Carboxyl-functionalized graphene oxide-modified electrode for the electrochemical determination of nonsteroidal anti-inflammatory drug diclofenac

A simple and sensitive electrochemical method was proposed for the quantitative determination of nonsteroidal anti-inflammatory drug diclofenac (DCF). For the first time, carboxyl-functionalized graphene oxide (GO-COOH)-modified glassy carbon electrode (GCE) was employed for the determination of DCF by cyclic voltammetry (CV) and linear sweep voltammetric (LSV) techniques. The proposed modified electrode showed strong electrocatalytic activity toward DCF with higher anodic peak enhancement than that of the unmodified electrode. The practicality of the proposed electrode for the detection of DCF in human urine and blood serum samples was successfully demonstrated using LSV techniques. The obtained results were satisfactory. The detection limit and sensitivity of the proposed method were of 0.09 mu M and 0.532 mu A mu M-1 cm(-2), respectively (by LSV). Applicability of the proposed method was verified with commercially available pharmaceutical tablets, and the obtained results were in good agreement with the claimed label amounts of the tablets. In addition, this method could be used for the accurate detection of DCF in clinical and pharmaceutical industries in the future.