A dual-recognition molecularly imprinted electrochemiluminescence sensor based on g-C3N4 nanosheets sensitized by electrodeposited rGO-COOH for sensitive and selective detection of tyramine

Abstract In this study, a novel dual-recognition molecularly imprinted electrochemiluminescence sensor (MIECLS) was prepared for the determination of trace tyramine (Tyr) in foods for the first time. Graphitic-phase carbon nitride (g-C3N4) nanosheets (CNNS) based on reduced carboxylated graphene oxide (rGO-COOH) were introduced to an electrochemiluminescence (ECL) system. rGO-COOH not only steadily promotes the electron transport between the electrode surface and CNNS, but also has an important effect on amplifying the ECL intensity by acting as a carrier for immobilizing CNNS. Molecularly imprinted polymers (MIP) based on o-phenylenediamine were electropolymerized on the electrode surface to form specific imprinted cavities. The quenching effect of Tyr and the addition of MIP endowed the sensor with excellent features of a high sensitivity, selectivity and stability. The proposed ECL intensity linearly declined with the increasing concentration of Tyr in a wide detection range (1 × 10−8−1 × 10−3 mol L−1) and with a low limit of detection (LOD = 1.79 nmol L−1). This MIECLS was also used to determine the Tyr content in rice vinegar, liquor and soy sauce samples, and the results correlated well with those obtained using HPLC, indicating that the developed sensor holds a broad application prospect for food safety detection.