Electrocatalytic oxidation of glucose onto carbon paste electrode modified with nickel hydroxide decorated NaA nanozeolite

In this study, a NaA nanozeolite was synthesized and characterized by an X-ray diffraction, scanning electron microscopy, nitrogen sorption and infrared spectroscopy. Crystal particle sizes of synthesized NaA nanozeolite were observed about 75 nm by SEM. Carbon paste electrode (CPE) was modified by NaA nanozeolite and Ni2+ ions. The electrocatalytic performance of the Ni-NaA/CPE toward glucose oxidation was evaluated by cyclic voltammetry, chronoamperometry, amperometry and differential pulsed voltammetry (DPV) techniques. The values of electron transfer coefficient, electrode surface coverage and charge-transfer rate constant for Ni(III)/Ni(II) redox couple were obtained to be 0.63, 3.98 x 10(-8) mol cm(-2) and 0.126 s(-1), respectively. Also, the electron transfer coefficient, the diffusion coefficient and the mean value of catalytic rate constant for glucose and redox sites of electrode were found to be 0.86, 2.41 x 10(-7) cm(2) s(-1) and 3.65 x 10(4) cm(3) mol(-1) s(-1), respectively. The sensor was exhibited an acceptable linear range of 0.04-6.54 mM with detection limits of 1.98 x 10(-3) mM (S/N = 3) by amperometric technique. Also, a linear range of 0.5 to 50.0 mu M with detection limits of 0.02 mu M was obtained by DPV method. The modified electrode (Ni-NaA/CPE) was successfully applied for the quantitative determination of glucose in blood serum samples by amperometric method and mean of recovery percentage was obtained to be 96.4%. (C) 2016 Elsevier B.V. All tights reserved.