Zinc oxide modified carbon paste electrode sensor for the voltammetric detection of L-tryptophan in presence of uric acid and ascorbic acid

Abstract

The mechanochemical method was used for the synthesis of Zinc oxide nanoparticles (ZnONps) and was characterized by energy-dispersive spectroscopy (EDAX) scanning electron microscopy (SEM) and X-ray diffraction (XRD). Using a zinc oxide modified carbon paste electrode (ZnOMCPE) the oxidative response of L-tryptophan (LTP) was analyzed by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. CV was used to scrutinize the parameters of pH, concentration and scan rate of LTP. In this work, compared to bare carbon paste electrode (BCPE), the modified electrode shows enhanced peak current. CV exhibits a good linearity in the concentration range 10–40 μM (LTP). The limit of detection (LOD) and limit of quantification (LOQ) values of LTP were observe to be 0.57 and 1.72 μM respectively. DPV was used to study the analytical individualization and interference study of L-tryptophan (LTP), Uric acid (UA) and Ascorbic acid (AA). The above outcome shows that the polished surface of the modified electrode gives excellent sensitivity and selectivity in its voltammetric response and good LOD for LTP.