iv SUMMARIES OF PAPERS IN THIS ISSUE [July, 1973of Papers in this IssueMass and Charge Transfer Kinetics and CoulometricCurrent Efficienciesand Lewartowicz Methods, and Apparatus and Procedures forRamping VoltammetryA comparison is made of the provenance and application of patterntheory, Tafel, Allen and Hickling and Lewartowicz methods for the deter-mination of charge-transfer kinetic parameters. A general-purpose electro-chemical cell is described together with a ramping potentiostat - galvanostatfor slow single-sweep voltammetry. The mass-transfer characteristics, whichare governed by the geometrical placing of the various appurtenances thatdip into the solution and by the stirring speed, were examined by determiningthe apparent diffusion layer thickness at various stirring speeds for asystem of known mass-transfer properties, copper(I1) - copper(1).It wasfurther established that the limiting current of reduction of hexacyano-ferrate(II1) is reproducible and linearly related to concentration.E. BISHOP and P. H. HITCHCOCKChemistry Department, University of Exeter, Stocker Road, Exeter, EX4 4QD.Analyst, 1973, 98, 465-474.Part V. Comparison of Pattern Theory, Tafel, Allen and HicklingMass and Charge Transfer Kinetics and CoulometricCurrent Efficienciesthe Effects of Oxidation of PlatinumPart VI. The Pre-treatment of Solid Electrodes, and a Review ofThe nature and condition of working electrode surfaces are set in thecontext of reaction speeds and current efficiencies. The formation of filmsand their effects are examined for platinum and other metals and alloys.Adsorption and specific adsorption on electrode surfaces are briefly reviewed.An attempt is then made critically to appraise the current state of the artin respect of the activation and deactivation of electrodes.Methods ofcleaning electrodes are canvassed. The more significant theories of activationand deactivation are reviewed with specific reference to platinum electrodes.These theories include the impurity theory, the platinisation theory andthe various oxygen-containing surface theories. For the last, the formationof oxides, the measurement of film thickness, the film thickness and thenature of the oxide reducible a t 0-6 V are discussed, followed by a selectivereview of the oxygen-bridge theory, the half-reduced oxide theory and theplatinum - oxygen alloy theory.Tentative conclusions are reached. Finally,gold electrodes and their behaviour are briefly examined.E. BISHOP and P. H. HITCHCOCKChemistry Department, University of Exeter, Stocker Road, Exeter, EX4 4QD.Analyst, 1973, 98, 475-484July, 19731 THE ANALYSTTHE ANALYSTVEDITORIAL ADVISORY BOARDChairman: H. J. Cluley (Wembley)*L. S. Bark (Salford) W. Kemula (Poland)*G. F. Kirkbright (London)G. W. C. Milner (Harwell)G. H. Morrison (U.S.A.)*J. M. Ottaway (Glasgow)*G. E. Penketh (Billingham)S. A. Price (Tadworth)D. 1. Rees (London)E. B. Sandell (U.S.A.)*R. Sawyer (London)A. A. Smales, O.B.E. (Harwell)H. E. Stagg (Manchester)E.Stahl (Germany)A. Walsh (Australia)T. S. West (London)P. Zuman (U.S.A.)R. Belcher (Birmingham)L. J. Bellamy, C.B.E. (Waltham Abbey)L. S. Birks (U.S.A.)E. Bishop (Exeter)E. A. M. F. Dahmen (The Netherlandsj*J. B. Dawson (Leeds)A. C. Docherty (Billingham)D. Dyrssen (Sweden)*W. T. Elwell (Birmingham)*D. C. Garratt (London)*R. Goulden (Sittingbourne)J. Hoste (Belgium)D. N. Hume (U.S.A.)H. M. N. H. Irving (Leeds)A. G. Jones (Welwyn Garden City)M . T. Kelley (U.S.A.)*A. Townshend (Birmingham)*J. A. Hunter (Edinburgh)* Members of the Board serving on the Executive Committee.NOTICE TO SUBSCRIBERSSubscriptions for The Analyst, Analytical Abstracts and Proceedings should beThe Chemical Society, Publications Sales Office,Blackhorse Road, Letchworth, Herts.Rates for 1973(other than Members of the Society)sent to:(a) The Analyst, Analytical Abstracts, and Proceedings, with indexes . .. . €37.00(b) The Analyst, Analytical Abstracts printed on one side of the paper (withoutindex), and Proceedings . . . . . . . . . . . . . . €38.00(c) The Analyst, Analytical Abstracts printed on one side of the paper (withindex), and Proceedings . . .. . . . . . . . . . . L45.00The Analyst and Analytical Abstracts without Proceedings-(d) The Analyst and Analytical Abstracts, with indexes . . . . . . . . €34.00(e) The Analyst, and Analytical Abstracts printed on one side of the paper (withoutindex) . . . . . . . . . . . . . . . . . . €35.00(f) The Analyst, and Analytical Abstracts printed on one side of the paper (withindex) .. . . . . . . . . . . . . . . . . €42.00(Subscriptions are NOT accepted for The Analyst and/or for Proceedings alone)v1 SUMMARIES OF PAPERS I N THIS ISSUE [July, 1973Ionic Polymerisation as a Means of End-point Indication inNon-aqueous Thermometric TitrimetryPart IV. The Determination of Catecholamines(-)-Adrenaline, adrenaline hydrogen tartrate, L-noradrenaline, dopaminehydrochloride, L-dopa, DL-dopa, L-ct-methyldopa, D-a-methyldopa and ( + ) -Corbasil have been determined in amounts down to 0.0001 mequiv by catalyticthermometric titration of their basic and acidic functions. Basic functionswere determined by titration with 0.1, 0.01 and 0.001 M perchloric acid byusing the ionic polymerisation of a-methylstyrene to indicate the end-point,while acidic functions were determined in a similar manner with tetra-n-butyl-ammonium hydroxide as the titrant and acrylonitrile as the end-pointindicator.The L-dopa contents of tablets and capsules have been determined byusing these techniques and the assay results have been compared with thoseobtained by alternative methods, namely, the recently described B.P.pro-cedure involving non-aqueous titration, and ultraviolet spectrophotometry.Magnesium stearate, which is used as a lubricant and flow promoterin tablet manufacture, is titrated as a base in the solvents used, but in titra-tions of the acidic function of catecholamines its effect is negligible.E. J. GREENHOW and L.E. SPENCERDepartment of Chemistry, Chelsea College, University of London, Manresa Road,London, S.W.3.Analyst, 1973, 98, 485-492.The Determination of Di-n-alkyl Phthalates in CosmeticPreparations by Gas - Liquid ChromatographyAn improved gas-chromatographic method for the direct determination ofC,-C, di-n-alkyl phthalates in toiletry samples that contain ethanol is des-cribed and a range of perfume essential oils and perfume synthetic chemicalsis examined for possible interference.E. W. GODLY and A. E. MORTLOCKDepartment of Trade and Industry, Laboratory of the Government Chemist, CornwallHouse, Stamford Street, London, SE1 9NQ.Analyst, 1973, 98, 493-501.Residues of Prophylactics in Animal ProductsPart 111. The Determination of Carbarsone in Poultry MeatA method for the determination of carbarsone in poultry meat is de-scribed.The carbarsone is extracted from the sample with methanol and,after clean-up on an ion-exchange column, hydrolysed to arsanilic acid withsodium hydroxide. The arsanilic acid is diazotised, coupled with 2-amino-ethyl-1-naphthylamine and determined spectrophotometrically.R. A. HOODLESS and K. R. TARRANTDepartment of Trade and Industry, Laboratory of the Government Chemist,Cornwall House, Stamford Street, London, SE1 9NQ.Analyst, 1973, 98, 502-505July, 19731 SUMMARIES OF PAPERS I N THIS ISSUEThe Determination of Microgram Amounts of Sulphate byEmission Spectroscopy of Barium with a NitrousOxide - Acetylene FlameThe sulphate content of aqueous solutions has been determined in-directly, in the ranges 0-5 to 5.0 and 1.0 to 10.0 p.p.m.from barium emissionmeasurements. By using a slight excess of barium, the sulphate is precipi-tated in a 50 per cent. solution of propan-2-01 and its concentration is calcu-lated from the decrease in the barium content of the solution. The amountof barium in solution is determined from its emission a t 553-55 nm in a nitrousoxide - acetylene flame. The only major flame interference detected is thatfrom the band emission of calcium; 410 p.p.m. of calcium gave an emissionintensity equal to that of 1 p.p.m. of barium. Sulphate has been determinedin both pure solutions and in synthetic sample solutions containing otherelectrolytes. Major interferences were noted for potassium and ammoniumoxalate, sodium orthovanadate, nickel chloride and to a lesser extent forsodium fluoride and perchloric acid.The sulphur content of biologicalmaterial, digested by oxygen-flask combustion, has been determined satis-factorily by using this method.E. A. FORBESRuakura Soil Research Station, Private Bag, Hamilton, New Zealand.Analyst, 1973, 98, 506-51 1.Pyridylazonaphthols (PANs) and Pyridylazophenols (PAPs) asAnalytical ReagentsTheir Determination in AlloysThe reactions between copper(I1) and 2-(2-pyridylazo)-l-naphthol(0-a-PAN) and 4- (2-pyridy1azo)phenol ($-PAP) have been studied by spectro-photometry and graphical analysis, and their equilibrium constants havebeen determined. A rapid and simple method for the spectrophotometricdetermination of copper in aluminium alloys has been devised.A solutionof the alloy with pH 2 is extracted with an equal volume of a 5 x Msolution of o-a-PAN in carbon tetrachloride and the absorbance of the extractis measured at 590nm. The method has been checked by the analysis ofstandard alloys. The effect of interferences is discussed. The extractionbehaviour of several cations with o-%-PAN is discussed and the sequentialseparation of copper(II), zinc(II), manganese(I1) and lead(I1) is outlined.D. BETTERIDGE, D. JOHN and F. SNAPEChemistry Department, University College of Swansea, Swansea, Glarnorgan,SA2 8PP.Analyst, 1973, 98, 512-519.Part 111. Formation of Copper(I1) Complexes andPyridylazonaphthols (PANs) and Pyridylazophenols (PAPs) asAnalytical ReagentsPart IV. Formation of Complexes with Titanium(1V)The formation of complexes of titanium(1V) with PANs and PAPs hasbeen investigated in order to ascertain the types of complexes that areformed and to elucidate the optical and stability constants of such complexes.The competing effect of hydrolysis on these reactions has also been con-sidered. The reaction with 2-(2-pyridylazo)-l-naphthol (0-a-PAN) has beenexamined in order to determine the analytical utility of this complex formation.D. BETTERIDGE, D. JOHN and F. SNAPEviiChemistry Department, University College of Swansea, Swansea, Glamorgan,SA2 8PP.Analyst, 1973, 98, 520-524