A novel electrochemical sensor of tryptophan based on silver nanoparticles/metal–organic framework composite modified glassy carbon electrode

Abstract

For the first time, a familiar metal–organic framework MIL-101(Fe) and silver nanoparticles composite (AgNPs/MIL-101) acted as a novel electrode modified material for the detection of tryptophan (Trp). The AgNPs/MIL-101 modified glassy carbon electrode (AgNPs/MIL-101/GCE) produces an increase in the oxidation current of Trp compared with the bare electrode. Additionally, the electrochemical behaviours of Trp on AgNPs/MIL-101/GCE were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimum experimental conditions, the oxidation peak currents are proportional to the concentrations of tryptophan over the ranges of 1 μM to 50 μM and 50 μM to 150 μM, respectively. The detection limit is 0.14 μM (S/N = 3). Moreover, the presented method was successfully applied to the determination of Trp in urine samples with good recovery.