12N Analyst, January 1994, Vol. 119 Future Issues will lnclude- On-line Chromium Determination by Adsorptive Cathodic Stripping Voltammetry-Andrew M. Dobney and Gillian M. Greenway Development of a Disposable Amperometric Sensor Based on a Chemically Modified Screen-printed Carbon Electrode for Reduced Nicotinamide Adenine Dinucleotide-Steven D. Sprules, John P. Hart, Stephen A. Wring and Robin Pittson Development of Amperometric Sensors for Uric Acid Based on Chemically Modified Graphite-Epoxy Resin and Screen- printed Electrodes Containing Cobalt Phthalocyanine- Markas A. T. Gilmartin, John P. Hart and Brian J. Birch Functionalized Cyclodextrins as Potentiometric Sensors for Onium Ions-Paul S. Bates, Ritu Kataky and David Parker Hand-held Instrumentation for Environmental Monitoring- Claudius D’Silva and Gwyn Williams Selective Membrane Electrodes for Analysis-J.D. R. Thomas Organic-phase Application of an Amperometric Glucose Sensor-Emmanuel I. Iwuoha and Malcolm R. Smyth Mathematical Model of Toxicity Monitoring Sensors Incor- porating Microbial Whole Cells-Barry G. D. Haggett Determination of Nitrate in Carbon Black by Using a Nitrate-selective Electrode-Ricardo Perez-Olmos, JosC M. Merino, Izaskun Ortiz de Zarate, JosC L. F. C. Lima and Conceiqao B. S. M. Montenegro Batch and Flow Determination of Uranium(v1) by Adsorptive Stripping Voltammetry on Mercury-film Electrodes- Anastasios Economou, P. R. Fielden and A. J. Packham Horseradish Peroxidase Assay-Radical Inactivation or Sub- strate Inhibition? Revision of the Catalytic Sequence Follow- ing Mass Spectrum Evidence-Ramin Pirzad, Antony A.Dowman and David C. Cowell Ionophore-Ionomer Films on Glassy Carbon Electrodes for Accumulation Voltammetry. Investigation of a Lead(rr) Iono- phore-Damien W. M. Arrigan, Gyula Svehla, John Alder- man and William A. Lane Simple Solid Wire Microdisc Electrodes for the Determina- tion of Vitamin C in Fruit Juices-Amiel M. Farrington, Nidhi Jagota and Jonathan M. Slater Prediction of Gas Sensor Response Using Basic Molecular Parameters-Jonathan M. Slater and J. Paynter Ion-selective Field-effect Transistor and Chalcogenide Glass Ion-selective Electrode Systems for Biological Investigations and Industrial Applications-Yuri G. Vlasov, Eugene A. Bychkov and Andrey V. Bratov Amperometric Biosensor for Phenols Based on a Tyrosinase- Graphite-Epoxy Resin Biocomposite-Joseph Wang, Fang Lu and David Lopez Determination of Ultra-trace Amounts of Selenium(1v) by Flow Injection Hydride Generation Atomic Absorption Spec- trometry With On-line Preconcentration by Coprecipitation With Lanthanum Hydroxide-Elo Harald Hansen and Guanhong Tao Electrochemical Immobilization of Enzymes.Part VI. Micro- electrodes for the Detection of L-Lactate Based on Flavo- cytochrome 6 2 Immobilized in a Poly(pheno1) Film-Philip N. Bartlett and Daren J. Caruana Dynamic Separation of Mobile Species Transfer Processes at Polymer Modified Electrodes Using the Electrochemical Quartz Crystal Microbalance-A. Robert Hillman, Noelle A. Hughes and Stanley Bruckenstein Advanced Electroanalytical Techniques versus Atomic Absorption Spectrometry, Inductively Coupled Plasma Atomic Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry in Environmental Analysis- Pierre M. Bersier, Jonathon Howell and Craig Bruntlett