Electro-Oxidation of Nitrite Using an Oxidized Glassy Carbon Electrode as Amperometric Sensor

In this work, a simple and innovative method is proposed to get an active glassy carbon electrode (GC) toward nitrite oxidation. The oxidation method was based on an anodic treatment, through a time-and potential-controlled electrolysis, in NaOH 0.1 M. This treatment increased the activity in all pH values that were studied, being the pH 8.0 as the best one. It was possible to calculate the kinetic parameters, where the number of transferred electrons calculated was one, and Tafel slope was 70 mV per decade. With these values, a reaction mechanism was postulated. At the best experimental conditions, the electrode has a good behavior as an amperometric sensor versus nitrite oxidation. The system follows linearity in all the range of concentrations and allowed the calculation of analytical parameters such as detection limit, quantification limit, accuracy, and exactitude. Good results were obtained at this point, so the system might be considered a good method for nitrite determination and quantification in aqueous solutions.