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A fast and convenient analytical technique has been suggested to detect dihydroxybenzene (DHB) isomers directly and simultaneously. In 0.1 M HAc-NaAc buffer solution (pH 5.6), the reduction peaks of p -DHB and o -DHB were partly separated by differential pulse voltammetry at the glassy carbon electrode. By adding a surfactant (cetyl pyridinium chloride) to enhance the detection sensitivity and using a semi-derivative technique to improve the separation, p-DHB and o-DHB were detected simultaneously. The linear calibration ranges were 1.2 × 10−6 to 1.0 × 10−4 M for p -DHB and 8.2 × 10−7 to 1.0 × 10−4 M for o -DHB, with detection limits of 3.6 × 10−7 and 2.4 × 10−7 M, respectively. The proposed method has been applied to the direct determination of DHB isomers in water sample, and the results were excellent.

This paper has adopted a fast and convenient analytical technique to detect dinitrophenol isomers directly and simultaneously. In 0.1 mol L −1 HAc–NaAc buffer solution (pH 5.8), 2,4- and 2,5-dinitrophenol exhibited good resolution by DPV at the GC electrode. By using the surfactant of cetyl trimethyl ammonium bromide, the reduction peaks currents were enhanced and the detection sensitivity was improved dramatically. The action mechanism was investigated in detail and some valuable message has been found. The linear calibration ranges from 1.0 × 10 −6 to 8.0 × 10 −4 mol L −1 for both 2,4- and 2,5-dinitrophenol, with detection limits of 2.4 × 10 −7 for 2,4- and 1.5 × 10 −7 mol L −1 for 2,5-dinitrophenol. This method was applied in the determination of dinitrophenol isomers in model water sample, and the recovery was from 98% to 103%.