December, 19731 THE ANALYST ixFOR SALE~~THE ANALYST 1890 to 1956continuous, with a few copies 1885 to 1889. Two copiesmissing Dec. 1946 and Jan. 1952. V,'ell bound annuallyexcept 1946 and 1952-1956.Offers invited (including delivery).Box no. 234c/o J. Arthur Cook9 Lloyd SquareLondon WClX 9BASpecimen copies supplied in advance if desired.APPOINTMENTS VACANTPARTICLE SIZEANALYSIS1970THE Society for Analytical Chemistryhas published in this book all paperspresented at the Second Particle SizeAnalysis Conference, held in Bradfordin September 1970, and the full discus-sions on them.The 35 papers cover all aspects ofresearch into the subject, basicallycovering the 4-year period since the firstconference was held in Loughboroughin 1966, and include plenary lectures bythe late Professor H.Heywood and byProfessor K. Leschonski. The volumeis a companion to "Particle SizeAnalysis" - the report of the First Con-ference, also published by the Society.Pp. x + 430Price S7.750 btai nable from-THE SOCIETY FORAN ALYTI c A L CHEMISTRY,(Book Department),9/10 Savile Row, London, W1X 1AFMembers of The Chemical Society may buypersonal copies at the special price of S6.2X THE ANALYST [December, 1973APPOINTMENTS VACANTDEVELOPMENTCHEMISTWe manufacture feeds for farm livestock in our nine factories inEngland and Ulster. Our Research and Advisory Department inlpswich carries out development work and provides a technicalservice to our branches, there is close liaison with UniversityAg ricu I t u ra I Depart men ts and other organ isa ti ons.Following a recent promotion, we are looking for a man to work in ourlaboratories on problems on animal nutrition.He will work closelywith graduate staff specialising in this field and may be involved intrials at our experimental farm.You will need sound practical analytical experience and the ability towork with minimum supervision on a wide variety of projects. Wewould prefer you to be qualified to R.I.C. standard, but will consider alesser qualification backed by experience in food or feed analysis, or ina consultant laboratory.Conditions of service are excellent and include annual bonus, pensionand insurance schemes. Initial salary will be based on qualificationsand experience.Please write for an application form to C.S. Drake, Group PersonnelOfficer, Pauls and Whites Limited, P.O. Box 39, lpswich 1 P4 1 BX.Telephone (0473) 5671 1.BINDINGHave your back numbers of The Analyst bound in the standard binding case.Send the parts and the appropriate index(es) together with a remittance for€2.65 to:I. S. WILSON & SON14a Union Road, Cambridge CB2 I H December, 19731 THE ANALYST xiAPPOINTMENTS VACANTAnalytical ChemistThe Union International Co. Ltd. has a vacancy at the St. Albans ResearchCentre for an Analytical Chemist.The work will involve the development of new methods and the analysisof a wide range of materials associated with the food and pharmaceuticali nd u st r i es.Applications are invited from recently qualified Chemists and also fromthose who have had several years analytical experience.A good salary will be offered to the successful applicant and there are theusual fringe benefits.Please write giving age and full details of qualifications and experience tothe Staff Manager (AD 5763), 14 West Smithfield, London, E.C.1.ANALYTICAL SCIENCES MONOGRAPHNo.IH ig h- Precision Titri met ryby C. Woodward and H. N. RedmanImperial Chemical Industries Limited (Agricultural Division)BRIEF CONTENTS:lntro ductionVisual Titrations, with sections on Apparatus, Standard Substances and their preparation andassay, and Standard Solutions.Instrumental Methods, with sections on Photometric Titrations, Electrometric Titrations andMiscellaneous Techniques.References to the literature of high-precision titrimetry.Price f2.50Pp.viii+63 ISBN 0 85990 50: 2Society for Analytical Chemistry, Book Department,911 0 Savile Row, London, W1 X 1 AFMembers may buy personal copies at the special price of f2.0xii SUMMARIES OF PAPERS I N THIS ISSUEVoltammetric Determination of Tocopherols by Use of a NewlyDeveloped Carbon Paste ElectrodeA voltammetric method is described for determining tocopherols invegetable oils, foods and pharmaceuticals by a newly developed carbon pasteelectrode. The samples are saponified and the unsaponifiable fraction isextracted and determined voltammetrically. No elaborate purification methodis necessary as the substances that interfere with photometric proceduresare electrochemically inactive in the potential range of operation.Detailedprocedures for the preparation and the working of the electrode, and resultsfor the precision of the method, are presented.SAMUEL S. ATUMA -and JORGEN LINDQUISTDepartment of Analytical Chemistry, University of Uppsala, Box 531, S-751 21,Uppsala 1, Sweden.Analyst, 1973, 98, 886-894.[December, 1973Polarographic Studies of the Zinc(I1) Complex Formed withTyrosine in Aqueous and Mixed Aqueous and Non-aqueous MediaThe reduction of zinc(I1) in tyrosine solutions has been studied a t adropping-mercury electrode in aqueous and mixed aqueous and non-aqueousmedia. The effects due to variation of pH, temperature, ligand concentrationand height of the mercury column on the wave characteristics have beeninvestigated and the results interpreted.Under all experimental conditionsthe reduction has been found to be irreversible and diffusion controlled.Hence, the kinetic parameters, transfer coefficient (M,,) and formal rateconstant (Kof,h) have been calculated by use of Koutecky's method as im-proved by Meites and Israel. The analytical implication of the sytem hasalso been suggested.DAYA NAND CHATURVEDI and C. M. GUPTAChemical Laboratories, University of Rajasthan, Jaipur-4, India.Analyst, 1973, 98, 895-899.Determination of Organoisothiocyanates Alone and in Mixtureswith Organoisocyanates or ThioureasAn iodatometric method for the determination of organoisothiocyanatesis described.The isothiocyanates are quantitatively converted with n-butyl-amine in dimethylformamide medium into the corresponding symmetricalNN-disubstituted thioureas, which are titrated visually or potentiometricallyin acidic medium with potassium iodate solution. Methods have also beendeveloped for the analysis of isothiocyanate - isocyanate and isothio-cyanate - thiourea mixtures on the same sample solution. A known excessof the standard n-butylamine solution added to the mixture in dimethyl-formamide converts the isothiocyanate and isocyanate into the correspondingdisubstituted thiourea and urea, respectively. Acidimetric titration of theexcess of amine, and iodatometric titration of the thiourea present andformed, enable the particular mixture to be analysed for both constituents.The end-points can be detected both visually and potentiometrically.Themethods described are simple, accurate, reliable and widely applicable.BALBIR CHAND VERMA and SWATANTAR KUMARDepartment of Chemistry, Punjabi University, Patiala, India.Analyst, 1973, 98, 900-905December, 19731 SUMMARIES OF PAPERS I N THIS ISSUE xiiiDetermination of Bacitracin in Animal Feeds that Contain CopperA modification of the method involving the use of acidified methanolfor the analysis of animal feeds that contain bacitracin and copper sulphateas additives has been developed. Because of the interference of copper inthe bacitracin assay, the copper is precipitated by the addition of 3 to 4 molof sulphide ions per mole of copper.The method has been used for feedsamples that contain 5 to 20 p.p.m. of bacitracin and 100 to 300 p.p.m.of copper.B. GRYNNE, E. HOFF, T. SILSAND and K. VAAJEA/S Apothekernes Laboratorium for Specialpraeparater, Oslo, Norway.Analyst, 1973, 98, 906-907.The Determination of Nifursol in Animal FeedsReport prepared by the Prophylactics in Animal Feeds Sub-committee.ANALYTICAL METHODS COMMITTEE9/10 Savile Row, London W1X 1AF.Analyst, 1973, 98, 908-911.ANNUAL REPORTS ON ANALYTICALATOMIC SPECTROSCOPYVolume 2, 1972This comprehensive and critical report of developments in analytical atomicspectroscopy has been compiled from more than 1000 reports receivedfrom world-wide correspondents who are internationally recognised authori-ties in the field and who constitute the Editorial Board.In addition tosurveying developments throughout the world published in national orinternational journals, a particular aim has been to include less widelyaccessible reports from local, national and international symposia andconferences concerned with atomic spectroscopy.Volume 2 covers the year 1972216 pages Price f5.00 ISBN 0 85990 252 8Obtainable from The Society for Analytical Chemistry,(Book Department), 9/10 Savile Row, London, WIX IAFMembers of The Chemical Society may buy personal copies at the special price of €3.0xiv THE ANALYST [December, 1973Reprints of Review PapersREPRINTS of the following Review Papers published in The Analyst since January, 1963, areavailable from The Society for Analytical Chemistry, Book Department, 9/10 Savile Row, London,W1X 1AF (not through Trade Agents).Orders MUST be accompanied by a remittance for thecorrect amount made out to “Society for Analytical Chemistry.”“Classification of Methods for Determining Particle Size,” by the Particle Size Analysis“Methods of Separation of Long-chain Unsaturated Fatty Acids,” by A. T. James (August,“Beer’s Law and its Use in Analysis,” by G. F. Lothian (September, 1963).“A Review of the Methods Available for the Detection and Determination of Small Amounts“Circular Dichroism,” by R. D. Gillard (November, 1963).“Information Retrieval in the Analytical Laboratory,” by D. R. Curry (November, 1963).“Thermogravimetric Analysis,” by A. W. Coats and J. P. Redfern (December, 1963).Price“Some Analytical Problems Involved in Determining the Structure of Proteins and Peptides,”“The Faraday Effect, Magnetic Rotatory Dispersion and Magnetic Circular Dichroism,” by“Electrophoresis in Stabilizing Media,” by D. Gross (July, 1965).“Recent Developments in the Measurement of Nucleic Acids in Biological Materials,” by“Radioisotope X-ray Spectrometry,” by J , R. Rhodes (November, 1966).“The Determination of Iron(I1) Oxide in Silicate and Refractory Materials,” by H. N. S.“Activation Analysis,” by R. F. Coleman and T. R. Pierce (January, 1967).“Techniques in Gas Chromatography. Choice of Solid Supports,” by F. J . Palframan“Heterocyclic Azo Dyestuffs in Analytical Chemistry,” by R. G. Anderson and G. Nickless“Determination of Residues of Organophosphorus Pesticides in Food,” by D.C. Abbott and“Radioactive Tracer Methods in Inorganic Trace Analysis : Recent Advances,” by J . W.“Gamma-activation Analysis,” by C. A. Baker (October, 1967).“Precipitation from Homogeneous Solution,” by P. F. S. Cartwright, E. J. Xewman andD. W. Wilson (November, 1967).“Industrial Gas Analysis,” by (the late) H. N. Wilson and G. M. S. Duff (December, 1967).Price 35p.“The Application of Atomic-absorption Spectrophotometry to the Analysis of Iron andSteel,” by P. H. Scholes (April, 1968).“Inorganic Ion Exchange in Organic and Aqueous - Organic Solvents,” by G. J . Moody andJ . D. R. Thomas (September, 1968).“Radiometric Methods for the Determination of Fluorine,” by J . K. Foreman (June, 1969).Price 25p.“Techniques in Gas Chromatography.Developments in the van Deemter KateTheory of Column Performance,” by E. A. Walker and J. F. Palframan (August, 1969).Price 25p.Choice of Detectors,” by T. A. Gough andE. A. Walker (January, 1970)’.Sub-committee of the Analytical Methods Committee (March, 1963).1963). Price 25p.Price 25p.Price 25p.of Cyanide,” by L. S. Bark and H. G. Higson (October, 1963). Price 25p.Price 15p.Price 15p.25p.by Derek G. Smyth and D. F. Elliott (February, 1964).J . G. Dawber (December, 1964).Price 25p.Price 25p.Price 25p.H. N. Munro and A. Fleck (February, 1966). Price 25p.Price 25p.Schafer (December, 1966). Price 25p.Price 25p.Part I.and E. A. Walker (February, 1967).(April, 1967). Price 25p.H. Egan (August, 1967).McMillan (September, 1967). Price 25p.Price 25p.Price 25p.Price 25p.Price 25p.Price 25p.Price 35p.Part 11.“Techniques in Gas Chromatography.Price 25p.“Laser Raman Spectroscopy,” by P. J . Hendra and C. J . V e n (April, 1970).“Ion-selective Membrane Electrodes,” by Ern0 Pungor and KlAra T6th (July, 1970). Price“X-ray Fluorescence Analysis,” by K. G. Carr-Brion and K. W. Payne (December, 1970).“Mass Spectrometry for the Analysis of Organic Compounds,” by A. E. Williams and H. E.“The Application of Non-flame Atom Cells in Atomic-absorption and Atomic-fluorescence“Liquid Scintillation Counting as an Analytical Tool,” by J. A. B. Gibson and A. E. LallyPart 111.Price 35p.35p.Price 25p.Stagg (January, 1971). Price 35p.Spectroscopy,” by G. F. Kirkbright (September, 1971).(October, 1971). Price 25p.Price 25p