Fabrication of a new electrocatalytic sensor for determination of diclofenac, morphine and mefenamic acid using synergic effect of NiO-SWCNT and 2, 4-dimethyl-N/-[1- (2, 3-dihydroxy phenyl) methylidene] aniline

Abstract

An electrochemical sensor developed for analysis of diclofenac by modification of carbon paste electrodes using NiO-SWCNTs as conductive mediator and 2, 4-dimethyl-N/-[1-(2, 3-dihydroxy phenyl) methylidene] aniline (DDPM) as electro-catalyst (NiO-SWCNTs/DDPM/CPE). We detected three completely separate signals at the potentials of∼247 mV,∼445 mV and 697 mV for oxidation of diclofenac, morphine and mefenamic acid at the surface of NiO-SWCNTs/DDPM/CPE which are sufficient for analysis of diclofenac in the existence of mefenamic acid and morphine. The electrocatalytic currents of diclofenac, morphine and mefenamic acid are linearly with their concentrations in the ranges of 0.04–1200, 0.9–400, and 1.0–600μM, with detection limits of 0.008, 0.4 and 0.5μM at a surface of NiO-SWCNTs/DDPM/CPE, respectively. The RSD% for seven replicate determinations of 15.0μM of diclofenac, 45.0μM of morphine and 80.0μM mefenamic acid were 2.1, 2.5 and 3.1%, respectively. The NiO-SWCNTs/DDPM/CPE was used for the analysis of diclofenac, morphine and mefenamic acid in real samples.