Sulphur-doped graphene based sensor for rapid and efficient gallic acid detection from food related samples

Abstract

BackgroundNowadays, the food safety issue represents a hot topic. The emerging evidence over the past decade confirms that gallic acid (GA) plays a crucial role, with multiple pharmacological and therapeutic interventions in numerous health complications. MethodsSulphur-doped graphene material (exf-SGR) was obtained from graphite rod electrochemical exfoliation in the presence of inorganic salts mixture such as sodium thiosulfate and ammonium sulphate, Na2S2O3 / (NH4)2SO4 (0.2 M each), at low applied bias (6 V). The complete physico-chemical characterization of the as-prepared material was performed by means of TEM, SEM, STEM-EDS, XRD and XPS analysis. Furthermore, the electrochemical performances of bare glassy carbon (GCE) and modified (exf-SGR/GCE) electrodes for GA assay were evaluated. Significant findingsTEM/SEM images reveal the formation of large dimension graphene sheets having uniformly distributed spherical sulphur crystallites on the surface. XRD demonstrates that the material consists of few-layer S-doped graphenes. From XPS analysis the C/O ratio was determined to be 0.473 while C/S ratio equals 2.741, indicating a high heteroatom doping degree. The exf-SGR/GCE modified electrode shows a superior electrochemical behaviour over a broad GA detection range (0.1–100.0 µM), with a low detection limit (3.03 × 10−8 M). The electrode retains 96.83% of its initial response after 50 consecutive CV measurements indicating an excellent long-term stability and repeatability. The sensor possesses very good anti-interfering capabilities in complex matrix. The developed electrochemical sensor can provide a fast model for GA detection in food related and biological real sample analysis.