In this research, electrochemical hydride generation of thallium species (Tl(I) and Tl(III)) have been considered in various cathodic conditions. A simple catholyte variation batch hydride generation system has been used for production of thallium hydrides which are detected subsequently by an atomic absorption spectrometer. Some critical parameters that seems to be effective on Tl(I) and Tl(III) signals are considered and investigated thoroughly. These conditions include: electrode (cathode material) type, catholyte (solvent) medium, supporting electrolyte type, and application a presaparation step. Cathode type (Pb-Sn, Sn, Pb, Hg amalgam, Pt, and Graphite), solvent type (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2- butanol, acetonitrile, dimethylsulfoxide, dimethylformamide, and ethyl acetate) and catholyte supporting electrolyte (Cl-, EDTA) proved to be ineffective in speciation analysis. Speciation analysis of Tl(I) and Tl(III) by electrochemical hydride generation-atomic absorption spectrometry is only possible using a pre-separation step. A simple on-line column sepration using amberlite IRC-718 chelating resin (including iminodiacetic acid active functional group) is recommended and used. Separation of the two species was performed in different working pHs.

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