Electrochemical detection of tryptophan in fish and pharmaceutical supplement at glassy carbon electrode modified with Fe doped ZnO nanoparticle

Abstract

The co‐precipitation approach was employed in this study to create Fe doped ZnO (Fe‐ZnO) nanoparticles (NPs). To characterize the synthesized NPs, Ultra violet‐Visible (UV‐Vis) spectroscopy, X‐ray diffraction (XRD), fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), and Brunauer‐Emmett‐Teller (BET) were used. Here, a novel electrochemical approach for the detection of tryptophan (Trp) using a glassy carbon electrode modified with Fe‐ZnO NPs (Fe‐ZnO/GCE) is demonstrated. The research findings revealed that Fe‐ZnO/GCE enhanced the electron transfer rate of Trp oxidation. The sensitivity of Trp detection using Fe‐ZnO/GCE in phosphate buffer solution (PBS) at pH 64.0 was significantly improved compared to bare GCE due to the electrocatalytic activity of Fe‐ZnO NPs. Fe‐ZnO/GCE exhibited a linear response with Trp concentrations ranging from 0.1 to 150 μM with the limit of detection (LOD) is 0.089 μM (3σ/m) and limit of quantification (LOQ) about 0.3 μM (10σ/m) using linear sweep voltammetry (LSV). The Fe‐ZnO/GCE sensor was also effectively used to detect Trp in African catfish and multivitamin tablets. Trp analysis in real samples exhibited good recovery values of 89.60 to 99.15 %, demonstrating the accuracy and practicality of the method.