Benign approach for the synthesis of ZnO hexagonal plates for electrochemical sensing of l-tryptophan

Abstract

L-tryptophan is amino acid which can significantly affects metabolic activities in humans and herbivore animals. l-tryptophan also known as precursor for melatonin, and serotonin and its level should be controlled in the human body. Thus, it is required to develop the cost-effective, simple processed, sensitive and selective l-tryptophan. In this paper, we reported benign approach for the synthesis of ZnO hexagonal plates. Various advanced physiochemical techniques such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopic (XPS) were adopted to characterize the synthesized of ZnO hexagonal plates. Glassy carbon electrode (GCE) was modified with ZnO hexagonal plates using drop cast method. This modified GCE (ZnO/GCE) was applied as tryptophan sensor. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques were adopted for the detection of tryptophan (TRP). The limit of detection (LOD) of 1.49 μM and 0.94 μM were obtained using CV and LSV, respectively. The fabricated electrode (ZnO/GCE) also exhibited excellent stability, reproducibility, repeatability, and selectivity towards the determination of l-tryptophan.