Electrocatalytic Oxidation of Hydroquinone at Poly(crystal-violet) Film–Modified Electrode and Its Selective Determination in the Presence of o-Hydroquinone and m-Hydroquinone

A stable poly(crystal-violet) (PCV) electroactive film was electrodeposited on a glassy carbon electrode (GCE). The redoxation of hydroquinone showed a pair of well-defined peaks on a PCV electrode with a potential difference of 30 mV, which is 120 mV less than that obtained on the GCE. At optimal conditions, the PCV electrode linearly responded to the hydroquinone in the range of 4 × 10−6 mol · L−1 to 3.2 × 10−3 mol · L−1 and a detection limit of 8 × 10−8 mol · L−1 was obtained. The separations of the oxidation peak potentials between hydroquinone and the coexisting o-hydroquinone and m-hydroquinonewere 100 mV and 430 mV, respectively, which allows their simultaneous determination. The detection of hydroquinone in artificial sewage water was demonstrated with satisfactory results.