Using Carbon Paste Electrode Modified with Graphene and Nanodiamond for the Determination of Nimesulide in Biologic and Environmental Samples

The present work reports the development and application of a new carbon paste electrode modified with graphene and nanodiamond for the determination of nimesulide in biological and environmental samples. The morphology and electrochemical properties of the carbon nanostructures were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The application of the proposed electrochemical sensor led to a significant improvement in the analytical signal and nimesulide oxidation was found to occur at a potential of +0.97 V (vs. Ag/AgCl (3.0 mol L-1 KCl)). The determination of nimesulide was performed based on the application of differential pulse voltammetry, and the results obtained showed a linear concentration range of 0.50-9.0 mu mol L-1 (r=0.999) with limit of detection of 15 nmol L-1. The proposed analytical method was successfully applied for the determination of nimesulide in spiked river water, serum and synthetic urine samples, where recoveries close to 100 % were obtained.