60N JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY OCTOBER 1993 VOL. 8 Future Issues will Include Use of Palladium as a Chemical Modi- fier for the Determination of Silicon by Electrothermal Atomic Absorption Spectrometry-Zhi-xia Zhuang Peng- yuan Yang Xiaru Wang Zhiwei Deng and Benli Huang Determination of Palladium ad Plati- num in Freshwaters by Inductively Coupled Plasma Mass Spectrometry and Activated Charcoal Preconcentra- tion-Gwendy E. M. Hall and J. C. Pelchat Improvement in Mercury Cold Va- pour Atomic Techniques by Resorting to Organized Assemblies and On-line Membrane Drying of Vapour-B. Aizpun Fernandez M. R. Fernandez de la Campa and Alfredo Sanz-Medel Indirect Atomic Absorption Spectro- metric Determination of Papaverine Strychnine and Cocaine by Continu- ous Precipitation With Dragendorff's Reagent-Marcelina Eisman Mer- cedes Gallego and Miguel Valcarcel Determination of Ultratrace Levels of Heavy Metals in Polar Snow by Elec- trothermal Vaporization Inductively Coupled Plasma Mass Spectro- metry-Ralph E.Sturgeon S. N. Willie and D. Conrad Gregoire Speciation of Arsenic by Ion Chro- matography and Off-line Hydride Generation Electrothermal Atomic Absorption Spect romet ry-Heng-bin Han Yan-bing Liu Zhe-ming Ni and Shi-fen Mai Arsenic Speciation in Seafood Samples with Emphasis on Minor Constituents. An Investigation by High-performance Liquid Chromatography With Induc- tively Coupled Plasma Mass Spectro- metric Detection-Gunnar Pritzl and Steen H. Hansen Effect of Aqeuous-Organic Solvents on the Determination of Trace Elements by Atomic Absorption Spectrometry and Inductively Coupled Plasma Atomic Emission Spectrometry-M. Todorovic S. Vidovic and Z. Ilic Electrothermal Vaporization for Sample Introduction in Microwave- induced Plasma Atomic Absorption Spectrometry-Yi-xiang Duan Xing- you Li and Qin-han Jin Improvement in Detection Limits in Graphite Furnace Diode Laser Atomic Absorption Spectrometry by a Wave- length Modulation Technique-Chris- toph Schnurer-Patschan Aleksandr Zy- bin Henning Groll and Kay Niemax Determination of Selenium in Marine Certified Reference Materials by Hy- dride Generation Inductively Coupled Plasma Mass Spectrometry-Hiroaki Tao Joseph W. Lam J. W. McLaren Atomic Spectrometry Update The Update in the December issue is-Industrial Analysis Metals Chemicals and Advanced Materials- John Marshall John Carroll James S. Crighton and Charles L. R. Barnard