摘要:

Proceedings of the Society for Analytical Chemistry CONTENTS Reports of Meetings . . .. 127 Meeting to inaugurate North East Section . . .. .. 127 Papers accepted for The Analyst I 3 I “Special Techniques in Gas “New Aspects of Infrared Analysis” . . .. .. 132 Spectrometry ” .. .. 136 Publications Received . . .. 138 Proc. SOC. Analyt. Chem. VoI. 3 No. 8 Pages 127-138 Notices .. . . Inside Back Cover Forthcoming Meetings . . Back Cover August 1966 Vol. 3 No 8 PROCEEDINGS OF August 1966 THE SOCIETY FOR ANALYTICAL CHEMISTRY President of the Society A. A. Smales O.B.E. Hon. Secretary of the Society S. A. Price Hon. Treasurer of the Society D. T. Lewis C.B. Hon. Assistant Secretaries of the Society B. S. Cooper; D. W. Wilson Secretary Miss P. E. Hutchinson 14 BELGRAVE SQUARE LONDON S.W.1 Telephone BELgravja 3258 Editor J.B. Attrill Proceedings is published by The Society for Analytical Chemistry and distributed t o members and all subscribers t o The Analyst without charge Single copies may be obtained direct from the Secretary The Society for Analytical Chemistry a t the above address (NOT through Trade Agents) price 2s. 6d. post free. Remittances payable t o “Society for Analytical Chemistry” MUST accompany orders REPORTS OF THE ANALYTICAL METHODS COMMITTEE Reprinted from The Analyst Recommended Methods of Assay of Crude Drugs Reprints of six Reports prepared by Panels appointed by the Joint Committee of the Pharmaceutical Society and the Society for Analytical Chemistry on Methods of Assay of Crude Drugs are available direct from the Secretary The Society for Analytical Chemistry 14 Belgrave Square London S.W.1 (not through Trade Agents) price Is.6d. t o members of the Society for Analytical Ch:mistry and 2s. 6d. t o non-members. A remittance made out t o Society for Analytical Chemistry” MUST accompany every order. “The Determination of Rotenone in Rotenone-bearing Plants with Special “Assay of Rauwolfia” (reprinted from The Analyst 1960 85 755-764). “The Colorimetric Determination of Rotenone” (reprinted from The Analysl 1961 86 748-755). “The Determination of the Capsaicin Content of Capsicum and its Preparations” (Second Report of the Panel) (reprinted from The Analyst 1964 89 377-388). This report supersedes the first report of the Panel published in 1959. “The Assay of Pyrethrum” (reprinted from The Analyst 1964 89 “The Chemical Assay of Senna Fruit and Senna Leaf’’ (reprinted from The Reference to Lonchocarpus” (reprinted from The Analyst 1959,84 735-742). 689-706). Analyst 1965 90 582-588).

ISSN:0037-9697    

DOI:10.1039/SA96603FX023

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

NOTICES Notices THE INSTITUTE OF PHYSICS AND THE PHYSICAL SOCIETY ATOMIC-ABSORPTION ANALYSIS AND INSTRUMENTATION DEVELOPMENT THE Spectroscopy Group of the Institute of Physics and the Physical Society and the Atomic Absorption Spectroscopy Group of the Society for Analytical Chemistry are arranging a joint meeting t o be held in London in February 1967. It is intended that the theme of the meeting should be on the fundamental processes of atomic-absorption analysis and recent develop- ments in instrumentation. Off ers of contributions relating to these processes and develop- ments are welcomed and outlines of not more than 300 words (preferably typed on quarto paper or A4 in double line spacing) should be sent to the Meeting Secretary Mr. R. J. W. Powell Hirst Research Centre G.E.C. Ltd.East Lane Wembley Middlesex as soon as possible but not later than October 14th 1966. Residential accommodation is not being arranged. Advance registration for attendance at the meeting will be necessary and further details and application forms will be available in November 1966 from the Meeting Office the Institute of Physics and the Physical Society 47 Belgrave Square London S. W. 1. INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY INFORMATION BULLETIN NUMBER 25 FEBRUARY 1966 A JOINT IUPAC - IUB Commission on biochemical nomenclature when it last met in Paris in 1965 issued Tentative Rules for giving trivial names of miscellaneous compounds of importance in biochemistry; has made recommendations for the nomenclature of quinones with iso- prenoid side-chains and abbreviated designation of amino-acid derivatives and polypeptides ; and made tentative recommendations for abbreviations of terms relating to plastics and elastomers.These are all included in IUPAC information bulletin No. 25 February 1966; the bio- chemical recommendations have been reported in Biochim. Biophys. Acta 1965 107 1-13. Forthcoming Meetings-couztkmued. September Wednesday 21st BIRMINGHAM Wednesday 21st DURHAM Friday 23rd GLASGO w Thursday 29th CHESTER Midlands Section jointly with the Birmingham and Midlands Section of the “Some Aspects of the Polarography of Unsaturated Aliphatic Acids,” by M. L. “Some Aspects of the Analytical Chemistry of Soil Humic Acids and Related “The Determination of Citric Acid,” by A. R. Witty B.Sc. A.R.I.C. Haworth Lecture Theatre Chemistry Department The University Edg- NORTH EAST SECTION.“Some Recent Developments in Absorption Spectrometry Molecular and The University Durham; 6.30 p.m. SCOTTISH SECTION. “The Initiation Development and Testing of Analytical Methods in Industry,” University of Strathclyde Glasgow; 6 p.m. ATOMIC-ABSORPTION SPECTROSCOPY GROUP. “Fluorescence of Metal Atoms in Flames,’’ by D. J . Jenkins. “High Temperature Flames,” by W. Slavin. Thornton Research Centre Chester; 10 a.m. Society of Chemical Industry on “Determination of Organic Acids.’’ Richardson A.C.T. A.R.I.C. and P. E. Luton L.R.I.C. Synthetic Materials,” by J . M. Thompson M.Sc. baston Birmingham 15; 3 p.m. Atomic Fluorescence,” by Professor T. S. West Ph.D. D.Sc. F.R.I.C. by J . Haslam D.Sc. F.R.I.C. THE SOCIETY FOR ANALYTICAL CHEMISTRY Forthcoming Meetings September Friday 2nd ABERDEEN Wednesday 14th ENFIELD Wednesday 14th to Friday 16th LOUGHBOROUGH Friday 16th and Saturday 17th CANTERBURY Tuesday 20th LONDON SCOTTISH SECTION “A Critical Study of Oxine,” by R.A. Chalmers B.Sc. Ph.D. F.R.I.C. and “Semi Micro Gas Chromatographic Method for the Determination of Alkoxy “Decay Chronopotentiometry,” by D. J. Barclay B.Sc. “Gas - Liquid Chromatography in a Pharmaceutical Control Laboratory,” by “Atomic-absorption Techniques in Analysis of Soil and Plant Extracts,” by “Some Preliminary Observations on Molecular-sieve Chromatography ” by Department of Chemistry University of Aberdeen ; 10 a.m. Mohammed Basir M.Sc. Groups,” by A. F. Williams B.Sc. F.R.I.C. J. S. Foster B.Sc. A.R.I.C. R. C. Voss B.Sc. A.R.I.C. D. M. W. Anderson B.Sc.Ph.D. F.R.I.C. THIN-LAYER CHROMATOGRAPHY GROUP on “Applications of Thin-layer Chromatography in the Pharmaceutical Industry.” Enfield College of Technology Queensway Enfield; 2 p.m. SOCIETY. Conference on “Particle Size Analysis.” For details of programme Loughborough College of Technology Loughborough. MICROCHEMICAL AND RADIOCHEMICAL METHODS GROUPS on “Radiochemical Fviday- Inaugural Meeting of the Radiochemical Methods Group ; 9.45 a.m. “ Radiochemical Methods,” by Professor G. R. Martin A.R.C.S. BSc. F.R.I.C. “Micro Determinations by Radioactive Isotope Dilution Analysis,” by T. T. “Trace Element Determination by Radioactivation Analysis,” by D. Gibbons Lecture Theatre Physical Sciences Building University of Kent Canterbury ; Visits to Woodstock Agricultural Research Centre “Shell” Research Ltd.Satuvday- Tour of the University of Kent; 10 a.m. “Liquid Scintillation Counting,” by F. H. Kendall B.Sc. Ph.D. F.R.I.C. “Radiochemical Studies of Pesticide Metabolism in Crops and Soils,” by “Some Uses of Labelled Compounds in Industrial Research,” by J . Whiston Lecture Theatre Physical Sciences Building University of Kent Canterbury; Informal Discussion on “Working Methods in Radiochemical Microanalysis,” see July issue of Pvoceedings p. 122. Methods in Microanalysis.” Gorsuch B.Sc. Ph.D. A.R.I.C. Ph.D. A.R.I.C. 10 a.m. Sittingbourne or to Bowater’s Paper Mill Kemsley; 1.45 p.m. and D. R. Pollard B.Sc. Ph.D. A.R.I.C. A. N. Wright M.A. Ph.D. B.Sc. Ph.D. 2.15 p.m. introduced by D. Lambie B.Sc. F.R.I.C. Eliot College; 7.45 p.m. SPECIAL TECHNIQUES GROUP 21st Anniversary Meeting and Dinner. Dinnev-Members’ Dining Room House of Commons London S.W. 1 ; Coitztimed inside back covey 6.30 p.m. Printed by W Heffer & Sons Ltd Cambridge England

ISSN:0037-9697    

DOI:10.1039/SA96603BX025

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

August 1966 Vol. 3 No. 8 Meeting of the Society THE inaugural meeting of the North East Section which has been formed to cater for analysts in the area north of Northallerton and east of the Pennines took place on Tuesday May 17 1966. The meeting which was held at the Central Laboratories of British Titan Products Company Ltd. Stockton-on-Tees was preceded by a tour of the laboratories. Fifty-two members of the Society including the President three Past Presidents two Vice-presidents the Honorary Secretary and Programme Secretary and fifteen visitors were present. The first Society for Analytical Chemistry Gold Medal was presented by the President Dr. A. A. Smales O.B.E. during the meeting to Herbert Newton Wilson formerly Analytical Group Manager of Imperial Chemical Industries Ltd. (Billingham Division and later Agri- cultural Division). After the presentation Mr. R. C. Chirnside gave a lecture entitled “Analytical Chemistry- A Nonconformist View.” Further details are given on the next pages.

ISSN:0037-9697    

DOI:10.1039/SA966030127b

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

128 PRESIDENTIAL SPEECH [Proc. SOC. Analyt. Chew. Presentation of the Society’s Gold Medal by the President THE PRESIDENT opened the meeting by saying This is a special meeting of the Society for Analytical Chemistry to mark the inauguration of the North East Section and has been arranged by the North East Section Committee. At the last Council the new Section was formally agreed and Mr. Smith your Chairman-Elect was received as the Chairman of the Section and took his place on Council. We wish the new Section all success and we look forward to a flourishing and active programme bringing the opportunity to an ever growing number of analytical chemists to attend meetings and join in discussion in this rapidly expanding branch of science. It is pure coincidence that we are making this presentation to a North Easterner at an inaugural meeting for the North East Section.The Honours Committee was appointed by Council following the decision to make awards of a new Society Medal to outstanding analytical chemists. The Committee consists at the moment of the President the three immediate Past Presidents the Honorary Treasurer and Honorary Secretary-all I may say forthright men of strong conviction. The Committee started its considerations by setting up several criteria to aid it in making its choice of nominee. Some of these criteria not necessarily in order of importance were- He should be British recognised and willing to be recognised as an analytical chemist. The quality of his published work and his particular contribution to analytical chemistry. The positions he has held.His influence on the quality of people trained under him. His work for the Society (this was considered to be of rather lesser importance but might be of use in borderline cases). There were about 25 names on the preliminary list of possible nominees for consideration I am glad to be able to tell you that not only was the Committee unanimous in itsrecom- mendation of H. N. Wilson but that the Council accepted that recommendation unanimously and with acclamation. I know that you are all aware of the scientific contributions made by H. N. Wilson some of them are listed in the announcement of the award in the April issue of l h e Analyst the journal of the Society for Analytical Chemistry. I will not repeat that list-suffice it to say that it is formidable and one that any scientist would be justly proud of even with the advantages of an academic position rather than the industrial posts held by “H.N.” But perhaps not so many of you are as aware of the other sides of “H.N.” Those who had the benefit of working under him know that his standards were high-very high! The young scientifically-inclined grammar-school-boy intake into the I.C.I.Billingham in the 1930’s and subsequently was I believe at any rate so far as the Research Department was concerned fed into the Analytical Section as it was then for “preliminary training.” So there was a certain military even perhaps “square bashing” atmosphere about-perhaps I exag- gerate-Mr. Wilson? However whether the rest of the Research Department ever realised it or not I don’t know but it was the firm conviction among those youngsters that only the best of them remained in the Analytical Section.Certainly it was clear that the quality of training was better there that although strict “H.N.” was fair that he would encourage those who were willing to work for an external degree and that he would provide the variety of training in the many branches of analytical chemistry that I.C.I. Billingham was fortunate to have. So there was undoubtedly a “corps d’elite” spirit in that Analytical Section and a healthy competitive atmosphere between the various units in it; altogether a fine laboratory for an ambitious youngster and one which has set the pattern for many others in this country. And the man mainly responsible? H. N. Wilson. And as they developed those who “survived” began to realise the debt that they owed Not only a scientist in the full sense of that word he was a man of letters of art And he set the exam$le for many young men to To that honour which I know he quietly prides it is my pleasure to add tangible Sir on behalf of the Society for Analytical Chemistry I am delighted to make this My next duty is to make the presentation of the Society’s medal to Mr. H. N. Wilson. this man. and of music. follow. evidence. the first award of the Society’s Medal to you Mr. H. N. Wilson. Indeed a man of cuZture. August 19661 ANALYTICAL CHEMISTRY-A NONCONFORMIST VIEW MY. Wilson (R) Yeceiving the medal .fvom the Pvesident 129

ISSN:0037-9697    

DOI:10.1039/SA9660300128

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

August 19661 ANALYTICAL CHEMISTRY-A NONCONFORMIST VIEW 129 Analytical Chemistry-A Nonconformist View BY R. C. CHIRNSIDE (The Geneva1 Electvic Co. Ltd. Centval Reseavch Labovatovies Hivst Research Centre Wevnbley Middlesex) MR. CHIRNSIDE said that he thought inaugural meetings should be concerned in the main with the future and he was seriously concerned about the future of analytical chemistry. Twenty-one years ago in another inaugural address entitled “Physics and the Analyst,” he had been rash enough to indulge in prophecy. On re-reading this address given on the formation of the Physical Methods Group some of these prophecies would seem to have been near the mark. He had said then that “it was clear that it would no longer be possible for analysis in the widest sense of the word to be anything but a co-operative effort of a number of experts each having some considerable knowledge of the work of the other members of the team.For too long he had been the poor relation of the chemical fraternity.’’ At first sight the status of both analytical chemistry and of the analyst himself would seem to have grown immeasur- ably. Even our academic institutions would seem at last to have seen the light-three Chairs in analytical chemistry and courses being offered in many colleges in analytical (and in advanced ! analytical) chemistry. Nevertheless in his Presidential Address to the Society in 1961 he had confessed to a certain degree of unease and he was still uneasy about the situation. It was pertinent to examine the present academic outlook both here and in the United States of America.With the developments in the teaching of modern inorganic chemistry there had been a revolt against the practical courses of the past. He had some sympathy with this attitude which had been summed up by Professor Nyholm as follows “The distinctly separate objectives of qualitative analysis as a vehicle for the transport of simple ideas of chemistry on the one hand and as a utilitarian advanced analytical course in identification on the other have become hopelessly mixed up at the expense of the students’ interest in inorganic chemistry.’’ The status of the analyst might grow again-and there was room for growth. 130 ANALYTICAL CHEMISTRY-A NONCONFORMIST VIEW [Proc. Soc. AnaZyt. Chem. But he wondered if in their new approach our academics had not leap-frogged analytical chemistry jumping off at the qualitative analysis of a mixture of six radicals and landing on some modern physical methods of measurement and in the process jumping over the hard core of analytical knowledge and skills on which industry depended.It was difficult to avoid the implication that all classical analytical chemistry was believed to be time-consuming that all of it was messy and that many of the results were suspect. It would be unfortunate if the idea got about that it could all be replaced here and now by the installation of a series of automatic analytical “juke-boxes.” Nor was the problem confined to Britain. He suggested that his audience might profitably read the discussions in the February and March issues of Analytical Chemistry discussions stimulated in part by the recent publication of the Westheimer report.In this report six newly designated areas of chemistry had been proposed in place of the conventional division into inorganic organic and physical chemistry. In his view if analytical chemistry was remembered at all it must surely lie in the area designated as “structure physical properties and characterisation.” Historically the analytical laboratory was established as a first and laudable effort to bring science into industry. It was believed that a measure of control would result from the information provided and on this basis the analyst was still providing indigestible masses of figures some of them in his judgment quite useless and many of them too late to be of any but post-mortem value. He knew and fully understood the legitimate uses and need for those aspects of analysis more properly called “assaying” or even “testing,” but today there was too little regard for the fact that analytical figures had little or no intrinsic value unless they could be put to good use.The analyst had too often become absorbed in the mechanics of his task and had given too little thought to and made too little insistence on his ability to help in the delineation of problems to which analysis was expected to provide an answer. Analytical chemistry in its golden period had enjoyed the status of a research activity. When the emphasis had shifted to the commercial control of materials by analysis or test; to fix a price; to meet a specification; when the objectives seemed no longer to be so unam- biguously scientific; then the status of analytical chemistry and the status of the analyst began to fall.It could not be re-established by the asking nor yet by the adoption of modern techniques of separation or of instrumental methods of measurement. There had to be a change in analytical thinking a new philosophy if they were to avoid a situation in which they would merely produce in much larger quantity and in a much shorter time the out-of-date kind of information they used to obtain by more tedious methods. They had to realise that today they were often concerned to use materials-which were after all chemicals however non-ideal-for more sophisticated purposes and if scientific understanding and control were to be achieved the techniques of examination and characterisation assumed a new importance.Not only were there new methods and techniques for obtaining analytical information but there were many new and important kinds of information to be obtained. Often this new information offered greater possibilities of translation into a useful and satisfying statement of the properties of a material system. While the analyst must therefore accept his service function it would be justified and recognised only if it was seen to make its major contribution to an activity outside itself. He must not therefore continue to accept or allow others to impose on him a static or a permanent conception of what constituted analytical information. To do so would be to run the risk either of overlooking vital information about materials or of leaving such measure- ments as were required to be made in isolation by those less than expert in the analytical discipline.There were already many scientific workers both chemists and physicists engaged in the application of the newer techniques of diagnosis and measurement; spectro- scopy in all its forms X-ray techniques gas chromatography electron-spin resonance nuclear magnetic resonance etc. Consciously or unconsciously they wished to keep the analytical chemist in his place and it happened to be his pre-1920 place! Many of the techniques in use today did not originate in analytical chemistry nor were they first applied by analytical chemists. But he believed with Liebhafsky that “like it or not the chemistry is going out of analytical chemistry” and that whatever it might be called its objective today was the characterisation and control of materials.If the analyst was to survive he must be on the alert to capture and to harness and sometimes to lay claim to any new technique that would help him to realise this new and wider conception of the objects and purpose of what for want of a better name was still called analytical chemistry. There was a challenge here and a need. A need to establish the closest contacts with those working in the newer fields of August 19661 PAPERS ACCEPTED FOR PUBLICATION 131 measurement and a need for a mechanism for collaboration during this period of transition from classical analytical chemistry to something based more broadly on other types of measure- ment and in which elemental composition was but one and sometimes the minimal require- ment. It was not uncommon today for example to find materials that were the basis of very conventional chemical method of examination appeared to be identical and yet behaved quite differently in some modern industrial applications.It was not surprising to find that it was in the research laboratories of some of the major industrial companies that there had evolved a conceptual analytical unit whose functions and objectives reflected the trends he had been trying to depict. In the G.E.C. Laboratories they had been following this philosophy over a very long period; for example emission spectroscopy and X-ray crystal analysis were two of the analytical tools in use for well over thirty years. It was significant to note that at the National Bureau of Standards in Washington the Analytical Division comprised seven sections and embraced thirty analytical “competences.” He was concerned to see that the “analyst” did not allow either natural conservatism in his own ranks or the unwarranted influence of scientific zealots who were both intolerant and ignorant of worthwhile disciplines other than their own highly specialised activity to damage his image and label him as intellectually and socially second-rate.The President in his closing remarks expressed the gratitude of the Society to all con- cerned with and participating in the Meeting. Papers Accepted for Publication in The Analyst THE following papers have been accepted for publication The Analyst and are expected to appear in the near future. “Activation Analysis of Titanium and Niobium with Fast Neutrons,” by V. T. Athavale “The Spectrophotometric Determination of Trace Amounts of Tantalum,” by J.H. Hill. “Dimethoate Residues in Fruits and Vegetables An Assessment of Methods of Analysis,” “Specific Spot Tests for Silver Cyanide,” by F. Feigl and A. Caldas. “On the Organic-phase Spectrophotometric Determination of Iron,” by E. Cerrai and G. Ghersini. “Determination of Specific Gravity of Glass Particles by a Density Gradient Method,” by S. S. Kind and L. Summerscales. “Spectrophotometric Determination of Vitamin D in Fresh-water Fish Liver Oils,’’ by R. K. Barua and M. V. K. Rao. “Rapid Determination of Molybdenum in Alloy Steels by Atomic-absorption Spectroscopy in a Nitrous Oxide -Acetylene Flame,” by G. F. Kirkbright A. M. Smith and T. S. West. “An Injection Tap for Gaseous Samples in Gas -Solid Chromatography,” by F. G. Stanford. “The Proportion of 2-Methylbutanol and 3-Methylbutanol in some Brandies and Whiskies as Determined by Direct Gas Chromatography,” by D. D. Singer. “The Determination of Acinitrazole,” a Report prepared by the Prophylactics in Animal Feeds Sub-committee of the Analytical Methods Committee. H. B. Desai S. Gangadharan M. S. Pendharkar and M. Sauker Das. by N. A. Smart.

ISSN:0037-9697    

DOI:10.1039/SA9660300129

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

132 SPECIAL TECHNIQUES IN GAS ANALYSIS [Proc. SOC. AnaZyt. Chem Special Techniques in Gas Analysis The following are summaries of papers presented at the meeting of Special Techniques Group on February 22nd 1966 and reported in the April issue of Proceedings (p. 51). Thermovapourimetric Analysis BY B. RILEY (Metallurgy Division Atomic Enevgy Reseavch Establishment Havwell Didcot Berks.) MR. RILEY defined thermovapourimetric analysis as an analytical technique in which gaseous products of decomposition or reaction evolved when a substance was gradually heated in a ceramic tube were continually recorded as a function of temperature. Firstly there might be physical changes in the form of thermal expansion sintering grain growth crystallographic phase changes or desorption of gases. Secondly there might be chemical changes arising from the reaction of the components or decomposition in which one or more products was a gas.Thermovapourimetric analysis was concerned with determining adsorbed and absorbed gas and gaseous products of reaction the rate at which these gases were evolved and the temperature of evolution. The experimental apparatus for thermovapourimetric analysis of solid materials with a discharge tube as detector and argon as carrier gas was discussed although other types of furnaces detectors and carrier gases could be used. If a specimen was heated in a gas-tight tube under a flow of carrier gas (the purity of which was measured by the detector and continuously recorded as the temperature increased) gaseous products were injected into the carrier-gas stream.Under these conditions the system behaved as a differential analyser the height of the peak traced out by the recorder (thermovapourgram) was proportional to the rate of gas evolution; the area under the curve was proportional to the volume of gas evolved. The types of reactions most suitable for investigation by thermo- vapourimetric analysis were as follows. Several changes could occur on heating a substance. Simple thermal decomposition e.g. CaCO -+ CaO + CO 1' 2UH3 -+ 2U + 3Hz 1' Stage dehydration and dec.omposition e g . FeS0,.7H20 -+ FeS0,.3H20 + 4H,O f -+ FeSO + 3H,O -+ 'FeS + 20 Adsorbed - absorbed - chemically bound gases e g . Thermal decomposition of the clay Silklay CLAY -+ ABSORBED H2O (-40" -+ - 10" C) ADSORBED H,O (80" -+ 110" C) CHEMICAL H,O (400" -+ 500" C) Gaseous diffusion e.g.the diffusion of oxygen through a ceramic tube at high temperatures with an oxygen analyser (Hersch cell) as detector. Solid-state reactions e.g. carbothermic reduction of the oxides to form carbides or metals. Fe,O + 3C -+ 2Fe + 3CO f (CO,) uo,+3c -+ UC+2COf August 19661 SPECIAL TECHNIQUES I N GAS ANALYSIS 133 (f) Gaseous reduction e g . the reduction of oxides in hydrogen. Dry hydrogen used as a carrier gas the water formed on reduction was determined with a moisture meter (Elliot). U,O + 2H2 -+ 3U02 + 2H20 /r (g) Gaseous oxidation e.g. The determination of trace radioactive gases or fission products e.g. the determination of trace carbonaceous matter as CO,. detected with a katharometer. The CO was (h) the release of radon from minerals failure of coated micro spheres at high temperatures.The radioactive gases were detected with either a Geiger counter or mass spectroscope. This was only a brief survey of the possible uses of thermovapourimetric analysis; the technique could be used whenever a reaction took place in which one or more of the products was a gas. Although the list illustrated the decomposition or reaction with increasing temperature agents other than temperature could be used e.g. the decomposition under irradiation; the formation of oxygen or carbon dioxide in biological systems under various wavelengths of light ; oxygen diffusion through membranes with time or moisture. DETECTORS The choice of a detector for use in thermovapourimetric analysis depended upon the nature of the products of decomposition and how they differed in physical and chemical properties from those of the carrier gas.Detectors used in the field of gas chromatography could be used in thermovapourimetric analysis. The criteria of a good detector in thermo- vapourimetric analysis were that the detector should give a linear recordable output preferably in the range 0 to 10 or 0 to 100 mV; the background noise and base-line drift should be less than 1 per cent. of full-scale deflection the stability and sensitivity should be high enough to detect minor reactions without the need for large sample weights; and the gas sample flow- rate through the detector should be small enough not to over-dilute the reaction products yet large enough to give rapid response time. A convenient arbitrary flow-rate through a furnace tube could be taken as the flow to give at least 5 changes of atmosphere per minute the detector had to have at least this volume changes per minute or could detect changes every 10 seconds.LOW TEMPERATURE AND LOW PRESSURE VAPOURGRAMS- The flow of a dry carrier gas over a specimen at room temperature gradually removed the adsorbed vapours or water of crystallisation of hydrates of high vapour pressure. To detect these gaseous species the vapourgram could be commenced not at room temperature but at that of liquid air (- 100" C) or solid CO (-50" C) by cooling the entire furnace down to these temperatures. With the arrangement of the carrier gas over the specimen being at atmos- pheric pressure saturation by water vapour by hydrates decomposing was the most stringent limitation because the detector output deviated from a linear relationship owing to con- densation- evaporation of the water on colder parts of the tube and detector inlets.To overcome this disadvantage the entire furnace tube was evacuated to a pressure low enough to prevent condensation (20 mm of mercury) while the discharge tube was used as detector. This arrangement greatly increased the sensitivity of the apparatus the furnace and the discharge tube being virtually a single detector unit. IDENTIFICATION OF SPECIFIC PEAKS IN A VAPOURGRAM- In using a "total" detector in which all gases injected into a carrier gas stream were recorded there was no indication as to which gas species the various peaks on the vapourgram belonged. By using a specific detector Hersch cell (oxygen) moisture cell (water) jn con- junction with a total detector Argon purity meter it was at least possible to identify specific gases.With the increasing interest shown in carbides both as a structural and nuclear materials in the course of fabrication it had become necessary to identify such gases as carbon dioxide hydrogen methane and higher hydrocarbons. The thermal decomposition 134 SPECIAL TECHNIQUES IN GAS ANALYSIS [Proc. Soc. Analyt. Chewz. of minerals required the knowledge of gaseous products containing carbon dioxide carbon monoxide sulphur dioxide possibly organic fractions and adsorbed gases such as helium and radon. If a sample of the carrier gas at peak height was injected into a gas-chromatography column identification of a number of gases could be obtained by measuring the retention time on the column.The speaker then discussed the combination of thermovapourimetric analysis with other analysis techniques and considered the following examples. (a) The combination of thermovapourimetric analysis with a recording dilatometer to analyse shrinkage compaction or sintering with gaseous reactions. ( b ) Thermovapourimetric analysis and differential thermal analysis could be used to determine the heats of reaction involved in gaseous decomposition. (c) Thermovapourimetric analysis and X-ray diffractometer combined the gaseous analysis with the identification of the solid phases present. (d) Thermovapourimetric analysis with thermogravimetric analysis with specific detectors or gas chromatography could be combined to give a useful tool in thermal decomposition analysis. Mr.Riley concluded by mentioning the factors that could affect the shape reproducibility resolution and interpretation. These were temperature programming; rate of temperature increase ; sample weight ; carrier-gas flow-rate through furnace and detector ; carrier-gas pressure; and geometric factors such as response time. Some Aspects of Gas Analysis with Gas - Solid Chromatography By C. G. SCOTT (Buvmah Oil Trading Ltd. Lobitos Refinery Ellespnere Port Wivral Cheshire) DR. SCOTT commenced by describing recent advances in the separation of permanent gases by using active solids; these included the separation of the stable hydrogen isotopes and their spin isomers with a capillary column (E. Mohnke and W. Saffert in M. van Swaay Editor “Gas Chromatography 1962,” Butterworths 1963 p. 216) and the potential application of porous polymer beads (0.L. Hollis Analyt. Chewz. 1966 38 309) for the analysisof gases containing water vapour. The recent work of R. Aubeau et al. ( J . Chromatog. 1965 19 249) was used to illustrate how the state of activation of the column packing affected relative retentions even for the comparatively simple permanent gas separations. Attention to experimental detail was emphasised. Dr. Scott then described the techniques of frontal and displacement analysis and although the applications cited were concerned with organic vapours their use for attacking problems encountered by the gas analyst was envisaged. The variation of frontal analysis in the form of vacancy chromatography (A. A. Zhukhovitski iut A. Goldup Editor “Gas Chromatography 1964,” Institute of Petroleum 1965 p.161) was discussed at length and the potential in conjunction with porous polymer bead packing for continuous on-stream analysis of process gases containing water vapour was considered. A use of vacancy chromatography which had not been verified experimentally but which did not seem unreasonable was when two adjacent elution peaks over-lapped because one of them was present in much greater proportion than the other. With vacancy chromatography under the correct conditions an injection of sample containing the major component in approximately the same concentration as in the process stream should result in a chromatogram showing 2 separated vacancy peaks one for the minor component and one for the difference between the concentration of the major component in the process stream and the injected sample.Thus an indirect analysis of the process stream could be obtained which was not feasible by normal elution chromatography. Finally Dr. Scott described the recovery by displacement chromatography of traces of organic compounds selectively concentrated on an active solid (C. G. Scott andC. S. G. Phillips in A. A. Zhukhovitski 09. cit. p. 266) with its potential for recovering sufficient trace material e.g. carcinogenic hydrocarbons from the atmosphere for conventional gas - liquid elution separation in amounts sufficient to allow confirmative identification tests to be applied to the separated components. August 19661 SPECIAL TECHNIQUES I N GAS ANALYSIS 135 The Determination of Trace Impurities in Permanent Gases with a Mass Spectrometer BY R.E. WILSON AND R. T. PARKINSON ( A .M.G.(O) Chemical Inspectoyate Headquavtevs Buildings Woolwich Avsenal Londouz S.E.18) MR. WILSON said that conventional mass-spectrometric analysis for trace impurities in gases was limited to about 20 to 50 p.p.m. by volume. It had been shown that by increasing the source pressure the detection limits could be reduced to the 1 p.p.m. by volume level without a serious loss in resolution. However with the large increase in through-put of gas it was necessary to “blow the liquid nitrogen trap” on the mercury diffusion pump at about monthly intervals because of loss of pumping speed. The gain in sensitivity had been shown to be inversely proportional to the molecular weight of the gas except for helium for which ex- ceptional sensitivity was found.A dynamic gas sampling and inlet system had been devised to take advantage of the improved sensitivity. By operating at about 1000-torr. pressure with gas flowing at not less than 2 litres per minute past the leak the effects of sorbed impurities could be overcome analyses could be repeated easily the establishment of equilibrium conditions checked and the number of analyses completed per day greatly increased. This system had been applied in particular to the routine analysis of hydrogen helium and argon as cylinder gases for impurities including where appropriate hydrogen nitrogen helium argon carbon dioxide and oxygen. The only serious interference effect noted was in determining oxygen in hydrogen ; conditioning was protracted and the sensitivity reduced relative to oxygen in helium.The preparation of suitable standards for analysis in this region necessitated the supply of a pure base gas and a gas blender. The gas either helium or hydrogen was purified to less than 1 p.p.m. by volume of impurity excluding neon and water vapour (the latter was not measured) by passage through a bed of activated charcoal or Spheron carbon at a temperature of 77” K. This purified gas was passed through the blender and then to the dynamic inlet system at a controlled flow-rate and pressure. The impurity was injected into the pure gas stream through a capillary (30 cm x 0.004 cm) from a reservoir; impurity levels in the range 3 to 500 p.p.m. by volume were obtained dependent upon the operating conditions. Con- centrations down to 0.05 p.p.m. by volume could be obtained if the impurity gas was replaced by a 1 per cent.mixture of the impurity in the base gas. The capillary characteristics for each impurity gas were determined separately and hence the impurity concentratian could be calculated. This technique at present gave only binary mixtures and at the low impurity concentration levels used it was considered that interference of one impurity with another in the dynamic inlet system was negligible. A multi-component blender was under construction and it was hoped that the possible interference of one impurity with another could be further investigated. Separate analyses of prepared blends for oxygen and carbon dioxide showed that the accuracy and precision of the blender were adequate. The utility of separation techniques involving either “liquefaction” or “freeze-out” (Analyst 1965,90,220) for about 1 p.p.m.by volume of carbon dioxide in nitrogen or hydrogen hydrogen in argon and nitrous oxide in nitrogen and hydrogen was described. Again as the dynamic inlet system operated at above atmospheric pressure it had been possible to couple a gas chromatograph comprising a temperature-controlled molecular sieve 5A column and helium ionisation detector to the mass spectrometer and determine for example 0.1 p.p.m. by volume of oxygen and argon in nitrogen less than 0-5 p.p.m. by volume of oxygen in hydrogen and less than 0.5 p.p.m. by volume of carbon monoxide in nitrogen. Finally the continuous analysis of hydrogen for about 5p.p.m. by volume of helium nitrogen for less than 1 p.p.m. by volume of each of helium and hydrogen and carbon dioxide for less than 0-5 p.p.m. by volume of nitrogen less than 0-5 p.p.m. by volume of oxygen less than 0.1 p.p.m. by volume of hydrogen was described in which the base gas was continuously removed on the low pressure side of the mass-spectrometer inlet leak either by sorption or deposition as solid and analysis of the volatile residue,

ISSN:0037-9697    

DOI:10.1039/SA9660300132

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

136 NEW ASPECTS OF INFRARED SPECTROMETRY [Proc. Soc. AnaZyt. Chew. New Aspects of Infrared Spectrometry The following are summaries of papers presented at a Meeting of the Special Techniques Group held on March 22nd 1966 and reported in the May issue of Proceedings (p. 70). Far Infrared Spectroscopy and Some Applications BY A. E. MARTIN (Sir Howard Grubb Parsons G. Co. Ltd. Walkergate Newcastle @on Tyne 6) DR. MARTIN said that spectrometers operating up to 50 p presented no special problems coarse gratings were used and for order selection a small caesium iodide prism or interference filters could be used. Beyond 50 p conditions were unfavourable because of low energy from available sources and lack of suitable prisms and interference filters. The source size could be increased slits were made larger and the Golay detector with its larger receiving area was used.Order rejection was obtained with a variety of filtering means the most important being selective reflection from crystal plates (Reststrahlen) and crystal chopping (potassium bromide chops only required longwave radiation). Beckman and Perkin - Elmer manufactured expensive double-beam instruments that extended the useful range to beyond 300 p but lack of energy was still troublesome. Sir Howard Grubb Parsons & Co. Ltd. produced a simple and in- expensive single-beam spectrometer for use in the region 50 to 150 p in which the background was maintained a t a reasonably constant level by programming the slits and removing intensely absorbing water vapour. As an alternative to the conventional instrument the interferometric spectrometer was now available and was particularly suitable for use at long wavelengths.A variety of the Michelson interferometer was used and the output signal which constituted an interferogram was punched out on paper tape at discrete intervals of path difference. The Fourier transform of the interferogram was the power spectrum and was obtained with the help of a digital computer. The ratio of 2 such spectra (background and background @us sample) was determined in the computer to give the familiar transmittance spectrum. APPLICATIONS- Pure rotation spectra of many of the smaller molecules were found in the longwave region while vibrational frequencies could be observed when heavy atoms or weak force constants were involved e.g. a sharp band a t 110.8 cm-l occurred in iodoform and the "butterfly flapping" frequency of naphthalene was found at 178 cm-l (160 on deuteration) ; organometallic and related complexes often had useful spectra.Torsional frequencies could be observed and potential barriers restricting internal rotation were investigated. Torsional modes in long-chain paraffins were normally inactive but the introduction of a polar group such as C=O induced absorption. Polythene was generally transparent but absorption occurred at 73 cm-l and its intensity was directly related to density. Lattice vibrations provided a rich field of investigation and a simple example was given by crystalline hydrochloric acid condensed on a substrate. Many ionic crystals had an intense transverse optic mode occurring at a somewhat lower frequency than the Reststrahlen value (165 and 195 cm-l for sodium chloride).Sapphire exhibited striking absorption changes (0 to beyond 300 cm-l) when the temperature changed from 100" to 300" K. Covalent bonds in diamond germanium and silicon were associated with low absorption provided that the material was pure. Introduction of impurities might produce semi-con- ductors with increased absorption which could be studied with or without an applied magnetic field. Recent work at the National Physical Laboratory had produced interesting spectra of crystalline benzene - chloroform mixtures at 170" K quite different from those given by the separate components. An intense CF2 rocking frequency at 200 cm-l was found in PTFE. August 19661 NEW ASPECTS OF IMPROVED SPECTROMETRY 137 Infrared Spectroscopy with Attenuated Total Reflection BY A.C. GILBY (Molecular Science Division National Physical Laboratovy Teddington Middlesex) DR. GILBY said that attenuated total reflection (A.T.R.) was a relatively new sampling technique for obtaining high contrast spectra of materials in condensed phases. So far most of the development had been in the infrared. Although A.T.R. spectroscopy (also known as internal reflection spectroscopy) involved the use of extra spectrometer attachments there were several instances in which the technique offered advantages or gave information about the sample not readily obtainable by con- ventional absorption techniques. Dr. Gilby went on to explain the main differences between an internal reflection spectrum and the corresponding absorption spectrum and how by choosing properly the A.T.R.equipment internal reflection spectra could be obtained that did not show the badly distorted band shapes so often seen. An A.T.R. spectrum was obtained by placing the sample in contact with a material of high refractive index pz, (the A.T.R. crystal). Commonly used materials were KRS-5 (pz = 2.4) germanium (pz = 4) and silver chloride (pz = 2). A beam of light was directed through the A.T.R. crystal so that it was reflected once or many times at the boundary with the sample at an oblique angle of incidence 8 (measured from the normal to the interface). A scan of the intensity of the reflected light versus wave-number produced the internal reflection spectrum. There were important differences between internal reflection spectra and con- ventional absorption spectra.An absorption spectrum of a pure substance depended essen- tially upon its thickness and on its absorption coefficient a. (I/I, = e-al). Internal reflection spectra were more complicated and the attenuation of the reflected light beam depended on the two optical constants of the sample as well as on pz and 8,. These optical constants were known as the real part pz and the imaginary part n K of the complex refractive index = n(1 + iK) where i = 2/5. The term p z ~ was also called the extinction coefficient and was related to a by a = 4npz~/h where h is the vacuum wavelength of the light. The shape of internal reflection bands could be successfully explained by the following simplified arguments a t a frequency where the sample was transparent values of 8 and n1 were chosen so that the beam of light was totally internally reflected at the boundary with the sample.Under these conditions a light wave existed for a short distance into the sample (the order of a wavelength beyond the boundary but depending on several factors). Energy could be lost from the reflected beam either 1 (i) if n approached the value of pz,sinB the extent of the penetration into the sample increased rapidly. 1 (ii) if at some parts of the spectrum the value of pz increased so that it exceeded the value of pz,sinB, light was transmitted and lost into the sample; 2 if the sample absorbed at a particular frequency the sample trapped light energy from the penetrating wave at this frequency. If A.T.R. spectra showing well-defined undistorted absorption-like bands were required it was necessary to eliminate as far as possible effects 1.This was achieved by ensuring that Yt,sinB was always substantially larger than n. Unfortunately as n,sinB increased the extent of the penetration of the light into the sample was unavoidably decreased so producing a too-weak spectrum. This difficulty could be overcome by using a multiple reflection tech- nique to build up the strength of the reflection bands; this was analogous to using a thicker sample in a transmission experiment. Many A.T.R. spectra frequently those obtained with a single-reflection attachment showed bands that were broadened on the low-frequency side and with the peak shifted to lower frequencies relative to the absorption spectrum. This was because wherever in the spectrum there was a peak in I$K the TZ of the sample went through an oscillation.The pz was high on the low-frequency side of the band centre and low on the high-frequency side. The distortion was then understandable in terms of effects 1. Because of the relation a = 4 ~ n ~ t ~ / h an internal reflection spectrum always showed bands which by comparison with the absorption spectrum were relatively weaker at the high-frequency end of the s?ectrurn. By Snell’s Law n,sinB > n. This has important effects only when the sample absorbed (see 2); 138 PUBLICATIONS RECEIVED [Proc. SOC. ANalyt. Chem. An entirely separate use of A.T.R. was in the precise determination of the optical constants of the sample n and TzK. A high-speed digital computer was used to analyse the complicated reflection-band shapes obtained when the refractive-index effects were not suppressed. Dr. Gilby referred to work reported by J. Fahrenfort (Spectrochim. Acta 1961 17 698) J. Fahrenfort and W. M. Visser (Ibid. 1962 18 1103) W. N. Hansen (Ibid. 1965 21 815) P. A. Fluornoy (Ibid. 1966,23 5) N. J. Harrick ( J . Opt. SOC. Amer. 1965,55 851) and A. C. Gilby J. Burr W. Krueguer A. A. Clifford and B. Crawford ( J . Phys. Chem. 1966,70,1520). Dr. Gilby said that the explanation of A.T.K. band shapes came from the results of unpublished work at the Molecular Spectroscopy Laboratory Dept. of Chemistry University of Minnesota Minneapolis Minnesota U.S.A. in collaboration with J. C. Burr jun. and Professor Bryce L. Crawford jun.

ISSN:0037-9697    

DOI:10.1039/SA9660300136

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

138 PUBLICATIONS RECEIVED [Proc. SOC. ANalyt. Chem. Publications Received The publications listed below have been received by the Editor of The Analyst in which journal Book Reviews will continue to appear. By Dr. HANS SIEBERT. Pp. viii + 209. Berlin Heidelberg and New York Springer-Verlag. 1966. Price DM39.60. London The British Medical Association and The Pharmaceutical Society of Great Britain. Price 12s. 6d. (Interleaved with plain paper 22s. 6d.). CHEMICAL ANALYSIS IN PHOTOGRAPHY. By G. RUSSELL A.R.P.S. F.R.I.C. Pp. 272. London and New York The Focal Press. 1966. Price 90s. VISUAL METHODS OF EMISSION SPECTROSCOPY. Translated by IPST Staff. Pp. viii + 344. Jerusalem Israel Program for Scientific Translations. Distributed in Great Britain and the Commonwealth South Africa Eire and Europe by the Oldbourne Press London.1965. Price 108s. Pp. ii + 82. New York The Farday Press Inc. 1966. Price (single issue) $35; Annual Subscription $120. A New Journal. Pp. xiv + 143. 1966. Price 28s. INTERPRETIVE SPECTROSCOPY. Edited by STANLEY K. FREEMAN. Pp. vi + 295. New York Reinhold Publishing Corporation; London Chapman & Hall Ltd. ANALYSIS INSTRUMENTATION-1965. Proceedings of Eleventh Annual Analysis Instrumentation Symposium held May 26-28 1965 at Montreal P.Q. Canada. Edited by L. FOWLER R. G. HARMON and D. K. ROE. Pp. viii + 240. New York Plenum Press. Price $12.50. LECTURES ON MATTER EQUILIBRIUM. By TERRELL L. HILL. Pp. xii + 306. New York and Amsterdam W. A. Benjamin Inc. 1966. Price $6.00. KINETIC THEORY OF GASES. THERMAL PROPERTIES OF MATTER. Volume 1. By WALTER KAUZMANN.Pp. xiv + 248. New York and Amsterdam W. A. Benjamin Inc. 1966. Price $7.70. By C. J. NYMAN and G. B. KING. Pp. x + 273. New York London and Sydney; John Wiley and Sons. 1966. Price 23s. ANALYTICAL CHEMISTRY OF POTASSIUM. By L. M. KORENMAN. Pp. vii + 242. Jerusalem Israel Program for Scientific Translations. Distributed in Great Britain and the Common- wealth South Africa Eire and Europe by the Oldbourne Press London. 1966. Price 99s. By S. V. ELINSON and K. I. PETROV. Pp. x + 206. Distributed in Great Britain and the Commonwealth South Africa Eire and Europe by the Oldbourne Press London. 1966. Price 81s. ANWENDUNGEN DER SCHWINGUNGSSPEKTROSKOPIE IN DER ANORGANISCHEN CHEMIE. BRITISH NATIONAL FORMULARY 1966. Pp. 360. 1966. By N. S. SVENTITSKII. THEORETICAL AND EXPERIMENTAL CHEMISTRY. Editor-in-Chief K. B. YATSIMIRSKII. ANALYTICAL CHEMISTRY OF SELECTED METALLIC ELEMENTS. By JAMES J. LINGANE. New York Reinhold Publishing Corporation; London Chapman & Hall Ltd. 1966. Price 140s. PROBLEMS FOR GENERAL CHEMISTRY AND QUALITATIVE ANALYSIS. ANALYTICAL CHEMISTRY OF ZIRCONIUM AND HAFNIUM. Jerusalem Israel Program for Scientific Translations.

ISSN:0037-9697    

DOI:10.1039/SA9660300138

出版商:RSC    

年代:1966

数据来源: RSC