RESUMO
The cyclic voltammetric behaviors of sodium selenite on the gold electrode modified by L-cysteine self-assembled monolayer (L-Syc,Au/SAMs) has been investigated in 0.05 mol/L H_2SO_4 solutions with sodium selenite. Sensitive anodic stripping current of selenium (Se) with the peak potential at 0.99 V (vs. SCE) has been observed. In comparison with the electrochemical properties of sodium selenite on the modified electrode with those on the naked gold electrode, it was found that selenite was reduced to selenium by the redox interaction with sulfur on the monolayer and the monolayer catalytically oxidizes Se as the electrode was positively scanned. According to the electrochemical properties of sodium selenite both on the naked and modified gold electrode, the Se deposition mechanism and catalytic mechanism as well as bionic membrane model were proposed for the bio-utilization of selenite through nano scale selenium.
