April, 19711 THE ANALYST xiiiFOR SALE~ ~~~Spectrographic System consisting of 3.4 metre Hilger Jaco EbertGrating Spectrograph Source Unit FS131, Arc and Spark Stand FS55,Comparator Microphbtometer L99, and a selection of accessories.Inspection and iurther information can be arranged by contactingThe Laboratory Secretary, C.E.G.B., Berkeley Nuclear Laboratories,Berkeley, Glos.LECTURES AND COURSESUNIVERSITY OF BRISTOLDEPARTMENT OF INORGANICCHEMISTRYM.SC. COURSE IN ANALYTICAL CHEMISTRY(WITH SPECIAL REFERENCE TOINSTRUMENTAL METHODS)OCTOBER 1971-1972Applications are invited from persons whohold or expect to be awarded, an appropriatehonours degree or equivalent qualification.The course offers a complete background tothe principals and practice of InstrumentalAnalytical Chemistry.The aim is to develop a research approach toAnalytical Chemistry and investigations ofRelevant Analytical Problems includingPollution Studies will form a major part of thecourse.Applications and enquiries should be sent tothe Registrar, The University, Senate House,Bristol, 2, as soon as possible.UNIVERSITY OFLONDONM.Sc. Course inAnalytical ChemistryApplications are invited from persons whohold or expect to hold an appropriatehonours degree or equivalent qualifications,e.g. G.R.I.C.The Science ResearchCouncil has given a ‘Priority’ rating to thecourse for tenure of its Advanced CourseStudentships. These will be allocatedjointly by the two Colleges.The course is given at Chelsea College andImperial College.Following a core ofcommon lectures, separate options aregiven at each College.registered at one of the two collegesaccording to the expression of their interestsand the availability of space.and enquiries should be addressed to theRegistrar at either College.There is specialisation in organic analysis atChelsea College and in trace analysis atImperial College.Students will beApplicationsChelsea College, Imperial College,Manresa Road, South Kensington,London S.W.3. London S.W.7.BINDINGHave your back numbersof The Analyst bound inthe standard binding case.Send the parts and theappropriate index(es) to-gether with a remittancefor f I *90to:W. Heffer & Sons Ltd.Cambridge EnglandIf you have a problem i n standardising ananalytical procedure, the use of a solidreagent i n tablet form may be your answer.We have been manufacturing“ANALOID”COMPRESSED REAGENTSfor over 50 years.Our experience i s at your service and weshall be pleased to consider making tabletsfor your specific requirements if thesecannot be met from our standard range.Send your enquiries to:-RIDSDALE & CO.LTD.Newham Hall, Newby,Middlesbrough, Teesside TS8 9EATelephone: 0642 372 I SUMMAKIES OF PAPERS IN THIS ISSUEPotentiometric Method for the Determination of AromaticMonothiosemicarbazonesA method has been developed for the quantitative determination ofaromatic monothiosemicarbazones, in which addition of silver nitrate to asolution of the organic compound leads to complex formation.The hydrogenion liberated on complex formation is determined by potentiometric titration.M. J. M. CAMPBELL, R. GRZESKOWIAK and I. D. M. TURNERDepartment of Chemistry, Thames Polytechnic, London, S.E. 18.[April, 1971Analyst, 1971, 96, 286-287.The Determination of Glycerol by the I.U.P.A.C. Form of theMalaprade MethodThe accepted periodate m-thod for the determination of glycerol hascome under review by the International Organisation for Standardisation(Sub-committee ISO/TC47/GT2) and certain modifications have been sug-gested with regard to the different pH end-points for the sample and blankand the possible loss of formic acid from the system by volatilisation. Thepresent paper summarises the view of the U.K.delegates to ISO/TC47/GT2,which are :(i) The choice of pH about 8.0 for the sample is justified on the groundthat it contains formic acid in addition to strong acids. The blank, whichcontains only strong acids, should, on general grounds and by calculation,be titrated to pH 7.0. The use of pH 6-5 instead of 7.0 for the blank is anempirical correction designed to compensate for some lack of stoicheiometryor other bias in the procedure and to bring the results into agreement withthose obtained by independent moisture and specific gravity determinations.This “correction” amounts to 0.03 per cent.(ii) There is a potential loss of formic acid by volatilisation from thesystem (estimated variously to be equivalent to 0.01 to 0.04 per cent.ofglycerol), which partly explains the apparent lack of stoicheiometry.(iii) Modifications have been proposed to minimise this loss of formicacid and (by adding formate ions to both solutions) to unify the end-pointsat or about pH 8.0. Unless these modifications lead to a pronounced improve-nieiit in reliability, it seems doubtful whether further extensive trials on aninternational basis would be justified.R. F. BARBOURSewcastle Technical Centre, Procter & Gamble Ltd., Newcastle upon Tyne.and J. DEVINEUnilever Research Laboratory, IJnilever Ltd., Port Sunlight, Cheshire.Analyst, 1971, 96, 288-295.The Separation and Determination of Pentachlorophenol inTreated Softwoods and Preservative SolutionsA method is described for the extraction, separation and determination ofpentachlorophenol or its sodium salt in softwoods and preservative solutions.Pentachlorophenol is separated from lower chlorophenols and wood extrac-tives by adsorption on to Bio-Rad AG 2-x8 anion-exchange resin, eluted withglacial acetic acid, extracted into chloroform, and determined by spectro-photometric measurement of the blue 4-aminophenazone - pentachlorophenolcomplex.The effect of time and temperature on the oxidation - condensationreaction of 4-aminophenazone with pentachlorophenol has been investigated.The procedure is particularly useful for the study of the distribution ofpentachlorophenol-containing preservatives in wood.A.I. WILLIAMSDepartment of the Environment, Forest Products Research Laboratory, PrincesRisborough, Bucks.AndJ’st, 1971, 96, 296-305xviii SUMMARIES OF PAPERS I N THIS ISSUE [April, 1971The Determination of Ethanol in Paints, Inks and Adhesives byGas ChromatographyA gas-chromatographic method for the determination of ethanol inpaints, inks, adhesives and similar composite products has been developedby which the time required for the analysis of samples has been greatlyreduced.The ethanol is distilled azeotropically from the sample in thepresence of toluene, and the distillate is examined directly by gas chromato-graphy without any further treatment other than mixing with an internalstandard. The problem of the longer retention time of toluene, comparedwith those of the lower aliphatic alcohols, has been overcome by the use ofback-flushing. From the results obtained by the analysis in duplicate ofa series of samples, including a number prepared in the laboratory containingknown amounts of ethanol, the accuracy and precision of the method havebeen established.J. R.HARRISDepartment of Trade and Industry, Laboratory of the Government Chemist, Corn-wall House, Stamford Street, London, S.E.l.Analyst, 1971, 96, 306-309.The Determination of Residues of Dichlorvos and Malathionin Wheat Grain by Gas - Liquid ChromatographyA procedure is described for the determination of malathion and di-chlorvos in grain. After extraction with methanol, and clean-up on a charcoalcolumn, if required, the pesticide residues are determined by gas - liquidchromatography on Apiezon L and butane-1,4-diol succinate columns witha phosphorus-sensitive detector.Between the concentrations of 0-25 and 10 p.p.m.both pesticides wererecovered from spiked samples with between 87 and 99 per cent. efficiency.S. CRISP and K. R. TARRANTDepartment of Trade and Industry, Laboratory of the Government Chemist, Corn-wall House, Stamford Street, London, S.E.l.Analyst, 1971, 96, 310-313.The Microbiological Assay of the Vitamin B, Complex(Pyridoxine, Pyridoxal and Pyridoxamine) with Kloeckera BrevisA complete re-investigation of the microbiological assay of the vitaminB, complex (pyridoxine, pyridoxal and pyridoxamine) with the yeast Kloec-ksra brevis has been made. The superiority of the proposed method over otherse.g., those involving Saccharowzyces carlsbergensis 4228 (ATCC 9028), theprotozoan, Tetrahywzena pyri forwzis and the X-ray mutant Neurosfiorasitophila 299, is discussed and suitable methods of extraction are described,particularly for blood, liver, human and rat brain, and urine.Kloeckera brevis has also been found to be a more suitable organismfor the cup-plate assay of the vitamin B, complex than S.carlsbergensis.The zones of exhibition are sharp and clear and background growth is reducedto a minimum, which is frequently not so with S. carlsbergensis.E. C. BARTON-WRIGHTGalloway and Barton-Wright, Haldane Place, London, S.W. 18.Analyst, 1971, 96, 314-318.Potential Hazards by Formation of Silver Acetylide upon AspiratingSolutions Containing High Concentrations of Silver to anAtomic- absorption Spectrophotometer when Acetylene is Used as FuelCommunicationR.J. REYNOLDS and D. S. LAGDENEvans Electroselenium Research Laboratories, Braintree, Essex.Analyst, 1971, 96, 319xx THE ANALYST [April, 1971Microfiche Editions of The Andyst and Andytical AbstructsAs announced on page 88 of the current (April) issue of Proceedings of the Society for Analyticalchemistry, the Society proposes to produce a microfiche edition of The Analyst, and possibly ofAnalytical Abstracts also.The Analyst for 1969 (volume 94) will be published on microfiche shortly, price f 15; $36(reference: a).A reduced price (f7.50; $18) will be charged t o customers who subscribed during 1969 t othe (spaper” edition of The- Analyst.The future programme of microfiche production depends on the response to this initial offer.Customers, o r potential customers, are therefore urged t o write t o the publishers stating if theyare interested in ordering-(6) The Analyst for 1970 (volume 95) on microfiche;(c) Analytical Abstracts for I969 (volumes I6 and 17) ;(d) Analytical Abstracts for I970 (volumes I 8 and 19) ;(e) Current numbers, as published during 1971, of both journals.The prices of items (6) (c) and (d) are expected t o be similar t o that fixed for item ( a ) ; theprice of a current subscription (item a) i s expected t o be €25 ($60) t o subscribers not taking thestpaper” edition; o r f 12-50 ($30) to subscribers taking the “paper” edition.......................................................................................................................................................................................ORDER FORMTo the Society for Analytical ChemistryBook Department9/10 Savile Row, London WIX IAF(a) Please supply I set of microfiche containing The Analyst for 1969, volume 94, at the full priceof € I5/$36* a t the special reduced price of f7.50/$18*Tot .........................................................................................................................................................................................* Delete parts that do not apply.i If the special reduced price is t o be paid, this address should be identical with that t o which the “paper”subscription was sent in 1969; if the customer has moved in the meantime, the former address should also be giveni n a note sent with this order.Please tickappropriate box(es) I will pay on receipt of invoice(b) I am interested in obtaining later volumes of The Analyst... . . . . . . . . . . .(c, d) I am interested in obtaining Analytical Abstracts on microfiche. . . . . . . . . . . 0(e) I am interested in a current subscription (from January 1971) t o both Analyst and( f ) I am considering purchasing a microfiche edition; please send a specimen fiche. . . . .Analytical Abstracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . April, 19711 THE ANALYSTAn ‘impossible’ analytical problem?xxitwo minutes from nowyou could be on the way to solving itActivation analysis is a fast-developing technique particularlyhelpful in solving difficult problems of trace element analysis.It offers a unique combination of extreme sensitivity with unam-biguous identification of an impurity. Sample contamination andreagent ‘blank’ errors are avoided and the technique can often beused non-destructively. An Activation Analysis Unit has now beenestablished at Harwell in collaboration with the Analytical Re-search & Development Unit. If you would like further details, orwould like the opportunity to discuss ways in which we can helpto solve your particular problems, complete and post the couponor ring Abingdon 4141, Ext.3085.To :Activation Analysis Unit, Harwell, Didcot, Berks.I am interested in the services of the Activation Analysis Unit.I should like to :Receive further information by post c] Discuss my problem with youI am also interested in assistance with :c] IR spectrometry 0 mass spectrometry 17 NMR spectrometryc] computer applications c] on-line analysisother analytical techniques (tick as a~~romiate)Name ,AddressAA 1