摘要:

Proceedings of the Society for Analytical Chemistry Analytical Division Chemical Society CONTENTS Editorial .. . . . . Society for Analytical Chem- istry Gold Medal . . I . Reports of Meetings . . . . “Liquid Chromatography” . . “Original Papers in Pharm- “Particle Size Analysis” . . aceu t ical Anal ys i 5’’ . . Obituary . . . . . . Papers Accepted for The Analyst Notices . . .. . . .. Short Courses . . . . .. Publications Received . * Classified Advertisement . . I I 2 6 9 13 20 21 22 23 24 24 Forthcoming Meetings Bock Cover Proc. SOC. Analyt. Chem. Vol. 10 No. I Pages 1-24 January I973 PAYCAL Vol. 10 No. I January 1973 PROCEED I N GS THE SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY OF Officers of The Society for Analytical Chemistry and the Analytical Division of The Chemical Society C.Whalley President Hon. Secretary W. H. C. Shaw Hon. Treasurer Hon. Assistant Secretaries G. W. C. Milner D. I. Coomber O.B.E.; D. W. Wilson Secretory Miss P. E. Hutchinson 9/10 SAVILE ROW LONDON WIX IAF Telephone 01-734 9864 Editor J. B. Attrill Assistant Editor P. C. Weston Proceedings is published by The Society for Analytical Chemistry. Members’ subscriptions must be sent t o The Chemical Society. Nonmembers can be supplied with Proceedings only as part of a combined subscription with The Analyst and Analytical Abstracts. 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 30p post free. Remittances MUST accompany orders. 0 The Society for Analytical Chemistry INDEXES 1972 The Index to Volume 9 of Proceedings and the Index to Volume 97 of The Analyst will be distributed to Members and to Subscribers in February. The Index to Volume 23 of Analytical Abstracts covering July to December 1972 is expected to be ready for distribution during April and copies will automatically be sent to Members and Subscribers entitled to receive them.

ISSN:0037-9697    

DOI:10.1039/SA97310FX001

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

2 REPORTS OF MEETINGS _Proc. SOC. Analyt. Chem. Reports of Meetings NORTH WEST REGION Ax Ordinary Meeting of the Region was held a t 2.30 p.m. on U‘ednesday December 13th 1972 at the Universities of Liverpool and Manchester Research Reactor Centre Risley. The Chair was taken by the Chairman of the Region JIr. G. F. Longman. A short illustrated talk was given on the broad principles and applications of activation analysis by G. R. Gilmore. During the tour of the Centre a brief demonstration of the activation analysis spectrometry system was given. SCOTTISH REGION THE thirty-eighth Annual General Meeting of the Region was held at 6 p.m. on Friday November 3rd 1972 a t the University of Strathclyde Glasgow C.1. The Chair was taken by the Chairman of the Region Dr. J. A. Hunter. The following office bearers were elected for the forthcoming year Chairman-Mr.\V. Dunnet. Vice-Chairnzaiz-Dr. J. 11. Ottaway. Honorary Secretary and Treasurer-Dr. J. E. JYhitley Scottish Universities Research and Reactor Centre East Kilbride Glasgow G75 OQU. Xembers of Cowmzttee-Dr. D. Barnes Miss S. M. Brown Alr. N. G. Cadzow Mr. B. E. Pearce Nr. P. J Stevens and Miss RI. R. Taylor. The Annual General Meeting was followed by an Ordinary Meeting of the Region a t which the Chair was taken by the new Chairman 1Ir. IV. Dunnet. X lecture on “Industry and Forensic Science” was given by J. K. RIcLellan. A JOINT Yeeting of the Region with the Glasgow and \Vest of Scotland Section of the CS and the Andersonian Chemical Society was held a t 4 p.m. on Thursday December 7th 1972 a t the University of Strathclyde Glasgow C .l . The Chair was taken by the President of the Andersonian Chemical Society RIr. A. Soutar. A lecture on “Atomic Spectroscopy for Pollution Control” was given by Professor T. S. West. 1fr. J. S. Foster and Rlr. A. F. \Villiams were re-appointed as Honorary Auditors. WESTERN REGION A JOINT Meeting of the Region with the South East byales Section of the CS was held a t i p.m. on Friday December 8th 1972 in the Cniversity Staff Dining Club Park Place Cardiff. The Chair was taken by the Chairman of the Q’estern Region Dr. J. D. R. Thomas. A lecture on “Some Views on the Cost Effectiveness of Analytical Research” was given by C. Whalley. MIDLANDS REGION THE eighteenth Annual General Meeting of the Region was held at 6 p.m. on Tuesday November 14th 1972 in the Haworth Building The University Birmingham 15.The Chair was taken by the Chairman of the Region Mr. P. G. It’. Cobb. The following office bearers were elected for the forthconiing year Chairman-Mr. S. Greenfield. Vice- Clznirman-Dr. D. Thorburn Burns. Honorary Secretary-Dr. a. G. Fogg Department of Chemistry University of Technology Loughborough Leics. LE11 3TU. Hoizorary Treasurer-Dr. A. Townshend. Members of Committee-Mr. H. E. Brookes Dr. V. J. Jennings Dr. A. h1. G. Macdonald Mr. D. M. Peake Dr. D. N. Raine and Nr. J. E. W. Tillman. Mr. R. Holmes and Mr. H. Pugh were appointed as Honorary Auditors. The Annual General Meeting was followed by an Ordinary Meeting of the Region a t which the Chair was taken by the new Chairman Mr. S. Greenfield. A lecture on “Forensic Science” was given by P.G. W. Cobb. January 19731 REPORTS OF JIEETISGS 3 MIDLAKDS REGION AND SPECIAL TECHNIQUES GROUP A JOINT Meeting of the Midlands Region and the Special Techniques Group was held a t 6.30 p.m. on Tuesday December 12th 1972 a t the Haworth Building The University Birming- ham 15. The Chair was taken by the Chairman of both Region and Group Mr. S. Greenfield. A lecture on “Ion-beam Thin-foil Spectroscopy” was given by I. Martinson. JIICROCHEMICAL METHODS GROUP THE twenty-ninth Annual General Meeting of the Group mas held at 7 p.m. on Monday November 27th 1972 in College Block Imperial College London S.W.7. The Chair was taken by the Chairman of the Group Mr. S. Bance. The following office bearers were elected for the forthcoming year Chairma%-Dr. D. A. Pantony. Vice-Chairman-Xr.S. Bance. Honorary Secretary-Mr. P. R. \V. Baker Chemical Research Laboratory The IVellcome Research Laboratories Langley Court Beckenham Kent BR3 3BS. Hoizorary Treaswer- Ilk. ,4. C. Thomas. Mernbers of Committee- RIr. E. Bishop blrs. D. Butterworth Mr. R. Goulden Mr. C. A. Johnson bfr. A. T. Masters and llr. B. T. Saunderson. RIr. H. Childs and Mr. H. I. Shalgosky were re-appointed as Honorary Auditors. The Annual General Meeting was followed by a Cheese and Wine Party jointly with the Radiochemical Methods and Education and Training Groups. Honorary Assistant Secretary-Mr. R. Sawyer. SPECIAL TECHNIQUES GROUP THE twenty-eighth Annual General Meeting of the Group was held at 2.30 p.m. on Tuesday November 21st 1972 in College Block Imperial College London S.W.7. The Chair was taken by the Chairman of the Group Mr.S. Greenfield. The following office bearers were elected for the forthcoming year Chairman-Mr. S. Greenfield. Vzce-Chazrman-Dr. R. >I Dagnall. Honorary Secretary and Treasurer-llr. J. T. navies Research and Development Department Metal Box Co. Ltd. Twyford Abbey Road London N.\V.10. Members of Comwzzttee-Mr. B. B. Bach JIr. P. G. \V. Cobb Nr R. V. Hems Nr. D. C. M. Squirrell Dr. 11. J. Thompson and Dr. A. Townshend. Dr. G. Ill. S. Duff and A h . J. H. Glover were re-appointed as Honorary Auditors. The Annual General Meeting was followed by an Ordinary Meeting of the Group at which the subject was “Plasma Excitation in Spectrochemical Analysis” and the following papers were presented and discussed “The H.F. Plasma Torch,” by S. Greenfield P.B. Smith and H. JIcD. McGeachin; “The Microwave Plasma Torch,” by R. 11. Dagnall and R. L. Sharp; “The Plasma Jet,” by E. A. du Bois and R. Ilarriott. CHROMATOGRAPHY AND ELECTROPHORESIS GROUP THE eighth Annual General Meeting of the Group was held a t 2.30 p.m. on Wednesday Kovember 22nd 1972 at the Polytechnic of the South Bank Borough Road London S.E.1. The Chair was taken by the Chairman of the Group Dr. E. V. Truter. The following office bearers were elected for the forthcoming year Clzainnaiz-Dr. E. V. Truter. Vice-Chaiwmn- Mr. J. W. Murfin. Honorary Secretary and Treasurer-Nrs. D. Simpson Bakelite Xylonite Ltd. Research and Development Lawford Place hlanningtree Essex COll 2NA. Members of Committee-Mr. G. B. Crunip h‘lr. E. J. Gallacher Mr. E. S. Goodwin Dr. D. F. G. Pusey Dr.M. J. Sewell and Dr. J. D. R. Thomas. Dr. S. J. Purdy and Mr. J. S. Wragg were re-appointed as Honorary Auditors. The Annual General Meeting was followed by an Ordinary Meeting of the Group a t which the subject was “Polymer Characterisation by Chromatographic Means” and the following papers were presented and discussed “Isomerisation Problems in the Analysis of Some Polyester Resins,” by D. F. G. Pusey and W. A. Ledger; “The Application of Gel Permeation and Affinity Liquid Chromatography to the Analysis of Polybutadienes,” by R. J. J. Simkins and E. J. Gallacher; “Decomposition Products of Nylon,” by G. C. East C. J. Lupton and E. V. Truter. 4 REPORTS OF 3IEETIKGS -Pvoc. SUC. Analyt. C h t . THERMAL METHODS GROUP THE eighth Annual General Meeting of the Group was held a t 10 a.m.on Thursday Sovember 23rd 1972 at the Royal Astronomical Society Burlington House London lY.1. The Chair was taken by the Chairman of the Group Dr. J. H. Sharp. The following office bearers were elected for the forthcoming year Citazrwzan-Dr. J. H. Sharp. I’zcz-C~nznnniz-~Ir. K. E. J. Barrett. Honorary Secretary-Mr. C. J. Keattch Industrial and Laboratory Services P.O. Box 9 Lyme Regis Dorset. M e d w s of Committee-Dr. 11. C. Ball Mr. E. L. Charsley Dr. D. Dolhmore Dr. R. C. JIdckenzie Mr. R. E. iYaller and Dr. J. W. Youren. Dr. iY. Boardman and hlr. P. J. Haines mere re- appointed as Honorary Auditors. The Annual General Meeting was followed by an Ordinary Meeting of the Group a t which the subject was “Inorganic Applications of Thermal Analysis” and the following papers were presented and discussed “Thermal Decompositions in Inorganic Compounds,” by Professor D.W. A. Sharp; “The Thermal Decomposition of Manganese Oxy-salts and Manganese Oxide Transformations,” by K. H. Tonge; “Thermoanalytical Studies of Pyro- technic Jlixtures,” by F. S. Scanes; “The Thermal Decomposition of Some Double Carbonates,” by K. RI. JlcIntosh and J. H. Sharp; “Application of Thermal Analysis to X.T.C. Thermistors,” by E. D. Macklen; “Thermal Analysi- of Serpentine Asbestos and Related Ilinerals,” by L. F. JIonkman. Hoizornry Treasurer-Dr. A. A. Hodgson. AUTOMATIC METHODS GROUP THE seventh Annual General Meeting of the Group wa5 held at 2.30 p m . on Friday Koveinber 17th 1972 in College Block Imperial College London S.iV.7. The Chair was taken by the Chairman of the Group Dr.J. &I. Skinner. The following office bearers were elected for the forthcoming year Chairman-Dr. J. 11. Skinner. Vice-Clznzvnzatt-~~r. C. L. Denton. Honovary Secretary-Mr. R. Sawyer Laboratory of the Government Chemist Cornwall House Stamford Street London SE1 9NQ. Honorary Trenszwer-llr. F. Trowell. HOPZOYLZ~~ ,$sststnnt Secwtavy-Rlr. J. L. Martin. rFIewzbers of CovninIttee-Dr. K. Charlton Jlr. K. Cooper Dr. G. F. Reynolds Mr. D. C. )I. Squirrell 11r. J. Stevens and Mr K. H. IYall. Dr. J . E. Page and Mr. \Y. H. C. Sliaw were re-appointed at Honorary *Auditors. The Annual General Meeting was followed by a Joint Jleeting with the Electroanalytical Group a t which the Chair was taken by the Chairman of the Electroanalytical Group Dr. B. Fleet. lecture on “Enhancement of Chemical RIeasurement Techniques [-sing On-line Digital Computers” was given by Professor S.P. Perone. PARTICLE SIZE AXALPSIS GKOUP THE seventh Annual General Meeting of the Group was held at 2.30 p.m. on LYednesday Yovember 22nd 1972 in the Chemistry Department Chelsea College Xanreia Road London S.il’.3. The following office bearers were elected for the forthcoming year Ciznzwnan-Dr. h1. J. Groves. Vice-Chairmait-Dr. IT. Carr. Honovav! Secretary and Trtmurev-llr. 11. \V. G. Burt Building B9C5 A.V’.R.E. Aldermaston Berks. Hono~ary L4sszstant Sccrctar>~-Dr. N. G. Stanley-\Yood. Member of Cowznzitter-JIr. P. K. Kiff ilk. il’ G. King Dr. K. Marshall hIr. H. J. Scullion AIr. C. R. G. Treasure and Dr. R. \Vilson. Dr. T. Allen and A h . P. \Y Shallis were re-appointed as Honorary Auditors.The Annual General Meeting was followed by an Ordinary Meeting of the Group a t which the Chair was taken by the new Chairman Dr. hI. J. Groves. The subject of the meeting was “Applications of Particle Size Analysis to Pharmacy” and the following papers were presented and discussed “The Methods of Inspecting Intravenous Fluids for Particulate Contamination,” by 11. J. Groves; “Particle Size Analysis of Pharmaceutical Aerosols,” by J. H. Bell; “The Influence of Particle Size on the Formulation of Hard Gelatin Capsules,” by J. 31. Newton. The Chair was taken by the Vice-chairman of the Group Dr. RI J. Groves. January 19731 REPORTS OF MEETISGS 5 RADIOCHEMICAL METHODS GROUP THE sixth Annual General Rleeting of the Group was held a t 6.30 p.m. on Nonday November 27th 1972 in College Block Imperial College London S.W.7.The Chair was taken by the Chairman of the Group Dr. S. J. Lyle. The following office bearers were elected for the forthcoming year Chairman-Mr. J. W. 1lchIillan. Vice-Chairman-Dr. P. Johnson. Ho?$orary Secretary-Mr. &I. A. Crook Department of Chemistry and Polymer Technology Polytechnic of the South Bank Borough Road London S.E. 1. Honorary Treaswer-Dr. D. I. Coomber. Members of Committee-Dr. K. Boddy Dr. A. Dyer Dr. B. I$’. Fox and Mr. D. A. Ginger. Dr. F. J. Bryant and Dr. J F. C. Tyler were re-appointed as Honorary Auditors. The Annual General Meeting was followed by a Cheese and Wine Party jointly with the Microchemical Methods and Education and Training Groups. ELECTROANALYTICAL GROUP THE third Annual General Meeting of the Group was held a t 2.45 p.m.on Friday November 17th 1972 in College Block Imperial College London S.W.7. The Chair was taken by the Chairman of the Group Mr. J. V. Westwood. The following office bearers were elected for the forthcoming year Chairman-Dr. B. Fleet. Vice-Chairman-Dr. P. 0. Kane. Honorary Secretary-Dr. W. F. Smyth Department of Chemistry Chelsea College University of London Manresa Road London S.W.3. Honorary Treusztre?f-Dr. R. D. Jee. Members o j Committee-Dr. B. Birch Mr. A. Bottom Dr. J. Janata Dr. K. Torrance Dr. J. D. R. Thomas and Mr. J. V. Westwood. Mr. J. H. Glover and Dr. J. 11. Skinner were re-appointed as Honorary Auditors. The Annual General Meeting was followed by a Joint Meeting with the Automatic Methods Group a t which the Chair was taken by the Chairman of the Electroanalytical Group Dr.B. Fleet. A lecture on “Enhancement of Chemical Measurement Techniques Using On-line Digital Computers” was given by Professor S. P. Perone. EDUCATION AND TRAINING GROUP THE second Annual General Meeting of the Group was held a t 7.30 p.m. on IIonday Sovember 27th 1972 in College Block Imperial College London S.W.7. The Chair was taken by the Chairman of the Group Dr. W. J. Williams. The following office bearers were elected for the forthcoming year Chairman-Mr. J. K. Foreman. Vice-Chairfiza?t-Dr. J. B. Headridge. Honornry Secretary-Dr. h’. Crosby Laboratory of the Government Chemist Cornwall House Stamford Street London SEl 9NQ. Honorary Treasurer-Dr. W. J. 1i.illiams. Honorary Assistaut Secretary-Nr. IT. 11. Lewis. JIewbers of Cowunittee- Dr. D. Thorburn Burns Dr. J. H. Chapman Dr. J. 4 . W. Dalziel Dr. T. C. Downie Dr. L. C. Roselaar and Dr. J. G. Pritchard. RIr. D. Moore and Dr. A. Toivnsliend were re-appointed as Honorary Auditors. The Annual General Meeting was followed by a Cheese and \Vine Party jointly with the Microchemical Riethods and Radiochemical Methods Groups.

ISSN:0037-9697    

DOI:10.1039/SA9731000002

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Forthcoming Meetings-continued jrona back covey February Tuesday 20th LOXDOS Tuesday 20th COVENTRY Wednesday 2 1st NEWCASTLE Thursday 22nd CHESTER Friday 23rd hfANNINGTREE U’ednesday 28th LOXDOS Wednesday 28th LOUGH- BOROUGH SAC/AD organised by the SPECIAL TECHSIQUES GROUP on “Modern Develop- “Analytical Microwave Spectroscopy,” by Professor J . Sheridan. “The Microwave Plasma Detector (MPD) for Gas Chromatography,” by W. R. “Hadamard-transformation Spectrometry,” by J. A. Dicker Jun. Scientific Societies Lecture Theatre 23 Savile Row London W.l; 2.30 p.m. MIDLAXDS REGIOK. ‘%on-selective Reagents,” by M. J. Toogood and C. Watson. Lanchester KORTH EAST REGION and AUTOMATIC METHODS GROCP on “Future Trends in “Latest Techniques and Future Aspects of Auto Xnalysers,” by R.J. King. “JYhither Discrete Automatic Chemical Xnalysers ? ” by K. J . Mills. “Automatecl Techniques for the Analytical Chemist,” by Professor C. T. “Trends in Automatic X-ray Analysis,” by P. Hurley. “lutomatic Analysis with a Computerised Quontovac Emission Spectrometer,” “A Selective Detector for Gas Chromatography,” by A. Dawson. Chemistry Department The University Newcastle; 2 p.m. “Control of Pharmaceutical Products,” by A. G. Fishburn. Chester; 7.30 p.m. EAST ANGLIA REGIOK on “Plastics.” “Some Methods Used in the Analysis of Plastics Formulations,” by Diana “The Application of Gel Permeation and Affinity Liquid Chromatography to “Fluorescence and Phosphorescence Characteristics of Some Antioxidant and Cltraviolet Absorber Compounds Used as Additives to Polymers,” by G.F. Bakelite Xylonite Ltd. Research and Development Lawford Place Manning- tree Essex; 2.30 p.m. MICROCHEMICAL METHODS GROUP London Discussion Meeting. Discussion on “Non-aqueous Titrations,” introduced by D. C. Ill. Squirrell. Imperial College London S.TV.7; 6.30 p.m. ELECTROANALYTICAL GROUP on “Electrochemical Techniques for Oxygen “Electrochemical Membrane Sensors for Oxygen,” by I. Bergman. “Applications of Fuel Cell Electrodes for Oxygen and Related Analysis,” by “Electrodes for Ion-level Oxygen Measurement,” by M. Riley. “Oxygen Xeasurement Respirative Physiology,” by D. Parker. Chemistry Department University of Technology Loughborough; 2.30 p.m. ments in Spectroscopy.” McLean. Polytechnic Coventry; 6.30 p.m. Automated hnalysis ’ ’ Rhodes and R.E. Hone. by K. Liddle. h-ORTH WEST REGION. Simpson. the Analysis of Polybutadienes,” by E. J . Gallacher and R. J. J. Simkins. Kirkbright. Determination.” B. Fleet. SOCIETY FOR ASALYTICAL CHEMISTRY ANALYTICAL DIVISIOS CHEMICAL SOCIETY Forthcoming Meetings January Saturday 20th XORTH WEST REGION Annual General Meeting followed by the Address of the The University Salford; 2.30 p.m. SCOTTISH REGION jointly with the Edinburgh and South East of Scotland “Analysis and Archaeology,” by H. McKerrell. National Museum of Antiquities of Scotland Edinburgh; 5 p.m. Wednesday 24th NORTH EAST REGION Annual General Meeting. “An Assessment of the Analytical Techniques of Atomic Spectrometry,” by Teesside Polytechnic Borough Road nliddlesbrough ; 7 p.m. Wednesday 24th MICROCHEMICAL METHODS GROUP London Discussion Meeting.SALFORD Tuesday 23rd Retiring Chairman G. F. Longman. EDINBURGH Section of the CS. MIDDLES- BROUGH Professor T. S. West. LONDON Thursday 25th LONDON February Tuesday 6th SWANSEA Tuesday 13th SHEFFIELD Thursday 15th GLASGOW Friday 16th EXETER - Discussion on “Specifications for Reference Substances and Reagents ” intro- duced by E. Bishop. Imperial College London S.W.7 ; 6.30 p.m. SAC/XD Burns Night. Social evening for a film and slide show of “people and events” a t various Cocktail snacks and wine will be available a t a Conferences and Meetings. charge of L1 per person. 7.30 p.m. Senior Staff Common Room South Side Imperial College London S TY.7; WESTERN REGION joi,ntly witlz the South Wales (West) Section of the CS. “The Chemist a t Sea,” by Professor J.P. Riley. Chemistry Department University College Smansea ; 7 p.m. EDUCATION AND TRAIKINGROUP jointly with the Sheffield Metallurgical and Engineering Association on “The Training of Analytical Chemists for the Steel Industry.” Speakers to include J. Little. B.I.S.R.A. Hoyle Street Sheffield; 6.30 p.m. RADIOCHEMICAL METHODS GROUP and SCOTTISH REGION on “\Thole Body “Chemical Analysis of Cadavers and the ICRP Standard Man,” by Gwyneth “Body Composition Density Fat and Fat-free Mass,” by J. V. G. A. Durnin. “Body Potassium and Body Composition,” by L. Burkinshaw. “Kinetic Analysis and Isotope Dilution,” by P. Tothill. “Total Body in vivo Neutron Activation Analysis in Normal Subjects,” by S. B. Osborn. “Total Body Calcium and Sodium by in z h o Neutron Activation Analysis and Nitrogen by Pulsed Techniques,” by Professor J. H. Fremlin. “Simultaneous Measurement of Total Body Calcium Sodium Chlorine Phos- phorus and Nitrogen by in vivo Neutron Activation Analysis,” by I<. Boddy. Scottish Universities Research and Reactor C,entre East Kilbride Glasgow ; 9.30 p.m. \VESTERN REGION jointZy with the Peninsular Section of the CS. “The History of Analytical Chemistry,” by Professor R. Belcher. Sewman Building The IJniversity Exeter; 5.15 p.m. Analysis.” Parry Howes. [continued inside back coueY Printed by W Heffer & Sons Ltd Cambridge England

ISSN:0037-9697    

DOI:10.1039/SA97310BX003

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

6 LIQUID CHROMATOGRAPHY [Proc. Soc. Analyt. Citent. Liquid Chromatography The following is a summary of one of the papers presented a t a Meeting of the Midlands Region held on September 5th 1972 and reported in the October 1972 issue of Proceediizgs (p. 216). High-performance Liquid - Solid Chromatography BY K. AMOS (Esso Reseai,ch Ceiztve rlbingdon Berkshive OX13 GAEi CHROMATOGRAPHY is now well established as the most powerful analytical technique available for the separation and quantitative determination of complex mixtures. However while it took only 20 years from its initial conception to almost perfect gas chromatography liquid chromatography has proceeded in a series of fits and starts over the past 70 years. A quarter of a century elapsed from the time the Russian botanist Tswettl first showed us how to use the technique before Kuhn and Ledere? subsequently revived it during their studies on plant pigments.For the next 35 years no substantial progress was made in either the theory or technique of liquid chromatography in columns although the number of applications increased during this period. Arising from the theoretical plate concept of Martin and Syr~ge,~ gas chromatography emerged as a highly sophisticated and successful technique that allowed chromatographic theory to be developed further ; meanwhile limited improvements in liquid chromatography were obtained through the development of the bed layer techniques of paper and thin-layer chromatography. At the present time liquid chromatography is taking another leap forward.4 Much of the progress is due to the greater understanding of chromatographic theory and improved technique learnt from gas chromatography.Thin-layer chromatography has limitations because chromatographic conditions cannot be adequately controlled and therefore opti- mised. Quantitation by thin-layer chromatography is clumsy often inadequate and the technique cannot be automated. Gas - liquid chromatography is limited only by the requirement that the samples must be volatile a t the temperature at which they are to be separated. In contrast to gas chromatography in which the majority of work is carried out by partition chromatography adsorption partition ion exchange and gel exclusion are all widely used in liquid chromatog-aphy. As the apparatus technique and dynamics of the chromatographic process are similar in all four instances the remaining discussion will be confined to adsorption chromatography and in particular to the use of silica as the stationary phase.Although the lack of suitable detectors has carried much of the blame for the slow development of liquid chromatography the crucial factor lies in the construction of a high- performance column. No liquid chromatograph can give a better separation than that given by the column itself but it is vitally important to see that the performance of the column is not impaired by poor design of the ancillary equipment. By considering the factors that cause band spreading in a chromatographic column an expression for the plate height H of the following type is obtained- Fortunately dramatic progress was achieved in other directions. A- 7- Eddy Nolecular Resistance to diffusion diffusion mass transfer where X and y are packing factors d is the particle diameter and zt is the linear velocity of the mobile phase.-4s the molecular diffusion term is much lower than the others it can be seen that there is a conflict between high efficiencies (low values of H ) and fast analysis times (i.c. high January 19731 LIQUID CHROMATOGRAPHS 7 values of u). Although the equation for band spreading is much more complex than shown and contains several conflicting criteria it can be concluded that high-efficiency columns can be produced by packing long narrow columns with tiny regularly shaped particles covering only a small size range. \Ye pack 1-m lengths of columns of 2 to 4 mm i.d. by adding sufficient dry (4 per cent. water deactivated) silica a t a time to fill a 2-cm length of column.After each addition the column is bounced on the floor and tapped with a metallic rod about a dozen times and the bed consolidated by light tamping. Xdsorbents with particle size greater than 20 pm average diameter are fairly easy to pack but below 20 pm packing becomes increasingly difficult. Longer columns are prepared by coupling 1-m lengths together with short lengths of 1'16 inch diameter tubing filled with Ballotini beads. Xt first attempts were made5 to pack columns with a thin-layer Chromatographic grade of silica gel. Fig. 1 shows that fractions of narrow particle size ranges sieved from a wider particle size range of gel produce more efficient columns the H value for a given mobile phase velocity being reduced by an order of magnitude.A compromise must therefore be sought. Fig. 1. Particle sizes 1 unsieved (thin-layer chromatographic grade); 2 30 to 75 pm; and 3 20 t o 30 pm Effect of particle size range on band spreading. Similar gels are now commercially available in a series of narrow particle size ranges and Fig. 2 shows quite clearly the effect of reducing the average particle diameter on column performance.6 It can be seen that as the particle size is reduced the columns become not only more efficient but also less dependent on flow-rate because of decreasing resistance to mass transfer. It is difficult to pack columns with particles whose diameters are less than 20 pm but once this technique is mastered,' by working a t high pressures i.e. in excess of 2000 p.s.i.g. per metre length of column it should be possible to carry out fast analyses on high-efficiency columns packed with porous silicas having a high sample capacity.A major factor causing band spreading is the resistance to mass transfer. In an attempt to reduce this resistance and to facilitate regular packing a number of stationary phases are now available that consist of solid spherical cores coated with a porous surface of con- trolled thickness and pore size.8 Columns packed with these materials have high efficiencies (i.e. less than 1.0 mm) which are little affected by flom-rate and so fast analyses can be carried out without impairing column performance. A major disadvantage is that they have a very low sample capacity which puts a strain on detector sensitivity and the further analysis that can be carried out on isolated components.The surface area of Corasil for example is 7 ni2 g-l vrhile that of a porous silica of similar diameter is 300 m2 g-l. In practice the sample capacity of coated beads is two orders of magnitude less than that of the porous gels. 8 2.0 E E x . 1.0 LIQUID CHROMATOGRAPHY [Proc. SOC. Astalyt. Chenz. - - v’ / /3 I I 0.1 0 2 0.3 p/cm s-’ Fig. 2. different velocities of the mobile phase. phase n-heptane; and column 1 m x 4.65 mm. t o 53 pm; 2 21 t o 39 pm; and 3 16 t o 26 pm 0 Effect of particle size of Merckosorb SI 60 on plate height a t Solute naphthalene; mobile Particle sizes 1 36 As most commercial chromatographs available in the U.K. were unnecessarily sophisti- cated and their cost excessively high a simple but effective chromatograph was constructed from individual unit^.^^^ The mobile phase chosen by preliminary thin-layer chromato- graphic experiments is gravity-fed to an Orlita pump which is capable of delivering up to 10.6 ml min-l against a pressure of 4000 p.s.i.g.Nearly pulse-free operation is obtained by inclusion of a Bourdon-type gauge between the pump and the sample injection port. De- gassing of solvents has been found to be unnecessary. Sample injection is carried out with a microsyringe through a PTFE-coated septum retained by a nut through which a hole is drilled that is just large enough to admit the syringe needle which deposits the sample into a layer of glass beads. The sample is rapidly swept into the upper layer of the adsorbent by the mobile phase where it is concentrated initially as a sharp band.With this device. a septum can withstand up to about twenty injections under an inlet pressure of 700 p.s.i.g. before it requires changing. Above this pressure flow is stopped before sample injection. Because liquids are virtually incompressible the original flow-rate is rapidly restored when the pump is re-started. Solute detection is by a Waters K4 differential refractoineter or a Perkin-Elmer Model 402 ultraviolet spectrophotometer equipped with a 5O-pl flow-through cell. Column - detector connections consist of short lengths of U16-inch tubing to minimise band spreading. High-performance liquid - solid adsorption chromatography is now being applied routinely to the analysis of a wide range of petroleum samples involving either trapping out unknown compounds for spectroscopic identification or for routine quantitative analysis with a precision of 2 per cent. of the amount present. REFERENCES 1. 3. 3. 4. 5. 6. 7. 8. Tswett &I, PYOC. Warsaw Sac. Nat. Sci. Bid. Sect. 1903 14. Kuhn R. and Lederer E. Bev. dt. chenz. Ges. 1931 64 1349. Martin A. J. P. and Synge R. L. hI. Biochern. I, 1941 35 91 and 1358. Perry S. G. Amos R. and Brewer P. I. “Practical Liquid Chromatography,” Plenum Press Stewart H. K. >I. Amos R. and Perry S. G. J Chrowzat. 1968 38 209. Amos R. “Proceedings of 9th International Symposium on Chromatography Rlontreux 1952,” hIajors R. E. Analyt. Ckern. 1972 44 1722. Kirkland J . J. Editor “Modern Practice of Liquid Chromatography,” Wiley-Interscience Sew New York 1952. Applied Science Publishers Ltd. London in the press. York 1971.

ISSN:0037-9697    

DOI:10.1039/SA9731000006

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

January 19731 ORIGISAL PAPERS IN PHXRMACECTICAL ANALTSIS Original Papers in Pharmaceutical Analysis 9 The following are summaries of three of the papers presented a t a Xeeting of the Joint Pharmaceutical Analysis Group held on June 8th 1972. Polarography as a Method of Quality Control in the Assay of Selected Pharmaceutical Products BY W. FRANKLIN S~II’TH (Cheniistvy Depavtment Chelsea College University of Londo+i 41anvesa Road L o d o n S. LV.3) -1 S U R V E ~ of the literature relating to the polarographic assay of compounds of pharma- ceutical importance will reveal the frequency of use of the technique in the 1980s with a rapid decline in the following decade. Perusal of more recent literature reveals however a renewal of interest in the applicability of polarography not only to formulation analysis but particularly to low-level monitoring of certain drugs and their metabolites in body fluids.The usefulness of polarography in quality control hitherto relatively unappreciated is illustrated by the following facts. 1 . Nany active constituents of formulations in contrast to the other ingredients are electroactive and can be oxidised or reduced under polarographic conditions e.g. compounds containing functional groups such as thiol azoniethine (which as well as existing isolated in a ring system can be formed by enolisation of carbonyl or thiocarbonyl functions in the x-position to the nitrogen atom) carbonyl thiocarbonyl and various valency states of nitrogen such as nitro and X-oxide. The method possesses an appropriate selectivity that is particularly important in tlie differentiation of mixtures when the active constituents are electroactive.An elegant example of this appeared recent1y.h the literature with the simultaneous determination of vitamins B and B and Niacinamide in a multi-vitamin preparation by cathode-ray polaro- graphy.l This selectivity can also be used to determine the degree of decomposition in those products where the breakdown product of the active material is reduced a t a different potential. 3. The method designed for the selected pharmaceuticals mentioned below is rapid and does not involve any separation step. The active constituent is dissolved out of the formulation into a suitable solvent medium (a hydrochloride can be quickly dissolved in water - methanol and many others in an aprotic solvent such as dimethyl formamide acetonitrile or dimethyl sulphoxide) while being ground up in a mortar.h n aliquot of the mixture is then sampled dissolved in an appropriate medium which may be a traditional aqueous supporting electrolyte or the aprotic solvent - tetraalkylammonium salt and the current - potential curve recorded after deaeration. By reference to a pre-determined calibration graph or by the standard addition method a single or multi-tablet assay can be carried out in a minimum of 10 minutes with an error of 2 to 3 per cent. well within the limits allowed by the British Pharmacopoeia or National Formulary. The ability to carry out polarographic measurements in an entirely non-aqueous medium increases the number of preparations that can be assayed by this means. 5J’- Disubstituted barbiturates such as for example phenobarbital are electroinactive under aqueous conditions but are reduced in a different way in aprotic media resulting in well defined reversible waves.A wide variety of electroactive compounds of pharmaceutical importance have been subjected to polarographic study and all have given waves suitable for analytical purposes. This includes hypnotics and tranquillisers such as the barbiturates mentioned above 1,4-benzodiazepines (nitrazepam medazepam chlordiazepoxide diazepam flurazepam oxazepam and lorazepam) and quinazolines (methaqualone). Further additions to the list are intravenous anaesthetics such as thiobarbiturates antibiotics such as the tetracyclines (tetracycline hydrochloride oxytetracycline chlortetracycline) and some steroid hormones such as testosterone.Very common reducible functional groups encountered in this series are azomethine and carbonyl two which seem to appear frequently in molecules of biological significance. Many of these compounds possess non-aromatic heterocyclic ring systems and their behaviour parallels that of other similar organic substances being modified only by 2 . 4. 10 [Proc. SOC. -4 ualyt. Chevz. the presence of the heterocyclic ring. In addition to this concept there is one additional factor that occurs with most heterocycles-their adsorbability on the mercury drop either of the depolariser itself or of reaction intermediates or products This can complicate the wave pattern in aqueous media in the concentration range to 10-~ RI (frequently adsorption effects are absent in an entirely aprotic medium) but is an added advantage a t the lower concentrations encountered in body fluid analysis.This has recently been exploited2 by polarography carried out directly in blood serum containing “spiked” benzo- diazepines and obtaining measurable adsorption currents even in the presence of the other biological constituents. The method of approach used to ascertain ideal conditions for the assay of a formulation involves the determination of the polarographic behaviour of the active constituent(s) in the pH range 2 to 12 in Britton-Robinson buffers. Non-aqueous niedia are used only when no or badly defined waves are observed in aqueous solutions. The limiting current is plotted against pH and the pH region where the best defined and/or largest wave exists is chosen as the medium for the assay.Graphs are constructed of the limiting current iwsus concentra- tion in the range M a t this optimum pH and linearity is generally observed. The formulation is ground down dissolved in an appropriate solvent medium an aliquot diluted with buffer and the current - potential curve recorded. Small amounts of non- aqueous solvent (10 to 20 per cent.) in the sample solution rarely affect the height or linearity of the calibration graph determined in completely aqueous media. Several of the benzo- diazepines and tetracyclines have been tested by the outlined method and a good correlation between the expected content and the recovered content of the formulation has been found. ,4 suitable cell system has been designed that can be used by the quality control analyst in conjunction with standard polarographic equipment so that the criteria of selectivity simplicity and speed of assay are satisfied as far as possible.Work is in progress to operate this on a semi-automatic basis. ORIGINAL PAPERS IN PHARMACEUTICAL ANALYSIS to REFERENCES 1. 2. Schertel JI. E. and Sheppard A. J . J . Pharnz. Sci. 1971 60 1070. Halvorsen S. and Jacobsen E. A mlyticn Chinz. <4cta 1972 59 137. An Automated Method for the Determination of Thiabendazole BY T. D. \VHITE (Quality Copztrol Depai,tment. Mevck Shavp 6- Dohwic LZ‘iiiitrd Hoddesdon Hevtfovdsiiire) THE official A.O.A.C. method for determination of thiabendazole [2-(4‘-thiazolyl)benz- imidazole a pharmaceutical and veterinary anthelmintic and agricultural fungicide in animal feedstuffs was described by Szalk~wski.l-~ This method has been adapted as an automated method using Technicon AutoAnalyzer I equipment.This colorimetric method is less prone to interference than ultraviolet spectrophotometric measurement and requires less complex preparation than fluorimetric measurement. Other compounds that contain the thiazole ring interfere. A flow diagram is shown in Fig. 1. Finely ground feedstuff is shaken with ethyl acetate and the filtered extract re-extracted with 0.1 s hydrochloric acid for presentation to the system a t a nominal concentration of 5 pg ml-l. In the system the acidic solution of thiabendazole is reduced with a 0.3 per cent. slurry of zinc dust in glycerine and the products are coupled with a 0.17 per cent. solution of P-phenylenediamine dihydrochloride in 2 s sulphuric acid and a 15 per cent.solution of ammonium iron(II1) sulphate in 0.1 x sulphuric acid forming a blue complex whose absorbance is measured at 610 nm in a 15-mm flow cell During reduction the use of glass transmission tubing and the minimisation of mixing reduces aggregation of the zinc particles which is deleterious to consistent results. Complete reduction of thiabendazole concentrations to a t least 10pg ml-1 is achieved. Excess of zinc is removed by filtration through a glass-wool plug after the reduction stage. Reduction is carried out in an 80-foot glass delay coil. January 19731 ORIGINAL PAPERS IN PHARMACEUTICAL ASALYSIS 11 Owing to the high viscosity of the stream the normal polythene capillary connection between the colorirneter de-bubbler and the flow cell is replaced with standard transmission tubing.The system is calibrated by using thiabendazole standard solutions a t 2 4 6 and 8 pg ml-l and samples are analysed a t the rate of twelve per hour ( 2 minutes sampling and 3 minutes wash interval). Resolution is 0.1 pg ml-l and the coefficient of variation of ten assays of a single solution is 1.2 per cent. I 2.5 ~ 0 . 1 N HCI Sample 2.0 Air Resarnple Amine reagent 0.6 1.6 - - Iron( I I I) reagent Waste 4 - 7 Recorder Colorimeter 15-rnrn flow cell 610 nrn Fig. 1. Flow diagram 4 range of different commercial feed samples both unmedicated and containing other additives mixed with thiabendazole gave recoveries ranging from 95 to 100 per cent. at a 1 per cent. medication level. The original work on the manual method indicating low levels of interference was supported.For most formulations of thiabendazole ultraviolet spectrophotometric methods are available so that while of general applicability this method is likely to be mast useful for medicated feeds and possibly for the assay of residues in fruit currently involving a manual multiple-extraction procedure followed by fluorescence measurements. The manual colorimetric method is sensitive to changes in conditions and rigid adherence to the specified procedures is essential for accurate and reproducible results.2 The use of the AutoAnalyzer ensures uniformity reduces operztor bias and leads to an increased rate of sample processing although it is relatively slow for an automated chemical assay. REFERENCES 1. 2. 3. Szalkowski C. R. J - 4 s ~ . O f l . Agric. Chem. 1964 47 236 Szalkowski C .R. and Kanora J . I b i d . 19G5 48 288. Szalkowski C . R. I b i d . 1966 49 312. Permittivity Measurements Applied to Aqueous Solutions BY P. I. HARRISOP; (St Mary’s Hosfiital Pvncd Street London W.2) l l . 4 ~ 1 ~ medical and pharmaceutical techniques can benefit from analytical methods that can be incorporated into “in-line’’ systems. Ideally there should be no direct contact between the solution and the measuring apparatus. This was one of the criteria that stimulated the work outlined below. Permittivity (dielectric constant) is a measure of the electric dissymmetry of a dipole. A polar molecule placed between the plates of a charged condenser will rotate to align itself 12 ORIGINAL PAPERS IP; PHARMACEUTICAL XSALPSIS [Proc. SOC. Analyt. Clzenz. with the electric field.If the frequency is increased a region is reached when rotational drag and inertia limit complete alignment. D‘hen the frequency reaches the “microwave region,” it will often exceed the rotational frequency of the molecule. In the visible region only electrons can move sufficiently rapidly to be influenced by the field In addition to being frequency dependent (exhibiting dispersion) the permittivity of a system of molecules may be expected to change under other conditions that alter the freedom of movement of the molecules or their chemical nature for example pressure temperature solx7ent interaction viscosity and pH. This latter example in an extreme form may produce changes in the structure of the molecule (in the case of zwitterions). The capacitance of a condenser is a function of the permittivity of the molecular system between the plates of a condenser (i.e.the dielectric). In an alternating field energy may be dissipated. The permittivity of water (liquid state) decreases in the region of 10 000 NHz. At visible frequencies permittivity approximates to the square of the refractive index for most polar liquids. Bernal and Fowler1 suggested three possible structures for water a tridyinite-like structure for ice a quartz-like structure up to 200 ‘C and a close-packed ammonia structure at higher temperatures. Pauling2 proposed a pentagonal dodecahedra1 hydrate around a “guest” water molecule and based a general theory of anaesthesia on the formation of such hydrates in the cerebro-spinal fluid. The effects of the addition of electrolytes to water are explained in terms of whether or not the ions in question fit into the interstitial spaces and cavities and how much of their presence alters the lattice.Frank and \Ven3 postulated that hydrogen bonds would be continually forming and breaking giving groups of molecules with very brief half-lives. Drost-Hansen4 has produced evidence to show that many parameters including density specific heat viscosity permittivity and refractive index show anomalies at certain tempera- tures. To verify this measurements were made on water at 500 NHz and the temperature raised from 0 to 55 “C which is equivalent to lowering the frequency. The results showed a peak of dielectric loss a t about 40 “C which could be due to an alteration in water structure. The water was distilled sterilised and finally filtered into the cell through a 0.22-pm membrane filter to minimise spurious results due to micro-organisms.When a cation is added to water electrostriction occurs the water molecule crowding about the ion resulting in a smaller molar volume of water in the neighbourhood of the ion. As the concentration of the electrolyte is increased the various zones with differing degrees of order will successively overlap giving rise to the reversal of certain solution properties as observed by Good.5 An increase in pressure breaks up the local water structure near ions stripping away their hydration atmospheres and reducing their radii. An extreme case is that of a simple dehydrated ion moving through a non-associated medium. The plates of a condenser are effectively electrodes and a t low frequencies in particular are subject to electrode polarisation and unless four electrode cells or special switching bridges are used spurious results will be obtained.\Vhile Ermakov‘j has made conductance measurements in the 50 MHz region to differentiate between different ions it seems unlikely that this will form a basis for quantitative analysis. Measurements of conductivity and permittivity in this region can however be made without contact between the solution under test and the measuring electrodes. For 1 1 electrolytes conductivity plays a part up to about 2000 NHz but a t 1000 JIHz it is significantly concentration dependent. The 2 2 electrolytes show an unsymmetrical double dispersion of permittivity similar to the amino-acids. The lower frequency dispersion has been attributed to the relaxation of ion pairs.Studies of the health risks due to microwaves from radar and other equipment involve a knowledge of the permittivity and dielectric loss of tissues. lleasurements on niicro- organisms have permitted the calculation of their membrane thickness. Permittivity measurements are now being used in medicine to study the relationship between heart disease and abnormal lipoprotein^.^ The degree of hydration is sensitive to the variation in the shape of the lipoprotein molecules and this is the basis of a study of the relationships of abnormal lipoproteins associated with hyperbetalipoproteinaemia for these lipoproteins tend to be more strongly hydrated. This is shown as dielectric loss which is related to specific conductance. The permittivity of an amino-acid falls between 10 and 1000 RIHz.Many different structures probably exist simultaneously. January 19731 PARTICLE SIZE ANALYSIS 13 In addition to estimating from permittivity measurements the moisture content of powders the droplet size of water-in-oil emulsions can also be found. X further use is in the study of molecular behaviour. If functional groups are free t o rotate they will usually show a separate dispersion a t higher frequencies. This work was carried out in the Department of Pharmacy Chelsea College University of London Nanresa Road London S.W.3. The author acknowledges the assistance given by Professor Jonscher Department of Physics Chelsea College. REFEREXCES 1. 2 . 3 . 4. 5 . 6. 7 . Bernal J . D. and Fowler R. H. ,I. Chem. Plzys. 1933 1 515 Pauling L. Science 3-.1’. 1961 134 15 Frank H. S. and \$:en 1s’. Y . Discuss. Favadu-y Soc. 1955 21 133. Drost-Hansen W. Adv. Clzem. Sev. 1967 67 i 0 . Good W. E’lectvochiun. Acta 1964 9 203. Ermakov V. I. Sniirnov K. I. and Zagorets P. O. Russ. J Pizys. Chef??. 1963 37 280 Grant E. H. Sheppard K. J . Mills G. L. and Slack J . Lancet 1972 i 1159.

ISSN:0037-9697    

DOI:10.1039/SA9731000009

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

January 19731 PARTICLE SIZE ANALYSIS 13 Particle Size Analysis The following are summaries of the two papers presented a t a meeting of the Particle Size =Inalysis Group held on March lst 1972 and reported in the April issue of Proceedi?zgs (11. 7 8 ) . A Suggestion for the Exact Determination of Particle Size and Shape BY H. 11. SUTTOK ASD N. BTXDALLI (Wavren Spvzng Laborntoiy Stet enage He? tjovdshwe) PRIMARY Standards for the absolute measurement of particle size and shape are difficult to define. In practice particles are assessed by Secondary Standards such as sieving sediment- ation permeability adsorption light scattering and Coulter counting whereas the Primary Standards which can be obtained only by direct measurement on the particle image require a prohibitive amount of labour unless automatic scanning devices are available.DEFISITIONS- a point in space. or in three dimensions as where 4 is the azimuthal angular co-ordinate. be expanded as a Fourier series1- The size or shape of a particle is defined as the locus of points lying on its surface about In two dimensions this can be expressed in polar co-ordinates as * . .. .. . * (1) Y = r(0) a . . . . . y = r(@,4) .. . . .. .. . * I . (2) ,4t present only the two-dimensional case will be considered. The function r ( 0 ) can m r(0) = a + 2 (a cos 120 + b sin 120) . . .. .. * (3) n=l The coefficients ao a, a2,. . . . . . . . and b, b2,. . . . . . . . can be calculated and the parameters conveniently represent the size and shape of the particle represented by r(0). It can be shown that if a point in the particle is used as the origin such that a and b are identically zero then in a quantitative way the n = 2 terms describe the “elongation” of 14 PARTICLE SIZE ANALYSIS CProc.SOL. Analyf. Chew. the particle. The n = 3 terms are large if the particle has a “triangular” appearance (strictly if it has apexes separated by 2 ~ / 3 radians) the u = 4 terms are large for a “square” appearance and so on. The relative proportions of a and b determine the orientation of the particle relative to 0 = 0. In fact equation (3) can be written as y ( e ) = a +- C cos (ne + En) . . .. .. ‘ (4) 2 n = 2 where Cn2 = an2 + bn2 and En = arctan (-Cn/bn). If the zero is chosen so that E = 0 then the convention is rendered unique by the criterion I E I <n/3 because the n = 2 terms have a two-fold symmetry.The parameter a is the mean length of all the radii taken since i The other parameters are given by and a = - s2 Y cos no d8 x 0 0 .. .. * * ( 6 ) .. . . .. .. .. .. . . * * ( 7 ) .. 0 where M = 1 2 3 . . . . . . . . . etc. The coefficient a. can be taken as a size parameter while the others a and b,, are shape parameters. However this is not absolute; for example a diameter defined in terms of area immediately involves coefficients other than a, thus showing the explicit influence of size on shape. The “size” and “shape” of a particle are thus both logically and mathema- tically inseparable since the exact geometry can only be expressed in terms of all the Fourier coefficients. USE OF COXPUTERS- A computer program has been written to evaluate particle size and shape in terms of Fourier series.The program can process a digitised form of data of the kind which might be obtained from an automatic scanning microscope or a flying spot microdensitometer. Initially the data are scanned and the positions of points on the perimeter of particles are stored in the computer in a main storage array. I t is assumed that the original scanning instrument scans the specimen from left to right registering respectively zeros outside and units inside the particle profiles in the form of a grid. Preliminary rectangular co-ordinates are initially taken to cover the total scan area. These Cartesian co-ordinates of grid points on the perimeters of the particles are stored in the computer. The data [in a form similar to Fig. 1 (a) are scanned row by row left t o right starting from the top row of the data grid.Thus K and K [Fig. l,(b)] will be detected as two points on the outline of a particle in row R. The program incorporates a procedure for determining if K and K are perimeter points of a new particle that has not been scanned or of a particle that already has perimeter points in the store. The process of scanning and storing co-ordinates continues until all the data have been scanned. If the storage limit of the computer is reached the scanning of data stops and the Fourier parameters of each particle are calculated. Scanning of the data is then resumed because the data in the store are now redundant and can be overwritten. January 19731 PARTICLE SIZE ANALYSIS 15 Thus from the stored co-ordinates each particle is identified in turn and computations performed on the particle.The centroid of the particle is first calculated from x = - Xi and y = - Y i where 72 is the total number of scan points in a particle and X and Y refer to the preliminarj. Cartesian co-ordinate system. Then with the centroid as the origin the polar co-ordinates of the perimeter of the particle are evaluated. The radii of these points are interpolated a t uniform angle intervals in preparation for the calculation of Fourier parameters by \T'hittaker and Kobinson's method where the integrations in equations (ti) (6) and (7) are performed by using the trapezoidal rule. The parameters of each particle are computed before the com- putation of the next particle begins. - n lls 3 = 1 "fl. l2 a = 1 ! '*5 10 15 20 25 30 <5 Y 4 5- 10- 15- 20- 251 I 30.35; I 40. 45 50- 55- 60- 65; 75 I! 0 x- Y 4 R -1 R Fig. 1 ( a ) Test data processed by computer; and ( b ) scanning of data for particle end-point5 I< and K The Fourier series method for particle shape determination cannot deal with particles which have more than one value of r for any value of 8. The present computerised method cannot deal with particles that are orientated in such a way that the scan line crosses and re- crosses the particle outline (see Fig. 2). However as well as the advantages of identification of shape features in terms of large values of parameters mentioned earlier the whole of a scanned particle can be reconstructed by using the stored data (Fig. 3). 16 PARTICLE SIZE .4NALYSIS [Proc. Soc. Afzaljd. Chewi. nth row ( a ) (bi Fig. 2 (u) Re-entrant particle shape and ( b ) particle scanned as two separate particles in first row of scan In principle the Fourier coefficients can be used separately in any ad hoc correlation.For example in industrial quality control it may be desirable to have spherical particles and upper limits on the ratios @,/a and b,/a can be set. For elongated particles the ratios bz/aq and cgfao should be large compared with the other coefficients. Furthermore it is possible to make use of computers in simulating random packing of a collection of particles of known size or shape Similarly the tensile strength of a computer-generated compact can be determined by another averaging process that allows for the nature of the inter- particle forces. The number of parameters calculated for each particle does not substantially affect the compu- tation time.The computation time can be reduced by reducing the number of interpol- ations. For example if only two parameters are required for each particle ten interpol- ations would be sufficient. The computation time depends mainly on the amount of data being analysed. using parameters > O la0 > O 04ao > O 03ao 32 -016 a2 -016 61 - 0 0 3 a4 -010 a4 -0.10 a2 -016 a7 - 0 0 5 a9 -0 0 4 all -0 03 a7 - 0 0 5 a3 - 0 0 3 5 a9 - 0 0 4 63 - 0 0 3 611 -0 03 ( d ) Parameters (e) First 8 ( f ) First 22 (g) Actual shape > O 03ao parameters parameters of particle from first 14 61 - 0 0 3 h3 -0.03 67 -0.03 a3 -0.035 a7 - 0 0 5 Fig. 3. Reconstruction of particle shapes from Fourier para- meters with the Hewlett-Packard calculator/plotter January 19731 PARTICLE SIZE ATi-4LYSIS 17 The first part of the program i.e.scanning and storing can be put to a variety of other uses. For example by setting threshold levels to the intensity values to be processed different coloured areas of the specimen can be selectively analysed. Hence the program can be applied in biological work metallurgy and mineralogy. Finally to obtain data for three-dimensional particles Y(f?,q5) a sample of particles could be set in an appropriate resin and sectioned with a moving microtome although this would be difficult with hard or fine particles. The r(6) data and the thickness of the sections could then be converted to the r(B,+) form by computer. The corresponding Fourier series could be evaluated if required. Arrangements can be made for the computer program described in this paper to be made available.REFERENCES 1. 2. Cheng D C. H. and Sutton H. AT. S a t u r e (Plzyszcal Sczence) 1971 232 S o . 35 192. LVhittaker E. T. and Robinson G. "The Calculus of Observation Blackie London 1946 266; pp. The Effect of Particle Size on the Tensile Strength of Powders BY D. C.-H. CHENG (Warren Spring Laboratwy Stevenage Hevifoovdsltzvr) THIS note outlines a theory which relates the tensile strength of a compact of powders or granular material to the particle-size distribution. Details of the theory and experimental verification have been discussed elsewhere,l but some new modifications are presented here. The theory is based on the assumption that in a powder compact individual particles are packed against each other in a more or less random fashion.On average each particle is in contact with a number (the co-ordination number c) of other particles. The co-ordination number depends on the density of the compact p by the relationship .. . I .. * (1) .. 3 C = 1 - PIPS where p s is the density of the solids. When the compact is split under tension a number of pairs of particles originally in contact will be separated. In an ideal situation these pairs of particles are grouped about a plane normal to the direction of the tensile force and the tensile strength T can be defined as the force per unit area of this fracture plane required to break the compact. The tensile strength depends on the number of pairs of particles associated with the unit fracture plane Nppla which in turn depends on the sizes of the particles involved.Con- sidgr a volume marked out by tlLe centres of the pairs of particles. On average this volume is d per unit area of split (where d is the mean effective diameter which will be defined below) and the number of particles contained therein is where ArPBIV is the number of pairs of particles per unit volume of the compact which is related to the number of particles per unit volume of the compact ATPIv by - N,,, = dXDP,V . . * . .. * . * . (2) The latter in turn is related to the density of the compact by Therefore N*/vCp'ps = p . . * . .. .. . * (4) N D D / & = - - - .. .. .. . . ' ' (5) c Z p 2 Cpps 18 PARTICLE SIZE ANALYSIS [Proc. Soc. Analyt. Chem. The second factor determining the tensile strength is the force F which acts between the particles in a pair of particles.In general F will be inclined a t an angle 0 to T and it is the resolved component F cos 8 that co3tributes to T . Assuming that all 8 are equally probable the mean effective value of F F can be found by averaging over 6 - . . * . (6) F = + F . . .. * . Since the particles are not smooth when they come into contact it is the surface pro- An area of contact Aij can be defined within trusions that touch and form micro-contacts. which the micro-contacts lie and then F can be expressed in terms of this area where 12 is the interparticle force per unit area of contact. I t also depends on the property of h which arises because of the presence of van der IYaals electrochemical and other interatomic forces that depend on distance between the interacting atoms. In addition the number of micro-contacts at which the interatomic forces act also varies as the surface separation t between the two particles varies.Therefore h is a function of 1 The exact mathematical relation between h and t is unknown but in general it can be expected that h is large when t tends to zero and it falls to zero when t attains some charac- teristic value 1,. The distance I between particle centres in a pair of particles is . . . . ( 7 ) F = hAij . . . . . . The area of contact depends on the sizes of the two particles involved. . . . . (8) h = h(t) * . . . The surface separation can be related to the compact density. .. . . ’ . (9) I = +(di + dj) + t . . . . If it is assumed that there is no change in the type of particle packing as density changes- 1 P E p .. I . .. . . (10) Then for small changes to - t .... . Po which rearranges into In these equations po is the density at which t = to and d has been substituted for 1. The area of contact can now be defined as the area over which the separation between any two points one on the surface of one particle and the other on the second particle is less than to. For two spherical particles of diameters di and d j respectively . . (13) Summarising the factors that contribute to the tensile strengtli- T = C f .. . I . . . . . . . . (14) for all pairs of particles in unit area of split. From equations (6) and (7)- T = I ] dij .. . . .. . . . . (15) for all pairs of particles in unit area of split. On grouping the pairs of particles according to the particle sizes involved- xijSPP a -4ij . . . . . . . (16) January 1973 PARTICLE SIZE AKALTSIS 19 where xij is the proportion of pairs of particles out of all possible pairs that are composed of particles of sizes di and dj.On using equations (5) and (13)- . . .. . . . . (17) where .. .. * . .. . . (18) di + dj S = i ? i < j Equations (15) and (12) are the theoretical relations linking T to experimental quantities. I t is shown in the earlier paper1 how pa can be deduced from experimental results. The particle-size parameters d S and 5 can be calculated if the particle-size distribution is known. For example if the distribution consists of number fractions ni nj . . . . . . . . of spheres of diameters di dj . . . . . . . . . then i < j I . .. .. . . (20) i < j and ; = 2 nidi3 .. .. .. .. . . (21) 6 i and S is given by equation (18) and from the use of equation (19).fractions in the form The theory can be tested by plotting data obtained by using different particle-size T d~ pips against (i - 1) when the data for different size fractions fall on the same curve. From this curve the value of to can be deduced and hence the function k ( t ) can be constructed in the form of a master curve which can then be used to generate the tensile strength of any other compacts for which the particle-size distributions are known. By invoking the principle of corresponding states it is possible to arrive a t a useful method for comparing the interparticle forces1 and shear properties3 of different powders or granular materials. The effect of particle shape can be introduced by modifying equations (13) (18) and (20) and this aspect of the problem is currently being studied a t li’arren Spring Laboratory. 4 77 1 - PIPS Further extension of the theory to cover moist powders is possible.2 REFEREXES 1. -. 3 3. Chcng D. C.-H. Chew. Engng Sci. 1968 23 1403. __ J . Adhesion 1970 2 82. Chcng D. C.-H. Farley R. and Valetitin F. H. H. Insin Chew E n g ~ s Synzp. Sw. S o . 29 1968 14.

ISSN:0037-9697    

DOI:10.1039/SA9731000013

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

20 OBITCARY [Proc. SOC. Analyt. Cizenz. Obituary NORhIAN EVERS WHEX Dr. Xorman Evers died on October 25th 1972 a t the age of 85 the Society lost its member of longest standing and one who through his work for Apzalytical Abstracts must rank as having made a very significant contribution to the success the Society enjoys today Sorman Evers was born a t Faversham in Kent in 1887 and was educated at Faversham Grammar School and then King’s College London graduating in 1911 the year he joined our Society. After a brief spell in a Public Analysts’ Laboratory in Birmingham he joined Allen & Hanburys Limited in 1912 spending the whole of his first career (until 1952) with that firm for many years being their Director of Research. During this time he made important contributions to the development of the pharmaceutical industry ; he was Chairman of the British Pharmaceutical Conference in 1947 and 1948 and he served on a number of committees of the British Pharmacopoeia Commission the British Pharmaceutical Codex and the British Standards Institution.He was an examiner in pharmaceutical chemistry for both the Pharmaceutical Society and the Royal Institute of Chemistry. He wrote two books-“Chemistry of Drugs” and with G. D. Elsdon “The Analysis of Drugs and Chemicals,” which made a valuable contribution to the literature of the time. He took an early interest in the affairs of our Society being a member of Council in 1921-22 and 1929-30. I worked in his laboratory at Bethnal Green for 4 years from 1932 and it was an un- forgettable experience. His meticulous attention to detail made certain that there were no problems of communication about the job to be done-lie knew what he wanted and so did you.One soon realised that his somewhat austere manner only thinly disguised good humour and an enjoyment of life-why else would the bound volumes of Punch occupy a prominent place in a laboratory library? Where else too did the majority of the staff sit down to a cooked lunch a t a table in the middle of the laboratorj (not possible today) and then be commanded by the boss to play bridge or table tennis for the remainder of the lunch hour? His laboratories a t Bethnal Green were destroyed by enemy action in 1941 and he then moved his staff to IVare in Hertfordshire. It was fortunate for the Society that he retired from Allen 8 Hanburys Limited in 1952.Abstracts had been published in The A~zalyst from 1876 until the end of 1949 after which members received British Abstracts C. However the Bureau responsible for this publication was to terminate its activities a t the end of 1953 and the Society was planning to launch its own separate abstracts journal as a replacement and so continue the service provided for so long. Dr. Kent-Jones the President at that time and a life-long friend persuaded Dr. Evers as he had become in 1945 to be the first Editor of the new journal which was to be called Aizalytical Abstracts and Evers in turn successfully persuaded many of his colleagues to prepare abstracts for him. So in January 1954 the first monthly issue of the new journal appeared and the planning and meticulous attention to detail displayed by its Editor was such that the general arrangement and form of the abstracts are virtually unchanged today.Cnder his able leadership dna2yticalil bstracts grew rapidly and soon enjoyed a high reputation and a large and international circulation. Dr. Evers retired from the Editorship in 1962 having seen the annual publication of abstracts rise from 3190 to 5564 but for him it was only to mos7e from one chair in the office to another! He had always recognised the importance of indexes for an abstracts journal taking a special interest in the preparation of the annual Subject Indexes. Thus he next undertook the onerous task of compiling the Subject section of the cumulative Decennial Index of Analytical Absdracts covering some 46 200 abstracts for the years 1954 to 1963 and containing over 100 000 entries.He continued to be responsible for the annual and biannual Subject Indexes until the beginning of 1970 when he “retired” yet again and became one of our regular abstractors. He had also been responsible for the preparation of the material for the “Recent Books” feature since it started in 1967. He had served on the Abstracts Editorial Committee from its inception until the time of his death. His wide knowledge and experience made him one of its most valued members and during my periods as Chairman I have always been very acutely aware that no error of drug nomenclature by an abstractor or sub-editor ever stood any chance of going undetected by him. January 19731 PAPERS ACCEPTED FOR THE ANALYST 21 We in the Society will remember him with both affection and respect. He supported the Society and its scientific meetings as perhaps few others have done and it is fortunate indeed that he and his wife Phyllis were able to be the honoured guests of thelpresident at the Society’s dinner at Bath last Jlarch. In offering AIrs. Evers our heartfelt sympathy we assure her that her husband has a place in the Society’s history that few can emulate; lie will not readily be forgotten. A. G. JONES Chaivntapt Abstvacts Editovial Committee

ISSN:0037-9697    

DOI:10.1039/SA9731000020

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

January 1973; PAPERS ACCEPTED FOR THE ANALYST 21 Papers Accepted for Publication in The Analyst THE following papers have been accepted for publication in The Axalyst and are expected to appear in the near future. “Chemical Composition of Alleppy Cardamom Oil by Gas Chromatography,” by A. K. S. Baruah S. D. Bhagat and B. K. Saikia. “The Application of the Thin-layer Chromatographic Enzyme Inhibition Technique to Organochlorine Insecticides,” by M. Bogusz and T. Borkowski. “A Comparison of a Spectrophotometric (Quercetin) Method and an Atomic-absorption Method for the Determination of Tin in Food,” by Ase Engberg. “Ionic Polymerisation as a Means of End-point Indication in Non-aqueous Ther mo- metric Titrimetry. Part I The Determination of Organic Bases,” by E. J. Greenhow and L. E. Spencer.“Ionic Polymerisation as a Means of End-point Indication in Non-aqueous Thermo- metric Titrimetry. Part 11 The Determination of Organic Acids,” by E. J. Greenhow and L. E. Spencer. “Ionic Polymerisation as a Means of End-point Indication in Non-aqueous Thermo- metric Titration. Part 111 The Determination of Alkaloids and Alkaloidal Salts,’’ by E. J. Greenhow and L. E. Spencer. “The Determination of Oxygen and Carbon in Indium Phosphide by High-energy y-Photon Activation,” by J. S. Hislop and D. R. b‘illiams. “,iutomatic Logging and Processing of AutoAnalyzer Peaks with an Off-line Time- sharing Computer,” by J. D. Caisey and B. D. Riordan. “Non-aqueous Atomic-absorption Spectrophotometric Analysis of Organonickel Com- plexes by a Ligand Exchange Method,” by 11. A. Leonard and W. J. Swindall. “A Comparison of a Wet Pressure Digestion Xethod with Other Commonly Used \Vet and Dry Ashing Nethods,” by William J. Adrian. “A Gas-chromatographic Method for the Determination of Low Concentrations of Acrylic Acid in Mixtures of C to C Fatty Acids in Biological Materials,” by R. C. Noble and J. IY. Czerkawski. “Continuous Determination of Ammonia in Condensed Steam and High-purity Boiler Feed-water by Using a Potentiometric Ammonia Probe,” by D. llidgley and K. Torrance. “Determination of Sitro and Nitroso Compounds by Thermometric Titrimetry,” by L. S. Bark and P. Bate. “A Study of the Variation with pH of the Solubility and Stability of Some Metal Ions a t Low Concentrations in Aqueous Solution. Part 11,” by A. E. Smith.

ISSN:0037-9697    

DOI:10.1039/SA9731000021

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

22 XOTICES :Proc. SOC. ilnalyt. Chenz. Notices INTERNATIONAL SYMPOSIUM ON LIQUID SCINTILLATIOX COUNTING SEPTEMBER 3RD TO 6TH 1973 BRIGHTON THIS Symposium organised by the Radiochemical Methods Group of the SAC/Analytical Division will be held a t the Hotel Metropole Brighton. The principal themes will be Nodern Concepts of Liquid Scintillation Counting Sample Preparation and Quench Correction Techniques. Opportunity will be given for the presentation of short papers on these topics. Plenary lectures will be given by internationally known authorities including Dr. E. Mueller (nke Bush) Dr. B. E. Gordon Dr. V. Tarkkanen and Dr. R. Parker. The meeting will begin with a “teach-in” for those new to the technique of liquid scintillation counting. An extensive exhibition of liquid scintillation counters and related equipment has been arranged and the following firms will be exhibiting Beckman Berthold/Frieseke Inter- technique E.M.I.Ltd. LKB-Wallac Kuclear Chicago Yuclear Enterprises Packard Pye Unicam Tracerlab Fisons and Koch-Light. Papers which must be submitted to the Papers Committee should describe original unpublished work with particular reference to the main subject divisions. Intending contributors should send three copies of an abstract (about 500 words in English) by April lst 1973 to Mr. M. 4 . Crook Radiochemical Methods Group Society for Analytical Chemistry 9/10 Savile Row London W X 1AF. If you wish to be kept informed of arrangements and t o receive application forms when available please write to Miss P. E. Hutchinson Society for Analytical Chemistry 9/10 Savile Row London WlX 1AF.Lectures will be given by Dr. A. Dyer and Dr. E. Rapkin. DETECTORS FOR MEASUREMENT OF WATER POLLUTION JANUARY %RD 1973 LONDOX THE Electronics Division of The Institute of Electrical Engineers is organising this Colloquium which includes the applications of gas permeable and selective ion electrodes novel sensors recent developments in sensors and systems submersible monitors and on-line determination of ammonia with a membrane electrode. Further details can be obtained from the Secretary Institution of Electrical Engineers Savoy Place London WC2R OBL. SEVENTH INTERNATIOXAL CONFERENCE OS IS’ATER POLLUTION RESEARCH SEPTEMBER ~ T H TO 1 3 ~ ~ 1974 PARIS COMPLETED papers on all aspects of water pollution research in the freshwater and marine environment are invited before November 7th 1973 for the above Conference. Details concerning the subjects of interest and the form of submission of papers can be obtained from Dr. S. H. Jenkins Upper Tame Main Drainage Authority 156/170 Newhall Street Birmingham B3 1SE.

ISSN:0037-9697    

DOI:10.1039/SA9731000022

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

23 January 1973; SHORT COURSES Short Courses of Interest to Analytical Chemists Available at Universities Colleges of Technology and Polytechnics in the U.K.* SUBJECT DATES Full-time coursest- Recent Advances in March 13-13 1973 Analytical Instrumental Techniques Chemical and Bio- chemical Analysis Itelated Methods Radioisotope Methods in March 19-23 1973 Spectrofluorimetry and March 22-23 1973 Postgraduate School in April 2-6 1973 Integrated Spectroscopic Techniques Electroanalytical April 2-6 1973 Chemistry Quantitative Aspects of April 9-10 1973 Thermal rhalysis Recent Advances in April 12-13 1973 Research in Analytical Chemistry On-stream Analysis ;\lay 11 1973 Soiiic Recent May 18 1973 Developments in Spectroscopy Spectroscopy in Chemistry Biology and Medicine (Practical Course) htomic-absorption June 14-15 1973 Ion-selective Electrodes July 10-12 1973 Part-time courses- Introductory Statistics Feb.30 1973 lor Chemists ( 5 Tuesdays e ) (Emphasis on treatment of analytical data) Spectroscopy (5 Thursdays e ) Photoelectron March 8 1973 Separation and Identifi- cation of Polymers LJsing Chromatographic Techniques -1nalysis (6 Thursdays) April 3 1973 ( 5 Tuesdays e ) .Applications of Thermal hIay 3 1973 PLACE Thames P. C. Bath Loughborough U.T. U. Sussex U.JI.1 S.T. Hatfield P. U M I.S.T. Hatfield P. Hatfield P. U.X.I.S.T. U.M.I.S.T. Newcastle P. Thames P. Newcastle P. Kingston P. COXTACT for further infornzatiolz Dr R. C. Denney School of Chemistry Thames Polytechnic Wellington Street London S.E.18. Director Centre for Adult Studies University of Bath Northgate House Bath B-41 L4L.Dr. D. Thorburn Burns University of Technology Loughborough Leics. LEll 3TU. Dr. M. D. Robinson Education Officer The Chemical Society Burlington House London W l V OBN. Secretary and Registrar U.M.I.S.T. P.O. Box 88 Manchester AT60 1QD. Dr. D. V. Xowell Dept. of Chemical Sciences Hatfield Polytechnic College Lane Hatfield Herts. See above. Dr. 111. R. Evans Dept. of Chemical Sciences Hatfield Polytechnic College Lane Hatfield Herts. Dr. 31. B. Evans. See above. See above. See above. \V R. Tomlinson Chemistry Dept. Newcastle upon Tyne Polytechnic Ellison Place Xewcastle upon Tyne NEI 8ST. Dr R. Thomas School of Chemistry Thames Polytechnic Wellington Street London S.E.18. See above. Head of Dept. of Chemical Science and Technology Kingston Poly- technic Penrhyn Road Kingston upon Thames Surrey KT1 2EE. * This list does not contain courses already announced in earlier lists. The previous list appeared in the November 1972 issue of Proceedings p 235. These are all-day courses lasting one or more days. t .4bbreviations C.T = College of Technology; P = Polytechnic; U. = University U.T. = Uni- _. x-ersity of Technology. a = afternoon; e = evening. $ These courses comprise weekly lectures extending over a period of several weeks. Abbreviations :

ISSN:0037-9697    

DOI:10.1039/SA9731000023

出版商:RSC    

年代:1973

数据来源: RSC