Electrochemical behaviors of metol on hydrophilic ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate-modified electrode

In this paper a hydrophilic ionic liquid of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) was used as modifier to make a new kind of ionic liquid-modified carbon paste electrode (IL-CPE), which was further characterized by different methods including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscope (SEM). The fabricated IL-CPE showed good electrocatalytic behaviors towards the oxidation of metol with the enhancement of the redox peak current and the decrease of the peak-to-peak separation. The electrochemical behaviors of metol on the IL-CPE were carefully studied and the electrochemical parameters were calculated. Based on the electrocatalytic reaction, a new electrochemical method for the metol determination was established in the concentration range from 4.0 × 10−6 to 5.0 × 10−3 mol L−1 by cyclic voltammetry with the detection limit estimated to be 2.0 × 10−6 mol L−1 (3σ). The established method was successfully applied to the synthetic samples and photographic solutions detection with good recovery.