Electrochemical behaviors of hydroquinone on a carbon paste electrode with ionic liquid as binder

In this paper the electrochemical behaviors of hydroquinone (H(2)Q) were investigated on a carbon paste electrode using room temperature ionic liquid N-butylpyridinium hexafluorophosphate (BPPF6) as binder (IL-CPE) and further applied to H(2)Q determination. In pH 2.5 phosphate buffer solution (PBS), the electrochemical response of H(2)Q was greatly improved on the IL-CPE with a pair of well-defined quasi-reversible redox peaks appeared, which was attributed to the electrocatalytic activity of IL-CPE to the H(2)Q. The redox peak potentials were located at 0.340 V (Epa) and 0.240 V (Epc) (vs. the saturated calomel electrode, SCE), respectively. The formal potential (E-0') was calculated as 0.290 V and the peak-to-peak separation (Delta E-P) was 0.100 V. The electrochemical parameters of H(2)Q on the IL-CPE were further calculated by cyclic voltammetry. Under the selected conditions the anodic peak current was linear with H(2)Q concentration over the range from 5.0 x 10(-6) to 5.0 x 10(-3) mol L-1 with the detection limit as 2.5 x 10(-6) mol L-1 (3 sigma) by cyclic voltammetry. The proposed method was successful applied to determination of H(2)Q content in a synthetic wastewater sample without the interferences of commonly coexisting substances.