ANALAO 104 (1 235) 97-1 76 (1 979)ISSN 0003-2654February 197997106111117124136143146148151154156160164167172174176THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICAL SOCIETYCONTENTSSub-micrometre Particle Size Characterisation and Distribution by MercuryPenetration-Nayland G. Stanley-WoodDetermination o f Acrylonitrile Monomer in Plastic Packaging and Beveragesby Headspace Gas Chromatography-G. B.-M. GawellDetermination o f Ethylenethiourea in Ethylenebisdithiocarbamate Fungicides:Comparison o f High-performance Liquid Chromatography and Gas - LiquidChromatography-D. S. Farrington and R. G. HopkinsFluorimetric Determination o f Acetohexamide in Plasma and Tablet Formula-tions Using 1 -Methylnicotinamide-Pamela Girgis-Takla and loannis ChroneosPolarographic Determination o f Trace Elements in Food from a Single Digest-M.Kapel and M. E. KomaitisApparatus f o r the Automatic Preparation of Soil Extracts for Mineral-nitrogenDetermination-J. A. P. Marsh, R. Kibble-White and C. J. StentSHORT PAPERSSpectrophotometric Determination o f Dequalinium Chloride in PharmaceuticalPreparations-C. P. Leung and S. Y. KwanSpectrophotometric Determination o f lsoprenaline Sulphate and MethyldopaUsing Chloranil-Mohamed A. Korany and Abdel-Aziz M. WahbiSpectrophotometric Determination of Microgram Amounts o f Hydroquinone,Pyrogallol and Resorcinol-Q. S. Usmani, M. M. Beg and I. C. ShuklaSimple Procedure for the Determination o f Total Carbon and i t s Radioactivityin Soils and Plant Materials-R.C. DalalDetermination of Lead in Columbite Concentrates by Atomic-absorptionSpectrometry After Sulphide Separation-C. ChowDirect Determination of Calcium, Magnesium and Zinc in Lubricating Oils andAdditives by Atomic-absorption Spectrometry Using a Mixed SolventSystem-Zsuzsa WittmannSpectrophotometric Determination of Iron by Synergistic Extraction withlsonitrosobenzoylacetone and Pyridine-B. J. Desai and V. M. ShindePotentiometric Method for the Rapid Determination o f Sulphate in the Presenceo f Chromi um (VI)-R. PrasadDetermination of Thiocyanates by Thermal Decomposition o f Silver Thio-cyanate-A. Cygahski and T. MajewskiCO M M U N ICATIONSelective Determination o f Arsenic(ll1) and Arsenic(V) by Atomic-absorptionBook ReviewsErratumSpectrophotometry Following Arsine Generation-Susumu NakashimaSummaries of Papers in this Issue-Pages iii, iv, v, v iPrinted by Heffers Printers Ltd Cambridge EnglandEntered as Second Class at New York, USA, Post Offic