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

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.