A Sensitive Electrochemical Sensor Based on Graphene/Pt Nanoparticles for Simultaneous Determination of Tyrosine and Tryptophan in the Presence of 5-hydroxytryptophan

摘要

A composite material, namely, graphene/ Pt nanoparticles (GR/PtNPs) was prepared in this work. Thiscomposite material was characterized by transmission electron microscopy (TEM) and Fouriertransform infrared spectroscopy (FTIR). Based on GR/PtNPs modifed glassy carbon electrode (GR/PtNPs/GCE), a sensitive and simple sensor was developed for simultaneous measurement oftryptophan (Trp) and tyrosine (Tyr) in the presence of 5-hydroxytryptophan(5-HTP). Under optimizedmeasurement conditions, the oxidation peak current of Tyr increased linearly within a concentrationrange from 5.0 × 10?7to 2.0 × 10?5 mol/L with a detection limit of 1.25×10-7 mol/L. The linearresponse of Trp was also obtained in the range from 2.0 × 10?7to 1.2 × 10 ?5 mol/L, and the detectionlimit was 8.22×10-8 mol/L. When Tyr and Trp samples were measured, the recovery rate of tyrosinewas 98.4% to 103.5%, and the recovery rate of tryptophan was 98.7% to 102.9%, which indicates thatthe accuracy of GR/PtNPs/GCE was high. Additionally, the GR/ PtNPs/GCE demonstrated suitableselectivity for the determination of tryptophan (Trp) and tyrosine (Tyr), making it practicable for theirmeasurement of Trp and Tyr in pharmaceutical formulations.