ANALAO 104 (1 236) 177-272 (1 979)ISSN 0003-2654March 1979 'THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICAL SOCIETYCONTENTS177196201208224232241248258261265269Energy-dispersive X-ray Emission Analysis.Analysis of Steroids. Part XXXII. Determination of Allyloestrenol by Titri-metric, Polarographic and Gas-chromatographic Methods-Sandor Gorog,Anna Lauko and Zsofia SziklayA Review-W. C. CampbellDiffusion Assay by an Automated Procedure-J. W. Lightbown, R. A. Broadbridge,P. Isaacson, J. E. Sharpe and A. JonesMechanism of Atom Excitation i n Carbon Furnace Atomic-emission Spectro-metry-D. Littlejohn and J. M. OttawayDetermination of Chromium in Natural Waters and Sewage Effluents byAtomic-absorption Spectrophotometry Using an Air - Acetylene Flame-K.C. Thompson and K. WagstaffDetermination o f Selenium i n Soil Digests by Non-dispersive Atomic-fluorescence Spectrometry Using an Argon - Hydrogen Flame and theHydride Generation Technique-J. Azad, G. F. Kirkbright and R. D. SnookInvestigations on Reaction Mechanisms in the Determination o f Non-ionicSurfactants in Waters as Potassium Picrate Active Substances-L. Favretto,B. Stancher and F. TunisLimit of Detection in Analysis w i t h lon-selective Electrodes-Derek MidgleySHORT PAPERSSpectrophotometric Method for the Determination of Paraquat-M. Ganesan,S. Natesan and V. RanganathanTitrimetric Determination of Reducing Sugars with Copper( II) Sulphate-T. H. KhanDetermination o f Dimetridazole i n Pig and Poultry Feeds by High-performanceLiquid Chromatography-A.D. Jones, I. W. Burns and S. G. SellingsBook ReviewsSummaries of Papers in this Issue-Pages iv, v, viii, xPrinted by Heffers Printers Ltd Cambridge EnglandEntered as Second Class at New York, USA, Post OfficEuro-Standardsavailable fromBUREAU OF ANALYSEDSAMPLES LTD.Newham Hall, Newby,Middlesbrough, Cleveland TS8 9EA(Telephone: Middlesbrough 31 721 6)A range of over 30 samples in finely dividedform:Unalloyed SteelsAlloy SteelsCast IronsFerro-AlloysIron OresDustsThese samples have been analysed by 20laboratories from countries within the EEC.Full details on request.APPOINTMENT VACANTLancashire County CouncilCounty Laboratory - Assistant Analyst(Salary ~€4,461- &4,761 per annum + &312 perannum supplement)Applicants should have BSc.Honours (Chemistry) orM.R.I.C. Experience of Food Chemistry preferable.Application forms from Chief Executive/Clerk (Ref:41/PAT), County Hall, Preston, PR1 SXJ (Preston54868, Ext. 566) t o be returned by 22nd March 1979.BRITISH PATENT NO. 1 407 298Filtering ElementOwner desires commercial exploitation on reasonable terms by licenseor sale. Inquiries Fitzpatricks Chartered Patent Agents 14-1 8 CadoganStieet, Glasgow, G2 6QW ’and Warwick House, Warwick Court,London, WClR 5DJ.FOR SALEThe Analyst 1952-70; Journal of the Association ofPublic Analysts 1965-71 and Reports on the Progressof Applied Chemistry 1963-99.Telephone 01-204 6871 (evenings).THE QUEEN’S UNIVERSITYOF BELFASTMSc COURSE inANALYTICAL CHEMISTRYApplications are invited for admission to thisestablished 12 month full-time MSc coursewhich provides a comprehensive training inthe theory and practice of modern chemicaland instrumental methods of analysis. Appli-cants should normally possess an honoursdegree (or equivalent) in chemistry or cognatesubjects. Part-time courses are available.The Science Research Council has recognisedthe course for tenure of its Advanced CourseStudentships.A description booklet and application formscan be obtained from Professor D. ThorburnBurns, Dept. of Chemistry, Queen’s Universityof Belfast, Belfast, BT7 1 NN, Northern Ireland