Voltammetric determination of 4-nitrophenol at a sodium montmorillonite-anthraquinone chemically modified glassy carbon electrode

A new method for the determination of 4-nitrophefiol(4-NP) by differential pulse voltammetry (DPV) based on adsorptive stripping technique was describ ed. Cyclic voltammetry (CV) and linear scan voltammetry (LSV) were used in a comparative investigation into the electrochemical reduction of 4-NP at a Na-montmorillonite(SWy-2) and anthraquione (AQ) modified glassy carbon ele ctrode. With this chemically modified electrode, 4-NP was first irreversibl y reduced from phi NO2 to phi NHOH at - 0.78 V. A couple of well-defined re dox peaks at + 0.22 V (vs. SCE) were responsible for a two-electron redox p eak between phi NHOH and phi NO. Studies on the effect of pH on the peak he ight and peak potential were carried out over the pH range 2.0-9.0 with the phosphate buffer solution. A pH of 3.4 was chosen as the optimum pH. The o ther experimental parameters, such as film thickness, accumulation time and potential etc. were optimized. Anodic peak currents were found to be linea rly related to concentration of 4-NP over the range 0.3-45 mg l(-1), with a detection limit of 0.02 mg l(-1). The interference of organic and inorgani c species on the voltammetric response have been studied. This modified ele ctrode can be used to the determination of 4-NP in water samples. (C) 2001 Elsevier Science B.V. All rights reserved.