Sensitive Voltammetric Detection of Metol with a TiO2 Nanowire Modified Carbon Ionic Liquid Electrode

Abstract

In this work a TiO2 nanowire modified carbon ionic liquid electrode (CILE) was constructed and used for the sensitive electrochemical detection of metol. Electrochemical performances of the modified electrode were investigated by the classical techniques including cyclic voltammetry and electrochemical impedance spectroscopy, which indicated that the presence of TiO2 nanowire on the CILE surface could greatly improve the electrochemical signal. Electrochemical behaviors of metol were further studied on TiO2/CILE and the appearance of a pair of well-defined redox peaks indicated the excellent electrocatalytic activity. Electrochemical parameters of the electrode reaction of metol, including the electron transfer coefficient (α), the electron transfer number (n) and the heterogeneous electron transfer kinetic constant (ks), were obtained as 0.46, 1.8, 1.48 s-1, respectively. On the modified electerode the oxidation peak currents of metol increased proportional with the concentration in the range of 0.08 μmol L-1~ 800.0 μmol L-1 accompanied by a detection limit of 0.0237 μmol L-1 (3σ). Moreover, the analytical performance of the proposed method for artificial water samples was evaluated with good sensitivity and acceptable recoveries.