Gln-GQD-Enabled FeCoNiCuAu0.5-High Entropy Alloy Nanoparticles for Ultrasensitive and Non-Invasive Electrochemical Uric Acid Detection

Abstract

The limited sensitivity restricts the practical application of present electrochemical sensors for detection of uric acid in human sweat. The paper reported one approach for construction of FeCoNiCuAu0.5 high-entropy alloy nanoparticles (FeCoNiCuAu0.5-HEA) by introducing glutamine-functionalized graphene quantum dot (Gln-GQD). Fe3+, Co2+, Ni2+ and Cu2+ are combined with Gln-GQD to form stable complex, which sebsequently coordinated with Au3+. Followed by two-stage thermal annealing in N2 atmosphere. The resulting FeCoNiCuAu0.5-HEA shows one spherical nanostructure with small particle size of 47.5±0.63 nm, FCC and BCC phase, and uniform distribution of all metal elements. The HEA nanoparticles are well dispered on the three-dimensional graphene framework formed by graphene sheets intertwining each other. The integration of five metal element mixture and Gln-GQD introduction achieves to excellent electron/ion conductivity, good affinity with ploar electrolyte, and significantly enhanced catalytic activity. The catalytic activity is more than 2.7 times of gold nanoparticles. The FeCoNiCuAu0.5-HEA-based sensor offers an ultrasensitive electrochemical response towards uric acid. The differential pulse voltammetric peak current will linearly increase with the increase of uric acid concentration in the range of 0.01-1 M uric acid with a detection limit of 4.3×10-9 M (S/N=3). The as-proposed analytical method provides the advantage of high sensitivity, selectivity and repeatability for detection of uric acid in human sweat.