ANALAO 104 (1 240) 593-704 (1 979)ISSN 0003-2654July 1979THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICAL SOCIETYCONTENTS593601Simplification of the Mathematical Evaluation of Titration Results by RegardingComplexes of the Type A,B as n Complexes of the Type AB-Sten JohanssonAutomatic Titration by Stepwise Addition of Equal Volumes o f Titrant. Part IV.General-purpose Program for Evaluating Potentiometric Acid - BaseTitrations-Axel Johansson and Sten JohanssonPyridine-2-carbaldehyde 2-Hydroxybenzoylhydrazone as a Selective Reagent forthe Extraction and Spectrophotometric Determination of lron(l1)-M.Gallego, M. Garcia-Vargas and M. Valcarcel620 S pect r o p hotomet r i c Determination of Aceta m i no p hen, Sa I i cy I a m i d e andCodeine Phosphate in Tablets-M.Abdel-Hady Elsayed, Saied F. Belal, Abdel-Fattah M. Elwalily and Hassan Abdine626 Determination of Vitamin D2 in Multivitamin Tablets by High-performanceLiquid Chromatography-Christeen Mackay, J. Tillman and D. Thorburn Burns637 Modified Fluorimetric Procedure for the Simultaneous Determination o fThiamin and Riboflavin i n Cowpea-J. K. Edijala645 Determination of Noble Metals by Carbon Furnace Atomic-absorption Spectro-metry. Part I. Atom Formation Processes-W. B. Rowston and J. M.Ottaway660 Separation of Organotin Compounds by Using the Difference i n PartitionBehaviour Between Hexane and Methanolic Buffer Solution. Part 1.Determination of Butyltin Compounds i n Textiles by Graphite FurnaceAtomic-absorption Spectrophotometry-Shigeo KojimaMethod for the Rapid Detection o f Organic Pollutants i n Water by Vapour-phase Ultraviolet Absorption Spectrometry-K.C. Thompson and K. Wagstaff61 3668SHORT PAPERS680 Cathode-ray Polarographic Determination of Molybdenum in Serum, Plasmaand Urine-Gary D. Christian and Gaston J. Patriarche683 Improved Method for the Determination of Mercury in Fish Tissue Using 50%Hydrogen Peroxide and a Hot Block-J. W. Davidson687 Preparation and Operation of Selenium Electrodeless Discharge Lamps for Usei n Atomic-fluorescence Flame Spectrometry-R. G. Michel, J. M. Ottaway,J. Sneddon and G. S. Felllodimetric Determination of Milligram Amounts of Certain Aliphatic Acids-S. N. Nema and R. M. VermaA Variation of the Monier-Williams Distillation Technique for the Determinationof Sulphur Dioxide i n Ginger Ale-Bronislaw L. Wedzicha and Michael K.Johnson691694C 0 M M U N I CAT1 0 N S696 Sources of Error in the Flame Photometric Determination o f Sodium and698 Gas Analysis Using an Internal Standard in Adsorption Tubes-B. I. Brookes700 Book ReviewsPotassium in Portland Cements-P. G. Deane and T. P. LeesSummaries o f Papers in this Issue-Pages iv, v, vii, x, xii, x i i iPrinted by Heffers Printers Ltd Cambridge EnglandEntered as Second Class at New York, USA, Post Offic