VOLTAMMETRIC DETERMINATION OF 2-NITROPHENOL AT A BENTONITE-MODIFIED CARBON-PASTE ELECTRODE

A bentonite-modified carbon paste electrode has been applied to the de termination of 2-nitrophenol by differential pulse voltammmetry. The e lectrochemical reduction of 2-nitrophenol at - 0.8 V is carried out in an artificial sea water-formic acid/sodium formate medium at pH 4. Th e peak height was found to be dependent on the pH over the range 2-11; the presence of a secondary process was observed in the pH range 8-11 . The peak potential showed a dependence on pH, with two linear region s with different slopes. A. linear relationship between peak intensity and concentration was obtained in the range 0.07-10 mg l(-1), with a detection limit of 0.03 mg l(-1) and a coefficient of variation of 1.3 % at 5 mg l(-1). The effects of organic and inorganic species on the 2 -nitrophenol determination were studied with a view to testing the res olution of the voltammetric technique. The proposed method has been ap plied to sea water samples with good results.