摘要:

Proceedinas - - - - - -of the Analytical Division ofThe Chemical SocietyPADSDZ133136138138153155159159160161162CONTENTSAnniversary DinnerReports of MeetingsSummaries of PapersTrace Analysis'in the Steel Industry'Spectroscopy''Simultaneous Multi-element'Atomic-absorption Spectrophotometry'One Hundred Years of AtomicSilver MedalObituary-A. E. HeronConferences and MeetingsPublications ReceivedAnal yti ca I Division DiaryVolume I2 No 5 Pages 133-1 62 May 197Vol. 12, No. 5 May, 1975PROCEEDINGSANALYTICAL DIVISION OF THE CHEMICAL SOCIETYOF THEOfficers of the Analytical Divisionof the Chemical SocietyPresidentG. W. C. MilnerHon. SecretaryP. G . W. CobbSecretaryMiss P. E. HutchinsonHon. TreasurerJ. K.ForemanHon. Assistant SecretariesD. I. Coomber, O.B.E.; D. W. WilsonEditor, ProceedingsP. C. WestonProceedings is published by The Chemical Society.Editorial: The Director of Publications, The Chemical Society, Burlington House, London, W1 V OBN.Telephone 01 -734 9864. Telex 268001.Subscriptions (non-members): The Chemical Society, Publications Sales Office, Blackhorse Road, Letch-worth, Herts., SG6 1 HN.Non-members can only be supplied with Proceedings as part of a combined subscription with The Analystand Analytical Abstracts.@ The Chemical Society 1975Analytical Division MeetingA Two-day Joint Meeting of the Groups and Regions onThe Application of New Techniques inEnvironmental Analysiswill be held atThe University of St. AndrewsonThursday and Friday, June 19th and 20th, 1975The programme, which includes a Plenary Lecture by Professor D.Bryce-Smith and 15 contributed papers, is given in full in theAnalytical Division Diary on the back cover of this issue.Further details and registration forms can be obtained fromDr. J. E. Whitley, Scottish Universities Research and ReactorCentre, East Kilbride, Glasgow, G75 OQU

ISSN:0306-1396    

DOI:10.1039/AD97512FX018

出版商:RSC    

年代:1975

数据来源: RSC

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MAYWednesday, 21st, 6.30 p.m.: LondonSouth East Region : Inaugural Meeting.“The Chemical Industry and AnalyticalChemistry-Three Ages,” by C. Whalley.Followed by a Cheese and Wine Party in theRooms of the Chemical Society.The Linnean Society, Burlington House,Piccadilly, London, W. 1.Wednesday, 28th, 9.15 a.m.: GlasgowScottish Region on “Atomic AbsorptionSpectrometry.”“Principles of Atomic-absorption Spectro-metry,” by W. B. Rowston.“Instrument Design,” by C. B. Mullins.“Clinical Analysis,” by I. Dale.“Agricultural Analysis,” by A. M. Ure.“Metallurgical Analysis,” by J. M. Ottaway.“Pre-concentration Techniques,” by A. M.Ure .“Recent Instrumental Developments,” byC. B. Mullins.“Filament and Furnace Atomisers,” by J. M.Ott away.The meeting will also include demonstrationsessions by the following manufacturers :Instrumentation Laboratory (UK) Ltd.;Perkin-Elmer Ltd. ; Pye Unicam Ltd. ;Rank Precision Industries Ltd. ; Shandon-Southern Ltd. ; and Varian Associates Ltd.Room C133, Thomas Graham Building, Uni-versity of Strathclyde, Cathedral Street,Glasgow, G1 1XL.JUNEThursday, 5th, 2.30 p.m.: LondonJoint Pharmaceutical Analysis Group : Meet-Speakers to include V. Goldberg and R. D. G.Pharmaceutical Society of Great Britain, 17ing on Original Papers.Woolfenden.Bloomsbury Square, London, W.C. 1.Friday, 13th, 3 p.m.: LondonElectroanalytical Group.“Micro Molar Analysis-Sinusoidal Hydro-dynamic Modulation at the Rotating Ring-disc Electrode,” by s. Bruckenstein.Imperial College, Lecture Theatre C, Chem-istry Department, South Kensington,(There will be no separ-ate notice of this meeting, and furtherdetails can be obtained from the HonorarySecretary of the Group, Dr.B. Birch,Unilever Research Laboratory, Port Sun-light, Cheshire, L62 4XN.). London, S.W.7.Analytical Division DiaryPrinted by Heffers Printers Ltd Cambridge EnglandThursday and Friday, 19th and 20th: St.Andrews.Joint Groups and Regions meeting on “TheApplication of New Techniques in Environ-mental Analysis.”Thursday, 19th-Plenary Lecture : “Rational Priorities forPollution Control,” by Professor D. Bryce-Smith.“The Continuous Monitoring of EffluentsUsing Ion-selective Electrodes,” by M. E.Hofton.“Determination of Steroids in Effluents,” byJ .P. Dawson and G. Best.“Variability in the Chemical Composition ofSea-water,” by E. J. Hamilton.‘‘The Application of Radionuclide Measure-ments to the Study of the Marine Environ-ment,” by J. W. R. Dutton.“Spark-source Mass Spectrometry of Soils,”by A. M. Ure.“Problems Associated with the Mass Spectro-metric Confirmation of Nitrosamines inFoodstuffs,” by T. Gough.“Studies of Lead in Exhaust Particulates byRadioactive Tracer Techniques,” by A.Morgan.Friday, 20th-“Legislation with Regard to Present andFuture Requirements,” by E. A. B. Birse.“The Automated Analysis of Fresh WaterSystems as a Means of Pollution Control,”by C. S. Franklin.“Polarographic Studies of Some OrganicPollutants in Water,” by W. F. Smyth,J. P. Hart and M. Hassanzadeh.“Biological Activity Measurement and itsApplication to Pollution Control,” by P.Coackley .“Recent Developments in the Analysis ofCarbon Monoxide in Air and Blood,” byB. T. Commins.“Multiple Pollutant Monitoring Using Spec-troscopic and Gas ChromatographicMethods in a Mobile Laboratory,” byP. A. Hollingdale-Smith.“Carbon Furnace Atomic-absorption Analysisof Atmospheric Particulates,” by J. M.0 ttaway .“Instruments for the Continuous Analysis ofAir Pollution in an Urban Environment,”by H. M. N. Stewart.Department of Chemistry, The University, St.Andrews, Fife. (See also inside front cover.

ISSN:0306-1396    

DOI:10.1039/AD97512BX020

出版商:RSC    

年代:1975

数据来源: RSC

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Vol. 12, No. 5 May, 1975 of the Analytical Division of the Chemical Society Anniversary Dinner The Biennial Anniversary Dinner of the Analytical Division was held at Goldsmith’s Hall, Foster Lane, London, E.C.2, in the evening of Friday, March 14th, after the Annual General Meeting. The reception was by the President, Dr. G. W. C. Milner, and Mrs. Milner and 72 members and guests were present. Dr.J. W. Barrett, President of The Chemical rather the weft in the total fabric of chemistry Society, and Mrs. Barrett were the Guests of that crossed the warps of all sectors of the Honour, and other guests of the President and subject, thus supporting them and keeping them the Division were Dr. A. J. Amos, Chairman of straight and continuous. Moreover, analytical the Trustees of the Analytical Methods Trust chemistry was a constantly changing amalgam Fund, and Mrs.Amos, Dr. C. B. Amphlett, of all areas of chemistry and other disciplines Head of the Chemistry Division, AERE, such as physics and biology. Although his Harwell, and Mrs. P. Amphlett, Dr. R. C. Chirnside and Mrs. Chirnside, Professor H. M. N. H. Irving, Mrs. A. G. Jones, Sir David Martin, Executive Secretary of The Royal Society, and Mrs.Martin, Dr. R. L. Mitchell, Miss J . D. Peden, President of the Association of Public Analysts, Mr. J. R. Ruck Keene, General Secretary of The Chemical Society, Mr. C. C . B. Stevens, President of the Pharma- ceutical Society, and Mrs. Stevens. The President receiving Miss J . D . Peden. DY. J. W. Barrett being received by Mrs.MiEner. The Loyal Toast was proposed by the President and then Dr. Barrett proposed the toast of Analytical Chemistry, expressing the hope that this Dinner would be the first of many occasions that would carry on the traditions of the SAC. Analytical chemistry, described by some as the handmaid of all chemistry, was early research has been in synthetic organic chemistry, Dr. Barrett recalled that analytical techniques were in constant use and the data obtained were essential to the progress of the synthetic research.The great advances made in analytical chemistry in the past 30-40 years were reflected in all areas of chemistry, particularly in industrial chemistry where much of the success must be attributable to the progress made since the Second World War in analysis by physical methods and its appli- cation to process control and monitoring.Chemical knowledge today pervaded all aspects of life, and the quality of life and the material needs of society were of prime con- cern. A major problem was the reliable prediction of the consequences of scientific innovation, and such predictions required the 133134 ANNIVERSARY DINNER Proc.Analyt. Div. Chern. SOC. Professor H . M . N . H . Irving with Dr. A . J . Amos and Mrs. Amos. constant use and extension of analytical chem- istry. An example was the detection of the penetration of polychlorinated biphenyls into marine and bird life, which had not originally been contemplated, and such situations would probably be better predicted today as a result of the increased power of analytical methods.In recent years, The Chemical Society had had increased demands placed upon it in order to live up to its Charter responsibilities to ensure that chemical science was applied to the maximum economic advantage to the UK and its community consistent with minimum risk. Such demands could not be met without bring- ing together all parts of the subject, and it was therefore most gratifying that the SAC had decided to amalgamate with The Chemical Society.In proposing the toast, Dr. Barrett coupled Analytical Chemistry with Analytical Chemists (or Practising Chemists, now immortalised by Drs. Chirnside and Hamence). They had been represented for the last 2 years by Dr. Milner, who had carried on the tradition of the great leadership of former Presidents.The President, in response, thanked Dr. Barrett and expressed the gratitude that former SAC members owed him for the understanding and patience that he had brought to the negotia- tions between the two Societies that ultimately resulted in amalgamation. Dr. Milner thanked Council and members of the Division for agreeing to the proposal that he should serve as President for a third year, during which period any difficulties consequent upon amalgamation should have been finally resolved.Recalling the SAC Centenary Celebrations held in July, 1974, he mentioned that the many The President and Mrs. Milner with Dr. C. B Amphlett and Mrs. P. Amphlett.May, 1975 ANNIVERSARY DINNER 135 tributes and awards presented to the SAC by kindred organisations throughout the world would be preserved by The Chemical Society in perpetuity.Dr. Milner reflected on the reasons for a small learned Society flourishing for a period of 100 years, and attributed it largely to the shrewd and able men who had been willing to lead the Society so effectively. The SAC had prospered from its publishing activities and its healthy financial position had been due mainly to such successful publications as The Analyst and Analytical Abstracts.I t was appropriate that the Society had entered into amalgamation while at the zenith of its activity and prosperity. Paying tribute to the support he had received from the Honorary officers, Members of Council and permanent staff during the previous 2 years, Dr.Milner mentioned especially Mr. W. H. C. Shaw, who was relinquishing the office of Honorary Secretary after 7 years of efficient service but would continue to serve the Division for the following 2 years as a Vice-president, Mr. J . K. Foreman, who had been Honorary Treasurer since 1973 and had played a major part in the amalgamation negotiations, and Miss. P. E. Hutchinson, the Secretary of the Analytical Division, who had completed 21 years’ service with the SAC in 1974. Finally, he reported on the healthy state of the Division’s Regions and Subject Groups.MY. P. G. W . Cobb (L) and Mrs. Cobb with MY. W . H . C . Shaw. The toast of the Guests was proposed by Professor H. M. N. H. Irving, and the response was by Dr. C. B. Amphlett. At the end of the evening, the President presented the Tenth Society for Analytical Chemistry Gold Medal to Dr.R. L. Mitchell, Director of the Macaulay Institute for Soil Research, for his work over many years on the spectrochemical analysis of soils , plants and related materials, particularly trace element analysis. A biography of Dr. Mitchell appeared in the March issue of Proceedings. Presentation of the Tenth SAC Gold Medal to Dr.R. L. Mitchell. In acknowledgement, Dr. Mitchell said that in the mid-1930s he had found himself at the Macaulay Institute with a few burettes, beakers and Bunsen burners, a flame-emission spectro- graph and a sound grounding in ana1,ytical chemistry imparted by Dr. J. E. Mackenzie, Dr. C. C. Miller and Dr. S. A. Kay at the Univer- sity of Edinburgh.Very soon the need had arisen to meet urgent requests for the determination of a number of fairly difficult elements in soils and plants at the parts per million level. He had had some success with flame emission and it seemed that a spectrographic technique might be devised. Arc emission appeared likely to give adequate sensitivity and reproducibility, provided that a concentration technique that would collect the required elements could be evolved and a reliable source could be developed.Dr. Mitchell took it that his invitation to be present at this function indicated that these hunches were correct. During the past 35 years he and his colleagues had been developing and applying the arc technique and, more recently, taking a renewed interest in flame methods, with sufficient success to persuade the Agricultural Research Council to approve and the Department of Agriculture and Fisheries for Scotland to make generous provision for equip- ment, including a Hilger 49-channel Poly- chromator and an AEI spark-source mass spectrometer, which would extend the coverage to more elements, more expeditiously.He, and the nine previous Gold Medallists, had received the ultimate specialised distinction136 REPORTS OF MEETINGS proc. Analyt. Div. Chew. SOC. that an analytical chemist could achieve. He thanked the President for making the presenta- tion so felicitously and invited him to express to the Honours Committee and the Council his most sincere appreciation of the honour they had done him by including him among the very select, so recognising also his colleagues and the whole agricultural research service.

ISSN:0306-1396    

DOI:10.1039/AD9751200133

出版商:RSC    

年代:1975

数据来源: RSC

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136 REPORTS OF MEETINGS Proc. Analyt. Div. Chem. SOC. Reports of Meetings CS Annual Congress The Division participated in the CS Annual Congress, held at the University of York from April 7th to llth, 1976. The central theme of the Congress was “A View Towards the 21st Century” and the subject of the AD Symposium, held on April 9th and 10th, was “Analytical Techniques Used in Industry.” On Wednesday, April Qth, the Chair was taken in the morning by Mr.J. K. Foreman and the following papers were presented and discussed : “Developments in the Analytical Control of Iron and Steelmaking,” by T. S. Harrison; “Applications of Carbon Furnace Atomic Spectrometry in Metallurgical Analysis,” by J. M. Ottaway, F. Shaw and R. Hutton; “An?lysis in the Electrical Industry,” by H.J. Cluley. The Chair was taken in the afternoon by Dr. G. W. C. Milner, and the following paper was presented and discussed : “Laser Micro- spectrochemical Analysis,” by R. McGillivray . This was followed by the fourth Theophilus Redwood Lecture by Professor P. Zuman, entitled “Polarography in Attacking Practical Presentation of scroll by the AD President, Dr. G. W . C. Milner, to the fourth Theophilus Redwood Lecturer, Professor P.Zuman ( R ) . and Theoretical Problems in Analytical Chemistry.” On Thursday, April loth, the Chair was taken in the morning by Mr. F. E. Harper. A discussion on “The Public Analyst and Public Health-a View Towards the 21st Century,” was introduced by L. E. Coles, J . Markland, F. C. Shenton and R. Sinar. The following papers were ’also presented and discussed : “Analytical Techniques in the Pharmaceutical Industry,” by A.Holbrook; Analysis in the Plastics Industry,” by D. C. M. Squirrell. The Chair was taken in the afternoon by Mr. D. W. Wilson, and the following papers were presented and discussed : “Analysis in the Petrochemicals Industry,” by D. R. Deans; “Analysis in the Paint Industry-Present and Future,” by L.A. O’Neill. Ordinary Meeting An Ordinary Meeting of the Division, organised by the Midlands Region, was held on Monday and Tuesday, April 14th and 15th, 1975, in the Haworth Building, The University, Bir- mingham 15. The subject of the meeting was “Data Acquisition and Processing.” The Chair at the opening session was taken by Dr. W. T. Elwell, and a t subsequent sessions by Dr.D. Thorburn Burns, Mr. S. Greenfield, Dr. P. B. Smith, Dr. D. A. Pantony, Dr. D. I. Coomber, Dr.T. B. Pierce and Dr. A. Townshend. On April 14th, the following papers were pre- sented and discussed : “Survey Paper on Correla- tion and Derivative Spectroscopy,” by D. C. Champeney ; papers by practising spectroscopists on “Infrared,” by R. P. Young; “Microwave,” by N.L. Owen; “Optical,” by M. L. Butler; “N.M.R.,” by R. T. Jones ; “Mass Spectroscopy -Basic Principles,” by A. Carrick; “Mass Spectroscopy-Elucidation of Original Struc- tures,” by N. A. B. Gray; X-ray Fluorescence- Matrix Corrections,” by P. Hurley ; “Photo- electron Spectroscopy,” by P. Powers ; “Reac- tion Rates,” by A. Townshend. On April 15th, the following papers were pre- sented and discussed: “Survey Paper on Unscrambling of Unresolved Peaks,” by A.B. Littlewood ; “Calibration Curves,” by H. McD. McGeachin; “G.L.C. Systems,” by P. B. Stockwell; “Nuclear Techniques”, by T. B. Pierce ; “Recent Advances in Centrifugal Fast Analysers and Methods to Assess Their Preci- sion,” by R. W. A. Oliver; “Differential Scan- ning Calorimetry,’’ by R. E. Waller; “Coding Chemical Structures by Means of the Wiswesser Line Notation,” by G.Palmer; “13C N.M.R. - I.R. Applications in Structural and QuantitativeMay, 1975 REPORTS OF MEETINGS 137 Analysis,” by I. K. O’Neill; “Spectrum Match- ing in a File (X-ray),” by I. F. Ferguson; “Data Processing as Applied in the Screening of Biochemical Data,” by Margaret Peters. North West Region An Ordinary Meeting of the Region was held at 7 p.m.on Wednesday, April 30th, 1975, at the Laboratory, E. R. Squibb & Sons Ltd., Moreton, Wirral. The Ch.air was taken by the Chairman of the Region, Dr. L. S. Bark. A lecture on “Pharmaceutical Analysis and Safety” was given by C. Daglish. Western Region A Joint Meeting of the Region with the South Wales Section of the Society of Chemical Industry was held at 7 p.m.on Wednesday, April 30th, 1975, in the Joint Students Union, Park Place, Cardiff. The Chair was taken by the Chairman of the Western Region, Dr. W. J. Williams. A lecture on “Bacteriological Control in the Food and Pharmaceutical Industry” was given by J . G. Davies. The meeting was preceded by a visit to Parke- Davis, Pontypool. North East Region A Joint Meeting of the Region with the North East Region of the CS Industrial Division was held at 10 a.m.on Wednesday, April 30th, 1975, a t ICI Ltd., Petrochemicals Division, Wilton, Cleveland. The Chair was taken by the Chairman of the North East Region, Mr. F. E. Harper. The subject of the meeting was “Analysis in the Petroleum Based Industries-A Critical Evaluation of the Present Position and Future Development in the Primary and Secondary Industries” and the following papers were presented and discussed : “Cracker Analyses, ” by G.E. Penketh; “Refinery Analyses,” by F. W. Venables; “Plastics Analyses,” by Diana Simpson ; “Fibres Analyses and Identification, ” by B. F. Sagar; “Analytical Research,” by J. Mortimer. East Anglia Region and Radiochemical Methods Group A Joint Meeting of the East Anglia Region and the Radiochemical Methods Group was held at 11.15 a.m.on Thursday, April 24th, 1975, at the Huntingdon Research Centre, Huntingdon. The Chair was taken by the Chairman of the East Anglia Region, Mr. A. W. Hartley. The subject of the meeting was “The Use of Radioisotopes in Metabolic Studies” and the following papers were presented and discussed : “The Use of Radioisotopes in Metabolic Studies in Animals,” by R.N. Woodhouse; “The Use of Radioisotopes in Metabolic Studies in Man,” by G. H. Draffan. The meeting was followed by a tour of some of the research facilities at the Huntingdon Research Centre. Thermal Methods Group The Fourth Thermal Analysis School of the Group was held from Monday to Friday, April 7-1 1 th, 1975, at the University, Salford.During the week the following papers were presented : “Thermometric and Enthalpimetric Methods,” by L. S. Bark; “Thermogravimetry,” by D. Dollimore; “Differential Thermal Ana- lysis,” by F. W. Wilburn ; “Thermomechanical Methods,” by A. Dyer; “Gas Analysis Methods in Thermal Analysis,” by D. L. Griffiths; “The Surface Area and Texture of Powdered Materials Subjected to Heat Treatment,” by D.Dollimore; “Applications of Thermal Analysis in Organic Chemistry,” by R. E. Waller; “Applications of Thermal Analysis in Inorganic Chemistry,” by D. V. Nowell; “Applications of Thermal Ana- lysis in Materials Technology,” by J. H. Sharp. The school also included practical classes in the laboratory, and concluded with a Thermal Analysis Talk-in. Particle Size Analysis Group An Ordinary Meeting of the Group was held at 2.15 p.m.on Thursday, April loth, 1975, in the Department of Chemical Engineering, The University, Bradford. The Chair was taken by the Chairman of the Group, Dr. W. Cam. The subject of the meeting was “Size Separa- tion Techniques” and the following papers were presented and discussed : “Aerosol Separa- tion by Electrostatic Methods,” by J. I. T. Stenhouse; “The Fritsch Analysette 8 Air Classifier for Preparative Separation and Par- ticle Size Analysis,” by A. Taylor ; “Experiences with the BAHCO Centrifugal Dust Classifier,” by L. Svarovsky; “A New Method for the Determination of Droplet Size in a Liquid - Liquid Dispersion,” by J. G. Marsland; “Drop Size Measurement in Opaque Liquid - Liquid Systems,” by J. de Carvalho and M. J. Slater; “The Alpine Zig-Zag Classifier,” by M. H. Prior.

ISSN:0306-1396    

DOI:10.1039/AD9751200136

出版商:RSC    

年代:1975

数据来源: RSC

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138 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS R o c . Analyt. Div. Chem. SOC. Simultaneous Multi-element Trace Analysis The following are summaries of two of the papers presented at a meeting of the SAC/AD on November 6th, 1974, and reported in the November issue of Proceedings (p. 284). The Silver Medal Address by Dr. G. F. Kirkbright presented at that meeting appeared in full in the January issue (p.8). Sources for Atomic-fluorescence Spectrometry in Multi-element An a I ysi s R. F. Browner Department of Industry, Laboratory of the Government Chemist, Cornwall House, Stamford Street, London, SE19NQ Historically, atomic-fluorescence spectrometry (AFS) has occupied a similar but comple- mentary position to atomic-absorption spectrometry (AAS) . It has, in addition, provided the advantage of lower detection limits for a number of elements.Published data show AFS to have superior detection limits (2x or greater improvement) to either AAS or flame atomic-emission spectrometry (FES) for 21 elements1 (conversely, the reverse applies for 23 elements). In spite of this, AFS has not achieved the same popularity as AAS in analytical use. Undoubtedly, a major contributory factor to this situation is the difficulty experienced with unreliable radiant sources.The direct proportionality between source radiant output and atomic-fluorescence signal (at low metal concentrations, and using non-laser sources) can cause poor reproducibility if the source is unstable. Possibly the major advantage that AFS possesses over AAS is its multi-element capability. This results principally from the longer linear working range (typically 3 x lo3 with EDL sources and 106 with laser sources) compared with AAS (typically 10’).In multi-element work, where widely different concentrations of elements may be present in the same sample, a long linear range is essential in order to avoid calibration difficulties. Also, the optical arrangement of a number of sources around an atom cell is much simpler with AFS than with AAS, and the resolution requirements of the spectral isolation device are much less stringent than in either AAS or FES.In fact, in AFS the atoms act as their own monochromator, and non-dispersive devices may be used in conjunction with interference filters (which are necessary only to reduce background noise).Multi-element AFS systems have been described by Norris and West,2 Malmstadt and Cordos3 and Mitchell and Johansson.* The first uses two dual-element EDLs and the others use pulsed hollow-cathode lamps. However, the major limitation in any multi-element AFS system is the source performance. Major requirements for satisfactory sources are high radiant output over the absorption line, long- and short-term stability, simple tuning and alignment, availability for a wide range of elements, possibility of incorporating several elements per source, long shelf-life and operating lifetime, safety of operation and low cost.Two of the most promising sources for multi-element AFS are the thermostated multi- element EDL5 and the tunable dye laser.6 Thermostated EDLs, which can operate with five elements per lamp, offer the possibility of inexpensive multi-element AFS with simple equipment, and provide a good linear dynamic range.The tunable dye laser, whilst costing far more than EDL systems, can give very low detection limits in AFS. With suitable dyes, it is possible to operate the laser to a low wavelength limit of 265 nm by frequency doubling the output with a non-linear crystal.Several multi-element EDL systems have been des- cribed in the literature.’ However, these have not been thermostated, which has generally restricted construction to two or three elements (or compounds) of similar volatility per lamp. The thennostated “A” antenna system5 allows a more rational approach to be applied to multi-element EDL.By appropriate choice of fill material and operating temperature, lamps containing up to five elements can be constructed simply. Fig. 1 shows the operation of a zinc - cadmium - copper-iron lamp. The expected loss of fluorescence signal, which would result from operation of the lamp at a selected, compromise temperature, can be seen for each element.The extreme temperature sensitivity of EDL (approximately lo3 x change in radiant outputMay, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 139 per 150 K change in source temperature) that is seen in Fig. 1 necessitates precise temperature control, particularly for multi-element lamps. With these sources, operation is usually not possible on a peak or plateau region of the intensity ‘ I ~ ~ Y S U S temperature curve.Consequently, regulation to approximately 0-1 K is required for 1 per cent. stability. 373 473 573 673 773 Temperature /K Fig. 1. Atomic-fluorescence signal versus temper- ature for Zn - Cd - Cu - Fe EDL. Fixed concentra- tion solution sprayed for each element. Atomic- fluorescence scales not comparable between ele- ments. EDLs operated in the 3/4h cylindrical (Broida) cavity are equally sensitive to temperature changes, but in the usual unthermostated mode heating is provided internally by the exciting microwave field, rather than by a controlled external flow of air.However, use of the micro- wave field to heat the plasma as well as to excite it is inefficient, and can considerably reduce operating reliability.Lamp ageing can result in varying efficiency of microwave absorption into the plasma, with corresponding variation in lamp temperature and hence radiant output. Some measure of design control is possible with thermostated muti-element EDLs by proper choice of fill material. Either the pure metal, the iodide or the chloride can be selected, and each will have its own optimum operating temperature, which may differ by 100 K between pure element and chloride.The choice of fill gas and fill pressure involves a compromise between maximum intensity and lamp lifetime. Helium at 5 t o n provides 3 x the radiant output of lamps prepared with argon at 0-5 torr, but the lifetime is greatly reduced (150 h with helium compared with approximately 1000 h with argon). Argon at 0-5 torr is therefore usually selected.The tunable dye laser can be either flashlamp-pumped internally or pumped externally with a nitrogen laser. Peak powers of 5-15 kW can be obtained at 0-15 Hz with pulse durations up to 500 ns. The wavelength range 350-680 nm can be covered with suitable dye cell interchange. Frequency doubling provides peak powers up to 600W between 265 and 340 nm.. This energy can be concentrated into 1.2 x nm directly, or in a few picometres with a Fabry-P6rot ittalon. In AFS, these output powers may be sufficient, when the laser beam interacts with the atom reservoir, to induce near saturation of the excited state. Under these conditions, the atomic excited state population approaches that of the ground state. Important practical advantages that result from this situation include a very long linear analytical range (5-6 decades) , combined with insensitivity to source fluctuations and freedom from fluorescence quenching effects.This allows use of the nitrous oxide - acetylene flame to reduce interference effects without producing the corresponding loss of signal that normally results from the high quenching effect of the flame.Source scattering can still be a problem, however. Very low detection limits have been obtained in AFS with tunable dye lasers, and they have clear potential in multi-element work once their present high cost has been reduced.140 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc. Analyt. Div. Chem. SOC. In summary, multi-element AFS is a relatively simple instrumental technique that offers an alternative to the inductively coupled radiofrequency plasma torch in multi-element atomic spectroscopy.It is likely that the two techniques will fill complementary roles in the future. The author thanks the Government Chemist for permission to publish this paper. References 1. Browner, R. F., Analyst, 1974, 99, 617. 2. Norris, J .D., and West, T. S., Analyt. Chem., 1973, 45, 226. 3. Malmstadt, H. V., and Cordos, E., Amer. Lab., 1972, 4 (8), 36. 4. Mitchell, D. G., and Johansson, A., Spectrochim. A d a , 1970, 25B, 176. 5. Patel, B. M., Browner, R. F., and Winefordner, J . D., Analyt. Chem., 1972, 44, 2272. 6. Omenetto, N., Fraser, L. M., and Winefordner, J. D., Appl. Spectvosc. Rev., 1973, 7, 79. 7. West, T.S., and Cresser, M. S., Appl. Spectvosc. Rev., 1973, 7, 79. An Assessment of the Inductively Coupled High-frequency Plasma for Simultaneous Multi-element Analysis P. W. J. M. Boumans and F. J. de Boer Philips Research Laboratories, Eindhoven, The Netherlands This paper has two objects : firstly, to present a general assessment of flame sources and high- frequency (HF) plasmas for multi-element analysis of solutions, and secondly, to report on the progress of the work in this field performed in the authors’ laboratory.For comparison, some appraisals of d.c. arc emission spectrometry and flame and furnace atomic-absorption spectrometry (AAS) are included. Assessments of the potentials of HF plasmas have been made on various occasions during recent years.1-l2 Greenfield, for example, presented a paper on this topic during the SAC Centenary Celebrations in July, 1974.s He showed clearly that the HF plasma, as developed in his laboratory, is a powerful tool for the multi-element analysis of solutions.Greenfield thought it superfluous, therefore, to dwell any longer on the potential of the HF plasma. However, in a total appraisal, “potential” embraces more than the analytical performance alone and we therefore thought it necessary to return again to its potential.The crucial point for a total appraisal of the HF plasma is whether a proper balance can be achieved between purely analytical characteristics on the one hand, and factors such as ease of operation and cost on the other. Strangely, it is generally not fully appreciated what is a proper balance between analytical characteristics, ease of operation and cost.A possible reason is that most analysts have been “spoilt” by AAS and have lost the proper perspectives. Actually, one does not realise sufficiently the merits and advantages that a truly multi-element technique possesses and that these merits and advantages will have to be “paid” for.An Assessment of Four Analytical Techniques In order to facilitate an unbiased appreciation of this question, we shall make a com- (i) (ii) flame atomic-absorption spectrometry (flame AAS) ; (iii) graphite cuvette atomic-absorption spectrometry (furnace AAS) ; and (iv) optical emission spectrometry using the inductively coupled high-frequency plasma The characteristics upon which an appraisal will be based are listed in the left-hand column of Fig.1. Appraisals of the separate items are expressed by the position and shading of blocks for each method and characteristic. A white block indicates a positive and a black one a negative judgement. The further a block is displaced t b the right from the vertical axis the more positive the characteristic is judged to be.Siinplicity parative assessment of four important spectroscopic analysis methods (Fig. l ) , viz. : classical optical emission spectrometry using the d.c. arc (d.c. arc OES) ; (ICP OES) . Simplicity denotes the over-all ease of operation, the lack of skill required from the operator, o t rMay, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Simplicity cost Precision Multi-element capability Interferences Solid state Stable compound formation I onisat ion Detection limits Relative Abso I Ute Sample size Dynamic range 141 P _....g ..... .... Fig. 1. Comparative assessment of d.c. arc optical emission spectrometry (d.c. arc OES), flame atomic-absorption spectrometry (flame AAS) , furnace atomic-absorption spectrometry (furnace AAS) and inductively coupled high-frequency plasma optical emission spectrometry (ICP OES).The shading of the boxes is explained in the text. cost Cost is taken to cover the apparatus cost and cost of operation, without refinements such as specifications in terms of cost per analyte element. Simplicity and low cost in this sense are outstanding features of AAS techniques, but receive a negative judgement for the d.c.arc. Recent developments of the ICP indicate that for this new technique simplicity and cost are coming into the “white zone,” which is ex- tremely important as almost all other characteristics obtain a favourably positive appraisal. Precision The precision (reproducibility) of ICP OES is of the order of 1-2 per cent. relative standard deviation at concentration levels above five to ten times the detection limits. This precision is comparable with that of flame AAS, better than or equal to that of furnace AAS and far better than that of d.c.arc OES. Multi-element capability Multi-element capability denotes the capability of determining a large variety of elements, in principle any group of elements selected at random from the Periodic Table, simultaneously in the same sample.Both the d.c. arc and the ICP have the excellent multi-element capability inherent in emission techniques using a high-temperature source. The lack of multi-element capability in AAS techniques, on the other hand, is a typical feature of AAS and is one of the greatest limitations of this popular method. Interferences The extent of inter-element interferences is a measure of the accuracy that can be attained; for that reason, accuracy is not explicitly considered here.The term “interferences” has been split into three major categories. These are defined as interferences that are related to the physical properties of solid samples, such as crystal structure and grain size. They also include interferences that are caused by interactions between a solid sample and the sample holder, such as the supporting electrode of a d.c.arc and a graphite furnace. Solid-state interferences manifest themselves strongly in d.c. arc analysis (of solids) and are eliminated in solution techniques, such as flame AAS and ICP OES. This type of inter- Solid-state interferences.142 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc.Analyt. Div. Chem. SOC. ference may occur in furnace AAS techniques, because these techniques are apparently only solution techniques. Usually, the solvent is rapidly evaporated and then interaction between the solid sample and the furnace material (graphite) occurs, so that one can encounter inter- ference problems similar to those encountered in a d.c.arc. These are defined as interference effects due to the composition of the sample and occur in the plasma as a result of any of the processes (solute vaporisation, volatilisation, dissociation) that govern the decomposition of the injected aerosol into free atoms. This type of interference effect can be neglected in high-temperature plasmas such as the d.c. arc and ICP. These interferences may be severe, however, in low-temperature atomi- sation cells, such as flames and furnaces. Ionisation interferences.These are defined as interference effects caused by shifts in ionisation equilibria in the gaseous state. This type of interference may be large in a d.c. arc (a reason for the use of spectroscopic buffers) and is frequently negligible in flames and furnaces.The ICP occupies a special position and differs from the d.c. arc in that the operating parameters can be chosen so that ionisation interference is small, even without application of a spectroscopic buffer. Detection limits This item has been subdivided so as to cover relative or concentration detection limits and absolute or mass detection limits separately. Both the d.c.arc and the ICP give favourable relative detection limits. Those attained in the ICP, when related to the matrix present in the solution, are even one or two orders of magnitude better than those reached in the d.c. arc. Flame AAS is no longer competitive with the ICP, whereas furnace AAS is competitive only for relatively volatile elements that do not form stable compounds.Here, however, we must state that for the ICP the absolute detection limits are unsatisfactory only if con- tinuous nebulisation is employed. These detection limits can be appreciably improved by the use of special injection techniques, for example, tantalum filament e ~ a p o r a t i o n ~ , ~ ~ ; this is indicated by shaded blocks. Sample size Sample size is defined as the volume of a liquid sample or the mass of a solid or dissolved sample normally required for an analysis.Here, furnace AAS is the most satisfactory. However, when the tantalum filament technique is combined with the ICP, very small samples can be analysed, so both techniques become competitive. Dynamic range The term “dynamic range” is used here as an indication of the concentration ranges that can be covered in simultaneous multi-element analysis, i.e., without using separate samples for the various elements and concentration ranges of interest.The dynamic range is inherently far more favourable for emission techniques, because o;e has a large variety of spectral lines (atom and ion lines with different excitation energies and transition probabilities) available.Even with resonance lines, the linear region of the analytical curves extends from the detection limit to concentrations that are four to six orders of magnitude above the detection limit. Interferences due to stable compound formation. In Fig. 1 this is indicated by the cross-hatched blocks. Similar restrictions have to be made for the absolute detection limits. A noteworthy feature of the ICP is the large linear range of the analytical curves. Flame-emission Spectrometry Flame-emission spectrometry (flame OES) was not included in Fig.1 because the situation for this techniques does not differ appreciably from that shown for flame AAS, even if a high-temperature flame, e.g., an -acetylene - nitrous oxide flame, is employed. Admittedly, as flame OES is an emission technique, it has far better prospects than AAS techniques for multi-element analysis.The main limitations of a flame source with a temperature up to 3000 K for OES are the following : (a) Spectral lines with wavelengths below about 350 nm are insufficiently excited. (b) The degree of atomisation of elements that form stable compounds is low, which hasMay, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 143 unfavourable effects on the detection power, the sensitivity, and interferences due to stable compound formation.(c) Excitation of lines other than resonance lines is inadequate. (d) Spectral interferences from band spectra may be troublesome. These limitations essentially imply that one would have to select samples that fit the analysis technique, which is not possible for the analyst.Inductively Coupled High-frequency Plasma perature above 5000 K. It can be shown4 that an excitation source for multi-element analysis should have a tem- (a) A high degree of atomisation for all elements, so that favourable conditions exist for achieving high detection power, high sensitivity and adequate suppression of inter- ferences due to stable compound formation.A large variety of atom and ion lines is excited so that suitable analysis lines can often be found for the various concentration ranges to be covered in a multi-element analysis. Inter-element effects in the plasma are predominantly caused by ionisation inter- ference; when no other means are available (such as the proper choice of the operating parameters with an ICP), this type of interference can be coped with adequately by the use of a spectroscopic buffer.Such a source provides for the following: ( b ) (c) Toroidal shape of I C P A drawback of high-temperature plasmas is that it is difficult to introduce aerosols effectively and reproducibly into such plasmas. This difficulty has been overcome most elegantly in the ICP in that the plasma is given a toroidal shape and the aerosol is injected via a “tunnel” of relatively low temperature.This possibility was recognised and explored by Greenfield at the very beginning of his studies of high-frequency ~1asrnas.l~ The toroidal shape of the plasma is preserved in most ICPs that have since been developed for analytical purposes. In other respects, however, rather drastic modifications have been made.Low-power I C P The most striking modification is the reduction of the power at which the ICP is operated. Reduction in power entails a reduction in the size and price of the equipment and also results, in lower operating costs, while an analytical performance nearly similar to that of high-power ICPs could be maintained.Table I summarises some characteristics of the low-power generator used in our labora- tory.1-3 The parameters of the applied Colpitts circuit have been chosen so that the power transferred to the plasma is automatically stabilised within the working range of the instru- ment. This implies that no special precautions have to be taken for igniting the plasma and that changes in the impedance of the plasma caused by the introduction of aerosols do not affect the power transfer, only the frequency changes slightly. TABLE I CHARACTERISTICS OF HF GENERATOR (PHILIPS PROTOTYPE) USED FOR ICY, AFTER BOUMANS AND DE BOER1-3 Characteristic Condition Colpitt oscillator . ... .. . . Automatically stabilised Frequency . . .. .. .. . . 50 MHz Anode current of oscillator tube .. . . 400-600mA power transfer t o plasma Power output to plasma . . . . . . 0’4-1.0 kW Maximum power input to generator . . 2.3 kW The power coupled into the plasma can be varied within the range indicated in Table I by changing the anode current of the oscillator tube by varying the voltage applied to the power supply.144 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc.Analyt. Div. Chem. SOC. The relationship between the power put into the plasma and the anode current of the oscil- lator tube has been determined calorimetrically. This relationship is a linear function whose parameters depend on the dimensions of the load coil and the plasma tube configuration. Given this assembly, the anode current can be calibrated in terms of the power output.A - 20 cm Plasma tube conjguration and gas $ows The flow-rates of the gas streams are also indicated. A low-power ICP can be maintained with only two gas flows, namely the coolant and carrier gas flows. Gas consumption (argon) is low compared with that of high-power ICPs. For example, Greenfield's high-power ICP (4-6 kW coupled into the plasma) employs three gas flows and consumes 20-70 1 min-l of nitrogen as coolant gas, 10-35 1 min-l of argon as plasma gas and 2-3 1 min-l of argon as carrier Fig.2 is a schematic diagram of the plasma tube configuration. 1 Plasma tube assemb nduction coil Coolant and (argon: 19 I min-.' I c-- stabilisation gas Carrier gas (argon : 1.3 I min-' 1 t with dry aerosol Fig. 2. Schematic diagram of plasma tube assembly and induction coil used for low-power ICP.Nebuliser In our ICP arrangement, we employ an ultrasonic nebuliser combined with a de-solvation apparatus. The principal characteristics of this assembly are the following : solution uptake rate, 3.0 ml min-l; efficiency, 12 per cent.; injection rate of dry aerosol into plasma (in terms of original sample solution), 0-36 ml min-l; stability, 1-2 per cent. (expressed as relative standard deviation of net line intensities emitted from the plasma and integrated over 15-s periods during several hours of continuous operation).In view of the low power at which our ICP is operated (0.7 kW under compromise con- ditions for multi-element analysis ; see below), we have hitherto preferred a nebuliser assembly with de-solvation facilities so as to avoid injection of large amounts of water vapour into the plasma.We found that the plasma also remains stable when a wet aerosol is introduced, however. Under those conditions, interference effects were found to be far more serious than with dried aerosols. On the other hand, de-solvation sometimes gives rise to chemical( ?) interference effects in the de-solvation apparatus whose nature must be established by de- tailed studies.Principal experimental parameters of ICP after Boumans and de Boer meters dominate the detection limits and the extent of ionisation interferences, viz. : Experience has shown that in our ICP arrangement essentially three experimental para- (i) (ii) the flow-rate of the carrier gas; (iii) the observation height (defined as the distance between the centre of a 5-mm high Variation of these parameters may have a large influence on both the detection limits of the individual elements and the extent of ionisation interference effects.We established compromise conditions for multi-element analysis under which excellent detection limits for a large number of elements were attained and at the same time satisfactory suppression of the power output to the plasma; observation zone and the top of the work coil).May, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 145 ionisation interference was achieved.These conditions for our apparatus are power, 0.7 kW; carrier gas flow-rate, 1.3 1 min-l; and observation height, 15 mm. Detection limits The detection limits (24 of 32 representative elements determined in pure aqueous solu- tions (0.5 M hydrochloric acid) under compromise conditions for multi-element analysis are listed in Table 11, together with the detection limits for single-element optimisation that we published previously,1,2 and detection limits for compromise conditions published recently by another group of workers.’ Only those elements which were considered in both labora- tories are entered into the table.The values of the “single-element detection limits” are included chiefly in order to provide a link with our earlier workl,2; they should not be treated too rigorously, as single-element optimisation involved the variation of only two parameters, namely carrier gas flow-rate and observation height, whereas the power was TABLE I1 DETECTION LIMITS IN THE LOW-POWER ICP ACHIEVED UNDER COMPROMISE CONDITIONS FOR MULTI-ELEMENT ANALYSIS IN TWO LABORATORIES AND CORRECTED SINGLE-ELEMENT VALUES PUBLISHED PREVIOUSLY BY BOUMANS AND DE BOER The listed values are the concentrations that produce a signal twice as large as the standard deviation of the fluctuations in the background intensity; the values are for pure aqueous solutions (0.5 M hydrochloric acid).The spectrometric conditions used by Boumans and de Boer are specified in Table 111; those used by Fassel and Kniseley were not precisely specified but can be assumed not to be essentially different. We cannot offer an explanation for the discrepancies between the two sets of detection limits other than the two ICP arrangements (including the sample introduction devices) being different.3 A difference in sample injection rate (about 0.15 ml min-l in the Fassel and Kniseley and about 0-35 ml min-1 in the Boumans and de Boer ICP3) could account for a factor of 2 ; there could also be some influence of the integration time (see Table 111), which was not mentioned by Fassel and Kniseley.7 For further comments, see ref.3. Element A1 As B Ba Be Ca Cd Ce Cr cu Fe Grt Ge La Mn Mo Na Nb Ni P Pb Pd Sn Sr Ti V w Y Yb Zn Zr Mg Detection limitlng ml-l f A \ Compromise conditions - , Single-element optimisation, Boumans and Fassel and Boumans and de B0er~9~ Knisele y de Boer1.* 0.2 2 0.08 6 40 200 0.1 5 40 0.01 0.1 0.02 0-003 0-5 0.1 0-0001 0-07 0.01 0.2 2 2 0.4 7 1 0.1 1 0.08 0.06 I 0.08 0.09 6 0.1 0.6 14 0.2 0-5 150 3 0.1 3 0.2 0.003 0.7 0-03 0.02 0-7 0.04 0-5 5 0.1 0.02 0.2 0.4 0.2 10 0.2 6 0.1 15 40 30 2 8 1 2 7 0.8 3 300 10 0-003 0-02 - 0.03 3 0.1 0.06 6 0.08 0.8 2 0.7 0.04 0.2 0.04 0.02 0.9 0.03 0.1 2 12 0.06 5 0.4 -146 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc.Analyt. Div. Chem. SOC. kept constant at 04-06 kW. We did not think it relevant to determine the “single-element detection limits” more precisely now, because the ICP technique is primarily intended for multi-element and not for single-element analysis. The single-element values in Table I1 differ from the published values owing to a correction that was applied in order to allow for an improvement in the nebuliser stability.This im- provement resulted in greater stability of the background intensity.The present per- formance yields an over-all relative standard deviation for the background fluctuations (apl) of 0.01 instead of the varying values for the individual spectral lines published earlier.192 The new “single-element detection limits” were calculated on the basis of a noise level (20rel) of 0.02 and the line to background ratios listed in the previous publications.lS2 Other correc- tions were not applied, although the improvement of the nebuliser also led to a higher sample injection rate into the plasma and thus to higher sensitivity and better detection limits.The multi-element detection limits attained under the compromise conditions and listed in Table I1 reflect the present state of the art in our laboratory for the spectrometric conditions summarised in Table 111.The results in Table I1 show that continued investigations led to a multi-element detection power that compares favourably with both the “single-element detection power” we attained about 3 years ago and the multi-element detection power ob- tained by Fassel and Kniseley.’ This is also illustrated by the cumulative distributions in Table IV.TABLE I11 DE BOER GIVEN IX TABLE I1 WERE ATTAINED SPECTROMETRIC CONDITIONS UNDER WHICH THE DETECTION LIMITS AFTER BOUMANS AND Characteristic Condition Spectrometer Grating Blaze Order Slits Photomultiplier Amplifier Integrator Integration time 1-m Czerny-Turner monochromator 1200 rulings per millimetre 500 nm I or I1 25 pm EM1 9601B Lock-in, 400 Hz Digital, coupled to re-transmitting 15 s potentiometer of recorder Comparison.with AAS. Fassel and Kniseley’ determined the detection limits of 65 ele- ments (including those listed in Table 11) with the ICP developed at Iowa State University and compared them with those of flame AAS. A striking superiority of the ICP OES values was found, so that no further comment is required.We need only recall here our remarks with regard to detection limits made in our assessment of the four analytical techniques considered at the beginning of this paper (Fig. 1). TABLE IV CUMULATIVE DISTRIBUTION OF DETECTION LIMITS OF 32 ELEMENTS OBTAINED I N LOW-POWER I C P S Number of elements having a detection limit in the stated range Compromise conditions for multi-element analysis r A > Rangelng ml-l Boumans and de Boer Fassel and Kniseley* go-01 5 0 go-1 18 3 Q1 27 11 g 10 31 27 > 10 1 5 Total number of elements 32 32 Single-element optimisation, Boumans and de Boer 0 15 23 26 4 30 * These authors determined the detection limits of 61 elements and found 41 values below 10 ng ml-1 and 56 values below 100 ng ml-l.May, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 147 Comparison with other excitation sources. How does the detection power of our ICP com- pare with that of other high-temperature excitation sources such as the capacitatively coupled microwave plasma (CMP) and the d.c.plasma jet? A comparative study between a nitrogen CMP and our ICP is being undertaken and results will be published sh0rt1y.l~ From the experiments conducted hitherto, it has already become evident that the ICP shows multi-element detection limits that are sometimes equal to but often one to three orders of magnitude superior to those attained in the CMP, the largest differences being found for elements with sensitive ion lines.Experience with a d.c. plasma jet was very disappointing. In addition to other drawbacks we found that the detection power lagged, in general, three orders of magnitude behind that of the ICP.It can be seen from Table I1 that most of the detection limits achieved with our ICP under compromise conditions for multi- element analysis are in the range 0-01-1 ng ml-l. This range applies to pure aqueous solutions (0.05 M hydrochloric acid) but is only slightly affected when a “matrix” is added.The presence of a matrix leads to some enhancement of the background intensity without a concomitant increase in line intensities. The net effect on the detection limits is a deterio- ration not greater than a factor of 1-5-2 under the conditions adopted in our work, i.e., when the matrix concentration is kept below 0.1-0.5 per cent. m/V. Such an upper limit is set by the nebuliser - de-solvation assembly and not by the plasma itself.The precise value of this limit depends on the type of matrix. Taking 0-2 per cent. as the commonest value and expressing the detection limits with respect to the dissolved matrix, we find a range between 0.005 and 0.5 pg g-1 (p.p.m.). If finally we take into account that the presence of a matrix causes spectral interferences and tends to rule out some of the most sensitive analysis lines, it does not seem an exaggeration to state that the ICP enables the analyst, in general, to perform a multi-element analysis with detection limits in the range 0.1-10 t ~ g g-l with respect to the matrix and 0-1-10ngml-l with respect to the solution. This detection power is better than that of a d.c.arc if it is also operated under compromise conditions for multi- element analy~is.1~ I t is sometimes stated that a detection power as high as that of the ICP is seldom required in “normal” analytical practice. However, it must be realised that concentration determination in the vicinity of the detection limit (i.e., at concentrations not exceeding the detection limit by at least one order of magnitude) are unreliable, even if the method has a high intrinsic precision.Therefore, the high detection power of the ICP implies not only that “sub-normal” con- centrations can be detected, but also that “normal” concentrations can be determined, as they will fall in a range where the inherent precision of the method can be fully exploited. This characteristic can be used to advantage in both trace analysis and the determination of major and minor constituents (in micro-samples). Detection power of I C P under true analysis conditions.Advantages of high detection power. Interferences It is also very likely that interferences due to stable compound formation in the plasma do not occur.697 This is due to the high temperature of the plasma, the inert atmosphere and the relatively long time (a few milliseconds) that a sample takes to travel through the “tunnel” in the toroid before it reaches the observation zone so that dissociation is ~omplete.*,~,~ The interferences that we observed are linked with processes that occur in the de-solvation apparatus (which may affect the over-all efficiency of the nebuliser - de-solvation apparatus assembly) and to “ionisation interferences” in the plasma.By the term “ionisation inter- ferences” we denote those effects which show clear trends with the ionisation potential of both the interfering element (matrix) and the test element (analyte). In the experiments conducted hitherto, we have not yet made an approach in which “de- solvation interferences” could be separated from “ionisation interferences.” Such a separa- tion was not important in our initial studies, as it turned out that the over-all effects were governed by the three experimental parameters mentioned in connection with the selection of compromise conditions for multi-element analysis, viz., power, carrier gas flow-rate and observation height.3 As all of these parameters refer to conditions that prevail in (the observation zone of) the plasma, it was reasonable to attribute the observed over-all effects As a solution technique, ICP OES eliminates solid-state interference effects.148 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc.Analyt. Div. Chem. SOC. chiefly to “ionisation interferences,” the more so as some trends within the ionisation poten- tials of the elements involved were recognised.3 Once we had found compromise conditions and reduced the over-all interference effects to the “10 per cent.level” (i.e., enhancement or depression effects of 0-20 per cent.), it became apparent that a precise classification of the effects will require the separation of de-solvation interferences from ionisation interferences. When we varied the three experimental parameters over rather wide ranges (power, 0.4- 1.0 kW; carrier gas flow-rate, 1.1-1-7 1 min-l; observation height, 15-25 mm), we observed that the detection limits and the interference effects were affected in opposite directions, i.e., we found rather large matrix effects (up to a factor of 5) under conditions that gave extremely low detection limits, and conversely, a poorer detection power under conditions such that interference effects were small.3 A systematic investigation of these trends for some representative spectral lines led to compromise conditions for multi-element analysis under which excellent detection power proved to be compatible with a tolerable degree of interference.As an illustration we mention the effects of potassium (1 mg ml-1) and caesium (2 mg ml-1) on some spectral line intensities. The intensities of atom lines of lithium and strontium were enhanced by 10-20 per cent.while an enhancement or depression effect less than 10 per cent. was found for atom lines of aluminium, cadmium, manganese, vanadium and titan- ium and for ion lines of lanthanum, strontium, titanium and zirconium. A striking feature is the relative insensitivity of intensities of the spectral lines emitted by singly charged ions for the addition of easily ionised elements. In this respect, the ICP differs largely from excitation sources such as the d.c.arc.16J7 This also became apparent when we attempted to explain some of the observed phenomena in terms of effective temperatures, electron concentrations and particle concentrations in the plasma as derived from space-integrated intensities.This approach, although useful for a d.c. arc, ended in a deadlock with the toroidal ICP.3 The chief reason is the large spatial inhomogeneity of this source, which calls for a physical analysis in terms of the spatial distributions of temperature, electron concentration and particle concentration^.^^^^ In addition, possible departures from local thermal equilibrium (LTE), particularly with respect to the ionisation temperature, should be borne in mind.l9 Finally, it must be established whether the second stage of ionisation plays a substantial role.The formation of doubly ionised atoms could be a reason for the peculiar behaviour of the spectral lines emitted by singly charged ions.Whatever refined physical studies will show about the precise nature of the various effects, it has become evident that the operating conditions of an ICP can be adjusted so that inter- ference effects are small in comparison with the effects observed in other excitation sources.3~7~14,16J7 Although our experience has shown that power, carrier gas flow-rate and observation height have a major influence in that they define the order of magnitude of interference effects, some minor factors also have to be considered once compromise conditions have been found and interference has been brought down to the “10 per cent.level.” Such factors are the field of view as defined by the optics and the precise location of the plasma with respect to the optics, and the degree of symmetry of the plasma as defined by the accuracy with which the plasma tubes are centred around their common axis.The importance of reproducibly defining the field of view and ensuring the symmetry of the plasma follows from the observation that interference effects are closely related to changes in the spatial intensity distribution in the plasma.Although these changes, in turn, may be correlated with the ionisation potentials of the elements concerned and the term “ionisation interference” can therefore be defended, the underlying phenomena seem to be more complex than the term suggests, i.e., the effects cannot be simply interpreted in terms of ionisation suppression. To conclude, the low-power ICP we have under development is a promising tool for multi- element analysis, not only in view of its excellent detection power but also owing to its favourable interference characteristics, which, together with the precision of 1-2 per cent., will guarantee a high accuracy of analytical results. Of primary importance for the analyst is that such conditions exist.Examples of applications In order to illustrate the capabilities of our ICP in the analysis of real samples, a few examples of applications are given below. These examples must be regarded chiefly as reconnaissances in the field of applications and not as exhaustively developed analyticalMay, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 149 procedures. The studies were primarily made in order to check some of the conclusions drawn from our systematic studies. This investigation was performed in co- operation with the Central Analytical Laboratory of Estel-Hoogovens, I Jmuiden, The Nether- In this laboratory, inclusions and precipitates in steel are frequently analysed by single-element techniques, usually absorption spectrophotometry.The elements of interest are aluminium, boron, cerium, chromium, manganese, molybdenum, niobium, silicon, titan- ium, vanadium, tungsten and zirconium.Sample solutions are prepared as follows. A 1-g amount of steel is dissolved in hydrochloric acid and the residue (<20 mg) is fused with 2 4 g of sodium pyrosulphate. The melt is dissolved in 100 ml of water, to which hydro- chloric or tartaric acid is sometimes added. Our object was to determine some elements directly in these solutions with the ICP and to compare the results with those obtained by spectrophotometry in the Estel-Hoogovens laboratory.Information about the concentration ranges of interest furnished by steel experts and some preliminary investigations suggested that analytical graphs covering a concentration range between 0.1 and 2.5 pg ml-l would be adequate for all elements, if the original 100-ml sample solutions were diluted 1 + 10 or 1 + 20.We prepared standard solutions for this range with sodium sulphate (7 mg ml-l) and sulphuric acid (0.1 N) so as to circumvent also the small matrix effect that would occur if Dure aaueous solutions were used as standards. Analysis of inclusions and precipitates in steel.Fig. 3 shows some of the perfectly linear inalytical graphs, which that are two to five orders of magnitude above the detection limits of (cf., Table 11). cover concentrations the analyte elements Re1 at ive i nten si ty Fig. 3. Examples of analytical graphs used for deter- mining various elements in steel precipitates with an ICP. The graphs were obtained without reference element(s).Owing to the high stability of the ICP, the use of reference elements is not required when short-term calibrations covering a period of several hours to one day are performed. We call it a multi-element analysis, as all elements were determined in one solution, although not simultaneously. For research work, we prefer a single-channel but flexible monochromator (Table 111) rather than a multi-channel spectrometer with fixed exit slits.Obviously, the sequential mode of measurement applied here is a limitation of the spectrometric apparatus only and does not affect the intrinsic multi-element character of ICP OES. Table VI summarises results of vanadium determinations in real samples obtained by ICP OES and spectrophotometry.It also gives the matrix compositions of the various sample and standard solutions. The differences in potassium pyrosulphate concentration are due to the fact that the samples differed from those which we had expected so that various dilutions of the original sample solutions were required in order to bring the analyte con- centrations into the working range of the standard solutions.After all, the differences in matrix composition did not adversely affect the results ; the satisfactory agreement between the two sets of results in Table VI in fact demonstrates the extent to which matrix effects Table V gives the results of a multi-element analysis of a synthetic solution.150 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS Proc. Analyt.Div. Chem. SOC. are suppressed in the ICP. Results similar to those achieved for vanadium were also obtained for titanium and niobium. TABLE V MULTI-ELEMENT ANALYSIS OF A KNOWN SOLUTION OF ELEMENTS TO BE DETERMINED IN STEEL PRECIPITATES Matrix: I<,SO, (7 mg ml-l), Fe (10 pg ml-l), H,SO, (0.1 N). Concentrationlpg ml-l Element Added Found Difference, per cent. A1 0.80 0.82 + 2.5 Ce 0-40 0.42 + 5.0 Cr 0.15 0.16 2.0 Mn 0.60 0.62 + 3.3 Ti 0.35 0.35 2.0 W 0.76 0.73 - 2.7 Spectral interferences were studied during the preliminary work.It was found that the most sensitive lines of aluminium, boron, chromium, manganese, molybdenum, silicon, titanium and vanadium can always be used in the analysis of precipitates, even when a large number of the relevant elements are present simultaneously at high concentrations.For cerium, niobium, tungsten and zirconium, however, we found that the analytical lines must be chosen in compliance with the composition of the sample. Criteria for line selection and a simple iterative procedure for correcting for line interference have been developed and correction factors for the various lines adopted have been determined experimentally.20 This application study and related studies made by Fassel and his co-workers indicate that the low-power ICP has good potential for metallurgical analysis and may become a highly useful tool not only for analysing inclusions and precipitates in steel but also for analysing metals and alloys which should serve as standards in spark-emission spectrometry or for which a solution technique is preferred in view of their inhomogeneity.Analysis of surface and efluent waters. The ICP can be used in order to determine toxic elements in surface and effluent waters. If the concentrations to be determined are not extremely low, analyses can be carried out directly on the original sample, i.e., without pre- concent ration. As an example, we can consider results for iron, zinc and lead.Table VII compares results obtained by ICP OES, wet-chemical analysis and X-ray fluorescence spectrometry. The Icp determinations were made directly on the original sample by using a standard addition technique. Corrections were applied for spectral interferences from iron and calcium in the lead determinations. Owing to these corrections and the high background in the visible part of the spectrum caused by the presence of large amounts of calcium salts, the lowest concen- tration at which lead can be reliably determined is about 10ngml-1.When lower con- centrations are to be measured, separation of lead from the matrix is required. The large variations in the composition of the samples may give rise to varying degrees of spectral interferences, so that the contributions of interfering elements to the intensities of the lines We must point out here a risk involved in using OES for this type of analysis.TABLE VI DETERMINATION OF VANADIUM IN STEEL PRECIPITATES USING ICP OES AND SPECTROPHOTOMETRY f Sample a b d e Standard C Matrix in analysed \ r------h 7 Concentration, per cent.solution/mg ml-l ICP OES Spectrophotometry K,SO, Tartaric acid A - 0.059 0-053 1.5 - 0.028 0.027 1.5 - 0.006 0.006 14 20 0-064 0-064 3 0.4 0.057 0.060 3 0-4 - 7 - -May, 1975 SIMULTANEOUS MULTI-ELEMENT TRACE ANALYSIS 151 of the analytes may be different from one sample to another. The mere application of the standard addition technique does not reveal such contributions and may lead to results that are too high.Therefore, the concentrations of possible interfering elements must also be determined in order to provide for checks and corrections. This procedure does not cause any difficulties in ICP OES, however, because of the excellent multi-element capability of this method and the small matrix effects that permit calibrations with simple (aqueous) standard solutions.An apparently weak point of OES is thus perfectly balanced. TABLE VII CONCENTRATIONS (pgml-1) OF IRON, ZINC AND LEAD IN SURFACE AND EFFLUENT WATER AS DETERMINED BY THREE INDEPENDENT METHODS Method r > A ICP OES Various X-ray fluorescence directly in wet-chemical after co-precipita- Sample Anal yte original sample methods tion of analytes Surface water Fe Zn Pb Effluent water Fe Zn Pb 1.10 1.04* 1.05 0.24 0.23t 0.23 0.035 0.030$ 0.045 6.5 6*0* 7.0 0.020 0.045 0.045: 24 25 21t * Standard spectrophotometric method after destruction of possible iron complexes.t Flame AAS (acetylene - air flame) directly on original sample. $ Furnace AAS after selective separation of the analyte. Conclusions We have shown some of the perspectives and potential of the low-power ICP for multi- element analysis.Many other examples could be added, because in principle ICP OES can be applied to any type of multi-element analysis where either the sample is in the form of a solution or dissolution of a solid sample is possible or even preferable. Therefore, the use- fulness of the ICP for the analysis of biological fluids, surface and effluent waters, soil extracts, plant ashes, geological materials, slags, ores, ceramics, cements, metals, alloys and chemicals is evident, especially as the successful application of a high-power ICP for the analysis of these types of samples has been well documented already by Greenfield and ~o-workers.*~~ Of particular interest is the large variety of accessible elements, which include those which tend to form stable compounds.Thus, the ideal that asolution technique should embrace any group of elements selected at random from the Periodic Table is approached to the extent that about 70 elements have come within the reach of such a technique. This means that ICP OES is an outstanding method not only for accurate routine deter- minations of a few elements, say four to ten, as commonly required, in a large variety of materials, but also for general analysis of solutions.General analysis can be extended to solids in so far as dissolution does not cause any problems of contamination or losses. Owing to the small interference effects, general analysis using ICP OES will be far more accurate than that using d.c. arc OES. Calibration will be simple as standards of pure aqueous solutions can be employed and, owing to the large linear range of the analytical graphs, only a few standards are required.The actual work involved in setting up a system for general analysis using ICP OES is to build up a “quantitative catalogue of spectral interferences.” The high stability in the spectral output of the ICP will not only facilitate this work, but also give the catalogue a far wider scope than the tables that spectroscopists are still bound to rely upon for checking and correcting for spectral interferences.In addition, the use of completely automatic systems for the quantitative evaluation of photographically recorded spectra, such as described by Witmer et aZ.21 will appreciably reduce the amount of work involved.If one considers Fig. 1 again, but now with the detailed discussion of the ICP as a back- ground, it will be evident that the development of the ICP is giving optical emission spectro- metry new impact. This renaissance is badly needed in order to make this multi-element152 AAS IN THE STEEL INDUSTRY Proc. Analyt. Div. Chem. SOC. analysis technique acceptable for the “ordinary” analyst. Much has been achieved already in that the bulky appearance of HF apparatus has been overcome with the development of the low-power ICP. Yet it seems necessary to move the first two blocks in Fig. 1 further into the “white field.” This can be achieved by both moving the blocks to the right and shifting the “axis of acceptance” to the left ; in other words, both equipment and attitudes should be developed in order to achieve a balance between costs and profits in simultaneous multi-element analysis of solutions by ICP OES more quickly. Also, much has been gained in simplicity of operation. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. References Boumans, P. W. J. M., and de Boer, F. J., Spectrochim. Acta, 1972, 27B, 391. Boumans, P. W. J. M., de Boer, F. J., and de Ruiter, J. W., Philips Tech. Rev., 1973, 33, 50. Boumans, P. W. J. M., and de Boer, F. J., Spectrochim. Acta, Part B, in the press. Boumans, P. W. J. M., Philips Tech. Rev., 1974, 34, 305. Dickinson, G. W., and Fassel, V. A., Analyt. Chem., 1969, 41, 1021. Fassel, V. A. , “Proceedings of the 16th Colloquium Spectroscopicum Internationale, Heidelberg, 1971, Plenary Lectures and Reports,” Adam Hilger, London, 1972, p. 63. Fassel, V. A., and Kniseley, R. N., Analyt. Chem., 1974, 46, lllOA and 1155A. Greenfield, S., paper presented at the SAC Centenary Celebrations, London, July, 1974. Greenfield, S., Jones, I. Ll., McGeachin, H. McD., and Smith, P. B., Analytica Chim. Acta, 1975, Souilliart, J. C., and Robin, J . P., Analusis, 1972, 1, 427. Nixon, R. H., Fassel, V. A., and Kniseley, R. N., Analyt. Chem., 1974, 46, 210. Scott, R. H., Fassel, V. A., Kniseley, R. N., and Nixon, D. E., Analyt. Chem., 1974, 46, 7 5 . Greenfield, S., Jones, I. L1. and Berry, C. T., U.S. Pat. 3,467,471, September, 1969; BY. Pat. Boumans, P. W. J. M., Dahmen, 17. J., de Boer, F. J.. Holzel, H., and Meier, A., Spectvochim. Acta, Knippenberg, W. F., Philips Tech. Rev., 1974, 34, 298. Boumans, P. W. J. M., “Theory of Spectrochemical Excitation,” Adam Hilger, London, 1966. Boumans, P. W. J. M., i n Grove, E. L., Editor, “Analytical Emission Spectroscopy,” Marcel Dekker, Kornblum, G. R., and de Galan, L., Spectrochim. Acta, 1974, 29B, 249. Mermet, J. M., Spectrochim. Acta, Part B, in the press. Boumans, P. W. J. M., and de Boer, F. J., paper presented a t “10 Spektrometertagung,” The Hague, Witmer, A. W., Jansen, J. A. J., van Gool, G. H., and Brouwer G., Philips Tech. Rev., 1974, 34, 322. 74, 225. 1,109,602, April, 1968. Part B, to be published. New York, 1972, Part 2, Chapter 6. May, 1974.

ISSN:0306-1396    

DOI:10.1039/AD9751200138

出版商:RSC    

年代:1975

数据来源: RSC

摘要:

152 AAS IN THE STEEL INDUSTRY Proc. Analyt. Div. Chem. SOC. Atomic-absorption Spectrophotometry in the Steel Industry The following is a summary of the paper presented at the Joint Meetjng of the North East Region with the Modern Methods of Analysis Group of the Sheffield Metallurgical and En- gineering Association held on December loth, 1974, and reported in the January issue of Proceedings (p.5). Further Applications of Atomic-absorption Spectrophotometry in the Steel Industry T. S. Harrison Group Chemical Laboratories, BritisJz Steel Covporation, Scunthovpe Group, P.O. Box No. 1, Scunthorpe, Lincolnshire Developments previously reported in a lecture to the S.M.E.A. Group in March, 1972, were briefly summarised. Procedures developed for iron and steel, oxide and ancillary materials had been written up in loose-leaf book form for circulation within the industry and also published separately in a technical journal.May, 1975 AAS IN THE STEEL INDUSTRY 153 While the methods for iron and steel were primarily intended for the plain and low-alloy material normally encountered in the Scunthorpe laboratories, they had been extended in some instances to highly alloyed steels but with necessary modifications to the flame con- ditions. In the determination of cobalt in stainless-steels interferences, mainly by titanium and vanadium, were evident and the reproducibility was poor in a fuel-rich air - acetylene flame.No interferences were observed in a lean flame and standards showed good agreement with certificate values.Similarly, the method for chromium, when tested in several laboratories on a co-operative basis, showed interferences by titanium, vanadium, molybdenum and aluminium and varia- tions in the richer flames. These difficulties were largely overcome, and improved accuracy in standards was obtained, by use of a lean flame, with a 2-3 mm red “feather.” On the other hand, a luminous flame, in which the background absorption of iron(II1) chloride was least, was preferred in a procedure developed for the determination of tellurium within the range 0-0.080 per cent. in lead-bearing, free-cutting steels.Lead did not interfere and good recoveries of tellurium added to stainless steel were reported. Application of atomic-absorption spectrophotometry to the determination of titanium in steel has been restricted owing to lack of sensitivity, interferences and inability to retain the metal in solution.However, decomposition using hydrochloric acid with nitric acid as oxidant, coupled with fusion of the residue with sodium carbonate - boric acid and extraction in the main solution, gave a satisfactory solution but enhancement of titanium absorption by nickel, chromium, molybdenum and aluminium and depression by copper and cobalt, at the higher levels in each instance, were observed.Comparison of lanthanum and aluminium chlorides as suppressant indicated a preference for aluminium, at an optimum concentration of 500 p.p.m. Subsequent tests on synthetic and standard steels and iron showed the elimination of interferences, except at levels of aluminium above 1 per cent., and agreement with standard values and reproducibility in the application of the recommended method, which has a range of 0-0.80 per cent.of titanium. Current photometric and atomic-absorption spectrophotometric procedures for aluminium in steel lack the desired sensitivity at levels below 0.005 per cent. of aluminium unless amodern, sophisticated instrument for atomic-absorption spectrophotometry is available.The alter- native is to extract the iron with an organic solvent, e.g., isobutyl acetate, from 5 g of sample and to concentrate the residual aqueous phase for spraying. An existing procedure has been examined and modified as follows: (i), more detailed instructions are given for the extraction process, to ensure reproducible conditions for an acceptable level of residual iron; (ii), the acid extract is evaporated to dryness and the residue dissolved in a measured amount of hydrochloric acid in order to reduce the acidity and to give closer control; (iii), nitric acid is added to destroy organic matter; (iv), further addition of iron following the extraction is unnecessary for the suppression of the ionisation of aluminium in the presence of the flux to attain the optimum absorbance and is omitted; and (v), a 3 + 1 mixture of sodium car- bonate and boric acid is preferred to potassium hydrogen sulphate as the flux for insoluble aluminium, the readily ionisable alkali metal suppressing the ionisation of aluminium.Revised detailed procedures have been developed and applied for acid-soluble, acid-in- soluble and total aluminium, recovery tests on synthetic solutions and accuracies and repro- ducibilities on standard steels being very satisfactory.An alternative technique recently introduced at the Hoesch Steelworks, Dortmund, West Germany is also valuable for determining aluminium and other metals at low levels in steel. The rapid injection of 200 pl of sample solution from a micropipette directly into the nebuliser and thence to the flame gives an instantaneous signal measurable on a chart recorder.Com- parison of peak height, however, with the signal produced by conventional spraying, showed no improvement in sensitivity although satisfactory results for aluminium were obtained. When the volume of solution available is inadequate for conventional spraying or when sensitivity may be improved by using a more concentrated sample solution, which would cause burner encrustation in normal practice, then direct injection has definite advantages. The chemical analysis of ferro-alloys is tedious and time consuming as lengthy separations, coupled with gravimetric or volumetric finishes, are involved. These materials contain large percentages of the element to be determined but earlier success with high contents of elements in oxide materials suggested that the rapid technique of atomic absorption could be applied with advantage.The ferroniobium we use contains about 40 per cent. of niobium154 AAS IN THE STEEL INDUSTRY Proc. Analyt. Div. Chem. SOC. and as the sensitivity of this element is low, it was considered that sample dilution would not be great and that the error introduced by dilution would therefore be small.Samples (0.25 g) were therefore dissolved in hydrofluoric acid, with dropwise oxidation by nitric acid, and the solutions then fumed with sulphuric acid in order to remove hydrofluoric acid and so obviate attack on the glass bead in the nebuliser. The niobium salts were then kept in solution by dissolution in hydrochloric acid prior to dilution to volume for spraying.Most routine samples fall within the narrow range of 4045 per cent. of niobium and as only one chemically standardised sample was available a suitable calibration graph was prepared by taking appropriate masses of this sample, covering this range, through the process and plotting absorbance against niobium content in order to obtain a curve that is linear over each 1 per cent.range of niobium. Hence, in effect, two graph points, one on either side of the sample reading, are adequate. A number of samples were then analysed and the results, when compared with those given by the phenylarsonic acid gravimetric method, showed good agreements, adequate for control purposes.The variations, coupled with a reproducibility of k0.60 per cent. of niobium on an individual sample containing 41.0 per cent., were not acceptable, however, for commercial settlement. As the analysis time is reduced by about two thirds, further investigation to improve the performance merits con- sideration. Collaborative work is being carried out on the determination of the major constituents of iron ores by means of atomic-absorption spectrophotometry, initial decomposition with phosphoric acid offering an alternative to fusion as a basis for a composite scheme of analysis.Similarly, for manganese ores, we have derived, for international assessment, a composite scheme for copper, lead, zinc, aluminium, calcium and magnesium, which is based on de- composition with hydrochloric and nitric acids supplemented by fusion with potassium carbonate and boric acid for aluminium, calcium and magnesium.Lanthanum chloride solution is added to suppress any interference with the calcium response. Atomic-absorption spectrophotometry provides a valuable means of standardising materials for the calibration of physical instruments such as emission and X-ray fluorescence spectro- meters and for subsequent reference checks on analysed samples.Besides this regular application in our laboratories, it was used in a joint exercise for the calibration of an X-ray spectrometer for fluorspar-bearing materials. Decomposition with a mixture of nitric, hydrofluoric and perchloric acids, followed by fuming, expelled fluorine and silica ; re-dissolu- tion in hydrochloric acid, dilution and spraying into an air - acetylene flame was the basis for copper, lead, zinc, nickel and iron determinations. For barium, the perchloric acid fuming was replaced by fusion with sodium carbonate and borax, extraction in nitric acid, dilution and spraying into a nitrous oxide - acetylene flame.There were no significant interferences at the levels covered and sodium in the flux prevented the ionisation of barium in the hotter flame. The composite scheme for the analysis of waters and effluents has been extended to include iron and used extensively in connection with new steel plant developments and the control of a biological treatment plant. Similarly, the scheme for the analysis of lubricating oils, based on an initial treatment with dilute nitric acid, is now used to monitor the levels of lead, zinc, barium, calcium, iron, copper, chromium, aluminium and tin in incoming supplies and in used oils in relation to wear. The wear of roller bearings in our mills is also being related to the pick-up of iron in the grease as evaluated by this method. Atomic absorption is making an ever increasing and significant contribution to the labora- tory analytical service, two chemists being engaged full time on routine application. Where- ever practicable it is being extended to the analysis of new materials, particularly to oxides.

ISSN:0306-1396    

DOI:10.1039/AD9751200152

出版商:RSC    

年代:1975

数据来源: RSC

摘要:

May, 1975 ONE HUNDRED YEARS OF ATOMIC SPECTROSCOPY 155 One Hundred Years of Atomic Spectroscopy The following is a summary of the paper presented at a Joint Meeting of the Midlands Region with the Loughborough University of Technology Chemical Society held on March 4th, 1975, and reported in the April issue of Proceedings (p. 108). This is the second of two papers from the Midlands Region relating to the Centenary of the SAC; the first (“One Hundred years of Microchemistry,” by R.Belchcr) appeared in the March issue (p.77). One Hundred Years of Atomic Spectroscopy, 1874-1 974 D. Thorburn Burns Depavtmeizt of Chemistry, Loxghbovough University of Technology, Loughbovough, Leicestershire, L E 11 3T U To appreciate the developments in the period 1874-1974, it is necessary to consider the state of knowledge in optics and spectroscopy prior to the period under review.In 1874, A. J. Angstrom died and the firm of Adam Hilger was set up. The first recorded spectrum is probably that of the rainbow, described in the book of Genesis and elsewhere in the Bible. The first contrived spectrum is that obtained by Newton1 (1666). Marggraf2 (1762) described the yellow flame with sodium nitrate and bluish one with potassium nitrate and used this to differentiate between the two salts.This was possibly the first analytical flame test. The next major step, because of its theoretical implication, was made by Wollaston3 (1802), who described the dark lines crossing the solar spectrum. This effect was later, and apparently independently, observed by Fraunhofer4 (1814) when the dark lines were mapped in detail.The most prominent lines were labelled A to H, and D consisted of two bright lines close together (the sodium D lines). The colours of flames due to salts of strontium, calcium, barium, copper and boron were described and sketched by Herschel5 (1823). However, he did not realise the importance of the elements.Talbot6 (1826) recognised the elements as the source of the lines and thus laid the basis of spectrochemical analysis. He wrote, “This red ray (from the flame of potassium nitrate) appears to possess a definite refrangibility and to be characteristic of the salts of potash, as the yellow ray is of the salts of soda. . . If this should be admitted I would further suggest that whenever the prism shows a homogeneous ray of any colour to exist in a flame, this ray indicates the formation or presence of a definite chemical compound.” The importance of the experiments of Brewster’ (1832) should not be underestimated, despite the poor reception he received at the time.“We have no doubt however that if Dr. Brewster continues to pursue his ingenious investigations, he will by degrees acquire a habit of introduc- ing greater accuracy into his measurements, and what is of still more importance, more mathematical neatness into his calculations.. Using a lamp source, Brewster observed dark lines when nitrous acid gas was interposed between source and prism, and deduced that the Fraunhofer dark lines were caused by gases or vapours surrounding the sun.Herschelg (1840) made first use of photography in spectroscopy. The first spectral atlas was due to an American, Alterlo (1854). This very simple atlas, which describes lines by colour, is to be contrasted with that of Wattsll (1872), which contains wavelengths and approximate intensi- ties and is fully referenced. The Bunsen burner12 (1856) greatly aided the examination of flame spectra; spark spectra were described earlier by Wheatstone13 (1835).Bunsen and Kirchoff14 made considerable improvements to the spectroscope ; early workers used a single lens on one side and thus lost definition of their spectra. Their studies led to the discovery of many new elements, for example caesium and rubidium15; later, other workers found thallium, indium and gallium.Champion, Pellet and Grenierls (1873) developed quantitative flame spectroscopy, using two flames. One flame was saturated with a sodium salt and the other monitored the sample. A blue glass wedge was used in order to attenuate the brighter flame until the intensities of the two flames were equal. Samples were introduced on clockwork-driven platinum wires. A similar sample introduction system was described in a recent American patent.l7 “Reflections on the Decline of Science in England.”18 In addition to learned journals and In the early and mid-nineteenth century, science was popular despite papers such as156 ONE HUNDRED YEARS OF ATOMIC SPECTROSCOPY Proc. Analyt.Div. Chem. SOC. monographs, there were numerous popular annual reviews of science, natural history, the arts, etc.19P From these publications, it is possible to assess the then popular interest in science and in spectra in particular. For example, the “Popular Science Review” for 186g21 contains “The Use of the Spectro- scope in Astronomical Observation’’ by R.A. Proctor, indicating the use of multiple prisms to increase dispersion. A paper by W. A.Miller delivered to the working men of Exeter was on “Experimental Illustrations of the Modes of Determining the Composition of the Sun or other Heavenly Bodies by the Spectrum.” Early solar spectroscopists had their problems, of which one was known as the “irrationality of dispersion”22; lines vary in position owing to the nature of a prism, and apparently similar prisms may behave differently in their dispersion characteristics.The first diffraction grating was due to Rittenhou~e~~ (1786), who did not, however, follow up the discovery. Young24 (1802) used a 500 line per inch grating in the transmission mode and calculated wavelengths using diffraction theory. Early gratings were poor in resolution and dispersion and efficiency. Draper25 (1845) produced reflection gratings, but the major developments were due to Rowlands26 (1883) onwards.Thus the foundations of current methods were qualitatively laid; spectral studies were carefully carried out within the limits of the apparatus and were of popular interest, but the applications, after the excellent start 100 years ago, are relatively recent. A technique that never seemed to lose in interest is that of blowpipe analysis.It was used in quasi-analytical work in the seventeenth century and it was well described by 1741. Major portions of and indeed whole texts, are devoted to blowpipe analysis. As late as 1942 the blowpipe was described as an invaluable in~trument.~~ Browning’s operational manual and catalogue for 187835 is interesting; a two-prism spectro- scope cost j615, while a four-prism instrument, guaranteed to show the nickel line between the two D lines, was l27.Induction coils, &-in spark, were j63 5.5, compared with a 6-in spark coil at E22. For the busy analyst, Lockyer’s revolving spark apparatus with 14 dischargers, costing j66 lOs, was obviously essential. For steady flame spectra, Mitscherlich’s device35 (1862) with capillary delivery via a bundle of platinum wires was the best available at the time.The first successful pneumatic nebuliser was described by Guoy in 1879.36 The early spectroscopic studies have been summarised in texts of the peri0d~~-3~ and recently r e v i e ~ e d . ~ - ~ ~ The initial quantitative aspects of spectrochemical analysis were largely the result of studies by Lockyer, Hartley and de Gramont.Lockyer’s primary interest was astronomy but he made a number of basic observations using spark and flame excitation. He noted that some lines appeared only close to the electrode while others extended throughout the length of the spark and that a flame excited only these “long” lines. Lockyer also noted that possible quantitative analytical techniques could depend on line length, intensity, width and thenumber of lines present as compared with the spectrum of the pure element.43 All of these suggestions have been examined by later workers.Lockyer and Roberts44 (1874) examined three of these concepts and were very close to an appreciation of the internal standard principle. Hartley described the preparation of matching alloys, similar to samples, to overcome matrix effects.Among the many analyses described is that of a white that had been made during the French revolution in 1798. De G r a r n ~ n t ~ ~ (1902) likewise used standards similar to alloys in question, and named the last lines to disappear on dilution “raies ultimes.” With all the elegant apparatus available and early interest, one would have expected interest and applications in industry, but this was not so, as far as I can deduce from analytical texts of 1900-1 9 15 .47-49 The main problems were due to measurement of amounts of radiation and in variation of intensity with variation in conditions in the source.This latter problem was overcome by Gerlach’s internal standard p r o ~ e d u r e . ~ ~ ~ ~ ~ The equation to evaluate concentrations, however, requires the ratio of line intensities.Owing to the non-linear response of photographic emul- sions, calibration and tedious calculations arise.52 Direct-reading instruments, with photo- multipliers and integration circuits, were subsequently developed and have particular appli- cation in the steel industry. In the period 1880-1928, very little was carried out using flames; despite earlier work, most workers used arc and spark sources.L ~ n d e g a r d h ~ ~ (1928) developed a photographicMay, 1975 ONE HUNDRED YEARS OF ATOMIC SPECTROSCOPY 157 flame system and in 193054 used direct photoelectrical read-out for alkali metals in agriculutral samples. Jansen, Heyes and R i t ~ h e r ~ ~ (1935) developed a monochromatic spectrophotometer system.The first commercial instruments appeared in 1948. The first practical application of atomic absorption appears to be that of the determination of mercury by Hewlett in 1930, referred to in a paper by W o o d ~ o n , ~ ~ using a mercury lamp and phototube; an improved system and cells was reported in lMl.57 A revised format with furnace was described in 1950.58 The idea of using other resonance sources was not put forward until Walsh’s classic paper on atomic-absorption spectroscopy in 1955.59 Current atomic spectroscopic techniques concern emission, absorption and fluorescence.It is salutary to note the state of theory on these subjects prior to the renaissance of atomic spectroscopy in the mid-1950s. All of these topics had been studied in depth by physicists in the early part of this century and detailed in standard texts.60 Equations had been deduced for: (a) the intensity of thermally excited spectral lines; (b) the integral absorption of an atomic line; (c) the maximum absorption of an atomic line; (d) the intensity of fluorescent emission from atoms; and (e) the natural widths of lines and to allow for the effects of various broadening processes.Hollow-cathode lamps, which are an essential part of a modern atomic-absorption instru- ment, were first described by Paschen in 191661 and have since been used extensively by physi- cists. W a l ~ h ~ ~ solved the problem of the need to scan relatively sharp spectral absorption lines in order to measure their integral absorption or their maximum absorption. The width of atomic lines is about 0.002 nm at 2000-3000 K, and therefore high resolution and high costs would arise in the scanning mode.The sharp line of a hollow-cathode lamp is normally less than the half-width of the atomic line arising in the flame or other atomiser and hence maximum absorption is readily measured. The first carbon rod atomiser was that of Gatterer,62 and such systems have since been the subject of intensive study at Imperial College and elsewhere, and have been reviewed recently.63 Atomic fluorescence was described as early as 1905 and suggested for analytical purposes by Alkemade in 1962.64 Results with test elements and the general potentialities were discussed in detail by Winefordner and Vickers in 1964.65 Independently, work was in progress a t Imperial College.66 Atomic fluorescence has multi-element capability but this has not been as easy as was first thought to produce viable commercial equipment.Possibly the best multi-element procedure is to use emission, and an inductively coupled plasma, which has many of the advantages of a flame and few, if any, of its disadvantages.The plasma tail flame is sufficiently hot to ensure complete dissociation and virtual elimination of matrix effects, which is not so for thermal flames. This technique was first reported in 1964. Developments in the last 11 years and its routine application in trace and high percentage ranges with a very wide range of sample types have recently been ~ummarised.~~ Sample volumes may be as low as 1 ~ 1 .~ ~ Other developments in atomic and molecular spectroscopy are also currently being studied by Analytical Division members in the Midlands Region. In molecular emission cavity analysis (MECA), a sample is introduced into a cavity, which is placed in a cool hydrogen flame. The system is simple and has great potential.69 Halide emission such as CuC1,’O arsenic and antimony as h y d r i d e ~ , ~ ~ metal chelates, etc., have been utilised.Another emission phenomenon is that of candoluminescence, where a matrix of calcium hydroxide in calcium sulphate plus small amounts of various salts such as bismuth, manganese and antimony lanthanides give colours in cool flames; from their intensity, quantitation is p~ssible.‘~ A t the end of the period of review, one notes again that there is a great deal of interest in atomic spectroscopy.Annual reviews of the subject are published by the Chemical Society and two Theophilus Redwood lectures, by Alkemade73 and by West,66 were devoted to this subject . References 1. Newton, I., “Opticks,” 1675; Reprinted, Dover, New York, 1952. 2. Marggraf, A. S., Opuscules Chimiques, 1762, 2, 338 and 374.158 3.4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 36. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. ONE HUNDRED YEARS OF ATOMIC SPECTROSCOPY Proc. Analyt. Div. Chem. SOC. Wollaston, W. H., Phil. Trans.R . Soc., 1802, 92, 365. Fraunhofer, J., Annln Phys., 1817, 56, 264. Herschel, J . F. W., Trans. R . Soc. Edinb., 1823, 9, 445. Talbot, W. H. F., Brewster’s J . Sci., 1826, 5, 77. Brewster, D., Rep. 2nd Meet. Br. Ass., 1832, 320. Q. Rev., 1814, 11, 42. Herschel, J . F. W., Phil. Trans. R . SOG., 1840, 130, 1. Alter, D., Am. J . Sci., 1854, 18, 55. Watts, W. M., “Index of Spectra,” H.Gillman, London, 1872. Bunsen, R., Annln Phys., 1857, 100, 43. Wheatstone, C., Phil. Mag., 1835, 7, 299. Bunsen, R., and Kirchoff, G., Annln Phys., 1860, 110, 160. Bunsen, R., and Kirchoff, G., Annln Phys., 1861, 113, 337. Champion, P., Pellet, H., and Grenier, M., C . R. Hebd. Se‘anc. Acad. Sci., Paris, 1873, 76, 707. U . S. Pat. 3,586,446, 1971. Babbage, C., Q. Rev., 1830, 43, 305.“Arcana of Science and Art,” John Limbird, London, 1838. “Intellectual Observer,” Groombridge and Sons, London, 1863. Lawson, H., Editor, “Popular Science Review,” Volume VII, R. Hardwicke, London, 1889. Griffin, W. N., “A Treatise on Optics,” Cambridge University Press, Cambridge, 1842. Rittenhouse, D., Trans. Am. Phil. Soc., 1786, 2, 201. Young, T., Phil. Trans. R.Soc., 1802, 92, 12. Draper, J. W., Phil. Mag., 1845, 26, 465. Rowlands, H. A., Am. J . Sci., 1883, 26, 87. Mitchell, J ., “Manual of Practical Assaying,” H. Balliere, London, 1846. Mitchell, J ., “Manual of Agricultural Analysis,” Simpkin Marshall and Co., London, 1845. Noad, H. M., “Chemical Manipulation and Analysis,” R. Baldwin, London, 1852. Normandy, A., “The Dictionaries to the Chemical Atlas,” G.Knight, London, 1857. Cookesley, T,. H., Editor, “Plattners Manual of Qualitative and Quantitative Analysis with the Brush, G. J . , “Manual of Determinative Mineralogy and Introduction to Blowpipe Analysis,” Sixteenth Read, H. H., “Rutleys Elements of Mineralogy,” Twenty-third Edition, T. Murphy, London, 1942. Browning, J., “How to Work with the Spectroscope,” J.Browning, London, 1878. Mitscherlich, A.. Annln Phys. Chem., 1862, 116, 499. Young, C. L., Annls China. Phys., 1879, 18, 5 . Schellen, H., “Spectrum Analysis.” Longmans Green and Co., London, 1885. Roscoe, H. E., “Spectrum Analysis,” Macmillan and Co., London, 1885. Lommel, E., “The Nature of Light with a General Account of Physical Optics,” Kegan Paul, French McGucken, W., “Nineteenth Century Spectroscopy,” Johns Hopkins Press, Baltimore, 1969.Grove, E. L., Editor, “Analytical Emission Spectroscopy,” Part I, Marcel Dekker, New York, 1971. Szabadvary, F., “History of Analytical Chemistry,” Pergamon Press, Oxford, 1966. Lockyer, J . N., Phil. Trans. R . SOG., 1873, 163, 253 and 639. Lockyer, J. N., and Roberts, W. C., Phil. Trans. R. Soc., 1874, 164, 497.Hartley, W. N., J . Chem. Soc., 1896, 69, 842. De Gramont, A., C. R. Hebd. Se’anc. Acad. Sci.: Paris, 1902, 134, 1048 and 1205. Brearley, H., and Ibbotson, F., “The Analysis of Steelworks Materials,” Longmans Green and Co., Blyth, A. W., and Blyth, M. W., “Foods: Their Composition and Analysis,” C. Griffin and Co., Gooch, F. A., “Methods in Chemical Analysis,” John Wiley and Sons, New Yorlr, 1912.Gerlach, W., 2. Anorg. Chem., 1925, 142, 383. Gerlach, W., and Schweitzer, E., “Foundations and Methods of Chemical Analysis by the Emission Spectrum,” Adam Hilger, London, 1930. Lewis, J., “Spectroscopy in Science and Industry,” Blackie and Son, London, 1933. Lundegardh, H., Ark. Kemi Miner. Geol., 1928, 10, 1. Lundegardh, H., 2. Phys., 1930, 66, 109. Jansen, W.H., Heyes. J.. and Ritcher, C . , 2. Phys. Chem., 1934, A174, 268. Woodson, T. T., Rev. Scient. Instrum. 1939, 10, 308. Ballard, A. E., and Thornton, C. D. W., Ind. Engng Chem. Analyt. Edn, 1941, 13, 893. Zaehlke, C. W., and Ballard, A. E.. Analyt. Chem., 1950, 22, 953. Walsh, A., Spectrochim. Acta, 1955, 7, 108. Mitchell, A. C. G., and Zemansky, M. W., “Resonance Radiation and Excited Atoms,” Cambridge University Press, Cambridge, 1934.Paschen, F., Annln Phys., 1916, 50, 901. Gatterer, A., Spectrochim. Acta, 1942, 2, 252. Kirkbright, G. F., Analyst, 1971, 96, 609. Alkeinade, C. Th. J., “Proceedings of the Xth Coloquium Spectroscopicum Internationale, Maryland, Winefordner, 1. D.. and Vickers. T. 1.. Analvt. &hem.. 1964. 34. 161. Blowpipe, Edition, John Wiley and Sons, New York, 1898. Chatto and Windus, London, 1875. and Co., London, 1888. London, 1902. London, 1909. 1962,” Spartan Books, Washington, D. C., 1963, p. 143. I - I ~ - - 66. West, T. S., Pioc. S O ~ . Analyt. Chew:, .1974, 11, 198. ’May, 1975 SILVER MEDAL 159 67. Greenfield, S., Jones, I. Ll., McGeachin, H. McD., and Smith, P. B., Analytica Chim. Acta, 1975, 74, 68. Greenfield, S., and Smith, P. B., Analytica Chim. Acta, 1972, 59, 341. 69. Belcher, R., Bogdanski, S. L., Ghonaim, S. A., and Townshend, A., Analyt. Lett., 1974, 7 , 133. 70. Belcher, R., Bogdanski, S. L., Ghonaim, S. A., and Townshend, A., Nature, Lond., 1974, 248, 326. 71. Belcher, R., Bogdanski, S. L., Ghonaim, S. A., and Townshend, A., Analyticn Chim. Acta, 1974, 72, 72. Belcher, R., Bogdanski, S. L., and Townshend, A., Talanta, 1972, 19, 1049. 73. Alkemade, C. Th. J., Proc. Soc. Analyt. Chem., 1973, 10, 130. 225. 182.

ISSN:0306-1396    

DOI:10.1039/AD9751200155

出版商:RSC    

年代:1975

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May, 1975 SILVER MEDAL 159 Obituary Alexander Eltringham Heron On March 3rd, 1975, Alex Heron had a heart attack a t home and died soon afterwards. He was born in 1904, educated on Tyneside and his first employment was in Gateshead with the United Alkali Company Limited ; this later became part of ICI. He moved to the ICI Works at Billingham in 1930 and when he retired in 1966 he was Section Manager in the Analytical Group.He was concerned with all aspects of sampling and analysis and was involved in the establishment of IS0 methods for such basic chemicals as nitric and sulphuric acids. He was particularly interested in micro- analysis and gas analysis, on which he published several papers, and he carried out some early work on air pollution. Particular mention should be made of the exacting microanalysis of mineral specimens that he carried out for Professor Holmes of Durham University.160 CONFERENCES AND MEETINGS Proc.AnaZyt. Div. Chem. SOC. He took a keen interest in the Society for Analytical Chemistry and after his retirement he helped to organise the 1971 SAC Conference in Durham. From 1971 to 1973 he served as the Chairman of the North East Region and he was always a staunch supporter of the Society, attending most of the ordinary meetings himself and being accompanied by his wife at many enjoyable social meetings.He also served for many years as auditor of the local RIC/ Chemical Society accounts. His outside interests were wide, but perhaps photography should be specially mentioned ; he won many awards in local and international photographic competitions. To Mrs. Heron and his family we should like to extend our deepest sympathy; he will be greatly missed by all his old friends and former colleagues. A. C. Docherty

ISSN:0306-1396    

DOI:10.1039/AD975120159b

出版商:RSC    

年代:1975

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160 Conferences and Meetings University of Bradford, School of Powder Technology 1975, Bradford The following short courses are to be held at the University of Bradford : Sampling, Particle Size Measurement and Surface Area Measurement . . June 30-July 4 Flow and Storage of Mixing in the Process Industries . . .. . . July 7-11 Application forms can be obtained from the Secretary, Postgraduate School of Powder Technology, University of Bradford, Bradford, Yorkshire, BD7 1DP.Particulate Solids . . July 1-4 McCrone Research Institute Courses 1975, London The McCrone Research Institute is organising a series of courses to be held during 1975. Most of the courses will be of five days’ duration and most will be held a t Bedford College, Regents Park, London. The courses and dates are as follows : Hot-stage Microscopy .. July 7-11 Microscopy in the Pharm- aceutical Laboratory . . July 14-18 X-ray Techniques for Poly- Techniques in Reflected crystalline Materials . . July 21-25 Applied Polarised Light Microscopy .. . . September 8-12 Photomicrography . . September 15-19 Identification of Small Particles . . . . . . September 22-26 Further details can be obtained from the Registrar, McCrone Research Institute, 2 McCrone Mews, Belsize Lane, London, NW3 5BG.CONFERENCES AND MEETINGS Proc. Analyt. Div. Chem. SOC. Polarised Light Microscopy September 1-5 Developments in Electron Microscopy and Analysis September 8-11, 1975, Bristol This meeting, organised by the Electron Microscopy and Analysis Group of the Institute of Physics, will be held at the University of Bristol and has been planned to cover all aspects of electron microscopy except high- voltage microscopy.There will be particular emphasis on the following topics : high-resolution microscopy ; beam-sensitive materials ; boundaries and inter- faces; crystallography ; diffuse scattering ; and quantitative analysis for high elements and thin films.There will also be a special symposium on minerals. Contributions are invited and should be sent, together with an abstract of not more than 200 words, to: Dr. J . W. Steeds, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL. Further information can be obtained from the Meetings Officer, Institute of Physics, 47 Belgrave Square, London, SWlX 8QX.The closing date for registration will be in late July. International Symposium on Liquid Scintil- lation Counting September 16-19, 1975, Bath Delegates wishing to attend the above Sympo- sium are reminded that in order to register a t the reduced fee of f125 their fees must reach the Secretary of the Analytical Division of the Chemical Society by June 3Oth, 1975. Any registrations after this date will be charged at the full rate of f130.Registration entitles delegates to attend the civic reception at the Pump Room, Bath, including a tour of the Roman Baths, and also to attend the Symposium Dinner at the Mendip Hotel. Delegates booking accommodation at the University will be provided with transport to and from the Assembly Rooms. Accommodation is resticted to a total of 300 delegates and therefore early booking is advised.May, 1975 PUBLICATIONS RECEIVED Assay of Drugs and Other Trace Sub- stances in Biological Fluids September 22-24, 1975, Guildford A techniques forum on the above topic will be held at the University of Surrey in Guildford from September 22nd to 24th, 1975.The emphasis wiil be on drugs and drug metabolites of known identity in blood and urine, and the programme will include : Advances in Quantitation Techniques ; Handling the Sample ; Analytical Case Histories ; and Panel Discussions on Choice of Method. Further details and application forms can be obtained from Dr.E. Reid, Wolfson Bioanaly- tical Centre, University of Surrey, Guildford, Surrey, GU2 SXH. Sixth Conference on Molecular Spectro- scopy March SO-April 2, 1976, Durham This Conference, organised by The Hydro- carbon Research Group of the Institute of Petroleum, will be held at the University of Durham.Latest developments in nuclear magnetic resonance spectroscopy, electron spectroscopy, vibrational spectroscopy, applied spectroscopic techniques and the use of tunable lasers in spectroscopic studies will be reviewed.A limited number of contributed papers will be accepted on the application of nuclear magnetic resonance spectroscopy to biological problems and to hydrocarbon type analysis of heavy petroleum fractions, and on the appli- cation of electron spectroscopy to industrial analytical problems. Offers of papers on these subjects should be sent to A. R. West, BP Research Centre, Chertsey Road, Sunbury-on- Thames, Middlesex, TW 16 7LN. An exhibition of spectroscopic instrumenta- tion and accessories will be held concurrently with the conference. Those wishing to have their names put on the mailing list for further details should contact: C. H. Maynard, Institute of Petroleum, 61 New Cavendish Street, London, W1M 8AR. 161

ISSN:0306-1396    

DOI:10.1039/AD9751200160

出版商:RSC    

年代:1975

数据来源: RSC

摘要:

May, 1975 PUBLICATIONS RECEIVED 161 Atomic Absorption and Fluorescence Spectroscopy. G. F. Kirkbright and M. Sargent. Pp. x + 798. London, New York and San Francisco: Academic Press. 1974. Price A17. Publications Received Determination of Gaseous Elements in Metals. Edited by Laben M. Melnick, Lynn L. Lewis and Ben D. Holt. Chemical Analysis Series, Volume 40. Pp. viii + 744. New York, London, Sydney and Toronto: John Wiley & Sons.Price L19.25. Zerovalent Compounds of Metals. L. Malatesta and S. Cenini. Organometallic Chemistry: A Series of Monographs. Pp. viii + 241. London, New York and San Francisco: Academic Press. 1974. Price k7.50; $19-75. Chromatographic Methods. Third Edition. R. Stock and C. B. F. Rice. Science Paperbacks No. 39. Pp. viii + 383. London: Chapman and Hall and Science Paperbacks.1974. Price i 5 - 2 5 (hardback) ; L2.90 (paperback). Isolation and Identification of Drugs in Pharmaceuticals, Body fluids, and Post- mortem material. Edited by E. G. C. Clarke, assisted by Mildred Lang and K. G. Marriott. Volume 2. Pp. xiv + 1258. London: The Pharmaceutical Press. 1975. Price Q3.50. Alcohol in the Blood of New Zealand Drivers.Edited by Q. W. Ruscoe. Information Series No. 101. I p . 80. Wellington: New Zealand Department of Scientific and Industrial Research 1974. Price N.Z.$3. Methodicum Chimicum. Volume 1. Ana- lytical Methods. Part A. Purification, Wet Processes, Deter - mination of Structure. Part B. Micromethods, Biological Methods, Quality Control, Automatization. Pp. x + Edited by Friedhelm Korte.New York, San Francisco and London : Academic Press. 1974. Price i47.05; $98. Pp. x + 1-628. 629-1 2 18. Investigation of Rates and Mechanisms of Reactions. Third Edition. Part I. General Considerations and Reactions at Convent - ional Rates. Edited by E. S . Lewis. Techniques of Chemis- try, Volume V I . Pp. xiv + 838. New York, London, Sydney and Toronto: John Wiley & Sons. 1974. Price k21. Organic Electronic Spectral Data. Vol- ume X. 1968. Edited by John P. Phillips, Henry Feuer and B. S. Thyagarajan. Pp. xvi + 1034. New York, London, Sydney and Toronto : John Wiley & Sons. 1974. Price Ll8.

ISSN:0306-1396    

DOI:10.1039/AD9751200161

出版商:RSC    

年代:1975

数据来源: RSC