Thallium has been found to be an environmentally hazardous element because of its toxic effects [1]. It is, therefore, important to detect and determine thallium in a wide range of matrices. Since the total concentration of thallium is generally very low, an analytical technique with high sensitivity and low detection limit is required. An electrochemical hydride generation (ECHG) technique had been developed to improve the determination of thallium by atomic spectrometry [2]. Although the method offers high sensitivity, simplicity, rapidness, freeness from reagent and low acid consumption, it suffers from high concomitant interferences, thus applicability of the method to some real samples, e.g. water, is limited. Electrochemical reactions are especially dependent to solvent. Using water soluble organic solvents will alter the electrochemical characteristics of the elements and overcomes this problem. In the present research attempts were done to study the effects of some organic solvents on the electrochemical hydride generation of thallium. In order to find most appropriate solvent, some organic solvents were used and their effects were studied. Parameters that might affect the electrochemical hydride generation efficiency were investigated and the analytical performance of the method under the optimized experimental conditions was assessed. The linear range were 1-200 ng mL-1 for thallium and the relative standard deviation of the method was 3% (RSD, n=7). The LOD for thallium was found to be 0.35 ng mL-1, showing improvement relative to aqueous electrochemical hydride generation technique. The proposed method was successfully applied to the determination of thallium in tap water.

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