A sensitive hydrazine hydrate sensor based on a mercaptomethyl-terminated trinuclear Ni(II) complex modified gold electrode

In this study, a novel mercapto-terminated trinuclear Ni(II) complex (Ni-3) was synthesized and used as an electrocatalyst for the detection of hydrazine hydrate in real water samples. The as-prepared Ni-3 molecule possesses six thiomethyl groups at its periphery and these SCH3 groups can react with Au electrodes to immobilize the Ni-3 molecules on their surface through the formation of a self-assembled monolayer. The Ni-3-modified Au electrode (Ni-3/Au) demonstrates excellent electrocatalytic activity for the oxidation of hydrazine hydrate through a significant decrease in overpotential. The chronoamperometry study shows a diffusion coefficient (D) of 5.82 x 10(-5) cm(2) s(-1) and a catalytic rate constant of 8.57 x 10(3) M-1 s(-1). Using the square wave voltammetry (SWV) technique, this Ni-3/Au electrode based hydrazine hydrate sensor exhibits a high sensitivity in quantitative analysis, and its detection limit could be as low as similar to 0.07 mu M with linearity ranging from 0.2 to 50 mu M. In addition, due its good reproducibility, anti-interference performance, and long-term stability, the proposed sensor is capable of detecting trace levels of hydrazine hydrate in real water samples.