Abstract
This study demonstrates a facile ultrasonication-assisted synthesis of gold nanoparticles (AuNPs) decorated ultrathin graphitic carbon nitride nanosheets (g-C3N4) composite as an efficient electrocatalyst material. The as-prepared g-C3N4/AuNPs composite material's structural morphology was characterized using an X-ray diffractometer, field-emission scanning electron microscopy, and transmission electron microscopy. The prepared nanomaterial was applied to fabricate g-C3N4/AuNPs composite modified screen-printed carbon electrode (SPE) sensor for the sensitive electrochemical detection of caffeic acid (CA) in various food samples. The electrocatalytic properties and interfacial electron movement behavior of the g-C3N4/AuNPs/SPE was examined using electrochemical techniques, including cyclic voltammetry, chronoamperometry, differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy. Under the optimized experimental conditions, g-C3N4/AuNPs/SPE exhibited rapid response and sensitive detection of CA in both amperometric and voltammetric techniques. Excellent linear ranges and detection limits were achieved between the CA's concentration ranging from 0.5 to 155 nM for DPV with the detection limit (LOD) of 0.1 nM and 2.5-1025 nM CA for amperometric technique with LOD of 0.5 nM. The g-C3N4/AuNPs/SPE sensor was successfully applied to quantify the amount of CA in various food samples, and the obtained results were promising over conventional and recently reported methods. Thus, the developed sensor can be applied in routine food quality control and food analysis laboratories for quick and sensitive quantification of CA in foods.