Voltammetric response of glutathione and 3-mercaptopropionic acid self-assembled monolayer modified gold electrodes to Cu(II)

Glutathione (GSH) self-assembled monolayer (SAM) is prepared on a gold electrode, It has been found that the modified electrode exhibits selective response to cupric ions, and the Cu(II) wave appears at about 0.3 V (vs. SCE), Conditions of determination are optimized, including parameters that govern the sensitivity and selectivity of this system. When the gold electrode is modified with the mixture of GSH and 3-mercaptopropionic acid (3MPA). the resulting SAMs modified electrode shows better sensitivity and selectivity for Cu(II) compared with GSH SAM modified gold electrode. Under optimal conditions, the anodic wave height is linear to Cu(II) in the range of ca. 10 muM to 0.1 mM without preconcentration. The influence of various factors and related mechanism is discussed. The organic monolayer modified electrode is stable and simple to prepare.