摘要:

Proceedings of the Society for Analytical Chemistry Analytical Division Chemical Society CONTENTS Reports of Meetings . . . . Electroanalytical Group . . Recent Advances in General Analytical Chemistry . . First Theophilus Redwood Lecture . . . . . . Summaries of Papers “Recent Trends in Analytical Chemistry” . . .. Short Courses . . . . .. Notices .. .. .. .. SAC/AD Tie .. .. .. Errata . . . . .. .. Publications Received . . 23 I 233 234 238 242 255 255 257 256 257 Proc. SOC. Analyt. Chern. Vol. 9 No. I I Pages 231-258 Forthcoming Meetings Back Cover November 1972 ’AYCAL Vol. 9 No. I I November 1972 PROCEEDINGS THE SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY OF Hon. Secretory W. H. C. Shaw Officers of The Society for Analytical Chemistry and the Analytical Division of The Chemical Society President C.Whailcy Hon. Treosurer Hon. Assistont Secretories G. W. C. Milne; D. I. Coomber O.B.E.; D. W. Wilson Secretary Miss P. E. Hutchiwon 9/10 SAVILE ROW LONDON WIX IAF Tclephonc 01-734 9864 Editor J . B. A t t r i l l Assistant Editor P. C. Weston Proceedings is published by The Society for Analytical Chemistry and distributed to all members of the Analytical Division and t o subscribers with The Analyst; subscriptions cannot be accepted for Proceedings alone. Single copies can be obtained direct from The Chemical Society Publications Sales Office Blackhorse Road Letchworth Herts. SG6 I HN (NOT through Trade Agents) price 25p. post free. Remittances MUST accompany orders. 0 The Society for Analytical Chemistry BURNS NIGHT 1973 FILM AND SLIDE SHOW (with appropriate refreshments) THE SAC/Analytical Division will hold an informal Social Evening at Imperial College London S.W.7 on January 25th 1973.The main entertainment of the evening is intended to be the showing of films and slides taken of people events and “happenings” at various conferences and meetings (at home and abroad). In view of the interesting material available from earlier years it has been decided not to limit the period of coverage to post-1962 as an- nounced in the October issue of Proceedings (p. 227). There must be many members (or non-members) who have suitable material in their possession possibly some that has not been looked a t for years. For this evening to be a success we should like to invite their co-operation and to let us know if they would be willing to participate. When a general assessment of the available material has been made we can then decide on the best method of presentation. (1) number of slides and size; (2) type and length of film; (3) date and place of conference or meeting at which they were taken. Information should be sent as soon as possible to Mrs. D. Butterworth Division of Chemical Standards National Physical Laboratory Teddington Middlesex. Please send details of-

ISSN:0037-9697    

DOI:10.1039/SA97209FX043

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Forthcoming Meetings-continued from back cover November-continued Vt‘eclnesday 29th JOINT PHARMACEUTICAL ANALYSIS GROUP Open Forum on “Questions and Panel Members C. A. Johnson L. E. Coles L. M . -Atherden Jf. Ogden and Pharmacy Lecture Theatre New Building University of Wales Institute of CARDIFF Answers in Pharmaceutical Analysis.” J . Chissell. Science and Technology Cathays Park Cardiff; 2.30 p.m. December Friday 1st LONDON Tuesday 5th TEESSIDE \I’ednesday 6th LOSDON Thursday 7th GL ASGOW Thursday 7th rdONDON Friday 8th CARDIFF Tuesday 12th BIRMINGHAM \17ednesday 13th \TARRINGTON ivednesday 13th LONDON ATOMIC SPECTROSCOPY GROUP Annual General Meeting followed by a meeting Speakers W. T. Elwell J. B. Dawson W. J.Price and W. R. Nall. Followed at 6.45 p.m. by the 10th Anniversary Dinner. Caf6 Koyal Regent Street London W. 1 ; 2 p.m. NORTH EAST REGION on “The Analysis of Gaseous Effluents.” “It’s in the Air,” by B. T. Leadbeater. “Field Methods for the Determination of Airborne Toxic Contaminants,” by “Sampling and L4nalysis of Airborne Contaminants to *\Sssess the Effect on Marton Hotel and Country Club Stokesley Road Marton Teesside; 2 p.m. SAC/AD. “Molecular Complexes in Analytical Chemistry,” by -4. Townshcnd. Scientific Societies Lecture Theatre 23 Savile Row London W. 1 ; 4 p.m. SCOTTISH REGION jointly with the Glasgow and West of Scotland Section of the “Atomic Spectroscopy and Pollution Control,” by Professor T. S. JVest. University of Strathclyde Glasgow ; 4 p.m. BIOLOGICAL METHODS GROUP Annual General Meeting followed by a Discus- sion Meeting.Discussion on “Biological Standards” will be introduced by D. R. Bangham. London ; 6 p.m. WESTERN REGION jointly with the South East Wales Section of the CS. “Some Views on the Cost Effectiveness of analytical Research,” by C. Whalley. University Staff Dining Club Park Place Cardiff; 7 p.m. MIDLANDS REGION and SPECIAL TECHNIQUES GROUP. “Ion-beam Thin-foil Spectroscopy,” by I. Martinson. Lecture Theatre Haworth Building The University Edgbaston Birmingham NORTH WEST REGION. “Principles and Applications of Activation Analysis,” by G. K. Gilmore. Universities Kesearch Reactor Risley Warrington ; 2.30 p.m. MICROCHEMICAL METHODS GROUP Debate on the motion “That this House Considers that the Microchemical Methods Group has Outlived its Usefulness.” For the motion Professor R.Belcher and D. A. Pantony. Against the motion Professor T. S. West and D. W. Wilson. Imperial College Senior Common Room South Side Princes Gardens London S.W.7; 6.30 p.m. on “The Past Ten Years.” E. C. Hunt. Health,” by B. T. Commins. CS and the Andersonian Chemical Society. 15; 6.30 p.m. SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Forthcoming Meetings November Tuesday 2 1st I,ONDON SPECIAL TECHNIQUES GROUP Annual General Meeting followed by a meeting “The H.F. Plasma Torch,” by S. Greenfield P. B. Smith and H. XIcl). “The Microwave Plasma Torch,” by R. 11. Dagnall and B. 1,. Sharp. “The Plasma Jet,” by E. A. du Bois and l i . Marriott. Lecture Theatre A College Block Imperial College London S.W.7; 2.30 p.m.\Vednesday 22ncl CHROMATOGRAPHY AND ELECTROPHORESIS GROUP .Annual General Meeting followed by a meeting on “Polymer Characterisation by Chromatographic Means.” “Isomerisation Problems in the Analysis of some Polyester Resins,” by D. I?. G Pusey. “The Applications of Gel Permeation and AffinitlT Liquid Chromatography t o the Analysis of Polybutadienes,” by R. J . J . Sinikins and E. J . Gallacher “Decomposition Products of Xylon,” by G. C. East C. J . Lupton ant1 E. 17. Truter. Polytechnic of the South Bank London S.E. 1 ; 2.30 p.m. on “Plasma Excitation in Spectrochemical Analysis.” McGeachin. T,OXDON iveclnesday 22nd PARTICLE SIZE ANALYSIS GROUP ,Annual General Meeting followed by a “The Methods of Inspecting Intravenous Fluids for Particulate Contamination,” “Particle Size Analysis of Pharmaceutical Aerosols,” by J .H. Bell. “The RBle of Particle Size in Tabletting Operations,” by K. ilfarshall. Chelsea College of Science and Technology RIanresa lioad London S.IV.3 ; LONDON meeting on “Applications of Particle Size Analysis t o Pharmacy.” by M. J . Groves. 2.30 p.m. \Vednesday 22nd MIDLANDS REGION. LOUGHROROUGH “Enhancement of Chemical Measurement Techniques Using On-line Digital lioom J O O l Edward Herbert Building University of Technology Laugh- Computers,” by Professor S. P. Perone. borough; 2.30 p.m. Thursday 23x1 LONDON Monday 27th LONDON THERMAL METHODS GROUP Annual General Meeting followed by a meeting “Thermal Decompositions in Inorganic Compounds,” by Professor I). \V. A\. “The Thermal Decomposition of Manganese Oxy-salts and Manganese Oxide “Thermoanslytical Studies of Pyrotechnic Mixtures,” by F.S. Scanes. “The Thermal Decomposition of Some Double Carbonates,” by li. M. McIntosh “Application of Thermal Analysis to S.T.C. Thermistors,” by E. D. hlacklcn. “Thermal Analysis of Serpentine Asbestos and Related Minerals,” by L. I;. lioyal Astronomical Society Rurlington House London \V. 1 ; 10 a.m. RADIOCHEMICAL METHODS GROUP Annual General Meeting ; 6.30 p.m. MICROCHEMICAL METHODS GROUP Annual General Meeting; 7 p.m. EDUCATION AND TRAINING GROUP Annual General Meeting; 7.30 p.m. Followed by a Joint Social Evening. Imperial College London S.W.7. on “Inorganic Applications of Thermal Analysis. ” Sharp. Transformations,” by K. H. Tonge. and J . H. Sharp. Monkman. followed by the Address of the Retiring Chairman Dr. \Ir. J . Williams. [continued inside back cover Printed by W Heffer & Sons Ltd Cambridge England

ISSN:0037-9697    

DOI:10.1039/SA97209BX045

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

November I972 Vol. 9 No. I I PROCEEDINGS OF THE SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Reports of Meetings JOINT MEETING A JOIKT Meeting of the SAC/Analytical Division and the Pesticides Group of the SocietJ- of Chemical Industry was held at 11 a.m. on Wednesday November lst 1972 at the school of Pharmacy Brunswick Square London W.C. 1. The subject of the meeting was “Multi-residue Detection Systems.” The Chair at the morning session was taken by the President of the SAC/Analytical Division Mr. C. \5’halley and the following papers were presented and discussed “Introduction,” by JI. Sliarratt ; “Mercury and Organochlorine Residue Analysis of Fish and Aquatic Mammals,” by A. 1’. Holden. The Chair at the afternoon session was taken first by the Vice-president of the Society of Chemical Industry Dr.H. Egan and later by the Chairman of the Pesticides Group of the Society of Chemical Industry Dr. R. A. Galley and the following papers were presented and discussed “Determination of Residues Arising from Fumigation Practice ” by S. G. B. Heuser; “Organophosphorus and Carbamate Detection Systems,” by J. H. A. Ruzicka; “The Isolation and Identification of Toxic Mammalian Metabolites of Phosphorothionate Pesticides,” by A. F. Machin; “An Approach to the Detection of Pesticides Poisoning in \I’ildlife,” by P. J. Bunyan; “One of the Problem Families-the PCRs,” by R. Edwards. NORTH WEST REGION Ax Ordinary Meeting of the Region was held at 7.30 p.m. on Thursday October 5th 1972 at the Harris College Preston. The Chair was taken by the Chairman of the S.C.I.Liverpool Branch Dr. D. W. Broad. A lecture on “Environmental Conservation An Analyst’s View” was given by G. R. Crump. A JOINT Meeting of the Region with the Liverpool Branch of the Pharmaceutical Society of Great Britain was held at 6 p.m. on Wednesday October 18th 1972 at Evans Medical Ltd. Speke Liverpool. The Chair was taken by the Chairman of the North West Region Mr. G. F. Longman. The lecture was preceded by a visit to the Tablet Production Department of Evans Medical Ltd. A lecture on “Tablet Manufacture” was given by A. W. Newberry. SCOTTISH REGION AND EDUCATION AND TRAINING GROUP A JOINT Meeting of the Scottish Region and the Education and Training Group was held at 2 p.m. on Friday October 20th 1972 in the University of Strathclyde Cathedral Street Glasgow.A discussion on “Training of Food Analysts” was introduced by R. 31. Johnson J. Thomson and D. R. Osborne. The Chair was taken by the Chairman of the Scottish Region Dr. J. A. Hunter. WESTERN REGION AN Ordinary Meeting of the Region was held at 7 p.m. on Friday October 6th 1972 in the Chemistry Department The University Bristol. The Chair was taken by the Chairman of the Region Dr. J. D. R. Thomas. A lecture on t selectrode-The Universal Ion Selective Electrode” was given by Professor J Rhiita. 23 1 232 REPORTS OF MEETINGS LProc. SOC. Analyt. Chem. MIDLANDS REGION A4x Ordinary Meeting of the Region was held at 4 p.m. on Thursday October 19th 1972 at Allied Breweries (U.K.) Ltd. The Brewery Burton-on-Trent. The Chair was taken by the Vice-chairman of the Region Mr. S. Greenfield.A lecture on “Analytical Problems in the Brewing Industry” was given by G. A. Howard. The lecture was preceded by a tour of the brewery and a visit to the Research Department. NORTH EAST REGION A SOCIAL Meeting of the Kegion was held at 6.30 p.m. on Tuesday October loth 1972 at the Scotch Corner Hotel Richmond. The Chair was taken by the Vice-chairman of the Region Nr. J. Whitehead. The Dinner was followed by a talk on “Consumer Protection” by 11. Kellner. BIOLOGICAL METHODS GROUP AN Ordinary Meeting of the Group was held at 2.30 p.m. on Thursday October 19th 1972 at the Pharmaceutical Society of Great Britain 17 Bloomsbury Square London W.C.l. The Chair was taken by the Chairman of the Analytical Methods Committee Dr. D. C. Garratt. The subject of the meeting was “Non-prescription Antibiotics in Animal Foodstuffs Their Nature and Analysis” and the following papers were presented and discussed “Flavo- mycin,” by G.Nesemann; “Virginiamycin,” by B. Boon; “Zinc Bacitracin,” by Mrs. €3. Grynne. ATOMIC SPECTROSCOPY GROUP AN Ordinary Meeting of the Group was held at 2 p.m. on Wednesday October l l t h 1972 at the Chemical Laboratory The University Lensfield Road Cambridge. The Chair was taken by the Chairman of the Group Mr. W. R. Nall. The subject of the meeting was “Atom Reservoirs” and the following papers were pre- sented and discussed “Flames and Alternatives to Flames,” by L. de Galan; “Chemistry of Metals and Free Radicals in Flames,” by E. h4. Bulewicz; “Determination of Non-metal Atoms in the Vacuum U.V.,” by D. Husain. PARTICLE SIZE ANALYSIS GROUP A RIEETmG of the Group was held on Wednesday and Thursday September 13th and 14th 1972 at The University Salford.The meeting took the form of a Colloquium on “Techniques for Particle Characterisation.” The meeting was divided into Sessions as follows. Session I Chairman Mr. P. R. Kiff ; “Ancillary Techniques,” by H. J. Scullion. Session I1 Chairman Dr. N. G. Stanley-Wood; “Size Limiting Gauges,” by P. R. Kiff. Session 111 Chairman Dr. W. Carr; “Projected Area Measurement and Microscopic Techniques,” by M. I. Barnett. Session IV Chairman Dr. I<. Marshall; “Hydrodynamic Techniques,” by R. G. Blezard. Session V Chairman Dr. M. J. Groves; “Volume Measurement,” by T. Allen. Session VI Chairman Mr. E. G. N. Marsden; “Surface Area Measurement,” by N. R. Thompson. Session VII Chairman Dr. T. Allen; “Presentation of Data and Statistical Analysis of Results,” by C. R. G. Treasure. JOINT PHARMACEUTICAL ANALYSIS GROUP A DISCUSSION Meeting of the Group was held at 2.30 p.m. on Thursday October 12th 1972 at the Pharmaceutical Society of Great Britain 17 Bloomsbury Square London W.C.l. The Chair was taken by the Chairman of the Group Dr. B. A. Wills. A discussion on “High Pressure Chromatography” was introduced by M. Pinnegar F. Bailey and K. Wilkins.

ISSN:0037-9697    

DOI:10.1039/SA9720900231

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

233 The Electroanalytical Group F. I HE 1l:lectroanalytical Group was formed in 1969 following an ariialgamation lwtm-em tlitb SA(' and the former Polarographic Society. The latter Society was formed in 1954 t>y a vvr!- active group of polarograpliers and during the next 10 years it enjoyed wide support and yla!-ed a major r6le in the promotion of electroanalvtical chemistry in this country. I n addition to publishing a major journal it was also responsible for orgariising tlie Second anti Third Iriterriational Conferences on Polarography (Cambridge 1959 and Southampton 1964). The Society received further stimulus when in 1959 its President Professor J . Heyrovskg rec.ei\.ed tlie Kobe1 Prize for chemistry in recognition of his invention and development of tlich technique. Ihring tlie late 1 960s tlic field of electroanalysih broadened considerably and it \ decided tliat the intervsts of the Societjr could best tie served by being associated with the wider arena of analytical chemistry.I'ollowing the merger several of the members of the Council of the Polarographic Society were active on the Committee o f the new Group in particular Mr. J. V. \Yestwood the present Chairman n.ho \vas Editor of the I'olarograpliic. Society Journal for most of its existence. -. llie first 3 years of the new Group have been marked by an upsurge of interest in electro- analytical chemistry mainly due to the introduction and development of ion-selective elec- trodes. Fortunately the novelty of these devices has now largely disappeared and they are finding their appropriate place in the armoury of analytical chemistry. However it seems verj- appropriate tliat in 1972 just 50 years since the invention of polarograyhy we are seeing a renaissance in the polarograpliic method itself with the development of ultra-sensitive trace techniques and also with its application in new areas such as organic biochemical and clinical analysis.

ISSN:0037-9697    

DOI:10.1039/SA9720900233

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

23-1 RECENT ADl’ASCES IS GEXEKAL ANALYTICAL CHEMISTRY PVOC. SOC. A?Z~ZJ$. c * / l C l l ? . Recent Advances in General Analytical Chemistry SAC Symposium Glasgow March 22nd to 25th 1972 ’[HE hrst Syniposium to be lield by tlie Society for Analytical Chemistry since its designation as the Analvtical Division of The Chemical Society took place at the Cniversity of Glasgo~ in Jlarcli this year. I t was organised in honour of Cecil L. IVilson Professor of Analytical (’liemistry in the Queen’s Vniversity of Belfast in recognition of his long and varied service5 to the teaching and practice of analytical chemistry and also in celebration of his 60th birtliday. ‘[‘lie original intention had been to hold the Symposium at the Queen’s University but the pi’litical disturbances in Belfast led to a change of venue to Glasgow where tlie I-niversitl- of Glasgo\v welconied tlie Symposium and arranged for the scientific sessions and esliibition5 to be held in their new Basic Scit.ncc5 Building wliicli liad just been completed and liad still to be formally opened.Delegates assembled in Glasgmv 011 \2‘ed- nesday March 22nd ; residential acconmoda- tion was provided in tlie Queen 3Iargaret Hall of the ITniversity wliicli also acted a< a focus for the Social Programrne. Tliis hcgan immediately after Iyednesday’s dinner nit11 a “mixer” -an informal and convivial reimioii of old friends and an opportunity for making new ones among the delegates. An iiitri)duc- tion to both Northern Ireland and to S(-otland was provided in the form of entertaiiimcnt delegates were invited to taste both Triyli and Scotch ivhiskies there was a display o f traditional Scottish Dancing and a series of slides providing “a lighthearted introduction ’ ’ to both countries was shown during the evening compered by Mr.E. Donaldson of the .Ifinistry of Commerce for Sortliern Ireland and Dr. K. A. Chalmers of Aberdeen University. The work of the Symposium began in the lecture rooms of the University’s Basic Sciences Kuilding on Tliursday morning with a short Opening Address by the President Mr. C. Whalle>- a welcome to Scotland by Dr. D. Ill. W. Anderson and to Glasgow University by Professor ti. A. Sim. With the President in the Chair Professor R. Relcher (Professor of Analytical Chemistry in the University of Birmingham) gave the first of the two plenary lectures his subject being “Some Myths and Legends in Analytical Chemistry.” Professor Relcher’s practical demonstrations of many “mythical” reactions were as ever delightful to watch.The Trades Exhibition also held in the Basic Sciences Building was open during the break that followed; in accordance with the Society’s established practice refreshments were served in the Exhibition area to everyone’s greater convenience. .? ‘3 j h’ovt*niher 197% RBCEXT I\T)’I’AN 1;or tlie scientific papers and discussions on them delegates divided into two streaim. (’areful programme planning and strict adherence to schedules permitted easy interchange hctween the streams as the lectures were in adjacent theatres ; altliougli one or two delegates found they would liave liked to have been i n two places at once there were very few real ies” of interest which reflects great credit on the care with whicli tlie Scientific Pro- gramme Committee arranged tlie sessions.The final programme was only slightly changed from that published in the January issue of Pyaccrdings (pp. 22 arid 23) the paper on ‘ T i e Direct Thermometric Determination of Karbiturates in Dosage 1;orm” by A. E. Keezer and \Y. 1;. Smvth of Clwlsea College of Science and Technology was withdrawn and replaced lib ‘ ‘ €’( ) 1 )gray h i c i n a 1 y si s of Certain Hypn( )ti c -Tr an q uil1 ise r Formula t io n s ’ ’ by \V . I ;. Sni y t I I :tnd t\vo additional papers were included at tlie end of Stream 13 on Friday P Z Z . “Tlie Perform- ariw at High and I m v Concentration Ixvels of a New Atomic Absorption Spectrometer” 1))- \I7. ,I.Price and P. Jolins of P37e I’nicam I,td. (’ambridge and “Investigation of Ttiermal I’ro1)ci-t ies of High Temperature Systems by A4rc Spectroscopic Rletliods” hv T. Iiantor and I:. I’ungor of the Tee-linical Vniversitj- lZudapest Hungar),. I S G E KBK AL ‘1 S AL YI-I CX L C H 1; &I I STK 1- i? . Professor E . Koros presenting a silver cigarette box to Pvo ft’ssov Wilson Professov Wilson receiving a Globe of the mediaeval world from the President ( > n Thursda>- CLI-ening the main social event tlie Symposium Banquet was lield i n the Iii\toric wtting of tlie I3ute Hall of the Cniversit!.. .After the 1,oyal Toast proposed hj- tliv Prr.\ident Dr. J . Hunter C‘hairman of tlie Scottish Region proposed tlie Toast of “Tlits ITni\7ersitjr o f Glasgow.” He had found some intriguing facets of the I’niversity’s liistory for instance in its earl) years all lectures had been delivered in Latin -and tlie Kegents of thc I’niversity liad promptly had to appoint a “Teacher of Humanity” ( i ~ .of La tin) so that ytudcnts could learn to understand their lectures. Perhaps Dr. Hunter suggested matters liad not changed niuc11 and there were today many students who could profit from a wurse in tlie understanding of lectures ! However ’The Liniversity of Glasgow had produced man?. emincnt chemists such as Black and James \Vatt wliose name was nowadays associated with +:dinhurgli in the Herriott-Watt University. Nevertheless he felt it a matter of regret that a I‘ni\.ersity that had in 1760 no less than tliirteen full Professors still had no Professor o f Analj-tical Chemistrj,.Professor Sim responded for the University and also proposed the Toast of the Analytical Dii,i4on of tlie Chemical Society arid the Society for Analytical Chemistry wliose first sympo- sium -under the new regime-this was. Glasgow he said with its Presbyterian outlook had always had close associations with Northern Ireland indeed it was recorded during the 18th Century that a third of the student population were from Ulster. Ulstermen had played a very significant r6le in Glasgow aniong them were the eminent chemist Joseph Black and tlie physicist Lord Kelvin. The University which dated from 1451 liad established a Clieniistry Lectureship in 1747 although the first holder William Collin had also “doubled” as Professor of Medicine. Both he and liis successor Joseph Black were eventually enticed to ISdinburgl-I which offered a Chair of Physics and Chemistry.Black born in France with a I3elfast man o f Scottish descent as father made his famous researches into the composition 236 RECENT ADVANCES I N GESERAL ANALYTICAL CHEMISTRt- r Y I / O C . SOC. Analyt. Chelll. o f carbonates in Edinburgh; during his time in Glasgow he had worked on latent heat and although his fame was associated with the carbonates his Glasgow work had also been import- ant for it had led in turn to \fTatt’s experiments with the steam engine-and this liad given impetus to the Industrial Revolution. In tlie early years of the 19th Century tlie cliair had been upgraded to Kegius Professor o f Clieniistry by King George 111-an act considered by loyal Scotsmen as being an isolated instance of a good deed by an otherwise highly disreputable Hanoverian monarch ! The first occupant of the Chair Thompson received a stipend of L50 per annum.He was not himself an analyst but he had been impressed by the way tlie Analytical Ilivision represented one of the most important branches of chemistry. Its strong links with both the academic world and the industrial world contrasted with the tenuous links that lie and liis fellow members of the Dalton Division seemed to have. In proposing the Toast he stressed the r81e that the Analytical Division and the Society for Analytical Cheni- ihtrg played in demonstrating to the “outside world” the importance of chemistry in real life. The President MY. C . Whalley in conversation with the two plenary lecturers Professor R. Belcher (L) and Professor H .Weisz (R) Mr. C. \$%alley the President responding expressed his pleasure that no less than seven Professors of Analytical Chemistry were among the distinguished gathering of delegates from all industries and indeed all walks of life. The large attendance at the Symposium was indicative of the Analytical Division’s importance and wide-ranging interests. The formation o f the Division at the beginning of the year had brought about a large increase in membership -and with it increased administrative problems. ,411 organisation previously geared to serv- ing about 2000 members now served upward of 5000 and the Group Membership now totalled over 60 000 (although of course many members had joined several groups). One of the Division’s many activities was the provision through Symposia such as this one of oppor- tunities for younger members to present their work for discussion and the President took the opportunity to thank all the lecturers especially the plenary lecturers Professors Relcher and Weisz for providing the core of the Symposium.He also thanked the organisers particularly the Programme Committee and its Chairman Dr. D. Betteridge and Secretary Dr. D. I. Coomber for their part in the work. On behalf of all the delegates he thanked the University for allowing the Symposium to be held in its Chemistry Department and the dinner to be held in this historic Hall and also the Warden and staff of Queen Margaret Hall for providing comfortable living quarters. The Exhibitors too deserved delegates’ thanlts especially Pye Unicam,who had donated the document folders.Finally he especially thanked Dr. J. M. Ottaway Chairman of the Local Committee and his fellow committee-men for all the hard work they had put into the organisation of the Symposium; this was acclaimed with applause. November 19721 RECENT ADVANCES I N GENERAL ANALYTICAL CHEMISTRY 237 The President then referred to Professor Wilson’s approaching 60th birthday (on May l l t h ) which was being celebrated by this Symposium. He read telegrams of greeting from eminent chemists unable to be present and called on two representatives of overseas societies with which Professor Wilson had been closely associated to make presentations. Professor Weisz on behalf of the Austrian Chemical and Microchemical Societies presented Professor Wilson with a lithograph of the historic City of Graz as a memento of his association with that centre of microchemistry and Profesor E.Koros gave him a silver cigarette box on behalf of the Hungarian Academy of Sciences and the Hungarian Chemistry Society. Presentation to Professor Wilson by Mr. S. Bance Mr. Whalley said that Professor Wilson’s career and contributions to microchemistry had been admirably described in a preface to the Symposium Handbook but there were a few facets that deserved further mention. He had done much to further the science of chemical microscopy and had developed the quartz-fibre microbalance for ultramicro chemical analysis. In association with Professor Belcher and himself Professor Wilson had taken part in the activities of a Special Committee of the old Society of Public Analysts and Other Analytical Guests at the Symposium Banquet (L-R) Professor C.L. Wilson Mrs. Whalley Professor G. A . Sim Dr. J Hunter Mr. C. Whalley (President) Mrs. Wood Professor H . C . S . Wood and Mvs. Hunter 238 THE FIRST THEOPHILUS REDWOOD LECTURE [PYOC. Soc. Analyt. Chem. Chemists that had culminated a quarter of a century ago in the formation of the first Subject Groups and so had ushered in a new era for the Society. It was most appropriate that the first meeting of another new era in the Society’s history should be concerned with celebrating that era with which Professor Wilson had been so closely associated. On behalf of the Society which he had served so well throughout his career as an analytical chemist of real distinction and perspicacity Mr. Whalley presented to Professor Wilson a Globe showing the terrestrial sphere in mediaeval times.The programme for Friday began with the second plenary lecture entitled “Some Uses of Catalytic Reactions in Analytical Chemistry,” by Professor H. Weisz of the Chemische Institut der Universitat Freiburg West Germany the second half of the programme of presented papers followed arranged in two streams as before. The Exhibition again drew delegates’ attention particularly during the coffee and tea breaks. The Social Programme on Friday evening was informal. A wine and cheese party had been arranged and Professor Wilson gave an informal illustrated talk in the Library of Queen Margaret Hall which he announced as being on “Highway Byways Cul-de-Sacs and Gutters in Document Examining.” Professor Wilson has a considerable reputation in forensic examination of questioned documents and also as a raconteur ; he provided some unforgettable entertainment to delegates as he recalled for us some of the more humorous occasions on which he had assisted the Courts as an Expert Witness.During the evening Nr. S. Bance Chairman of the Microchemical Methods Group made a presentation on behalf of the Group to Professor Wilson who was one of its past Chairmen and had been associated with the Group since the days when it had been the Microchemistry Club. Although many delegates left on the Saturday morning there was as a final item a tour of the Trossachs and Killin which proved t o be a most enjoyable day spent seeing something of Scotland. Throughout the Symposium there had been a Ladies’ programme including an informal reception by Mrs. Whalley. Thursday’s excursion was to Culzean Castle in Ayrshire arid on Friday there was a morning tour of Glasgow with the afternoon left free for shopping.

ISSN:0037-9697    

DOI:10.1039/SA9720900234

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

238 THE FIRST THEOPHILUS REDWOOD LECTURE [ P m . SOC. Analyt. Chem. The First Theophilus Redwood Lecture* Fads and Fashions in Chemistry and Particularly in Analytical Chemistry BY PROFESSOR SIDNEY SIGGIA (Department of Clzemastry University of Massachusetts Amherst Mass. 01002 U.S.A .) LET us first define terms-A fad is a short-lived trend which usually disappears once it has run its course whereas a fashion is more permanent. Although a fashion may wane it usually influences succeeding trends so that vestiges of a fashion persist for long periods of time. In fact many fashions reappear in their original form. For example today’s fashions in clothing include vestiges of past fashions in that dresses are still worn by most women and some of the young women even dress in long dresses much like their great-grandmothers at the turn of the century.As for fads the swallowing of goldfish the cramming of telephone booths by students and the like have gone with little influence on our lives. We normally think of fads and fashions in connection with clothing automobiles hair styles and the like. However fashions consist of the manner in which we do things and Iience there are fads and fashions in our business lives as well as our personal lives. Management accounting education research personnel handling etc. vary in their modes of operation depending on the various influences to which they must respond. of the “New” Chemical Society held in Manchester on April 13th and 14th 1972. other papers presented at the Symposium appear on pages 242 to 254 of this issue. * Presented at Symposium I organised by the SAClhnalytical Division during the Inaugural Mceting Summaries of some o f the November 19721 THE FIRST THEOPHILUS REDWOOD LECTURE 239 Fads and fashions are brought about as a result of response to various influenccs on a particular sphere of activity.In this paper the various factors influencing the field of chemistry particularly analytical chemistry are discussed. On completion we should see the field as it exists today and the riile played by each element of fashion in getting us tlicrt?. IXFLUENCE OF THE “TIMES”- The mood of a particular period has a great deal to do with influencing the manner in ~ h i c h the human does things. Periods of war prosperity and economic and psychological stress strongly affect all facets of our lives. We in chemistry turned our attention to anti-malarials for our troops in the Pacific area; we took on the atomic energy efforts ; materials for radar ; new explosives ; photographic materials etc.Our chemical world had a central focus. Applied chemistry was the order of the day; all our energies were completely directed towards winning the war. After the war the large impetus in science toward the creation of new and useful materials carried us forward into a period of great prosperity. Fundamental research was now “good,” after all it helped us to win the war. Fundamental research was in fashion and every major (and some not so major) chemical companies expanded or created research facilities. The chemistry departments at our colleges and universities expanded both in research and educa- tional directions; in addition new colleges and universities were founded at a rate of one per week in the early 1960s.In the period from 1945 to 1963 new knowledge was being generated at such a rate that only a fraction of this knowledge could be assimilated. In about 1963 the pendulum reached the limit of its swing in the direction of fundamental research and our current period of comparative austerity began. The cost of industrial research had exceeded the profit that could be realised from that research. This resulted in cuts in research. Early cuts in research spending were easily absorbed but in 1967 we began to see curtailments in personnel. We may be nearing the end of this phase although it is too early to say with certainty. Today applied chemistry again rules since one can readily justify programmes which will make financial profits or that will profit mankind.I t is a period in which the knowledge surge of the post-war period had to be assimilated. Thus the “times” seem to create a periodicity in fashion between the applied and the pure aspects of our science the applied being “in” in times of stress and the pure research flourishing in times of affluence. The early 1940s were strongly influenced by World War 11. ISFLUENCE OF INSTRUMENTATION- In the 1940s owing to the war the demand was created for many chemical materials. Cp to that point chemical materials were manufactured in batch processes ; tlien ccntinuous processes were adopted to increase productivity. With continuous processes came the need for continuous monitoring i.e. analysis.As the classical methods of analysis were generally too slow for continuous monitoring instrumental systems had to be adopted. So we see old processes such as the caustic - chlorine ammonia sulphuric acid and petroleum chemicals production systems completely automated thus effecting higli outputs with a rather small number of people. The new instrumentation not only increased the efficiency of old processes but also made possible the development of new processes. We now could handle materials that previously could not be handled in production quantities. For example phosgene hydrazine (and derivatives) liquid oxygen liquid hydrogen hydrogen fluoride and other such dangerous materials are articles of commerce today because monitoring and production can be carried out by remote control.By its utility it quickly spread into other areas. So a new industry was created which now by the nature of things had to grow; Thus it had to create a demand for new devices beyond those required to fill our immediate needs. The instrument industry thus became one of our leading “fashion designers.” To sell more automobiles or clotlhg the manufacturers keep altering the styles eacli time usually incorporating an element of improvement over earlier products. To sell more instruments the instrument companies keep coming out with new models and also with Thus the instrument industry was initiated through need. 240 THE FIRST THEOPHILUS REDWOOD LECTURE [Proc. SOL. AnaZyt. Chem. new devices which they feel will be popular. For example no one was looking for a differential scanning calorimeter ; however the manufacturers forecast that if one was developed there would be a market for such instruments.They guessed correctly and the differential scanning calorimeter is now among our modern chemical fashions. Automated carbon - hydrogen - nitrogen analysers are another example. There was no demand until these instruments appea- red on the market and made their own way. Laser-Raman pulsed nuclear magnetic resonance photoelectron emission spectroscopy and many other measuring devices have been introduced in this manner with the instrument companies leading the way to new ways of doing things. The surge of instrumental modes of analysis that occurred from the late 1940s to early 1960s was great but had several undesirable aspects. Times were prosperous and sometimes people purchased sophisticated instruments to be “in fashion,” but often used them in instances where much less expensive methods could be used.For example automated on-line instru- ments were popular during this period. People purchased these devices to monitor systems where a spot analysis every three or more hours would suffice. Having the money they also purchased the more advanced model when simpler and cheaper models would do. This is waste. Many laboratories equipped themselves with rat her sophisticated instrument at ion but had a relatively unsophisticated staff to operate them. The momentum of the era of instruments carried the field so far that when the recession of the mid and late 1960s occurred many chemical companies found that they had high overheads and depreciation costs as a result of their earlier commitments in this direction.One of the first cost items frozen during this period was capital money for equipment. In the meantime the instrument industry had grown to such gigantic proportions that there was not now a great enough market to satisfy all companies and competition took its toll of profits. Some instru- ment companies closed down completely. Relating one incident that occurred in 1970; we were purchasing a liquid chromatograph and selected Model 1 manufactured by Company A. Before our bid was approved (3 months) Company B issued their Model 1 which was about 25 per cent. cheaper than that of Company A for a comparable device. Our bid was altered accordingly and the device from Company B was ordered. Before it could be delivered (4 months) Company A issued a Model 2 which was about 25 per cent.cheaper than Model 1 of Company B. Within the same year Company B retaliated with its Model 2. Imagine how difficult it is for an instrument company to recoup its costs with such short periods of obsoles- cence and with the pressure to keep prices down. Also it must be added that while the above was going on other instrument companies were going into the business of selling liquid chromatographs. The instrument business is now equilibrating with the chemical industry and educational institutions at a more realistic steady-state equilibrium. This was inevitable but painful none the less. The advent of the instrument era brought with it another fashion the instrumental specialist. To extract the maximum information that each of the modern instruments can yield and also to keep each type of instrument operating optimally requires a specialist who is trained in that speciality area.This is an absolute necessity with the complexity of the instrumentation and with the complexity and scope of knowledge needed to fully master the interpretation obtained by each approach. The need for analytical specialists by its very nature spawned a need for the analytical “general practitioner.” Visualise a plant explosion with the plant manager going to an analytical specialist for help in elucidating the cause of the explosion. The specialist will most likely apply his speciality to the problem whether it is the best approach or not in solving the problem. The general practi- tioner however looks at the problem with a broad outlook and can decide which of the specia- lities are best to attack this specific problem.The generalist then calls on the specialists to get the best data and interpretation of that data; he then looks a t all the accumulated data and either formulates a conclusion or decides what further work is needed. Besides the generalist and the specialist the instrument industry has given rise to a third type of analytical chemist the “do-it-yourselfer.” The instrument industry to reach markets beyond the strictly analytical chemical population has come up with inexpensive easy to operate models in each area of measurement. These devices are meant for the non- specialist to use for his immediate needs. These models usually have the minimum of knobs and dials some have only a red button for “stop” and a green button for “go,” and are made to This is chaos.After all his pattern of thinking is fixed by his experience. November 19721 THE FIRST THEOPHILUS REDWOOD LECTURE 24 1 be idiot-proof so that there is little harm that can be done by inexperienced people. Although these simple models play a large r81e in today’s technology they give the illusion that it takes little to master the particular measuring approach since it takes so little to operate the device. Although the instrument may have been made simple to operate the knowledge required to master the measuring technology and to obtain the most from the data has not been lessened. Indeed the instrument user must not only be able to interpret the data adequately he has to also be able to evaluate the data.Is it adequate for the purpose? Are there any artifacts in the data being interpreted as data? Is the device performing as it should (calibration checks) ? For example the author has seen a rash of “new products” discovered the findings based on infrared spectra where the wavelength scale had inadvertently been shifted so that absorption bands occurred at “different” wavelengths. He has seen attempts made to compare spectra run on two compounds one having been run neat and the other in solution-different spectra occurred and the operator claimed that the two samples were different when they were in fact identical. There was the case of the “do-it-yourselfer” who was proud of the gas chromato- graphic separation of his reaction mixtures into two components; on investigation a gas - liquid chromatography specialist observed no less than twenty six components and this on the specialist’s first run.Do-it-yourself jobs in analysis are of the same quality as do-it-yourself jobs a t home. A carpenter’s tools are easy to operate (easier than the tools used in gas - liquid chromatography and infrared spectroscopy) but somehow the book-case hung door or cabin built by the carpenter usually looks better holds up better and is finished quicker than the same jobs done by a do-it-yourselfer. There is no substitute for training experience and aptitude. We must remember also that it is the man behind the tools that does the job. INFLUENCE OF GOVERNMENTAL PRESSURE- The influence of governmental pressure is pronounced especially during these times of lean budgets.This pressure is exerted by the government subsidies of particular activities causing these areas (research education production etc.) to proceed along certain lines. For example environmental oceanographic biomedical and sociological areas are in fashion today because of the interest and the money to be had for work in these areas. Legislation in areas such as environmental pollution with pesticides and other chemical materials has increased analytical burdens on governmental agencies (Federal State and Local) and on the chemical industry to monitor and control solid liquid and gaseous waste disposal. Also governmental regulation on food additives food quality and truth in labelling has generated much analytical work. It is difficult to assess how much of the chemical and analytical work we do is a direct and indirect result of governmental influence but it is large.INFLUENCE OF FINANCIAL PRESSURES- The high cost of running chemical facilities had to be cut for companies to remain com- petitive. This surge towards economy has caused certain fashions to evolve. Automation developed rapidly to make efficient use of information gathered to help to make decisions and to optimise production by automatically controlling processes. Automatic process control makes production possible with operation of production facilities with the minimum number of staff and results in less off-specification material and an increase in general plant efficiency. If the automation was carefully evaluated and carried out the return on the investment could be high. Industrial labora- tories tend to keep all their instrumentation in a central analytical facility with services available to all.This practice keeps devices in the care of the specialists so that down-time is reduced optimum information gained fuller usage of the instruments is ensured and duplica- tion of instrumentation is avoided. Even colleges and universities are pooling their instru- ments in order to make their budgets go further. Tight money has also encouraged the purchase of services in cases where the demand for that particular service was low. Thus we see independent companies springing up to provide these services. Another fashion created by tight money is the pooling of facilities. Purchasing services can keep overheads down. INFLUENCE OF HUMAN PRESSURE- We have among us people of high capability and strong wills.This combination usually Differential scanning calorimetry results in the generation of new ways of doing things. 242 [PYOC. SOC. Analyt. Clzemn. mentioned above was the brainchild of a handful of people who not only envisaged the approach but had to overcome the non-believers within their own corporation then had to build a working device and finally had to convince the public that they had to have these devices. As a result of their tenacity and ability we have a new type of measurement. Mass spectrometry declined in popularity in the late 1950s but it cixme back into pro- minence as a tool for organic structure determination as a result of the ability and energy of a fen7 people. Behind every one of our chemical ways of doing things you will find the “missionaries” with ideas and the capability of making these ideas materialise. COKCLUSION- I t has been the object of this paper to enumerate what I feel to be the main forces to which we in chemistry and particularly analycical chemistry are responding and to show the effect of these forces in moulding us into our present configuration. RECENT TRENDS IN AXALY TICAL CHEMISTRY The nature of any sphere of activity is the net result of many factors.

ISSN:0037-9697    

DOI:10.1039/SA9720900238

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

242 RECENT TRENDS IN AXALY TICAL CHEMISTRY [ R o c . SOC. Analyt. Clzemn. Recent Trends in Analytical Chemistry The following are summaries of five of the papers presented at Symposium I organised hy the SAC/Analytical Division during the Inaugural Meeting of the “New” Chemical Society licld in lianchester on April 13th and 14th 1972. The First Theophilus Redwood Lecture presented at the Symposium by Professor S. Siggia appears in full on pages 238 to 242 of this iswe. A brief report of the Symposium was published in Chemistry in Britain 1972 8 298. Useful Effects of Steric Hindrance in Analytical Chemistry BY H. M. N. H. IRVING (Department of Inorgalzic and Stvuctural Chemistvy The Univevsity Leeds LS2 9 J T ) THE effects of differing molecular shapes and sizes relative to the steric occultative properties of a swollen gel network can form the basis of useful analytical separations.The same is true of clathrate (inclusion) compounds although these have found rzlatively few applications. ,4 distinction should be drawn between kinetic effects that are dependent ultimately upon steric considerations and the equilibrium (thermodynamic) effects which form the main subject matter of this paper. This point was illustrated by the slow reaction between chrom- ium (111) and EDTA and its catalysis by zinc dust. Steric effects in paper chromatography are illustrated by the behaviour of halogen- substituted indigos where a substituent adjacent to the NH or CO group (but not elsewhere) impedes intermolecular hydrogen bonding and produces enhanced R values. 2-Methyl-8-hydroxyquinoline fails to give a tris-complex with aluminium when con- ditions are used under which oxine does form such a complex but both reagents form com- plexes with a wide variety of metals which can be used in gravimetric titrimetric and ab- sorptiometric determinations and for liquid - liquid extractions.Determinations of mag- nesium (or chromium) in the presence of aluminium and of beryllium in the presence of aluminium can be made on this basis. The effect of alkyl substituents on the chelating properties of 2,2’-bipyridyl and 1,lO- plienanthroline was discussed. Steric hindrance to the coplanarity of the chelated molecule was shown to lead to reduced molecular extinction coefficients. Substituents adjacent to the nitrogen atom reduced the ability to form tris-complexes of metals such as divalent man- ganese iron cobalt nickel copper zinc and cadmium whereas (as illustrated by models or projections) bis-complexes were free from steric hindrance.This effect can be utilised fer the determination of copper in the presence of iron and the non-formation of a complex of copper(I1) and iron(I1) with biquinolyl and the production of a purple complex with copper(1) which can be extracted into pentanol was used to illustrate this point. November 19721 RECENT TRENDS IN ANALYTICAL CHEMISTRY 243 In liquid - liquid extraction the synergic effect on the extraction of planar complexes such as nickel diacetylbisbenzoylhydrazone and cobalt (11) bisacetylacetonate in the presence of substituted pyridines was shown to depend markedly on the position of the substituent.If the substituent is adjacent to the nitrogen atom there is a marked steric inhibition of the synergic effect. A similar case is exploited in gas chromatography by using active charcoal impregnated with cobalt (11) phthalocyanine. Here 2-alkyl substituted pyridines are eluted before pyridine itself despite its lower relative molecular mass. In the same category is the reaction of sodium pentacyanoamminoferrate( 11) with nitrosodimethylaniline to give a green complex. This reaction is inhibited by pyridine and derivatives that carry 110 cx- substituents (such as isoquinoline) giving a yellow solution whereas or-substituted pyridines (such as quinoline) are unable to co-ordinate and inhibit the formation of the green complex. These effects have been exploited in the quantitative determination of mixtures of pyridines although later techniques such as gas - liquid chromatography have displaced them.Thermal Analysis in Perspective BY R. C. MACKENZIE THERMAL analysis is definedl as “a general term covering a group of related techniques whereby the dependence of the parameters of any physical property of a substance on temperature is measured.” The name consequently includes a relatively wide range of techniques which are not necessarily closely related to analytical chemistry but which are currently becoming widely used in various scientific disciplines. Of those methods shown diagrammatically in Fig. 1 thermogravimetry (TG) and derivative thennogravimetry (DTG) differential thermal analysis (DTA) and differential scanning calorimetry (DSC) evolved gas detection (EGD) and evolved gas analysis (EGA) and dilatometry are extensively used and deserve comment ; a few others are also worthy of mention.(The Macaulay Institute f o r Soil Research Craigiebuckler Aberdeen) THERMAL ANALYSIS I Techniques dependent I Techniques dependent I Techniques I Techniques dependent on evolved on weight changes dependent on dimensional I I I THERMO- ISOBARIC ISOTHERMAL GRAVIMETRY WEIGHT- WEIGHT- CHANGE CHANGE MINATION MINATION DETER- DETER- I I I DERIVATIVE GRAVIM ETRY THERMO- DIFFERENTJAL THERMAL ANALYSIS DERIVATIVE DIFFERENTIAL THERMAL ANALYSIS on energy changes I changes DILATOfrlETRY I DIFFE~NTIAL DERI~ATIVE DILATOMETRY DILATOMETRY I I CURVES SCANNING HEATING DIFFERENTIAL CALORIMETRY vola I HEATING- RATE CURVES I INVERSE HEATING- RATE CURVES Fig. 1. Some thermoanalytical techniques and.their relationships I- EVOLVED GAS DETECTION lles I EVOLVED GAS ANALYSIS TG involves measurement of change in weight on heating and the DTG curve represents the first derivative (mathematical) of the TG curve. TG curves are determined on a thermo- balance many models of which are now commercially available.2 Recently there has been a general tendency towards the use of small tending to micro samples. TG curves show up all reactions associated with weight change whether dissociation volatilisation or oxidation, 244 RECENT TRENDS IN ANALYTICAL CHEMISTRY [Proc. SOC. Atzalyt. Chem. are quantitative for weight change and are therefore extremely valuable. As they are recorded at a constantly changing temperature however it is not always possible to relate the results directly to those that would be obtained at one specific temperature; indeed great caution must always be exercised in interpreting results obtained under a dynamic tempera- ture regime in terms of isothermal conditions.For example with rubidium-saturated montmorillonite it is easy to distinguish between hygroscopic and hydroxyl water because a plateau appears on the TG curve between the two weight losses whereas with a magnesium-saturated sample dehydroxylation apparently commences before dehydration is complete and no definite plateau develops.3 DTG curves can be obtained either by differentiation electronically during the TG determination or by manual plotting from the TG curve. They are particularly useful in revealing very small differences in slope that might be missed on TG curves and that are indicative of complexity of reaction.The area under the peak on a DTG curve is proportional to the weight change that occurs. DTA which involves measuring the difference in temperature between a substance and a reference material situated side-by-side in an environment that is heated or cooled at a controlled rate is probably the most widely used and generally useful thermoanalytical tech- nique. It reveals all energy changes that occur on heating a sample whether or not these are associated with weight changes ; consequently comparison with DTG curves immediately demonstrates which energy changes are weight-related. A wide range of equipment ranging from relatively simple to extremely sophisticated is now commercially available but care must be taken to choose an instrument that is compatible with the problem or the type of material being investigated.* Unlike TG and DTG curves DTA curves indicate all phase transforma- tions that occur on heating-not only melting and vaporisation but also polymorphic tran- sitions and solid-state reactions.Furthermore determination of the DTA curve during the heating and cooling cycles shows whether a particular transition is enantiotropic or monotropic. DTA however shows only that a change has occurred and does not give information on the nature of that change-which must be detected by ancillary methods such as X-ray diffraction or infrared absorption spectroscopy. Second-order transitions such as the glass transition in polymers are revealed by a shift in the base-line rather than by a peak.With suitable experimental d e ~ i g n ~ the peak area on a DTA curve is proportional to the energy involved in the reaction that occurs and hence for one reactant to the amount of reactant; this has been demonstrated by many workers (e.g. reference G) but difficulties can arise with certain specimen holders and when materials of widely different thermal diffusivity are involved. Divergences from a linear relationship between peak area and amount of reactant can on occasion give information on the mechnism of a r e a ~ t i o n . ~ ,4 limited amount of information on the kinetics of reactions can be obtained from both TG and DTA curves but care must be exercised in interpretation because ( a ) a dynamic temperature regime is used (b) heat-flow in powdered solids causes difficulty in deriving equations and (c) the physical significance of certain kinetic parameters for solids is uncertain.DSC is essentially a variant of DTA where the energy required to establish zero tem- perature difference between the sample and reference is measured instead of the temperature difference between the two. This gives a direct measure of the energy involved in a reaction and enables specific heat to be measured as well as heat of reaction. Purity determinations can be made from the shape and temperature of the melting peak obtained for materials of purity greater than 99 per cent.8 In the past the temperature range over which DSC could be used was somewhat limited because of radiation difficulties but recent developments have extended the upper temperature to about 800 "C.EGD and EGA particularly the latter are invaluable along with e.g. TG and DTA because they give direct information on the volatile substances involved and hence on the reaction that is occurring. As an example of EGD can be cited the thermal volatilisation analysis technique of McNeill and Neil.s EGA can be performed in various ways but the most common are by gas - liquid chromatography or by mass spectrometry particularly the latter. Connection of a mass spectrometer to a DTA intrument enables one to determine immediately whether for example a carbonate or a hydroxide is decomposing during a certain peak; specific peaks can also be associated with particular amounts of evolved volatite substances.1° A variant of EGA in which rapid pyrolysis of soils in vacua is followed by mass spectrometric examination of the volatile products is proving valuable in studies on soil organic matter.ll Other difficulties can also arise.November 19721 RECENT TRENDS IN ANALYTICAL CHEMISTRY 245 Dilatometry is traditionally perhaps associated with ceramics in which changes in dimensions on firing ware are particularly important. It can however also give information on other aspects e g . the glass transition in polymers12 and the changes that occur on heating a soap.13 Other thermoanalytical techniques that ought to be mentioned include measurement of electrical conductivity along with DTA; this can be used to detect the solution of salts in water of crystallisation on heating14 and to reveal how the purity of a salt increases with repeated cry~tal1isation.l~ Another technique that has recently been developed enables the sound emitted during e.g.a phase transition to be analysed both for frequency and for intensity,15 thus opening a new field. There are now commercially available instruments for techniques termed thermal evolution analysis and emanation thermal analysis. The former is apparently specific for organic carbon and the latter gives information on inter alia structural disorder16 through measurement of emanation from entra.pped radioactive material. The thermoanalytical techniques currently available yield a wide range of information each has its own particular forte and each can be made quantitative for some property. Yet thermoanalytical techniques do not always either alone or even when used simultaneously,17 necessarily yield clear information on reaction mechanisms and optimum results on this aspect can be obtained only when they are used along with ancillary methods such as X-ray diffraction.1. 2. 3. 4. .> . 0. 7. 8. 9. 10. 11. 12. 13. 14. 13. 16. 17. REFERENCES Mackenzie R. C. Talanta 1969 16 1227. Keattch C. J. “An Introduction to Thermogravimetry,” Heyden London 19G9. Mackenzie R. C. Bey. dt. keram. Ges. 1964 41 696. Mackenzie R. C. and Mitchell B. D. in Mackenzie R. C . Editor “Differential Thermal Analysis,” Academic Press London 1970 Volume 1 p. 63. Wilburn F. W. Ph.D. Thesis Salford University 1972. Van der Veen A. H. Geologie Mijnb. 1968 47 469. Mackenzie R. C. in Mackenzie R. C. Editor op. cit. p. 497. Plato C. and Glasgow A. R. Analyt. Chem. 1969 41 330. McNeill I. C. and Neil D. in Schwenker R.F. and Garn P. D. Editors “Thermal Analysis,” Redfern J . P. in Mackenzie R. C. Editor op. cit. p. 123. Bracewell M. J. Geoderma 1971 6 1G3. Murphy C. B. Proc. 3rd Toronto S y m p . Thermal Analysis 1967 p. 9. Vold K. D. and Vold M. J. J . Amer. Chem. Soc. 1939 61 808. Berg L. G. in Mackenzie R. C. Editor op. cit. p. 343. Lranvik K. Paper read before Thermal Analysis Committee of Nordforsli Helsinki Finland Balek V. and Habersberger K. in Wiedemann H. G. Editor “Thermal Analysis 1971,” Birk- Paulik F. Paulik J. and Erdey L. 2. analyt. chem. 196S 160 241. Academic Press New York 1969 Volume 1 p. 353. March 1972. hauser Verlag Basel in the press. Collaborative Analysis and the Standardisation of Analytical Methods BY HAROLD EGAN (Department of Trade arzd Industry Laboratory of the Governwent Chemist Cornwall House Stamford Street London SEl 9NQ) COLLABORATIVE studies are a means to an end.The aim of a collaborative analytical study is normally to achieve a uniform method of laboratory procedure as a means of obtaining consistent analytical results between individual workers and in particular individual laboratories. The ultimate objective is usually the attainment of some acceptable commercial amenity or health standard. Such studies therefore set out in the first place to describe in detail the procedural approach to a single analytical method. The former Society of Public Analysts and Other Analytical Chemists considered a proposal for the formation of a commit- tee to deal with the standardisation of analytical methods some 50 years ago. At first it was decided that this proposal was impracticable because of the large amount of specialised work entai1ed.l Standardisation was certainly seen as a long-term process and to begin with a Standing Committee on the Uniformity of Analytical Methods was formed to act 246 RECENT TRENDS IN ANALYTICAL CHEMISTRY [Proc.SOC. Aizalyt. Chem. as a clearing house for standard methods which had already been developed outside the Society.2 By 1927 however the President Mr. E. R. Bolton spoke of various sub-committees having held many meetings and the members thereof having conducted a most prodigious number of analyses with the object of verifying the accuracy of the methods they proposed to adopt.3 The Analytical Methods Committee in its present form dates from 1935. Accuracy the closeness of the observed result to the true or accepted value can un- fortunately be dependent not only on the character of the analytical method and the reagents and equipment used but also on the analyst and the particular laboratory in which he works.Whether or not “accuracy” is usefully distinguished from “precision,” a method which is supremely accurate in the hands of a single individual is of limited value if it is unworkable by other analysts. Indeed this illustrates two extreme views-on the one hand a standardised analytical method set out in the fullest possible detail so as to leave the analyst with no individual discretion and on the other hand a referee analyst who uses whichever method in his professional judgment he considers suitable on each individual occasion. No doubt there are circumstances in which each of these situations is appropriate.But there are also many points between the two-how far for example should a method of analysis when written down specify in detail each piece of equipment each background stage of recovery calibration or blank experiment or how far (if a t all) does it suffice to mention these in general terms ? Standardisation in the chemical field was reviewed a t a symposium arranged by the Royal Institute of Chemistry in 1949,4 one of the main objects of which was to provide an oppor- tunity for the expression of opinion on the extent to which standardisation is desirable advantageous and practicable. Materials methods and apparatus were all considered and the potential danger of over-standardisation of methods was clearly recognised.The point was made and it is just as appropriate today that a standard method need not be a routine one since it might be too cumbersome for everyday use. Indeed added point is given to this aspect by the development of mechanical or automated analytical equipment which (despite the obvious potential) has not yet reached the point of standardisation to the extent that it has replaced manual reference methods. Problems arising in the course of the collaborative study of analytical methods were looked at in some detail in relation to individual types of methods a t a symposium organised by the Brighton School of Pharmacy in 1964 the proceedings of which were subsequently p~blished.~ This symposium followed the publication by the Society for Analytical Chemistry of the first edition of its volume of standardised and recommended methods of analysis.6 A supplementary volume7 appeared in 1967 and a completely revised edition is due to be published at the end of 1972.With the increase in analytical instrumentation in the past 25 years the older wet methods with which the concept of a collaborative study began and developed have largely been replaced by instrumental techniques which tend more and more to take the discr 4. ion out of the analyst’s hands. The origin of standardisation and its transition from primitive to sophisticated methods has been reviewed by Lament; in the course of which review he makes the point that a standard method is not so much one that is reserved for arbitration purposes as one that is selected for the ability of different analysts when using it to obtain harmonious results which sufficiently represent the true value.The development and subsequent widespread use in analytical chemistry of chromato- graphic methods and of gas - liquid chromatography in particular called for a reappraisal of approach towards collaborative studies. At first these methods were purely qualitative in character and whilst even today it is still necessary to consider carefully the distinction between “determination” and “estimation” when using such methods they have since achieved a standard of reproducibilty and accuracy which particularly when coupled with high sensitivity and specificity has afforded them a large degree of acceptance as a basis for quantitative work. The critical character of optimum conditions in thermal analysis was stressed elsewhere in the present symposium.This is an extreme example perhaps but many other modern techniques including infrared spectrophotometry and polarography have gone through just this stage (both before and after commercialisation of the equipment). Gas chromatography for example has opened up fields of quantitative analysis that were barely approachable by other techniques and in particular has called for a new type But this is not the complete picture. November 19721 RECENT TRENDS I N ANALYTICAL CHEMISTRY 247 of approach to collaborative work. The difficulties of description of new and detailed manipu- lative processes that involve a large degree of personal skill and subjective judgment have not been easy to resolve. The results of early studies of this kind were not unexpectedly disappointing especially when it is recalled that they were a t the same time seeking to achieve levels of sensitivity and specificity which until shortly beforehand had been regarded as impossible.But these very considerations acted as a spur to reach acceptable standards in these new fields and there have now been a number of useful collaborative studies of this kind. The present edition of the AOAC Methods book published in 1970 speaks in the general introduction of the “new challenges of multiresidue multiproduct methods,’’ one of which couples gas chromatography with clean-up techniques developed earlier for paper chromatographic methods for pesticide residues. This and a sweep co-distillation technique for organophosphorus pesticide residues in food are featured as highlights of the new edition of the Methods book.g With the notable exception of fertilisers and feedingstuffs for which detailed analytical methods are prescribed,1° there are relatively few methods of analysis in Britain which are laid down by Acts of Parliament or by regulations made directly under an Act.This will not necessarily be the case after the entry of Britain into the European Common Market however. The European Communities Bill first published in January 1972 makes provision for the alignment of the laws in Britain with the laws of the European Common Market and makes specific provision for example for changes in the law relating to food analysis and the methods to be used for this. In fact it invokes powers to make a wider range of statutory methods of analysis to be laid down under the Food and Drugs Act although whether this will be necessary remains to be seen.But whether for compositional analysis and the pro- tection of the consumers pocket or for other important and unavoidable issues of safety that have to be judged not only by U.K. standards (which are frequently regarded as exemplary) but also by those in less well developed areas there is bound to be an increase in interest in standardisation by governments. STANDARDISATION OF FORMAT- One product of the systematic approach to the evaluation of analytical methods has been the concept of standardising the format for the description of methods. The systematic approach to this has perhaps been most highly developed by the International Organization for Standardization (ISO) which has published a recommended layout for a standard method of chemical analysis.ll This sets out in systematic fashion a series of headings the use of which ensures a comprehensive approach to the description of the analytical process.There are seventeen of these commencing with “Title,” “Scope,” ‘‘Field of Application,” “Defini- tions” and “Principle” and concluding with “Schematic Representation of Procedure,” “Biographical Reference” and “Annexes.” The scheme also covers sampling and reporting aspects. I n drafting methods the details are dealt with in the sequence of these headings omitting any section that may be unnecessary in the particular case in question and adding if required further sections in the most appropriate place. The system is meant to be flexible and unless this is realised it can be misunderstood.The presentation of the results of chemical analysis has also been the subject of international recommendation by the Commission on Analytical Nomenclature of the Analytical Chemistry Division of the International Union of Pure and Applied Chemistry (IUPAC). This provides the necessary means for reporting results in a standardised form with the intention that by using the terms and symbols recom- mended the data are presented in an unambiguous manner without further explanation of terminology or method of computation.12 DESIGN OF COLLABORATIVE STUDIES- The importance of the design of collaborative experiments has become clearly apparent in the past 20 years. The basic statistics involved in the theory of error and experimental design were reviewed for the Royal Institute of Chemistry by Pantony in 1961.13 Of particular value is the booklet on statistical techniques for collaborative tests by Youden,14 based on lectures given to the Association of Official Analytical Chemists (AOAC) in Washington in 1961 and 1962.This sets out practical advice on the recognition of systematic errors the choice of number of analysts participating in a collaborative study the use of duplicate 248 RECENT TRENDS IN ANALYTICAL CHEMISTRY [PYOC. SOC. Analyt. Chem. analyses to assess precision and the problems of missing values and outliners. A ruggedness test for procedures for example is designed to reveal the need to specify in detail parts of an analytical process which are not described in the method circulated but which had been assumed as invariant by the laboratory that initiated the method.Features which might be concerned include the source of age of analytical reagents their concentrations rate of heating humidity or thermometer errors. To conduct the test reasonable minor variations are deliberately introduced into the standard method one at a time and the result observed. A “rugged” procedure will be immune to such variations; where great sensitivity is shown to a particular variation further investigation and standardisation is obviously called for. By introducing the variable factors in a systematic manner it is in fact possible to judge the influence of say eight individual variations in the method in several combinations in ten or so experiments. The co-operative type of analytical study in which results rather than methods are compared could be regarded as an extreme form of ruggedness test.COMPARISON OF ANALYTICAL METHODS- The SAC and the AOAC are only two of the many organisations that are active in the fields of collaborative study and the standardisation of analytical methods. Others in the international field alone include the ASTM IFJU ICUMSA ISO ACC IUPAC and ICSU itself through its Special Committee on Problems of Environment SCOPE. The question of comparison of analytical methods arises in a number of contexts typical of which are the circumstances referred to above. Which of two (or more) analytical methods should be accepted as the one to be used in the case of dispute? Kirkbright15 has referred in relation to spectrophotometric methods to the bewilderment that must face the newcomer to the field when considering the extensive literature which exists for a large number of less well known reagents.COLLABORATIVE ANALYSIS TODAY- The Analytical Methods Committee has over the years approved the publication of more than 150 methods all of which have been studied systematically on a collaborative basis. In addition to a joint committee with the Pharmaceutical Society at the present time it is served by ten Sub-committees concerned with antibiotics prophylactics and other additives in animal feeds metallic impurities fish and meat products essential oils fluorine analytical standards particle size and publications together with a joint Sub-Committee with the Association of Official Analytical Chemists in the United States which is at present trying to sort out a complex area of mercury intercollaboration.All of this work is directed towards essentially practical ends such as environmental safety or commercial acceptability in relation to matters of everyday concern and interest. Another such area of collaborative analytical chemistry in Britain is undertaken through various of its technical committees by the British Standards Institution. These committees indeed turn to the Analytical Methods Committee for suitable methods when such are avail- able for incorporation in the standards. This work also extends to the international area through ISO which is in turn linked with many other international organisations working in specific fields some of which also publish analytical methods developed on a collaborative basis.A good example of the latter is the International Commission for Uniform Methods of Sugar Analysis (ICUMSA) the constitution of which was first drawn up in 1936. ICUMSA provides an international forum for all matters pertaining to the science of sugar analysis and promotes the study of methods and the publication of international recommendations for uniform methods. One of the most comprehensive systems for the standardisation of analytical methods based on collaborative study is that of the AOAC in North America. Although designated an official body university industrial and consultant laboratories in addition to federal state and local government laboratories take part in its proceedings. Horwitz has described the manner in which methods are developed and ~ a l i d a t e d . ~ A central figure is the Associate Referee an experimental scientist who is appointed to study a problem area under a process predetermined by the Association an essential component of which is a collaborative study.Having reviewed the problem area devised or adapted a method tested it and found it successful in his own laboratory the Associate Referee proceeds with the collaborative study. November 19721 RECENT TRENDS IN ANALYTICAL CHEMISTRY 249 CONCLUSION- This of course is not to the exclusion of the academic aspects of analytical chemistry these have a full and proper place and have played an essential r81e in bringing analytical chemistry to its present state of advancement and there is indeed a strong and immediate interest in theoretical aspects as they are developed in the research laboratory such that they are very often closely followed in the applied field.Unlike the position in high-cost (or high-risk) technology the theoretical aspects of analytical chemistry may sometimes be followed too closely in the applied field. While this has on occasions resulted in a multiplicity of alternative methods for the measure- ment of the same substance the search for better methods remains a legitimate pursuit provided that the realities of the situations are recognised. Constraints of the kind recently outlined by Lord Rothschild16 may not be universally accepted as being appropriate to research in analytical chemistry but in so far as analytical chemistry is fostered for its utilitarian value there is obviously some need for giving the process of evaluation of the new methods a chance to catch up with the methodology itself.Otherwise there may be little point in developing new methods at all. It would certainly be wrong to impose a rigid constraint on the choice of method in all circumstances one of the main objectives of collaborative study should be to explore the extent to which flexibility can be built into an acceptable method bearing in mind the safety commercial or legal requirements of the position in individual cases. There is a great danger of retreading old ground but there is surely a great deal of scope at the present time for consolidating our present knowledge and for channelling if not limiting advances to those of the better understanding and use of information already available to us. Collaborative analytical studies are not new nor is the interest in such studies declining although there seems to be something of a change in balance as between industrial interest and academic interest in some areas.There is certainly an increase in the governmental and intergovernmental type of interest motivated by consumer protection (whether in the purely domestic area of food or clothing or in the “big spend” areas of aviation or defence) and by environmental conservation and matters of health and amenity. On the economic side financial support for collaborative analysis is (as in many other areas of every-day interest) not always as full as it ought to be. On the scientific side analytical methods that have been developed by collaborative study are an accepted part of industrial and government management the main difficulty very often now being which of two or more such methods should be adopted.The difficulty is frequently more of theoretical than of practical significance however except in the realm of international trade where (at least for the present) there is a substantial interest in focusing on a single arbitration method for whatever standard of acceptance or performance is under consideration. Perhaps there is no general need to unify alternative methods each of which has been found to be fully satis- factory on a thorough-going collaborative study but there is some prospect of harmonising such alternatives when they do not differ too radically one from another. Analytical chemistry is essentially an applied subject. 2 . 3. 4. 5. 6. c 8. 9. 10. 11. 12. 13. 14. 15.16. REFERENCES Dyer B. and Ainsworth Mitchell C. “Fifty Years of the Society of Public Analysts,” IV. Heffer Salamon M. S. Analyst 1924 49 173 (cf. p. 123). Bolton E. R. Ibid. 1927 50 183. Lect. Monogr. Rep. R. Inst. Chem. 1950 No. 5. “Collaborative Tests,” Pharmaceutical Press London 1964. Jolly S. C. Editor “Official Standardised and Recommended ,Methods of Analysis,” Society for Jolly S. C. Editor “Supplement to Official Standardised and Recommended Methods of Analysis,” Laurent J. Chirn. Analyt. 1968 50 267. “Official Methods of Analysis of the Association of Official Analytical Chemists,” Eleventh Edition “The Fertilisers and Feeding Stuffs Regulations S.I. 218,” H.M. Stationery Office London 1968. IS0 Recommendation R 78 Second Edition September 1969. Fennell R. W. and West T.S. Pure A p p l . Chem. 1969 18 439. Pantony D. A. Lect. Ser. R. Inst. Chew. 1961 No. 2. Youden W. J . “Statistical Techniques for Collaborative Analysis,” Association of Official Kirkbright G. F. Talanta 1966 13 1. “A Framework for Research,” H.M. Stationery Office London 1971. and Sons Ltd. Cambridge 1932 p. 189. Analytical Chemistry London 1963. Society for Analytical Chemistry London 1967. Association of Official Analytical Chemists Washington D.C. 1971. Analytical Chemists Washington D.C. 1967. 250 RECENT TRENDS IN ANALYTICAL CHEMISTR\- [PYOC. SOC. ,4 nnlyt. CJzcm. Data Handling in Laboratory Gas Chromatography BY D. R. DEANS (Inzpevial Chemical Industvies Limited Petrochemicals Division Reseavch and Dcvelopwient Department Billingham Teesside T S 2 3 1 J B ) THIS paper is intended to cover the field of data processing from the electrical analogue output of the gas chromatograph to the decision to take action on the basis of the chromatographic results.The approach is to discuss the objectives and problems of each stage in the data processing and to suggest some solutions mainly in the form of design philosophies. Detailed practical designs are not discussed. In designing a data handling system whether for a single gas chromatograph or for a large group of chromatographs probably the most important initial consideration is the question “HOW will the analytical results be used?” I t is very rare that the analysis of a mixture is an end in itself. Some decision has to be taken on the evidence of the analysis probably in conjunction with other evidence.In a research environment it may be what the next experi- ment should be; in a production environment it may be that a particular batch of material does or does not meet the required specification. Whatever the decision that has to be taken the data handling system should be designed to make that decision easy to take. The function of the data system print-out is normally two-fold-firstly to provide the basis for an immediate action decision (which can often be to take no action) and secondly to provide a record of essential data as the basis for an action decision in the future. These functions are the same for both research analysis and for control analysis. When immediate action decisions are to be taken there is usually considerably knowledge of the expected composition of the sample and the nature of the action decisions to be taken.It is strongly recommended that all the prior knowledge about an analysis is accumulated and used both in the design of the analytical method and to make sure that the print-out eliminates work and chances of error on the part of the operator. In using a computer to calculate results of a gas-chromatographic analysis it is possible to apply complex mathematical functions to compensate for such effects as base-line drift and to allocate areas to peaks that are only partially resolved. However in order to obtain good quantitative analysis under these circumstances it is necessary to know what effect base-line drift is having on the sensitivity of the detector. In allocating areas to partially resolved peaks it is necessary to know the shape the individual peaks take up in the presence of each other.Both of these parameters are variable and not predictable; it is therefore better to attempt to improve the chromatography so that the base line remains steady and the peaks are com- pletely resolved. In general the temptation to use a computer to overcome poor chromato- graphy should be resisted. It is preferable to use the computer to do the jobs it is particularly good at which include rapid comparison of calculated figures with prescribed figures and further calculation beyond sample composition. One area that deserves more attention than it gets in most commercial systems is that of elimination of operator - user errors. Large operator panels with many knobs buttons and flashing lights may be very impressive but in my opinion the setting of controls in any but the simplest possible manner can lead to errors.Any controls to be set ought to be clearly dis- tinguishable one from another by both sight and touch. A computer can be used to check some things for example the size of injection by comparing the internal standard peak size with a prescribed figure. In many ways the whole data handling and chromatographic system can be designed to avoid error-prone operations. Ion Sensors of High Specificity BY W. SIMON (Laboratorium fiir Organische Chernie Eidgenossische Technisclae Hochschule Ziirich Switzerland) ION-SELECTIVE membrane electrodes presently used for the selective detection of a given ion XI’ in solution in the presence of interfering ions N“ can be divided into four basic groups according t o the type of the membrane incorporated in the cell assembly1: November 19721 RECENT TRENDS I N ANALYTICAL CHEMISTRY (i) Glass membranes.2 (ii) Solid-state membranes- ( a ) homogeneous solid-state menibrane3-5 ; (iii) Liquid membranes*- (b) heterogeneous solid-state membrane.3y4y6 ( a ) electrically charged ligands (ion exchangers) as (b) electrically neutral ligands as membrane com- membrane components3y4 ; p o n e n t ~ .~ ~ ~ ~ ~ - ~ (PI) Immobilised enzyme membranes? .lo 25 1 There is little agreement regarding the method of expressing sele~tivities.~ For electrodes responding to i + 1 cations as well as for those responding to i + 1 anions the E.M.F. of the cell assembly may be approximated by .. . . .. Z F E.M.F. = Eo + and the so-called selectivity constant Kg& which measures the preference by the sensor of the interfering ions Nini relative to the ion M" to be detected is then given by .. Pot - (E.M.F. - E.M.F.1)zF - log (awi)z'ni + log aacz . . .. .. 2.303 RT log K,Ni - ____ where T is the absolute temperature; R the gas constant; F the Faraday constant; E a temperature-dependent constant; E.M.F. the E.M.F. of the cell assembly with a solution of activity a with respect to the ion M" to be detected as the sample; E.M.F. the E.M.F. of the cell assembly with a solution of the same activity with respect to the interfering ion NYi; a are the ionic activities; x is the valence of ion to be detected; and ni the valence of ith interfering ion ( z and ni are positive for cations and negative for anions). TABLE I SELECTIVITY OF TYPICAL ELECTRODES OF INTEREST FOR BLOOD ELECTROLYTE ANALYSIS Electrode Glass (11 per cent.Na,O 18 per cent. A1,0, 71 per cent. SO,) . . Glass (27 per cent. Na,O 5 per cent. 1,iquid membrane (antibiotic valino- 1,iquid membrane (antibiotic Glass (good pH electrode) . . . . A1,03 68 per cent. SO,) mycin) . . . . . . . . macrotetrolides) . . . . . . . . Liquid membrane (calcium didecyl- phosphate - di-n-octyl phenylphosphonate) . . . . Cation to be measured H+ Na+ K+ K+ NH,+ Ca2+ Approximate selectivity KE$ [equation (2)] KPi < References 11 2-4 12 2-4 Some selectivities obtained by means of equation (2) for typical ion-selective electrodes that are of interest for blood electrolyte analysis are given in Table I. It is obvious (see the third column) that electrically neutral antibiotics such as valinomycin7 and the macro- tetrolidess are attractive for the preparation of electrodes of high selectivity.Liquid mem- brane electrodes in which valinomycin is used as a membrane component give selectivities of *The membrane electrodes with a PVC matrix as suggested by Xoody and Thotnas4 are assumed to be liquid membrane electrodes. t In contrast to the membrane electrodes of the types (i) (ii) and (iii) these can be used for the detec- tion of electrically neutral species. 252 RECENT TRENDS IN ANALYTICAL CHEMISTRY [PYOC. SOC. Analyt. Chew,. K+ relative to Na+ that are higher by several orders of magnitude than those obtained with glass electrodes. Such electrodes are useful for the direct determination of K+ in blood Assuming equal mobilities of the complexes of the neutral lipophilic cation-binding ligand L with a cation 111” or an interfering ion N” within the membrane] the selectivity factor KFG may be described as the ratio K,/K of the equilibrium constants of the following salt extraction r e a c t i ~ n s ~ j ~ ~ ~ ~ KM IL Xl”(samp1e) + 2.X-(sample) + L(membrane) ~2 M”L(membrane) +x-X-(membrane) (3) N”(samp1e) + n-)(-(sample) + L(membrane -4 N”L(membrane) + n-X-(membrane) (4) These equations measure the extent to which the neutral molecule L can extract the salt from the sample solution into the membrane phase.The influence of coordination number properties of ligand groups dimension of the ligand steric interactions and solvent on the complexation of alkali metal and alkaline earth metal cations by electrically neutral ligands (carrier antibiotics model compounds) has been studied16 by using model calculations and has given certain information for tailoring binding molecules.Assuming that oxygen atoms are the coordinating atoms a lipophilic molecule of high selectivity for Ca2+ should be a multidentate ligand having preferably six coordinating atoms. To discriminate between mono- and divalent cations the thickness of the ligand layer should be as small as possible16; in addition both ligand and complex should be lipid-soluble. To achieve a high selectivity for Ca2+ relative to other alkaline earth metal cations the coordi- nating oxygen atoms should form a relatively rigid cavity with a radius of about 0.1 nm. However because rapid cation exchange is necessary the ligand system must have adequate flexibility so that a compromise between selectivity ie.high formation constant for Ca2+ and flexibility of the ligand must be made.l47l7 To eliminate competitive reactions with protons the ligand should not contain functional groups participating in acid - base reactions under working conditions. The preparation of a number of molecules meeting these re- quirements will be described e1se~here.l~ The structure of one representative has been published re~ent1y.l~ By using filter-paper (Type VCWP Millipore Corporation Bedford Mass. U.S.A.) impregnated with a 20 per cent. m/nz solution of this ligand19 on p-nitroethyl- benzene as the membrane in the cell assembly1 0.1 M NH,NO,I KCl(satd.) Hg2C1,;Hg sample L4g;AgC1 0.01 M KClljmembrane (5) and 0.1 M aqueous solutions of the chlorides of the different cations the selectivity factors given in Table I1 were obtained.lg In comparing Tables I and 11 the outstanding selectivity of the system especially in relation to Mg2+ becomes obvious.It is important to note that the system described is unlikely to be optimal for the determination of Ca2+ in blood serum. TABLE I1 Cation Ni Ca2+ Rb+ 1.; + Ha3+ Cs+ Sr2+ Na+ Li + Mg2+ SELECTIVITY FACTORS K& (0-1 ill SOLUTIONS) Membrane with A \ ligand (20 per cent. m/wz in p-nitroethylbenzene p-nitroethylbenzene Effect of ligand on I<,?: 2 x 10-1 8 x 106 2.5 x 10-8 9 x 10-2 6 x 106 1-5 x 10-8 8 x 10-2 1.3 x lo4 6.3 x 10-6 6 x 10-2 3 x 106 2 x 10-8 10-2 10 10-3 7 x 10-3 1.2 x 10’ 3.8 x 10-7 3 x 10-3 40 7.5 x 10-5 3 x 10-5 4 x 10-2 7.5 x 10-4 1 1 1 * Ratio of values in column 2 over those in column 3.November 19723 RECENT TRENDS I N ANALYTICAL CHEMISTRY 253 Calculations with a simple electrostatic model suggest a preference of a membrane electrode for large lipophilic cations if a lipophilic anion such as tetraphenylborate is incorpor- ated in the membrane.20,21 Although such electrodes have been suggested and u~ed,~2,,3 their full potentialities have not been realised. Incorporation of tetraphenylborate (TPB) in a PVC matrix as described in detail e l ~ e w h e r e ~ ~ ~ yields electrodes with life-times of over 4 months. Measurements with the cell give the response shown in Fig. 1 and the selectivities (relative to Cs+) presented in Table III.*l ExceDt wit 360 320 280 -log a Fig. 1. Response of cell 6 for different cations (E.M.F. relative to a sample solution 0.02 M in caesium chloride).The broken lines are the theoretical Nernstian slopes L small cations (K+ Cs-+) the response is in good agreement with equation This electro KFGiG 0 (theoretical Nernstian slope) for a large activity range. 1) with le also responds to large cations such as alkaloids and crypt ate^,^^ and has been used sucessfully for the determination of the critical micelle concentration of organic cations.21 As it responds to complexes of neutral molecules with cations (e.g. cryptates2*) and as there are glass electrodes available that show a response to the cations which are complexed by such ligands the simultaneous use of the two electrode systems offers novel possibilities for the deter- m inat ion of corn plex format ion constant s. 254 RECENT TRENDS IN ANALYTICAL CHEMISTRY [Proc.SOC. Analyt. Clzeun. TABLE I11 SELECTIVITY FACTORS (a = M) K& Sodium tetraphenylborate 9-nitrocymene PVC 25 “C Cation Nj Ca2+ .. .. . . . . K+ .. .. .. I . . . cs+ .. .. .. . . . . Acetylcholine . . . . .. Neurine . . .. .. . . Brucine.H+ . . .. ,. . . Sparteine-H+ . . . . . . K+ complex with ligand L* . . Tetrabutylammonium . . . . Tetraphenylphosphonium . . Hexadecylpyridonium . . . . Anion c1- CI- c1- I- Br- c1- HS0,- c1- I- Br- c1- * L = 4,7,13,16,2 1,24-hexaoxa- l,l0-diazabicyclo[8.8.8] hexacosane.‘a Although membrane electrode systems for the more or less selective detection of at least fifty ions and other species have been described,l to date only about twenty ions can actually be determined.* However with knowledge now available for the tailoring of selective ligands,16,20 the routine use of a wide range of membrane electrodes will become possible provided that satisfactory application techniques are developed.Such techniques are also lacking for many of the existing systems. This work was supported in part by the Schweizerischer Nationalfonds zur Forderung der wissenschaftlichen Forschung. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. REFERENCES Simon W. Wuhrmann H.-R. VaSAk M. Pioda L. A. R. Dohner R. and Stefanac Z. Angew. Eisenman G. “Glass Electrodes for Hydrogen and Other Cations Principles and Practice,” Durst R. A. “Ion-Selective Electrodes,” National Bureau of Standards Special Publication No. Moody G. J. and Thomas J. D. R. “Selective Ion Sensitive Electrodes,”Merrow Publishing Co.Frant M. S. and Ross J. W. Jr. Science 1966 154 1553. Pungor E. and T6th K. Analyst 1970 95 625. Pioda L. A. R. Stankova V. and Simon W. Analyt. Lett. 1969 2 665. Scholer R. P. and Simon W. Chirnia 1970 24 372. Eyal E. and Rechnitz G. A. AnaZyt. Chem. 1971 43 1090. Guilbault G. G. and Montalvo J . G. Jr. J . Amev. Chem. Soc. 1970 92 2533; Guilbault G. G. and Hravankova E. Analyt. Chem. 1970 42 1779. Baumann W. M. and Simon W. Helv. Chim. Acta 1969 52 2054. Stefanac Z. and Simon W. Analyt. Lett. 1967 1 No. 2 1. Pioda L. A. R. Simon W. Bosshard H.-R. and Curtius H. C. Clinica Chim. Acta 1970 29 289. Eisenman G. in “International Symposium on Modern Technology in Physiological Sciences Munich July 1971,” in the press. Wuhrmann H.-R. Morf W. E. and Simon W. HeZv.Chim. Acta 1972 55 in the press. Morf W. E. and Simon W. Helv. Chim. Acta 1971 54 2683; presented a t the Symposium on Molecular Mechanisms of Antibiotic Action on Protein Biosynthesis and Membranes June 1971 University of Granada Spain. Diebler H. Eigen M. Ilgenfritz G. Maass G. and Winkler R. Pure Ap@. Chem. 1969 20 93. Ammann D. Pretsch E. and Simon W. in preparation. -- Tetrahedron Lett. 1972 24 2473. Mori W. E. Diss. Eidg. Tech. Hochsch. Zurich 1972. Scholer R. and Simon W. Helv. Chim. Acta 1972 55 1801. Gavach C. and Seta P. Analytica Chim. Acta 1970 50 407; Coetzee C. J. and Freiser H. Baum G. Analyt. Lett. 1970 3 105. Dietrich B. Lehn J. M. and Sauvage J.-P. Tetrahedron Lett. 1969 34 2885 and 2889; Lehn Chem. 1970 82 433; Angew. Chem. I n t . Edn 1970 9 445. Marcel Dekker New York 1967.314 1969. Ltd. Watford 1971. unpublished results University of Arizona 1968. J . M. and Sauvage J.-P. Chem. Commun. 1971 440. 255 November 19721 SHORT COURSES Short Courses of Interest to Analytical Chemists Available at Universities Colleges of Technology and Polytechnics in the U.K.* SUBJECT Full-t iine couysest- Atomic Absorption and Emission Spectro- photometry \-apour Phase Chromato Spectrofluorimetry and graphy Re1 a t ecl 1 Ic t hod 5 Gcl Filtration and Electrophoresis -1spccts of Electro- analysis Part-time cozwsesfj- Instrumental course for Industrial Chemists DATES December 11-15 1972 February 12-16 1973 March or April 1873 (date to be arranged) March 26-30 September 24-28 1973 1973 October 10 1972 (23 Tuesdays e) PLACE CONTACT for further in formatioil Loughborough U.T.Dr. D. Thorburn Burns Department of Chemistry Loughborough University of Technology Lough- borough Leicestershire LEI 1 3TG. -4 s above A s above -4s above -4s above L4s above -4s above A s above A s above Thames P. Ah-. J . Mendham School of Chemistry Thames Polytechnic Wellington Street London S E.18. * This list does not contain courses already announced in earlier lists. The previous list appeared in i These are all-day courses lasting one or more days. $ Abbreviations C.T. = College of Technology; P. = Folytcchnic; I'. = 1-niversity; 1-.T. = 1-niversity $ These courses comprise weekly lectures extending over a period of several weeks. ilbbreviatioiis the May 1972 issue of Pvoceedzngs p. 122. of Technology. n = afternoon; e evening.

ISSN:0037-9697    

DOI:10.1039/SA9720900242

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

November 19721 SHORT COURSES 255 Notices INTERNATIONAL SYMPOSIUM ON COLUMN LIQUID CHKOMATOGRAPHY THIS Symposium organised by the Association of Swiss Chemists will be conducted under the scientific direction of G. Guiochon (Ecole Polytechnique Paris) J. F. K. Huber (Universiteit van Amsterdam Amsterdam) and W. Simon (Eidgenossische Technische Hochschule Zurich). The aim of the symposium is to illustrate the state of the art of a technique now experienc- ing a surging revival and there will he sessions on column design phase systems optimisation advances and trends in instrument design and new applications with emphasis on practical applications. The most important aspects of the field will be covered by invited speakers such as Craig HalAsz Karger Kirkland Knox Scott and Snyder. A limited number of submitted contributions will be accepted and a 200-word abstract should be sent to the Sekretariat des Schweizerischen Chemiker-Verbandes Falkenstrasse 12 CH-8008 Zurich Switzerland by December 15th 1972.Application forms can also be obtained from the above address and should be returned by December 15th 1972. CHEMICAL SOCIETY SYMPOSIUM ON ENZYMES MAY 2ND TO 4TH 1973 INTERLAKEN SWITZERLAND JULY 1 8 ~ ~ AND 1 9 ~ ~ 1973 EXETER THE dates for this Symposium originally suggested in the Agenda unfortunately clash with a related meeting to be held in Stockholm so intending delegates should note the revised dates of July 18th and 19th 1973. The eleven lectures provisionally arranged which cover the action nature and appli- cations of enzymes include one on isolation purification and characterisation and one on primary structure and conformation.Further details can be obtained from Dr. J. F. Gibson Chemical Society Burlington House London W1V OBN. 256 NOTICES [Proc. SOC. Analyt. Chem. SYMPOSIUM ON APPLICATIONS OF NUCLEAR DATA IN SCIENCE AND TECHNOLOGY MARCH 12TH TO 1 6 ~ ~ 1973 PARIS THE primary objective of this Symposium to be convened by the International Atomic Energy Agency is to serve as a forum for intercommunication between the users and the compilers and evaluators of nuclear data for applications in science and technology. Among the application areas to be considered are activation analysis; radioisotope and particle accelerator applications in medicine biology and industry ; fission reactors; and nuclear materials safeguards. Requests for additional information should be addressed to Dr. Leif Hjarne Nuclear Data Section Division of Research and Laboratories International Atomic Energy Agency P.O. Box 590 A-1011 Vienna Austria.

ISSN:0037-9697    

DOI:10.1039/SA9720900255

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

256 NOTICES [Proc. SOC. Analyt. Chem. Errata OCTOBER (1972) ISSUE. In the report of the Joint Meeting of the North East Region (p. 216) the Chairman of the Hull and District Section of the Chemical Society should have been named as Dr. R. B. Moyes and not Mr. A. H. Latimer who is Secretary of that Section. In the article on the Work of the Publicity and Public Relations Officer (p. 218) the number of regional sections mentioned at the beginning of the third paragraph should read six and not five.

ISSN:0037-9697    

DOI:10.1039/SA972090256b

出版商:RSC    

年代:1972

数据来源: RSC

摘要:

November 19721 PUBLICATIONS RECEIVED 257 Publications Received The publications listed below have been received by the Editor of The Analyst in which journal Rook Reviews will continue to appear. VIBRATIONAL SPECTROSCOPY OF SOLIDS. By P. M. A. SHERWOOD. Cambridge kfonographs i f 2 Physical Chemistry 1. Pp. xii + 254. Cambridge Cambridge University Press. 1972. Price k5.90. THE EDDY CURRENT DECAY METHOD FOR RESISTIVITY CHARACTERIZATION OF HIGH PURITY of Standards Special Publication No. 260-39. Washington U.S. Department of Commerce. 1972. Price $0.55. SCIENTIFIC RESEARCH IN BRITISH UNIVERSITIES AND COLLEGES. 197 1-72. DEPARTMEKT OF EDUCATION AND SCIENCE. Volume 1. PHYSICAL SCIENCES. Pp. xxii + 924. Price L6.50. Volume 11. BIOLOGICAL SCIENCES. Pp. xxii + 769. Price k6. Volume 111. SOCIAL SCIENCES.Pp. xxx + 690. Price k5.50. London Her Majesty’s Stationery Office. 1972. Edited by H. A. ELION and D. C. STEWART. Progress in Nuclear Enevgy Series I X Analytical Chemistry. Pp. viii + 269. Oxford New York Toronto Sydney and Brsunschweig Pergamon Press. 1972. Price i13.50. HAXDBUCH DER ANALYTISCHEN CHEMIE. Edited by W. FRESENIUS. Dritter Teil. QUAN- TITATIVE BESTIMMUNGS- UND TRENNUNGSMETHODEN. Band VIbp. ELEMENTE DER SECH- STEN NEBENGRUPPE. URAN. By J . KORKISCH and F. HECHT. Pp. xii + 524. Berlin Heidelberg and New York Springer-Verlag. 1972. Price DM169; $53.30. By T. ALLEN. 1972. Price L2. By KURT F. J. HEINRICH ROBERT L. MYKLEBUST HAKVEYAKOWITZ and STANLEY D. RASBERRY. Xalional Bureau of Standards Technical Note 719. Pp. ii + 50. Washington U.S. Depart- ment of Commerce.1972. Price $0.55. TABLES OF MOLECULAR VIBRATIONAL FREQUENCIES. Consolidated Volume 1. By TAKEHIKO SHIMANOUCHI. National Standavd Reference Data Sevies hTational Bureau of Standards N o . 39. Pp. iv + 160. Washington U.S. Department of Commerce. 1972. Price $3. THEORY AND INTERPRETATION OF MAGNETIC RESONANCE SPECTRA. Pp. viii + 164. London and New York Plenum Press. 1972. Price $16.50. IXTRODUCTION TO MOLECULAR PHOTOCHEMISTRY. By C. H. J. WELLS. Pp. xii + 146. London Chapman and Hall. 1972. Price L1-70. METHODS OF AFLATOXIN ANALYSIS. Tropical Products Institute Report No. G70. Pp. vi + 58. London Tropical Products Institute. 1972. nfETALS. By A. F. CLARK V. A. DEASON J . G. HUST and R. L. POWELL. National Bureuu Pp. x + 44. EMITTANCE AND REFLECTANCE SPECTROSCOPY. Volume 11. PARTICLE MEASUREMENT. SIZE AND SURFACE AREA DETERMINATION. BIBLIOGRAPHY 1969-1972. Pp. vi + 34. Published by the author a t the University of Bradford. -4 SIMPLE CORRECTION PROCEDURE FOR QUANTITATIVE ELECTRON PROBE MICROANALYSIS By \V. T. DIXON. By B. D. JONES.

ISSN:0037-9697    

DOI:10.1039/SA9720900257

出版商:RSC    

年代:1972

数据来源: RSC