摘要:

MAY, 1963 THE ANALYST Vol. 88, No. 1046 EDITORIAL Development of The Analyst IN February of this year the Council of the Society recei\Ted and-except for one matter whose implement ation required further consideration-approved a report from the Analyst Development Committee. This Committee had, olw- a period of just on two years, studied criticisms of The Analyst and suggestions for changes in its contents and format. It began by inviting members and subscribers, both through a general announcement in the Bulletin and by direct personal invitation to members known to hold decided views, to submit their ideas. Thereafter a round dozen were interviewed singly or in small groups, and what they had to say was discussed and recorded in a detailed summary of evidence : this record alone eventually occupied 60 pages of close-spaced typescript.When the points made at these meetings had been marshalled into some sort of order, a document was drawn up for the Committee to consider in greater detail than had been possible while the ideas were still being put forward. By this stage the Committee had had much valuable discussion with the propounders of the ideas, and it was clear that on some matters there were as many views as critics, and most of them contradictory. But some points of agreement (though never unanimous) had appeared. The members of the Develop- ment Committee, too, put forward their own suggestions, and the two written contributions that had been received were also considered. The outcome of the Committee’s investigations and deliberations was the presentation to council of 35 recommendations for positive actions that the Committee unanimously believed would enhance the reputation and status of The *4 natyst.As might be expected, it took longer to consider the criticisms and tveigh the suggestions than it had to make them, and during this time some of the less controversial matters were referred to Council, received favourable decisions and were implemented. Already the appearance of the journal has been improved by starting each paper on a new page and by using a modern white paper in place of the older style cream-tinted paper for the text. The second of these changes was made only after the Committee had considered specimen pages printed on eight different papers and had compared them with other journals; even then the final choice was not endorsed until tests by PATKA had shown that the new paper was in many respects technically superior to the old, and inferior in none.But other suggestions, such as changing the size of the page or altering the size of the type, were found to have positive disadvantages and were rejected, and suggestions that the number of pages in each issue should be increased, although they were sympathetically received, can only be imple- mented when the rate of inflow of papers has permanently increased. It appeared that some misconceptions might prevail as to the range of subjects con- sidered suitable for publication in The Analyst, and as to whether there were any restrictions on authorship. The Committee hoped that removal of these misconceptions would result in more papers being offered, and to this end they have revised the “Notice to Authors.” The newversion, printed on p.409, has a preamble intended to convey the information that The Analyst caters for all types of paper on the theory and practice of analytical chemistry, provided only that they reach a satisfactory standard of quality. Reviews, fundamental work, descriptions of specialised techniques and applications of existing methods in new contexts-all are essential to a properly balanced journal. The Analyst is, too, an international journal-a recent survey showed no less than a third of the contributions to be from overseas- 331332 PR0CEE:DINGS [Analyst, Vol. 88 and the Editors are, when necessary, ready and willing to assist authors whose natural tongue is not English with the presentation of their papers.Nor do authors need to be members of the Society-roughly twice as many papers are accepted from non-members as from members (of course, membership of the Society has many other advantages). Some anxiety had been expressed to the Development Committee about the refereeing system for papers. Much of this proved to be due to a lack of information on the subject; the Committee concluded that not only had the system to be fair (which it was), but that it had to be seen to be fair (which was much more difficult to arrange). Previously, acceptances have been based on a single referee’s report, whereas rejections have required two or more adverse reports, obtained seriatim at much expense of time.In future all papers will be sent simultaneously to two referees; if their reports concur, final decisions will be made at once by the Editorial Committee, and if the original reports differ, the Committee will itself select a third referee as arbiter and make its decision only after receiving the third report. The two primary referees will be selected from the existing comprehensive panel of over 200, plus the additions that are constantly being made; this system will be much more rapid, if slightly more mechanical, than hitherto. Its functions include the supervision of all aspects of production of The Analyst. But the old Publication Committee’s responsibility for policy has been transferred to a new Publications Policy Com- mittee. This move is in keeping with the increasing number and scope of the Society’s publications, which include, besides The Analyst and Analytical Abstracts, Monographs, collections of Standard Methods, publications by the Analytical Methods Committee and sundry volumes of Symposium and Congress Proceedings. It is indeed to this Publications Policy Committee that Council has passed, for urgent attention, the question of implementing the excepted recommendation mentioned in the first sentence of this editorial. Although the Development Committee has successfully planned its own demise, it has left a more permanent successor on which will rest the responsibility for further development of The Analyst. Even now, only half of the Development Committee’s recommendations have been implemented, and an account of some of the remaining decisions must await a future occasion. The Editorial Committee is, basically, the former Publication Committee.

ISSN:0003-2654    

DOI:10.1039/AN9638800331

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

332 PR0CEE:DINGS [Analyst, Vol. 88 PROCEEDINGS OF THE SOCIETY FOR ANALYTICAL CHEMISTRY ANNUAL GENERAL MEETING THE eighty-ninth Annual General Meeting of the Society was held at 2.15 p.m. on Friday, March 8th, 1963, in the meeting room of the Royal Society, Burlington House, London, W.l. The Chair was occupied by the President, Dr. A. J. Amos, O.B.E., B.Sc., F.R.I.C. The Financial Statement for the year ending October 31st, 1962, was presented by the Honorary Treasurer and approved, and the Auditors for 1963 were appointed. The report of the Council for the year ending March, 1963 (see pp. 334343), was presented by the Honorary Secretary and adopted. The Scrutineers, Messrs. P. W. Shallis and K. L. Smith, reported that the following had been elected officers for the coming year- Presidefit-D.C. Garratt, Ph.D., D.Sc., Hon. M.P.S., F.R.I.C. Past Presidents serving on the Cou.nciZ-A. J. Amos, R. C. Chirnside, J. H. Hamence and Vice-Presidents-S. G. Burgess and R. E. Stuckey. Honorary Treasurer-D. T. Lewis. Honorary Secretary-S. A. Price. Honorary Assistant Secretaries-C. A. Johnson (Programmes Secretary) and D. W. Wilson. Other Members of CounciZ-The Scrutineers further reported that 143 valid ballot papers had been received. As the number of candidates for election as Ordinary Members of Council had been equal to the number of places to be filled, there had been no ballot for their election. The President declared the following to have been elected Ordinary Members of Council for the ensuing two years-L. Brealey, A. G. Jones, E.Q. Laws, F. C. J. Poulton, S. G. E. Stevens and C. Whalley. K. A. Williams.May, 19631 PROCEEDINGS 333 H. E. Brookes, P. F. S. Cartwright, B. S. Cooper, J. F. Herringshaw, R. M. Pearson and A. A. Smales, having been elected members of the Council in 1962, will, by the Society’s Articles of Association, remain members of the Council for 1963. C. J. House (Chairman of the North of England Section), R. A. Chalmers (Chairman of the Scottish Section), F. H. Pollard (Chairman of the Western Section), W. H. Stephenson (Chairman of the Midlands Section) , D. W. Wilson (Chairman of the Microchemistry Group) , W. Cule Davies (Chairman of the Physical Methods Group) and W. A. Broom (Chairman of the Biological Methods Group) will be ex-officio members of the Council for 1963.The retiring President, Dr. Amos, thanked the Honorary Officers for their services to the Society during his term of office. He then formally installed Dr. Garratt, who for many years has been Chairman of the Analytical Methods Committee, as President. After the business outlined above had been completed, the meeting was opened to visitors, and the retiring President delivered his Presidential Address (see pp. 346351). ORDINARY MEETING L 4 ~ Ordinary Meeting of the Society was held at 6.30 p.m. on Wednesday, May lst, 1963, at University College, Gower Street, London, W.C.l. The Chair was taken by the President, Dr. D. C. Garratt, Hon.M.P.S., F.R.I.C. The following paper was presented and discussed : “The Use of Magnetic Resonance Measurements in Chemistry,” by Professor R.S. Nyholm, M.Sc., Ph.D., DSc., F.R.A.C.I., F.R.I.C., F.R.S. MIDLANDS SECTION THE Eighth Annual General Meeting of the Section was held at 7 p.m. on Thursday, March 28th, 1963, at the Nottingham and District Technical College, Burton Street, Nottingham. The Chair was taken by Mr. W. T. Elwell, F.R.I.C. The following appointments were made for the ensuing year :-Chairman-Mr. W. H. Stephenson. Vice-Chairman-Mr. W. T. Elwell. Hon. Secretary-Mr. M. L. Richardson, John & E. Sturge Ltd., Lifford Chemical Works, Lifford Lane, Kings Norton, Birmingham 30. Hon. Treaswer-Mr. F. C. J. Poulton. Hon. Assistant Secretary-Mr. R. Adkins. Members of Committee-Prof. R. Belcher, Dr. R. G. H. B. Boddy, Mr. H. E. Brookes, Mr. W. M. Dowson, Mr. G. Ingram, Mr. N. Nix, Mr. D. M. Peake, Dr. H. C. Smith (ex-oficio for 1 year) and Mr. C. Whalley. Miss M. E. Tunnicliffe and Mr. J. Blenkin were re-appointed as Hon. Auditors. The Annual General Meeting was followed by an Ordinary Meeting of the Section when the following paper was presented and discussed: “Reactions in Non-aqueous Solutions” by Dr. L. D. Pettit.

ISSN:0003-2654    

DOI:10.1039/AN9638800332

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

334 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 [ATZabSt, vol. 88 Annual Report of the Council: March, 1963 IT has become customary in recent Annual Reports of Council to record and comment on the increasing activities of the Society. During the present year these activities have at least been maintained. For the second time in recent years the Society’s Annual General Meeting--the eighty- eighth-was held outside London. At the invitation of the North of England Section, both the Annual General Meeting and the Bernard Dyer Memorial Lecture were held in Manchester, and Dr. D. W. Hill gave an address entitled “Research and the National Economy.” Again, as in Birmingham two years previously, the lecture was well attended, including a substantial proportion of members from outside the North of England Section; the lecture was followed in the evening by the Society’s Annual Dinner, again well attended by members from all parts of the country.Although the report of the Midlands Section, given separately, refers to the Feigl Anni- versary Symposium held in Birmingham in April, 1962, it is appropriate to mention it here. The Symposium was held in the Chemistry Department of the University of Birmingham and organised on behalf of the Society by the ‘Midlands Section. Speakers and delegates from 28 countries-to a total of 400-attended to hear lectures, to join the discussions and to pay tribute to Professor Fritz Feigl. The Microchemistry Group, through their Chairman, Mr. C. Whalley, also paid tribute, from the microchemists of the United Kingdom, with the presentation of a magnificent glass vase.This Symposium is yet another in the line of successful Symposia organised at Birmingham by the Midlands Section, and all involved deserve cordial thanks for their work. The Sections and Groups have again been active and meetings have been as frequent and widespread as in previous years. The Scottish Section organised a meeting, jointly with the North of England Section and at the invitation of the Chemistry Department of Queen’s University Belfast, on a range of physico-chemical methods of analysis. In September the Microchemistry Group held a joint meeting with the Dublin and District Section of the Royal Institute of Chemistry in Trinity Hall, Dublin, the title being “Modern Trends in Small Scale Inorganic Analysis.” The year was noteworthy in that the Physical Methods Group set up an Atomic Absorption Spectroscopy Discussion Panel with Mr.W. T. Elwell as Chairman and Mr. D. Moore as Honorary Secretary; the Panel held its inaugural meeting on December 12th, 1962, at which a paper entitled “Aspects of Atomic Absorption Analysis’’ by D. J. David, MSc., was read. The Council wishes success to the Physical Methods Group in this venture. The annual conference of Honorary Secretaries was held somewhat earlier than usual, in January. In addition to the usual meeting, an informal meeting was held under the Chair- manship of Mr. C. A. Johnson, Programmes Secretary, in an attempt to obtain closer liaison with respect to the dates of meetings of the Sections and Groups and with respect to their subject matter.A similar meeting was again held in January, 1963, and further progress was made in this direction. The Analyst Development Committee, which took the views of a considerable number of people during the course of its investigattons, completed its report to Council in January, 1963. The report, which was considered by Council at a special meeting, contains numerous recommendations relating to the constitutions and functions of editorial and policy committees for The Analyst, the refereeing system, the contents and format of The Apzalyst and the Proceedings, advice to authors and instructions to referees. During the year Dr. Evers retired from the Editorship of Analytical Abstracts. In considering the future of this publication, Council recorded their considerable debt to Dr.Evers for the part he had played in gaining for AnaZyticaZ Abstracts the high esteem in which the publication was now held in the field of analytical chemistry. I t is fully intended that AnaZyticaZ Abstracts will in future be given the support necessary to maintain and to increase its high reputation. He spent a week a t the Feigl Anniversary Symposium, where, at the invitation of the Midlands Section, he took the Chair a t the opening and closing sessions, and he represented the Society at the annual dinners of The year 1962 has been busy for the President, Dr. Amos.May, 19631 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 335 other Societies and at the Ramsay Dinner, at which he replied to the toast to the guests.In addition he took an active part in the organisation of the 1st International Congress of Food Science and Technology, serving as a member of the Executive Committee and as Chairman of the Publicity Committee. The Council records with particular pleasure the award of the C.B. to the Honorary Treasurer of the Society, Dr. D. T. Lewis. Council also records with pleasure the award of the C.B.E. to Professor ,4. C. Frazer and Professor H. 13. Nisbet, and the award of the O.B.E. to n r . A. 81. Smith. The Society now has 2097 members, an increase of 44 over the membership of a year ago. LONG MEMBERSHIP-The congratulations and good wishes of the Council are extended to Dr. L. E. Campbell, Major F. K. Donovan, Dr. E. B. Hughes, Dr. D. W. Kent-Jones, Mr. A.W. Starey and Mr. R. W. Sutton, O.B.E., who have completed 40 years of membership. DEATHS-The Council regrets to have t o record the deaths of the following members- A. Alcock F. R. Dodd F. C. B. Marshall J. J. V. Backes H. W. Christian H. V. Horton E. Russell M. Corner R. E. Jones H. B. Salt C. W. Cornwall J. King C. L. Hinton W. J. S. Pringle SOCIETY mamxGs-Six meetings of the Society were held during the year; the papers read and disciissed were- April, 1962, in London: “Square-wave Polarography with Special Reference to the ,4nalysis of Zirconium and Hafnium,” “The Determination of Gold by Extractive Titration,” by A. W. Titley, B.Sc., A.K.I.C. “An -4utomatic Coulometric-titration Assembly,” by P. G. W. Scott, B.Sc., A.R.I.C., and T. A. by D. F. Wood, B.Sc., A.R.I.C., and I<.T. Clark. Strivens, B.Sc. May, 1962, in London, on the Determination of Sterols : “Determination of Cholesterol for Clinical Purposes,” by G. S. Boyd, Ph.L)., A.H.-W.C., A.K.I.C. “Determination of Cholesterol and its 7-Dehydro Derivatives,” by J . Glover, M.Sc., Ph.D., A.R.I.C. “Determination of Vitamin-D Secosterols,” by E. Kodicek, M.D., Ph.D. “Gas Chromatographic Examination of Sterols,” by C. J. W. Brooks, Ph.D., A.R.C.S. “The Determination of Animal Fat in Vegetable Fats by Gas Chromatographic Analysis,” by K. R. “The Determination of Plant Sterols,” by Professor T. W. Goodwin, D.Sc., F.R.I.C. “Determination of Sterols of Wool Wax and Related Materials,” by E. V. Truter, Ph.D., A.R.C.S., Beerthuis, Dr. Chem. D.I.C. October, 1962, in London, on Recent Developments in Polarography : “Pulse Polarography,” by H.M. Davis, B.Sc., A.Inst.P., A.R.I.C. “Differential Cathode-ray Polarography,” by H. I. Shalgosky, B.Sc., A.R.I.C. “Analytical Aspects of Radio-frequency Polarography,” by Dr. H. W. Nurnberg. November, 1962, in London, on Fluoride, Teeth and the Analyst: “The Determination of Fluorine in Inorganic Materials by Pyrohydrolysis,” by H. J. Cluley, M.Sc., Ph.D., F.R.I.C. “Fluoridation of Public Water Supplies,” by J. Longwell, D.Sc., F.R.I.C., F.R.S.H. “The R81e of Analysis in Investigating the Mode of Action of Fluoride in Tooth Decay,” by G. N. Jenkins, M.Sc., Ph.D. December, 1962, in London, on Applications of X-ray Fluorescence : “The Applications of X-ray Fluorescence Spectrometry in the Steel Industry,” by D.F. Sermin, “The Determination of Lead in Air Filters, Vanadium - Nickel Ratios in Oil Ashes, and Strontium “X-ray Fluorescence in Archaeology a t the Museum Laboratory,” by E. T. Hall, M.A., D.Phi1. A.Met. in Tap Water by the X-ray Fluorescence Spectrometer,” by R. G. Stone, B.Sc., A.R.I.C. February, 1963, in London, on Particle-size Analysis: Some Methods Used in the Sub-sieve Range : “The Size Analysis of Insoluble Drugs,” by M. J . Thornton, B.Sc., A.R.I.C. “Particle-size Analysis in the Formulation of Pesticides,” by C. G. L. Furmidge, B.Sc., Ph.D., “Particle Sizing in Aerosol Systems,” by D. A. Blyth, B.Sc., J . M. Creasey and N. W. Wootten. A. R. I .C. B.Sc., A.1nst.P.336 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 [AIzUbySt, VOl. 88 SECTIONS AND GROUPS The present membership of the Sections and Groups, as will be seen from the reports that follow, is- North of England Section . ... .. . . 431 Scottish Section . . * . .. .. .. 117 Western Section . . , . .. .. .. 123 Midlands Section . . . . . . .. . . 372 Microchemistry Group . . . . . . . . 805 Physical Methods Group . . .. .. .. 904 91 Biological Methods Group . . .. . . .. 331 Because the main concentration is centred round Merseyside and Manchester, Liverpool and Manchester have again been the main centres for meetings. We record with sorrow the death of Mr. A. Alcock, Honorary Secretary during 1955. In June, 1962, after a very successful period of office, Mr. Brian Hulme relinquished his post as Honorary Secretary and Treasurer, a. post he had held since June, 1958.Mr. G. F. Longman was elected by the Committee to act as Honorary Secretary until the next Annual General Meeting. The papers presented and discussed were- Liverpool, January, 1962, Annual General Meeting : Atomic Absorption Spectroscopy Discussion Panel NORTH OF ENGLAND sEcTIoN-Membership of the Section totals 431. “The Work of the Laboratory of the Government Chemist,” by D. T. Lewis, Ph.D., D.Sc., M.R.S.H., F.R.I.C. Manchester, April, 1962, jointly with the Biological Methods Group : Llandudno, May, 1962, Summer Meeting : Belfast, June, 1962, jointly with the Scottish Section: Discussion on “The Assessment of Psychostimulants,” introduced by M. W. Parkes, BSc., Ph.D. “Some Experiences in Forensic Science,” by G. B. Manning, B.Sc., M.B., Ch.B., F.R.I.C.“Investigations on the Determination of Noble Metals by Oscillographic Polarography, I ’ by I. Beattie and R. J. Magee, M.Sc., Ph.D., F.R.I.C., F.I.C.I. “Analytical Applications of the Flame Emi:ssion Spectra of Lead and Titanium,” by C. L. Chakra- barti, M.Sc., A.R.I.C., R. J. Magee, M.Sc., Ph.D., F.R.I.C., F.I.C.I., and Professor C. L. Wilson, Ph.D., DSc., F.R.I.C., F.I.C.I. “An Ultramicrospectrophotometric Method for t e Determination of Complex Cyanides,” by F. Haba and Professor C. L. Wilson, Ph.D., D.$c., F.R.I.C., F.I.C.I. “Differential Cathode-ray Polorography,” by H. M. Davis, B.Sc., A.Inst.P., A.R.I.C. “Instrumental Methods of Continuous Analysis,” by G. Jessop, M.Sc., Ph.D. “Applications of Vapour-phase Infra-red Spectroscopy to the Functional Group Analysis of Propoxy “Applications of Modern Techniques in Spectroscopy,” by R.A. C. Isbell, A.1nst.P. “The Activation Analysis of High-purity Beryllium Using Penetrating Radiations,” by C. A. Baker. “Some Analytical Applications of Mass Spectrometry,” by A. Quayle, M.Sc., A.R.I.C. “A Modular Gas Chromatograph System for the Analysis of Exit Streams from Reactors and for the Application Work Required for Process Analysers,” by C. W. Munday, B.Sc., A.R.I.C., and G. R. Primavesi, B.A. “The Methylene Insertion Reaction for the Identification of Hydrocarbons by Gas Chromatography,” by E. S. Lane, B.Sc., Ph.D., F.R.I.C. Discussion on “Quantitative Gas - Liquid Chromatography in the Routine and Research Labora- tories,” introduced by A. F. Williams, B.Sc., F.R.I.C. and Butoxy Compounds by Modified Zeisel Reactions,” by D.M. W. Anderson, B.Sc., Ph.D. Lathom, October, 1962 : “The Analytical Laboratory in the Glass Industry,” by F. Hartley, F.S.G.T., F.R.I.C. Middlesbrough, November, 1962, jointly with the Tees-side Section of the Royal Institute of “Solvent Extraction of Inorganic Compounds, Some Recent Developments,” by Professor H. M. N. Chemistry : H. Irving, M.A., D.Phil., D.Sc., F.R.I.C., L.R.A.M. Manchester, December, 1962, jointly with the Physical Methods Group : “Nuclear Magnetic Resonance,” by Professor E. R. Andrew, M.A., Ph.C.May, 19631 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 337 SCOTTISH sEc-rroN-Membership of the Section stands at 117 against last year’s total of 123. During 1962, seven meetings have been held, five in Glasgow, one each in Edinburgh and Belfast.The Belfast meeting, a two-day Symposium, was shared with the North of England Section. Two other meetings were held jointly with local Sections of other Societies: the November meeting with the Society of Chemical Industry, and the December meeting, as usual, conjointly by all four Chartered Bodies. Audience numbers are greater, it seems, when the subject is of a more general nature rather than from a specific part of chemistry. The Annual General Meeting was not well attended, and it has been decided that no lecture will be given in future after the luncheon and business meeting. The Section Committee records with pleasure the presence of the President of the Society at the Ramsay Dinner, when he ably replied to “The Guests.” The papers presented and discussed were- Glasgow, January, 1962, Annual General Meeting : “Applications of Analysis to Research Problems in the Gas Industry,” by G.R. Boreham, BSc., A.R.I.C. Edinburgh, February, 1962 : “Death by Poisoning,” by A. C. Hunt, M.D. “Problems in Criminal Investigation,” by Det. Supt. J. I<. McLellan, M.A., BSc., A.R.I.C. “The History of Food Technology,” by T. McLachlan, D.C.M., A.C.G.F.C., F.R.I.C., M.I.Bio1. Details of the papers read a t this meeting are given in the report on the North of England Section. “The Chemistry of Wines and Spirits,” by E. C. Barton-Wright, D.Sc., F.R.I.C., M.I.Bio1. Glasgow, March, 1962 : Belfast, June, 1962, jointly with the North of England Section: Glasgow, October, 1962: Glasgow, November, 1962, jointly with the Glasgow Section of the Society of Chemical Industry on Cellulose Ethers : “Applications of Cellulose Ethers,” by F.C. Hall, Ph.D., M.Sc., A.M.I.Chem.E., F.R.I.C. “Analysis of Cellulose Ethers,” by A. F. Williams, B.Sc., F.R.I.C. Glasgow, December, 1962, jointly with the Chemical Society, the Society of Chemical Industry and the Royal Institute of Chemistry: WESTERN SECTION-The membership of the Section now stands at 123. During 1962 there have been 6 meetings of the Section, including the Annual General The meetings have all been joint meetings, either with the local sections of the Royal “Thoughts on Meat,” by E. C. Bate-Smith, M.Sc., Ph.D., M.1nst.R. Meeting. Institute of Chemistry or with a Group of the Society.January, 1962, Newport, Annual General Meeting, followed by joint meeting with the Cardiff The papers presented and discussed were- and District Section of the Royal Institute of Chemistry : “Radioactivity Measurements in Monmouthshire,” by G. V. James, M.B.E., M.Sc., Ph.D., F.R.I.C. March, 1962, Swansea, jointly with the Physical Methods Group and the South Wales Section of the Royal Institute of Chemistry : “Spectrofluorimetry,” by C . A. Parker, B.Sc., Ph.D., F.R.I.C. “X-ray Fluorescence Analysis,” by R. J. Otter, B.Sc., Ph.D. April, 1962, Newton Abbott, jointly with the South Western Counties Section of the Royal Institute of Chemistry : “The Technique of Sampling,” film introduced by W. T. Elwell, F.R.I.C. “Sampling of Ore,” by G. V. James, M.B.E., M.Sc., Ph.D., F.R.I.C.“Sampling of Soils and Crops,” by B. M. Dougall, M.Sc., F.G.S., A.R.I.C. “Sampling of Fertilisers, Foods and Feeding Stuffs,” by F. W. Marston. “Sampling of Liquids,” by G. J . C. Nash, F.R.I.C. “Sampling for Atmospheric Pollution,” by B. T. Commins, M.Sc., A.R.I.C. “Sampling of Airborne Dust,” by N. M. Potter, M.Sc., Ph.D., F.Inst.F., M.1 .Min.Ed., F.R.I.C.338 [Analyst, Vol. 88 October, 1962, Salisbury, jointly with the Mid-Southern Counties Section of the Royal ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 Institute of Chemistry : “The Rble of the Analyst in the Food Industry,” by Miss M. Olliver, >I.%., F.1C.I.C. November, 1962, Gloucester, jointly with the Rristol and District Section of the Royal Institute of Chemistry: Social evening.December, 1962, Cardiff, jointly with the Cardiff and District Section of the Royal Institute of Chemistry : MIDLANDS SEcTIoN-The membership of the Section is 372, consisting of 353 Ordinary Members and 19 Junior Members. This is a total increase of 17 members during the year. There are 9 Honorary Members of the Section. Twelve meetings were held during the year : 5 in Birmingham, 2 each in Xottingham and Luton, and 1 each in Coventry, Wolverhampton and Northampton. The Feigl Anniversary Symposium, honouring Professor Fritz Feigl’s 70th birthday, was held at Birmingham University during April, 1962. Professor Feigl, an Honorary Mem- ber both of the Midlands Section and of the Society, himself chose Birmingham for this function. Presentations were made to Professor Feigl by delegations from Russia and Japan, and by the Chairman of the Microchemistry Group on behalf of all Microchemists.Elwell Award, 1962-This annual award was won by Mr. F. J. Wallace, of Foseco Inter- national Ltd., for- his paper on “The Determination of Magnesium in Aluminium Alloys by Atomic Absorption Spectroscopy.” January, 1962, Birmingham, on Developments in Gas Chromatography as Applied to “Gem Stoncs and Jewels, Natural and Synthetic,” by R. C. Chirnsidc, F.R.I.C. The Symposium was most successful. The papers presented and discussed were- Polymers : “Recent Advances in Technique,” by D. H. Ilesty. “Gas Chromatography and its Use in Polymer Chemistry,” by C. A. Finch. “The Separation of the Degradation Products of I’olymers,” by R. S .Lehrle. February, 1962, Birmingham, jointly with the Midland Region of the Association of Clinical “Automatic Equipment for the Analytical Laboratory,” by G. V. R. Mattock, B.Sc., Ph.D., A.R.I.C. “Automatic Methods in the Analytical Laboratory,” by I. D. P. Wotton, M.A., M.B., Ph.D., F.R.I.C. Biochemists : February, 1962, Luton : March, 1962, Birmingham : Annual General Meeting March, 1962, Nottingham: “Application of Radio-isotopes in Analysis,” by D. Gibbons, B.Sc., Ph.l)., A.R.I.C. April, 1962, Wolverhampton : “The Determination of Boron,” by R. H. Biddulph, M.A., B.Sc., Ph.D., and H. J . Cluley, M.Sc., May, 1962, Northampton, jointly with the Physical Methods Group and the Birmingham and Midlands Section of the Royal Institute of Chemistry, on Recent Developments in Semi-conductor Analysis : “The Spectrographic Determination of Some Impurities in Gallium Arsenidc,” by J.H. Oldfield, “Radioactivation Analysis of Semi-conductors,” by D. Hazelby, A.R.I.C. “The Determination of Carbon and Silicon in Gallium Arsenide,” by A. C. Tyrrell, J. M. Page and May, 1962, Luton, jointly with the Microcliemistry Group on The Status of Trace Metal “Analytical Research,” by J . Haslam, D.Sc., F.lt.1 .C. Ph.D., F.R.I.C. F.R.I.C., and D. L. Mack. D. C. Newton, BSc. Determinations : “Ferrous Metals,” by B. Bagshawe, F.I.M., 1M.Inst.F. “Non-Ferrous Metals,” by W. T. Elwell, F.K.I.C. “Distribution in Soils,” by H. H. le Riche, I’h.D.May, 19631 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 339 October, 1962, Birmingham : presentation of papers for the Elwell Award, 1962.“ A Method for the Determination and Characterisation of Organic Bases in Pharmaceutical “The Determination of Fluoride by Complexometric Titration,” by M.,4. Leonard, B.Sc., Ph.D., “The Determination of Magnesium in Aluminium Alloys by Atomic Absorption Spectroscopy,” Preparations,” by R. E. King, A.R.I.C. A.R.I.C. by F. J. Wallace. October, 1962, Nottingham: November, 1962, Coventry : December, 1962, Birmingham, jointly with the Microchemistry Group : “The Statistical Approach to Analysis,” by D. A. Pantony, T.D., B.Sc., Ph.D., A.R.C.S., F.R.I.C. “Solvent Extraction,” by T. B. Pierce, B.Sc., M.A., D.Phil. “The Determination of Carbon and Hydrogen in Organic Materials,” by Miss A. M. G. Macdonald, MICROCHEMISTRY GRouP-The membership of the Group is now 805, an increase of 48 in the past year.At the Feigl Anniversary Symposium in Birmingham in April, 1962, the Chairman of the Group, Mr. C. Whalley, presented Professor Feigl with a glass vase on behalf of all micro- chemist s. During 1962 four Ordinary Meetings of the Group were held: in London on February 23rd- (the Annual General Meeting followed by an Ordinary Meeting for the reading of origins€ papers); in Luton on May 11th (jointly with the Midlands Section) ; in Dublin from September 21st to 23rd (jointly with the Dublin and District Section of the Royal Institute of Chemistry) ; in Birmingham on December 14th (jointly with the Midlands Sections). The papers read were- London : MSc., Ph.D., A.R.I.C. “The Ultra-micro Determination of Halides a t Extreme Dilution,” by E.Bishop, B.Sc., A.R.C.S.T., “Development of a Simplified Spectroscopic Method for Non-routine Solution Analysis of Trace “The Ultra-micro Quantitative Determination of Ammonia by Means of Indanetrione Hydrate,” A.R.I.C., and R. G. Dhaneshwar, M.Sc. Metals,” by C. P. Cole. by S. Jacobs, MSc., Ph.D., F.R.I.C. Luton: Dublin : Details of the papers read a t this meeting are given in the report on the Midlands Section. “Modern Trends in Small-scale Inorganic Analysis,” by Professor T. S. Wheeler, D.Sc., F.R.I.C., F.I.C.I., R. C. Chirnside, F.R.I.C., R. A. Chalmers, B.Sc., Ph.D., and D. J . Hingerty, M.Sc., Ph.D., F.R.I.C. Birmingham : Details of the paper read a t this meeting are given in the report on the Midlands Section. Five informal discussion meetings were held in London and one in Dublin.The topics discussed and the speakers who introduced them were: “Determination of Traces of Copper,” introduced by E. I. Johnson, M.Sc., F.R.I.C., and D. B. Adams, “Do-it-yourself Ideas in Microchemical Apparatus.” “Ion Exchange in Microchemistry,” introduced by J . Pilot, B.Sc., and J. A. R. Genge, M.Sc. “Differences Between Continental and British Practice in the Determination of Elements in Organic A Review of all Topics Discussed a t these Meetings. “Modern Trends in Analysis.” B.A., B.Sc. Compounds,” by W. Schoniger, Dr.ing. PHYSICAL METHODS GROUP-The number of Group members is now 904. This is an increase of 60 since the last Annual General Meeting. The Group has set up an Atomic Absorption Spectroscopy Discussion Panel, under the Chairmanship of Mr.W. T. Elwell, F.R.I.C., and with Mr. D. Moore as Honorary Secretary, with the aim of arranging discussion meetings on applications of this technique.340 [Afialyst, Vol. 88 During the past year the Group has held five Ordinary Meetings; three were held in London and one each in Swansea and Northampton. The Swansea meeting was held jointly with the Western Section and the South Wales Section of the Royal Institute of Chemistry, the Northampton Meeting jointly with the Midlands Section and the Birmingham and Midlands Section of the Royal Institute of Chemistry, and one London Meeting jointly with the Polarographic Society. The papers read (and discussed at the Ordinary Meetings of the Group were- London, November, 1961 : London, February, 1962 : Swansea, March, 1962 : Recent Developments in the Analysis of Semi-conductors-Northampton, May, 1962 : Recent Work in Radiochemical Methods of Analysis-London, October, 1962 : ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 “Electrochemical Methods in Analysis,” by G.W‘. C. Milner, D.Sc., A.Inst.P., F.R.I.C. “Some Surface Effects in Electro-analytical Chemistry,” by Professor H. A. Laitinen. Details of the papers read at this meeting are given in the report on the Western Section. Details of the papers read a t this meeting are given in the report on the Midlands Section. “The Use of Charged Particles for Activation Analysis,” by T. B. Pierce, B.Sc., M.A., D.Phi1. “Recent Developments in the Use of Radio-isotopes in Analysis,” by T.T. Gorsuch, BSc., Ph.D., “Recent Uses of Labelled Reagents in Biochemical Analysis,” by J. K. Whitehead, M.Sc., Ph.D., BIOLOGICAL METHODS GROUP-During -the year the membership of the Group has In the year ending on October 31st, 1962, the Group has held, in addition to the Annual The papers read A.R.I.C. A.R.C.S., D.I.C., A.R.I.C. increased from 316 to 331. General Meeting, three discussion meetings arid made one laboratory visit. and discussed were- December, 1961, London, Annual General Meeting : Discussion on “The Assessment of Anti-atherosclerotics,” introduced by G. S. Boyd, Ph.D., A.H.-W.C., A.R.I.C. February, 1962, London : Discussion on “The Assessment of Antibiotics in Animal Feeds,” introduced by G. Sykes, M.Sc., F.R.I.C. April, 1962, Manchester : Details of the paper read at this meeting are given in the report on the North of England Section.ANALYTICAL METHODS COMMITTEE-The progress of work during the year has been maintained. The number of committee meetings (73) showed an increase over that for the previous year (64), although the number of active committees and panels had decreased from 22 to 18. The book of Official, Standardised and Recommended Methods of Analysis, compiled and edited by Mr. S. C. Jolly, is due to appear in print early in 1963: this com- prises about 350 pages of recommended methods published in Reports of the Analytical Methods Committee since 1927, together with a comprehensive Bibliography of authoritative methods emanating from countries on both sides of the Atlantic. Also with the printer are recommended methods for determining Trace Elements with Special Reference to Fertilisers and Feeding Stuffs: these are being published as a booklet comprising some 40 pages.A new departure from the usual type of Report by the Analytical Methods Committee is one prepared by the Sub-committee on Particle Size Analysis: this is a classification of methods of measurement of particles in the sub-sieve range (b., below 76 microns), and it is to be published in The Analyst as a Review article. This classification represents the first part of the Sub-Committee’s work; the second part is intended to be an appraisement of the principles or techniques of the methods listed in the classification, and it is envisaged that this work, which will necessarily involve experimental tests, will take some considerable time.Other programmes completed during the year include the preparation of a Report on the Determination of Copper, by the Metallic Irnpurities in Organic Matter Sub-committee (nowMay, 19631 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 341 with the printer); a Report on Nitrogen Factors for Beef, by the Meat Products Sub-Com- mittee; a Report on the Determination of Riboflavin in Animal Feeding Stuffs, by the Vita- mins (Water-soluble) Panel of the Additives in Animal Feeding Stuffs Sub-Committee ; a Report on the Oxygen-flask Method for the Determination of Organically-bound Chlorine in Pesticides and Formulations, prepared by the Chlorine in Organic Compounds Sub-Com- mittee; and a revision of the methods for the Determination of the Capsaicin Content of Capsicum and its Preparations (originally published in The Analyst in 1959).With the completion of most of its programme, the Additives in Animal Feeding Stuffs Sub-committee has been disbanded : one of its original Panels-on Prophylactics-has now been reorganised as a Sub-committee in its own right in order to carry on the very lengthy programme originally assigned to it. No new committees or panels have been set up during the year. made were- LIAISON WITH OTHER SCIENTIFIC oRGANISATIONS-During the year the appointments Chemical Council : Dr. D. T. Lewis. Joint Library Committee, Chemical Society : Dr. J. G. A. Griffiths. Parliamentary and Scientific Committee : Dr. J. H. Hamence. Royal Institute of Chemistry, Summer School Organising Committee : Mr.A. N. Leather and Mr. C. Whalley. International Congress XIX of Pure and Applied Chemistry, 1963, Scientific Committee : Nr. C. Whalley. B.S.I. Committees: Mr. S. A. Price: Chemical Divisional Council. Dr. C. B. Barrett : Technical Committee on Analysis of Emulsifying Agents etc. Dr. R. E. Stuckey: Technical Committee on Sampling of Chemical Products. Dr. R. E. Stuckey: Technical Committee on Bulk Measurement of Chemical Products. Dr. R. E. Stuckey: Technical Committee on Physical Tests in Chemical Products. Mr. G. A. Vaughan : Technical Committee on Terminology and Rules for the Expression Mr. G. A. Vaughan: Technical Committee on Preferred Ranges of Indicator Solutions. The Council of the Society thanks all its representatives for the work they have done in of Reagent Strengths.the various Committees and at various meetings during the year. HONORARY TREASURER’S RmoRT-The Society’s auditors, Messrs. Ridley, Heslop and Sainer, carried out the audit of the Society’s accounts, investments, etc., and have provided a balance sheet for the year ended October 31st, 1962. This was submitted to the Finance Committee on Wednesday, December 12th, and approved for submission to Council at their next meeting on Wednesday, January 9th, 1963. Copies of the accounts and balance sheet have been circulated to all members. The Society continues to possess a strong and vigorous membership, which is still slowly increasing. It will be remembered that our printers, Messrs. W. Heffer & Sons Ltd., Cambridge, increased their printing charges in 1961 by 10 per cent.for both The AnaZyst and Analytical Abstracts. This factor and the reasonable increase in salaries made by the Finance Committee to the permanent staff of the Society have increased expenditure and consequently diminished the excess of income over expenditure. The allocations to the Society’s reserves for premises, special publications, etc., were therefore decreased from El000 to L500. These reserves will be quite heavily depleted in the year 1962-63, by necessary compilation expenses associated with342 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 [Analyst, VOl. 88 the Annual Index for 1963 and 1963 and also with the Decennial Index covering the first ten years of Analytical Abstracts. The compilation costs of these alone will amount to about E1200, exclusive of printing, publication, etc. No new investments have been made by the Society during the past year, the bulk of the monies having been allowed to accumulate in the Deposit Account at normal rates of interest.Full details of the Schedule of Investments are given in the balance sheet, the fall in the market value of the Society’s holdings being indicative of the financial fluctuations in share values that have affected both this country and the U.S.A. during the past year. In financial transactions of this nature, the Society is continually advised by its brokers, Messrs. Chance & Co., and there does not appear to be any reason for any particular change in our investment policy. The position of the Society’s finances may thus be regarded as satisfactory, although static, but it must be remembered that the Society is not run for profit but for extending those fields of knowledge embracing the science of analytical chemistry.Nevertheless, it is essential that the financial virility of the Society be preserved by the recruitment of new members and by increasing those revenues obtained by the sales, not only of The Analyst and Analytical Abstracts, but also of those authoritative publications that it is right and proper that the Society should publish. PROGRAMMES COMMITTEE-Attendance at meetings during the year has been about average, although one evening, that on which Applications of X-ray Fluorimetry were pre- sented, was seriously marred by fog.The element of chance that attends the traditional meetings devoted to the presentation of original contributions has led to a recent decision to abandon this type of meeting and to replace it, for a trial period, by some meetings arranged for the presentation of researches by work:ers in Universities and Colleges of Advanced Technology. Much time has been devoted during the past year to a consideration of a pro- posal that the Society should hold a Conference on Analytical Chemistry; the proposal has been accepted and it seems probable at the moment that such a Conference will be held at Nottingham University during the third or fourth week in July, 1965. It is intended that this Conference should be devoted, in the main, to original work rather than to review papers.The scientific content of the meeting will be organised by the Programmes Committee and a local Committee will be formed to deal with its organisation. THE ANALYST-The introduction with current volume of a white, calendered, paper in place of the former cream matt paper is probably the most noticeable of recent changes made to improve the general appearance of The AnaZyst. Another is the transformation of the old “Notes” section into a section of Short Papers. The 1962 volume contained 984 pages, 56 more than the record 1960 volume, and 124 more than last year. This increase was required by a slightly greater number (9 more) of papers and notes describing original work, the total being 160, in addition to five Review Papers and four Scientific Reports prepared by various Committees.There has been a sharp increase in the number of Book Reviews (83 as against 59 last year). Circulation has again increased, and 7300 are now being printed of each issue (7000 last year). Four of the five Review Papers were concentrated in the first half of the year; it has not proved possible to maintain an even flow, and it must be expected that there will be rather greater numbers in some years than in others. Their value to members and non-members alike is emphasised by the continued steady sale of reprints. Eleven issues of the Bulletin were distributed with The Analyst during the year, During the year Miss E. R. Prince joined the editorial staff in place of Mr. Harris, who has transferred to Analytical Abstracts as Assistant Editor.ANALYTICAL ABSTRACTS-seVeral changes of staff took place in 1962, the most important being the retirement, on October 31st, of Dr. N. Evers from the Editorship, which he had held since the inception of Analytical Abstracts in 1954. He was succeeded by Mrs. H. I. Fisk, with Mr. Brian Harris, formerly Editorial Assistant in The Analyst office, as Assistant Editor. Dr. R. E. Essery, who had been working as a part-time assistant since 1959, retired in June. In spite of these, and other changes, the total number of abstracts published in 1962 was 5564 on 716 pages; this is the highest in any one year since Analytical Abstracts began, the previous record being 5522 abstracts in 1960.May, 19631 ANNUAL REPORT OF THE COUNCIL: MARCH, 1963 343 Sales have continued to rise and, as a result of a study by a large industrial group in the U.S.A. on a replacement of their own bulletin with Analytical Abstracts, we have now received an order from them for 150 subscriptions in 1963. In view of this order it was decided that we should try to extend our advertising in the U.S.A., on an exchange basis. Of the several journals approached, favourable replies were received from Applied Spectroscopy, Journal of the Association of Ojicial Agricultural Chemists and Cereal Science Today. Although it is against the policy of the Journal of Biological Chemistry to enter into exchange agreements, they have offered to insert an occasional advertisement, free of charge, when convenient to them. The equivalent advertisements from America will appear in The Analyst, this being a more suitable medium than Analytical A bstracts. The Decennial Index will be due in 1964, and it has been arranged that Dr. N. Evers will prepare the matter for the Subject section. Certain changes were made in the constitution of the Editorial Committee. Mr. B. A. Ellis retired from the Chairmanship in July, but agreed to remain on the Committee as an ordinary member, and was succeeded by Mr. B, S. Cooper; Mr. A. G. Jones, Imperial Chemical Industries Ltd., Plastics Division, was co-opted in October as an additional member to deal with the organic chemistry field; and Dr. N. Evers, on his retirement from the Editorship of Analytical Abstracts, has agreed to remain on the Committee as an ordinary member. About 40 regular abstractors attended, and many problems, both editorial and abstracting, were discussed. An abstractors’ meeting, followed by a lunch, was held in March. A. J. AMOS, President. R. E. STUCKEY, Honorary Secretary.

ISSN:0003-2654    

DOI:10.1039/AN9638800334

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

344 ADDRESS OF THE RlETIRING PRESIDENT [Analyst, Vol. 88 Address of the Retiring President A. J, AMOS, O.B.E., B.Sc., Ph.D., F.R.I.C. (Delivered after the Annual General Meeting, March 8th, 1963) The Society Yesterday, To-day and To-morrow WE have reached a stage in the life of our Society when more than ever before in its history we should be forward-looking. The potentialities for extension of the scope of its interests, for expansion of its membership and for enhancement of its status are great, but, if they are to be brought to fruition, our outlook must be more a welcome for the future than a pride in the past. We must give as much thought and supervision to a long-term policy as we do to the planning of our yearly programmes. Before this can be done, we must have clear in mind the direction and the scope of the progress we wish to achieve; we must be agreed upon our goal before we can plan ahead.In this address I shall leave with you my thoughts upon how and to what end we should direct our efforts in the hope that they may prove to be a stimulus that will lead to the preparation and implementation of a planned policy for the future. But although my main concern is to look ahead, I am mindful of the precept of Lord Halifax that- “The best way to suppost: what may come is to remember what is past.” The birth certificate of our Society is to be found in the Chemical News for August 14th, 1874, where it is reported that 27 analysts, who were dissatisfied with the Report of a Par- liamentary Committee on the Adulteration Act of 1872, met together at a Cannon Street hotel and agreed that “an Association of Public Analysts be formed for the purpose of mutual assistance and co-operation.” The name selected for the Association was “The Society of Public Analysts.” The reason that prompted the formation of this Association, its inaugural constitution and its adopted title justify the conclusion that the initial interest of our Society was not analytical chemistry, but the analysis of food and drugs. That this was so is clear from the objects of the Society, which were published a few months later.These were- (i) To promote and maintain the efficiency of the laws relating to adulteration. (ii) To promote, and as far as possible to secure, the appointment of competent Public Analysts. (iii) To improve the processes for the detection and quantitative estimation of adultera- tion and to secure uniformity in the statement of the results by holding periodical meetings for the reading and discussion of original papers on chemical and micro- chemical analysis, especially with reference to the detection of adulteration. When a quarter of a century had passed, the Rules of the Society were amended so that membership was not restricted to “analysts in practice,” but was open to anyone who had a genuine interest in analytical chemistry.Eight years later, when the Society was incorporated, opportunity was taken to extend its title and to broaden its objects in recog- nition of the “other analytical chemists” who were then within its ranks. Nevertheless, another 5 years passed and the Society was 38 years old before precedent was broken and the Presidential Chair was occupied by a representative of the “other analytical chemists. ” Reference to the volumes of The Analyst published in that and the other years of the fourth decade of the Society’s existence provides supporting evidence that the interests of the Society were becoming less sharply focused on food and drugs and were coming more into line with its revised objects, which were “to encourage, assist and extend the knowledge and study of analytical chemistry and of all questions relating to the analysis, nature and composition of natural and manufactured materials.” Critical surveys of advances in methods of analysing cellulose and rubber were commissioned for The Analyst and the subjects of original papers in the journal included dyestuffs, paper, turpentine, mineral oils, rubber, disinfectants, metallic ores and alloys, detergents, coal, gases, blood stains and documents.May, 19631 ADDRESS OF THE RETIRING PRESIDENT 345 Diversification of its interests material-wise continued to increase as the Society veered numerically towards a Society of Other Analytical Chemists and Public Analysts.At the same time, because of the progressive discovery of new analytical tools, a cross segregation of members based on methodology tended to develop. Eventually this trend reached a stage that warranted official recognition and support, and these were provided in 1943 by the decision of Council to permit the formation within the Society of Groups for the furtherance of specialised branches of chemical analysis.In less than 2 years, three Groups were in existence-a Microchemistry Group, a Physical Methods Group and a Biological Methods Group. At the time the formation of the first Group was imminent, which fell in the 70th year of the Society’s existence, the number of papers dealing with food and drugs appearing in any volume of The Analyst was little more than one-third of the total. The preponderance of papers on analysis in other contexts tended to become even greater as papers read at meetings of the three active Methods Groups began to flow into the journal, because very few of them dealt with food and drugs. This pronounced shift of emphasis in the themes of the papers in the Society’s journal was paralleled by a change in the structure of its membership; by the time the Society was 75 years old its “other analytical chemists” out- numbered its Public Analysts by more than 15 to 1.From a small group of Public Analysts absorbed in the problems of food and drug analysis the Society had grown into a large band of chemists whose collective interests covered the fundamental principles of analytical chemistry, methodology, the application of analytical techniques in a wide range of contexts other than food and drugs, and the teaching of analytical chemistry. The name of the Society, which in any event was too long and cumbersome, was no longer apposite, and, indeed, was misleading. Some progressively minded members of Council who subscribed to Bernard Shaw’s dictum that “all progress is initiated by challenging current conceptions and executed by supplanting existing institutions” began to press for a change of title, but they met considerable opposition; they found it easy enough to “challenge current conceptions” but a very uphill task to “supplant existing institutions.” However, eventually good sense prevailed and at the close of 1953 the Society became “The Society for Analytical Chemistry” and entered the fold of learned societies.Some Public Analysts took the view that with this change they were losing their birth- right, whereas their emotion should have been pride in the fact that the vision and the efforts of their enthusiastic forbears who founded an Association in 1874 and nurtured it in its early years had culminated in a learned Society of nearly 2,000 members that catered for all aspects of theoretical and applied analysis.I am sure that those early Public Analysts to whom we owe so much-men like Redwood, Muter, Allen, Hehner and Dyer, to mention but a few-would have been proud indeed had they had a foresight of the outcome of their labours. With this change of name, the Society of yesterday became the Society of to-day. We are now in the last year of our first decade as a learned Society and it is an opportune time to review our achievements and our policies-to decide whether our resources, our plans and our activities have been so directed that we are serving analytical chemistry in general and our members in particular to the best of our capabilities.It is much to the credit of the Society that when British Chemical Abstracts were dis- continued, an event that occurred about the time the Society changed its name, Council decided to repair the loss to analytical chemists by publishing monthly a journal of abstracts of analytical papers. This was particularly a laudable action because it called for additional and specialised staff and it was undertaken at a time when the Society was experiencing an annual loss on its journal. Council’s faith in this venture to serve analytical chemistry was vindicated, and to-day the sales figure for Analytical Abstracts is over 7500. The international reputation of these abstracts, which are the only ones relating to analytical chemistry that can be purchased independently of abstracts of other branches of science, is deservedly high, but I believe that neither in status nor sales has this publication yet reached its zenith.At the time the Society of yesterday became the Society of to-day it was making an annual loss of about #OOO on The Analyst, and within 3 years the deficit in the annual accounts of Anal_vticaZ Abstracts was a similar sum. These losses were made good-as were the publication losses of other scientific societies-by grants from the Chemical Council, but the situation was a frustrating one. Before the Society could hope to progress, it had to become self-supporting,346 ADDRESS OF THE RE,TIRING PRESIDENT [Analyst, Vol. 88 and it achieved this target in 1958, being the first of the four beneficiary Societies to dispense with the aid of the Chemical Council.It has consolidated its financial position in the intervening years, and, although it has been and will again be faced with unavoidable rises in expenditure, I am confident that we shall never again go back on the dole. Another innovation made since the Society changed its names is the Programmes Committee. Before its appointment, the paper-reading meetings were planned by the Publication Committee and with few exceptions they consisted of papers selected from those submitted for publication in The Analyst. This practice served well enough yesterday, but in the face of the quickening tempo of scientific research its retention would have made the Society a historian instead of a pioneer of analytical developments. The planning of the Programmes Committee has been based upon the sound premise that in selecting topics for meetings of the Society priority should be given to those subjects that are currently of widespread interest.In place of the old type of meeting in which several already submitted papers on widely divorced subjects were read-a type of meeting well suited to the earlier days of the Society of Public Analysts-it favours the meeting at which invited specialists present papers on a common theme, particularly the principles and practice of a modern analytical technique. Reference to the 1962-63 programme of the Society reveals that four of the six paper-reading meetings are of this type, the subjects, for each of which a series of papers was commissioned, being polarography, X-ray fluorescence, particle size analysis and magnetic resonance. The 1961-62 programme had a similar pattern, three of the five meetings having as their respective themes, the oxygen flask combustion technique, new analytical reagents and the application of infrared spectroscopy to analytical problems.In giving the programmes of the Society this new look, the Committee did not at first eliminate the older type of meeting, but in the light of later experience it has decided not to retain it as a regular feature. The meeting arranged for April resembles the old type of meeting in that the programme embraces a number of topics, but there the similarity ends; the papers have not been chosen from those submitted to The Analyst, but will be contributions from research students in universities and colleges of advanced technology.This is a new venture and if it is successful i t might well be repeated in future years. Even if these meetings for research students attract only the relatively small audiences that tended to become characteristic of our traditional multi-subject meetings, there is a good case for their continuance; they will have a missionary impact by bringing the Society to the notice of potential members, whereas at the old type of meeting we only preached to the converted. Because of the trend of advance in applied analysis, the topic of a one-theme meeting will more often than not be a physical method of analysis. Not infrequently the method warrants periodical discussion over a number of years because its devoted band of followers introduce modifications into the technique, make improvements in an instrument or discover new applications of the analytical procedure. However, there is a limit to the number of meetings the parent Society can hold each session, and it may well be that the only way it can keep pace with the advance of analytical chemistry is to relegate the organisation of more meetings to specialist panels.The creation of a Sub-Group, Panel-call it what you will-to provide a forum for t h e dis- cussion of a new specialised analytical technique may have an insurance value by arresting the formation of what has been called a “splinter group,” since the best way of ensuring that the exponents and adherents of a new technique conduct their discussions and reviews under the aegis of the Society is to give them a niche within our constitution. I am sure that Council took a step in the right direction when last year it approved the precedent of permitting non-members of the Society to join the recently formed Atomic Absorption Spectroscopy Discussion Panel.By thus fostering in a practical manner the interests of specialists outside the Society, we effect a liaison that may in the course of time bring some of them into our ranks. Had we been sufficiently forward-looking in this respect in the past the Society might have become the centre for discussions and reports of activities and progress in a newer technique by specialists whose desire to foregather urged them to form organisations of their own.As long ago as 1884 the Council then in office appointed a Committee to examine the various methods of milk analysis in use and to report upon their respective accuracies. Forty years later, the need for standardisation of analytical methods had extended to other fieldsMay, 19631 ADDRESS OF THE RETIRING PRESIDENT 347 of work and had become sufficiently pressing to prompt the Council to appoint a standing Committee to advise when and in what direction a study of the applicability and reliability of competitive methods was desirable. This was the forerunner of the present Analytical Methods Committee. Within a short time, the standing Committee of 1924 had advised and Council had approved the formation of two working Sub-Committees, one to deal with the analysis of condensed and dried milk and the other with essential oils.Last year, its offspring, the Analytical Methods Committee, was supervising 18 Sub-committees and Panels, each of which was either guiding or conducting research on specific analytical problems. This notable expansion of the work of the original Standing Committee was made possible by an action taken soon after we became the Society of to-day, a progressive action of “supplanting existing institutions.” This was an appeal to industry to provide the funds that would enable the Analytical Methods Committee to maintain a paid Secretariat. Until then, not only the collaborative analytical work but all the necessary ancillary secretarial work had been performed free of charge by members of the Sub-committees and Panels.They were all busy men whose professional duties had first call on their time and accordingly the consideration of the outcome of a practical exercise and the issue of a final report were often seriously delayed because the associated not inconsiderable volume of paper work could not be done quickly. Following industry’s avowed interest in and financial support for the work it was doing, the Analytical Methods Committee widened its activities and published a “Bibliography of Standard, Tentative and Recommended or Recognised Methods of Analysis,” a book of 34 sections that contained well over 6000 references. Encouraged by the sale of 1500 copies of this book, the Committee has produced a second edition on more ambitious lines; it is wider in scope and reproduces in full instead of by reference all the Committee’s recommended methods.This book, which bears the title “Official, Standardised and Recommended Methods of Analysis” was published at the beginning of March. Between these two editions, the Ana- lytical Methods Committee published a book of recommended methods for the analysis of trade effluents, based on an investigation made jointly with the Association of British Chemical Manufacturers, and, in a few weeks, will have on a sale a book on the determination of trace elements. The parent Society also has added to what are termed “other publications” in the Annual Accounts by initiating what will become a series of Monographs. It is planned that these Monographs shall be books for the bench rather than for the reference library.The series began with “Methods for the Analysis of Non-Soapy Detergent Products” and this will shortly be followed by “The Determination of Sterols.” Supplementary publications edited by the parent Society or by its Analytical Methods Committee can and undoubtedly will enhance the status and benefit the finances of the Society, but we must never lose sight of the fact that The Analyst and Analytical Abstracts are its life blood. We cannot afford, therefore, to be complacent about sales of The Analyst and Analytical Abstracts, but must periodically review our publication policy. The wisdom of so doing is proved by the fact that in its recent report the specially appointed Analyst Development Committee saw fit to make 30 recommendations.In comparing the Society of to-day with the Society of yesterday I have made no reference to number of employees, size of office accommodation, annual income and expenditure, number of pages in The Analyst, and the like because retrospective comparison of these and other material items are not a true measure of progress. Our concern should be whether we are doing more than we did to stimulate and to sustain the march of analytical chemistry, whether the contributions we may make to this end take heed of the ever-widening horizons of this branch of science, and whether we give adequate coverage to each of the multitudinous interests of those concerned with the teaching, the theory and the practice of analysis. And particularly we should ask ourselves whether we cater too much for the expert and the experienced and serve too little the embryo and newly fledged analysts, because there is truth in Franklin Roosevelt’s observation that the test of progress “is not whether we add more to the abundance of those who have too much; it is whether we provide enough for those who have too little.” Looking back as we have done at the Society of yesterday enables us to gauge the sound- ness and the success of the plans adopted as measures of development.That we have made progress is beyond doubt: now the scope of the Society’s interests extends, as it should do,348 ADDRESS OF THE RETIRING PRESIDENT [Analyst, Vol. 88 over the whole realm of analytical chemistry viewed from the standpoint of techniques or contexts; the meetings of the parent Society are supplemented by meetings organised by specialist Groups and by new Sections, thereby providing greater opportunity for members to keep pace with new work; the old type of meeting comprising papers on unco-ordinated subjects has been replaced by a single-subject meeting that attracts an audience with a keen interest in all the papers in the programme; the work of the Analytical Methods Committee has been intensified and accelerated and has earned the interest and financial support of industry; the programme of each Society meeting is judiciously planned and planned well in advance by a specially appointed Committee instead of remaining a matter of chance; finances have been put on a sound basis; and the Society has undertaken the task of making available throughout the world abstracts of analytical literature.In the light of these and other developments it cannot be denied that to-day the Society, through its meetings, through its journals, through its “other publications” and through its Analytical Methods Com- mittee, is serving analytical chemistry and analysts to better effect than did the Society of yesterday . What of the Society of to-morrow? Its control will not be in our hands, but the success that attends the efforts of those who will be in charge may be much influenced by the course we pursue -what they reap will spring from what we sow. Our first endeavour must be to ensure that in our meetings and in our journal we give complete coverage in the field of analytical chemistry no matter how greatly or how rapidly the field extends.To achieve this, we must maintain a keen, active and well-balanced Programmes Committee. The primary function of this Committee, which, I believe, may well become the most important of the Society’s Committees, will be to keep constant watch for promising new techniques, for new applications of existing techniques, and for industrial and legal developments that create new problems for the analyst, and then to arrange meetings at which specialists will speak on these subjects. A secondary duty of the Com- mittee might well be to remedy the absence from The Analyst of papers on a subject that is of widespread interest or of growing importance by arranging a Symposium on the subject. The possibility and desirability of arranging joint meetings with other organisations should also be frequently reviewed by the Committee.Such meetings not only assist the Society to extend its sphere of influence, but may engender interest in it and thereby initiate recruitment among those who have never enquired what it has to offer because they do not regard themselves as analysts. There are many in this category and we should not neglect any measure that will attract them to our ranks. A chemist who is occupied in making quantitative determinations of one or more constituents of a parent material is still an analyst, even if the identification and separation are performed by an instrument and his final measurement that completes the assay involves only the taking of a reading 011 this same or an ancillary instrument. He may be termed a physicist or a physical chemist, but he is just as much an analyst as his predecessor who made the same determinations by classical analytical procedures, and we should take positive steps to bring to his notice the fact that there is a place for him in our Society.There is need also to forge a link between the Society, perhaps through specialised groups, and organised bodies of those who are interested in the construction and performance rather than the application of specialised analytical tools. Such liaison benefits both bodies; it enables the analyst to understand better the performance, the sources of error, the specificity and the sensitivity of the instrument and it suggests to the instrument specialist possible new analytical uses of the tool.During the investigation made by the Analyst Development Committee, it became clear that despite our graduation from a professional body to a learned Society, The AnaZyst had not acquired the status of a learned journal throughout the academic world. It is under- standable that in days gone by the channel of publication sought for a paper on some funda- mental principle of analysis was one of the recognised learned journals rather than one devoted mainly to papers on food and drugs with special reference to adulteration. The justifiable hope that this attitude would be abandoned in the light of the change in the status of the Society and in the contents of its journal was not realised. No longer do papers on food and drugs predominate in The Analyst, but academic .research workers are still loth t o see their papers surrounded by papers on “applied” analysis.This is not the time nor Having looked from to-day into the past, it is time to turn to the future.May, 19631 ADDRESS OF THE RETIRING PRESIDENT 349 place to delineate upon the line of demarcation between or the relative importances of applied analysis and what has been variously qualified as fundamental, pure or basic analysis, but the issue is clear. Our policy for the future must be to eradicate misconception about the Society and its interests and to preach the interdependence of pure and applied analysis until The Analyst is accepted in academic circles as an appropriate journal for the analytical papers that at present they send elsewhere.In the first place, we may have to go out and seek such papers, relying upon personal appeal and persuasion by members of Council and of the Publication Committee. If these efforts are successful, other papers will follow and the inflow will become self-expanding. But we can do more than this. We can plan to bring the Society more frequently and more closely to the notice of academic institutions. Notices of meetings on notice boards can help, but a closer contact is required; we need to bring the Society itself and not merely records and announcements of its activities into the universities and technical colleges. We are making a start in this direction in the meeting that is arranged for April at the Chelsea College of Science and Technology, but we should plan others that are not designed specifically for post-graduate students.April’s meeting brings the Society to the notice particularly of young analysts still in training-potentially Society members of to-morrow. It is better that they should have first-hand knowledge of the Society before and not after they go into industry or teaching, and we should strive to make this type of meeting a regular feature of our annual programme. We should look upon these meetings as “bread upon the waters” and accordingly not be disheartened if at first they do not attract large audiences. If we achieve what should be our aim-to have the Society of to-morrow recognised as all-embracing in its interests in the field it serves-then its meetings and its journals will be considered to be appropriate for contributions upon not only basic analytical procedures, the application of analysis in specific contexts and the potentialities of specialised analytical tools, but also upon the theory, history, philosophy and teaching of analytical chemistry.As this aim approaches realisation, a venture worthy of consideration would be the publication of two journals rather than a considerably enlarged Analyst. The Analyst would be devoted to papers on analytical problems and procedures particular to the application of analysis in specific contexts, and a new journal, which might be entitled “The British Journal of Analytical Chemistry” would be the site of theoretical and practical papers on fundamental analytical chemistry and papers on the history, philosophy and teaching of analytical chemistry. In my opinion, this would be a development worthy of mature consideration.I realise that it would involve various administration and financial problems, but I believe that they could be solved without great difficulty. Analytical Abstracts has made and will continue to make the Society more widely known, and now produces an income in excess of the cost of production. These are sound, albeit material, reasons why the publication should have a major call upon the Society’s resources, but there is an ethical reason why we should be prepared to make special efforts to ensure its continuation. Having voluntarily undertaken the task of providing this service for analysts, we are under a moral obligation to do all that is within our power to give it per- manency.And our pride as a learned Society and our desire to stimulate the advancement of analytical chemistry should preclude lack of financial support or inadequate supervision of administration ever causing Analytical Abstracts to fall short of the high standard they have attained . The existing Group structure of the Society had much to commend it when it was intro- duced 20 years ago, but its retention unchanged in the Society of to-morrow might become a sign of old fashioned thinking. To-day, very many analysts who are unconversant with filter sticks and other specialised and elegant equipment dear to the heart of the earlier microchemists are working with samples or determining amounts much smaller than those that were the topics of discussion in the early meetings of the Microchemistry Group.As micro-analysis becomes progressively more commonplace, the retention of a major specialist Group devoted to microchemistry will be difficult to justify. The wisdom of retaining the Biological Methods Group as a major Group is arguable for a different reason. Biological methods are still a specialised branch of analysis, but because it is so very specialised its application is limited and advances of note are few and far between. Accordingly, the stage has been reached when the Group Committee finds itself at a loss each year how to build350 ADDRESS OF THE RETIRING PRESIDENT [Analyst, Vol. 88 a programme. Developments in and extension of the applications of physical methods have been so great that physical techniques warranting discussion far exceed the number of Group meetings that can be held.Moreover, the methods and their uses are of such general interest that many of the meetings of this Group might well be meetings of the parent Society and vice versa. I believe, therefore, that the days of the existing Groups are numbered; the interests of two of them are in- sufficiently specialised and those of the other too highly specialised for them to remain as major Groups in the Society of to-morrow-the segregation of interests would be too artificial and unrealistic. Rather do I see a series-and a changing series-of Panels or Discussion Groups that will look after the interests of specialists and ensure that the main and subsidiary meetings of the Society between them give ample coverage to the latest developments and trends in analytical chemistry.Some of these Panels or Groups will be longer lived than others, but whenever a stage is reached at which it becomes an onerous task to scrape together sufficient papers to build what has previously been a customary programme, the function of a Group should be relegated to a watching brief for a new discovery or a resurgence of interest in its specialised field. Thought will have to be given to the place and function of the Analytical Methods Committee of the Society of to-morrow. It has been suggested that the work performed by this Committee and its Sub-committees and Panels, although in keeping with the interests and the activities of the Society of yesterday, does not come within the purview of a learned Society.I believe it right and proper for a learned Society concerned with analytical chemistry to initiate and sponsor investigations designed to evaluate or to improve the reliability of existing or to devise new methods of analysis. But it is also my belief that the investigations it sponsors should extend over a wide area of analytical chemistry and embrace both fundamental and applied problems. The work of the Analytical Methods Committee in the Society of yesterday and to-day has not done this; it has been limited to a narrow field and, in view of the too slowly disappearing impression that the Society’s interests are still only those of the Public Analysts, it is unfortunate that the narrow field is that of food and drugs.Restriction of all but two or three of the Committee’s investigations to food or drugs has not been a matter of choice, because the investigations are prompted by requests put to the Committee, not infrequently by other bodies. The reasons why requests for investi- gations have not come to the Committee from industries other than those concerned with food or drugs should be investigated in the hope that the situation can be rectified, because the scope of the Committee’s researches in the Society of to-morrow must be much wider. It must be much wider not only to preclude its giving a misleading picture of the Society’s interests and status, but also to safeguard the essential financial support it receives from industry.It is unrealistic to expect organisations whose business is in petroleum, heavy chemicals, engineering, rubber, metals and the like to be willing to subsidise heavily researches that rarely extend beyond problems in the analysis of food and drugs. If these industries cannot or do not submit analytical problems to the Committee, then the scope of the investi- gations should be widened by initiating or sponsoring research of a fundamental nature. I am convinced that if in the Society of to-morrow the work of the Analytical Methods Com- mittee continues to be confined within the present narrow limits, the scheme will have an adverse effect upon the reputation of the Society and, moreover, is likely to become but a shadow of its former self through lack of financial support.In planning for the Society of to-morrow, we should not be content to fix our sights at the national level. The Society has 255 overseas members representing 47 nationalities and non-member subscriptions to the Society’s journals come from over 90 countries. This should serve as an incentive for us to formulate our policy for the future with not only the national but the international reputation of the Society in mind. To-day, many of the non-member subscribers to The Analyst and Analytical Abstracts know the Society only as a name that appears on those journals; we should not rest until they and all other analysts throughout the world recognise it as an authoritative body in the field of analytical chemistry that is contributing significantly to the advancement of that branch of science.One means to this end is to make the Society periodically the focal point of a gathering of analysts from all parts of the world. I welcome, therefore, the approval by Council of a plan to hold a Conference on analytical chemistry in 1965. I believe that with dedicated determination The reverse holds good in the Physical Methods Group. This is not my view.May, 19631 ADDRESS OF THE RETIRING PRESIDENT 351 on the part of Council, with an enthusiastic Conference Committee and with the experience of the highly successful conferences that have been held at Oxford, St. Andrews, Edinburgh and Birmingham, this meeting can achieve a success that will be an assurance that the goal of international acceptance of the Society as an organisation of high standing in the field of analytical chemistry is realistic and attainable. The universe of analytical chemistry is expanding at a fascinating speed; so great has been progress in the recent past that looking ahead we can expect to see, in the words of Alexander Pope, “New distant scenes of endless science arise.” The opportunities before us are therefore great, but unless our outlook is continuously anticipatory, the time will come when we shall begin to lose the status we have won. We should be constantly on the watch for developments that attract increasing attention or are likely to do so because of their potentialities so that at an appropriately early stage they can be the subjects of papers in our meetings or journals. If we wait until a new trend in analysis has been established before we provide a platform for it, we shall be too late. On more than one occasion in the past we have thus lost ‘a great opportunity, and specialist groups that might have been part and parcel of the Society have arisen as independent bodies. This should never happen again -the Society should be in the van of the advance and not a camp follower. In bringing to a close this review of the prospects that lie before the Society and steps we can take to bring them to fruition, I would remind you of those lines from Lowell- “New times demand new measures and new men; The world advances, and in time outgrows The laws that in our fathers’ day were best.” Let us hope then that the succession of members through whose hands will pass the formulation and the implementation of policy will be men of vision, men who look from the plains of to-day to the heights of to-morrow. And let us be firmly resolved not to be bound by the shackles of tradition, but ever ready to prune, to reconstruct and to explore.

ISSN:0003-2654    

DOI:10.1039/AN9638800344

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

352 ANNIVERSARY DINNER [Analyst, Vol. 88 Anniversary Dinner IN the evening following the Annual General Meeting, a Dinner to celebrate the eighty-ninth anniversary of the Society was held, by kind permission of the Court of Assistants of the Grocers’ Company, at Grocers’ Hall, Princes Street, E.C.2. The members and guests, number- ing 155, including all the living Past Presidents of the Society, were received by the President, Dr. A. J. Amos, O.B.E., F.R.I.C. and Mrs. Amos. The President afterwards took the Chair at the Dinner. The Guests of the Society and of the President included The Right Honourable the Lord Todd, F.R.S., (Past President of The Chemical Society) and Lady Todd; The Honourable Mr. Justice Lloyd- Jacob, M.A., D.C.L., (Chairman of the Analytical Methods Trust) ; E.Le Q. Herbert, Esq., B.Sc., F.H.-W.C., F.R.I.C., M.I.Chem.E., F.Inst .P., F.Inst .F., (Past President of The Royal Institute of Chemistry) and Mrs. Herbert; S. I. Levy, Esq., Q.C., M.A., Ph.D., F.R.I.C., and Mrs. Levy; D. D. Moir, Esq., M.Sc., F.R.I.C., (President of The Association of Public Analysts) and Mrs. Moir; Mrs. B. Lamb, BSc., F.R.I.C., (Chairman of The Polaro- graphic Society) and Mr. Lamb; M. A. T. Rogers, Esq., B.Sc., Ph.D., F.R.I.C., (Research Controller, Imperial Chemical Industries Ltd.:) and Mrs. Rogers. The Loyal Toast was proposed by the President. Lord Todd, proposing the toast of The Society for Analytical Chemistry, recalled his undergraduate course in inorganic analysis-gravimetric determinations, by text-book methods, of elements in simple solutions, starting with silver nitrate and progressing through the classical qualitative analytical groups of metals.Perhaps this hardy beginning had led him away from analytical into other kinds of chemistry; it certainly had led him to appreciate the skills required of practising analysts. Hut unless a proper training was given, which included arousing an interest in the subject, the profession of analytical chemistry was likely to be short of recruits. This was not simply a task for the Universities or Colleges of Tech- nology, but was one that the Society was particularly well fitted to tackle. He concluded with a tribute to AnaZyticaZ Abstracts, and to the Society for starting when British Abstracts had stopped and thereafter developing Anal3/ticaZ Abstracts into the world’s foremost single- subject abstracting journal.Dr. Amos replied by recalling that in his Presidential Address he had dwelt on the Society’s past, present and future. The Society was as concerned as Lord Todd at the difficulty of getting sufficient analysts, and it intended to show that it had much to offer to those engaged in teaching analytical chemistry, doing fundamental research into the subject and working to solve the analytical problems of industry, commerce and legislation. To this end it was planning closer liaison with the Universities and Technical Colleges, and was reorganising its specialist panel system to cater for all advances in technique as soon as they appeared. Success in this depended on those who gave their time to serve as Members of Council and as Honorary Officers, both of the parent Society and of the Sections and Groups.There was no lack of such voluntary workers and, in paying tribute to them, he felt that the Society’s success was assured. Dr. D. T. Lewis, the Government Chemist and Honorary Treasurer of the Society, proposed the toast of The Guests. Besides the representatives of other Societies, there were present Mr. Justice Lloyd- Jacob-a Bernard Dyer Memorial Medallist of the Society as well as Chairman of the Analytical Methods Trust-and Dr. S. I. Levy, an eminent Queen’s Counsel, who had served in the Ministry of Munitions in the first World War and was Assistant Director of the Ministry of Supply in the second. Also all the living Past-Presidents of the Society were present, making this a unique occasion. Dr. S. I. Levy, Q.C., in reply, alluded to the days when he and Dr. Amos had been Officers of the Chemical Club. He had left chemistry to make himself a career in the Law. He was particularly pleased that Mr. Justice Lloyd- Jacob, Her Majesty’s Special Judge appointed to deal with Patent cases, was present. It had been his privilege and pleasure to appear many times before his Lordship. On behalf of all the guests he thanked the Society for its hospitality. The proceedings concluded with Dr. Amos calling on Dr. D. C. Garratt, the incoming President and Chairman of the Analytical Methods Committee, and investing him with the Presidential Badge. Dr. Garratt presented Dr. Amos with a replica of the Society’s Badge to wear as Past President.

ISSN:0003-2654    

DOI:10.1039/AN9638800352

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

May, 19631 ANDERSON, DUNCAN, HERBICH AND ZAIDI 353 Applications of Infrared Spectroscopy Part X.* The Zeisel Determination of t-Butoxyl Groups, and the Anomalous Reactions of t-Butylphenolst BY D. M. W. ANDERSON, J. L. DUNCAN, M. A. HERBICH AND s. s. H. ZAInI (Department of Chemistry, The University, West Mains Road, Edinburgh 9) Zeisel determinations on t-butoxyl compounds give non-quantitative and variable results. t-Butyl iodide decomposes thermally to isobutene, the equilibrium involved being affected by the reaction variables and by the addition of phenolic compounds. The over-all effect is therefore particu- larly complex for aromatic t-butoxyl compounds, since phenolic compounds are formed within the reaction medium as de-alkylation occurs. Results are presented showing that more satisfactory analyses can be obtained when hydrobromic acid is used in place of hydriodic acid.t-Butyl bromide suffers >2 per cent. decomposition to isobutene when boiled under reflux with constant-boiling hydrobromic acid ; moreover, this decom- position is reproducible under given reaction conditions, and correction factors can therefore be applied. Since t-butoxyl compounds are de- alkylated almost as quickly in hydrobromic acid as in hydriodic acid, the reaction periods required are not significantly longer ; the period required varies from 2 to 3 hours, and is dependent on the nature of the sample. Boiling under reflux with constant-boiling hydrochloric acid offers a method of differentiating between true t-butoxyl compounds and those t-butyl compounds that react anomalously in hydriodic and hydrobromic acids.THE utilisation of t-butyl and t-butoxyl compounds has increased greatly in recent years, e g . , in antioxidants,l,z perfumery chemical^,^ free-radical reaction^,^ 95 graded oxidants697 and in chromatographic separations.8 The relatively easy removalg of t-butyl and t-butoxyl groups makes them useful in reaction intermediatesll and as protective groups in syntheses, e.g., of peptides.12 Steric effect^,^ rearrangement~l~ and instability14115 are factors that combine with the property of ease of removal to complicate the functional analysis of t-butoxyl groups. t-Butylphenols react anomalously in Zeisel determinati~ns,~~ 2 7 and some of the attendant analytical difficulties have been indicated.18 Only a few papers have discussed the application of the Zeisel reaction to butoxyl compounds in general.Of these, only two-so far as we are aware-have quoted results for the tertiary isomer. Houghton and k$7ilson1g reported, without comment, a recovery of only 18-8 per cent. of the theoretical yield of t-butyl iodide from t-butyl alcohol; under different reaction conditions, Kirsten and NilssonZO obtained 60 to 70 per cent. recoveries, and stated that "tertiary butanol appears to give a fairly stable volatile iodide, although the repro- ducibility of recovery is not good." It has long been known that t-butyl iodide is unstable at its boiling-point (103" C), the equilibrium- being established.21 Some decomposition must therefore occur in Zeisel determinations (compare Campbell and Chettleburgh16), in which the reaction temperature is 127" C.In view of the discrepancies between the recoveries reported,lg ,20 a spectroscopicZ2 study of the recovery of t-butyl iodide from reflux in hydriodic acid was undertaken in an attempt to improve the accuracy of determining t-butoxyl groups. It becanie clear that the use of hydriodic acid was analytically unsatisfactory when it was found that: (i) variation of the reaction conditions gave recoveries of t-butyl iodide ranging from 19 to 80 per cent.; (ii) under standardised reaction conditions, the yields of t-butyl iodide were affected by the presence of phenolic compounds in the reaction medium. C,H,tI + C,H, + HI * Part IX appeared in Talanta, 1962, 9, 661. t Presented a t the Joint Meeting of the Scottish and North of England Sections in Belfast, June 28th and 29th, 1962.354 ANDERSON, DUNCAN, HERBICH AND ZAIDI : [Analyst, Vol.88 t-Butoxyl compounds react rapidly23 324 with aqueous hydrobromic and hydrochloric acids, and t-butyl bromide and chloride are more stable thermally than is the iodide; the possibility of basing analytical reactions on boiling under reflux with those acids was therefore investi- gated. EXPERIMENTAL COMPOUNDS- (a) Samples of t-butyl alcohol25 and t-butyl halides conforming to literature description were obtained by redistillation under reduced pressure of reagent-grade commercial samples. Since t-butyl iodide quickly develops a dark colour, small amounts were redistilled daily. Isobutene was prepared by dehydration (with concentrated sulphuric acid) of purified t-butyl alcohol.(b) t-Bzttyl ester-t-Butyl 3,5dinitrobenzoate was prepared; the specimen conformed to literature description. (c) t-Butyl ethers-t-Butyl phenyl ether, t-butyl-$-tolyl ether and t-butyl-1-naphthyl ether were prepared by Grignard reactions with t-butyl perben~oate~~ y2' ; the specimens gave satisfactory elemental analyses (Weiler and Strauss, Oxford). Dark colours developed on storage, and these specimens were redistilled under reduced pressure as required. (d) t-Butylphenols-Samples were supplied by Dr. R. L. Williams, Messrs. Kodak Ltd. and Messrs. I.C.I. (Dyestuffs Division) Ltd. Most of the samples, however, were low-melting solids not readily purified by recrystallisation ; these were purified by zone-melting.APPARATUS, REAGENTS AND PROCEDURE- These have been described,28,29 together with details of (i) the technique for trapping volatile reaction products and (ii) the infrared vapour-phase method for their subsequent identification and determination. Particular care is necessary when transferring the contents of the trap to the gas-cell; t-butyl iodide decomposes so readily that direct warming of the trap over a flame is inadvisable. Satisfactory results were obtained by immersing the trap in water at 80" to 90" C, the sodium chloride cell windows being suitably protected (with plastic covers) during this operation. A slight reaction occurred between t-butyl halides (particularly the iodide) and the sodium chloride cell windows, so that the windows "fogged" much more quickly than usual. The validity of calibration curves had therefore to be checked more frequently than in previous investigations.Liquids were purified by redistillation, U S E OF SOLID SCRUBBERS- Aqueous solutions hydrolyse t-butyl halides to t-butyl alcohol ; hydrolysis of the iodide occurs extremely rapidly.30 It is therefore essential (compare Campbell and Chettleburghle) to use a solid scrubber in determinations of t-butyl halides. Soda asbestos31 has given satisfactory results throughout our studies. EXPERIMENTS WITH CONSTANT-BOILING HYDIZIODIC ACID- (a) Rate of reaction of t-butoxyl compounds-Zeisel determinations were conducted on t-butyl alcohol, t-butyl 3,Ei-dinitrobenzoate and t-butyl-1-naphthyl ether under standard conditions.The conditions were: volume of hydriodic acid, 6 ml (spgr. 1.70, pre-condi- tioned28); nitrogen flow rate, 6 to 8 ml per minute; weight of phenol added, 30 mg. Sample weights yielding 2 to 4 mg of t-butyl iodide were taken. The yields of t-butyl iodide at the reaction times stated were as shown in Table I. Burwell, Elkin and M a ~ r y ~ ~ have already commented on the fact that ethers are not always less reactive than alcohols. (b) Recovery of t-butyl iodide-Samples of t-butyl iodide (in small weighing bottles fitted with ground-glass stoppers-see Anderson and Duncan2s) were placed in the Zeisel reaction flask; the recovery from boiling under reflux in hydriodic acid was investigated, the reaction conditions being the same as those out-lined in (a) above.The maximum recovery varied from 58 to 80 per cent. ; about 80 per cent. of the total recovery in each determination distilled within 20 minutes. For fixed weights of samples of t-butyl iodide, small variations in recovery RESULTSMay, 19631 APPLICATIONS OF INFRARED SPECTROSCOPY. PART X TABLE 1: YIELD OF t-BUTYL IODIDE FROM DIFFERENT COMPOUNDS Yield of t-butyl iodide (as percentage of theoretical) Compound After reflux for After reflux for After reflux for r A 1 1 hour 2 hours 3 hours t-Butyl 3,5-dinitrobenzoate . . . . 76.0 80.8 (max.) - t-Butyl-l-naphthyl ether . . .. 40-5 66.6 (max.) - 1st determination 42.5 48.7 56.6 (max.) t-ButY1 { 2nd determination 39.5 45.0 60-9 (max.) 355 resulted when: (i) the volume of hydriodic acid was decreased from 6 to 1 ml, (ii) the flow rate was varied from 4 to 12 ml per minute and (iii) the weight of phenol was varied from 0 to 100mg.Little variation in the rate of recovery was found when the temperature of the condenser water was increased (compare Belcher, Fildes and Nuttens and InglisM). (c) Production of isobutene-In all these determinations some isobutene was produced, the sum of the molar recoveries of t-butyl iodide and isobutene accounting for the t-butyl iodide taken. A time - recovery experiment with 2,6-di-t-butyl-4-methoxyphenol in which Campbell and Chettleburgh’s16 experimental conditions were used gave results agreeing well with those reported16; boiling under reflux for 1 hour gave the theoretical yield of methyl iodide, together with isobutene and a yield of t-butyl iodide that, calculated as methyl iodide, gave an apparent methoxyl content of 21 to 22 per cent.The ratio of the molar yields of isobutene and t-butyl iodide was, however, constant over the whole reaction period, e.g., boiling under reflux for 10 minutes gave approximately 70 per cent. of the total yield of isobutene and also approximately 70 per cent. of the total yield of t-butyl iodide. This does not support Campbell and Chettle- burgh’s implication16 that the isobutene results from decomposition of some t-butyl iodide that does not distil in the earlier stages of the reflux period. The molar ratio of isobutene to t-butyl iodide (i.e., the extent of decomposition of the t-butyl iodide) was also much greater than in any of our previous experiments. It was suspected that this resulted from the changes made in the reaction conditions in order to duplicate Campbell and Chettleburgh’s experiments.16 These workers, in testing scrubber effects, determined the total apparent methoxyl content of 2-t-butyl-4-methoxyphenol under four different reaction conditions, and found four different values ranging from 18.06 to 22-56 per cent.This range was confirmed when these experiments were repeated with a solid scrubber. Changes in reaction conditions, and not scrubber hydrolysis effects, therefore cause the variable results. (d) Variation in yield of t-butyl iodide with reaction conditions-In a series of experiments, a constant weight of t-butyl-4-hydroxyanisole (mixed 2 and 3 isomers) was allowed to react under different conditions; these are shown, together with the yields of t-butyl iodide obtained, in Table 11. Further experiments showed that cresols and other phenolic compounds caused similar variations in the results.The conjoint addition of other solubilisers, such as propionic anhydride and hypophosphorous acid, further complicated the effect. Other experiments indicated that phenolic compounds, formed in the reaction medium during the de-alkylation reaction, contributed to the decomposition of t-butyl iodide. (1) t-Butyl-4-hydroxyanisole (5 mg) was allowed to react in hydriodic acid (6 ml), with no added phenol. The recovery of t-butyl iodide was 80 per cent,, in agreement with the result This effect was further investigated as described below. TABLE 11: YIELD OF t-BUTYL IODIDE FROM 5-mg SAMPLES OF BUTYLATED HYDROXYANISOLE UNDER DIFFERENT REACTION CONDITIONS Nitrogen flow rate, ml per minute 4 4 6 to 8 6 t o 8 6 to 8 6 to 8 6 to 8 12 t o 15 Hydriodic acid (sp.gr.1.70) used, ml 1 6 1 6 6 6 6 1 Phenol added, mg 30 30 10 0 10 30 60 30 Yield (as percentage of theoretical) 19 51 53 80 72 62 50 45356 ANDERSON, DUNCAN, HERBICH AND ZAIDI : [Analyst, Vol. 88 in Table 11. (2) The reaction medium was boiled for a further 4 hours to eliminate all traces of alkyl iodides, and the mixture was then cooled. A further 5 mg of sample and 30 mg of phenol were added; the recovery of t-butylphenol was 52 per cent., compared with 62 per cent. (see Table 11) for the corresponding “straight” reaction with 30 mg of phenol. (3) The reaction medium was again boiled for 4 hours, and then cooled; a further 5 mg of sample and 30 mg of phenol were added.The recovery of t-butyl iodide was then only 42 per cent., compared with 50 per cent. for 60 mg of phenol in Table 11. Thus the effect of the total phenol added (60mg) was apparently augmented by the sum (approximately 6mg) of the weights of phenolic compounds formed in determinations (1) and (2). EXPERIMENTS WITH CONSTANT-BOILING HYDROBROMIC ACID- (a) Recovery of t-butyl bromide-When 6 ml of hydrobromic acid, 30 mg of phenol and a nitrogen flow rate of 6 to 8 ml per minute were used, the recovery of samples (2 to 5 mg) of t-butyl bromide after boiling under reflux for 1 hour was 90.7 per cent. and, after 2 hours, 98-4 per cent. (maximum yield). An equilibrium of the form- C,H,tBr + C,H, + HBr must exist,35 but under the stated reaction conditions (reflux temperature 115” C) the extent of decomposition to isobutene does not exceed 2 per cent.Indeed, only traces of isobutene were detectable in the infrared spectrum of the reaction products ; some polymerisation35 of isobutene may occur. The recoveries of t-butyl bromide were reproducible and were not strongly influenced by small changes in reaction conditions or in the amounts of phenol added. (b) Rate of reactioa of t-butoxyl compowds-With use of the same reaction conditions as in (a) above, the rate of evolution of t-butyl bromide from some t-butoxyl compounds was determined. The reaction time required varies from 2 to 3 hours, depending on the compound being analysed.When these results are corrected by +1-6 per cent. (the percentage loss of t-butyl bromide during recovery), only the results for two of the ethers are slightly low; this may well reflect the state of purity of these specimens. (c) The anomalous reaction of t-butyZ@mZs-Some t-butylphenols were boiled under reflux in constant-boiling hydrobromic acid for 2 to 3 hours. Nearly quantitative yields of t-butyl bromide were produced. Such compounds cannot therefore be distinguished from t-butoxyl compounds by this reaction. The results are shown in Table 111. TABLE 111: YIELD OF t-BUTYL BROMIDE FROM t-BUTOXYL COMPOUNDS Yield of t-butyl bromide (as percentage of theoretical) 1 hour 2 hours 3 hours 7 A -I Compound After reflux for After reflux for After reflux for t-Butyl alcohol.. . . .. . . 95.4 98.3 (max.) - t-Butyl 3,Ei-dinitrobenzoate . . . . 97.0 98.6 (max.) - t-Butyl phenyl ether . . , . . . 86-5 91.1 96.2 (max.) t-Butyl-p-tolyl ether . . . . . . 86.8 93.3 95.6 (max.) t-Butyl-l-naphthyl ether . . . . 90.8 93.6 97.5 (max.) EXPERIMENTS WITH CONSTANT-BOILING HYDROCHLORIC ACID- Under the reaction conditions specified in “(a) Recovery of t-butyl bromide” above boiling under reflux with constant-boiling hydrochloric acid for 2 hours gave the results listed below. (a) Recovery of added t-butyl chloride was nearly quantitative (>98 per cent.) (compare Kistiakowsky and StauffeP). (b) t-Butyl alcohol and t-butyl 3,5-dinitrobenzoate gave 98 per cent. of the theoretical yields of t-butyl‘ chloride. (c) t-Butyl ethers gave 60 to 65 per cent.of the theoretical yield of t-butyl chloride. (d) The reactions of the t-butylphenols were- (i) No t-butyl chloride formed- 2,4-di-t-butylphenol; 5-methyl-2-t -butyl-4,6-dinitroanisole ; 4-t -butylphenol.May, 19631 APPLICATIONS O F INFRARED SPECTROSCOPY. PART X (ii) <lo per cent. of t-butyl chloride formed- 5-met h yl-2- t -but ylphenol ; t-butylated-4hydroxyanisole (mixed 2 and 3 isomers) ; 2,6-di-t-butylphenol. (iii) <20 per cent. of t-butyl chloride formed- 2,4-dimethyl-5-t-butylphenol; 3-methyl-4,6-di-t-butylphenol. 357 CONCLUSIONS Boiling under reflux with constant-boiling hydrobromic acid is a satisfactory method of analysis for t-butoxyl groups. Under the reaction conditions described, decomposition of t-butyl bromide does not exceed 2 per cent., and the appropriate correction factor can be applied to the analytical results.The reaction period varies from 2 to 3 hours, depending on the compound being analysed. When the infrared method of determinationz2 is being used, prolongation of the reaction period is not critical, although this might be inadvisable for volumetric or gravimetric determinations of the t-butyl bromide. Roiling under reflus with constant-boiling hydrobromic acid does not distinguish between true t-butoxvl compounds and t-butylated phenols. Boiling under reflux with constant-boiling hydrochloric acid, however, offers a method of making this distinction. The yields of t-butyl chloride vary from 60 to 98 per cent. for t-butoxyl compounds, and from 0 to 20 per cent. for the range of t-hutylphenols studied.I t is possible that a rearrangementz7 of the form- 0 H I I oc, N !) t occurs in acid solution, the extent of the rearrangement depending on the concentration of acid and the nature of the substituent groups and substitution pattern in the phenolic compound. The results presented show clearly that boiling under reflux with hydriodic acid does not give a satisfactory analytical reaction for t-butoxyl groups. The equilibrium- C,H,tI + C,H, + HI is clearly dependent on the ratio of sample weight to volume of acid used, on the flow rate of scavenging gas and on the amounts of phenolic compounds added as solubilisers or formed within the reaction medium during the de-alkylation reaction. Our results indicate that production of isobutene does not increase markedly in the latter stages of a determination ; there is no extensive decomposition of undistilled portions of t-butyl iodide.In the recovery of t-butyl iodide, the yield varied from 58 to 80 per cent. and was not strongly dependent on changes in flow rate or on the addition of phenolic compounds. The rate of distillation was rapid (approxi- mately 80 per cent. in 15 minutes), and the recovery of added t-butyl iodide appears to be mainly dependent on the thermal decomposition equilibrium. In the formation of t-butyl iodide from t-butoxyl compounds, however, several striking differences are apparent. (a) The relative yields of t-butyl iodide vary much more widely (19 to 81 per cent.); (b) the rate of distillation (now dependent on the rate of formation) is much slower (approximately 50 per cent.in 1 hour); (c) the relative amounts of t-butyl iodide and isobutene formed are strongly dependent on the reaction conditions, and, particularly, on the presence of added compounds. Mechanisms of the reactions of t-butyl compounds have been extensively studied,37 938 and the relative stability of the t-butvl carbonium ion is well known. Olefine-forming Two effects must be distinguished.358 ANDERSON, DUNCAN, HERBICH AND ZAIDI [Analyst, Vol. 88 elimination reactions involving butyl compounds proceed via competitive S,1 and El uni- molecular reactions, in which the rate of formation of the carbonium ion (step (a) below) is rate-determining. CH, CH3 ‘\, CH, CH, I t appears that the relative extent to which reactions ( b ) and (c) occur in Zeisel deter- minations is dependent on the reaction conditions and additives employed.We are grateful to Dr. R. L. Williams, Ministry of Aviation, Waltham Abbey, Essex, Messrs. Kodak Ltd., Kirkby, Lancs., and Messrs. I.C.I. (Dyestuffs Division) Ltd. for providing specimens of t-butylphenols. We thank the P.C.S.I.R., Karachi, for granting study leave and financial assistance to one of us (S.S.H.Z.). 1. 2. 3. 4. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 3. REFERENCES Rosenwald, R. H., Hoatson, J.’ R., and Chenicek, J. A., I n d . Eng. Chem., 1950, 42, 162. Kim, D. H., and Kummerow, F. A., J . Amer. Oil Chem. SOC., 1962, 39, 150. Ferrero, C., and Helg, R., Helv. Chim.Acta, 1959, 42, 2111. Cook, C. D., and Gilmour, N. D., J . Org. Chem., 1960, 25, 1429. McGowan, J. C., and Powell, T., J . Chem. SOC., 1960, 238. Cook, C. D., Depatie, C. B., and English, E. S., J . Org. Chem., 1959, 24, 1356. Menini, E., and Norymberski, J . K., Biochem. J . , 1962, 84, 195. Mazur, R. H., Ellis, B. W., and Cammarata, P. S., J . Bid. Chenz., 1962, 237, 1619. Bell, F., J . Chem. Soc., 1958, 120. Ireland, R. E., and Chaykovsky, M., in Roberts, J . D., Editor-in-Chief, “Organic Syntheses,” Klee, W., and Brenner, M., Helv. Chim. Acta, 1962, 44, 2151. Beyerman, H. C., and Bontekoe, J. S., Rec. Trav. Chim., 1962, 81, 691. Roberts, J. D., McMahon, R. E., and Hine, J . S., J . Amer. Chem. SOC., 1950, 72, 4237. Smutny, E. J., and Bondi, A., J .Phys. Chem., 1961, 65, 546. Howe, J. H., and Morris, L. R., J . Org. Chem., 1962, 27, 1901. Campbell, A. D., and Chettleburgh, V. J., Analyst, 1959, 84, 190. Anderson, D. M. W., and Duncan, J. L., Chem. & Ind., 1959, 457. -- , Talanta, 1962, 9, 661. Houghton, A. A,, and Wilson, H. A. B., Analyst, 1944, 69, 363. Kirsten, W. J., and Nilsson, S. K., Mikrochim. Acta, 1960, 983. Jones, J. L., and Ogg, R. A., J . Amer. Chem. SOC., 1937, 59, 1943. Anderson, D. M. W., Analyst, 1959, 84, 50. Gerrard, W., and Whitbread, E. G. G., J . Chem. SOC., 1952, 914. Norris, J. F., and Rigby, G. W., J . Amer. Chem. SOC., 1932, 54, 2088. Maccoll, A., and Stimson, V. R., J . Chem. SOC., 1960, 2836. Frisell, C., and Lawesson, S., in Roberts, J. D., Editor-in-Chief, o f . cit., p. 91. Beringer, F. M., Forgione, P. S., and Yudis, M. D., Tetrahedron, 1960, 8, 49. Anderson, D. M. W., and Duncan, J. L., Talanta, 1960, 7, 70. _ _ - , Ibid., 1961, 8, 1. Moelwyn-Hughes, E. A., J . Chem. SO~., 1962, 4301. Anderson, D. M. W., and Duncan, J . L., Chem. & Ind., 1959, 1151. Burwell, R. L., Elkin, L. M., and Maury, L. G., J . Amer. Chem. SOC., 1951, 73, 2428. Relcher, R., Fildes, J. E., and Nutten, A. J., Anal. Chim. Acta, 1955, 13, 16. Inglis, A. S., Mikrochim. Acta, 1957, 677. Howlett, K. E., J . Chem. SOL., 1957, 2834. Kistiakowsky, G. B., and Stauffer, C. H., J . Amer. Chem. SOC., 1937, 59, 165. Ingold, C. K., “Structure and Mechanism in Organic Chemistry,” Bell and Sons, London, 1953. Dostrovsky, I., and Klein, F. S., J . Chem. Soc., 1955, 791. Received December 17th, 1962 John Wiley and Sons Inc., New York, 1961, Volume 41, p. 5.

ISSN:0003-2654    

DOI:10.1039/AN9638800353

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

May, 19631 ADEY 359 A Cryoscopic Method for assaying Pyridine BY K. A. ADEY (The Midland Tar Distillers Ltd., Four Ashes, nr. Wolverhampton) A niethod is described suitable for the routine assay of pyridine. Water present in the original sample or absorbed during the assay has an abnormal effect on the freezing-point, and errors arising from this source are overcome by applying a correction based on the water content of the sample a t the end of the test. The depressions of the freezing-point of pyridine caused by additions of up to 6 moles per cent. of m-picoline, p-picoline, y-picoline, 2,6-lutidine and benzene have been measured; these substances include all the major impurities likely to be present in pyridine derived from natural or synthetic sources. For each of the compounds added the depression of the freezing- point was linear over the range examined, and the values of the cryoscopic constant were identical within the limits of error of the experimental procedure.Within the range of our experiments, therefore, the accuracy of the method is not dependent on the composition of the sample, and the single equation presented relating freezing-point to purity can be used with confidence for the assay of pyridine from natural or synthetic sources. Results of an inter-laboratory co-operative programme for determining the precision of the method are reported. IN 1959 Adey and Cox1 described a method, based on solution temperature in aqueous potassium chloride, for determining small amounts of a-picoline in pyridine. If the assump- tion is made that a-picoline and water are the only contaminants of commercial pyridine, the procedure affords a precise and accurate measure of the purity of this chemical.However, there is always the possibility that other bases may be present. It is known, for example, that one synthesis of pyridine also yields P-picoline, and we have found that the depression of the solution temperature of pyridine is 1.09" C per 1 per cent. w/w of P-picoline fraction compared with 0.70" C per 1 per cent. w/w of a-picoline present. Further, the effect of benzene, which may be used in the azeotropic dehydration of pyridine, is some 10 times as great as that of a-picoline (6.9" C per 1 per cent. w/w of benzene). Later, a simple cryoscopic method for assaying /3-picoline, y-picoline and 2,6-lutidine was reported.2 During this work it was found, as might be expected, that the bases formed ideal solutions in so far as there were no significant differences in the depression of the freezing-point of a given base by several different basic impurities.Thus, for example, the separate depressions of the freezing-point of y-picoline produced by 1 mole per cent. of each of four different impurities (a-picoline, P-picoline, 2,4-lutidine and 2,6-lutidine) ranged from 0.537" to 0.550" C. It was concluded, therefore, that the freezing-point was a better criterion of purity in that it was less sensitive to the nature of the basic impurities present. The adaptation of the method to pyridine posed various problems, among them the necessity to work at a much lower temperature, about -42" C, than with the picolines, and the inability to use a mercury thermometer at this temperature, but these were solved more easily than was a t first expected.Thermometers having the mercury - thallium eutectic as the indicating liquid were readily obtained to special order, and unqualified assistants found no difficulty in working with a cooling bath at -48" to -50" C. EXPERIMENTAL PURIFICATION OF BASES- Samples of P-picoline, y-picoline and 2,6-lutidine were purified by slow fractional freezing as described by Biddiscombe, Coulson, Handley and Heringt~n,~ the process being repeated until no further rise in freezing-point was observed. The freezing-points of the purified bases were within 0.1" C of the values reported by these authors for the pure bases.The freezing-points of pyridine (-42" C) and a-picoline (-67" C) were too low for the same procedure to be adopted with the apparatus at our disposal. These bases were therefore purified by high-efficiency fractional distillation of the commercially pure products. This we considered adequate for our purpose.360 ADEY: A CRYOSCOPIC METHOD FOR ASSAYING PYRIDINE [Analyst, Vol. 88 The pyridine submitted to this treatment was assayed at 99 per cent. purity by the solution-temperature meth0d.l The cc-picoline used had a boiling range of 1.7" C (drop to dry). A glass fractionating column was used; this was 5 feet long by 1 inch internal diameter. It was packed with 1/16-inch x l/l6-inch Dixon gauze rings and surrounded by an air jacket with electric heaters for temperature compensation.Take-off was controlled by an electronically operated vapour-dividing still head and boil-up was measured with a conven- tional boil-up meter interposed between the still and the cohmn. Two litres of a-picoline were placed in the still and distilled a t a boil-up of 1000 ml per hour and a reflux ratio of 50 to 1. The first 20 per cent. by volume of distillate was rejected and the next 60 per cent. by volume collected for use. Analysis by gas - liquid chromato- graphy showed no compounds other than cc-picoline. The pyridine was distilled in a similar way. The final product had a freezing-point of -41.8" C. Its purity as determined by the solution-temperature method was 99.7 moles per cent. DEPRESSION OF FREEZING-POINT BY WATER- Because of our experience with the picolines and 2,6-lutidine, which we found to be extremely hygroscopic,2 no attempt was made to prepare solutions of known amounts of water in pyridine.Instead a suitable amount of water was added to pyridine, and the freezing-point of the mixture was determined. The concentration of water present at the end of the determination was measured by the Karl Fischer method. In one series of experiments the mixtures used contained approximately 0.05, 0.1, 0.2, 0.4 and 0.6 per cent. of water in pyridine. Their freezing-points and water contents were measured by the procedure described below. The determinations were repeated on a second series of samples containing 0.02 to 0.9 per cent. of water. As with the picolines, a graph of water content against depression of freezing-point was linear within the range examined.DEPRESSION OF FREEZING-POINT BY BASIC IMPURITIES AND BENZENE- Weighed amounts of each impurity in turn were added to weighed amounts of pyridine (see Table I). The water contents of all the substances used were determined, and the molar concentration of dry impurity in the total dry mixture was calculated for each mixture in turn. The freezing-points were converted to a dry basis by determining the water content at the end of the test and applying the appropriate correction from the graph described above. Water contents were kept as low as possible in order to minimise the correction, and were in every instance less than 0.1 per cent. TABLE I CONCENTRATIONS OF IMPURITIES IN PYRIDINE Range of concentration, Impurity moles per cent.a-Picoline . . . . . . 0.0 to 4.9 icoline . . . . . . 0.0 to 5.3 . . . . 0.0 to 5.9 y-Picoline . . 2,g-Lutidine . . . . . . 0.0 to 3.9 Benzene.. . . . . . . 0.0 to 4.9 P-p: METHOD APPARAT u S- The freezing-point apparatus is of tlie conventional type and consists of an inner test- tube, 150mm x 25mm, fitted concentrically by means of a cork inside a wider tube, 150 mm x 40 mm, that acts as an air-jacket. The inner tube is closed by a cork fitted with a suitable thermometer (see below) and a glass stirrer. The stirrer is a glass rod about 3 mm in diameter bent at its lower end into a loop at right angles to the axis of the rod. This loop is of suitable diameter (about 18mm) to surround the stem of the thermometer and move easily up and down the inner tube. The thermometer is centrally placed in the cork and so positioned that the bottom of its bulb is about 1 cm above the bottom of the inner test-tube.The cooling liquid is contained in a Dewar jar, internal diameter about 100 mm, to mini- mise absorption of heat from the atmosphere.May, 19631 ADEY: A CRYOSCOPIC METHOD FOR ASSAYING PYRIDINE 361 Apparatus for the determination of water content by the Karl Fischer method is also required. THERMOMETERS- Two thermometers have been used. Both were calibrated for 100-mm immersion, subdivided to 0.1" C and had N.P.L. certificates or the maker's Works Certificates quoting corrections with an error of 0.1" C for temperatures above -45" C. (i) Range -46" to -34" C and -0.5" to +04" C, made by Short & Mason Ltd., (ii) Range -55" to -25" C, made by H.J. Elliott Ltd., E-Mi1 Works, Pontypridd, London. Glamorgan. PROCEDURE- Place in the Dewar jar an amount of cooling mixture such that, when the apparatus is assembled, the level of liquid in the jar is at least as high as the level of the sample in the inner test-tube. Adjust the temperature of the mixture, immediately before use, to between 6" and 8" C below the expected freezing-point of the sample. A suitable cooling mixture can be prepared from solid carbon dioxide and ethanol. Place approximately 25 ml of the sample to be tested in the inner test-tube. Fit the stirrer and thermometer in the inner test-tube, and pre-cool the sample, with stirring, to about 5" C above the expected freezing-point.Rapidly dry the outside of the test-tube, and fit it centrally inside the air-jacket already in place in the cooling bath. Stir gently and continuously, and read the thermometer at 30-second intervals (estimate the temperature to 0.01" C). When the temperature has fallen to the expected freezing-point, introduce a seed crystal as rapidly as possible, and continue the test. (The seed crystal can be conveniently introduced by raising the stirrer to its highest extent, without removal of the cork from the inner test-tube, and depositing a crystal from a glass rod as low as possible on it. The stirrer is then replaced in the liquid and stirring is continued). The freezing-point corresponds to the first set of four consecutive readings during which the temperature remains constant.If supercooling occurs, the constant tem- perature will be observed after the temperature rise. A temperature rise of 1" C is the maximum permissible; if it exceeds this value, repeat the determination on a fresh portion of the sample. Record the observed freezing-point, F, corrected for any scale error of the thermometer. Remove the inner test-tube, complete with thermometer and stirrer, without delay, and heat rapidly, with stirring, until the temperature rises to between 14" and 16" C. By pipette, preferably with use of a pipette filler, withdraw 20 ml of sample, and determine its water content (per cent. w/v). Calculate the corrected freezing-point, F,, for the dry substance by adding an amount 2-30 w, where w is the water content (per cent.w/v). Calculate the purity of the dry sample, Po, from the expression- (-41.62 - 1'0) 0.594 Yo, mole per cent. == 100 - Alternatively, if the impurities are known to be picolines, the percentage w/w purity, P,, can be calculated from- (-41.62 - Fo) 0.505 Pu, per cent. w/w 7 100 - If many samples are to be tested, it is much more convenient to prepare graphs from these expressions and also of 2.30 w. RESULTS The depression of the freezing-point of pyridine by water was calculated by the method of least squares for each series of mixtures.362 ADEY A CRYOSCOPIC METHOD FOR ASSAYING PYRIDINE [A%dyd, VOl. 88 The equations for the regression lines are- (i) Fo == -41.82 - 2.321 W ; s = 0.091 (ii) Fo = -41.77 - 2.284 zet; s = 0.074 where F, = observed freezing-point, "C, corrected for scale errors of the thermometer, w = water content at the end of the test, per cent.w/v, and s = standard error of the regression coefficient. The effects of basic impurities and benzene on the freezing-point of pyridine are shown in Table 11. TABLE I1 DEPRESSION OF FREEZING-POINT OF PYRIDINE BY OTHER BASES AND BENZESE Depression of freezing-point (8) caused by 1 mole per cent. Standard Number of Impurity of impurity,* "C error of 6 observations cc-Picoline . . . . 0.5824 0.012 8 B-Pjcoline . . . . 0.5963 0.016 8 y-Picoline . . . . 0.5880 0.01 5 A 2,6-Lutidine . . . . 0.5534 0.022 Benzene . . . . 0.5613 0.013 G of dry impurity. F * Mixture consists of 99 moles per cent. of dry main component and 1 mole per cent DISCUSSION OF RESULTS A statistical examination of the values of the depression of the freezing-point (8) and its standard error, S.E.(O), for the bases in Table 11, showed that the values of 8 did not differ significantly from each other. The over-all regression coefficient for bases and its standard error were therefore calculated and, in addition, the over-all regression coefficient for the three picolines, i.e., excluding the value for 2,6-lutidine. The results of the calculations are shown in Table 111. TABLE I11 VALUES OF THE OVER-ALL REGRESSION COEFFICIENTS e S.E. (8) Number of observations All bases . . .. . . 0.5954 0.0070 23 Picolines only . . . . 0.5943 0*0055 18 Although the regression line for 2,6-lutidine has the lowest value of slope, the inclusion of the results for this base increases rather than decreases the regression coefficient for the combined results.The difference between the values of the slopes is, however, without significance; it arises from the reduction in weight given to the freezing-point of pure pyridine (which is common to all the regression lines) when the several sets of results are combined. The value for benzene (8 = 0.5613) was not included in the calculation of the over-all coefficient, since benzene is not a usual contaminant of pyridine, but may occur, e.g., through malfunctioning of an azeotropic dehydration unit. The results show that the presence of small amounts of benzene will not vitiate an assessment of the purity of a sample of pyridine from its freezing-point. The method described here does not therefore suffer from the disadvantages of the solution-temperature method in this respect. Biddiscombe, Coulson, Handley and Heringt~n,~ who used iso-octane as the impurity, obtained a value of 0.607" & 0.017" C for the depression of the freezing-point of pyridine by 1 mole per cent.of impurity. The same workers reported a freezing-point of -41.55" 0.05" C for 100 per cent. pyridine. A later personal communication from Dr. Herington gave -41.62" 0.0" C as the best estimate for the pure base, and this value has been used in the expression on p. 361 for calculating the molar purity from the freezing-point. It will be noted that the denominator of this expression is 0.594, that is, the value of 0 corresponding to the picolines only.Although there are theoretical reasons for preferring this value to the over-all value of 0.595, the difference is, as stated above, without significance, The results given here agree closely with this figure.May, 19631 ADEY: A CRYOSCOPIC METHOD FOR ASSAYING PYRIDINE 363 and substitution of the latter value does not give rise to a significant difference over the range of purity under discussion. A freezing-point of -4459" C, for example, corresponds to 5-00 moles per cent. of impurity when 8 = 0-594 and to 4.99 moles per cent. when 8 = 0.595. This method has been adopted by the Standardisation of Tar Products Tests Committee in its handbook4 and the Tar Bases Panel of that Committee has carried out an inter-laboratory co-operative programme to determine the precision of the method.They found a repeat- ability of 0.20" C, corresponding to 0.34 moles per cent. of pyridine, and a reproducibility of 060" C, corresponding to 0.85 moles per cent. of pyridine. These are 95 per cent. confidence limits, and in the long run of properly conducted tests the majority of pairs of results will differ by much less than these amounts. The repeatability and reproducibility are expected to improve further as the operators become more familiar with the test. Results obtained in the laboratories of the Midland Tar Distillers show good agreement between the solution-temperature1 and freezing-point methods, as the results in Table IV show. TABLE IV COMPARISON OF SOI.~TIO~-TEMPEHATURE .4SD FREEZING-POINT METHODS Solution temperature (S.T.), 'C: 26-84 26.72 26.38 26.48 26.40 26-15 26.1 1 26.27 26.45 28-56 26.19 Freezing-point (F.P.), "C -41.85 -41.78 -41.86 -42.10 - 42.08 - 42.16 -42.19 -42.14 - 42.03 -41.98 -42.19 Purity calculated from- 7 - 7 S.T., F.P., Difference 0" w,tw yo w/w S.T. - F.P. 99.49 99-54 - 0.05 99.60 99.68 - 0.08 99.40 99.52 -0.12 99.26 99.05 +0*21 99.14 99.09 + 0.05 98.79 98.93 -0.14 98.73 98-85 -0.14 98.96 98.97 -0.01 99.2 1 99.19 + 0.02 !39.37 99.29 - 0.08 98.84 98-87 + 0.07 I acknowledge the help cf Mrs. S. Walker and Mrs. M. MacIntyre, by whom most of the practical work was done, and thank the Directors of The Midland Tar Distillers Ltd., Oldbury, for permission to publish this paper. REFERENCES 1. Adcy, 1;. .I., and Cox, J . l)., Atzalyst, 19.59, 84, 414. 2. 3. 4. Adey, I<. A4., Ibid., 1959, 84, 560. Biddiscombc, 1). P., Coulson, E. A., Handley, R., and Herington, I?. I;. G., J . Chem. SOC., 1954, Watkins, P. T'., Editor, "Standard Methods for Testing Tar and its Products," Fifth Edition, Received 1L'ovemb~v 12th, 1962 1957. Standardization of Tar Products Test Committee, Gomersal, T-eeds, 1962.

ISSN:0003-2654    

DOI:10.1039/AN9638800359

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

364 COMMIES: DETERMINATION OF PARTICULATE ACID I N TOWN AIR [Analyst, VOl. 88 Determination of Particulate Acid in Town Air BY B. T. COMMINS (Medical Research Council, Air Pollution Research Unit, St. Bavtholomsw’s Hospital Medical Coilegz, London, E.C.l) A method for measuring particulate acid in town air by titration was investigated and found to be suitable. Particulate matter of the air was collected by filtration, and the amount of acid determined by immersing the collected sample in a known excess of 0.01 N sodium tetraborate in de-ionised water at pH 7 and titrating back to pH 7 with 0.01 N acid. The particulate acid in the air of the City of London appeared to be mainly sulphuric. VARIOUS workers have studied the acidity of urban air since regular observations of atmos- pheric pollution began in 1913.They all recognised that the main gaseous acid, apart from the carbon dioxide, in air was sulphur dioxide, but they also identified sulphuric acid in the suspended matter. Ellis1 measured the total acid in London air by titration after absorbing both sulphur dioxide and particulate acid in hydrogen peroxide; he determined the sulphur dioxide alone by an iodine method and the concentration of particulate acid by subtraction. Goodeve2 used sintered-glass discs to filter out the acid, and Coste and Courtier3 devised a technique in which the acid droplets were made to grow before collection. The general conclusion at that time was that the amount of particulate acid present in urban air was extremely small in comparison with the amount of sulphur dioxide.With the advent of “smog” in Los Angeles, interest in acid droplets was revived, and Mader, Hamming and Bellin4 used washed filter-papers to collect acid droplets there. A11 these investigators found significant amounts of acid only in fog. In the London fog of December, 1952, sulphur dioxide but not particulate acid was measured; this episode revived interest in the subject. When suspended matter in London air is collected by impaction on glass slides coated with gelatin containing thymol blue and viewed under a microscope, strongly acidic droplets can be seen as pink spots.5 This method is, however, only qualitative, and, of the various procedures for determining acid, the titration of air solids collected on a filter-paper was found to be the most suitable.METHOD DETERMINATION OF PARTICULATE ACID- Samples for analysis are collected on 4.25-cm circles of Whatman No. 1 filter-paper held in a Perspex holder so that a 1-inch circle of the filter-paper is exposed. Air-flow rates of up to 30 litres per minute are used, and samples are usually taken over periods of up to 6 hours. At times of high pollution, a one hour sample representing 1 cu. metre of air was adequate for analysis. A solution of bromothymol blue in de-ionised water is prepared by adding 4 ml of a 0.1 per cent. solution of the indicator in alcohol to 100 ml of de-ionised water. To this solution sufficient 0.01 N sodium tetra- borate is added to make it a stable apple-green colour (pH approximately 7). After the outer unexposed edges of the filter-paper have been cut off, the sample is cut into two exactly equal portions, one portion being added to 1 to 2 ml of the solution and titrated with 0.01 N sodium tetraborate to the original green colour.A similar beaker containing the same volume of the solution is kept as a control, since this liquid absorbs any sulphur dioxide from the air and slowly changes colour. During titration the solution is agitated by vigorous swirling, and it is found that the end-point is reached after about 5 minutes. This end-point is shown by a stable green colour identical to that of the control solution. The amount of acid indicated by this method is too low, since some of the acid reacts with water-insoluble bases present in the sample. The true amount of acid is found by adding a known excess of 0.01 N sodium tetraborate (at least 0.1 ml more than the amount The method involves titration of filter-papers to pH 7.May, 19631 COMMINS: DETERMINATION OF PARTICULATE ACID IN TOWN AIR 365 indicated above) to 1 to 2 ml of the pH 7 solution and then immersing the second portion of the filter-paper in it and titrating the excess with 0.01 N sulphuric acid.Then the concen- tration of acid (calculated as sulphuric acid) in pg per cu. metre of air = 98,000 x -, where V NU N = normality of sodium tetraborate (0-01 N), ZI = equivalent volume (in ml) of 0.01 N sodium tetraborate used to neutralise the acid V = volume of air sampled (cu. metres). during back titration of half the sample filter-paper, and STORAGE OF SAMPLES- Samples become neutralised when left in air, and they should therefore be titrated as soon as possible after collection. Samples are neutralised more readily indoors than outdoors and only slowly when sealed in polythene bags.Tests have shown that, outdoors, losses of acid varied between 0 and 30 per cent. over 5 days. For the same period indoors, losses up to 70 per cent. occurred owing no doubt to greater amounts of ammonia being present. Samples kept in polythene bags showed a loss of about 50 per cent. over a period of one year. DISCUSSION AND JUSTIFICATION OF METHOD Many substances other than sulphuric acid are present in air. Possible interferences in the method were examined and are discussed below. INTERFERENCE BY ACIDIC GASES- Carbon dioxide, nitrogen dioxide and sulphur dioxide are all present in polluted air.Carbon dioxide is an extremely weak acid, is not appreciably absorbed by filter-paper and therefore does not interfere with the method. Nitrogen dioxide, even if it were absorbed by filter-paper during collection, is insufficiently absorbed by water to affect the measurement of sulphuric acid. To assess the interference by sulphur dioxide, 200 p.p.m. of the gas at high humidity was passed for 2 hours through a filter-paper loaded with various amounts of smoke collected from the air; no additional sulphuric acid was detected on the filter-papers, and thus sulphur dioxide can be assumed not to interfere significantly with the method. INTERFERENCE BY BASIC GASES- When particulate acid can be detected in town air, small amounts of free basic gases (ammonia and amines) can be found also.The co-existence of these two pollutants can be explained by the acidic particles being covered by carbonaceous, tarry or other solid material that hinders neutralisation with ammonia. In order to find out whether ammonia neutralises the acid during sampling, it was removed before the acid was collected. This was done by im- pinging the air approximately 2 cm above the surface of the concentrated sulphuric acid, a flow rate of 20 litres per minute being used. Preliminary experiments showed that ammonia gas mixtures of between 0.2 and 10 p.p.m. in air are absorbed with efficiencies of between 70 and 95 per cent., and that, when a prepared mist of sulphuric acid (2-5 mg per cu. metre, mass median diameter 0.50 p), was used, losses in the impinger did not exceed 6 per cent.Acidic particles of this size are found in the polluted air of London during fog; at other times the acid particles are smaller and the loss by impingement would be even less than that found in these experiments (there are also larger acidic particles, but these represent only a small fraction of those found in the polluted air of London). Several samples of acid were collected on filter-papers after ammonia had been removed in this way. These filter-papers were titrated and the results compared with those from samples collected without prior removal of ammonia. Sixteen pairs of samples were collected, each for 8 hours, in the City of London. Comparison of individual results showed in some instances small differences, but the average of the sixteen samples was 3.96 pg per cu.metre of acid, after the removal of ammonia, compared with 3.67 pg per cu. metre of acid for normal collection. This small difference (7.5 per cent.) between the results indicates that there is not enough ammonia present in the air of the City of London to invalidate this method of collecting the sulphuric acid.366 COMhIINS: DETERMINATION OF PARTICULATE ACID IN TOWN AIR [Andyd, VOl. 88 INTERFERENCE BY OTHER PARTICULATE ACIDS- Particulate acids other than sulphuric may be present in town air. These are hydro- chloric, nitric, phosphoric, sulphurous and nitrous acids; these acids may be wholly or partly caught on a collection filter-paper. Sulphuric acid can be efficiently filtered from air.4 Only extremely small amounts of nitrate, phosphate, sulphite and nitrite can be detected in samples collected on filter-paper, and the concentrations of the acids corresponding to these anions must therefore be extremely small.Solids collected from the air of the City of London contained from 0.2 to 2.4 mg of hydrogen ion per g (measured by titration). The chloride content varied between 15 and 150 mg per g, and if this chloride were all hydrochloric acid it would correspond to between 0.4 and 4.2 mg of hydrogen ion per g of solids, so that all the indicated acidity could be due to hydrochloric acid. However, there was no correlation between chloride and acidity in fifty samples collected during two prolonged periods of high pollution, whereas sulphate (present in concentrations between 40 and 200 mg per g of solids) and acidity were highly correlated.Sulphate was always present in amounts greater than could be accounted for by sulphuric acid alone. These findings suggest that the predominant acid present in air is sulphuric acid. INTEKFEREXCE BE’ PARTICULATE BASES- Organic bases are produced when coal is distilled, and thus thejr would be expected to be present in town air. The aliphatic bases and some aromatic bases are readily volatile at ordinary temperatures, but some of the less volatile aromatic bases may be expected to be present in particulate pollution. The latter bases are extremely weak and will not interfere with the titration of sulphuric acid if the pH is carefully chosen. Titration of known mixtures of a 10-fold excess of the aromatic base, aniline, in sulphuric acid, when an extraction solution of low initial pH was used that was titrated back to this pH after the mixture had been added, gave a low result for the acid present; for pH values less than 5-4 a negative amount of acid was indicated.For extraction solutions at pH 7, the true amount of acid was indicated when titrated back to this pH, and therefore such a procedure was chosen for titration of the acid collected from air. For procedures in which solutions of pH >7 were used, spuriously high amounts of acid were indicated. Samples of collected air solids behaved in a similar way to the aniline - sulphuric acid mixture. Soluble basic particles, such as lime or other metallic oxides or hydroxides, would, if present, interfere with the determination of acid by the titration of filter-paper samples.To find out if such bases are present, the acid in the samples can be neutralised with ammonia gas, and the unaffected bases, if present, determined by titration. This procedure was applied to collected air solids, and the samples were neutralised with ammonia over a period of 2 minutes, after which they were left in the laboratory for 2 hours before being titrated. Samples collected in London were neutralised by exposure to ammonia for 2 minutes and, after being left in laboratory air for 2 hours, were placed in water a t pH 7 ; they were never alkaline but were neutral or slightly acid. This indicated that only negligible amounts of soluble bases were present in the samples.Insoluble bases, such as calcium carbonate, may also be present; their presence can be detected by titrating with sodium tetraborate the “ammoniated” sample after a known excess of acid has been added. Results of these experiments have shown that many samples of solids collected from the air in London contain appreciable amounts of insoluble bases. In order to overcome the interference by insoluble bases, an amount of 0.01 N sodium tetraborate greater than the equivalent amount of acid (determined first by titrating a portion of the sample at pH 7) is added to 1 to 2 mi of water at pH 7, in which another portion of the sample is immersed; the solution is then titrated with 0.01 N sulphuric acid. This titration procedure allows the sodium tetraborate to neutralise the acid before the insoluble base has a chance to do so.It has been found that the results of the determinations of acid by this method are 10 per cent. higher at times of high pollution and up to 30 per cent. higher at times of low pollution than those obtained by direct titration. Although the method described above has been found to be suitable for determining acid in town air, two other methods have been considered. In one, the total particulate sulphate is taken to be an indication of the total particulate acid. This “sulphate index” has, however, proved unreliable for use in the City of London, since the acid content has been shown to vary from 20 to 80 per cent. of the amount of sulphate present. In the otherMay, 19631 COMMINS: DETERMINATION OF PARTICULATE ACID IN TOWN AIR 367 method, the acid is neutralised by adding excess of ammonia to the air before the air solids are collected on the filter-paper.The amount of ammonium ion present on the filter-papers was determined with Nessler’s reagent 2 hours later, after which time the ammonia not used for neutralisation had come off the filters. The ammonium ion content of an untreated sample of air solids was also measured and the amount of particulate acid calculated from the difference between the two results, it being assumed that all the acid had been converted to ammonium sulphate. This method takes longer than the titration method and the results are not as reproducible, but it has the merit that reactions on the filter-paper between the acid and other material present are minimised.RE su LTS RANGE OF CONCEKTRATION OF PARTICULATE ACID IN TOWN AIR- Con- centrations of particulate acid are especially high at times of fog and have reached levels of 678 pg (calculated as sulphuric acid) per cu. metre of air in the City of London. Typical winter daily concentrations are 18 pg per cu. metre of air, compared with 7 pg per cu. metre for summer in the City. The sulphuric acid content of the air in the City of London can be up to 10 per cent. of the total sulphur. The concentrations of particulate acid correspond to those of other pollutants. CONCLUSIONS The procedure developed for the measurement of particulate acid was suitable for its determination in urban air. Interference by other pollutants can be avoided by the use of a back titration technique. The particulate acid appears to be mainly sulphuric acid. I thank Dr. P. J. Lawther, Director of the Medical Research Council’s Air Pollution Research Unit, for his encouragement and help and Mr. R. E. Waller, Mr. T. Nash and Dr. J. McK. Ellison, also of the Unit, for helpful suggestions. I also thank Mr. A. Brooke, Mr. L. Hampton and Mr. D. Holland for technical assistance. REFERENCES 1. 2. 3. 4. 5 . Ellis, B. A., The Investigation of Atmospheric Pollution 17th Report, H.M. Stationery Office, 1931, Goodeve, C. F., Trans. Faraday SOC., 1936, 32, 1218. Coste, J. H., and Courtier, G. B., Ibid., 1936, 32, 1198. Mader, P. P., Hamming, W. J., and Bellin, A., Anal. Chern., 1950, 22, 1181. Waller, R. E., J . Roy. Met. SOC., in the press. p. 38. Received -November 7th, 1962

ISSN:0003-2654    

DOI:10.1039/AN9638800364

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

368 MIDDLETON : IODIMETRIC DETERMINATION OF [Analyst, Vol. 88 Iodimetric Determination of Milligram Amounts of Rubber Hydrocarbon BY K. R. MIDDLETON (Rubber Research Institute of Malaya, P.O. Box 150, Kuala Lumpur, Malaya) An iodimetric method is described for determining rubber hydrocarbon ; it is based on the bromination of the rubber molecule, and is sensitive to 2 mg of rubber dissolved in benzene. By comparing it with a standard procedure, it has been shown that the proposed method will determine accurately the rubber hydrocarbon content of field latex. The precision with which solutions of pure rubber in benzene can be determined by the method corresponds to a coefficient of variation of about 0.5 per cent., and rubber hydrocarbon in latex can be determined with a precision of about 1-5 per cent.THE chemical determination of rubber hydrocarbon may be based either on its property of forming a stable tetrabromide, as in early volunietric methods1s2 and in more recent gravi- metric rneth0ds,3~~~~ or on its ability to produce titratable volatile acids on oxidation with chromic acid.6 Volumetric methods are rapid and sensitive, but, although it has been claimed7 that rubber hydrocarbon can be satisfactorily determined by bromination, such procedures have not been found generally satisfactory. Their unsatisfactory nature may have been caused by faulty analytical techniques, and in the work described here an improved analytical procedure has been used for determining rubber hydrocarbon, after bromination of the rubber molecule under carefully controlled conditions.Bromination methods assume that the rubber hydrocarbon tetrabromide is formed by the addition of bromine at double bonds, as summarised in the equation- (‘lOH16) n + 2nBrZ ’= ( ‘ 1 1 3 ~ 1 6 ~ ~ 4 ) n Attempts have been made to allow for any extra bromine taken up through substitution by applying the McIlhiney correction,l s2 but according to Bloomfields the simultaneous absorption of halogen by cyclisation makes this impracticable. Substitution can, however, be suppressed by using a polar reagent; for example, bromine in glacial acetic acid, as in the work of Kemp and M~eller.~ For volumetric methods involving determination of the excess of bromine remaining after bromination, it is essential that a quantitative addition of the halogen should be made initially.Preliminary work had shown that such addition is extremely difficult when, as in the methods referred to above,1*2 solutions of bromine in a volatile solvent, such as carbon tetrachloride, are used. Solutions of this kind quickly lose bromine on exposure to the air; this is also true for solutions of bromine in acetic acid. Quantitative introduction of bromine can be readily made, however, by using bromide - bromate mixtures,lo and a polar reagent of this type has been used in the method of determining rubber hydrocarbon described below. The proposed method is designed for rubber that is completely soluble in benzene, since Willits, Swain and Ogg3 have shown by a gravimetric procedure that such a method can be applied to the determination of rubber in plant tissue.This application, which involves problems of extraction and of interference by other substances, is not discussed in this paper, but it is intended to show in a later publication how the proposed method can be used for determining rubber in plants. EXPERIMENTAL Before its determination rubber may be dissolved in carbon tetrachloride,l,2 chloroform’ or ben~ene.~ Benzene has been found most suitable for extracting rubber from plant tissue11 and, since one object of this paper is to describe a method also applicable to the analysis of plant material, the use of solvents other than benzene has not been studied. BROMINATION OF SOLUTIONS OF RUBBER IN BENZENE- Preliminary work had shown that both commercial and analytical-reagent grades of benzene absorbed appreciable amounts of bromine; further, when the same sample of benzene was repeatedly brominated, the amount of bromine absorbed each time rapidly decreasedMay, 19631 MILLIGRAM AMOUNTS OF RUBBER HYDROCARBON 369 with successive brominations.Purification of benzene by distillation alone did not reduce the amount of bromine absorbed, but washing with concentrated sulphuric acid produced a large decrease. These results suggested that much of the bromine was absorbed by an impurity such as thiophen, which would be removed by sulphuric acid but not easily by distillation, as it boils a t about the same temperature as benzene. The amount of bromine absorbed by rubber in solution must be obtained by subtracting the amount absorbed by the solvent from the total amount taken up by the solution, and for accurate work, therefore, purified benzene should be used, In Fig.1 values obtained by subtraction in this way show the rate at which bromine is absorbed by rubber dissolved in purified benzene; the corresponding absorption of bromine by the solvent is also shown. 20 1 Time of bromination, minutes Fig. 1. Effect of time on the bromination of benzene and rubber hydrocarbon: curve -4, purified rubber; curve B, purified benzene The effect of external conditions on the absorption of bromine was also investigated; rubber dissolved in purified benzene was brominated for 100 minutes, in clear bottles in both subdued and bright light and also in opaque bottles in a dark cupboard at various temperatures between 6" and 28" C.The results are shown in Table I, and indicate that the effect of light on the bromination of benzene is sufficiently pronounced to make it essential that, in the proposed procedure, bromination is carried out in the dark. The results also show that the effect of temperature on the bromination of both benzene and rubber in the dark is small compared with its effect in subdued or bright light. TABLE I EFFECT OF LIGHT AND TEMPERATURE ON THE BROMINATION OF BENZENE AND RUBBER The results are expressed as milligrams of bromine absorbed by 10 ml of purified benzene and by 8-92 mg of purified rubber Bromine absorbed f A 7 In the dark by- In subdued light by- In bright light by- Temperature, f-'--, & & "C benzene rubber benzene rubber benzene rubber 20 0.54 22.4 17.6 23.9 27 0.74 23.9 32.8 14.1 72.6 1.1 - - - - 7 0.32 21.5 - - METHOD REAGENTS- The reagents should be prepared from pure chemicals and distilled water.Sodium molybdate solution, 0.1 per cent. w/v in 10 per cent. v / v hydyochloric acid and 10 per cent. v / v acetic acid.370 MIDDLETON : IOUIMETRIC DETERMINA4TIOS OF (Analyst, Vol. 88 Potassium bromate solution, 0.55 $er cent. ZJ/V in 10 per ceizt. W / V potassium bromide solution. Sodium borate solution, 2.6 per cent. w/v, nqueous. Sodium thiosulphate solution, 2.5 $er cent. wlv, aqueous. Sodium thiosulphate solution, 0.04 N, aqueous. Iodine solution, 0.01 N in 4 per cent. w/v potassium iodide solution. Benzene-Purify by shaking with concentrated sulphuric acid and washing four times Filter the benzene, and then distil at 80" C; discard the first and last 50 ml of with water.distillate from 2 litres. PROCEDURE- Put a 25-ml portion of a benzene solution containing 5 to 10 mg of rubber hydrocarbon into an opaque stoppered bottle, and add 5 ml of sodium molybdate solution and then 5 ml exactly of potassium bromate solution. Replace the stopper tightly, mix the aqueous and benzene phases thoroughly, and place the bottle in a dark cupboard. After 100 minutes have elapsed record the temperature of the cupboard, remove the bottle, and quickly add 2 g of potassium iodide to the contents. Replace the stopper tightly, shake the solution thoroughly, and after 5 minutes quickly add 100ml of sodium borate solution. (A 100-ml calibrated flask with a spout permits rapid addition of sodium borate to be made; it is essential that this flask and all glass apparatus used in the bromination should be free from grease.) Again shake the solution thoroughly, and add 25 ml of sodium thiosulphate solution with continuous swirling.After 5 minutes, filter about 20 ml of the solution through a Whatman Yo. 1 filter-paper (previously moistened with distilled water to ensure that only the aqueous phase passes through), and discard. Filter the remainder of the aqueous phase into a clean dry flask, and titrate a 50-ml portion with the standard iodine solution and starch as indicator. Carry out a blank determination on 25ml of benzene only by the same procedure. The volume of standard iodine solution corresponding to the bromine absorbed by the hydrocarbon is obtained by multiplying the difference between the two titres by the total volume of the aqueous phase (135 ml) and dividing by the volume of the portion taken (50 ml).The amount of rubber present can then be calculated by multiplying this result by a factor, corrected for temperature as described below. Fig. 2. Variation with temperature of an empirical factor for calculating rubber hydrocarbon CALIBRATION OF THE METHOD- Fig. 1 indicates that there is a rapid initial absorption of bromine by rubber hydrocarbon, caused mainly by addition of the halogen at double bonds; subsequently there is a much slower absorption that may be- caused partly by substitution of hydrogen. If this is so, bromination will not always produce the tetrabromide quantitatively, but it can be experi- mentally shown with considerable precision that at a given temperature the amount ofMay, 19631 MILLIGR-4M AMOUNTS OF RUBBER HYDROCARBOX 37 I bromine absorbed per milligram of rubber is nearly constant over the range 2.5 to 12-5 mg; an empirical factor can therefore be used to relate the weight of rubber to the amount of bromine absorbed. I t was clear from the results shown in Table I that the factor would vary with temperature, and the nature of this variation is shown in Fig.2 ; these results were obtained by brominating in accordance with the proposed procedure 8mg of purified rubber in 25 ml of purified benzene. A highly significant linear regression of an empirical factor (expressed as mg of rubber per ml of 0.01 N iodine) on temperature is shown, with a negative slope corresponding to the equation- Factor at to C = 0.3339 - 0-000589 (t - 25).-4 similar calibration, carried out with synthetic cis-polyisoprene as the standard substance, gave a slightly different factor with a more pronounced temperature gradient corresponding to the equation- Factor at to C = 0-3345 - 0.00126 (t - 25). COMPARISON \VITH A STANDARD METHOD FOR ANALYSING LATEX The dry rubber content of field latex, which includes rubber hydrocarbon together with small amounts of other materials,12 was determined by a standard method,13 and rubber hydrocarbon was determined by the proposed method, after non-rubber substances capable of absorbing bromine had been removed by means of the pre-treatment described below. Weigh 0.15 to 0-20 g of latex into a 250-ml beaker, and spread by adding 1 ml of water and rotating.Evaporate to dryness on a steam-bath at 90" C, when an extremely thin translucent film should form on the bottom of the beaker. Extract three times with 100 ml of boiling ethanol, 15 minutes being taken for each extraction. After the final extract has been removed by decantation, heat on the steam-bath until free from ethanol. Add 150 ml of purified benzene, stir thoroughly at intervals, and, when all the rubber has dissolved, make up to 250ml in a calibrated flask. Determine the content of rubber hydrocarbon in a 25-ml portion by the procedure described above. The results of the comparison were plotted (see Fig. 3) and reveal a highly significant regression of rubber hydrocarbon on dry rubber content.Dry rubber content, % Fig. 3. Regression of rubber hydrocarbon in field latex upon dry rubber content DISCUSSION OF THE METHOD The amount of bromine absorbed, by both hydrocarbon and solvent, is equal to the difference between the amount added and the amount remaining a t the end of the reaction; an excess of potassium iodide converts the latter into an equivalent amount of iodine, which can then be titrated with thiosulphate.372 MIDDLETON : IODIMETRIC DETERMINATION OF [Analyst, Vol. 88 The presence of three phases (aqueous, benzene and rubber bromide) had made the direct titration of liberated iodine difficult, the more so when bromination was carried out in opaque bottles. Moreover, as pointed out by Fisher, Gray and Merling,2 traces of excess of bromine, occluded in the precipitated bromide, may not be released during the titration.These difficulties are avoided in the proposed method by adding a measured excess of thiosulphate and by waiting until its reaction with the halogen is complete; the aqueous phase is then filtered off, a portion of it is taken and the excess of thiosulphate is titrated with standard iodine solution. Thiosulphate is however unstable in contact with the amount of acid needed to release bromine from bromide - bromate mixtures, and for accurate titrations a definite pH is needed, depending on the concentrations of iodine and thiosulphate used.lO In the proposed procedure the acid is partly neutralised with sodium borate before the addition of thiosulphate, and a borate - acetate buffer giving a final pH of 5.5 is thus formed.Another difficulty had arisen when a strong acid only was used to liberate bromine from bromide - bromate mixtures; this acid (hydrochloric) produced an excessive amount of heat when neutralised by sodium borate. The problem was eventually solved by replacing part of the hydrochloric acid by acetic acid, which liberates less heat on neutralisation, and by adding sodium molybdate, which strongly catalyses the release of bromine under such conditions.1° In Fig. 1, the line x - x marks an absorption of 17 mg of bromine by 7.24 mg of rubber; this amount corresponds to a quantitative formation of rubber hydrocarbon tetrabromide, which contains 70.13 per cent. of bromine, and the minimum brominstion time required to form it appears to be about 70 minutes.The rate of absorption of bromine seems, however, to fall off appreciably after 100 minutes, and since this time has been used by other workers5 it has been adopted as the bromination time in the proposed procedure. ACCURACY AND PRECISION OF THE METHOD- The calibrations recorded above show that similar results are obtained when purified rubber and cis-polyisoprene are used, although the effect of temperature on bromination is not exactly the same for both substances. I t is, however, accepted that there are definite differences in structure between cis-polyisoprene and natural rubber.14 Moreover, recent work15 has suggested the presence of aldehyde and other abnormal groups in the natural rubber molecule; both these variables might be expected to cause a difference in bromination between the two materials, when the procedure described above is employed.The cis-polyisoprene is considered to have a rubber hydrocarbon content of between 99-5 and 100 per cent.; the purified natural rubber, from which inorganic matter, proteins and fatty materials had been removed by treatment with an aqueous detergent and alcohol, should be of similar purity. The fact that calibrations made by using the two standards have given similar results can therefore be taken as an indication of the satisfactory accuracy of the method. The accuracy of the method can also be judged by comparing it with a standard pro- cedurel3 for determining the dry rubber content of field latex.The results of the comparison are recorded in Fig. 3, in which mean rubber hydrocarbon values (obtained from duplicate brominations on each of two sub-samples of latex) are plotted against the means of two deter- minations of dry rubber content on the same samples of latex. The linear correlation between rubber hydrocarbon (R.H.C.) and dry rubber content (D.R.C.) is highly significant (correlation coefficient + 0-989), and the corresponding regression equation is- R.H.C. = D.R.C. x 1.0134 - 0.580 (standard error (standard error f. 0.0268) 1.013) The deviations of the slope (1.0134) and the intercept (-0.580) from unity and zero, respec- tively, are not statistically significant, and the least squares regression differs only insig- nificantly from the relation R.H.C.= D.R.C.; this can be readily shown in terms of the total variation among the 34 samples-the least squares regression accounts for 97-81 per cent. of the variation, whereas the alternative relation (R.H.C. = D.R.C.) accounts for 97-78 per cent. This implies, but does not establish, that in this comparison of methods R.H.C. is equivalent to D.R.C.; but it should be noted that the regression equation given above has been worked out for field latex only-when other lattices are involved, for example, skim orMay, 19631 MILLIGRAM AMOUNTS OF RUBBER HYDROCARBON 373 concentrate, it may be necessary to re-determine the equation, but the same method would seem to be applicable. Table I1 summarises the statistical examination of the rubber hydrocarbon results obtained in the comparison of methods.The components of variance show that considerably more error is associated with sub-sampling and pre-treatment (which are confounded) than with bromination and titration (which are also confounded). By combining components for these sources of variation, the standard error of a single determination of rubber hydro- carbon, on any given sample of latex, can be estimated as 20.5712, which corresponds to a coefficient of variation of 1-53 per cent. The coefficient of variation associated with duplicate brominations is, however, 0.48 per cent. and this figure agrees well with a value of 0.35 per cent. computed for duplicate determinations, the means of which are plotted in Fig. 2. TABLE I1 STATISTICAL ANALYSIS OF RUBBER HYDROCARBON DETERMINATIONS ON 34 SAMPLES O F LA4TEX Degrees of Component of Source of variation freedom Mean square variance 140*7858** * u22 = 35.0412 Between samples of latex .. . . . . . . . . 33 Between sub-samples within samples of latex . . . . 34 0*6210*** uI2 = 0.2948 uo2 = 0.0315 Between duplicate brominations on sub-samples of latex 68 0.03 15 Total . . . . . . . . . . . . 135 Mean rubber hydrocarbon content = 37.296 per cent. by weight. Standard error of a single determination on a given sub-sample = &oo = -t 0.1775; coefficient Standard error of a single determination on a given sample = 2 duo2 + u12 = 2 0.5712; - - of variation = 0-48 per cent. coefficient of variation = 1-53 per cent. *** Significant a t the 0.1 per cent. level. CONCLUSIONS The proposed method shows that milligram amounts of rubber hydrocarbon soluble in benzene can be rapidly determined by iodimetric titrations, after preliminary bromination of the rubber molecule.Various experimental conditions necessary to attain satisfactory accuracy and precision are specified. They include exclusion of light during a definite bromin- ation period, correction for different brominating temperatures, the use of an inorganic brominating reagent in order to ensure quantitative addition of bromine, and careful control of the procedure used for the iodimetric determination. The determination of rubber hydro- carbon by the proposed method is also shown to be closely correlated with the determination, by a standard method, of the dry rubber content of field latex.I thank the Director of the Rubber Research Institute of Malaya for permission to publish this paper. I also thank Mr. Chin Pong Tow for help with the experimental work, Mr. B. C. Sekhar for many helpful discussions and Messrs. D. R. Westgarth and G. C. Iyer for statistical aid. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. REFERENCES Lewis, W. K., and McAdams, W. H., Ind. Eng. Chew., 1920, 12, 673. Fisher, H. L., Gray, H., and Merling, R., Ibid., 1921, 13, 1031. Willits, C. O., Swain, M. L., and Ogg, C. L., I n d . Eng. Chem., Anal. Ed., 1946, 18, 439. Baker, T. I., Jayko, L. G., Stubblefield, R. D., and Anderson, R. F., Anal. Biochem., 1961, 2, 287. Meeks, J. W., Crook, R. V., Pardo, C. E., and Clark, F. E., Anal. Chern., 1953, 25, 1535. Burger, V. L., Donaldson, W. E., Baty, J. A., Rubb. Chem. & Tech., 1943, 16, 660. Bloomfield, G. F., J . Chern. SOC., 1944, 114. -, J . SOC. Chem. Ind., 1945, 64, 274. Kemp, A. R., and Mueller, G. S., Ind. Eng. Chem., Anal. Ed., 1934, 6, 52. Kolthoff, I . M., and Sandell, E. B., “Textbook of Quantitative Inorganic Analysis,” Third Edition, The Macmillan Company, New York, 1952. Spence, D., and Caldwell, M. L., Ind. Eng. Chew., Anal. Ed., 1933, 5, 371. Gibbons, W. A., and Brass, P. D., “Properties of Latex,” in Davis, C. C., and Blake, J . T., Editors, “Chemistry and Technology of Rubber,” Reinhold Publishing Corporation, New York, 1937. “ASTM Standards 1961,” Part 11, American Society for Testing Materials, Philadelphia, p. 490. Stavely, F. W., and co-workers, I n d . Eng. Chern., 1956, 48, 778. Sekhar, B. C., “Abnormal Groups in Rubber and Microgel,” Paper presented a t the Fourth Rubber Received October 26th, 1962 Technology Conference, London, 1962.

ISSN:0003-2654    

DOI:10.1039/AN9638800368

出版商:RSC    

年代:1963

数据来源: RSC

摘要:

374 SCHOLES AND WATERMAN : DETERMINATION OF [Ltnalyst, 1’01. 88 Determination of Arsenic in Copper and Copper-base Alloys BY I. R. SCHOLES , ~ N D W. R. WATERMAN (Iwtpevial MPtal~Industvies (Kynoch) Ltd., P.O. Box 2 1 G , Kynoch Works, Witton, Birmingham 6) Existing procedures for determining arsenic in copper and its alloys have known limitations and disadvantages, especially when less than about 100 p.p.m. of arsenic are present and a 5-g sample is not available. A procedure has been developed, involving not more than 1 g of sample, and successfully applied to the analysis of typical samples, including copper- base alloys containing up to 0.2 per cent. of arsenic. Limited tests have shown the method to have a potential application in ferrous analysis. The sample is dissolved in a hydrochloric acid - hydrogen peroxide mixture ; quinquivalent arsenic is reduced with hypophosphorous acid, and an empirical extraction of the arsenious chloride is made into chloroform.The recovered arsenic is oxidised to the quinquivalent state and then determined absorptiometrically after reduction of arsenomolybdate to molybdenum blue. The recommended procedure is suitable for determining arsenic down to a t least 5 p.p.m. in copper and 20 p.p.m. in brass, bronze or cupro-nickel; it is not subject to interference from alloying elements and impurities nor- mally present in these materials. A single determination takes about 2 hours, but a t least 8 determinations can be completed by one analyst in a normal working day. SEVERAL methods are available for determining arsenic in non-ferrous materials, but none is entirely suitable for amounts of less than 100 p.p.m.when the sample weight is restricted t o 1 g or less. Although such amounts of arsenic would normally be determined spectro- ,graphically, there is still a need for an accurate and sensitive method for analysing standard samples. Two procedures are given in B.S. 1800,l one based on a preliminary distillation of arsenious chloride, the other on an initial precipitation, with hypophosphorous acid, of elemental arsenic, together with selenium and tellurium, and then by separation of interfering elements; both procedures are completed by titration with a standard iodine solution. These two methods have known limitations and disadvantages; e.g., in both procedures, when the amount of arsenic present is small, the volume of standard iodine solution is also small, and a minimum sample weight of 5 g is therefore necessary when the arsenic content is less than about 100 p.p.m.Other methods are available for determining arsenic in non-ferrous rnaterial~,~.374,5,6 but phosphorus, selenium, tellurium and silicon, which are present in some grades of copper and its alloys, interfere in one or other of these methods. The separation of arsenic by precipitation with hypophosphorous acid is only 90 to 95 per cent. complete7; selenium and tellurium are also precipitated. This separation has been used by CaseS in the preliminary stages of a method for determining arsenic at levels above 0.1 mg in copper-base alloys before determining the arsenic as molybdenum blue.Experiments in these laboratories have shown that, when the amount of arsenic separated in this way is less than 0.1 mg, the efficiency of separation is variable-frequently less than 90 per cent .-and that selenium suppresses development of the molybdenum-blue colour. Variable recoveries of arsenic after precipitation with hypophosphorous acid seem to be associated with conditions for precipitation and subsequent washing of the elemental arsenic. Opinions on optimum conditions for these operations are conflicting, and the authors’ work has failed to improve the reproducibility of the procedure for determining arsenic below 100 p.p.m. Tervalent arsenic can be extracted from a hydrochloric acid solution into certain organic solvents; e.g., from 11 M hydrochloric acid, recoveries of 94 per cent.with benzene9 and about 75 per cent. with carbon tetrachloridelo have been reported. These observations were made the basis of subsequent experimental work designed to provide a satisfactory methodMay, 19631 ARSENIC IS COPPER AND COPPER-BASE ALLOYS 375 for determining small amounts of arsenic when the weight of sample was restricted to about 1 g. It was proposed to complete the determination absorptiometrically by the method described by Case8 EXPERIMENTAL ABSORPTIOMETKIC DETERMINATION OF ARSENIC- A calibration graph was prepared, without involving an extraction, by using the colour development conditions recommended by Case.8 A standard solution of tervalent arsenic was prepared by dissolving arsenious oxide in sodium hydroxide solution.Volumes of this solution, containing from 0.01 to 0.1 mg of arsenic, were placed in separate 50-ml calibrated flasks. To the contents of each flask were added 5 drops of 0.1 N iodine, to oxidise tervalent arsenic, 5.0 ml of a 1 per cent. w/v solution of ammonium molybdate in dilute sulphuric acid (1 + 6) and 2-0ml of 0.15 per cent. w/v hydrazine sulphate solution. Each flask was immersed in a boiling-water bath for 10 minutes, cooled, and diluted to the mark; the optical densities were then measured at 8400 in 2-cm cells. The relation between optical density and concentration of arsenic was linear, 0.05 mg of arsenic corresponding to an optical density of 0-69. FORMATION AND EXTKACTION OF TEKVALENT ARSESIC- Tests in which tervalent arsenic was extracted from 11 M hydrochloric acid into benzene, cliloroform or carbon tetrachloride showed that the efficiency of extraction decreased in this.order and, although benzene was over 20 per cent. more efficient than chloroform, separation of the organic phase was less defined than when chloroform was used. From 50 mi of 11 M hydrochloric acid containing 0.05 mg of tervalent arsenic, 71 per cent. of the arsenic was. extracted by 25 ml of chloroform, and this amount decreased with decrease in the concen- tration of acid. Based on these observations, conditions for extracting arsenious chloride were stan- dardised, and a series of standards was prepared and examined. Volumes of a standard solution of tervalent arsenic, containing 0.01 to 0.1 mg of arsenic were placed in separate 100-ml separating funnels, each containing 50 ml of concentrated hydrochloric acid.To the contents of each funnel were then added 25ml of chloroform, the mixture was shaken vigorously for 3 minutes, and the aqueous layer was discarded. The chloroform was then shaken for 1 minute with 20ml of water, and discarded. The aqueous layer was run into- a 50-ml calibrated flask, 5 drops of 0.1 N iodine were added, and the molybdenum-blue complex was developed as described earlier, Recoveries were plotted, and the resulting graph was linear (0.05 mg of arsenic corresponding to an optical density of 0-48), indicating that extraction of arsenious chloride into chloroform could provide a suitable method for deter- mining arsenic.Because the sample must be dissolved under oxidising conditions, to prevent loss of arsenic, arsenic is maintained in the quinquivalent state during solution of the sample, and, as such, less than 5 per cent. is extracted into chloroform. Attempts to reduce quinquivalent arsenic to the tervalent state in solutions of cupric chloride in concentrated hj.drochloric acid with hydroxyammonium chloride or hydrazine hydrochloride were unsuccessful ; both reagents were unsuitable, and subsequent recoveries of arsenic were low. Improved, although variable, recoveries were obtained when stannous chloride was used as a reducing agent. At temperatures below about 50" C, quinquivalent arsenic in 6 M hydrochloric acid is. reduced by hypophosphorous acids1 to tervalent arsenic, and not, as might be expected, to elemental arsenic. It was also found that, when quinquivalent arsenic was reduced with hypophosphorous acid, provided copper was completely reduced to the cuprous state, nearly 70 per cent.of the arsenic present in a cupric chloride - 11 M hydrochloric acid solution was recovered by a single extraction into 25 ml of chloroform at 20" C. When this reduction procedure was applied to a sample of vacuum-cast copper, arsenic values, obtained by the molybdenum-blue method, were high and variable, but if the chloro- form extract was washed with 11 M hydrochloric acid before the arsenious chloride was extracted, which presumably had the effect of removing entrained phosphorus-containing- salts, the values were low (as expected} and consistent.376 SCHOLES AND WATERMAN: DETERMINATION OF [Analyst, VOl.88 A graph obtained under these conditions was linear, although of lower slope than the earlier graphs, 0.05 mg of arsenic corresponding to an optical density of 0.44. The values obtained agreed with the values calculated from the known distribution of tervalent arsenic between chloroform and hydrochloric acid, indicating that complete reduction of tervalent arsenic had been achieved. It was also found that equilibrium between the chloroform and the 11 M acid phase was established within 1 minute of shaking. To extend the range of application of the procedure to determining arsenic in excessof 100 p.p.m., the effect of extracting 0.06 mg of arsenic from solutions containing from 0.1 to 1 g of copper was examined.Results showed that the amount of tervalent arsenic extracted increased progressively with increase in copper concentration, but became constant when 0.4 g or more of copper was present (see Table I). This observation was not altogether surprising, because it is known that a relatively large amount of copper must be present in order to achieve quantitative reduction of quinquivalent arsenic with hypophosphorous acid. To make the calibration graph independent of sample weight, therefore, the amount of copper present should be greater than 0.4 g, and, in subsequent experiments, pure copper was added to the weighed sample, when necessary, so that the total weight of copper present was 1 g. TABLE I EFFECT O F COPPER ON EXTRACTION OF 60 P.P.m. OF ARSENIC g (2-cm cells ; 8400 A) g (2-cm cells ; 8400 k ) Copper present, Optical density Copper present, Optical density 0.1 0.2 0-3 0-4 0.445 0.480 0.540 0.558 0.5 0.7 0.8 1.0 0.556 0.558 0.558 0.562 EFFECT OF REAGENTS- The extraction of tervalent arsenic into chloroform is governed by a distribution law, and therefore the effect of altering the amounts of the various reagents had to be considered.The amounts of hydrochloric acid and chloroform for the first extraction were fixed at 60 and 25 ml, respectively; these volumes were convenient for manipulation purposes. A l-ml variation in the volume of the hydrochloric acid did not significantly affect the recovery of arsenic, and this reagent was added from a measuring cylinder. A similar variation in volume of chloroform was significant, and addition was made from a pipette.Salts entrained in the chloroform extract were reduced to an insignificant level by washing with 10 ml of concentrated hydrochloric acid, and, although the volume of water necessary to remove arsenic from the chloroform extract could be as low as 5 ml, 20 ml was used to dilute any residual hydrochloric acid in the separating funnel, and also to allow the aqueous extract to be conveniently washed into a 50-ml calibrated flask. The hydrochloric acid and water were both added from measuring cylinders. TABLE I1 RECOVERY OF ARSENIC FROM HIGH-CONDUCTIVITY COPPER Sample No. Element added Amount of element added, % Germanium 0.1 Selenium 0.1 Tellurium 1 - - V.C. A V.C. A I - C.C. - - L.V. 6 - - B. 19 Amount of arsenic added, p,p.m.60 60 60 50 Nil 5 Nil 5 Nil 5 Nil 5 Amount of arsenic found, p.p.m. 58 57 61 50.7, 49.3, 49.6, 49.8, 50.5, 50.6, 51.2, 50.1 4 7 4 8 7 14 60 65May, 1063j ARSENIC IN COPPER AND COPPER-BASE ALLOYS 377 The concentration of hypophosphorous acid was shown to be unimportant, provided However, to maintain Provided the acid ammonium molybdate and hydrazine sulphate solutions were freshly Because the molybdenum-blue reaction it was sufficient to reduce copper completely to the cuprous state. a constant acidity the volume of this reagent added was fixed at 3.0 ml. prepared, the calibration graph was reproducible. is dependent on pH, these reagents were added from a pipette. EFFECT OF OTHER ELEMENTS- Samples of vacuum-cast copper (1 g), to which had been added a standard solution equivalent to 60 p.p.m.of arsenic and solutions of germanium, selenium or tellurium, were examined by the recommended procedure. No interference was observed from the presence of 0.1 per cent. of either germanium or selenium. Selenium and tellurium were both pre- cipitated by hypophosphorous acid, but, whereas selenium accumulated on top of the chloro- form interface and remained in the separating funnel when the chloroform was removed, the presence of 1 per cent. of tellurium obscured the phase boundary and made a clear separa- tion of the phases difficult. This difficulty was overcome by filtering the reduced solution through a Whatman No. 542 filter-paper before extraction into chloroform (see Table 11). The information contained in Table I11 indicates that the alloying constituents and impurities present in these samples do not interfere in the proposed procedure.TABLE 111 h A L Y S I S OF MISCELLANEOUS SAMPLES Sample No. 7 . . .. . . . . . . No. 11 . . . . . . . . .. Brass (70/30) No, 15 . . . . . . . . .. I No. 1 7 . . . . .. . . . . No. 8 . . . . . . . . . . No. 9 . . . . . . . . . . Brass (86/15) No. 10 . . . . . . . . . . No. 21 . . . . .. . . . . No. 22 . . . . . . . . . . f . . .. . . . . . . . . . . . . . . . . I Everdur S185 (96 Cu/3 Si/l Mn) . . Arsenic de-oxidised copper, S186 . . Chrome copper S187 (99 Cu/0.5 Cr/0-3 Zn/0-2 Ni) Alumbro M5363 (78 Cu/20 Zn/2 Al) . . B.C.S. 153 Bronze A (85 Cu/lO Sn/2 Zn/2 Pb/0.25 P) B.C.S. 179 Manganese brass I3 (59 Cu/34 Zn/l Mn/l Fe/ B.C.S.207 Bronze C (86 Cu/lOSn/2:5 Zn/O.i Ni/0-5 Pb) B.C.S. 153/1 Bronze (85 Cu/5 Sn/5 Zn/4 Pb/0.5 P/0-5 Ni) B.C.S. 180/1 Cupro-nickel (67 Cu/31 Ni/0.8 Fe/0.8 Mn) . . 2 Sn/l.5 A1/2 Pb/l Ni) . . . . B.C.S. 239/1 Carbon steel . . .. .. .. .. Arsenic found by- proposed alternative procedure, procedure, p.p.m. p.p.m. 36, 36 39 21, 23 17 35,35 33 1860, 1870 1930 48, 46 45 71, 70 70 53, 53 49 30, 32 31 130, 129 140 100,100 90 3400, 3400 3500 59, 62 63 410 420 620 - I h \ 190 - 620 - 1380 - 120, 119, 118 - 370,360 - Certificate value, p.p.m. I 500 to 600" 200 to 400* 500 1400 50 to SO* 330 * These certificate values are not standardised. Comparisons are given to indicate that the values obtained by the proposed procedure are likely t o be correct and that the procedure is applicable t o these materials. APPLICATION OF THE PROCEDURE- Several samples of brass (85 per cent.of copper, 15 per cent. of zinc and 70 per cent. of copper, 30 per cent. of zinc) were examined by the proposed procedure. They were also analysed by a method in which arsenic was determined absorptiometrically as described in the proposed procedure, but after a preliminary distillation of arsenic; good agreement was obtained in all these tests (see Table 111). The precision of the proposed procedure was established by examining a 10-g sample of pure copper to which had been added, as a standard solution of arsenic, the equivalent of 50 p.p.rn. of arsenic, The sample was dissolved in a hydrochloric acid - hydrogen peroxide378 SCHOLES AND WATERMAN : DETERMINATION OF [AndJJSt, VOl.88 mixture, and arsenic was determined in eight aliquots each containing the equivalent of 1 g of copper. The standard deviation obtained was 0-6 p.p.m., and the maximum deviation was 0.9 p.p.m. (see Table 11). The procedure was also applied to British Chemical Standard samples of leaded tin-bronze, manganese-brass and cupro-nickel, and the arsenic values found were in agreement with those reported in the Certificates; most of the arsenic values are quoted in the Certificates over a relatively wide range. When the method was applied to copper-base alloys containing alloying amounts of silicon, aluminium or chromium, the arsenic values found were in good agreement with those obtained by alternative procedures. In the examination of chromium- bearing samples it was necessary to dissolve the sample with the aid of perchloric acid, to ensure complete solution of chromium. Limited tests on a sample of carbon steel to which 1 g of copper had been added indicated that the procedure could be extended to ferrous materials. These values are summarised in Table 111.METHOD REAGENTS- Standard arsenic solution-Dissolve 0.132 g of arsenious oxide, previously dried at 105" C, in 5 ml of warm 5 per cent. w/v sodium hydroxide solution. Dilute to 100 ml, add diluted sulphuric acid (1 + 1) until the solution is just acid to litmus paper, and then dilute to 1 litre. 1 ml = 0.02 mg of arsenic. Ammonium molybdate solution, 1 per cent. ul/z)-Add, slowly, 14 ml of Concentrated sulphuric acid to 60 ml of water, and then dissolve 1 g of ammonium molybdate in the warm solution. Dilute 50ml of this solution to 250ml.Cool, and dilute to 100ml. This reagent must be freshly prepared. PREPARATION OF CALIBRATION GRAPH- Place, separately, 1.0, 2-0, 3-0, 4.0 and 5.0 ml of the standard arsenic solution (1 ml = 0-02 mg of arsenic) in each of five 100-ml beakers containing 1.0 g of pure copper ; use a sixth beaker containing 1.Og of copper for a blank determination. Continue with each beaker as described below. Add 5 ml of concentrated hydrochloric acid, and then place in a cold-water bath. Add 3 ml of 100-volume hydrogen peroxide, allow the initial reaction to subside, and then add a further 7 ml of the hydrogen peroxide. When solution of the sample is complete, remove the beaker from the water bath, and allow the solution to simmer at the side of a hot-plate to decompose the excess of hydrogen peroxide ; finally, evaporate the solution to dryness.To the residue add 50 ml of concentrated hydrochloric acid, stir to dissolve soluble salts, adjust the temperature to 20" C, add 3.0 ml of 50 per cent. w/w hypophosphorous acid, and then set the solution aside for 5 minutes. Transfer the solution to a dry separating funnel, with the aid of 10 ml of concentrated hydrochloric acid, add 25.0 ml of chloroform, and then shake vigorously for 1 minute. Allow the two layers to separate, and run the lower (chloroform) layer into a dry separating funnel; discard the aqueous layer. Shake the chloro- form extracts with 10ml of concentrated hydrochloric acid for 30 seconds.Allow the two layers to separate, and run the lower (chloroform) layer into a dry separating funnel; discard the aqueous layer. Add 20ml of water, and shake vigorously for 1 minute; allow the two layers t o separate, discard the lower (chloroform) layer, and transfer the aqueous layer to a dry 50-ml calibrated flask with about 5 ml of water. Add the reagents listed below in the order stated; wash down the neck of the flask, and mix well after each addition- 5 drops of 0.1 N iodine solution; 5.0 ml of 1 per cent. w/v ammonium molybdate solution; 2.0 ml of freshly prepared 0.15 per cent. w/v hydrazine sulphate solution. Stand the flask in a boiling-water bath for 10 minutes, then cool to 20" C, and dilute Measure the optical density at 8400A in 2-cm cells. t o the mark.May, 19631 ARSENIC IN COPPER AND COPPER-BASE ALLOYS 379 PROCEDURE- paration of Calibration Graph” (see Note 3).pure copper. Dissolve 1 g of the sample (see Notes 1 and 2), and continue as described under “Pre- With each batch of samples, simultaneously determine a reagent blank value on 1 g of NOTES- For arsenic contents above this range, use a proportionally smaller weight of sample, and add sufficient pure copper to bring the weight of copper to 1 g. In the examination of alloys containing chromium, e g . , Kumium, dissolve the sample in 5 ml of perchloric acid, sp.gr. 1-54, and 1 ml of concentrated nitric acid, and then evaporate to dryness. Dissolve the residue in 50 ml of concentrated hydro- chloric acid, and continue as described under “Preparation of Calibration Graph.” In the examination of alloys containing tellurium, above about 0.1 per cent., redissolve the residue, after evaporation, in 30 ml of concentrated hydrochloric acid. Adjust the temperature to 20” C, add 3.0 ml of the hypophosphorous acid, and set aside for 5 minutes. Filter the solution through a Whatman No. 542 filter-paper into a dry separating funnel, and wash the filter-paper with three 10-ml portions of concentrated hydrochloric acid. Continue as described under “Preparation of Calibration Graph.” 1. Applicable to samples containing up to 100 p.p.m. of arsenic. 2. 3. CONCLUSIONS The proposed procedure is suitable for determining arsenic down to at least 5 p.p.m. in copper and 20 p.p.m. in copper-base alloys containing common alloying constituents. Selenium and tellurium up to at least 0-1 and 1 per cent., respectively, do not interfere. A single determination takes about 2 hours, but at least 8 determinations can be completed by one analyst in a normal working day; the precision of the method is within 1 p.p.m. at the 50 p.p.m. of arsenic level. We thank Mr. W. T. Elwell, Chief Analyst, Imperial Metal Industries (Kynoch) Limited, for helpful suggestions and guidance in the preparation of this paper. 1. 2. 3. 4. 6. 7 . 8. 9. 10. 11. D. REFERENCES “Methods for the Analysis of Raw Copper,” British Standard 1800 : Parts 2 and 8 : 1951. “A.S.T.M. Methods for Chemical Analysis of Metals,” American Society for Testing Materials, Gullstrom, D. K., and Mellon, M. G., Anal. Chem., 1953, 25, 1809. Steel, M. C., and England, L. J., Analyst, 1957, 82, 595. Boltz, D. F., and Mellon, M. G., Anal. Chem., 1947, 19, 873. Sandell, E. B., “Colorimetric Determination of Traces of Metals,” Third Edition, Interscience Smales, A. A., and Pate, B. D., Anal. Chem., 1952, 24, 717. Case, D. P., Ibid., 1948, 20, 902. Green, M., and Kafalas, J. A., J . Chem. Phys., 1954, 22, 760. Fischer, W., Hurre, W., Freese, W., and Hackstein, K. G., Angew. Chem., 1954, 66, 165. Challis, H. J. G., Analyst, 1941, 66, 58. Philadelphia, 1956, p. 487. Publishers Inc., New York, 1959, p. 282. Received Novenzber 2nd, 1962

ISSN:0003-2654    

DOI:10.1039/AN9638800374

出版商:RSC    

年代:1963

数据来源: RSC