ANALAO 1 16(8) 773-880 (1 991 )The AnalystAugust 1991The Analytical Journal of The Royal Society of ChemistryCONTENTS773 Evaluation of a Rapid Technique for the Determination of Precious Metals in Geological Samples Based on a Selective781 Compensation for Particle Size Effects in Near Infrared ReflectanceChristine R. Bull787 Immunocomplex-immobilization Technique-Sven Oscarsson, Jan Carlsson793 Immobilized-enzyme Electrode for Nicotinamide Adenine Dinucleotide (Reduced Form) (NADH) Sensing andApplication t o the Kinetic Studies of NADH Dependent Dehydrogenases-Hsien-Chang Chang, Akinori Ueno,Hiroshi Yamada, Tomokazu Matsue, lsamu Uchida797 Amperometric Monitoring of Sulphur Dioxide in Liquid and Air Samples of Low Conductivity by Electrodes Supportedon lon-exchange Membranes-Gilbert0 Schiavon, Gianni Zotti, Rosanna Toniolo, Gin0 Bontempelli803 Voltammetric Behaviour of Salicylic Acid at a Glassy Carbon Electrode and Its Determination in Serum Using LiquidChromatography With Amperometric Detection-Denley Evans, John P.Hart, Glan Rees807 Improvement on the Microdiffusion Technique for the Determination of Ionic and Ionizable Fluoride in Cows'Milk-Jacobus F. van Staden, Sophia D. Janse van Rensburg81 1 lndomethacin lon-selective Electrode Based on a Bis(triphenylphosphoranylidene)ammonium-lndomethacinComplex--Ralph Aubeck, Christoph Brauchle, Norbert Hampp815 Column Preconcentration of Trace Metals From Sea-water With Macroporous Resins Impregnated With LipophilicTetraaza Macrocycles-Stephane Blain, Pierre Appriou, Henri Handel821 Determination of Trace Amounts of Tellurium by the Sub-superequivalence Method of Isotope DilutionAnalysis-H i roe Yos h io ka, Yos h i no ri Mi ya ki, Ku ni h i ko H asegawa825 Separation and Determination of Trace Amounts of Cadmium by On-line Enrichment in Flow Injection Flame AtomicAbsorption Spectrometry-Rajesh Pu roh it, Su rekha Devi831 Flow Injection Sample-to-standard Additions Method Using Atomic Absorption Spectrometry Applicable t oSlurries-I g n a ci o Lopez G a rcia, Fra nci sca 0 rt iz So beja n 0, Ma n u e I Her n a n d ez Co rdo ba835 Flow Analysis Method for the Determination of Silicic Acid in Highly Purified Water by Gel-phase Absorptiometry WithMolybdate and Malachite Green-Kazuhisa Yoshimura, Ushio Hase841 Differential Conductimetry in Flow Injection.Determination of Ammonia in Kjeldahl Digests-Jarbas Jose RodriguesRohwedder, Celio Pasquini847 Determination of the Platinum, Rhenium and Chlorine Contents of Alumina-based Catalysts by X-ray FluorescenceSpectrometry-Rao V. C. Peddy, G. Kalpana, ValSamma J. Koshy, N. V. R. Apparao, M. C. Jain, R. V. Patel851 Determination of the Insecticide Promecarb by Fluorogenic Labelling With Dansyl Chloride-F. Garcia Sanchez, C.Cruces Blanco857 Determination of Epinephrine, Norepinephrine, Dopamine and L-Dopa in Pharmaceuticals by a PhotokineticMethod-Carmen Martinez-Lozano, Tomas Perez-Ruiz, Virginia Tomas, Otilia Val861 Selective Spectrophotometric Method for the Determination of Ascorbic Acid in Pharmaceutical Preparations andFresh Fruit Juices-Enaam Y. Backheet, Kamla M. Emara, Hassan F. Askal, Gamal A. Saleh867 Colorimetric Method for the Determination of Captafol (Difolatan) in Commercial Formulations and Residues on Grainsand Apples-Balbir C. Verma, Devender K. Sharma, Hari K. Thaku, Bh. Gopal Rao, Narendra K. Sharma871 Determination of Atmospheric Sulphur Dioxide by Solid-phase Spectrophotometry-Juan M. Bosque-Sendra,Francisca Molina, Eugenia Lopez875 BOOK REVIEWS879 CUMULATIVE AUTHOR INDEXAqua Regia Leach-Charles J. 6. Gowing, Philip J. PottsTypeset and printed by Black Bear Press Limited, Cambridge, Englan