Electrochemical Sensing of Tryptophan and Tyrosine in Chronic Kidney Disease Patients Using Magnetic Core/Ag Nanoparticles Shell Nanocomposite Modified Electrode

Abstract This paper reports the production of a novel magnetic nanocomposite based on core-shell Fe3O4@Ag nanoparticles. Fe3O4@Ag nanoparticles were used to fabricate a modified carbon paste electrode (Fe3O4@Ag/CPE). Fe3O4@Ag/CPE was investigated for the simultaneous determination of tryptophan (Trp) and tyrosine (Tyr) in an aqueous media (0.1 M phosphate buffer solution, pH 6.5) using square wave voltammetry. The synthesized nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction spectroscopy. The proposed electrode for Trp and Tyr exhibits linearity in the range of 0.5–100 µM with detection limits of 0.05 and 0.04 µM for Trp and Tyr, respectively. The novel proposed voltammetric method was successfully applied to the simultaneous determination of serum Trp and Tyr levels of chronic kidney disease patients with results similar to those obtained using a high performance liquid chromatography method at a 95% confidence level.