The determination of thallium in environmental and biological samples is of great interest because of high toxicity of its compounds[1]. Vapour generation techniques in atomic absorption spectrometry (cold vapour or hydride generation techniques) are very popular because of enhanced concentration detection limits compared to conventional nebulization sample into a given atom reservoir. Additionally, isolation and chemical separation of the analyte from the matrix could be achieved[2]. However, thallium vapour generation, presumably as hydride, is less sensitive than conventional FAAS whilst subject to large positive interferences from the presence of other covalent hydride forming element. For this reason this method remained more than a curiosity [3]. Recently, EcHg is used as an alternative approach to the original chemical generation technique (CHG), which presents several advantages in hydride generation procedure [4,5]. This research reports improvement in thallium hydride generation by using electrochemical hydride generation AAS system instead of conventional chemical hydride generation AAS technique using tetrahydroborate and its derivatives. In this system thallium hydride was generated in a semi-batch electrolytic cell at constant applied current and transferred to a heated quartz tube atomizer (QTA) which was placed at light beam of atomic absorption spectrometer and the absorbance was measured. The influence of electrode type (Sn-Pb alloy, graphite electrode and dental amalgam electrode), catholyte solution and its concentration (hydrochloric acid, nitric acid and sulfuric acid), anolyte solution and its concentration ( acidic and basic electrolyte solution), current density and carrier gas flow rate were discussed and optimum conditions were obtained using Sn-Pb alloy electrode, hydrochloric acid as catholyte and sodium carbonate as anolyte solution. Statistical parameters and calibration curve also were obtained. Potential interferences and application of the method to environmental and biological samples was discussed.

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