Derivative voltammetric direct simultaneous determination of nitrophenol isomers at a carbon nanotube modified electrode

Cyclic voltammetry was used to investigate the electrochemical reduction of nitrophenol isomers at a glassy carbon electrode modified with carbon nanotubes, and a derivative voltammetric technique was adopted to improve the resolution and enhance the determination sensitivity. In 0.1 mol L−1 HAc–NaAc buffer solution (pH 5.0), the modified electrode showed a good electrocatalytic response towards nitrophenol isomers. Through a derivative technique, the peak currents increased significantly and the reduction peaks of nitrophenol isomers could be separated, so the method could be applied to direct simultaneous determination without preseparation. The linear calibration ranges were 4.0 × 10−6 to 2.0 × 10−3 mol L−1 for o-nitrophenol, 1.0 × 10−5 to 1.0 × 10−3 mol L−1 for m-nitrophenol and 2 × 10−6 to 4.0 × 10−3 mol L−1 for p-nitrophenol, with detection limits of 5.0 × 10−7, 6.0 × 10−6 and 4.0 × 10−7 mol L−1, respectively.