Zeolite integrated carbon paste sensors for sensitive and selective differential pulse voltammetric determination of carprofen

Abstract

The present research demonstrates the development and the electroanalytical performance of a novel carprofen (CAR) voltammetric carbon paste electrode (CPEs). Fortification of the electrode matrix with zeolite (ZY) nanostructures with an effective electrocatalytic activity catalyzes the oxidation of the CAR molecule at the ZY/CPEs surface in the universal buffer pH 5 with irreversible anodic oxidation peak at 0.954 V following a diffusion-electrode reaction mechanism. The postulated electrooxidation mechanism of CAR molecule undergoes through oxidation of the enamine N atom (N6) through the transfer of the delocalized lone pair of electrons in addition to the involvement of one proton as estimated from the electrochemical behavior of CAR at different scan rates, pH values and sustained with the molecular orbital calculations. Calibration graphs were linear within the CAR concentration ranged from 16.6 to 323.3 ng mL−1 recording a limit of detection (LOD) value of 5.6 ng mL−1. The cited ZY/CPEs showed enhanced performance, high measurement reproducibility, ease of construction and regeneration of the electrode surface, with a prolonged operational lifetime. Based on the recorded sensitivity and selectivity, ZY/CPEs were utilized for simultaneous quantification of CAR in the presence of various interferents and degradation products. The presented voltammetric analytical technique was tested for monitoring of CAR residues in veterinary and biological samples with acceptable recoveries values compared with the official chromatographic techniques.