Differential pulse voltammetric determination of nimesulide in pharmaceutical formulation and human serum at glassy carbon electrode modified by cysteic acid/CNTs based on electrochemical oxidation of l-cysteine

Carbon nanotubes (CNTs) and cysteic acid based on electrochemical oxidation of l-cysteine (CySH) to form a novel composite thin film material at a glassy carbon electrode (GCE) for electroanalytical determination of nimesulide. The determination of nimesulide at the composite modified electrode with strong accumulation of nimesulide was studied by differential pulse voltammetry (DPV). The peak current obtained at +1.251 V (versus SCE) from DPV was linearly dependent on the nimesulide concentration in the range of 1.0 × 10−7–1.0 × 10−5 M in 0.05 M H2SO4 solution with a correlation coefficient of 0.997. The detection limit (S/N = 3) was found to be 5.0 × 10−8 M. The low-cost modified electrode showed good sensitivity, selectivity, stability and had been applied to the determination of nimesulide in pharmaceutical formulation and human serum samples with satisfactory results.