A simple, ultrasensitive sensor for gallic acid and uric acid based on gold microclusters/sulfonate functionalized graphene modified glassy carbon electrode

Taking advantage of the unique plane structure of the functionalized graphene, Au microclusters (AuCMs) were successfully electrodeposited on the surface of sulfonate functionalized graphene (SF-GR) and AuCMs/SF-GR/GCE was constructed and thoroughly characterized. The prepared electrode was applied to the independent determination of GA in black tea and Cortex moutan as well as the simultaneous determination of GA and UA in urine samples. The AuCMs/SF-GR/GCE exhibited a variety of advantages such as uniqueness, high anti-interference ability, low detection limit and wide linearity range, and significantly enhanced the anodic peak currents of GA and UA. Meanwhile, the spiked results determined by AuCMs/SF-GR/GCE were compared to the results detected by HPLC. With high sensitivity and selectivity, good reproducibility, low solvent consumption and without time-consuming sample pretreatment, the electrochemical method is easier, faster and reliable. Therefore, the novel sensors constructed was applicable to simultaneous determine GA and UA in human urine samples and respective detect GA in black tea, Cortex moutan samples. •A simple, ultrasensitive and reliable AuCMs/SF-GR/GCE was fabricated and characterized.•The AuCMs/SF-GR/GCE was successfully applied to the independent determination of GA as well as the simultaneous determination of GA and UA.•Common substances existing in the samples did not interfered in the electrode performance.•The modified electrode exhibited considerable sensitivity, stability and reproducibility.•The LODs of GA and UA achieve a satisfactory level compared with other electrodes. A facile and ultrasensitive sensor based on gold microclusters (AuMCs) electrodeposited on sulfonate functionalized graphene (SF-GR) was fabricated, and applied for the simultaneous determination of gallic acid (GA) and uric acid (UA). Taking advantage of the unique plane structure of the functionalized graphene (GR), the AuMCs were successfully electrodeposited on functionalized GR immobilized on the surface of a GCE. The results of scanning electron microscope (SEM) and energy spectrum analysis illustrated that AuMCs were deposited on the functionalized GR film. In comparison with the bare GCE, the pristine AuMCs and the pristine SF-GR modified electrode, AuMCs/SF-GR/GCE exhibited excellent electrochemical oxidation toward GA and UA. In addition, the two compounds were separated completely in 0.10M citric acid-sodium citrate buffer (pH 4.0) by differential