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 X 10(-6) to 8.0 X 10(-4) mol L-1 for both 2,4- and 2,5-dinitrophenol, with detection limits of 2.4 x 10(-7) for 2,4- and 1.5 x 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%. (c) 2006 Elsevier Ltd. All rights reserved.