▎ 摘　　要

An effective electrochemical sensor based on "poly L- methionine/Electrochemically Reduced Graphene Oxide Composite Film Modified Glassy Carbon Electrode (poly(L-Met)/ERGO/GCE))" has been developed for the individual and simultaneous determination of 5-hydroxyindole acetic acid (5-HIAA) and tyrosine (Tyr). In clinical point of view, simultaneous determination of these analytes is very important and a sensor for the same is not reported yet. This sensor offers sensitive, reproducible and selective determination of 5-HIAA and Tyr. Experimental parameters for the effective determination of the analytes were optimized. Under optimized conditions, quantification of 5-HIAA is possible within the range 1.0 x 10(-5) M to 8.0 x 10(-7) M and for Tyr in two ranges, 1.0 x 10(-5) M to 5.0 x 10(-6) M and 7.0 x 10(-5) M to 2.0 x 10(-5) M. The limit of detection and limit of quantification obtained for 5-HIAA using poly(L-Met)/ERGO/GCE are 5.0 x 10(-7) M and 8.0 x 10(-7) M respectively, and for Tyr, 1.0 x 10(-6) M and 5.0 x 10(-6) M respectively. The sensor was successfully applied for the determination of both 5-HIAA and Tyr in artificial urine and blood serum samples. (C) 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.