Nickel-Cobalt Salen Organometallic Complexes Encapsulated in Mesoporous NaA Nanozeolite for Electrocatalytic Quantification of Ascorbic Acid and Paracetamol

Abstract

Goal of current study was fabrication of novel voltammetric nanosensor for the synchronize quantification of ascorbic acid (AA) and paracetamol (PAR) by nickel-cobalt salen complexes encapsulated in the supercages of NaA nanozeolite modified carbon paste electrode (NiCoSalenA/CPE). For this purpose, NiCoSalenA nanocomposite was firstly prepared and characterized by various methods. Also, cyclic voltammetry (CV), choronoamperometry (CHA) and differential pulse voltammetry (DPV) were utilized to evaluate performance of the modified electrodes. The effects of pH and modifier amount were considered on the electrochemical oxidation of AA and PAR on the surface of NiCoSalenA/CPE. Results from this method indicated that pH of 3.0 in phosphate buffer solution (0.1 M) and 15 wt% of NiCoSalenA nanocomposite in the modified CPE results in the maximum current density. The oxidation signals of AA and PAR was amplified affectively at NiCoSalenA/CPE versus unmodified CPE. The limit of detection (LOD) and linear dynamic range (LDR) for the simultaneous measurement of them were founds to be 0.82 and 2.73–80.70 for AA and 0.51 µM, 1.71–32.50 and 32.50–137.60 µM for PAR, respectively. The catalytic rate constants (k cat) were attained to be 3.73 × 107 and 1.27 × 107 cm3 mol−1 s−1 for AA and PAR via CHA method, respectively. Also, the amounts of diffusion coefficient (D) were found to be 1.12 × 10−7 and 1.92 × 10−7 cm2 s−1 for AA and PAR, respectively. The average value of electron transfer rate constant between NiCoSalenA/CPE and PAR was obtained to be 0.016 s−1. The NiCoSalen-A/CPE displayed worthy stability, repeatability and extraordinary recovery for simultaneous measurements of AA and PAR. Application of offered sensor was confirmed by quantifying concentrations of AA and PAR in human serum solution as a real sample.