A new electrochemical sensor was developed for determination of diclofenac based on functionalized multiwalled carbon nanotubes (f-MWCNTs) and gold–platinum bimetallic nanoparticles (Au–PtNPs) modified gold electrode. The Au–PtNPs were deposited electrochemically on the surface of the f-MWCNTs modified electrode. The surface morphologies of the modified electrodes were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical properties of the constructed sensor. Under the optimized experimental conditions, the calibration curve was linear in the concentration range of 0.5 μM to 1000 μM of diclofenac and the detection limit was found to be 0.3 μM. The developed electrode also showed a high selectivity for diclofenac in the presence of the interfering species. The reproducibility, repeatability and stability of the electrode were satisfactory. The proposed electrochemical sensor was successfully employed for determination of diclofenac in real samples such as tablet and human urine samples.

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