An electrochemical adsorption-catalysis sensor based on 2D MXene/g-C3N4 doped with Au-COOH for selective detection of GMP in meat

[Display omitted] •An adsorption-catalytic sensor based on 2D MXene/g-C3N4 was developed for GMP detection.•MXene/g-C3N4 is prepared by the electrostatic self-assembly method.•The sensor showed excellent stability with a wide linear range and low detection limit.•The sensor has reasonable practicability in chicken, fish and other practical samples. Guanosine 5′-monophosphate (GMP) is an ubiquitous compound in food and contributes significantly to food flavour due to its prominent umami properties. In this study, the development of MXene/g-C3N4/Au-COOH was synthesised by electrostatic self-assembly. The strong adsorption-catalysis ability of nanocomposites was utilised to attach the GMP to the surface of electrode. The surface morphology, functional groups and chemical bonds were analysed via several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FT-IR), and x-ray photoelectron spectroscopy (XPS). Under the optimised conditions, the GMP concentration detected by the sensor had a linear relationship in the range of 0.1–480 μM (S/N = 3) with a low detection limit of 0.0292 μM. Meanwhile, the MXene/g-C3N4/Au-COOH/GCE has good selectivity, reproducibility and stability. The applicability of the sensor in meat had been successfully verified by four actual samples (chicken broth, fish broth, pork and beef). This study presented a possible strategy to the field of evaluation of meat flavour.