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A simple Spectrophotometric method was optimized for the Speciation vanadium using pyrocatechol violet as chelating agent. Uanadium(V) was determined by pyrocatechol violet at pH 3.0, whereas vanadium(IV) was simultaneously determined using same procedure after oxidation of vanadium(IV) by potassium permanganate. The linear range for vanadium(V) is 0.2–4.0 μg/mL with a detection limit of 0.038 μg/mL. The proposed Spectrophotometric method was found selective for vanadium(V) with high tolerence limit of foreign ions. The proposed method was validated by standard addition method at different levels of both understudied species with >92 %recoveries in water, black pepper and coal samples.

Ethanol oxidation wasstudied on single-crystalAu(111) electrodes that weremodified byplatinum, palla-dium, and cadmium metal ad-layers. The metal ad-layer modification was carried out by the underpotentialdeposition process, in which controlled amounts of Pt, Pd, and Cd were electrodeposited onto the substrateas submonolayer or monolayer coverage. The activity of the metal ad-layer modified Au(111) electrodestoward ethanol oxidation was studied in alkaline media, and recorded voltammograms were compared tothose of bare single crystal Au(111) and polycrystalline gold and platinum disk electrodes. In terms ofthe desired shift in reduction potential and increased current density, the best electrocatalytic activity wasobtained with a 30-s electrodeposited Pt ad-layer modified Au(111) electrode.Key Words: Ethanol oxidation, Pt ad-layer, Pd ad-layer, Cd ad-layer, Au(111) single crystal electrode,fuel cell, catalyst

A solid phase extraction method for the determination of gold(III) at trace levels by flame atomic absorption spectrometer (FAAS) was developed. The method was based on retention of gold as chloro complexes through the Amberlite XAD-2000. The effect of some analytical parameters including hydrochloric acid concentration, sample volume, sample and eluent flow rates, eluent volume, eluent concentration and interfering ions on the recovery of gold(III) was investigated. The retention of gold(III) from 1.5 mol l-1 HCl solution and the recovery of gold with 0.07 mol l-1 NH3 solution were quantitative (?95%). The relative standard deviation (RSD) was calculated as 3.2% (n=10). The detection limit for gold was 2 µg l-1. The accuracy was checked with the determination of gold spiked an artificial seawater and a pure copper samples. © Springer Science + Business Media B.V. 2007.