Nimesulide Determination on Carbon Black-Nafion Modified Glassy Carbon Electrode by Means of Adsorptive Stripping Voltammetry

Adsorptive Stripping Voltammetric method for Nimesulide (NIM) determination was developed. As a working electrode, glassy carbon electrode (GCE) modified with carbon black and Nafion (CB-Nafion GCE) was used. All measurements were carried out in 0.1 M acetate buffer (pH 4.6). Conducted experiments allowed to optimize differential pulse voltammetry (DPV) instrumental parameters: sampling and waiting time t(s) = t(w) = 10 ms, step potential E-s = 4 mV, and pulse amplitude Delta E = 50 mV. The best results were obtained for preconcentration potential and time equal to 400 mV and 20 s, respectively. Limit of detection was calculated and was equal to 0.14 mu M for 20-s preconcentration time and 0.06 mu M for 40-s preconcentration time. In order to prove the applicability of the developed method, concentration of nimesulide in pharmaceutical products was determined. Calculated recoveries were in the range 94-99%, which indicates that the method might be assumed as accurate. Coefficient of variation was equal to 5.0% (n = 7, NIM concentration 1 mu M) Obtained results of NIM determination were in good agreement with the content declared by producers.