Anodic Stripping Voltammetric Determination of Thallium(III) Using a Tosflex/Mercury Film Electrode

Abstract

A Tosflex/mercury film electrode (TMFE) was prepared by spin-coating a solution of the perfluorinated anion exchange polymer Tosflex onto a glassy carbon electrode surface followed by electrodeposition of a mercury film on this electrode. This electrode was used for the determination of trace thallium(III) which was preconcentrated onto the TMFE as the [TlCl4]− anion in a chloride medium by the anion-exchange feature of Tosflex and then determined by anodic square-wave stripping voltammetry (SWSV). Various parameters influencing the determination of thallium(III) were examined in detail. With 1 min accumulation, the analytical signal versus concentration dependence was linear from 0 to 80 ppb, and the detection limit was 0.1 ppb. The modified electrode showed good resistance to interferences from surface-active compounds and common ions. For repetitive use, the TMFE surface could be easily regenerated by setting the electrode potential at −0.4 V for 30 s.