tensile brass 9 1/708 Fe Chromium plating solutions 9113375 9 1/86 Ga Aluminium alloys Aluminium alloys AE;ICP;L 9113030 Ga Copper-manganese- Ferrosiliconzirconium nickel alloys AE;spark;S 9 1 I894 911320 9 11C 1 727 Ge Hf Hf AE;ICP;L 0.5 g of sample digested in HNO,-HF-H,SO acid mixture and diluted in HC1 prior to analysis 0.5 g of sample spiked with 179Hf and dissolved in HF-H,SO,.The isotopically altered Hf was separated from the matrix by cation-exchange chromatography the solution evaporated out of pure spectral carbon which was then homogenized and pressed into electrodes solutions were employed for calibration Sample dissolved using HF-HNO,. Matrix matched Zirconium metal IDMSspark source;S In Nickel alloy AA;ETA;L 911950JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL. 6 285R Table 1 SUMMARY OF THE ANALYSES OF METALS-co Technique; atomization; analyte form* AA;ETA,L Element Matrix In Tin alloys Ir Platinum metal K Potassium molybdenum bronze Mn Manganese high-alloy steel P Tungsten metal Pb Aluminium alloys Pb Nickel-based alloys Pb Nickel-based alloys Pb Copper metal Pb Steel Pd Titanium alloys S Steel Si Aluminium-silicon and aluminium-silicon-copper alloys Sn Lead-tin solder leachate Te Cast iron Tl Nickel-based alloys V Steel W Cobalt-titanium intermetallic compound Various (1 0) Platinum and palladium metal AA;F;L EDXRF;-;S AA,F;L AE;ICP;L AA;ETA;S AA,ETA,S AFETA,S PAA,-;S AA;ETA;L AA,F;L 1DMS;thermal ionization$ XRF-iS AA;ETA;L M,ETA,L AF;ETA;S AA;F;L AE;ICP;L AA;ETA;L lntinued Sample treatmentlcomments Tantalum lined graphite tube was used 8-fold improvement in sensitivity over pyrolytic coated tube claimed and improved tolerence to interference effects also reported Ir separated from the matrix by liquid chelating exchanger (RCHOCH,CH,) (R =C,H,,) Identification of K compounds in predominant phases of samples prepared by solid state reactions Matrix matched standards required to avoid interferences due to iron 0.4 g of sample was dissolved in 40% HF-concentrated HNO,. The solution was evaporated and the residue boiled in 2.5 mol dm-3 NaOH.To the solution were added 0.5 mol dm-3 H,BO 4 mol dm-3 acetic acid to mask the tungsten and 5 mol dm-3 HNO followed by treatment with ammonium vanadate and molybdate and the resulting phosphovanadomolybdate complex was extracted on a micro-column using a diol sorbent and eluted with solution (0.7-1 mol dm-9 KOH Graphite cup furnace employed for the direct analysis of solid samples.Standard reference alloys were used as both solid and solution calibration standards Direct analysis of solid samples calibration was achieved by the method of additions using Pb(NO,) standard solution Analysis of single-alloy chips (0.5-2.0 mg) RSD in the range 7-20% reported Samples were irradiated with a 23 MeV proton beam for 1-3 h. The sample was etched using 14 mmol dm-3 HNO and dissolved in 6 mol dm-3 HN03. The solution was then passed through Dowex 1- X8 anion exchanger and sample eluted with 0.5 mol dm-3 H,SO,. Pb was determined from the 803.1 and 88 1 .O keV gamma rays of ZwBi steel dissolved in HN0,-HCl; matrix matched standards were employed for calibration Unalloyed steel was dissolved in HNO and alloyed No details given in abstract S determined in four NIST SRMs. Enriched "S was Sample was fused and the melt homogenized by used as an internal standard stirring under a mixture of molten salts (alkali metal and aluminium chlorides and fluorides) and cast into beads (NH,),HPO solution (0.5 ml) 5% Mg(N0)2 solution (0.1 ml) and 10% HNO solution,(0.2 ml).The resulting solution was diluted to 10 ml prior to analysis. Tungstate impregnated tubes were used for the analysis 5 ml aliquot of leachate treated with 10% Ni employed as chemical modifier Analysis of single-alloy chips (0.5-2.0 mg) RSD in the range 7-20% reported Sodium dodecyl sulphate was added to overcome interference effects of several elements Sample was dissolved in a mixture of HN0,-HF and H,S04 was then added and the solution heated until fuming.Tartaric acid was added to prevent hydrolysis of W. Carbon present due to added tartaric acid was employed as an internal standard studied using various types of graphite tubes and a L'vov platform Influence of matrix on analyte atomization was Reference 9112500 911144 9 112 18 1 911958 9111 10 91187 911419 911 1426 9111578 9 I I2580 9111472 9 1 I826 9111 15 9 112438 9 111 468 9 111 426 9112423 9 11 1 608 9014 146286R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 Table 1 SUMMARY OF THE ANALYSES OF METALS-continued Element Matrix Various ( 10) Aluminium alloys Various (6) High-purity aluminium Various (3) Copper metal various (2) Various (30) Various (4) Various (4) Various ( 5 ) Various (8) Various ( 5 ) Various (1 2) Nickel -aluminium alloy Tungsten metal Calcium metal Stainless steel Cast iron High-purity tantalum Molten iron Silicon and aluminium alloys Various ( 5 ) Molybdenum metal Various (4) Silver-based alloys Various (6) Zirconium alloys Various (7) Stainless steel Various (4) Alloy steel Various (4) Copper metal Various (1 9) High-purity chromium Various (9) High-purity mercury Technique; atomization; analyte form* Sample treatmentlcomments AE;ICP;L AA;ETA;Sl AA;ETA,L AE;ICPL AE;ICPL AA;F;L XRF;-;S AE;ICP;L AE;ICP;L AE;-;L AE;ICP;L AE;Hy;L AA;FL AE;ICP;L MS;ICP;L AE;ICPL AE;ICP;Hy AE;ICPL ZAA;ETA;L Analytes preconcentrated with chelating ion exchanger for Cd Co Cr Cu Fe Mg Mn Ni Ti and Zn determined in alloys by spark ablation of samples and dispersion in water before introduction into the graphite furnace 0.10- 1 .O g of sample was dissolved in 20 ml of HNO (1 + 1).The pH of the sample was adjusted to 1-2 with NH,OH; Bi Sb and Sn were coprecipitated with MnO by addition ofi(Mn0 and MnZ+ and was dissolved in a mixture of HNO,-H,O and diluted to 50 ml Alloy fused with Na202 and the cooled melt dissolved in 5% HCl A study of spectral interferences in the determination of 30 elements in a tungsten matrix reported The sample was dissolved in HC1 and the analyte elements extracted with sodium dieth y ldithiocarbamate-CHC13 (internal standard) and 8 ml of aqua regia. A 0.25 ml portion of the digest was applied to filter paper which was then dried Three correction methods for the elimination of interference by the iron matrix were employed and the relative merits of each approach compared removed using an anion exchanger analysis of molten iron NaOH and a few drops of H,O,. On cooling the solution was treated with 10 ml of H,O followed by 20 ml of HC1 (1 + l) boiled with several drops of H,02 cooled and diluted to 10 ml with 5% HCl.Finally the solution was diluted 5-fold with 5% HCl Hydride forming elements in higher oxidation states were separated from the matrix by coprecipitation with lanthanum hydroxide. Optimization of analytical conditions and control of interferences were also discussed Sample treated with dilute HCl to separate the matrix by precipitation Zr matrix removed as ZrCl by chlorination using HCl at 330 "C. The residue was dissolved using a mixture of 3 ml of 6 mol dm-3 HCl-0.5 ml of concentrated HN03-0.2 ml of concentrate H,SO Extended range calibration employed for analysis of varying composition.Interferences due to common background polyatomic ions are also discussed Spectral interference of alloying elements on analyte elements was studied Mathematical experimetal design techniques employed for selecting optimum and compromise conditions for generation of As Sb Bi and Sn h ydrides oxidized with HClO or alkaline H202; trace elements were then precipitated and collected on cellulose loaded with indium hydroxide or on cellulose-H yphan Mercury sample vacuum distilled in a silica boat and the residue dissolved in 3 mol dm-3 of HC1 and diluted to 5 ml with H,O Trace elements (Cu Fe Mg Mn Pb and Zn) 0.1 g of sample was heated with 1 ml of ZnC1 I Sample dissolved in a mixture of HN0,-HF matrix Q-switched pulse laser excitation employed for direct 0.25 g of sample was dissolved in 10 ml of 20% Chromium powder was dissolved in HCl and Reference 91116 91145 91184 911129 911184 911375 911427 911982 9111 172 9111 173 9 111479 9 11 1486 9111522 91/1610 9 1 IC 1 732 91/22 18 9112250 9 1 I2464 9 112495JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 287R Table 1 SUMMARY OF THE ANALYSES OF METALS-continued Technique; atomization; Element Matrix analyte form* Various Non-ferrous metals 9 9 . . -- and alloys Various (2 1) W AE;ICPL Various Tool steels AE;ICP;L Various (5) High-purity copper MS;ICPL Sample treatmentlcomments Review with 15 references on trace element analysis of non-ferrous metals and alloys by AAS and ICP- OES Study of spectral line interferences in the determination of trace elements in tungsten metal Closed vessel microwave dissolution for tool steels was studied and its dissolution speed and reliability compared with those of hot-plate dissolution 1 g of sample dissolved in 8 ml of 7 mol dm-3 HNO 10 mg of La solution were added and the resulting solution adjusted to pH 9-10 by addition of 0.3 mol dm-3 NH,.The solution was filtered and the precipitate dissolved in hot HCl and diluted to 20 ml before analysis by ICP-MS *Hy indicates hydride generation and S L G and S1 signify solid liquid gaseous or slurry sample introduction. Other abbreviations are listed elsewhere. Reference 91/3148 9 1/3192 91/3429 90/4 167 dures for the determination of various elements in steel samples at the low- to sub-ppm level have been reported (9 l/C2804).Polyatomic ion interferences caused by the iron matrix were discussed and detection limits given. Determination of trace elements in three different types of stainless steel by ICP-MS were presented. The extended dynamic range of the technique (20 ng 1-'-20 mg 1-l) was demonstrated and interference by common polyatomic ions discussed (91lC1732). Major and minor elemental constitu- ents were determined in steels following sample dissolution in HCl-HN03 which was evaporated to dryness and the residue dissolved in HN03 prior to analysis. Adoption of this sample preparation procedure was claimed to reduce polyatomic ion interferences.Memory effects due to the iron matrix have also been studied (91K1643). The interference of polyatomic ions as a function of acid dissolution procedure has been investigated (9 11C1723). The effect of polyatomic ions containing F on ICP-MS spectra resulting from the dissolution of alloy steels by HF was reported. The ability to analyse metal samples directly continues to be of great interest and research to achieve this aim is being pursued in most areas of atomic spectrometry. A simple and rapid method for the determination of trace elements in steels based on ETAAS employing a spark ablation for sampling has been described (91/45). The procedure in- volved spark induced ablation of metal samples and dispersion of the material in water prior to introduction into the furnace.Stabilized temperature platform furnace conditions were employed and simple aqueous standards were used for calibration. The direct analysis of molten iron by laser emission spectrometry has been evaluated (91/1173). In this study C Mn P S and Si were determined by employing Q-switched pulsed laser excita- tion at 1.06 pm. Analyte emission was measured following the intense continuum emitted after initial irradiation of the sample. The analysis was not affected by fluctuations of the surface level tilt angle or temperature of the molten iron. The molten iron was analysed continuously at a skimmer of the blast furnace. A review of alternative methods of sample introduction to ICP-OES for metals analyses discussed sampling techniques which avoid disso- lution of the sample prior to analysis (91K2783). Grinding or electrodispersion procedures were employed to provide suspensions of metallic particulates which could be directly introduced into the ICP. However such methods were found to be limited by the fact that the particle size must be in the pm range to ensure efficient atomization of the sample.When the metal was used as an electrode in pure water the electrically dispersed particles were in the sub-pm range. Consequently results obtained using this sample preparation technique were found to be more reliable than those produced by grinding. Other procedures suggested for solid sampling involved direct ablation of the metal. Spark sources may be used for this purpose but these do not provide any spatial information.However laser ablation permits a scan of the surface which provides local informa- tion. The influence of laser characteristics on crater shape the amount of material ablated the size of the particles produced and the type of plasma formed above the surface of the material were discussed in this overview (91K2783). Analysis of low-alloy and stainless steels using spark ablation-ICP-OES has been reported (9 1 /46 1 ). Eleven ele- ments in low-alloy steel were determined. Samples were eroded by a controlled spark and the resulting metal aerosol introduced to the ICP. The precision and accuracy of the analysis was investigated by determination of certified standards. In another application this technique was used for the analysis of free-cutting steels (91/2974).The samples were etched using HCl to remove non-conductive inclusions thus rendering the surface sufficiently conduct- ing to support the spark discharge. Results obtained compared favourably with analysis of the same samples after dissolution. A new technique was reported for normalizing laser power fluctuations in laser ablation plasma AES (9 112373). The technique involves measuring light loss caused by scattering of the ablated material as it flows through a specially designed cell. The variation in absorbance was used to correct for variations in the amount of ablated material. This approach was compared with conventional internal standardization employing a matrix element as internal standard. Three excitation sources for AES namely the Ar ICP Ar MIP and He MIP coupled with laser ablation were compared.The over-all performance was reported to be best for the Ar ICP although in some cases the lower background produced by the MIP produced better results. The spectra were collected with a photodiode-based spectrometer designed for simultaneous multichannel de- tection. This allowed acquisition and subsequent back- ground correction of transient signals produced during ablation. The ability of this detection system to deal with288R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL. 6 complex spectra produced from cast iron was discussed. The role of internal standardization in AE analysis using laser-produced micro-plasmas has been studied (9013998). Temperature changes were found to occur in the plasma as a result of the variation in the amount or composition of laser ablated material introduced.Thus an internal stan- dard was employed to compensate for changes in signal intensity due to this temperature variation. Iron-chromium alloy was used as the test material. Results which were independent of the plasma temperature and the ablation characteristics were reported for the major components (Cr and Fe). However for elements with varying vaporization rates such as Cu and Zn it was found necessary to select an appropriate measurement time after the initial laser pulse to ensure complete atomization of the sample in order to produce satisfactory data. The application of a non-uniform magnetic field to stabilize a d.c. arc prior to introduction of a laser ablation sample introduction has been reported (9 1/3058).Limits of detection were improved by factors of 3-6 compared with the unstabilized arc for the analysis of steel samples. The & of glow discharge sources for direct analysis of metals cdntinues to generate great interest. Considerable research effirt is currently being expended to investigate glow dzscharge processes with a view to translating this knowl- edge into improvements in the design of instrumentation and analytical methodology. The performance character- istics of a jet-assisted glow discharge lamp for use in emission spectroscopy have been described (9 1/2845). A conventional Grimm lamp was modified to produce jet- assisted sputtering by drilling jet channels (0.2 and 0.5 mm) in the restrictor and reversing the gas flow through the lamp.Using this system ablation rates were increased up to a factor of 4 compared with conventional lamp designs. The kinetics of sputtering of pure metals and alloys has been investigated (911C1655). The sputtering rate of pure metals and alloys and pressed powders were calculated and the specimens examined by electron microscopy. The sputtering kinetics were shown to be dependent not only on the sample composition but also on the type of microstruc- ture exhibited by the sample. The effect of a supplementary microwave discharge on excitation conditions in a Grimm discharge has also been investigated (9 11C2789). A dual-cathode glow discharge lamp was used in the sputter modulation mode for the determination of Cr and Mn in steel (9113069). Calibration was achieved by the use of iron-manganese and iron-chromium binary alloy stan- dards and was linear to 3.36Oh for Cr and 2.14Oh for Mn. Results obtained showed good agreement for certified reference standards.A novel hollow cathode glow discharge system employing laser ablation sampling has been de- scribed (9013973). A Q-switched Nd:YAG laser was used to ablate sample material which was introduced into the discharge by means of an Ar gas flow. A photodiode array detector was used to acquire spectral data and spectral intensity profiles of atomic lines in the cathode bore. Optimization of operating parameters such as lamp fill pressure flow rate of Ar gas and discharge current was studied. Laser ablation has also been investigated as a means of sample introduction of metals for ICP-MS.The possibility of using this technique for the determination of elements in steel from ppm to percent. levels using a single analytical method was investigated (911C1642). The accuracy of the method was determined using a variety of steel reference standards. A review of laser ablation ICP-OES as a means of analysing solid samples for a variety of metals and alloys has been published (9 113404). X-ray fluorescence spectrometry remains a widely em- ployed technique within the iron and steel industry and developments in instrumentation and methodology con- tinue to be reported. A field-portable microprocessor- controlled X-ray analyser for rapid alloy identification has been described (9 113496).The radioisotope analyser em- ployed modified Lucus-Tooth-Price intensity corrections for quantitative multi-element analysis. The performance of the instrument was demonstrated for the determination of S in carbon steels and Ni and Ti in stainless steels. An on- line XRF spectrometer for the determination of Ni and Zn in plating bath solutions employed in the electroplating of sheet steel for the car industry has been reported (9 1/3496). The analyser consists of an energy-dispersive XRF spectro- meter and an associated liquid sampling system. Plating process solution was continuously supplied to the spectro- meter. The analyser employed an energy discrimination method utilizing filters. The instrument was reported to have carried out fully automated analyses with good performance over a 9 year period. The use of XRF spectrometry as control analysis in the melting of alloy steels has also been outlined (911428).1.2. Non-ferrous Metals and Alloys As in previous reviews the bulk of the abstracts received concerned the analysis of aluminium and copper metals and alloys. However an increase in the number of abstracts relating to the determination of nickel-based alloys pure transition metals and precious metals was noted. A review on the trace element analysis of non-ferrous metals and alloys by AAS and ICP-OES has been published (9 113 148). The direct determination of Pb in solid aluminium alloy samples by ETAAS has been reported (91/87). Certified aluminium alloys were employed as solid standards. Sam- ple and standards were introduced into a pyrolytic graphite coated graphite cup atomizer.Relative standard deviation values obtained for standards were of the order of 5-6Oh and limits of detection based on 100 mg sample sizes were in the pg g-l range. The same workers reported the use of this system for the direct determination of Ga in aluminium alloys. The use of graphite powder as a chemical modifier was discussed (9 1/86). Inductively coupled plasma OES was also employed for the determination of Ga in aluminium alloys after solvent extraction of the analyte with potas- sium xanthates. Results produced were in good agreement with reference values (9 113030). A method for preconcen- tration of trace elements from aluminium alloys prior to determination by ICP-OES has been described.A chelating ion-exchange resin was employed to separate the elements of interest from the aluminium matrix. Recoveries were 100% for most of the elements studied and the accuracy of the method was determined by reference to ALCAN and NIST reference materials. The preconcentration method can be run in both batch or flow injection mode (91116). In another application B was determined in aluminium by ICP-OES after autoclave dissolution of the sample with hydrochloric acid (9 113259). Other applications of ICP- OES reported included the determination of trace REEs in Si-A1 alloys (91/1479) Ni and Ru in Ni-A1 powders (9 1 / 1 129) and the quantification of main components in A1 bronzes (9111484). In a study of the eflect of sample surface integrity on XRF analysis of A1 alloys 11 surface preparation techniques were evaluated. The technique that caused the most damage and lowest surface integrity was high speed lathe turning under dry conditions.Diamond ultra-turning and diamond micro-milling under lubricated conditions caused the least damage. The effective thickness of the specimen layer necessary to measure analyte-line radiation was shown to be dependent on the analyte atomic number and ranged from a few to several hundred micrometres (9 1/50). Other XRF applications included the determination of Si in Si-A1JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL. 6 289R alloys (91/1156) and the detection of Cr and Mn in aluminium wires and sheets (91/3 139). The production and certification of reference standard material for the analysis of aluminium has been documented (9 1/1288).The analysis of copper and its alloys continues to generate applications for atomic spectrometric techniques. A series of papers concerning the determination of trace elements in a high-purity copper cathode Cu-Cath-1 has been published by the British Standards Institute. Part 1 (91/3112) consi- dered the sample preparation and subsequent AAS determi- nation of Cr Co Fe Ni and Zn. Part 2 (9 1/3 1 12) outlined methods for the determination of Cr Co Fe Ni and Zn by discrete volume-nebulization AAS. In another application FI methodology was applied to the determination of Se in copper metal by hydride generation AAS. Aflow injection manifold incorporating a mini-cation exchange resin was employed for continuous matrix isolation to ensure removal of interfering elements prior to analysis.The developed system was claimed to allow the routine determination of Se at ppb concentrations in the presence of copper matrix levels of 1000 ppm. Inductively coupled plasma MS has also been applied to the analysis of copper metal and alloys. The technique was applied to the analysis of high-purity copper (911C2066). In this method the matrix was removed by electrodeposition onto a Pt cathode. This pre-treatment reduced the level of copper in the sample to below 10 ppm. The electrode potential was set to the point where only Au Ag Bi Cu Hg and Pt were electroplated on the cathode. Losses of analyte elements from the solution other than those mentioned above were reported to be negligible.In order to improve precision and accuracy isotope dilution calibration was employed with spiked isotopes added prior to the separa- tions. The optimized separation procedure and limits of detection obtained together with results for the analysis of NIST reference materials were reported. The determination of trace amounts of As Bi Pb Sb and Sn in high-purity copper by ICP-MS has also been investigated (90/4167). The analyte elements of interest were coprecipitated with La and the precipitate was then dissolved in hot nitric acid and diluted prior to analysis. The remaining applications for copper and copper alloy analyses are documented in Table 1. A number of applications were described in connection with the analysis of precious metals and associated alloys.A comprehensive review discussing the development of selec- tive extractives for precious metals and their application in analytical chemistry has been published (90/400 1). The selectivity efficiency and mechanism of extraction and re- extraction were considered with respect to the effects of substituents attached to the metal binding groups. Enrich- ment of trace amounts of Au Ag Pd and Pt metals by a precipitate floatation has also been described (90/40 1 5). A number of abstracts were received which were devoted to the analysis of silver metal. A direct method for the determination of Au Pd and Pt in fine silver using ETAAS with solid sampling was evaluated (9 K2007). Two methods of solid sampling were considered.The first method involved in situ dissolution of a solid sample by addition of 25% nitric acid in a cup-in-tube atomizer. A high gas flow was required to remove matrix components from the furnace volume during the atomization stage. The second method involved dissolution of the silver sample in nitric acid and agitation of the solution to suspend undissolved elements present in particulate form. In each case calibration was achieved using aqueous standards containing a matching amount of dissolved silver. Results for both procedures were compared with a third method in which the analyte elements in question were extracted from the matrix prior to analysis. A method for the determina- tion of 28 impurity elements in high-purity silver by AES was also described (91/3336).Finally other applications which may be of interest included the determination of trace metals in gold by laser ablation ICP-MS (9 1/C1630) the separation and determi- nation by AAS of trace elements in high-purity platinum and palladium materials (9 1/455) a separation method for trace elements from high-purity rhodium and iridium (9 1/459) and the determination of metallic impurities in platinum and palladium by ETAAS (90/4 146). 2. CHEMICALS This part of the review covers industrial applications of atomic spectrometry to the analysis of a wide variety of materials loosely referred to as ‘chemicals’. Some natural products such as petroleum are included where there is clear synergy with the products produced. The structure of the review is therefore generally similar to that of previous years (see J.Anal. At. Spectrom. 1990 5 323R). One notable exception is that catalysts are now covered in section 3 (Advanced Materials) in view of the similarity of analytical techniques with those used for characterization of refractories (often used as catalyst supports). A summary of publications over the review period relating to analysis of chemicals is given in Table 2. 2.1. Petroleum and Petroleum Products A summary of papers received during the review period which dealt with applications of atomic spectrometry within the petroleum industry is given in Table 2. A general review (472 references) of methods for determination of trace metals in petroleum and related products has been pub- lished by Kaegler (9 1 /345 1 ).2.1.1. Crude oil and fractions The distribution of biomarkers (sterane and triterpane) and sulphur heterocycles (dibenzothiophenes) as determined for example by GC-MS has traditionally been used to characterize crude oils for exploratory and environmental purposes. However it is increasingly being realized that valuable information may also be contained within the trace element constituents of the oil. Price et al. (91lC1645) have shown that trace elements determined using ICP-MS provided a fingerprint which could clearly distinguish between eight North Sea crudes even though the fields were geologically very similar. Changes to the fingerprint during initial stages of weathering were also studied. In a separate study concentration ratios of V:Ni V:Cu Ni:Cu and some composite indices determined using XRF were found to offer good geochemical markers for Miocene and Lower Cretaceous crude oils (9 1/1387). Further information can be obtained if the chemical form of the trace elements in the crude oil can be determined.Zaki et al. (91/21) have used AAS to determine trace elements in heavy distillates and crude oil after extraction with DMF to establish the porphyrin (extract) and nonporphyrin (residue) fractions. A290R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL. 6 Table 2 SUMMARY OF ANALYSES OF CHEMICALS Technique; atomization; analyte form* Sample treatmentlcomments Reference 911373 Element Matrix PETROLEUM AND PETROLEUM PRODUCTS- A1 Lubricating oil AA;ETA;L Sample (5-10 g) ashed in nickel crucible and then fused with 1.5 g of NaOH and 0.5 g of Na,O at 380 "C for 10-1 5 min. Cooled melt dissolved and diluted to 25 ml with 5% HNO,.(Recovery 94- 1 12%) Study of effects of heating rate and maximum temperature on redistribution of As Hg and Se between shale oil retort water and offgas of a 6 kg bench scale retort Application of fundamental parameter software to on- line XRF analysis Flow injection AAS analysis of emulsions of lubricating oils Study of effect of viscosity index (VI) improvers [styrene-isoprene styrene-butadiene poly(alkylmethacry1ate) and ethylene-propylene] on Ca response methods for determination of C1 in crankcase oils hydraulic and metalworking oils fuel oils and oil fuel blends with used oils determination of Fe in complex organic mixtures using FAAS and ETAAS.Use of ETAAS after dilution in IBMK is recommended approach Samples diluted with xylene and analysed using ETAAS. (Concentration range 0.000 18-0.0023% m m As for As Interlaboratory comparison of XRF with chemical Comparison of sample treatment procedures for Quantification of Hg in various hydrocarbon mixtures using ETV-ICP-MS. Decreased recovery reported when at least 14 carbon atoms present in the compound FI into petroleum spirit followed by aspiration into a flame photometer. (Concentrations up to 20 ppm) Common gasoline additive (methylcyclopentadieny1)manganese tricarbonyl is determined down to 0.6 ppm using GC with flame photometric detection porcelain crucible until sulphopolymer obtained. Latter is then calcined at 850 "C for 7 min prior to analysis.(LOD 0.01% m/m) Samples diluted with solvent and analysed using ETAAS. Calibrated using standard additions As for Br Determination of alkyllead compounds in environmental samples using ICP-MS Gasoline and water emulsified using surfactant (Tween 60) and introduced directly to flame using ultrasonic nebulizer Petroleum product mixed with H,SO (1 + 1) in Direct analysis using FAAS with no fuel gas Fuel oil (0.8-1 g) and 4-fold by mass paraffin (m.p. 60-62°C) melted thoroughly mixed and moulded onto a disc for analysis using WDXRF. (Concentration range 20 ppm to 4% mlm) SEM with energy dispersive X-ray (EDX) analysis used to study the influence of elemental S and thiols on the corrosion of Cu strips in ASTM D- 130 test British Standard (BSI) for determination of S in petroleum products using ED-XRF with 55Fe source.(Concentration range 0.0 1-5 % mlm) 9 11C 1807 9113452 As Shale oil retort samples AEMIP,G XRF NAA;L S 911124 XRF-iL AA;FL AA;F;L 911143 9112590 9113575 Br Gasoline Ca Lubricating oils Ca Lubricating oils c1 Used oil and fuel oil XRF-;L 911351 1 Fe Petroleum and products AA;F or ETA,L 9 1/3 135 Fe Petroleum and products AA;ETA;L 9113545 911124 9 11296 1 Hg Shale oil retort samples AE;MIP;G AA;F;G Crude oil and naphtha MS;ICPL XRF NAA;L,S K Gasoline and lubricating oils AE;FL Mn Gasoline additives AE;FL 91/1500 9112458 N Petroleum products AE;-;S 9 111 292 Ni Petroleum products AA;ETA,L 911C565 XRF;-;L M S; I CP; L 91J143 911C557 Pb Pb Gasoline Alkyllead Gasoline AA;FL 9 1 I3468 Pb Pb S Gasoline Fuel oil AA;F;L XRF;-;S 9113558 9 1 /426 Copper Hydrocarbons SEM-EDX;S XRF-;LJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL.6 291R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Matrix Se Shale oil retort samples Si Lubricating oil V Petroleum coke V Petroleum products V Petroleum coke Zn Lubricating oils Various ( 5 ) Crude oil distillates Various Lubricating oil (additive elements) Various ( 15) Lubricating oil Various (7) Petroleum products Technique; atomization; analyte form* AE;MIP;G AA;ETA;L XRF NAA;L S XRF-$5 AA;ETA;L AA; ETA L XRF-;S AA;F;L AA;F;L XRF-;L XRF-;L AE;MIP;G Various (4) Lubricating oils AA;FL Various (1 3) Lubricating oils and additives AE;ICP;L Various Crude oil and heavy residues AA;FL AA ETA; L Various (7) Crude oil XRF-;L Various Crude oil MS;ICP;L Various (8) Oil products AE;ICP;L Various Various (wear metals) Various (wear metals) Various Various Crude oil and naphtha Lubricating and hydraulic oils Lubricating oils Hydrocracker feed Oils AE;MIP;G AE;MIP;L AE;arc;L AF1CP;L AE or MS;ICP;L ORGANIC CHEMICALS AND SOLVENTS- As Organic arsonium cations AA;F;G Sample treatmentlcomments As for As Oil diluted with IBMK and analysed directly using Radioisotope XRF analysis without standards As for Ni Acid extraction of V from petroleum coke samples using microwave heating for 15 min.XRF analysis of extracted solids confirmed total extraction of V from samples ETAAS. (Recovery 92-106%) As for Ca Determination of distribution of Cu Fe Na Ni and V between various fractions of heavy distillates using direct mineralization dilution with organic solvent and solvent extraction (DMF) line XRF analysis Application of fundamental parameter software to on- Sample ( 5 g) of ultrasonically homogenized oil placed in 40 mm diameter cup with 2.5 pm Mylar window.Measured using Philips PW 1480 with He atmosphere and Rh side window tube. (Limits of detection 0.2-3.3 ppm) products. LODs for C S 'H 2H C1 N and 0 are 1 2 4 4 40 50 and 120 pg s- * respectively. Dynamic ranges are > 5 x lo3 Dry ashing in the presence of a porous inert material (silica gel) to reduce loss of analyte by volatilization or sputtering. Tested for Cr Fe Mg and Pb but not appropriate for the last element Samples ashed and then digested with HN03 and HZO2. RSDs were 2.2-12.8% for additives and 3.9-8.1% and 2.5-12.0% for fresh and used lubricating oils respectively Review on determination of metals in crude oil and heavy residues using FAAS and ETAAS XRF used to determine Ca Cr Cu Fe Mg Ni and V in 10 Middle Eastern crude oils.Element ratios and indices shown to provide good geochemical markers. (Concentrations 0.2-36 ppm) North Sea crudes diluted with solvent and analysed using ICP-MS. Measured metal concentration fingerprints allowed clear discrimination of the eight crudes studied against aqueous standards using ICP-OES. LODs for Al Cr Cu Fe Mg Ni Pb and S ranged from 0.003 to 0.1 ppm Advanced data processing algorithm for interference correction in GC-AES analyses. Applicable down to ppb levels Sample introduction system consisted of an ultrasonic nebulizer heated spray chamber condenser and H2S0 absorption cell Electrode configuration and sample delivery modified to improve efficiency of wear particle detection in lubricants Comparison of results obtained by direct analysis in organic solution with those after mineralization New high pressure hydraulic nebulization system permitting direct analysis of undiluted oils Multi-element GC-AES analysis of petroleum Oil samples formed into emulsions and analysed Determination of arsenobetaine arsenocholine and tetramethylarsonium cations by HPLC-FAAS using thermochemical hydride generation.(LODs 13.3 14.5 and 7.6 ng respectively) Reference 911124 911373 911333 91lC565 9 1 I907 9113575 91121 911143 9 11223 911473 911828 91/963 9111 126 9111387 IC 1645 IC 1749 lC1884 9 1 x 2 15 1 9112573 9 1 lC2767 91lC2786 9 llC2805 911157292R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Matrix Cd Organic acid solutions (Cd) Chlorodiazepoxide C1 (Ag) Organosilicon compounds c o Organic chelates 0) Vitamin B,2 (CU) Aliphatic amines (CU) Chlorhexidine 2H GC eluents Mg Organic acid solutions Sn Alkyltin compounds Yb Organic complexes Yb (Sulphosalicylic acid) Technique; atomization; analyte form* Sample treatmentlcomments AA;F;L AE;MIP;G AE;ICP;L AA;ETA;L AA;F;L AA;F;L Zn Organic acid solutions AE;ICP;L Zn Mercaptomethyl- AA,F;L (Zn) Chlorodiazepoxide AA;F;L prop ylproline Zn Pharmaceutical preparations AA;F;L Various Solvents AE;ICP;L Various (14) Cd alkyl compounds AE;-;S Various Volatile solvents AE;ICP;L Various ( 5 ) Solvents Various Solvents Various Solvents Various Emulsified solvents AE;DCP;L MS;ICP;L AE;ICP;L AA;FL AE;ICP;L AA;F;L Study of effects of organic acids on solvent introduction and plasma excitation conditions Indirect FAAS determination of chlorodiazepoxide in pharmaceutical preparations by reduction on Cd or Zn columns.(Concentrations 1-25 pg ml-l) CH30Na-CH30H and Cl preconcentrated by precipitation as AgCl. C1 determined indirectly by measurement of Ag using FAAS. (Concentrations in the ppm range) introduction to FAAS. Complex with trifluoroacetylacetone gave highest sensitivity Indirect determination of vitamin B in pharmaceuticals using FAAS. LOD is 0.2 pg ml-I and RSD (8% at 10 pg ml-1 formation of dithiocarbamate derivatives followed by extraction in chloroform of the Cu" chelates.Cu is measured by FAAS after mineralization AA;FL Organosilicon compounds decomposed with AA;F;G Comparison of chelates for direct vapour-phase AA;FL AA;F;L Indirect determination of aliphatic amines by (HNO3) pharmaceutical preparations using FI-AAS. Sample injected into ammoniacal Cu solution precipitate retained on filter then eluted with HNO Determination of deuterium in GC eluents using atmospheric pressure MIP emission detector with tangential flow torch. (RSD for 2H:1H ratio=2%) Indirect determination of chlorhexidine in As for Cd Several organopalladium complexes tested as chemical modifiers for determination of alkyltin compounds in ethyl acetate-hexane (3 + 2 vlv).20-fold enhancement obtained compounds which can form stable complexes with Yb and their use to depress interferences from other rare earth elements and inorganic acids Sensitivity of Yb increased 23.6 times in presence of sulphosalicylic acid and NaCl and interferences from acids and rare earth elements greatly depressed Sensitivity enhancement effects of organic As for Cd Indirect determination as for Cd Sample (0.5 g) digested with 5 ml HCl evaporated to about 0.5 ml then made up to 10 ml in 10% HC1. Analysed using air-C,H flame at 21 3.9 nm Samples dissolved in mixed solvent containing H20 HCl EtOH and 2-butanone (air-C2H2 flame) Electronic device for control of solvent plasma load using Peltier cooling Samples decomposed to CdO and mixed with NaC1 graphite powder and Floroplast.Some impurities preconcentrated on partially precipitated hydroxide. [LODs 1 x 10-4-3 x lop6% mlm (3 x 10-6-1 x m/m with enrichment] desolvation to improve plasma stability and limits of detection. (LODs ranged from 0.2 pg 1-I for Fe to 5 pg 1-I for Pb) Optimization of FI system. (LODs in ng ml-I B 21; Cu 14; Mo 28; W 120; and Zn 20) Effect of organic solvents on polyatomic ion interferences Comparison of desolvation effects with aqueous and organic sample introduction Study of effect of organic solvents and non-ionic surfactants on profiles of Ca Cr Cu and Fe in C,H2-air flame using dual nebulization system Use of ultrasonic nebulization with cryogenic Reference 9013965 91112 9113417 9117 9 11937 9 11709 9112189 911862 9013965 9113348 911186 9113001 9013965 91112 911377 9113392 9013976 9013991 9013995 9014006 911852 911871 9 1 I942JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 293R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Matrix Various Solvents Various Solvents Various Diethyl ether Various Organic chemicals Various (23) Organic chemicals Various Ethanol Technique; atomization; analyte form* Sample treatmentlcomments AA;F;L AA;F;L MS;ICP;L AE;MIP;G AE or MS;ICP or DCP;L AE;MIPG AE or AFICP;L Various (1 2) IBMK AE;ICPL Various (12) IBMK AE;ICP;L Various Organic compounds AA;FL Various Aqueous-organic mixtures AE;ICP;L Various (6) Alcohol solutions AE;ICP;L Various Organic solutions Various (1 1) Penicillin G Various Organic solutions Various (7) Organic solvents Various (9) Tetramethyltin AE;ICP;L AE;ICP;L AE;ICP;L AE;ICP;L AE;-;S Various Organic solvents and AE;ICP;L volatile compounds Various Pharmaceuticals Various (7) Pharmaceuticals INORGANIC CHEMICALS AND ACIDS- A1 Concentrated salt solutions XRF;-;- AA;-;- AE;ICP;L Mixture of butanol and ethyl acetate proposed as alternative to IBMK for extraction of metal complexes for AAS Ionization suppression for organic solutions by on- line addition of KC1 in aqueous solution using a branched capillary Optimization of plasma conditions for analysis of diethyl ether using ICP-MS and comparison of sample introduction techniques Review of plasma spectrometric detectors for GC and HPLC Review of recent GC-AES applications to petroleum environmental pesticide and aroma samples. Accuracies of 5% or better claimed for quantification using compound independent calibration Study of effect of ethanol addition to aqueous solutions in ICP-OES and ICP-AFS.REE detection limits improved in ICP-OES and tendency to form refactory oxides reduced in ICP- AFS Effect of operating parameters on S/B of analytical lines and excitation temperature for analysis of IBMK in an air-Ar ICP. 50% and 10% air optimum for atomic and ionic lines respectively As above but study of carbon molecular bands. 50% air found optimum for suppression of bands Review of indirect procedures for determination of organic compounds using AAS Effect of cellosolve and ethanol concentrations in aqueous solutions on intensities and backgrounds of ICP-OES lines solutions on S/B of atom and ion lines of Cu Mn Ni Pb Sr and Zn.Increase of outer gas flow can reduce plasma changes conventional Ar plasma for analysis of organic solutions. Suppression of molecular bands at 50% air mixture Direct analysis of sample solutions (1 5% d v ) against matrix matched standards prepared from high- purity penicillin. (ppb limits of detection) thermospray nebulizer from C CN N and NO powder evaporated to dryness and 0.5% NaCl added. Residue treated with 0.5 ml of HCl dried and analysed using AES (Al Ca Cu Fe Mg Mn Pb Te and Zn) Modified direct injection nebulizer for introduction of organic solvents to ICP. Reduced effects of selective volatilization compared with Meinhard nebulizer pharmaceutical analysis various pharmaceuticals using AAS Influence of alcohol concentrations in aqueous Performance of air-Ar ICP compared with Transport efficiency improved (30-40%) using Oxygen added to plasma to reduce band interference Sample (2-6 ml) mixed with 50 mg of graphite Review with 55 references on use of XRF for Determination of Cr Cu Fe Mn Ni Pb and Zn in System for continuous extraction of A1 (complex with cupferron) into xylene phase separation using membrane and analysis of organic phase using ICP-OES.(ppb concentrations) Reference 9 1 /999 91/1463 91/C1646 9 1/C2086 91/C2087 91/C2122 9 l/C2 1 30 9 l/C213 I 9 1/2240 9 1/2408 9 1/C2722 91/C279 1 91/C2840 91/C2876 9 1 /C2907 9 1/C2909 91/3 173 9 1/3282 9 1/3472 91J3473 9 1/C29 13294R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* AA;F;L Sample treatmentkomments Reference 9 1 /927 Indirect determination of NH3 by reduction of Ag ions in the presence of Mn". Unconsumed Ag in solution is measured using AAS. (Concentration range 20-200 jg of NH,) Performance of FAAS using N,O-C2H2 for high salt solutions improved using jaw-type burner with large opening and microsampling technique As extracted with solution containing 2% KI and 0.4% SnC1 in 4-methylpentan-2-one (pH 3-4) then back extracted into 0.4 mol dm- HNO,. Determination using ETAAS with Ta coated device in 8-10% H,-Ar. (0.46-3.35 pg ml-I) PH,-camer gas (H or Ar) mixtures used in manufacture of semiconductor components Sample mixed with concentrated HNO 2.5% La solution and 50 ml of HzO heated to 65 "C aqueous NH added and La(OH) containing coprecipitated As filtered off.Precipitate dissolved in HN03 solution and analysed using ETAAS interference from Ca Na and Sr in DCP-OES and FAAS (N,O-C2H2). (Concentration range 1-500 Pug ml-') 9 111490 9 1 /450 Determination of trace amounts of ASH in 91/1339 9 113053 Mg (5 mg ml-I) added to samples to reduce Preconcentration by crystallization from an aqueous salt eutectic solution. (Detection limit 5 x d m ) Battery sawed opened with tweezers and the contents extracted with HCl-HNO (2+ 1) at room temperature for at least 16 h. (RSD 2.1% LOD 0.0001% d m ) Cd extracted from alkaline aluminium chloride using 6 mol dm-' H3P04-2 mol dmP3 KI and IBMK.Determination using FAAS with air-C,H flame added to mask interference from Fe. (Detection limit 1 ppb) Study of changes in Co K/?/Ka intensity ratios with calcination of CoCO at different temperatures. Large change in ratio possibly due to effect of molecular structure Comparison of results obtained using spectral peak fitting programme with traditional approach Calcium removed from solution by extraction with a mixture of ammonium di(2-ethylhexyl) dithiophosphate (0.5 rnol dm-9 and tributyl phosphate (2 rnol dm-9. Cs determined in aqueous phase after removal of NH,C1 by sublimation 5 ml of 2% APDC added to 10 ml of sample. Cu complex extracted into 10 ml of IBMK and determined using FAAS. (LOD 0.01 pg ml-l) Cu extracted from aqueous solution (pH 4.5) using 5 x 10-3 rnol dm- pivaloyltrifluoroacetonate.(Concentration range 0.0 1-0.0037% m/m) Round robin analysis of N 10-P 34Oh liquid fertilizer. (Concentration range 0.05-O.S0h) Determination of Cu in saline to hypersaline waters containing high Fe concentrations by coprecipitation with FeO(0H). Also applicable for Al Mn and Ni determinations Inteiferences from mineral acids compensated and precision improved using Myers-Tracy internal standardization procedure calibration using standard additions On-line extraction into IBMK using 0.2% APDC. KI 5 ml of 0.5 rnol dm- ammonium citrate solution and Analysis carried out in 2 rnol dm- HCI with As for Cu Element Matrix (45) Ammonia A1 High salt solutions AA;F;L As Phosphoric acid AA;ETA;L As Phosphine AS Copper sulphate electrolytes and electrolytic copper AA;ETA;L Ba Formation water AE;DCP;L AA;F;L 9112775 Caesium iodide Dry batteries XRF-;S 9113027 9014 1 73 Br Cd AA;FL Aluminium chloride Fertilizer Cobalt carbonate AA;FL AA;FL XRF;-;S 9 1/33 I 7 9 113583 90/4 157 Cd Cd c o Cr c s Liquid fertilizer Calcium chloride brines AE;ICP;L AA;FL 9112791 9111366 c u Sodium chloride AA;F;L 9 11948 c u Cobalt oxide AA;F;L 9 11969 9111290 9 112635 c u Liquid fertilizer cu Fe rich brines AA;F;L AA;F;L AE; ICP; L 9 113208 cu Mineral acids AA;F;L AA;FL 9113558 9113538 c u Barium titanate Fe Barium titananteJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 295R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* AA;ETA;L Element Ge Hg Hg I (Hg) Mg Mn Mo P Pb Pb Pb Pb Pd Pt Matrix Mineral acids Sample treatmentlcomments Palladium nitrate added as chemical modifier.For HCl Ge is extracted with toluene and back extracted with tetramethyl ammonium hydroxide. (LOD 0.1 ng g-l) formation of Hg vapour using KMnO and NaBH,. (RSD 4.3% LOD O.OOOl% d m ) Inorganic Hg compounds reduced to vapour using NaBH or Sn". Mercury trapped on gold coated wall of graphite cuvette and then released electrothermally in AAS. (Concentration range As for Cd but determination of Hg carried out after 5- 100 ppb) Indirect determination of I- by measurement of decrease in Hg emision intensity in cold vapour MIP-OES due to interference effect of I- complexes. (Concentration range 2-100 ng ml-1) Study of distribution of magnesium stearate lubricants on the surface of sodium chloride tablets using imaging and static SIMS As for Cu Round robin analysis of N 10-P 34% liquid fertilizer.(Concentration range 0.005-0.1%) A C1,SiH vapour introduction system is described for use with ICP-OES. Calibration for P established using PH On-line preconcentration on PTFE micro-column of Spheron Oxin 1OOO. Column washed with water and analyte eluted with 1 mol dm-3 HNO directly into graphite tube. (Detection limit 0.1 ng ml-I) Preconcentration by electrodeposition on a W electrode (30 s,-0.6 V versus SCE) followed by insertion in graphite cup for ETAAS analysis. (Concentration range 0.4-50 ng ml-I) As for Cu As for Cd Determination of Pd in ammoniacal-Trilon solutions utilized in the electrodeless coating of metals and alloys.(Concentration range 0.01-10 g 1-I) Thermogravimetric and XRD analyses showed H2PtC16 in ETAAS is broken down to volatile PtC12 before being converted into metallic Pt whereas cis-Pt(NH,),Cl is converted into metal in a single step. Could explain why ETAAS response is different for the two compounds As for Cs Sample preparation by membrane coating needs only about one tenth amount of sample compared with conventional pressed tablet. Simultaneous determination of different valancies of S. (Concentration range 0.001-30% d m ) Tandem on-line continuous separation involving reaction with KI to form Sb13 extraction into xylene and then H,Sb vapour generation 5 ml of sample solution treated with 2 ml of H2S04 (1 + 1). Calibration using standard additions Extraction with 0.5 mmol dm- 33- dibromosalicylaldehyde 2- benzothiazoylhydrazone-CHCl solution in the presence of zephiramine at pH 3.8 followed by backextraction into 3.5 mol dm-3 HCl. (Linear up to 300 ng of V) manifold for spectrophotometric determination of Zn.(Concentration range 0.2-60 g 1-I) As for Mo. (Concentration range 0.05-2.0%) As for Cu Application of chemical modification in direct Samples diluted by dialysis prior to injection into FI insertion ICP-OES. Best results obtained using 10 pl spike of 0.25 mol dm-3 NaF to the sample cup Reference 91lC1729 73 14 9 1/90 9 112356 9 113208 9 11 129 1 91/77 90140 12 9 112498 9 112635 9 1/33 17 9 112478 911 1072 Dry batteries M,cold vapour;G 9014 9 112 Mineral acids AA;ETA,G Sea-water and brine AE;MIP;G Sodium chloride tablets SIMS-;S Mineral acids Liquid fertilizer AE;ICPL M,F;L AE;ICPG Trichlorosilane Sodium chloride M,ETA;L Potassium bromide AA;ETA;L Fe rich brines Aluminium chloride Metal coating solutions AA;F;L AA;F;L XRF;-;L H2PtC1 and cis-Pt(NH,),Cl AA;ETA;L Rb S Calcium chloride brines M F L Sulphur sorbents and coal ash XRF-;S 9111366 91/31 77 Sb Zn electrolysis solutions AE;ICP;G 91/C2912 sc V Titanium white sulphate Common salt AE;ICP;L AA;ETA;L 9 11369 91/3479 Zn Hydrometallurgical process streams Spectrophoto- metric;L 911458 Zn Liquid fertilizer Zn Fe rich brines Various Inorganic chemicals M F L M F L AE;ICP;S 9111291 9112635 901395 7296R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* AA;F or ETA,L Element Matrix Various (24) Ammonium perrhenate Sample treatmentlcomments Reference 9014008 Ca K Mg Na and Si determined directly in aqueous solution.Other elements (except Mo) determined after separation of dithiocarbamate complexes. Mo extracted with benzoin oxime Determination of Bi Cu and Zn and Cu Fe and Pb in concentrated sodium chloride and ammonium fluoride solutions respectively ml of HNO (1 + 1) for 2 h in sealed bottle (65-70 "C). Fluorides complexed with boric acid prior to ICP-OES determination of Al Ca Fe Mg Mn Na P Si and Ti 2 g sample treated with H20 decomposed with HCl (1 + 1) and diluted to 100 ml. LODs improved using concentric nebulizer and adding methane as reductant (5- 10 ml min-I) Short pre-oxidation using sodium nitrate prevents losses of S by volatilization and of metals into the platinum crucibles during fusion of mineral sulphides preconcentration of Ag Bi Cd Cu Fe Mo Pb Sb and Zn.Best results obtained with HCl- trioctylmethylammonium chloride-0.002 mol dm-3 APDCIIBMK Changes in state of arc plasma followed with Ba Ca Mg and Mn carbonates as functions of composition of carbon powder mixtures and arc current preconcentrated by matrix removal (5- 10 g) at 180 "C in the presence of 50 mg of powdered graphite. (LODs 3 x 10-*-2 x Review of methods for determining trace impurities in S Se and Te Determination of Ba Ca Fe Mg Ni and Si using axially viewed ICP-OES with direct nebulization using concentric tubular device with bell mouth to prevent clogging.(LODs 0.01 0.003 0.04 0.003 0.2 and 0.5 pg ml-l respectively) tetraborate in ratio 100+97+3 and placed in graphite electrode for spectrographic analysis vacuum distillation over carbon collector in Mo glass ampoules. (LODs 2 x 1O-Io- 6 x lo-* % m/m) Comparison of atomic spectrometric methods for determination of trace elements in saturated brines. (Concentration range 1-50 pg 1-I) On-line preconcentration of trace metals by chelating ion exchange Correction for effects of salt concentration on analyte response by measurement of Sc atom to ion line ratios. Eliminates need for matrix matching of standards Review of determination of trace components of sea- water including trace metals inorganic anions and organic compounds and Pb determined using AAS.Hg determined by ashing at 850-900 "C in 02 trapping Hg vapour in an amalgam and then releasing into AAS by heating. (LODs 0.3-5 pg g-]) Determination of Fe Ni Pb and Zn after electrolytic removal of Cu matrix. (RSDs are 1.8-6.9% in the concentration range 0.0001-0.01%) 90140 10 500 mg digested with 2 ml of HF (50% m/m) and 2 9014 1 62 Comparison of extraction systems for Co Cr Cu Fe Mg Mn Ni Pb and V % d m ) Sample mixed with carbon powder and sodium Preconcentration involving matrix removal by Samples digested with hot HN03-HCl and Cd Cr Various (6) Concentrated salt solutions AA,F;L Various ( 10) Coal AEICPL Various (1 1) Lithium carbonate Various ( 5 ) Sulphides Various (9) High-purity Ni salts AF,ICP;L XRF;-;S AA;F;L 911183 911205 9 11237 Various (4) Carbonates AE;arc;S 911288 Various (9) Ammonium hydrogen fluoride AE;arc;S 911341 Various Chalcogens Various (6) Brine Various AE;ICPL 9 11342 911368 Various (1 3) Sb203 Various (19) Boron bromide Various Brine AE;-$ 911416 9 1 I470 AE;arc;S AE or MS;ICP;L 9 1x745 MS;ICP;L AE;ICP;L 91lC777 9 1lC786 Various Brine Various Sea-water and formation water Various Sea-water Various 9 11949 9111009 Various (4) Fertilizers AA;F or ETA L or G Various (4) Copper oxide AA,F;L 9 11 1477JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL.6 297R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* Element Matrix Sample treatmenthmments De-ionized water added dropwise to weighed sample at low temperature. HNO added and sample heated in microwave oven at low power.HF is then added to complex elements such as Nb Si Ta Ti and W Laser ablation ICP-MS analysis of samples prepared as pressed powders and glass discs. In20 used as internal standard for determination of Ba Fe Mg Mn Sr and Pb dryness and reconstituted in less acidic media. For volatile analytes sample is diluted 10-fold in water. LODs improved using ultrasonic nebulizer ICP-OES analysis of 1-2.5% NaCl solutions using FI Determination of Ag Au Co Cu Fe Pb Pd Pt Sb and Zn in formation waters to provide information on origin and migration history Determination of trace metallic impurities in N2 H HCl NH B,H SiH ASH and PH by flameless AAS For non-volatile elements acid is evaporated to Precision improved and matrix effects reduced in Review of use of XRF in cement plants Review of spectrochemical methods for analysis of high-purity volatile inorganic hydrides halides and organometallic substances Optimization of FI-ICP-OES system.(LODs 0.033-7.6 pg ml-I; RSDs 0.58-2.9%) Determination of Cd Co Cu Fe Mn Ni and Zn in high-purity ammonium and sodium molybdate after extraction into IBMK with 2-(2- benzoxazoly1)cyanoacetaldehyde of mineral acids and some common concomitants during determination of Ca Cd Cu Fe K Li Mg Mn Pb and Zn using ICP-AFS Study of effects of low concentrations ( HCl HNO and HClO.,). Enhancement from HCl suppression from HClO but no significant effect from HN03 composition of mixed carrier ( 5 + 1 AgCl-SrF2). (Detection limits 0.1-50 ppm) Comparison of three techniques (flame with and without preconcentration and ETA) for AAS determination of Cd Cr Cu Ni and Pb in concentrated CaCIJNaCI solutions.ETAAS was best Study of interferences caused by low concentrations A d.c. arc carrier distillation technique with 12% Introduction to use of XRF in fertilizer industry Sample dissolved and Cd Cu Fe Ni and Pb extracted into IBMK using APDC. Al Ca Co Cr Mg and Mn determined in aqueous phase after Zn extracted into CHC1 using trioctylmethylammonium chloride Reference 9 1lC 163 1 9 1 IC 1 637 9 11c 19 12 Various (58) Lithium and lithium hydride AE or MSICPL Various (6) Calcium carbonate Various Mineral acids MS;ICP;S AE;ICPL Various Brine AE;ICP;L :2 128 12555 12624 911 9 9 Various (10) Formation waters AA;ETA;L Various High-purity gases AA;ETA;G Various Cement Various High-purity gases XRF-;S Various 9 112683 9 112689 Various Sodium chloride Various (7) Molybdates AE;ICP;L M F L 9112693 9112704 Various (1 0) Mineral acids AFICPL 9 1 lC2 86 5 Various Acids Various (22) Thorium oxide Various ( 5 ) Concentrated salt solutions AE;ICP;L AE;arc;S M F or ETA,L 9 112980 9113158 9113455 Various Fertilizers Various (1 1) Zinc salts XRF AA;FL 9 113456 9113581 NUCLEAR MATERIAU- B Nuclear materials B Uranium metal or oxide AE;ICP;L AE;arc;S Enhancement of sensitivity of B lines by addition of Sample dissolved in HN03 Mannitol added and He to Ar camer gas in ICP-OES boron separated from matrix by cation exchange.Boron solution evaporated to dryness redissolved in solution containing NaF and Be internal standard and evaporated to dryness on carbon electrode Matrix separation using extraction chromatography with levextrel-TBP resin.Mg(NO,) used as chemical modifier. (Detection limit 1 ppb) 9 1lC548 9 112607 Be U308 M,ETA,L 9112373298R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued El emen t Matrix c o Uranium solutions Ga Plutonium Mn Uranium solutions 23up EfAuent Ru Fuel reprocessing solutions Tc Spent fuel reprocessing streams 99TC Effluent U NaCl leaching solutions Various (1 5) Uranium tetrafluoride Various (7) Uranium oxide Various (70) Radioactive materials Various (7) Process plant d u e n t s Various (30) Uranium compounds various Various Various Various Various Various Low-level radioactive waste Low-level radioactive waste Pu recovery streams Nuclear fuels Nuclear materials Pure As Fe or Ni Technique; atomization; analyte form* AE1CP;L XRF;-;L AE;ICP;L MS;ICP;L M;F;L AEICPL MSICPL AE1CP;L AE1CP;L M,F or ETA,L AE or MS1CP;L MS;ICPL AE;ICPL AEICPL or M,ETA,L AE;ICP;L Mycold vapour,G AE;ICP;L AEarc;S AE1CP;L AA;ETA,L MS;ICP;L or S MS;ICP;L Sample treatmentlcomments Least-squares fitting of pure component spectral curves to spectral regions of solutions containing 10 000 mg 1-1 of uranium. (LOD 0.25 mg 1-I) Ascorbic acid added to 6 mol dm-3 HCl solution of plutonium and Ga separated on anionexchange column.Analyte eluted with 0.02 mol dm-' HC1 and Zn added as internal standard. (Concentration range 0.2-1% m/m) As for Co. (LOD 0.05 mg 1-I) Samples acidified and internal standard solution added Direct determination using FAAS with air-C,H flame.(Concentration range 20-80 pg ml-I). Spectrophotometric methods given for lower concentrations Tc separated from other fission products and heavy metals by precipitation of latter in alkaline medium. (RSDs 2.2% at 9 pg ml-I and 4.9% at 0.9 pg ml-I) scintillation counting adsorption on strongly basic AGlX 8 anion- exchange resin. I and Te also determined using ion chromatography and liquid scintillation respectively NH,OH and HN03 and then passed through TBP modified poly(trifluoroviny1 chloride) stationary- phase column. (Concentration range 0.1-1 pg ml-I) evaporated to dryness and 3 ml of 1 mol dm-3 HN03 and 0.5 g of ascorbic acid added. Solutions passed through column of GDX-301 beads pre- treated with trialkylphosphine oxide.(Determination of Cay Cu Cry Fe K Mg and Mn) separation. Other elements determined using ICP- OES after matrix separation. (Concentration range PPm) Determination of various fission activation and nuclear fuel actinides (e.g. I3Cs lZ9I 9s'c and isotopes of N Th and U) in nuclear plant effluents nuclear waste materials and environmental waters. (LODs 10- 100 ppt) Impurities separated from uranium matrix using tri(2ethylhexyl) phosphate coated columns Removal of U and Th using trioctylphosphine oxide extraction. Determination of Ag As Bay Cd Cry Ni Pb and elements associated with waste treatment using ICP-OES and Hg Se and Tl using AAS Determination of contaminants in process streams of low-level waste water treatment plant.Hg determined using cold vapour AAS Determination of impurities in Pu recovery process streams. Samples prepared using ion-exchange membranes and acid matrix matching Comprehensive methods for determination of trace metals in Tho UO PuO (U,h)O graphite (U,Pu)C (Pu-Al) and (U-Al) alloys Methodologies for analysis of nuclear materials using ICP-MS. Includes application of laser ablation for solid samples and coupled ion chromatography for interference removal and speciation products in samples of pure As Fe and Ni. (Concentration range ppm) As for 23Up. Results compared With liquid Uranyl ions separated from excess of NaCl by Sample converted into U0,(N03) using HzO 0.5 g of sample dissolved in 3 ml of HN03 Actinides determined using ICP-MS with no matrix Determination of total impurities and transmutation Reference 911C541 911454 911C541 9 1 IC 1 647 9 112677 9013952 9 1lC 1647 91J1374 911435 911439 911C542 9 1lC544 911C546 911C547 911C550 9 l/C55 1 9 1 I944 9 1lC 1 632 9 1lC 1648JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 299R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Matrix Various Plutonium Various (4) Environmental samples Various Nuclear fuels (REEs) Various Uranium Various Uranium (REEs) Various (5) Uranium solutions Various Fuel reprocessing liquids AEICPL AEICP;L XRF;-;L XRF;-;L Technique; atomization; analyte form* Sample treatmedcomments Reference MS;ICP;L FI sample introduction (100 pl loop). No matrix 91lC1649 MS;ETA;G 9 1 I2290 separation required Determination of Gd Pu Tc and U using RIMS with three tunable dye lasers pumped by copper vapour laser and time-of-flight mass spectrometer.(Detection limit about 1 x lo7 atoms) Two separation methods used. First based on TBP extraction second involved separation of REEs on alumina column coprecipitation with lanthanum oxalate redissolution and determination using ICP-OES Degradation of detection limits for trace elements in solutions containing high (4%) concentrations of U reduced by Kalman filtering of the spectra obviating the need for chemical separation REEs separated from matrix by adsorption of U on 71 1 anion-exchange resin and further preconcentrated by adsorption on levextrel-PMBP resin. REEs eluted from resin using 1 mol dm-3 HCI. (Limits of detection 0.006-0.07 pg g-I) Direct determination of Dy Er Eu Gd and Sm in uranium solutions using matrix matched standards EDXRF with preliminary selection of energy range of radiation from sample (around Pd Ka line) allows monitoring of Mo Pd Rh Ru and Zr at mg ml-I concentrations AE;ICP;L 9 llC2729 9 llC2885 91/31 30 9113294 9 113401 *Hy indicates hydride generation and S L G and S1 signify solid liquid gaseous or slurry sample introduction respectively.Other abbreviations are listed elsewhere. higher degree of speciation can be achieved through coupling of atomic spectrometry to chromatographic tech- niques. Sullivan (91/C1884) and Firor (91/473) have re- ported application of a commercial GC-MIP-AES system for speciation of trace levels of organometallic compounds in crude oil and non-metallic impurities in naphtha and other petroleum products. The potential benefits of obtain- ing information on the chemical form of elements in petroleum and products particularly at trace levels are clearly very high and so it seems certain that many more applications will be reported in future years as instruments of this type become more widely utilized.Crude oils and naphthas can contain hazardous concen- trations of Hg capable of causing embrittlement of alumi- nium piping and heat-exchange equipment. Electrothermal vaporization ICP-MS has been used to determine soluble and suspended mercurials in petroleum with a limit of detection of around 3 ppb (ng g-*) (91/2961). However decreased recoveries were obtained with compounds containing a larger number of carbon atoms (e.g.14 or more) and so calibration using standard additions was recommended. Similarly the corrosive properties of naphthas are gener- ally governed by their content of S compounds. This is routinely tested by studying the tarnishing of copper strips placed in a naphtha sample for a prescribed time under controlled conditions (ASTM D-130). Scanning electron microscopy with energy dispersive X-ray detection of S has been used to provide a more quantitative assessment of the degree of corrosion on the strips than the subjective visual comparison usually employed (91K1807). The degree of corrosion was found to be independent of the hydrocarbon composition but did depend on the concentration and chemical form of the S compounds.For example the corrosion produced by elemental S was 3.7 times higher than the equivalent concentration of S present as ethylmer- captan and for mercaptans with six carbon atoms the corrosive effect followed the order thiophenob hexane- thiobcyclohexanethiol. Determination of metals in crude oil and heavy residues has been reviewed by Lang et al. (91/1126). Release of heavy metals into the environment can be a serious concern during production and processing of some petroleum products. Olsen et al. (91/124) have used a combination of atomic spectrometric techniques for the measurement of As Hg and Se in the product streams of a bench scale inert gas oil shale retort. Zeeman-effect AAS and MIP-OES were used to monitor the off’s stream and XRF NAA and cold vapour AAS were employed to analyse the raw and spent shales retort water and shale oil.Most of the Hg was found to volatilize into the off’s whereas As and Se preferentially redistributed into the shale oil and retort water. Alkyllead compounds have traditionally been used in anti-knock formulations for gasoline. Several standard (e.g. ASTM) atomic spectrometric methods exist for the determi- nation of total Pb in gasoline using XRF or AAS. However techniques using solution nebulization for sample introduc- tion (e.g. AAS) exhibit widely different responses depend- ing on the chemical form of the Pb compounds involved and their relative volatility. This problem is normally overcome by reaction of the alkyllead compounds with halogens (e.g. ICl 12) prior to analysis.Two groups of workers have reported methods for direct determination of Pb in gasoline using FAAS. Yulin et al. (91/3468) formed an emulsion using the surfactant Tween-60 prior to nebuliza- tion using an ultrasonic nebulizer while Lavrinenko et al. (91/3558) used the gasoline itself in place of fuel gas in the AAS flame. It is not clear from the abstracts whether these approaches completely eliminate the problems of selective300R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1991 VOL. 6 volatilization. For environmental samples the extra sensi- tivity afforded by ICP-MS can be particularly useful. Shelton (9 11C557) has discussed the determination of total organic Pb in water soil and organic liquid using this technique. Other gasoline additives containing K and (methylcyclopentadieny1)manganese tricarbonyl have been determined using FI-FAES (9 11 1500) and GC-FPD (9 1/2458) respectively.As mentioned in last year's review there are several advantages to be gained by introducing petroleum and product samples to ICPs as aqueous emulsions rather than by diluting with an organic solvent. Borszeki et al. (9 1 1C 1 749) have adopted this approach for determination of S and heavy metals in oils and oil products using ICP-OES. Calibration was carried out using simple aque- ous standards. Readers may also be interested in a method for the determination of microamounts ( 10-200 ppm) of oil in water using an atomic absorption spectrometer (911434). The oil was extracted with petroleum ether and determined by monitoring the absoption at 256 nm.2.1.2. Lubricating oils This year has seen a marked reduction in the number of papers reporting the direct determination of wear metals in used lubricating oils reflecting the maturity of this type of analysis. However all atomic spectrometric techniques commonly used for these direct determinations suffer from particle size limitations. Saba (9112573) has modified the electrode configuration geometry and sample delivery to improve wear particle detection efficiency in an arc emis- sion spectrometer. Another development which may be of interest is a hydraulic high pressure nebulizer for ICP or AA spectrometry (9 llC2786 9 11C2805). The nebulizer was operated by forcing solution through a special nozzle of 10 20 or 30 pm under a pressure of 100-400 bar (1 0-40 MPa) provided by an HPLC pump. Aerosol was produced by impact of the resulting solution jet with an impact bead.The aerosol production efficiency was found to be very high (60%) giving rise to increased sensitivity and it was possible to nebulize undiluted oils directly. However the small diameter orifices and filters used will probably prohibit application to used oil analysis in view of the likelihood of blockage by particulates in the oil. In order to overcome the particle size limitations some form of sample degradation is normally required. This usually involves ashing of the sample. Barbooti et al. (911828) reported that more rapid dry ashing could be carried out in the presence of a porous inert material (silica gel). The silica gel was found to prevent sputtering and volatilization of the sample but some very volatile elements (e.g.Pb) were still lost during the ashing procedure. A similar approach has been adopted for determination of A1 in lubricating oil using GFAAS (911373). In this case a folded ashless filter-paper with the conical tip removed was placed in the sample (5- 10 g) in a nickel crucible and the oil was gently boiled and inflamed. The crucible was then transferred into a 750 "C muffle furnace cooled and the residue fused with NaOH and Na202. Baohu (911963) has also reported the determination of 13 elements in lubricat- ing oils using ICP-OES after ashing and digesting the samples in HNO and H202. X-ray fluorescence was among the techniques used in an interlaboratory comparison of methods for the determination of C1 in crankcase hydrau- lic metalworking and fuel oils (91135 1 1).The determination of additive elements (e.g. Ca and Zn) in lubricating oils using AAS can suffer from interferences due to the presence of polymers added to oil formulations as viscosity index (VI) improvers. The effect of various concentrations of the VI improvers styrene-isoprene styre- ne-butadiene poly(alkylmethacry1ate) and ethylene-pro- pylene has been studied (9 113575). Direct determination of Ca in lubricating oil by FI-AAS using emulsions has also been reported (9112590). 2.2. Organic Chemicals and Solvents This section of the review covers the analysis of organic chemicals reagents and solvents. Methods involving pre- concentration by extraction into organic solvents are not included in this section since most of the applications reported have been concerned with the analysis of high- purity inorganic compounds.This work is therefore re- ported in section 2.3. A summary of the analysis of organic chemicals and solvents is given in Table 2. 2.2.1. Chemicals As noted in last year's review (see J. Anal. At. Spectrom. l990,5,323R) few of the papers now being published deal solely with the determination of elements in specific organic chemicals reflecting the extensive literature which already exists in this area. Instead most of the work being reported is concerned either with speciation of trace elements or indirect methods for the determination of organic com- pounds using atomic spectrometry. One notable exception is in pharmaceuticals where atomic spectrometry can be used to replace standard visual-colorimetric methods for the determination of heavy metals giving improved accu- racy sensitivity and selectivity (9 11C2876).Application of XRF (9113472) and AAS (9113473) to pharmaceutical analysis has been reviewed. The determination of Zn in pharmaceutical preparations using AAS with a mixed solvent system (9 113392) and multi-element trace analysis of Penicillin G using ICP-OES have also been reported (9 K2876). Another area that has attracted some interest is sensitivity enhancement and matrix eflect suppression in AAS by complexation with organic compounds. Sensitivity en- hancements for Yb in FAAS (911186 91/3001) and Pd in GFAAS (9113348) have been reported.In both cases sensitivity was improved by about a factor of 20. Castillo et al. (9117) have reported a novel approach for improving sensitivity of Co determination in FAAS by the formation of volatile chelates (providing much higher transport efficiency than conventional solution nebulization). The most effective chelate was found to be trifluoroacetylace- tone. Two simple volatilization systems which could be adapted to conventional instrumentation were reported. The use of atomic spectroscopic detection in separation science has been reviewed by Uden (911C2086). These detectors are increasingly being used for speciation of trace elements using both gas and liquid chromatography. For GC helium MIPS and surfatrons have proved to be effective for both metal and non-metal detection with applications including halogen detection in environmental GC dual-element detection involving B and Fe derivatiza- tion for diols GC of organotin and Se and determination of Ni S and V complexes in petroleum products.Wylie (911C2087) has claimed that the MIP-OES response is nearly independent of molecular structure (within 5% or better) offering the possibility of compound independent calibration for quantitation and determination of empirical formulae. However more studies are required with a wider variety of compound types to assess the general validity of this assumption. The use of GC-MIP-OES for element selective determination of deuteriated compounds has been discussed in a recent publication (9 1/862). This can play an important role in determination of the function and structure of organic and biological compounds (e.g.deter- mination of metabolites in body fluids and tissues arising from the use of a deuteriated drug). For HPLC argon ICPsJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 301R or DCPs are generally used with OES or MS detection for applications such as the determination of phosphinates polyphosphates and organomatallic cations. Sensitivity can be enhanced using a direct injection nebulizer which also gives a more uniform response for compounds having widely differing volatility (91/3282). In an alternative approach to improving sensitivity Blais et al. (9 111 57) have used a novel coupled HPLC-AAS system with thermo- chemical hydride generation for determination of arseno- betaine arsenocholine and tetramethylarsonium cations.The methanolic HPLC eluent was nebulized using a thermospray pyrolysed in a methanol-oxygen kinetic flame and the analytes were thermochemically derivatized to hydrides in the presence of excess of hydrogen. The volatile derivatives were then transported to a cool diffusion oxygen-hydrogen flame atomizer for AAS measurement. The absolute limits of detection for arsenobetaine arseno- choline and tetramethylarsonium cations were 1 3.3 14.5 and 7.6 ng respectively. It is perhaps surprising that there have been few reports on the use of plasma spectrometric detectors for supercritical fluid chromatography (SFC) in view of their inherent suitability for this application. However these will undoubtedly feature strongly in future reviews as SFC techniques become more widely accepted.A particularly innovative approach to speciation of trace elements has been described by Caruso and co-workers (91/860). By varying the power of a low-pressure helium MIP within the expansion stage of a VG PlasmaQuad ICP- MS instrument varying degrees of fragmentation of the analyte molecules was achieved. As the power was in- creased changes in the fragmentation pattern occurred eventually resulting in elimination of the parent ion. This approach permitted structural information to be obtained for compounds with mass within the range of the quadru- pole. Several alkanes and aromatic compounds with mass less than 160 were examined. The potential of using nitrogen as the plasma gas to obtain fragmentation was also studied.The indirect determination of organic compounds using AAS was reviewed by Kucova (9 1/2240). Procedures based on extraction of ion pairs formation of chelate complexes precipitation reactions or redox reactions were described. An indirect method for the determination of aliphatic amines was among those reported in the year under review (9 11709). The method was based on formation of dithiocar- bamate derivatives by reaction with carbon disulphide in basic medium followed by extraction in CHC13 of the copper@) dithiocarbamate. Applications of indirect mea- surement in the pharmaceutical field included FI determi- nation of chlorohexidine by precipitation with copper@) (9 112 189) and the determination of chlorodiazepoxide by zinc or cadmium reduction in a continuous system (9 1 / 12).The latter method which is selective towards the N-oxide group has a sampling frequency of 150 per hour. The high selectivity and sensitivity of AAS can allow indirect determination of many compounds in pharmaceutical preparations at ppm concentration levels. The methods are relatively cheap extremely rapid and can be readily automated and so are particularly suitable for quality control type applications. It therefore seems likely that applications in this area will continue to attract attention for some time. 2.2.2. Solvents Most of the papers published within this review period have been concerned with the eflect of organic solvents on ICP sources for OES and/or MS. In some cases the work concentrated on the benefits that can be gained by for example adding organic solvents to aqueous solutions while others were concerned with reducing matrix effects caused by introduction of solvents to the plasma. The influence of organic solvents added to aqueous solutions on ICP-OES spectral lines and background is a complex function of the nature of the solvent mixture composition excitation conditions and presence of matrix elements (9 112408).Most workers have reported increased transport efficiency in the presence of organic solvents possibly due to production of a smaller droplet size distribution. However the effect on plasma temperature and spectral line intensities depends on the nature of the solvent and the plasma operating conditions. Blades et al.(90/3965) found that for organic acids the temperature in the lower region of the central ICP aerosol channel was increased relative to H20 solutions giving rise to higher ion to atom line ratios. Conversely for alcohols Steffan and Vujicic (91/C2722 91/C2791) reported a cooling of the analyte channel of the plasma resulting in an increase in S/B ratios for lines with excitation potential less than 5 eV but a decrease in SIB ratio for lines (atomic and ionic) with higher excitation potential. Irrespective of the mechanism addition of organic solvents to aqueous solutions can be beneficial. For example by adding ethanol to sample solutions and using desolvation detection limits for ICP- OES determination of rare earth elements were improved by an order of magnitude (91K2122).Addition of ethanol to the sample solution can also reduce the tendency of elements to form refractory oxides in the ICP tail plume. This is beneficial when the ICP is used as an atomizer for AFS. Thus a limit of detection of 24 ng ml-l for the determination of Eu in yttrium oxide was obtained. Addition of organic solvents to aqueous solutions can also be beneficial for ICP-MS. Evans and Ebdon (911852) showed that dramatic reductions in polyatomic ion interfer- ences (ArCl Ar2 and C12) were achieved by adding about 10% propan-2-01 in water. However similar benefits were also obtained by adding a small amount (about 0.03 1 min-l) of N2 to the nebulizer gas and so the latter approach was recommended. Most of the work on analysis of organic solvents carried out during the review period has been concerned with the effects of volatile solvents in ICP spectrometry.Ebdon and co-workers (9 1/C778 9 1/C1646) have compared the effects of different interfaces spray chambers and aerosol desolva- tion procedures for introduction of organic solvents to the ICP. One of the most criticial parameters appeared to be desolvation. Plasma excitation temperatures were observed to decrease with increasing solvent vapour loading when controlled with a variable temperature condenser (9 1/87 1). It was suggested that the main impact of desolvation with organic solvents was to reduce the C2 species population in the plasma which in turn strongly influenced plasma temperature and reduced band interferences in ICP-OES. An electronic device based on Peltier cooling was described which was used to control the solvent plasma load in ICP spectrometry (90/3976).The device was found to be more convenient than an aerosol cooling tube immersed in a liquid cooling bath and offered potential for automation of solvent load experiments. Weiderin et al. (90/3995) have clearly demonstrated the benefits which can be gained in ICP-OES by employing aerosol desolvation. A two-step desolvation system was used for continuous ultrasonic nebulization of organic solvents. The aerosol was first heated above the b.p. of the solvent with vapour subse- quently removed in two condensers kept at - 10 and about - 80 "C respectively. Limits of detection were comparable with those obtained by ultrasonic nebulization of aqueous solutions (0.2-5 pg l-l) even for 'difficult' volatile solvents such as methanol acetone acetonitrile or ethanol.Band emission from C2 was found to be about 25 times less302R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 than when the aerosol was partially desolvated using only a condensation temperature of - 10 “C. An alternative approach to reducing band interference in ICP-OES analysis of organic solvents is to oxidize the molecular species (e.g. C,) by addition of oxygen or air to the plasma. Tang et al. (91/C2840 91/C2130 911C2131) have reported that molecular bands due to organic solvents could be greatly depressed (or even eliminated) using a 50% v/v air-argon cooled ICP. Several atomic lines also showed optimum S/B ratios at this concentration of air but ionic lines showed maxima at 10% v/v air at which concentration the CN band emission was very intense.Nevertheless detection limits for 12 analytical lines were lower in a 50% v/v air-argon cooled ICP than in a conventional argon cooled ICP. However in a study involving addition of oxygen to the plasma it was found that CN C2 N2 and NO bands were reduced but not completely eliminated and that background noise was increased (9 1 /C2909). Aerosol desol- vation is therefore probably the preferred approach espe- cially in view of its effect on plasma temperature. Other approaches to the introduction of organic solvents to ICPs which have been reported include use of a thermospray nebulizer (911C2907) and a modified direct injection nebulizer (9 113282).The latter approach is particularly useful for samples which contain volatile analyte species since the system gives a more uniform response to com- pounds having widely different volatilities. A few papers have been published concerning the introduction of organic solvents in FAAS. Bagdi et al. (9 1/942) studied the atomization processes in FAAS analy- sis of oganic liquids while Watling et al. (9 1 / 1463) observed on-line ionization suppression in organic solutions using a non-miscible aqueous suppressant (KCl solution). For any workers who have difficulty obtaining IBMK a 1+1 mixture of butanol and ethyl acetate has been reported to be an acceptable alternative for extraction of metal complexes for subsequent AAS analysis (9 1/999). Miscibility with water can be reduced by adding a small amount of AI(NO3h.23. Inorganic Chemicals and Acids This section of the review covers analysis of inorganic chemicals and acids. However those chemicals generally regarded as exhibiting material functionality are not in- cluded since these are covered in section 3 of the review. The structure of the review this year differs from previous years in that analysis of catalysts is also included in the later section in view of the fact that many catalyst support materials are refractories and that many of the techniques used for characterization of catalyst surfaces are similar to those used for other ‘advanced materials’. Since the boundary between the categories is somewhat arbitrary however readers should also refer to the later section and Table 3 for comprehensive coverage of analysis of ‘inor- ganic chemicals’ and catalysts.2.3.1. Chemicals Analysis of solutions containing high salt concentrations continues to attract considerable attention in view of its importance in several industrial applications. In the chlor- alkali industry trace elements even at very low concentra- tions can cause blockages of the sensitive membranes employed in the electrolytic production of sodium hydrox- ide (9 1/C745) while in the petroleum industry determina- tion of trace elements in sea- and formation waters is important for prediction of scaling problems and to aid reservoir diagenesis studies (91/2555 91/2775,91/2929). A review with 165 references has been published covering the determination of trace components (metals inorganic anions and organics) in sea-water and salts (91/949).Inductively coupled plasma emission spectrometry is an attractive technique for the determination of trace elements in view of its multi-element capability good sensitivity and ease of operation. In solutions containing high levels of dissolved solids however the precision and accuracy of the technique can be severely degraded by salt deposition on the nebulizer orifice and evaporation-atomization-excita- tion effects in the ICP. The former problem can be overcome by using an appropriate nebulizer e.g. Pan et al. (911368) have reported the direct determination of trace elements in brine using an axially viewed ICP-OES instru- ment with a bugle-shaped concentric nebulizer.The latter problem can be more difficult to resolve and matrix matching of standards and samples is the conventional approach. This may not be possible if the sodium content of the samples is not known. Thomsen (911C786) has there- fore adopted a novel approach in which the sodium concentration in the sample was estimated by measuring the Sc atom to ion line ratio and correction factors applied to compensate for the matrix effect. Presumably the same result could be achieved by measuring the sodium concen- tration directly using its emission line. Precision and accuracy of determinations can be improved using FI (91/C2128 9112693) but in order to obtain the best performance some form of matrix separation is generally required. Chelating ion exchange has been shown to be a convenient method for on-line preconcentration of trace metals and matrix removal prior to ICP-OES or ICP-MS analysis (9 1 1C7 77).Determination of trace elements in solutions containing high levels of dissolved solids can also be carried out directly using FAAS with suitable modifications. Gruber et al. (9 1 / 1490) reported the determination of Al (dinitrogen oxide-air-acetylene flame) in salt solutions using a jaw-type burner with a large opening while Bekzharov (9014010) used a dosage device which employed the dosage scheme ‘washing solution-sample-washing solution’ for analysis of 30% NaCl and 30% NH4F solutions. As with ICP-OES however better results are generally achieved if some form of matrix separation is employed. Generally elements of interest were separated from Group I elements (Na) by coprecipitation (9 1/2635) or by extraction into organic solvent using a chelating agent (91/948,9 113479).However the reverse separation can also be utilized. Samoilov et al. (9111366) have developed a method for the determination of Rb and Cs in calcium chloride brines after extraction of Ca into heptane using a mixture of ammonium di(2- ethylhexyl) dithiophosphate and tributyl phosphate. Methods for the determination of Cd Cr Cu Ni and Pb in concentrated calcium chloride1sodium chloride including FAAS with and without preconcentration and ETAAS have been compared (9113455). Electrothermal AAS was found to be most satisfactory although on-line preconcen- tration has also been reported to reduce matrix interfer- ences using this technique (90140 12).This year has seen something of a renaissance in the use of AAS with preconcentration techniques for analysis of high-purity inorganic compounds. At first sight this may seem somewhat surprising in view of the increasingly widespread availability of rapid multi-element techniques with high sensitivity such as ICP-MS. However although the latter technique performs exceptionally well for many elements those below mass 80 can suffer from severe interferences from argon and polyatomic ions necessitating combined use of ICP-MS and ICP-OES to achieve compre- hensive elemental coverage (9 1 /C 163 1). For determination of the lighter elements use of AAS with preconcentration may offer a cheaper and more attractive alternative. The most popular preconcentration technique reported in-JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 303R volved extraction into IBMK using a complexing agent such as APDC and this approach has been applied to the determination of a large number of elements in high-purity nickel (911237) and zinc salts (91/3581) ammonium per- rhenate (9014008) and aluminium chloride (91133 17). Sub- ppm Osg g-l) detection limits were generally achieved using this approach. Other chelating agents which have been used include pivaloyltrifluoroacetonate for the determination of Cu in cobalt oxide (9 1/969) and 2-(2-benzoxazolyl)cyanoa- cetaldehyde for the determination of trace elements in molybdates (9 1 12704). Preconcentration using electrolysis (9112498) and co-precipitation with LL~(OH)~ (9 113053) have also been used for the ETAAS determination of Pb in high-purity potassium bromide and As in copper sulphate electrolytes and electrolytic copper respectively.Precon- centration by extraction into organic solvents can also be used with ICP-OES provided that the solvent employed is not too volatile. Two on-line separation systems utilizing extraction into xylene have been reported for the determi- nation of ultra-trace (ppb) levels of Al in concentrated salt solutions (911C2913) and for the determination of Sb in zinc electrolysis liquids (9 1 /C29 12). The latter method employed a particularly novel tandem separation approach in which the Sb was reacted with KI to form Sb13 which was extracted into xylene and subsequently converted into For the determination of trace element impurities in high-purity solids it is preferable if these can be analysed directly rather than after digestion in order to avoid dilution of the sample and reduce risks of contamination. Atomic emission spectrometry using a d.c.arc is particularly suited to these determinations in view of the simultaneous multielement capabilities of the technique. Sensitivity can be improved using such a system by distilling the matrix from a carrier such as carbon (91/341 911470) or AgCl-SrF on which the impurities are retained and preconcentrated. Using this approach Durinov et al. (911370) were able to obtain limits of detection of 0.01-1 ppb (ng g-l) for the determination of 19 trace elements in high-purity boron bromide.Laser ablation ICP-MS is a relatively new technique for trace element analysis of solid samples which is rapidly gaining popularity. Perkins et al. (911C1637) applied the technique to the determination of Ba Fe Mg Mn Pb and Sr in calcium carbonate. Good calibration graphs were obtained either using added In203 as internal standard or using a minor calcium isotope. The measured Mg/Ca and Sr1Ca ratios from the shells of certain organisms can be used as palaeosalinometers and palaeothermometers. How- ever laser ablation ICP-MS analysis of bivalve shells showed irregular distributions of the minor and trace elements casting doubt on the validity of traditional methods which use a bulk shell digestion approach. A more traditional (if somewhat less quantitative) approach to spatially resolved elemental analysis of solid surfaces is SIMS.Hussain et al. (9112356) used SIMS to study the distribution of magnesium stearate lubricant on the sur- faces of sodium chloride tablets. X-ray fluorescence is undoubtedly one of the most widely utilized techniques for direct bulk analysis of solid samples within industry. However the technique is prone to severe matrix eflects arising from particle size and X-ray absorp- tion effects. This often necessitates that samples are fused into a glass bead prior to analysis. If the sample contains sulphides however problems can occur due to volatiliza- tion of sulphur species and/or attack of the platinum crucibles used to perform the fusion. Norrish and Thomp son (911205) developed a method to overcome these problems involving short pre-oxidation treatment using sodium nitrate prior to fusion.X-ray fluorescence methods have also been reported for the determination of bromides -US SbH3. in caesium iodide (91/3027) and of S in sulphur sorbents and coal ash (9 1/3 177). In addition to its traditional role in determining total element concentrations in samples there is growing evidence that in some cases information can also be obtained regarding the chemical form of the element in the sample. LaBrecque and Rosales (90/4157) used Co WKa! intensity ratios to study the calcination products of cobalt carbonate (9014 I 57). Results were consistent with those obtained using XRD. A review of use of XRF within a cement plant (9112683) may also be of interest.Determination of trace element impurities in high-purity gases is an important requirement within the semiconduc- tor industry. Shishov (9112689) has produced a review (1 33 refs.) on spectrochemical analysis of high-purity volatile inorganic hydrides halides alid organometallic substances in which the limitations of several techniques were com- pared. Specific applications described included the determi- nation of arsine in mixtures of phosphine using AAS (9111339) and the determination of P in trichloro- silane using ICP-OES (91/77). Methods for the determina- tion of trace metal impurities in high-purity N2 H2 HCl NH BzH6 SiH ASH and PH3 using ETAAS have also been established (9 112624). Many of the methods presented are suitable for on-line control. Several papers have been published dealing with elemen- tal analysis of fertizizers using AAS (9 1 / 1009 9 1 / 1 290 91/1291 91/3583) ICP-OES (91/2791) and XRF (9113456).Readers may also be interested in an indirect method for the determination of ammonia using AAS (9 1/927) and a comprehensive review on the determination of trace impurities in chalcogens covering a wide variety of analytical techniques (9 11342). 2.3.2. Acids Unlike previous years this review year has seen very little work published on the determination of trace elements in high-purity acids (but see also section 3.2 for semiconductor reagents). One exception is a report on the use of an ultrasonic nebulizer for the analysis of high-purity acids using ICP-OES (9 1 /C 19 12). It can perhaps be inferred that the techniques available are now adequate for most applica- tions of this type.Readers may also be interested in an ETAAS method for the determination of ppb concentra- tions of Hg in concentrated hydrochloric sulphuric and phosphoric acids (9112714). The method described in- volved reduction of mercury compounds using NaBH or Snn and trapping of the resulting mercury vapour by amalgamation with gold on the wall of a graphite cuvette. The effect of low concentrations (< 1% v/v) of mineral acids on ICP-OES emission intensities has been studied by Mermet and co-workers (91/2980). An increase in signal was observed for HC1 with maximum enhancement at an acid concentration of 0.00 1 % v/v HClO however caused a suppression of the signal. No significant effect was observed for HNO,.In view of the fact that most standards used for calibration of ICP-OES instruments are prepared in dilute acid solutions this work has serious implications which all analysts making use of this technique will have to take into consideration. One possible solution to the problem is to make use of internal standardization. Garden et al. (9113208) have shown that mineral acid interferences can largely be compensated for by utilizing this approach. Significant enhancements from low concentrations of min- eral acids in ICP-AFS have also been reported (91/2865) with the effect being more pronounced when propane was used as reducdant. 2.4. Nuclear Materials Atomic spectroscopic methods play an important role in the nuclear industry for quality assurance at different stages304R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 of nuclear fuel fabrication (9 1/944) and for monitoring low- level radioactive waste water treatment (9 l/C550) and leaching of vitrified radioactive waste (9 1/1374). Generally comprehensive approaches are adopted in which atomic spectrometry plays a key role alongside other techniques such as alphahewgamma activity counting ion chromato- graphy and electrochemistry. Certified reference materials for use in nuclear safeguard applications and in geological and environmental research are distributed by the New Brunswick Laboratory (9 UC1947). Inductively coupled plasma OES forms a major part of most schemes for elemental analysis of nuclear materials. However most of these materials exhibit complex spectra originating from heavy elements such as uranium.The elements of interest therefore generally have to be separated from the matrix. A review with 110 references has been published on the use of ICP-OES for analysis of high-purity substances including nuclear materials (9 112690). This review compared the analytical performance of ICP-OES with and without the aid of preconcentration techniques. The most commonly reported approach for removal of uranium or thorium from solutions was extraction using solvents such as tri(2-ethylhexyl) phosphate (TEHP) (91/C546) TOP0 (9 VC547) or tributyl phosphate (TBP) (9 1/C2729). However these methods are generally not fast enough for process control applications and also can generate large volumes of flammable contaminated sol- vent.Most recent work has therefore concentrated on column based extraction systems. Columns which have been described include TBP-modified poly(trifluoroviny1 chlo- ride) (91/435) TEHP coated acrylic resin (91/C546) and 7 1 1 anion-exchange resin (9 1/3 1 30). Uranium could be stripped from the former column using nitric acid and since the TEHP resists acid degradation it was claimed that the columns can be used indefinitely. For elements present at very low concentrations some form of preconcentration was required in addition to matrix separation. Two ap- proaches have been described for the determination of rare earth elements in uranium and nuclear fuels using precon- centration on levextrel-PMBP resin (9113 130) and concen- tration on an alumina column followed by precipitation with oxalic acid (91K2729).Matrix separation using ion exchange has also been described for at-line analysis of plutonium process streams (9 1/C55 1). For determination of Te in spent fuel reprocessing streams anion exchange was preceded by a rough separation by precipitation (90/3952). Simply changing the pH of the solution to make it alkaline was found to precipitate most of the fission products along with heavy metals but did not affect the Te. Cation- exchange separation has also been used with a.c. arc OES for the determination of B in uranium metal (91/2607). In addition to time and convenience considerations extraction techniques also have the disadvantages that some of the trace elements can be extracted the uranium matrix may not be fully extracted and the separation can cause contamination.Wangen et al. (91K541) and van Veen et al. (91K2885) have reported chemometric ap- proaches for compensation of uranium interference in ICP- OES spectra based on least-squares fitting of spectral regions and Kalman filtering respectively. Encouraging results were reported and in the latter case limits of detection were obtained for 12 elements in a 4% uranium solution which were suitable for ASTM C787 specifications without use of chemical separation. As with ICP-OES determination of trace elements in nuclear materials using AAS usually requires matrix separa- tion. For example Heinig et al. (91/2677) found that although Ru could be determined directly in model repro- cessing solutions using FAAS in the range 20-80 pg ml-l for lower concentrations separation of Ru was required.Matrix separation techniques for both FAAS and ETAAS were similar to those adopted for ICP-OES e.g. extraction chromatography with GDX-30 1 beads treated with trialkyl- phosphine oxide (911439) or levextrel-TBP resin (9 1/2373). When combined with ETAAS ppb limits of detection could be achieved. X-ray fluorescence is an attractive technique for process monitoring in view of the inherent stability and robustness of the technique. Saleem et al. (91/3294) described a simple method for the determination of Dy Er Eu Gd and Sm in uranium solutions using XRF with matrix matched stan- dards. Energy dispersive XRF is a particularly attractive technique for monitoring processes since several elements can be measured simultaneously.However owing to the limited dynamic range of this type of detector intense lines originating from the matrix must be eliminated from the measured spectrum. Gal'tsev et al. (91/3401) described a system which makes use of reflection from a pyrolytic graphite assembly to eliminate unwanted lines from the fluorescence spectrum of nuclear power plant spent fuel reprocessing liquids prior to measurement of Mn Pd Rh Ru and Zr using EDXRF. As with other atomic spectros- copic techniques performance of XRF for analysis of nuclear materials can be improved using matrix separation. A method for the determination of Ga in plutonium using anion exchange and XRF has been reported (91/454).Unlike most other atomic spectroscopic techniques for the analysis of nuclear materials the simple ICP-MS spectra produced by nuclear materials means that for many applications this technique can be used with no matrix separation (9 1/C 1649). This advantage coupled with the extremely high sensitivity of the technique (ppt limits of detection) (91/C544) have resulted in its gaining wide- spread application throughout the nuclear industry. Appli- cations reported during the review period have included measurement of transmutation products in materials for fusion reactors (91K1648) and determination of 99'c and 237Np in effluents (9 l/C1647). Unfortunately isobaric and polyatomic ion interferences particularly below mass 80 often necessitates that a combination of ICP-OES and ICP- MS is used in order to obtain complete elemental coverage (9K542).A possible solution to this problem is use of coupled ion chromatography ICP-MS. Alonso et al. (9 1 /C 1632) have used this approach both for elimination of matrix and isobaric interferences and for speciation studies of transuranium elements in solution (9 1K1632). Although most applications reported so far have utilized conventional nebulization for sample introduction other approaches such as laser ablation for direct analysis of solids (9 1 /C545) and electrothermal vaporization (914343 9 1/C545) are gaining popularity for the analysis of nuclear materials. Another sensitive element and isotope detection system for plutonium and other long-lived radioactive nuclei which has been reported is RIMS (9112290).Detection limits of the order of 1 x lo7 atoms were achieved with a four colour multi-step resonance ionization scheme which nearly matched the target of 1 x lo6 atoms required for environ- mental applications. However since detection limits of 1 x lo6 atoms can be readily achieved with commercial ETV-ICP-MS systems (91/C543) it is difficult to see how the cost and complexity of the RIMS approach can be justified especially in view of the rapid multi-element capability and versatility of ICP-MS. The latter approach will almost certainly find more widespread applications throughout the nuclear industry. 2.5. Process Analysis and Automation X-ray fluorescence is particularly well suited to on-line elemental analysis in view of its stability robustness non-JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 305R destructive nature and ability to operate in harsh industrial environments. Applications of on-line XRF and XRD analysis techniques to industrial process control have been reviewed by Hietala and Kalnicky (911145). On-line XRF has been used in mineral processing applications for about 20 years and continues to find widespread applications in this field for example for on-stream ore slurry analysis (9 111 44). Applications in other industries have been slower to develop but may be boosted by the availability of a new commercial EDXRF process analyser (9 l/C209 1). The analyser is enclosed in a stainless-steel NEMA 4X cabinet which can operate in a Class 1 Division 1 Group C or D area.Sample excitation is accomplished using a water cooled 50 kV 1 mA rhodium anode X-ray tube with detection using a thermoelectrically cooled Si(Li) detector. The unit can accommodate up to eight flowing streams with eight static cells for calibration. The system may be particularly useful for applications within the petroleum industry e.g. determination of S in hydrocarbon streams Pb in gasoline and additive elements in lubricating oils. Leland et al. (91/143) discussed use of fundamental parameters software for calibration of the latter two on-line applications. X-ray fluorescence has also been used for the determination of SO2 in ambient air and in stacks of a tobacco curing plant (9113555). Sulphur dioxide was col- lected on filters impregnated with 5% Na2C03 and 3% glycerol and S was then determined using EDXRF.The limits of detection for S were about 30 pg using a sealed proportional counter system and about 2 pg using a system with a Si(Li) detector. For monitoring liquid process streams ICP-OES is an attractive option in view of its speed multi-element capability and low detection limits for most elements. However in general sample introduction systems used with laboratory based ICP-OES systems are not suited to continuous operation without maintenance which is a requirement in process control applications. Foster and Carroll (9 1/C2027) described a sample introduction system which was specifically designed for on-line analysis. The ICP can be used in conjunction with on-line preconcentra- tion systems if very low concentrations of elements are to be determined.Knapp and co-workers (9 1/ 102) compared two chemically bonded chelating ion-exchange systems which were found to be suitable for automatic-on-line preconcen- tration of trace elements for water analysis. On-line real-time analysis of process gas streams such as gassification and combustion processes is becoming increasingly important. A high-power high-flow mixed gas helium-argon ICP-OES instrument has been described which is suitable for these applications (9 1/466,9 l/C2029). The particulate laden gases were injected directly into the ICP torch at high temperatures (500 "C) and at the high sample flow rates (up to 5 1 min-l) necessary to prevent loss of large particles (1 0-20 ,urn) between the process sampling point and the plasma.Elements of interest including As Ca Cd Fe Pb S and V were continuously monitored to provide real-time process information. Automated analysis of solid samples by AAS and ICP- OES has been the subject of some attention during the review period. Kempeneer et al. (91/1506) described a system for AAS analysis which consists of a powder sampler an integrated microbalance and a microprocessor controlled transport and handling system for the sample boat. Generally however handling of solids is a more difficult process to automate than that of solutions. Haswell et al. (91/C773) have therefore adopted an alternative approach to automated solid sample analysis in which slurries of the material to be analysed were passed continu- ously through a microwave oven and digested on-line.This novel approach may prove to be useful in eliminating some of the particle size limitations which have restricted application of direct sluny nebulization for sample intro- duction in atomic spectrometry. An expert system for real- time control of an atomic absorption spectrometer may also be of interest (9 11468). 3. ADVANCED MATERIALS This section of the review is concerned with developments made in the characterization of advanced materials using atomic spectrometric techniques. It is evident from the literature that there has been an increase in activity in this field in the past year particularly in respect of the analysis of high-purity inorganic materials. This area has been widened in the current review to include catalysts which are essentially materials with a highly specific functionality derived from an inorganic structure (e.g.noble metal on alumina). In previous ASU reviews in this series informa- tion on the characterization of catalysts had been included in the Chemicals section because of the strong association with that industry's operations. However in view of the growth of the inorganic materials sector it is considered that developments in methodology for the characterization of catalysts is now more usefully presented in association with the ceramics and refractories topic since similar analytical problems are encountered. A summary of analyti- cal methods for the analyses of advanced materials is given in Table 3. 3.1. Polymers and Composites A number of reviews have been published in the period covered by this ASU.The characterization of plastic materials using surface analysis techniques [e.g. SIMS electron spectroscopy for chemical analysis (ESCA) and LMMA] has been surveyed (9112340). The application of atomic spectrometry to the analysis of advanced materials has been discussed within the context of present capabilities and likely future needs particularly in respect of the direct characterization of solids (9 1/837). Specific reviews have been published on the application of transmission electron microscopy in materials science (9113476) and on the use of total reflection XRF in forensic work including the examination of plastics inks and fibres (9 112648). There has been a significant increase in the last review year in the use of laser ablation as a means of sampling polymer based materials for examination by MS.Laser desorption FTMS was utilized for the determination of mixtures of sodium alkyl benzene sulphonate ionic surfac- tants on textiles (9 112258). The identification of indigo dyed fibres was achieved using LMMS to fingerprint the materials (9 112 175). Both atomic and molecular ions produced by the laser beam induced evaporation were used in discrimination of the fibres on the basis of the mass spectra obtained. The classification of polymers using LMMS has been aided by the application of pattern recognition in distinguishing spectral features (9 112 165). The mass spectra of 19 different polymers were obtained in the range 0-300 u at three different laser irradiances and linear discriminant analysis was performed on the principal component data using the Resolve software package.It was shown that the mass spectra were distinct and could be easily differentiated using this pattern recognition ap- proach. Other examples of the use of LMMS in the306R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1 99 1 VOL. 6 TABLE 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS Technique; atomization; analyte form* Sample treatmenthmments Element Matrix Reference POLYMERS AND COMPOSITES- Al Paint aerosols SEM-XRF or SIMS M - ; S or L Bulk paint samples and aerosol size fractions Determination of distribution of As ions in ion Material dissolved in hot nitric acid; B determined in Sample heated in DMF 1-2 drops of acetic acid analysed to determine element mass distribution implantation masks range 250-1290 ppm added and cooled solution diluted with acetone; detection at 228.8 nm HC1; silicates if any volatilized with H,SO,-HF; solution diluted to 50 ml with water and analysed for Cu at 324.7 nm detection of F at major levels; precision 1-2% at 30% F level 10 g of sample ashed and extracted with 20 ml of Layered structure dispersive element used for As for As As for Cu; detection for Mn at 279.5 nm Sample preparation as for cd detection at 283.3 nm Collaborative trial to evaluate the precision of method recommended method published Microwave assisted digestion of samples claimed to improve recoveries Sample is calcined at 650 "C and ash treated with formic acid to reduce the palladium oxide formed; solution evaporated residue dissolved in aqua regia and diluted with water Depth profiling of migration of S as sulphate through 200 pm thick coating Investigation of bloom and other surface defects using SEM with X-ray spectrometer facility Samples treated with organic solvents and diluted with acetone; interferences investigated Six types of white paint were found to have Ti contents in range 19-33% Sample introduced into instrument in form of stable oil-water emulsion by adding IBMK and Brij-30 Depth profling of flame retardant material for Cl Sb Si and Zn by progressive removal of thin layers of sample using a lathe Graphite furnace pretreatment of solid sample followed by laser ablation into ICP-MS instrument for qualitative survey analysis of PVC polypropylene synthetic rubber and paints Direct qualitative and quantitative analysis of nylon polypropylene polyethylene and polyester using laser ablation sampling Quantitative analysis for Ca Mg Na and Si as oxides in identification of paint used in coatings Determination of pigments additives and coating layers using energy dispersive instrument Quantitative analysis of solid polymers by laser ablation Samples prepared by embedding beads or powders in epoxy and microtoming thin sections; differentiation of polymers by pattern recognition on LMMS spectra Mapping of spatial distribution of ions in a variety of matrices Direct quantification of Al Ca Fe K Na and Si using wavelength dispersive instrument Determination of inorganic components (unspecified) in base material by X-ray microanalysis 9113506 9 1 I234 1 9111 133 91/13 As Polyimide B Carbon fibre- epoxy composites Cd Poly(viny1 chloride) M,F;L M,ETA,L cu Rubber M,F;L 9113116 F Poly(tetduoroethy1ene) XRF;-;S 9111592 M&! Polyimide Mn Rubber Pb Poly(viay1 chloride) Pb Paint SIMS M,F;L M,ETA;L M-;L 9112341 91/31 17 91113 9 11 1039 Pb Paints AE;ICPL 9 llC2026 Pd Acrylonitrile rubber M,F;L 9 113045 S Phenolic coating S EPDM rubber Sn Poly(viny1 chloride) Ti Paint Zn Plastics Various (4) Nylon PIXE-;S 9113384 9 1 I3470 91194 9111 168 91/71 1 9014 1 64 SEM;-;S M F or ETA;L Electron probe or M,F;L M,F;L xw,-;s Various Polymers and paints MS;ICP;S 911104 Various Polymers MS;ICP;S 91lC751 Various (4) Paint Various Paper Various Polymers Various Polymers xw,-;s xw,-;s MS;ICP;S MS$aseqS 9111 182 9 llC17 19 91x1923 91/2165 Various Polymers Various (6) Polyethylene Various Vinyl adhesive tape MS;laser,S xw,-;s XRF;-;S 91/21 79 9112543 9112565JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 307R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Technique; atomization; analyte form* MS;ICP;S Element Matrix Various Plastics Sample treatmentfcomments Laser ablation sampling using internal standard for semiquantitative analysis accurate within a factor of 2; quantitative data agreed well with XRF and NAA data Reference 91/3205 SEMICONDUCTORS Al Al Al Al Al Al Al As As As As As B B Bi Silicon wafers AA;-;L Impurities remaining on the wafer are collected into the liquid resulting from the reaction of the oxide and HF vapour Use of tetrabutyl ammonium chloride as a sensitizing agent; matrix interference from iron and calcium was eliminated by standard additions Zeeman-effect background correction.(Detection limit 8 ppm) resonant transitions to enhance ion yield for time- of-flight MS Measurement of aluminium content in matrix layers of nm thickness Samples were decomposed in HN0,-HF-H,02 and after evaporation residues were dissolved in HCI; variations in sample preparation for different techniques reported; comparison of methods See ref. 91/929 Direct introduction of gas through base of ICP torch; gas handling rig allowed mixture of argon hydrogen silane and arsine in precise amounts measurement at interfaces and in bulk sputtering rate in each layer to translate intensity-time signal into concentration-depth Two-dimensional profiling of shallow (sub-pm) As doped regions As for Al Microsampling technique used in conjunction with Direct laser ablation of sample by tuning to known Study of thin layered material using arsenic Quantification using relative sensitivity factors and 91/464 Industrial silicon AA;F;L 91/929 Industrial silicon AA;F;L 91/1469 Aluminium gallium arsenide MS;laser;S 91/2289 Aluminium gallium arsenide Silicon SIMS or TEM 91/2367 9 1/295 1 AA or AEETA or ICP or DCPL 91/3011 91/858 Industrial silicon Silane AA;F;L MS1CP;G Gallium phosphide- Titanium disilicidel silicon gallium arsenic phosphide SIMS SIMS 91/2270 91/2301 Silicon Silicon Gallium arsenide SEM 91/2308 9 11295 1 91x1 738 AA or AEETA or ICP or DCP;L MS;r.f.spark$ Semiquantitative analysis with claimed 20% accuracy using relative sensitivity factors. (Range of B levels found from ppm to sub-ppm) As for As Silicon dioxide-titanium Cadmium mercury telluride disilicide-silicon SIMS AA;ETA;L 91/2301 91/924 Layers of material ( 5 mg) were removed by etching with 2.5% bromine in 4 mol dm-3 HBr detection using Zeeman-effect background correction. (Detection limit 0.4 ppm Bi) As for B. (C measured as low as 150 ppb) Response for Ca enhanced by presence of tetrabutyl ammonium chloride; normal calibration could be used Samples were analysed by layer following oxidation and etching; Cd fluorescence detected at 228 nm and method reported to be free of systematic error Calibration was camed out using external standards consisting of thin films of doped gelatine on pure wafers; accuracy confirmed by FAAS As for Bi.(Detection limit 0.14 ppm Cu) Sample ashed in oxygen to remove tellurium the residue dissolved in HN0,-H,SO (1 + 5) and Cu concentrated on Pt rod electrode which was part of HCL assembly. (Detection limit 10 ppb of Cu) implantation before and after annealing Depth profiling of Er concentration resulting from As for A1 Use of high-resolution instrument to avoid spectral Determination camed out using normal calibration interference on Fe curve; see Ca C ca Gallium arsenide Industrial silicon MS;r.f. spark$ AA;F;L 91fC1738 91/30] 1 Cd Cadmium mercury telluride AF;ETA,L 91/ 1104 c o Silicon wafers XRF;-;S 911164 c u c u Cadmium mercury telluride High-purity tellurium AA;ETA;L AE;HCL;S 91/924 91/3056 Er Silicon SIMS AA,-;L MS;ICP;L AA;FL 9 112325 Fe Fe Silicon wafers Electronic grade reagents 91/464 9 lfC1897 Fe Industrial silicon 91fC3011308R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Technique; atomization; analyte form* SIMS Element Ga Gd Ge H Hg In K Li Na Na 0 0 P P Tb Te Various Matrix Silicon and silicon dioxide multilayers Metallic thin film on silicon wafer Gallium arsenide Sample treatment/comments Liquid metal ion source based on Ga used to achieve Quadrupole spectrometer used for depth profiling at Study of extent of Ge migration from high-resolution depth profiling sub-pm resolution nickel-germanium-gold ohmic contacts to gallium arsenide Instrument operated in direct bombardment mode and H detected using quadrupole analyser by monitoring SiH As for Cd; tellurium was found to interfere with Hg determination by cold vapour method Direct determination using platform furnace with Zeeman-effect background correction; recoveries in the range 94-108% reported Study of matrix effects in the determination of alkali metals; sample dissolved in 6 mol dm-3 HCl- 14 mol dm-3 HNO (3+ 1) and diluted with H,O.(Detection limit for K was 1.6 ppb) As for K. (Detection limit for Li was 0.2 ppb) As for K. (Detection limit for Na was 1 ppb) As for Al As for B. (0 measured as low as 50 ppb) Study of oxygen diffusion through silicon dioxide Study of phosphorus diffusion; evidence for As for A1 coating on silicon wafer segregation of dopants along dislocations found Reference 9112265 91lCl778 9 1/23 1 3 9 112346 9111 104 911429 911219 91/219 911219 9 11464 91lC1738 9112594 9 112305 9112951 78 04 11 MS;GD,S SIMS Silicon hydride films MSsputtered neutra1s;S Cadmium mercury telluride AF;cold vapour;L Indium-mercury cadmium telluride AA;ETA;S Cadmium mercury telluride AE;F;L Cadmium mercury telluride Cadmium mercury telluride Silicon wafers Gallium arsenide Silicon dioxide coatings AE;F;L AE;F;L MSr.f. spark$ SIMS AA;-;L Silicon TEM or SIMS Silicon AA or AE; ETA or ICP or DCP;L MS;GD;S Metallic thin film on silicon wafer Cadmium mercury telluride Electronic grade quartz As for Gd 91x1 91/1 91/ AF;ETA;L MS;ICP;L As for Cd; Te fluorescence was detected at 214 nm Sample dissolved in mixture of HN0,-H,SO,/HF evaporated to dryness; residue dissolved in HCl-HNO and evaporated again with final dissolution in 2% HNO,; comparison with NAA AAS XRF and AES Total reflection instrument with rotating anode X-ray tube and monochromatic primary radiation used to improve SIN for detection of As Cr Cu K Ni and V Complex extraction of matrix in organic solvents and determination of impurities in aqueous phase; ppb detection limits The Pd Pt and Ru were isolated in turn by extraction with three different organic solvent systems and Ir remained in the aqueous phase Direct sample introduction of pyrophoric gases using specially designed five inlet ICP torch.(Detection limits reported at low ppb levels) bromine water; arsenic eliminated by evaporation and gallium by extraction; impurities Ba Co Cr In Ni Te and Zn dopant determined in resultant aqueous phase Separation of Bi Cd Cu Fe Mg Mn Ni Sr and Zn from matrix by pre-concentration on cellulose Hyphan collector and elution with 2 mol dm-3 HC1.(Detection limits 10-250 ng g-I) Extraction chromatography using HDEHP on PTFE with 0.5 mol dm-3 HNO elution or TBP on PTFE with 0.5 mol dm- HBr to separate radionuclides of impurity elements from those of the matrix methods for determination of As Cr Cu Fe Ge Ni and Sb impurities; accuracy assessed by NAA Quantification of ten dopant elements using caesium primary ion beam Sample decomposed with mixture of HCl and Comparison of acid decomposition and fusion Various (6) Silicon wafers XRF;-;S 91/147 Various (1 7) Trimethyl gallium and trimethyl aluminium AE;-;L AA;ETA;L MS;ICP;G AE;ICP;L 9 1/345 9 1/397 9 1lC760 911919 Various (4) Silicon Various (30) Electronic-grade gases Various (7) Gallium arsenide Various (9) High-purity gallium AE;ICP;L 9 1 /C940 Various Indium NAA 91lC1733 Various (7) Silicon MS;ICP;L SIMS 9 1/C 1736 9 112269 Various (10) Gallium arsenide and indium phosphideJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 309R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Various (1 1) Various Various (20) Various (5) various Various Various (6) Technique; atomization; Matrix analyte form* High-purity silicon AE;ICPL Silicon on insulator XRF-;S High-purity cadmium AE1CP;L and zinc High-purity gallium AA;ETA;L Gallium indium and AEiICP- bismuth compounds High-purity gallium ESCA or High-purity gallium M,ETA;L MS;spark;S Various (24) High-purity tellurium Various (1 9) Molybdenum disilicide GLASSES- Al Pharmaceutical glass containers B Borosilicate glasses c o Commercial glass Cr Commercial glass c u Zirconium fluoride Er Optical fibre precursors Ge Glass optical fibre Ni Zirconium fluoride P Glass optical fibre REE ( 14) NIST SRM 6 10 Glass REE NIST SRMs 610 6 12 and 6 14 Glass Various (6) NIST SRMs 6 10 612 614 and 1003a Glass Various Opaque red glass MS or AA,spark or ETA;S AA or AE;ETA or 1CP;L AA;ETA,L x-ray emission;-;S AE;ICP;S AE;ICP;S AA;ETA;L AE1CP;L AE;DCP;S M;ETA;L AE;DCP;S MS;spark;S SIMS AA,ETA,L Electron probe or AE1CP;L Sample treatmentlcomments Pressurized dilution of the sample in dilute HNO,; recoveries for Al Ba Ca Cu Fe K Mg Na Pt Si (as oxide) and Zn were in the range 96-1 10% heavy metals on sample surface chromatography with trioctylamine and tributyl phosphate-PTFE using HCl elution Extraction of Cd Co Cu Fe and Ni as pyrrolidine dithioformates into IBMK in the presence of tartarate Direct technique described with limits of detection at the sub-ppm range; error of 15% reported Trace element residues determined at 10- lo0 ppb level Gallium in the matrix was converted into trichloride and volatilized by gaseous HCl; residual impurities (Al Cd Cu Fe Mg and Pb) were dissolved in 0.25 mol dm-3 HNO and determined at ng g-I level sieved to a grain size of 100 mesh and homogenized in an inert atmosphere in a shaker; powders were mixed to provide a concentration range; AAS results used to provide relative sensitivity factors for SSMS Sample was dissolved in HF-HN0,-H,SO diluted and passed through a Dowex cationexchange column to remove the matrix and analytes were eluted in 2 mol dm- HNO Total reflection X-ray instrument used to detect Acid digestion in autoclave followed by extraction Samples (pure and impure) were powdered and Samples were heated in an autoclave for 1 h at 120 "C; aluminium released into distilled water measured at 5 ppb spectrometry was used to measure B.(Detection limit of 20 ppm reported) introduced to the ICP as a slurry; detection of inorganic colourant Low-energy electron-induced X-ray emission Samples were ground dispersant added and As for Co Analysis of 30% m/v solutions for Cu using Zeeman- effect background correction and platform atomization.(Detection limit of 3.2 ng g-I Cu reported) High-temperature disgregation of the sample was adopted; wavelength of detection was 337.376 nm. (Detection limit of 0 . 0 3 ~ ml-l was reported) Direct insertion of fibre via feed mechanism beneath plasma base; recoveries in the range 107- 1 16% for approximately 250 ppm of Ge As for Cu. (Detection limit of 6.3 ng g-I of Ni reported) As for Ge; recoveries for P at 335-805 ppm level were in the range 100-1 10% Powdered standard was briquetted with equal mass of graphite and analysed using %i as an internal reference Quantitative analysis for REEs using relative sensitivity factors for calibration Materials were powdered and suspended in 3% vlv HF solution; matrix silicon is removed as fluoride and analyte is extracted into aqueous phase for detection of Cu Co Cr Mn Fe and Ni Microanalysis of solid for major and minor elements of lead silicate glasses coloured by copper(1) oxide Reference 9112380 91t2589 9 1 lC2877 9113240 9113261 9113389 9013980 9014007 9014023 91lC1715 9 1lC1806 9 llC2922 9 1x2922 91189 9 1lC2926 911874 91189 911874 9 1/22 1 5 90x4045 911196 9 11932310R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Technique; atomization; analyte form* XRF;-;S Element Matrix Various Glass fragments Sample treatmenthmments Energy dispersive XRF with lateral resolution of 0.3 mm was used in SEM to identify small glass fragments Samples of ZrF were decomposed by evaporation with H,SO and dissolution in dilute HNO,; BaF and LaF were decomposed by HClO and dissolved in HCl; AlF was fused with sodium carbonate and dissolved in HC1 with H,O Samples were powdered and surface contamination cleaned using HCl; samples dissolved in HF-HCl then HClO and diluted to volume with HC1 Acid leachates were analysed for the presence of alkali metals and alkaline earths in order to study corrosion effects identification of glass fragments (by detection of Ca Fe Sr and Zr) and ICP for ten elements using dissolution Direct quantification of bulk and trace elements with a spatial resolution of better than 10 pm.(Detection at the low ppm level) techniques for determination of contaminants at the sub-ppb level Comparison of energy dispersive XRF for A survey of sample preparation and use of the above Reference 911962 9111251 9111427 lC1741 lC2036 9112323 9 113396 Various (4) Zirconium fluoride glass precursors M,F;L Various (48) Window glass fragments MSICPL Various Stained glasses AA or AE;-;L Various (10) Glass fragments XRF or AE1CP;S or L Various Alkali-borosilicate glasses SIMS Various Metal fluorides and fluoride glasses AA or MS;ETA or 1CP;L CERAMICS AND REFRACTORIES- Al Tungsten oxide B Boron carbide AA ETA L Sample was decomposed with ammonium citrate Sample loaded in the form of a slurry; detection of H,O and ammonia; sensitivity reported as 15 pg the dicaesium metaborate cation to determine isotope ratio Sample dissolved in HNO and Ba measured to sub- ppm levels without interference at 455.03 or at 493.409 nm when europium or terbium oxides were present Use of HCl and HNO treatment to distinguish between phases of differing chemical composition Detection of Br as indium chloride after introducing indium as an indicator metal into hollow cathode discharge Sample powder of sub-pm particle size was dispersed ultrasonically in water and the slurry introduced into the ICP; C was detected at 193,091 nm producing high count rates for light elements such as C same ion was used for bombardment; C emission yield used for quantification Separation of Cd using strong cationexchange resin and elution with 5 mol dm-’ HCI and ultrasonic desorption Use of layered synthetic microstructures for Caesium ions were implanted in the films and the As for Br 9 113004 9119 MS; thermal ionization;S Ba Rare earth oxides AE1CP;L 9 11 1008 Ba Br Superconductor Aluminium oxide 9 112 1 57 9 11347 AEF;L Molecular emission; HC,S Silicon nitride AE;ICP;S 911108 C C Superconductor films Electron micro probe 911122 C Titanium carbide films SIMS 9112267 Titanium dioxide AA;ETA;L 9113 107 Cd Aluminium oxide Molecular M F L XRF;-:S emission;HC,S 9 1 I347 c u c u Superconductor Superconductor 6lms As for Ba Standardization procedure for determination of Sample introduced into the atomizer as a 0.25% m/v Cu:Ba and Cu:Y ratios in oxide films slurry of powder in ethanol-water (9+ 1); measurements at 294.4 nm ion-exchange resin; detection at 356.166 nm using standard additions in the range 6- 1000 ppm Separation of Hf from matrix using Ag 1-X8 Biorad Wavelength dispersive instrument used to detect Hf 9 1121 57 9 113098 Aluminium oxide AA;ETA;L 911845 Ga Hf Zirconium oxide AE;ICPL 9 113 141 Hf Zirconium oxide XRF-;S 9 113296JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 31 1R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix K Tungsten oxide Na Tungsten oxide Nd Ceramic pigments Pb Superconductors Pb High-purity yttrium oxide Sr Rare earth oxides V Zirconia Y Superconductor Y Yttria stabilized zirconia Zr Hafnium oxide REE (1 4) Thulium oxide REE (8) Europium oxide Technique; atomization; analyte form* AA;FL AA;€L AE or XRFFL or S AE;ICPL AA,FHy AEICP;L AEICP;L AERL AEICP;L XRF-;S AE;ICP;L AE;ICP;L REE (1 4) High-purity europium oxide XRF;-;S Various ( 16) Zirconium carbide and nitride AE;ICPL Various (5) Aluminium oxide-chromium AEICP;L oxide powders Various (22) Barium titanate AEICP;L Various (4) Superconductor AA;FL Various Ceramics AE;arc;S Various (1 1) Rare earth oxides AE; d.c.arc;S Various (9) Barium titanate Various Superconductors AA or AE; F or 1CP;L AE;ICPL Various (7) Aluminium nitride AE;ICP;L and zirconia Various (8) Refractory SRMs AE;ICPL Various (7) Zirconium oxide AE;ICP;L Sample treatmentlcomments Sample was dissolved in ammonia cooled HNO caesium chloride and then citric acid and water added; K was determined in the supernatant liquid As for K Samples were either dissolved in HCl diluted and analysed using N,O-C,H flame or pelletized for XRF Speciation of PblV by recovery of insoluble residue; Pb" determined by difference from total Pb content Generation of hydride with sodium tetrahydroborate; RSD of 1 1% for measurement of 2 ppm of Pb As for Ba; Sr measured at 421.552 or at 407.771 nm in the presence of europium oxide Solvent extraction of V using potassium butyl xanthate in pH range 0.009-2.5 As for Ba Powders were decomposed with H,SO under pressure Powdered sample was pressed into a pellet and and diluted with 10% vlv HCl analysed by WDXRF with a tungsten anode tube and lithium fluoride crystal (Zr measured in the range 0.0 1-4%) Effect of organic solvents studied recoveries in the range 82-1 10% reported and RSDs of 1.9-9.3% Optimization of instrumental parameters to minimize interferences in detection of Ce Dy Gd La Nd Pr and Sm Impurities detected by reduction with zinc powder adsorption by P507 levextral resin elution with HCl and precipitation with ammonia; measurement on filtered precipitate limits in the ppb range; comparison with AAS data The powder was dissolved under pressure in 5 ml of H,SO and diluted with water to 100 ml and analysed for Ca Fe Mg Na and Ti Pressure decomposition of sample with HC1 or fusion with sodium carbonate or lithium borate; detection of majors and 20 impurity elements Examination of inter-element interferences in determination of Bi Ca Cu and Sr; effects removed by addition of sodium chloride Preparation and analysis of standard materials for spectral analysis based on ceramic oxides of Al Si Y and Zr containing also Ca Fe Mg Na and Ti as impurities signals in determination of trace elements in rare earth oxides Microwave assisted digestion of sample in HCl followed by extraction with APDC with chloroform and re-extraction into HNO yttrium-barium-copper oxide.(Al Mg and Zr found at levels between 50 and 250 ppm) Study of sample preparation and selection of suitable instrumental parameters for determination of Al Ca Fe Mg P Si and Ti development of methodology for detection of Al Ca Fe Mg Mn S Si and Ti pressure evaporated to dryness with HC10 and diluted with water prior to determination of Al Ca Cr Fe Mg Ti and Y Samples were digested in HNO and H F detection Study of effect of chloride salt carriers on emission Determination of contaminants in Introduction of samples as 1% m/v slumes; Powdered sample was dissolved in HF under Reference 9 11 1480 9 111480 9113284 9113159 911414 9 11 1008 9112539 9112157 9113031 9113174 911392 9 11 1024 9 111226 91180 91183 91197 9 11222 911270 9 11393 9 1 lC483 9 11C549 9 1 I836 911864 9111015312R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Technique; atomization; analyte form* AE;ICP;L Element Matrix Various (6) Superconductors Sample treatmentlcomments Samples were dissolved in HCl and an internal standard added Nitrides were digested under pressure using acid and zirconia was decomposed by carbonate-borate fusion A method for preparing standards containing Co Cry Cu Fe Mn Ni and Pb as impurities to pure matrices was described for calibration of instrument for analysis of refractories Fe Mn Ni and Pb using diethyldithioformate and CCl with recoveries >90%; detection by Pre-concentration and extraction of Cd Co Cr Cu ETV-ICP-OES Precipitation of Co Cu and Ni by addition of 142- pyridiylazo)-2-napthol and separation from tungsten by complexation with ammonia Measurement of major constituents including Ba Bi Ca Cu Pb Sr and T1 by dissolution in HNO Precision of better than 5% reported for quantification of Cay Fe Na S Si and T1.(Detection limits at 10 ppb level for 30 s integration) Major components Ba Bi Ca Cu Pb Sr and T1 in a variety of materials Quantitative elemental profiling in Bi-Sr-Ca-Cu-0 layers for majors minors and traces Comparision of sulphated decomposition and acid dissolution with carbonate-borate and lithium borate fusion procedures determination of Co Cu and Ni by addition of sodium docecyl sulphate effect decomposition for determination of Mo Ti V and Zr Direct examination of sample deposited on thin Mylar sheet provided ng level detection using PIXE but poorer sensitivity by EDXRF Comparison of fusion extraction and slurry methods; calibration by standard additions; good agreement for Al Ca Fe Mg Na Ti and Y using slurry method Laser ablation sample introduction for both sources in determination of Dy Er Eu and Yb Pressure dissolution of sample in HN0,-HF-fuming H,SO for 8 h followed by AAS or direct analysis of a 1% d v aqueous slurry by ICP-OES Optimization of instrument conditions and selection of wavelengths for detection of La Pb Ti and Zr and many impurities IBMK.(Detection limits in range 1-10 ppm and Elimination of interference from tungsten on Samples were heated in an autoclave with HF to Detection of Dy Eu Sm Tb and Y in 30% vlv RSDs 2.6-5.3%) Sample fused in caustic-peroxide and dissolved in HCl and detection of Ca Fe and Mg at 422.7 248.3 and 285.2 nm respectively Method described for determining the composition of thin films of superconducting materials Fundamental parameter method used to detect Al Ca Fe K Mg Na Si and Ti present as oxides Quantitative analysis for Ba Cu 0 and Y using a matrix correction procedure Use of 20% NaF as carrier enhanced spectral intensities by inhibiting evaporation of tungsten trioxide dissolution in dilute HC1 addition of lanthanum and coprecipitation as hydroxide then redissolution of solid and analysis by ICP-AES Fusion of sample with nitrate and carbonate then Reference 9111 161 AE;ICP;L Various Boron and aluminium nitrides and zirconia 9111 171 Various (8) Refractory borides carbides and nitrides XRF;-;S 9111217 Various (8) Lanthanum oxide AE;ICP;L 9111340 Various Tungsten oxide 9111473 AA;F;L Various (6) Superconductors Various (6) Alumina powder AA or AE;F or 1CP;L MS;GD;S 9 111 60 1 9 1 IC 1 654 Various (7) Superconductors AA or AE;F or 1CP;L SIMS AE;ICP;L 91lC1725 91lC1728 9 1 IC 1754 Various (10) Superconductor Various (1 5 ) Calcia partially stabilized zirconia Various Tungsten oxide AA;F,L 9112370 Various (4) High-purity alumina AE;ICP;L 9 112409 XRF or PIXE Various Superconductors 9112588 Various ( 10) Zirconium dioxide AE;ICP;L or S 9 llC28 1 3 Various (4) Yttrium oxide Various Silicon carbide AE;ICP or FANES$ AA or AE;ETA or 1CP;L or S 91lC2867 91lC2892 AE;ICP;L 9 1 lC29 1 9 Various (29) Ceramics Various ( 5 ) Gadolinium oxide AE;ICP;L 13010 13093 I3 134 13360 Various Silicon nitride AA,F;L Various Superconductors Various (8) Alumina-silica refractory Various (4) Superconductor Various (28) High-purity tungsten trioxide AE;ICP;- XRF-iS Electron probe AE;d.c.arc;S 9113364 9 113498 Various ( I 1) Silicon nitride AE1CP;L 9014025JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 313R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix CATALYSTS- c1 Reforming catalysts c o Boron modified cobalt- alumina catalysts Pt Reforming catalysts Pt Aluminium oxide Pt Molecular sieve catalyst Rh Catalysts Various Catalysts and alumina support Various (1 6) Zeolite fluid cracking catalysts Various (4) Heterogeneous catalysts + REE Technique; atomization; analyte form* Sample treatment/comments XRF-;S EXAFS XRF-;S AA;ETA;L M F L AE;ICP;L M F L AE;ICP;L AA;FL Energy dispersive instrument with rhodium target modified with an aluminium foil filter; calibration using external catalyst standard amounts of colbalt oxide and cobalt surface phase on catalyst Matrix correction for absorption used in quantification of Pt The sample was boiled with aqua regia washed and diluted with HCl then precipitated with tin(I1) chloride washed digested in aqua regia and diluted Pressurized digestion in aqua regia-HF and addition of copper sulphate solution; detection at 265.9 nm Solvent extraction of Rh with potassium hexyl xanthate into xylene; interference of nickel avoided by preextraction with butyl xanthate The A1 matrix was masked with potassium oxalate and Cd Cu and Pb were separated by adsorption on sulphydryl cotton and re-eluted with HC1 Acid digestion using ‘Spectrasol’ reagents which deactivate HF without using boric acid Microwave digestion of samples under pressure using HN03-H3P04 for detection of Co Fe Mo and Ni Cross correlation analysis used to detect relative Reference 9 113295 9 112966 91156 911453 9112381 91185 9 11 1093 9 1 lC2093 91/2471 *Hy indicates hydride generation and S L G and S1 signify solid liquid gaseous or slurry sample introduction respectively.Other abbreviations are listed elsewhere. investigation of polymer systems included a study of the reactive selectivity of oligomers in polyglycol samples to alkali metal ions (91/2179) and the application of an FTMS instrument for full mass range scanning on a single laser shot (91/2169). Laser ablation has also been used as a means of introducing polymeric materials to an ICP-MS instrument (91/C751 91/C1629 91K1923). A detailed report on the application of laser ablation ICP-MS to the analysis of a range of filled and unfilled plastics has now been published (9113205). It was reported that semi- quantitative analysis of polypropylene nylon poly(viny1 chloride) polyethylene and polyester could be achieved with an accuracy of a factor of two or better by ratioing to carbon as an internal standard.Quantitative analysis achieved employing calibration standards yielded good agreement with results obtained using other techniques such as WDXRF and NAA. The influence of instrumental parameters on the analytical performance which can be achieved by laser ablation ICP-MS has also been studied by the same workers (91/C820). It was found that the position of the beam focus had a considerable influence on both the magnitude of analyte intensities and the precision obtained. It was considered that operating the Nd:YAG laser at a focus about 10 mm above the surface of the polymer sample yielded best precision and results consistently below 1 Ooh RSD could be achieved for elements in the mid-ppm concentration range.Laser ablation has also been used in conjunction with ICP-AES for the analysis ofpolymers and paints (9 1 / 104). A graphite furnace was incorporated in the ablation chamber which allowed the electrothermal pre-treatment of samples prior to evaporation using the laser. Emission signals were detected using a multi-element emission spectrometer. The system was used for qualitative scanning or survey analysis but quantification was hindered by a lack of calibration standards. Paints were also examined directly using XRF (9111 182 91/C1719 9113506) and electron probe micro- analysis (9 1/1168). Results of a collaborative trial evaluat- ing the precision of an official method for the determination of total and soluble Pb content of dry paint films have been published (9 1/1039).British Standard chemical tests for the analysis of raw and vulcanized rubber by FAAS published in the last year may also be of interest (9 1/3 1 16 9 1/3 1 17). Traditional methods of sample preparation for the analy- sis of plastics such as ashing or wet oxidation are relatively slow and can be subject to losses particularly for the determination of volatile elements in a matrix such as poly- (vinyl chloride) (PVC). One alternative is to make use of the organic nature of the polymer by using a dissolution approach (see J. Anal. At. Spectrom. 1990 5 347R). This involved treatment of the PVC sample with dimethyl formamide and adding a few drops of acetic acid and then diluting with acetone prior to analysis by FAAS.This pre- treatment has now been used for the determination of Cd and Pb in PVC using ETAAS (91113) and Sn in PVC by both FAAS and ETAAS (91/94). In a related approach Zn was determined in plastics by FAAS following treatment of the sample with IBMK and Brij-30 an emulsifier. The resultant oil-water emulsion formed was found to be sufficiently stable to be introduced directly into the flame. The method was suitable for the determination of Zn in the range 0.1 to 1 ppm. Glow discharges have as yet not been applied to the analysis of polymeric materials owing to difficulties in sustaining the plasma with non-conducting samples. The use of r.f. supported discharges obviates the need for a conducting sample allowing the direct analysis of insula- tors (911C2799 91/C2800,91/C2850). It is to be hoped that such developments will continue allowing the depth profil- ing capability of the GD to be used in the examination of314R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL.6 polymers. The related technique of sputtered neutral MS offers a similar potential (9 l/C278 1). A few abstracts were received concerning the application of SIMS to the study of polymeric systems. The distribution of Mg and As ions in polyimide were determined experimentally using SIMS (91/2341). The surface of a polycarbonate material was treated using a carbon tetrafluoride-oxygen plasma dis- charge and the surface of the sample examined by SIMS and XPS (9112324). It was found that with very low amounts of oxygen in the gas feed extensive fluorination of the surface occurred and perfluorinated islands were formed.How- ever under conditions of high oxygen supply very low amounts of fluorine only were observed on the surface of the polycarbonate and etching took place. The use of a DCP discharge cleaning method to eliminate background from perfluorinated polyalkylethers in SIMS analysis may also be of interest (91/2302). 3.2. Semiconductor Materials Interest in the development of new or improved methods for the analysis of semiconductor materials remains high with over 100 abstracts received for the period under review. Of these the great majority (>60) were concerned with the characterization of silicon-based materials. Several review articles which discussed the available spectro- analytical techniques and their relative merits in applica- tions from the electronics industry may be of general interest (91/281,91/282,91/1075,91/2272).A survey ofthe use of the AA AE SSMS NAA and laser techniques for the analysis of high-purity germanium has also been published (9 112407). Undoubtedly SIMS remains an indispensable tool for the characterization of semiconductor materials. A general overview of the potential of SIMS for the analysis of very large scale integrated silicon devices is highly recommended (91/2366). One of the major problems in the application of SIMS remains that of correlation of ion response with concentration (i. e. quantification). Progress towards iden- tifying a suitable semiconductor standard for quantification has been assessed (9014 1 36).A three-stage implantation of 2sSi followed by loB implantation at 50 keV was reported to produce a material with a smooth B depth distribution. Low dose energetic ion implantation has also been pro- posed as a method for depth scale calibration in SIMS (9 1/2280). However it was considered that implantation conditions including species and energy had to be optim- ized for the particular problem. Calibration is particularly problematic as the complexity of multi-layer systems grows. An analytical method for the quantitative depth profiling of titanium-silicon multi-layer samples has been published (91/2301). In this approach a processing algorithm con- verted the dopant (B or As) intensity time profile into concentration by applying sensitivity factor and sputtering rate corrections for each layer.The use of the depth projling capability of SIMS has been reported in a range of applications. The nature of hydrogen- ated silicon films on chromium gallium arsenide and titanium substrates have been examined using SIMS with oxygen bombardment (9 1/228 1). The interf'ace between the film and the substrate was examined by changing the angle of the primary ion beam. Boron-doped hydrogenated silicon was examined by SIMS (9 112333) and sputtered neutral MS (9 1/2346). Several publications were devoted to SIMS depth profiling of silicon-germanium layers (91/2279 91/2295 91/2348) the latter of these being hydrogenated. The application of a new type of sputtered neutral MS to the depth profiling of germanium-silicon multi-layers was also described (9 1/2271).It was claimed that this new system labelled SNART offered high sputter- ing rates with minimal matrix effects post-ionization and as a consequence accurate quantification. The character- istics of silicon-silicon oxide layers were determined by using a gallium ion liquid metal ion source as the primary beam to trace the yield of implanted gallium (91/2265). Gallium was found to be a good marker for thin oxide layers at a silicon-silicon interface and the technique gave improved spatial resolution. The accumulation of Fe at the silicon-silicon dioxide interface has also been studied by SIMS (9 1/2299). Other applications reported included the use of SIMS to assess distribution of Cu and Ga in silicon using oxygen bombardment (9112276) and a study of Er implanted in silicon before and after rapid thermal anneal- ing (91/2325).There was considerable interest in the application of electron microscopy to the characterization of silicon-based materials. The advantage of techniques such as SEM is that it is possible to obtain two-dimensional information (lateral and depth profile) at high resolution (9112308). Thus dopant As concentrations were delineated in shallow regions of a silicon sample using an HF etching procedure followed by cross-sectional SEM examination. A relative positional accuracy of 15-20 nm was claimed. In a similar study one- and two-dimensional dopant profiles were obtained for p-n junctions in etched silicon specimens using both scanning and transmission electron microscopy (91/2309).The SEM method was applied to diodes with junctions 2 pm deep and the TEM approach devoted to fully processed bipolar transistors with junctions 130 nm deep. The profiles obtained were found to be in good agreement with SIMS data. Indeed TEM can be used to study surface alterations on silicon wafers induced as a result of SIMS analysis (9 112306). Oxygen bombardment of the surface at 4.5 keV of a silicon sample was found using TEM to produce an amorphous layer 20 nm deep. An accumulation of As at the altered layer was found following SIMS profiling of an As doped sample. This approach is also useful in the study of residual damage in silicon wafers following dopant ion implantation (9 112307). The effect of boron difluoride implantation was studied using TEM and Raman spectroscopy.It was found that the distribution of B and F and the residual morphological damage had a significant effect on the electrical properties of the im- planted layer. Other applications of TEM reported included a study of the dopant profiles of B and P implants in silicon (9 1/2305) silicon oxynitride implanted layers (9 1 /23 lo) As and B doping of titanium silicide (91/2311) and Co implantation in silicon (9 1 /23 12). There were relatively few reports concerning the applicu- tion of GD-MS to the analysis of silicon-based semiconduc- tors and very little indication of conference presentations of previous years finding their way into the primary literature. A GD instrument using a quadrupole mass spectrometer was shown to be able to detect Gd in a metallic thin film on a silicon wafer (91K1778 91K2109). The use of cryo-cooling of the ion source was claimed to minimize interferences allowing the use of a lower resolu- tion detector.A few papers were published concerning the use of XRF for the direct analysis of impurities in silicon wafers (91/147 91/164 91/2589). A review of the prin- ciples and applications of XRF using the total reflection geometry is recommended to those with an interest in this field (9 1 /2400). Inductively coupled plasma mass spectrometry continues to find application in the determination of impurities in silicon (91K1736) and in electronic grade quartz (91/111). There have been some interesting developments in the direct analysis of electronic-grade reagents by ICP-MS.A number of precursor gases used in semiconductor pro- duction are pyrophoric and in the case of silane are also toxic (91/958). Thus a gas handling rig was constructed which allowed the accurate mixing of argon 1% silane andJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 315R gas standards for the determination of As (25 ppm v/v arsine in argon) and I (25 ppm v/v methyl iodide in argon) and this was connected directly to the central injector of the ICP torch. Standardization was achieved via dilution of the arsine and methyl iodide standard gas mixtures on line. Quantification was also achieved by ratioing analyte inten- sities to that for the silicon matrix which was used as an internal standard. Detection limits for As and I in silane were given as 0.55 and 0.65 ppb respectively.A high- temperature aerospace alloy was used to fabricate the MS sampling cone to reduce deposition of the refractory matrix. The cone glowed a dull red colour during operation and it was found that signal integrity could be maintained for longer periods using this modification. The use of a low- pressure MIP torch was also found to eliminate orifice deposition in this type of analysis (911C1628). In another approach to the same problem a five-inlet ICP torch was designed for the analysis of pyrophoric semiconductor gases (911C760). Detection limits for over 30 elements were reported at ppb levels. The detection of Fe by ICP-MS is well known to be limited by the spectral background from argon oxide.The use of ETV for sample introduction to the ICP-MS has been shown to remove this interference (911C1617 911C1897). The detection limit for Fe in the analysis of high-purity semiconductor-grade acids was reported to be of the order of 10-20 ppt using this technique. It was implied that further improvement in the detection limit could be made by using a magnetic sector instrument instead of a quadrupole mass filter but no details were given in the abstract. Applications of ICP-AES to the determination of trace elements in high-purity silicon (91/2380) and in molyb- denum disilicide (9 112380) have been described. However there was little work of any great novelty reported in the year under review using ICP-OES. These comments also apply to developments in AAS where relatively few applications merit comment.Graphite furnace applications involving the determination of platinum group metal dopants in silicon (91/397) impurities on the surface of silicon wafers (911464) and trace impurities in molyb- denum disilicide (9014023) have been reported. A review of the principles of laser AAS and its application to the determination of concentration profiles of Bi Pb and Ru in thick multilayer electrical structures may be of interest (9 1/95 1). The characterization of gallium arsenide-based semicon- ductors using AA and AE techniques was the subject of a recent review (9 113303). However there were relatively few abstracts received relating to these techniques for the analysis of gallium based semiconductors in the year under review and only some of these are worth highlighting. The determination of impurities and dopant concentrations in zinc-doped gallium arsenide by ICP-OES has been reported (91119).The sample was treated sequentially by cleaning and decomposition with hydrochloric acid and bromine water and elimination of matrix elements by evaporation of arsenic and extraction of gallium. A range of analytes including Ba Co Cr In; Ni Te and Zn were determined in the aqueous phase resulting from the sample preparation stage. Detection limits were reported to be in the ng g-l range. Trimethyl gallium is an important precursor in semiconductor manufacture but is difficult to analyse because of its pyrophoric nature. A separation process was proposed based on the conversion of gallium into a chloride form by treatment with 6 mol dm-3 hydrochloric acid (91/345).The reaction was carried out in a Fluoroplast reaction vessel in an inert gas atmosphere. Impurities were separated from the matrix by extraction of HGaCl with oxygenated solvents. A reducing agent such as hydrazine or ascorbic acid was added to prevent coextraction of Fern and Zn. After separation of the Ga the remaining aqueous phase was heated to dryness and the vessel washed with hydrochloric acid. The resulting solution was then analysed by AE for the determination of Al Ba Ca Cd Co Cr Cu Fe K Mg Mn Na Ni Si Ti V and Zn. Detection limits in the ng g-' range were reported. The detection of trace element impurities in high-purity gallium has also been carried out using separation-extraction procedures.A num- ber of analytes including Cd Co Cu Fe and Ni were extracted as pyrrolidinedithioformates into IBMK in the presence of tartarate (91/3240). These elements were then detected in the extract by ETAAS. The advantage of the method was considered to be low experimental blanks made possible by the one-step matrix removal and pre- concentration procedure. In a different approach Ga was volatilized as the trichloride following treatment with gaseous hydrogen chloride (90/3980). Residual impurities were dissolved in 0.25 mol dm-3 nitric acid and were detected using ETAAS. Recoveries obtained by this method were in the range 92-105% for Al Cd Cu Fe Mg and Pb. Detection limits were given in the 1.5- 1 1 ng g-l range. The advantage of this method was reported to be a reduction in the risk of contamination.Mass spectrometric techniques continue to be employed for the analysis of high-purity gallium and related materials. For example RIMS has been used in depth pro$Zing of doped gallium arsenide and aluminium gallium arsenide layered structures (9 11C625). Quantification was made possible by normalizing dopant signals to that of the matrix assuming similar sputter rates. Laser ablation RIMS using a time of flight mass spectrometer has been utilized for the detection of As Ca and Ga in an aluminium gallium arsenide sample (9 1/2289). Improved sensitivity of several orders of magnitude was achieved by tuning the ablation laser to match the resonant atomic transitions for As and Ga using the same dye laser. Spark source MS is an extremely sensitive technique for the analysis of gallium- based semiconductors.The distribution of trace element impurities in high-purity gallium was studied by SSMS (91/3389). It was found that trace elements could be detected in the range 10-100 ppb using this technique. A radiofrequency spark source MS system was applied to the determination of semi-insulating gallium arsenide and its precursors (911C1738); samples were sparked under ultra- high vacuum using a pulsed voltage generator. The resultant ions were focused onto an ion sensitive Q-plate by means of electrostatic and magnetic sectors. Mass spectra were interpreted using a computerized optical microdensito- meter. It was reported that microphotometric measurement of dopants and residual impurities allowed reliable semi- quantitative analysis with an accuracy of 20%.In undoped gallium arsenide only B and 0 were detected as residual impurities. Surface analysis techniques such as secondary ion mass spectrometry (SIMS) continue to be applied to the charac- terization of gallium-based semiconductor materials. Car- bon- l 3 doped aluminium gallium-aluminium gallium ar- senide superlattices were subjected to impurity induced disordering by silicon and zinc and the resultant materials were examined by SIMS (9 112349). The modulation depth of the SIMS "Al and 13C signals was used as a probe of sublattice interdiffusion. Both silicon and zinc were found to enhance carbon diffusion in the matrix. The description of a focused ion beam which is claimed to combine the capabilities of ion microscopy ion lithography SIMS and ion milling in a single instrument is likely to be of general interest to workers in the semiconductor field (9112303).The system was applied to a SIMS scan across a gallium arsenide-aluminium gallium arsenide heterojunction. Gal- lium and indium phosphide materials have also been examined by SIMS. Examples reported included the analy- sis of gallium arsenide-gallium arsenide phosphide layered316R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 structures (91/2270) and a study of ion yield in the measurement of ten dopant elements in gallium arsenide and indium phosphide materials (9 1/2269). Studies involv- ing plasma secondary neutral MS indicated that the elemental sensitivity factors found in the examination of gallium arsenide gallium phosphide and indium phosphide materials were dependent on mass differences of the components (91K2851).It was reported that the relative sensitivities could be less than one order of magnitude for masses of less than 100. New methods for the analysis of cadmium mercury telluride and precursors continue to be proposed and these are summarized conveniently in Table 3. The role of analytical techniques in the study of matrix components and impurities in cadmium mercury telluride was discussed in a review (91/3390). Amongst the techniques considered were AAS XRF SSMS LMMS and SIMS. The last has been used in depth profiling of impurities in layer grown cadmium mercury telluride (9112275). Layer by layer analysis of the main components in cadmium mercury telluride has been carried out using an oxidation and etching process followed by AF detection (91/1104).The high sensitivity of AF for the determination of Cd Hg and Te coupled with the use of ETA allowed a depth resolution of 10 nm to be achieved. An AA method was also described for the layer by layer determination of impurities in cadmium mercury telluride (9 1/924). Layers were removed using 2.5% bromine in 4 mol dm-3 hydrobromic acid. A Zeeman-effect background corrected ETA method was proposed for the detection of Bi and Cu in 5 mg layers. Detection limits in the sub-ppm range were reported. A Zeeman-eflect background correction system was used to good effect in the direct determination of In in solid indium cadmium mercury telluride by ETAAS (9 1/429).A zircon- ium coated platform was used which was reported to eliminate interferences from halides. Indium recovery was in the range 94-108% and the RSD was less than 6% for the method. A comparison of the relative merits of ETAAS SSMS and GDMS for the analysis of high-purity tellurium may also be of interest (9014007). 3.3. Glasses Ceramics and Refractories 3.3.1. Glasses A review by workers from NIST on the characterization of high-purity metal fluorides and fluoride glasses has been published (91/3396). Emphasis was given to aspects of sample preparation for these materials and methodology associated with ICP-MS and ETAAS detection of elemental impurities at the sub-ppb level. A graphite furnace AA instrument with Zeeman-effect background correction was used for the detection of Cu and Ni ppb levels in zirconium fluoride (91/89).The sample was introduced to the instru- ment as a 30% m/v solution of zirconium fluoride. Palladium nitrate and nitric acid were used as chemical modifiers in conjunction with platform atomization which helped protect the tube from erosion. The technique was validated by recovery experiments and by the use of the standard additions procedure. Detection limits for Cu and Zn were reported to be 6.3 and 3.2 ng g-l respectively and RSD values were typically less than 10%. A slurry extraction method was developed for the analysis of glass materials by ETAAS (9 1/ 196). Samples were powdered and suspended in water containing 3% hydrofluoric acid.The slurries were prepared in autosampler cups and were agitated by passing argon gas through the solution which served to mix the slurry and remove the matrix as silicon tetrafluoride. Analyte metals such as Co Cr Cu Fe Mn and Ni were extracted into the aqueous phase of the slurry. A range of NIST glass standards were analysed using the method and the results compared with a conventional digestion procedure. Inductively coupled plasma emission spectrometry has also been used in conjunction with slurry sampling metho- dology for the analysis of glasses (9K2922). The glass samples were ground and introduced to the plasma in the form of an aqueous slurry stabilized by the addition of a dispersant. Factors such as the particle size the amount of suspended solids present and the influence of different dispersing agents were studied.One of the advantages of ICP-OES compared with AAS for this type of analysis is that data can be rapidly gathered on a multi-element basis. Thus it is possible to use this information to discriminate the source of glasses by elemental fingerprinting (91K2036). In this study 81 samples of automobile side glass windows were analysed by ICP-OES using a sample dissolution procedure. It was found that the levels of at least ten elements detected by ICP-OES allowed identification of the source of the glass. It is possible to use ICP-MS for elemental fingerprinting of glasses (see J. Anal. At. Spec- trom. 1990 5 350R). Details of a conference presentation on this subject have now been published (91/247).The concentration of some 48 elements were determined by ICP-MS following acid dissolution of typically 4% or less. Tests performed to assess the selectivity of the method towards glass type indicated a success rate in discriminating the source of origin of 85% of American window glass samples and 90% of Australian glass samples. Dissolution of glass samples can be extremely time consuming and methods are required which can analyse solid samples directly. Laser ablation ICP-MS appears to offer promise combining the rapidity of sampling with high sensitivity particularly for rare earth elements. However even in this case it would appear that some benefit may be obtained from performing sample preparation analysis (9 1 /C2823). It was found that borosilicate glass was easier to sample by laser ablation if the specimen surfaces were etched or frosted instead of being smooth.An alternative method of solid sampling suitable for the analysis of glass fibres has now been published (911874 see also J. Anal. At. Spectrom. 1990 5 350R). The glass fibre was continuously fed into a DCP (modified to include a thin sample feed tube inside the standard sample introduction tube) and directly atomized. The resultant AE signals were detected optically using an Cchelle spectrometer. It was found that glass fibres with a high silica content such as optical fibres with high melting- points could be analysed with acceptable accuracy by integrating the optical signal generated. This was not possible with low melting-point glasses such as soda lime as the fibres tended to sag or bend with heat.In such cases the sample was introduced in a pulsed manner with a residence time of less than 10 s in the DCP. Signals were then measured as peak heights on a chart recorder and averaged. Results obtained using the continuous method showed reasonable agreement with known values of Ca Ge and P in fibres. However it was concluded that the pulsed technique was innaccurate based on results from the analysis of soda lime glass television screen glass and lead glass. X-ray spectrometric techniques have also been used for the examination of glasses. Energy dispersive XRF has been suggested as a potential method of distinguishing between glass types (91/C2036) but it has also been reported that the technique can suffer from size effects which affect X-ray intensities (9 1/962).A new technique known as low-energy electron induced XRF has been applied to the determina- tion of B in borosilicate glasses (91K1806). Low energy X- ray emission was induced by secondary electrons produced in a glow discharge. The emission was detected using an X- ray vacuum spectrometer utilizing a lead stearate crystal analyser. The detection limit for B in glass was reported to be 20 ppm. There were also reports of the application ofJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 317R EXAFS to the examination of glasses. These included a study of the role of Fe and U in the corrosion of sodium borosilicate glasses (9 1/3376) an investigation of diffusion properties of oxide glasses and glass surfaces (9 113377) and a study of the structural environment of Mn and Sr in the dry and hydrous silicate glasses (9113459).An example of the use of a radiofrequency powered glow discharge for the analysis of NIST SRM multicomponent glass by AES may also be of interest (91/878). 3.3.2. Ceramics and refactories The advent of high-temperature superconduclors several years ago stimulted a demand for analytical methodology for the characterization of these materials. Most of the techniques for inorganic analysis have now been applied to the task but reports on sample preparation methodology continue to appear. These are summarized in the appropri- ate section of Table 3. The analysis of thin films of superconducting material is becoming increasingly impor- tant and as a consequence methods for examining solids directly are being explored.X-ray techniques offer the advantage of non-destructive analysis which is important in the study of unique structures. Thus EDXRF has been used to determine the composition of thin films of superconduc- tor material (9111532) and has been compared with PIXE for a similar application (9 112588). Various film substrates were used including thin Mylar sheet and thicker magne- sium oxide alumina and strontium titanate backings. It was found that EDXRF provided superior detection limits to PIXE for Ba Cu and Y (in the mid-ng range) on thin backing and that the use of thicker backing materials degraded these considerably. A method for the preparation of standards for the determination of Y:Cu and Ba:Cu ratios in a superconducting yttrium-barium-copper oxide film by XRF has also been reported (9113098).Scanning- beam X-ray diffractometry was used in the determination of phase composition of superconductor films (9 1/3057). It was recommended that the technique was used for the examination of films more than 1 nm thick. In a novel approach AAS was used to monitor and control the deposition rate of semiconductor on substrates (911111). Since the light beam from the HCL could be passed through the vapour stream this enabled the region of sampling to be very close to the surface of the substrate thus permitting estimation of the composition of the film being deposited. This information was used to control the composition of the film as it was developed. Thin layers of superconducting material have been de- posited by laser ablation prior to analysis by MS (9 112288) or SIMS (9 11C1728 9 112283).In the latter case PIXE and Rutherford backscattering were also used to characterize the samples. A review of the application of Rutherford backscattering to the examination of superconducting oxide thin films has been published (9113493). A time-ojflight atom probe which yields high sensitivity chemical atom detection with atomic resolution imaging capability has been described (9112365). The instrument consisting of a field ion microscope and a time-of-flight mass spectrometer with a positron sensitive detector was applied to the study of surface segregation in a yttrium barium copper oxide superconductor.The analysis of rare earth oxides continues to receive attention although it should be pointed out that the majority of the abstracts received contained information at least a decade away from current awareness. Most publica- tions revisited sample preparation methodology or re- discovered the inherent spectral interference problems associated with ICP-OES for the analysis of such samples. This information is available for reference in Table 3. The use of a high-resolution spectrometer system to minimize spectral intei$erences in REE matrices may be considered useful reading in this context (91/865). A slurry introduc- tion procedure for the determination of trace elements in zirconia by ICP-OES was compared in terms of analytical performance with conventional procedures involving fu- sion with ammonium sulphate followed by dissolution or extraction of the resulting residue (9 1/C28 13).The slurry procedure consisted of ultrasonic dispersion of the zirconia powder in water acidified with hydrochloric acid. It was found that good agreement was obtained between the slurry and conventional procedures for the determination of Al Ca Fe Mg Na Ti and Y. Laser ablation provides an alternative method of introducing solid samples into the ICP (9 11866). A laboratory constructed carbon dioxide laser (spot size 0.24 mm) was used to ablate samples directly and a 1 m focal length spectrometer was used to measure REE signals from the ICP. Results indicated that this. approach was efficient for the determination of REEs. The direct analysis of REEs in yttrium oxide using laser ablation inside a graphite furnace has been described (911C2867).A ruby laser was used to ablate solid materials into a non-thermal plasma discharge sustained at low pressure inside the furnace. Detection limits and precision obtained for the more volatile elements were in the same range as for laser ablation ICP-AES. However the results obtained for the analysis of Dy and Er were not so favourable owing to the high energy required for the production of free atoms of these elements. The development of non-oxide ceramics continues and a great deal of effort has been devoted to establishing suitable methodology for quantitative analysis of these materials. Unfortunately the properties which make non-oxide cera- mics attractive (e.g.high temperature stability resistance to chemical attack) cause problems in sample preparation. Consequently much of the literature is devoted to the development of sample preparation procedures for opening out these structures prior to analysis by ICP-AES. Several abstracts were received concerning the use of slurry intro- duction procedures for ICP-AES. Broekaert and co-workers (9 1/C492,9 1/C2892) compared dissolution and slurry ICP- AES procedures for the analysis of silicon carbide. The dissolution procedure involving heating and sample for 8 h with a mixture of nitric hydrofluoric and sulphuric acids was also evaluated in conjunction with ETAAS. The slurry procedure required only that the sample powder was suspended in water and treated ultrasonically for 15 min.It was reported that provided the particle size of the sample was less than 10 pm accurate determination of trace impurities in the ppm range could be achieved using the slurry method. This finding was confirmed in a separate study comparing pressurized wet digestion of silicon car- bide with slurry analysis both by ICP-AES (911C2735). However it was observed that even when using a high power (2-4 kW) plasma accuracy was not always guaran- teed. Tracer experiments indicated that the largest particles were separated by nebulization and that transport efficiency was the limiting factor on accuracy for the determination. The C content of silicon nitride (particle size t 5 pm) was determined using a slurry ICP-AES method (911108). An extended torch was used to minimize the C blank and this was further reduced by the use of high-purity argon and suspension of the sample in fresh high-purity doubly distilled water.Calibration and addition methods were carried out using acetic acid as a reference C standard. A limit of detection of 0.018% C was reported. Finally impurities in silicon carbide were determined directly using solid sampling ETV-ICP-AES (91K228 1). A variety of thermochemical additives such as barium nitrate barium carbonate lead borate or sodium borate and volatilization aids such as potassium fluoride silver chloride and cobalt fluoride were evaluated both separately and in combina-318R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 tion for their efficacy in removing the sample from the electrically heated graphite crucible and introducing it into the ICP.The combination of barium nitrate and cobalt fluoride was found to be the most suitable and the methodology was used to determine Al Cr Mn Mo Ni V and W in silicon carbide powder. Sample preparation methods for the analysis of alumi- nium and silicon oxide based ceramics are listed in Table 3. The length of time required for these methods and their relative complexity has stimulated research to find simpler and more rapid means of characterizing these materials. The application of slurry sampling is increasing in popular- ity as an alternative to digestion procedures (9112232 91/2968 see also J. Anal. At. Spectrom. 1990 5 356R). Slurry-based methods have been proposed for the determi- nation of Ga in alumina by ETAAS (911845) and Pd and Pt in alumina by ETAAS (911C2152).However the high temperature of the ICP provides more effective atomiza- tion of refractory materials. Brenner and Long (911C771 9 1/864) utilized slurry sampling in conjunction with mixed- gas plasmas for the analysis of a number of refractory RMs including aluminium rich fire brick (NIST SRM 269) silica brick (BCS CRM 3 15) and silicate brick containing alumina (NIST SRMs 198 and 199). Slumes of 1% m/v composition were introduced to the ICP using a Babington type high solids nebulizer and analysed in plasmas containing 5% oxygen in argon 10% nitrogen in argon and pure argon. It was found that the argon-oxygen plasma exhibited the highest analytical sensitivity for Fe and Si.Other studies of aerosols produced by slurry nebulization of alumina pow- der indicated that evaporation is incomplete for particles with diameters exceeding a critical value (911C1767). Transport efficiency may also depend on particle morpho- logy (911C2803). Different shapes of particles were found on sampling above the plasma using a cascade impactor both in the case of alumina and silicon carbide. The fraction of each type of particle collected was dependent on plasma conditions indicating the need for optimization to make the best use of slurry sampling. Efforts continued towards developing direct solid sampl- ing methods for the analysis of oxide ceramics. Laser ablation ICP-MS has been increasingly cited as a promising method for the characterization of such materials (911C1772 911C1922 911C2809 see also J.Anal. At. Spectrom. 1990 5 356R). Sadly much of the work described in conference reports fails to appear subsequently in the primary literature. Nevertheless a number of groups appear to be agreed on the benefits of the method in this application. Examples of the applications of laser ablation ICP-MS cited this year include the analysis of ferrite ceramics using UV laser (91/C1920) trace analysis of alumina silicon nitride and zirconia (9 11C508) and unspe- cified ceramics and superconducting materials (9 1 1 0 10). An attempt to improve quantification of laser ablation ICP- MS using non-matrix matched standards for the analysis of ceramics based on the element enthalpy of atomization was unsuccessful (911C1925). This was attributed to the fact that the analytes were present in the form of oxides and carbides rather than the metal itself.Glow discharge mass spectrometry has also been proposed as a method for the ultra-trace level analysis of ceramics (9 11C782 9 11C173 1). The quantitative determination of Ca Fe Na S Si and Ti in alumina was demonstrated using a high-resolution GDMS instrument (9 1 /C 1 654). Precision of the order of 5% relative was achieved and calibration linearity was demonstrated over at least two orders of magnitude. Detection limits in the ppb range based on an integration time of 30 s were claimed. One of the difficulties in the application of d.c. powered GD sources is that non- conducting materials such as ceramics have to be mixed with a conducting host matrix in order to achieve a stable discharge.However the advent of r.f. powered GD sources should overcome this limitation. At least two different systems have now been constructed and applied to the analysis of ceramics but few details are available on analytical performance as yet (9 11C2006 9 l1C2855). Catalysts are essentially materials that are designed with in-built functionality. Their activity usually increases with surface area and consequently highly porous struc- tures such as those constructed from aluminas and zeolites provide ideal substrates for this activity. Consequently the chemistry of these systems is rather similar to that of ceramics and refractories and the structure of the review has been modified to include the abstracts relevant to catalysts in this section.The composition of catalyst materials is often confidential and methodologies tend to be reported in the open literature only in generic terms. Nevertheless a summary of the analytical methods specific to catalysts is given in Table 3. There was little innovation in this area in the year under review. Flame AAS methods have long been used in the petroleum industry for the analysis of catalysts. The determination of Co Fe Mo and Ni in heterogeneous catalysts by FAAS has been reported (9 11247 1). Microwave assisted digestion of the samples in closed vessels in a mixture of nitric and phosphoric acids was claimed to give total recovery of analyte elements without complete destruction of the sample. In another application of FAAS trace levels of Cd Cu and Pb in catalysts and alumina support were pre-concentrated from the matrix on sulphydryl cotton.The elements were washed off the cotton with hydrochloric acid and analysed directly. Plasma emission methods have been reported for the analysis of fluid cracking catalysts based on acidic decom- position (911C1734 91/C2093) rhodium catalysts (91185) and alkali media (9 1K2839). Automotive catalysts have been characterized by ICP-MS using microwave assisted dissolution for sample preparation (9 lK2073). X-ray fluorescence has been applied to the determination of chloride in reforming catalysts (9113295) and to the measurement of platinum in used reforming catalysts (91156). Finally the use of EXAFS for investigation of the cobalt phase on boron-modified cobalt alumina catalysts may be of some interest (9112966).A cross-correlation method of data analysis of the spectra was used to determine the relative amounts of cobalt oxide and cobalt surface phase present on the catalysts.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 199 1 VOL. 6 319R LOCATION OF REFERENCES The full list of references cited in this Update have been published as follows 9013592-9014 179 J. Anal. At. Spectrom. 1990 5(8) 36 1R-378R. 9111-911825 J. Anal. At. Spectrom. 1991 q l ) 41R-68R. 911826-911C1687 J. Anal. At. Spectrom. 1991 q3) 109R-136R. 91/C1688-91/2702 J. Anal. At. Spectrom. 1991 q4) 153R-185R. 9112703-911C2928 J. Anal. At. Spectrom. 1991 q5) 221R-227R. 9112929-9113584 J. Anal. At. Spectrom.1991 6(7) 257R-280R. Abbreviated forms of the literature references quoted (excluding those to Conference Proceedings) are given on the following pages for the convenience of the readers. The full references names and addresses of the authors and details of the Conference presentations can be found in the appropriate issues of JAAS cited above. Abbreviated List of References Cited in Update 9013952. Anal. Sci. 1990 6 97. 9013957. Spectrochim. Acta Part B 1990 45 119. 9013965. Spectrochim. Acta Part B 1990 45 271. 9013973. Spectrochim. Acta Part B 1990,45,427.90/3976. Spectrochim. Acta Part B 1990,45 615. 9013980. Anal. Chim. Acta 1989 226 193. 9013991. Zh. Prikl. Spektrosk. 1989,51 903.9013995. Anal. Chem. 1990 62 1155. 9013998. Fresenius Z. Anal. Chem. 1989 335 648.9014001. Fresenius Z. Anal. Chem. 1989 335 698. 9014006. Fresenius Z. Anal. Chem. 1989 335 893. 90l4007. Fresenius Z. Anal. Chem. 1989 335 900. 9014008. Fresenius Z. Anal. Chem. 1989 335 910. 90l4010. Fresenius Z. Anal. Chem. 1989 335 971. 90/4012. Fresenius 2. Anal. Chem. 1989 335 1005. 9014015. Fresenius J. Anal. Chem. 1990,336 120.9014023. Bunseki Kagaku 1990 39 19. 9014025. Bunseki Kagaku 1990 39 49. 9014027. Bunseki Kagaku 1990 39 171. 9014136. Second Ion Mass Spectrom. Proc. Int. ConJ 6th 1987 433 9014146. J. Anal. At. Spectrom. 1990 5 195. 9014157. J. Anal. At. Spectrom. 1990 5 269. 9014162. Analyst 1990,115,865. WI4164. Anal. Proc. 1990,27,186. 9014167. Bunseki Kagaku 1990 39 T17. 9014173. At. Spectrosc. 1989,10 144.9117. J. Anal. At. Spectrom. 1990 5 325.9119. Analyst 1990 115,911. 91/12. Analyst 1990 115 943. 91/13. Analyst 1990 115 955. 91/16 Appl. Spectrosc. 1989,43 1 132.91119. Appl. Spectrosc. I989,43 1187. 91/21. Appl. Spectrosc. 1989 43 1257. 91145. At. Spectrosc. 1990 11( l) 1. 91/50. Spectroscopy (Eugene Oregon) 1989 4 36. 91/56. Analysis 1990 18(l) 24. 91/77. Anal. Sci. 1990 6 803. 91180. Anal. Sci. 1990,6 3 15. 91/83 Bunseki Kagaku 1990,39 39.91184. 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