摘要:

of the Society for Analytical Chemistry CONTENTS Joint Symposium . . .. 173 Reports of Meetings . . .. 175 Distributions” * . .. I77 on Inorganic Aspects” . . 177 Papers Accepted for The Analyst I82 Publications Received .. .. 183 Forthcoming Meetings Bock Cover “ Presentation of Particle-size “Trace Analysis with Emphasis Proc. SOC. Analyt. Chem. VoI. 7 No. 10 Pages 173-184 October 1970 Vol. 7 No. 10 October 1970 PROCEEDINGS THE SOCIETY FOR ANALYTICAL CHEMISTRY OF President of the Society T. S. West Hon. Secretary of the Society W. H. C. Shaw Hon. Treasurer of the Society G. W. C. Milner Hon. Assistant Secretary of the Society D. 1. Coomber Secretary Miss P. E. Hutchinson 9/10 SAVILE ROW LONDON WIX IAF Telephone 01-734 6205 Editor J. B. Attrill Assistant Editor Miss C. M. Richards Telephone 01-734 3419 Proceedings is published by The Society for Analytical Chemistry and distributed to all members of the Society and t o subscribers with Tbe Analyst; subscriptions cannot be accepted for Proceedings alone.Single copies may be obtained direct from the Society’s Distribution Agents The Chemical Society Publications Sales Office Blackhorse Road Letchworth Herts. (NOT through Trade Agents) price 0 The Society for Analytical Chemistry 5s post free. Remittances MUST accompany orders. REPORTS OF THE ANALYTICAL METHODS COMMITTEE Reprinted from The Analyst Additives in Animal Feeding Stuffs The following thirteen Reports dealing with Additives in Animal Feeding Stuffs may be obtained direct from The Society for Analytical Chemistry Book Department 9/10 Savile Row London WIX IAF (not through Trade Agents) price Is.6d. each t o members of the Society and 2s. 6d. each t o non-members. The Determination of Penicillin Chlortetracycline and Oxytetracyline in Diet Supplements and Compound Feeding Stuffs. The Determination of Stilboestrol and Hexoestrol in Compound Feeding Stuffs. The Determination of Nitrofurazone in Compound Feeding Stuffs. The Determination of Water-soluble Vitamins in Compound Feeding Stuffs. The Determination of Fat-soluble Vitamins in Diet Supplements and Com- The Determination of Amprolium in Animal Feeding Stuffs. The Determination of Sulphaquinoxaline. The Determination of Acinitrazole. The Determination of Ethopabate in Feeds. The Determination of Furazolidone in Feeds. The Determination of Dimetridazole in Animal Feeds. The Determination of Dinitolmide (Zoalene) in Animal Feeds. The Determination of Amprolium Sulphaquinoxaline and Ethopabate when pound Feeding Stuffs. Present together in Animal Feeds (Gratis).

ISSN:0037-9697    

DOI:10.1039/SA97007FX035

出版商:RSC    

年代:1970

数据来源: RSC

摘要:

184 REPRINTS OF REVIEW PAPERS [Proc. SOC. Analyt. Chew. Forthcoming Meetings-continued Wednesday 25th CHROMATOGRAPHY AND ELECTROPHORESIS GROUP Annual General Meeting “Chromatographic Methods Within the Context of Forensic Medicine,” by “The Determination of Physostigmine by Thin-layer Chromatography and “Inter-subject Variation in the Urinary Excretion of Narcotic Analgesics ” by Chelsea College of Science and Technology University of London Manresa SCOTTISH SECTION jointly with the Andersonian Chemical Society. “Modern Trends in Pollution Control,” by G. V. R. Mattock. University of Strathclyde Glasgow; 4 p.m. LONDON followed by a meeting on “Chromatography and Toxicology.’’ Ann E. Robinson. Reflectance Spectrophotornetry,” by G. Smith. D. P. Vaughan. Road London S.W.3; 2.30 p.m. Thursday 26th GLASGOW THE SOCIETY FOR ANALYTICAL CHEMISTRY Forthcoming Meetings-corztinzced Wednesday 1 1 th LONDON Wednesday 1 l t h SUNDERLAND Thursday 12th LONDON Thursday 12th ALCONBURY Friday 13th CHEPSTOW Tuesday 17th MORDEN Wednesday 18th CARLETT PARK Thursday 19th LONDON Thursday 19th BIRMINGHAM Monday 23rd LONDON Tuesday 24th LONDON THERMAL ANALYSIS GROUP Discussion Meeting on “Applications of Thermal “Applications of Thermal Analysis to Some Industrial Problems,” by M.“Applications of D.T.A. to Solid-state Transformations,” by F. P. Glasser. ‘*Further Application of Thermal Analysis to Some Industrial Problems,” by Leicester Lounge 44 Glasshouse Street London W.l; 7.30 p.m. NORTH EAST SECTION. “The Biological Assays of the British Pharmacopoeia ” by Ti. J . Birkinshaw.School of Pharmacy Sunderland Polytechnic Chester Road Sunderland ; THERMAL ANALYSIS GROUP Annual General Meeting followed by a meeting on “The Determination of Quartz in Clay Minerals,” by W. B. Jepson. “D.T.A. of High Alumina and Super-sulphated Set Cement,” by H. G. Midgley. “Thermal Analysis of Portland Cements,” by J . A. Forrester. “Thermal Dissociation of Some Carbonate Minerals,” by R. C. Mackenzie and Wellcome Building Euston Road London N.W.1; 3 p.m. EAST ANGLIA SECTION Annual General Meeting. “On the Purity of Pharmaceutical Products,” by C. A. Johnson. WESTERN SECTION. Discussion on “Water in Industry.” The George Hotel Chepstow; 6.30 p.m. SPECIAL TEcHNIQuEs GROUP Annual General Meeting followed by a meeting Speakers to include C. Narain and J. H. Glover. British Oxygen Company Works Morden.NORTH OF ENGLAND SECTION jointly with the Carlett Park Chemical and “Chemical Magnification-Induction Amplification and Catalysis in Analysis ” West Cheshire Central College of Further Education Carlett Park Wirral AUTOMATIC METHODS GROUP Annual General Meeting. Discussion on “Automatic Methods and Assessment of Environmental Pollu- Wellcome Building Euston Road London N.W.l; 3 p.m. MIDLANDS SECTION Annual General Meeting. “Analytical Applications of Lasers,” by P. J. Hendra. Haworth Lecture Theatre Chemistry Department The University Edgbaston (Please note The date of this meeting has been changed from that previously RADIOCHEMICAL METHODS GROUP Annual General Meeting followed by the Borough Polytechnic Borough Road London S.E.l; 6.30 p.m. PARTICLE SIZE ANALYSIS GROUP Annual General Meeting followed by a Speakers Professor H.Heywood J . E. C. Harris and H. J. Scullion. Physics Lecture Theatre Imperial College London S.W. 7 ; 6.30 p .m. Analysis. ” Landau. A. A. Hodgson. 6.30 p.m. “Thermal Analysis in Mineralogy.” S. St. J. Warne. Huntingdon Research Centre Alconbury; 3 p.m. on “Discharge Methods in Gas Analysis.” Physical Society. by A. Townshend. Cheshire; 6.30 p.m. tion,” to be introduced by D. Moore and H. A. C. Montgomery. Birmingham 15; 6 p.m. advertised). Address of the Retiring Chairman H. J . M. Bowen. meeting on “Particle-size Analysis of Unusual Materials.’‘ [continued on page 184 THE SOCIETY FOR ANALYTICAL CHEMISTRY Forthcoming Meetings October Wednesday 2 1st MANCHESTER Thursday 22nd and Friday 23rd SALISBURY Wednesday 28th LONDON Thursday 29th LONDON November Wednesday 4th LONDON Friday 6th GLASGOW Tuesday 10th LONDON Tuesday 10th LEEDS NORTH OF ENGLAND SECTION.“Changes in Pharmaceutical Analysis,” by E. F. Hersant. University of Manchester Institute of Science and Technology Manchester ; MICROCHEMICAL METHODS GROUP on “Organic Microchemistry and its “Some Aspects of Forensic Analysis,” by Professor C. L. Wilson. “An Investigation of the Rapid Determination of Oxygen in Organic Com- pounds by the Carbon Reduction Method,” by G. Ingrarn. “The Micro Determination of Fluorine,” by Alison M. G Macdonald. “Elemental Analysis ueYsus Physical Pl/lethods,” by J . C. Roberts. “Combustion Methods in Organic Microanalysis,” by Professor R. Belcher. Discussion on “Organic Microchemical Workshop,” to be introduced by S.Bance I. G. Blackwell R. \V. Fennell P. R. W. Baker B. T. Saunderson I;. H. Oliver C. B. Denis and A. C. Thomas. “Minor Constituent Determinations in the Assessment of Pharmaceutical Products,” by C. A. Johnson. “Applications of Organic Microchemical Techniques in the Heavy Chemicals Industry ” by P. Rdarns. “The Determination of Nitrogen and Ammonia in Tobacco,” by Cora W. Ayers. “Microchemical Analysis in Clinical Biochemistry,” by J . A. Durant. Brooks Lecture Theatre Salisbury and South Wiltshire College of Further ATOMIC SPECTROSCOPY GROUP Discussion Meeting. “Light Sources Electrodeless Discharge Tubes ‘ueysus Hollow Cathode Lamps ” to be introduced by J. Richardson and R. M. Dagnall. Leicester Lounge Glasshouse Street London W. 1 ; 7 p.m. BIOLOGICAL METHODS GROUP on “Biological Aspects of Pollution.” Wellcome Building Euston Road London N.W.1; 3 p.m.6.30 p.m. Applications. ” Education Salisbury. SOCIETY Meeting on “Analytical Aspects of Environmental Pollution.” “Organochlorine Compounds in Man and his Environment ” by J . Robinson. “Problems in the Determination of Sitrilotriacetate in Effluent Liquors ” by “Analytical Aspects of Oil Pollution,” by P. G. Jeffery and G. R. E. C. Gregory. “Some Analytical Aspects of Radioactive Effluent Disposal,” by J. TIT. R. Dutton. “A Comprehensive Sampling System for Studying the Relation Between Visibility Other Meteorological Parameters and Atmospheric Pollution,” by A. E. J . Eggleton. G. I;. Longman. The T;liellcorne Building Euston Road London N.W.1; 3 p.m. SCOTTISH SECTION Annual General Meeting. “Tricks of the Trade,” by R. A. Chalmers. Room C129 Thomas Graham Building University of Strathclyde Cathedral Street Glasgow C.1; 5 p.m. MICROCHEMICAL METHODS and EDUCATION AND TRAINIKGROUPS. Discussion on “Training of Microanalysts for Industrial Laboratories.” Imperial College South Kensington London S.TV.7; 6.30 p.m. XORTH OF ENGLAND SECTION jointly with the Leeds University Union Chemical “Anthraquinones as Analytical Reagents ” by M. -4. Leonard. The TJniversity [continued inside back cover Society. Leeds; 5.15 p.m. Printed by W Heffet & Sons Ltd Cambridge England

ISSN:0037-9697    

DOI:10.1039/SA97007BX037

出版商:RSC    

年代:1970

数据来源: RSC

摘要:

October I970 Vol. 7 No. 10 PROCEEDINGS OF THE SOCIETY FOR ANALYTICAL CHEMISTRY Joint Symposium THE Second Joint Symposium to be held by the Society with the Analytical Section of the Royal Dutch Chemical Society took place at Imperial College London on Friday and Saturday April 3rd and 4th 1970. The subject was “Accurate Methods of Analysis for Major Constituents.” There were four plenary lectures two of which were delivered on Friday morning and two on Saturday morning. The afternoons of both days were devoted to the presentation of 27 papers presented in three concurrent sessions. There were 206 delegates from 12 countries and about 15 lady visitors. Professor West President of the Society took the Chair and the proceedings were opened with an address of welcome by Professor Harry Jones Pro-Rector Designate of Imperial College.Professor Jones first made reference to the death a few weeks previously of Lord Jackson who as Pro-Rector was to have opened the Symposium his death was a great loss. He continued with a very brief description of Imperial College an appropriate venue for such a symposium since it was devoted entirely to science and technology. It was one of the largest of its kind with about 4000 students of whom 1400 were post-graduate or research students and it had a long history. It had grown from an association of small colleges and schools about 60 years ago; the first of these schools was the Royal College of Chemistry. From its earliest days the college had had an international outlook; indeed about 40 per cent. of the present research students were from overseas.He was therefore particularly pleased to be welcoming the delegates to an international Symposium. (L-R) Professor Harry Joizes (Pro-Rector Designate) with Dr. A . Dijkstra (President Analytical Section of the Royal Dutch Chemical Society) and Professor T . S. West (President S A C ) The Chair was then taken for the first Plenary Session by Dr. A. Dijkstra President of the Analytical Section of the Royal Dutch Chemical Society the lecturers being Dr. R. F. Rekker who spoke on “The Analysis of Major Constituents in Products of Pharmaceutical Interest,” and Mr. B. Bagshawe on “Metallurgical Analysis with Particular Reference to the Ferrous and Allied Industries.” 173 174 JOINT SYMPOSIUM [Proc. SOC. Analyt. Chem. Professor West took the Chair a t the second Plenary Session on Saturday morning when the lecturers were Dr.R. C. Chirnside on “Major Constituents in Inorganic Systems - A Review of Current Techniques and Requirements,” and Dr. G. J. van Kolmeschate on ‘ ‘S t andardisation Rat ionalisation and International Co-operation in Accurate Analytical Procedures for Major Constituents.” Dr. A . Rekker (Plenary Lecturer) Dr. Dijkstra and Mr. B. Bagshawe (Plenary Lecturer) At the close of the scientific sessions on Saturday Dr. Dijkstra summed up by reminding delegates of the first joint symposium a t Enschede in 1968 a t which the theme had been “Limits of Detection.” Both then and at this Symposium papers had been presented dealing with a wide cross-section of analytical methods. This was a most valuable experience for the individual analyst as it gave him an opportunity to discuss matters of mutual interest with his colleagues.This was especially needed in view of the increasing specialisation now Plenary Lecturers Dr. G. J . van Kolmeschate (L) and Dv. R. C. Chhirnside (R) with one of the overseas delegates Mr. J . Visser prevalent in laboratories either in terms of an industry (e.g. steel analysis and petrochemical products) or in terms of methods (chromatography and spectroscopy). A clear picture of analytical chemistry would not emerge until ways had been found to compare analytical October 1970 REPORTS OF MEETIXGS 175 niethods and to choose rationally from all the methods available to solve the problems put to the analyst. For this besides precision and accuracy interferences and speed it would be wise to evaluate methods in terms of the amount of information they yielded compared with the amount needed.As long as problems remained discussions and symposia would be needed. He ended by expressing all the delegates’ thanks to the organisers of this Symposium to the plenary lecturers and to those who had presented papers for discussion and also to the Symposium’s hosts at Imperial College. SOCIAL PROGRAMME The Social programme began with a Reception on the eve of the Symposium (Thursday evening) which succeeded admirably in its purpose of allowing delegates to become acquainted with one another. The Symposium Dinner was held on Friday evening in the Junior Common Room South Side Halls of Residence. For those delegates who stayed on for the post- Symposium Tour a theatre visit was arranged for the Saturday evening the tour (on Sunday) was via Kunnymede to Windsor where the State Apartments were visited. The highlight of the Ladies’ Programme was on Friday when after a brief visit to Westminster Abbey they were taken on a conducted tour of the House of Commons followed by lunch in the Dining Room overlooking the Terrace at the kind invitation of Sir William Robson Brown M.P. In Sir William’s unavoidable absence the ladies were ably entertained by Mr. Stanley Mchlasters M.P. Some of the overseas visitors went on to Oxford Street to see the shops. On Saturday the ladies went on a tour of the City of London including visits to St. Paul’s Cathedral and the Tower of London.

ISSN:0037-9697    

DOI:10.1039/SA9700700173

出版商:RSC    

年代:1970

数据来源: RSC

摘要:

October 1970 REPORTS OF MEETINGS 175 Reports of Meetings ORDINARY MEETING AN Ordinary Meeting of the Society was held at 7 p.m. on Wednesday October Tth 1970 at the Scientific Societies Lecture Theatre 23 Savile Row London W.1. The Chair was taken by the President Professor T. S. West. A lecture on “The Development of Flame-spectrophotometric Detectors for Gas Chromato- graphy,” was given by Professor Dr. R. Herrmann. NORTH OF ENGLAND SECTION AND RADIOCHEMICAL METHODS GROUP A JOINT Meeting of the North of England Section and the Radiochemical Methods Groupwas held a t 11 a.m. on Thursday September 17th 1970 at the Regional College of Technology Liverpool. The Chair was taken by the Chairman of the Radiochemical Methods Group Dr. H. J. M. Bowen. The subject of the meeting was “Industrial Uses of Radioisotopes,” and it was introduced by the Chairman of the Radiochemical Methods Group Dr.H. J. M. Bowen. The following papers were presented and discussed “Radioactive Measurements in Exploration for and Production of Oil,” by P. Threadgold; “The Use of Neutron Techniques for the Examination of Moving Sample Streams,” by T. B. Pierce; “The Diagnosis of Faults in Chemical Plant by Using Radioisotopes,” by J. F. Ross; “The Use of Radioisotopes in the Investigation of New Drugs,” by H. E. Dobbs; “Experience Gained in the Use of a Radio Gas Chromatograph Detector,” by B. Scales and J. T. A. Webster. SCOTTISH SECTION AN Ordinary Meeting of the Section was held at 4 p.m. on Nonday October 5th 1970 in the Thomas Graham Building University of Strathclyde Glasgow C.1. The Chair was taken by the Vice-chairman of the Section Dr.J. A. Hunter. A lecture on “The Development of Flame-spectrometric Detectors for Gas Chroma- tography,” was given by Professor Dr. R. Herrmann. 176 REPORTS OF MEETINGS [Proc. SOC. Anal’yt. Chem WESTERN SECTION A JOINT Meeting of the Section with the Bristol and District Section of the Royal Institute of Chemistry was held at 10.30 a.m. on Tuesday September 22nd 1970 in the School of Chemistry The University Bristol. The Chair was taken in the morning by the Chairman of the Bristol and District Section of the Royal Institute of Chemistry Dr. J. MacMillan and in the afternoon by the Chairman of the Western Section Dr. T. G. Morris. The subject of the meeting was “Analysis and Control of Pollution’’ and the following papers were presented and discussed; “River Pollution,” by R.Naylor-Firth ; “Atmospheric Pollution,” by R. J. Stephenson; “Pesticide Analysis,” by G. Nickless; “Radioactive Wastes,” by B. Wheatley. EAST ANGLIA SECTION AND CHROMATOGRAPHY AND ELECTROPHORESIS GROUP A JOINT Meeting of the East Anglia Section and the Chromatography and Electrophoresis Group was held a t 2.30 p.m. on Friday September 25th 1970 at the University of East Anglia Norwich. The Chair was taken by the Chairman of the East Anglia Section Mr. C. E. Wat erhouse. The subject of the meeting was “The Applications of Chromatography in Food and Agriculture” and the following papers were presented and discussed “Acid-catalysed Reactions of Monoterpenes,” by D. A. Baines R. Alan Jones T. C. Webb and I. H. Campion- Smith ; “Some Applications of Thin-layer Chromatography to Pesticide Analysis,” by M.Wakefield T. Taylor and J. S. Leahy; “Analysis of Food Constituents by Gas Chromatography and Associated Techniques,” by T. Galliard and P. A. T. Swoboda. MICROCHEMICAL METHODS GROUP THE seventy-fifth London Discussion Meeting of the Group was held at 6.30 p.m. on Wednesday September 30th 1970 in the Buttery Imperial College Princes Gardens South Side London S.W.7. A discussion on “The Determination of Trace Amounts of Organic Contaminants in Industrial Organic Materials,” was opened by G. E. Penketh. The Chair was taken by the Vice-chairman of the Group Mr. S. Bance. EDUCATION AND TRAINING GROUP THE Inaugural Meeting of the Group was held at 2 p.m. on Thursday September 24th 1970 at the University of Technology Loughborough.Delegates were welcomed to the University by the Pro Vice-chancellor Dr. R. L. Cannell. The meeting was opened by the President Professor T. S. West and the following were confirmed as Officers and Committee Members for the forthcoming year Chairman-Dr. W. J. Williams. Vice-Chairman-Mr. J. K. Foreman. Honorary Secretary-Dr. D. Thorburn Burns Department of Chemistry University of Technology Loughborough Leics. Honorary Treasurer-Dr. J. B. Headridge. ,!!embers of Committee-Mr. J. Rassett Mr. W. M. Lewis Mr. J. I. Phillips Dr. J. hl. Skinner and Mr. C. Whalley. Mr. D. Moore and Dr. A. Townshend were appointed as Honorary Auditors. The business meeting was followed by a two-day meeting on “Analytical Chemistry- Industrial and Academic Training.” The Chair at the first session was taken by the Chairman of the Group Dr.W. J. Williams and the following papers were presented and discussed Plenary lecture “Analytical Chemistry Today,” by D. T. Lewis C.B. ; “Training in Industry,” by P. Bennett. Mr. J. K. Foreman Vice-chairman of the Group took the Chair at the second session a t which the following paper was presented and discussed ‘Training in Degree Courses,” by W. J. Williams. The Chair at the third session was taken by the Honorary Treasurer of the Group Dr. J. B. Headridge and the following papers were presented and discussed “Technical and Diploma Courses,” by T. C. Downie ; “Qualifications for Statutory Require- ments,” by D. C. Garratt; “Future Needs in Education and Training,” by H. 0. Puls. The final session took the form of an Open Discussion at which the Chair was taken by Xlr. A. G. Jones Past President of the Society.

ISSN:0037-9697    

DOI:10.1039/SA9700700175

出版商:RSC    

年代:1970

数据来源: RSC

摘要:

October 19701 PRESENTATION OF PARTICLE-SIZE DISTRIBUTIONS 177 Trace Analysis with Emphasis on Inorganic Aspects The following are summaries of some of the papers presented at a Joint Meeting of the Western Section and the Microchemical Methods Group held on July 2nd and 3rd 1970 and reported in the August issue of Proceedings (p. 140). A summary of the paper entitled “Catalytic Methods of Analysis” by A. Townshend (Chemistry Department The University P.O. Box 363 Birmingham 15) was published in the June 1970 issue of Proceedings (p. 95). The Determination of Trace Amounts of Bismuth and Oxygen in Ferrous Alloys BY J. B. HEADRIDGE E. D. RAWSTHORNE AND J. RICHARDSON (Chemistry Department The University Shefield) PARTS per million by weight of bismuth and oxygen in steels can have adverse effects on the properties of these alloys and the determination of such concentrations is often necessary.A method therefore was described for the atomic-absorption spectrophotometric determination of 2 to 130 pg g-l of bismuth in cast irons and stainless steels. From an aqueous solution of an alloy which was 2 . 3 ~ in hydrochloric acid 0 . 0 9 ~ in ascorbic acid and 0 . 2 ~ in potassium iodide the bismuth was extracted quantitatively into isobutyl methyl ketone in one shaking while the base elements remained in the aqueous phase. After concentration the organic phase was nebulised into an air - acetylene flame of a Unicam SP90 atomic-absorption spectro- photometer. The standard deviations in the errors from the means for various cast irons and stainless steels were 1.2 pg g-l and 1.4 pg g-l respectively.The results of applying the solvent-extraction procedure to twenty-seven other elements of interest to the steelmaker were also reported. A method was also described for the determination of from 4 to 50 pg g-1 of oxygen in steels and nickel base alloys. After vacuum fusion of an alloy sample in a graphite crucible 178 TRACE ANALYSIS WITH EMPHASIS ON INORGANIC ASPECTS [PrOC. SOC. Analyt. Cht?m. the amount of carbon monoxide thus produced which was equivalent to the oxygen content of the alloy was determined by mass spectrometry Results agreed closely with those obtained by using vacuum fusion and transducer pressure measurement but the method with the mass-spectrometric finish was much more sensitive than the transducer method. The results of work on oxygen will probably be published elsewhere.An account of the work on bismuth is shortly to be published in The Analyst. Aspects of Pre-concentration and Separation Techniques BY G. NICKLESS (Department of Chemistry The University Bristol) IN trace analysis the trace elements to be determined exist in a “matrix,” which is comprised of the major constituents of the sample. Usually the concentration of these trace elements is p.p.ni. p.p.b. or lower and their absolute amounts are in the microgram or sub-microgram range. Matrices may be inorganic compounds water aqueous solutions and so on as well as various organic - biological compounds. If the matrix does not interfere in the determination of metals and the concentrations of the trace elements present are sufficiently high for determination no difficulties should arise.But often the matrix interferes in the determination of trace elements because of insuffi- cient sensitivity; the accuracy of determinations is not obtained with the matrix present; or it is often impossible to carry out the determination in the presence of the matrix because of interferences. It is well known that the same concentration of a trace element will give different signal responses in different matrices. The standards used in instrumental methods of determination are generally required to duplicate both the chemical and physical nature of the sample as closely as possible. The preparation of suitable standards is one of the most difficult problems in trace analysis. Good standards are available in some cases especially in metallurgical samples but in geological samples and similar materials problems arise.These difficulties are usually overcome by separation or isolation from the matrix before determination and often simple removal is sufficient. Such a separation is known as a pre- concentration step. In special circumstances separations of trace elements from each other are sometimes required in which the co-existing elements interfere with the determination of the desired trace element. By using separation techniques the unfavourable effects from matrix or co-existing trace elements can be eliminated. Theoretically it should be possible to determine infinitely low concentrations of trace elements if we apply the preliminary separation of the matrix to infinitely large amounts of sample. However two important limitations to this concept are as follows.(i) Loss of trace elements-Trace elements tend to be lost during the separation steps; generally the lower the concentration the greater the danger of losses. (ii) Contamination-Contamination including the same element as that t o be determined may be introduced into the sample from various sources. This is one of the most troublesome problems as some types of contamination are not reproducible and are therefore difficult to determine accurately. Obviously with wet chemical procedures the dangers are especially real in the separation step. As phase transfer is nearly always used in the separation step the two solvent phases present in extremely large excess must be of the highest purity. Thus contamination from reagents and apparatus must be considered.Several important considerations in the selection and evaluation of the separation must be investigated including methods of determination available after the separation ; the number of desired trace elements ; the lower limits of concentrations of trace elements ; recoveries of trace elements; Contamination; separation factors; sample size; the number of samples; COM- plexity of the technique; the time required for separation; and labour and cost. The most commonly used separation methods therefore are volatilisation ; liquid - liquid extraction ; precipitation or filtration ; electro-deposition ; ion exchange ; and chromatography. In some cases the matrix is altered into a more favourable one. The usual “blank-run” is often unsatisfactory. October 19701 TRACE ANALYSIS WITH EMPHASIS ON INORGANIC ASPECTS 179 The volatilisation method is widely applicable as either the matrix or trace elements can be volatilised usually a t elevated temperatures on both liquid and solid samples.A great difference in volatility between the components to be volatilised and those to remain in the residue is essential. Naturally this is important when the matrix is to be volatilised as the desired trace elements tend to be lost also. It is more usual for the trace elements to be volatilised; perfect recovery is very difficult. The method has been applied to R 9 Si S Ge As Se Tc Ru Sn Sb Re 0 s and the halogens; for example boron as methyl borate from methanol silicon as silicon tetrafluoride from uranium and protoactinium ; arsenic as arsine from hydrochloric acid solutions ; and sulphur as hydrogen sulphide from nickel.Liquid - liquid extraction is an important separation method because of its simplicity rapidity and wide applicability. The most widely used method is extraction of various metallic elements from an aqueous solution into an organic solvent usually diethyl ether chloroform or carbon tetrachloride. To do this it is necessary to form an uncharged chemical species; the methods include simple co-ordination chelation and ion-association systems. The r61e played by the solvents them- selves must not be overlooked e g . the formation of etherates. Sometimes by using the laws of mass action and equilibria the extraction can be predicted but usually various chemical interactions such as dissociation and polymerisation take place and the distribution ratio of metal becomes dependent on metal concentration.Thus suitable extraction systems reagent concentrations pH and salting-out agents must be chosen. The precipitation and selective dissolution methods include precipitation of the trace element precipitation of the matrix element and selective dissolution of the desired trace element. The latter naturally leads to electro-deposition methods in particular mercury cathode electrolyses which can be followed by anodic stripping voltammetry or volatilisation of the mercury a t 350°C. Finally ion-exchange and chromatographic techniques can be operated either as selective collection or as separation after collection. There are however many choices when using an ion exchanger two interesting features are (i) the possibility of preparing selective chelating groups on an organic matrix; e.g.Chel-100 (unfortunately however ion exchange has not yet achieved the selectivity first predicted for it) ; or (ii) to use the exchanger as a separator e.g. separation of the rare earths on a cation-exchange resin; and separation of transition elements capable of forming anionic complexes with chlorine bromine iodine thiocyanate and fluorine on anion exchangers. These appear to be becoming increasingly important but technology does not appear to be as advanced as for metal analyses. A technique that may be of use in this field is the use of selective electrodes. However it exploits the separation and specificity of ion exchangers either as a solid matrix (e.g. silver sulphide) or liquid exchangers (Orion pCa electrode).For real advancement in this field extra selectivity will be needed. An area that is under-developed is the determination of traces of anions. Time-biased Periodic Differential Electrolytic Potentiornetry BY E. BISHOP AND T. J. N. WEBBER MR. BISHOP said that in most applications symmetrical sine triangular or square-wave polarisation of indicator electrodes offer only a marginal advantage over the simple direct current differential electrolytic potentiometry (D.E.P.) and the introduction of a d.c. bias into the signal destroys the sharpness of the titration curves and may introduce errors. However a mark-to-space (time) biased signal produces surprising results By using a measuring instrument with a time constant long compared with the repetition frequency of the input signal a d.c.output component can be monitored. This is similar to the classical D.E.P. titration curve but the minute errors of the latter with certain reagents vanish the equilib- ration speed and stability of the potentials are greatly enhanced and the precision and discrimin- ation are improved. These advantages extend to titrations at low concentration and are therefore of assistance in trace determinations. (Chemistry Department The Univevsity Stocker Road Exetev Devon) (Shell Research Sittingbourne Ke.tzt) 180 TRACE ANALYSIS WITH EMPHASIS ON INORGANIC ASPECTS [Proc. SOC. Analyt. Chem. Calcium Ion-sens it ive Electrodes BY G. J. MOODY R. B. OKE AND J. D. R. THOMAS (Department of Chemistry University of Wales Institute of Science & Technology Cardifl Wales) DR.MOODY dealt with comparative performances of the Orion 92-20 calcium electrode and the PVC calcium electrode developed by the authors. Both electrodes are based on the calcium salt of didecylphosphoric acid dissolved in material of high molecular weight e.g. di-octylphenylphosphonate and a detailed account of this work will shortly be published in The Analyst. Dr. Moody also referred to applications of these electrodes namely the determination of calcium in Cardiff tap water and of calcium in human serum. Special mention was made of the use of the known addition method for measuring the total concentration of calcium a simple procedure involving only two measurements. In this the potential El is first taken for the sample solution of volume V and total molar calcium content C ..2.303 RT E = constant + 2 F log xlflC * . where x1 is the fraction of ionic calcium and fl the activity coefficient. A small volume V, of a calcium standard of concentration Cs containing about 100 times more calcium than the expected C value but with V about 0.01 of V, is then added to the sample solution. The new potential E, is 2*303 KT log (X2f,Co + x,f2CL\) . . . . . . * * (2) 2 F E = constant + where CA the change in concentration after the known addition stage is given by The subscript 2 refers to the new values for x and f. Combination of equations (1) and (2) gives An essential principle of the known addition method is that x1 - x2 and f - f, so that equation (4) can be simplified to .. .. . . 2.303 RT AE = Dr. Moody then described the results of some initial work on the known addition method for example the PVC electrode gave 1.008 x 1 0 - 3 ~ to 1.056 x 1 0 - 3 ~ calcium for a solution containing 1 0 - 3 ~ calcium while a mixed calciurn - magnesium solution (5 x 1 0 - 4 ~ with respect to each ion) gave a calcium content of 5.1 x 1 0 - 4 ~ to 5-22 x 1 0 - 4 ~ .The results on human serum were also encouraging with results of 2.4 x 1 0 - 3 ~ to 2.7 x 10-3~f total calcium being obtained against a value of 2.9 x 1 0 - 3 ~ by flame photometry. Principles of Selective Ion-sensitive Membrane Electrodes BY G. J. MOODY R. B. OKE AND J. D. R. THOMAS (Department of Chemistry University of Wales Institute of Science 6 Technology Cardifl Wales) AFTER introducing the meaning and measurement of membrane potential Mr. Thomas outlined the various methods of determining the selectivity of ion-sensitive membrane electrodes.These depend on the fact that an electrode responding primarily to say a cation Mz+ can have its e.m.f. response E interfered with by a species Nnf depending on the value of the selectivity constant KMN E = E" + 2.303 RT Z F Except for the sign the relationship for anions is the same. October 19701 TRACE ANALYSIS WITH EMPHASIS ON INORGANIC ASPECTS 181 With divalent cations the methods used for determining KMN are based on e.m.f. observ- ations in separate (Method I) and in mixed (Method 11) solutions of the primary ion interfering ion N2+ METHOD IA- A separate plot of the electrode's e.m.f. response against log activity (log a) is the primary ion M2+ and the interfering ion N2+ the respective responses being E - E" + 2*303 RT log aM3+ .. . . . . .. 2 F 1 - and log KMN aNZ+ . . . . * . 2.303 RT 2 F E2 = E" + . . M2+ and made for given by * ' (2) * * (3) When a M z + is equal to aNz+ the difference between equations (2) and (3) simplifies to and K, can be readily calculated. METHOD IB- to E when the difference between equations (2) and (3) simplifies to In this case the results of method IA are used under the conditions in which E is equal . . .. * * (5) KMN = aMz+/aNz+ . . .. . . NETHOD IIA- Potentials are measured in solutions containing a fixed activity of interfering ion aNz+ with varying activities of the primary ion M2+ for which the electrode is designed. The selectivity constant KMN is then determined by using equation (5) for the conditions existing at the intercept of the extrapolatedNernstian response line for M2+ with the horizontal line of the total interference due to N2+.Frequently however the activity of M2-t correspond- ing to an e.m.f. response of 9 mV (i.e. 18/z) above the Nernstian response line is taken in preference to that at the actual intercept. METHOD IIB- varied against a constant level of the primary species M2+. This is the reverse of alternative IIA in that the activity of the interfering ion NZ+ is METHOD IIC- In this alternative one of two complicated equations is used one for high values of K, and the other for low values. For the former the e.m.f. response E, is measured in a pure solution of the primary ion say X2+ and known amounts of the interfering ion say X2+ are successively introduced to give a series of potential values E, for the mixed solutions- log aMZc ... . * * (6) log (a'Mz+ + KM a'Nz+) . . . . (7) 2.303 RT 2 F El = E" + 2-303 RT 2 F E = E" + Combination of these equations gives (ex;G) a,%+ - a'Ma+ = K ~ atN2+ . . . . .. * * (8) whereby from a plot of the left-hand side against the interfering ion activity aNz+ K, can be calculated from the linear slope. When KhfN is low the potential cannot be expected to be sensitive to small increases in the activity of interfering ion hence a fairly high level of interfering ion is maintained and 182 PAPERS ACCEPTED FOR PUBLICATION [PYOC. SOC. Aaalyt. CheYlZ. potentials E, are measured after additions of primary ion the appropriate version of equation (1) now being used for E,. The more complicated equation can be used for calculating KMN from the slope of the linear plot of the complete left-hand side against the square bracket function of the right-hand side. Mr. Thomas concluded with a brief survey of the various types of selective ion-sensitive electrodes now available.

ISSN:0037-9697    

DOI:10.1039/SA970070177b

出版商:RSC    

年代:1970

数据来源: RSC

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I82 PAPERS ACCEPTED FOR PUBLICATION [PYOC. SOC. Aaalyt. CheYlZ. Publications Received The publications listed below have been received by the Editor of The A Ycalyst in which journal Book Reviews will continue to appear. ISFRAREUVAPOURSPECTRA. By D. WELTI. Pp. xii+211. London NewYorkand RheinePVestf. 1970. Price INTRODUCTION TO MOLECULAR SPECTROSCOPY. By E. F. H. BRITTAIN W. 0. GEORGE and C. H. J. SOLVENT EXTRACTION OF METALS. Pp. x + Van Nostrand Reinhold Co. Heyden & Son in cooperation with Sadtler Research Labs. Inc. Philadelphia. 170s.; DM77; $21.00. WELLS. Pp. xii + 387. London and New York Academic Press. 1970. Price 120s. 259. 1970. Price 120s. By A. K. DE S. M. KHOPKAR and R. A. CHALMERS. New York Cincinnati Toronto Melbourne and London : October 19701 REPRINTS OF REVIEW PAPERS 183 TOPICS IN ORGANIC MASS SPECTROMETRY.Edited by A. L. BURLINGAME. Pp. xii + 471. New York London Sydney and Toronto Wiley-Interscience a division of John TViley & Sons. 1970. Price L l O 11s. APPLICATIONS IN AGRICULTURE BIOLOGY AND MEDICINE. By GARY D. CHRISTIAN and FREDERICK J . FELDMAN. Pp. x + 490. New York London Sydney and Toronto Wiley-Interscience a division of John Wiley & Sons. 1970. Price 165s. TASCHENBUCH FUR CHEMIKER UND F’HYSIKER. PART 111. EIGENSCHAFTEN VON ATOMEX UND MOLEKELN. Pp. viii + 670. Edited by PROF. DR. KLAUS SCHAFER and DR. CLAUDA SYNOWIETZ. Berlin Heidelberg and New York 1 Springer Verlag. 1970. Price DM48; $13.20. DEVELOPMENTS IN APPLIED SPECTROSCOPY. VOLUME 7B. Edited by E. L. GROVE and A. J. PERKINS. Pp. xii + 291. New York and London Plenum Press.1970. Price $12.50. GUIDE TO FLUORESCENCE LITERATURE. VOLUME 2. By RICHARD A. PASSWATER. Pp. viii + 369. New York Washington and London IFIIPlenum. 1970. Price $22.50. ATOMIC ABSORPTION SPECTROSCOPY. NMR SPECTROSCOPY IN ORGANIC CHEMISTRY. MOSSBAUER EFFECT METHODOLOGY. VOLUME 5. By B. I. IONIN AND B. A. ERSHOV. Pp. x + 382. Proceedings of the Fifth Symposium on Moss- Edited by IRWIN J. GRUVERMAN. ADVANCES IN CHROMATOGRAPHY. VOLUME 9. Edited by J. CALVIN GIDDINGS and ROY -4. I~ELLER. INSTRUMENTAL ANALYSIS MANUAL. MODERN EXPERIMENTS FOR THE LABORATORY. By GEORGE 1970. THE CHEMICAL SOCIETY ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY. VOLUME 66. PROCEEDINGS OF THE I11 ANALYTICAL CHEMICAL CONFERENCE. BUDAPEST AUGUST 24 - 29 1970. Budapest Akedamiai Kiado. MARINE CHEMISTRY.VOLUME 11. THEORY AND APPLICATIOSS. By DEAN F. MARTIN. Pp. xii + CHEMISTRY AND PHYSICS OF CARBON. Pp. xiv + 354. APPLIED SPECTROSCOPY REVIEWS. VOLUME 3. Edited by EDWARD G. BRAME jun. Pp. xii + New York and London Plenum Press. 1970. Price $25.00. bauer Effect Methodology New York City February 2 1969. Pp. viii + 278. New York and London Plenum Press. 1970. Price $19.50. Pp. xiv + 358. New York Marcel Dekker Inc. 1970. Price $18.75; 178s. G. GUILBAULT and LARRY G. HARGIS. Price $7.75. SECTION A. Pp. vi + 469. London The Chemical Society. 1970. Price 150s. VOLUMES I and 11. Pp. (Volume I) 318; Pp. (Volume 11) 459. 1970. Price 180s. 451. New York Marcel Dekker Inc. 1970. Price $9.50; 90s. New York Marcel Dekker Inc. 1070. Price $23.50; flll 4s. 345. New York Marcel Dekker Inc. 1970. Price $17.50; 167s. Pp. xii + 444. New York Marcel Dekker Inc. VOLUME 6. Edited by PHILIP L. WALKER.

ISSN:0037-9697    

DOI:10.1039/SA970070182b

出版商:RSC    

年代:1970

数据来源: RSC

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October 19701 REPRINTS OF REVIEW PAPERS 183 Reprints of Review Papers REPRINTS of the following Review Papers published in The AyLaZyst since January 1962 are available from The Society for Analytical Chemistry Book Department 9/10 Savile Row London WlX 1AF (not through Trade Agents). Orders MUST be accompanied by a remittance for the correct amount made out to “Society for Analytical Chemistry.” “Emission Spectroscopy of Solutions,” by L. G. Young (January 1962). “Analytical Applications of the Mercury Electrode,” by J. A. Page J. A. Maxwell and R. P. “Classification of Methods for Determining Particle Size,” by the Particle Size Analysis “Methods of Separation of Long-chain Unsaturated Fatty Acids,” by A. T. James (August “Beer’s Law and its Use in Analysis,” by G. F. Lothian (September 1963).“A Review of the Methods Available for the Detection and Determination of Small Amounts Price 5s. Graham (April 1962). Price 5s. Sub-committee of the Analytical Methods Committee (March 1963). 1963). Price 5s. Price 5s. Price 5s. of Cyanide,” by L. S. Bark and H. G. Higson (October 1963). Price 5s. 184 REPRINTS OF REVIEW PAPERS [Proc. SOC. Analyt. Chew. “Circular Dichroism,” by R. D. Gillard (November 1963). “Information Retrieval in the Analytical Laboratory,” by D. R. Curry (November 1963). “Thermogravimetric Analysis,” by A. W. Coats and J. P. Redfern (December 1963). Price 5s. ‘‘Some Analytical Problems Involved in Determining the Structure of Proteins and Peptides ” “The Faraday Effect Magnetic Rotatory Dispersion and Magnetic Circular Dichroism ” by “Electrophoresis in Stabilizing Media,” by D.Gross (July 1965). “Recent Developments in the Measurement of Nucleic Acids in Biological Materials,” by “Radioisotope X-ray Spectrometry,’’ by J. R. Rhodes (November 1966). “The Determination of Iron(I1) Oxide in Silicate and Refractory Materials,” by H. N. S. “Activation Analysis,” by R. F. Coleman and T. B. Pierce (January 1967). “Techniques in Gas Chromatography. Choice of Solid Supports,” by J. F. Palframan Price 5s. “Heterocyclic Azo Dyestuffs in Analytical Chemistry,” by R. G. Anderson and G. Nickless “Determination of Residues of Organophosphorus Pesticides in Food,” by D. C. Abbott and “Radioactive Tracer Methods in Inorganic Trace Analysis Recent Advances,” by J. W. “Gamma-activation Analysis,” by C. A. Baker (October 1967). “Precipitation from Homogeneous Solution,” by P.F. S. Cartwright E. J . Newman and D. W. Wilson (November 1967). “Industrial Gas Analysis,” by (the late) H. N. Wilson and G. M. S. Duff (December 1967). Price 7s. 6d. “The Application of Atomic-absorption Spectrophotometry to the Analysis of Iron and Steel,” by P. H. Scholes (April 1968). “Inorganic Ion Exchange in Organic and Aqueous - Organic Solvents,” by G. J . Moody and J. D. R. Thomas (September 1968). “Radiometric Methods for the Determination of Fluorine,” by J. K. Foreman (June 1969). Price 5s. “Techniques in Gas Chromatography. Developments in the van Deemter Rate Theory of Column Performance,” by E. A. Walker and J. F. Palframan (August 1969). Price 5s. “Techniques in Gas Chromatography. Choice of Detectors,’’ by T. A. Gough and E. A. Walker (January 1970). “Laser Raman Spectroscopy,” by P. J . Hendra and C. J . Vear (April 1970). Price 7s. 6d. “Ion-selective Membrane Electrodes,” by Ern0 Pungor and KlAra T6th (July 1970). Price 2s. 6d. Price 2s. 6d. by Derek G. Smyth and D. F. Elliott (February 1964). J. G. Dawber (December 1964). Price 5s. Price 5s. Price 5s. H. N. Munro and A. Fleck (February 1966). Price 5s. Price 5s. Schafer (December 1966). Price 5s. Price 5s. Part I. and E. A. Walker (February 1967). (April 1967). Price 5s. H. Egan (August 1967). McMillan (September 1967). Price 5s. Price 5s. Price 5s. Price 5s. Price 5s. Price 7s. 6d. Part 11. Part 111. Price 5s. Price 7s. 6d.

ISSN:0037-9697    

DOI:10.1039/SA9700700183

出版商:RSC    

年代:1970

数据来源: RSC