Electrolytic hydride generation atomic absorption spectrometry for the determination of antimony, arsenic, selenium, and tin - mechanistic aspects and figures of merit

This article deals with the electrocatalytic and electrochemical mechanisms of hydride formation and their dependence on hydrogen overvoltage. A three -electrode-arrangement was used to determine the hydrogen overvoltage of di fferent cathode materials (Pt, Au, Ag, glassy carbon, Cd, Pb, amalgamated A g). The applicability of these cathode materials was tested for hydride for mation using As(III), As(V), Sb(III), Sb(V), Se(IV), and Sn(IV). Glassy car bon is the most suitable cathode material for hydride generation with As(II I), Sb(III), Se(IV), and Sn(IV). Hg-Ag is well suited for the production of stibine and arsine. As(III), As(V), Sb(III), and Sb(V) were all converted into their hydrides with efficiencies > 90%. A detection limit in the range of 0.11-0.13 mug L-1 for As and Sb (sample volume 200 muL) was obtained fo r cathode materials with a high hydrogen overvoltage. The precision of repl icate measurements was better than 5% calculated as variation coefficient. The accuracy of the presented method was verified by analysis of certified reference materials and tissues of cancer patients. The recovery rates for As and Se were calculated to be 93-108%.