Ultrasensitive molecularly imprinted electrochemiluminescence sensor based on highly-conductive rGO-COOH synergically amplify TCPP luminophor signal in aqueous phase system for “switches-controlled” detection of tryptamine

Abstract

An efficient and innovative molecularly imprinted electrochemiluminescence sensor (MIECLS) based on the reduced carboxylated graphene oxide (rGO-COOH) amplifying aqueous phase meso-tetra(4-carboxyphenyl)porphyrin (TCPP) signal was constructed for “switches-controlled” detection of tryptamine (Tryp). The conductive rGO-COOH uninterruptedly accelerated the high-energy electrons injection into the aqueous co-reaction system of green metal-free TCPP, and more excited state molecules (TCPP*) were generated to obtain excellent ECL signal. Benefiting from the large specific surface area provided by rGO-COOH, molecularly imprinted polymer (MIP) with specific recognition cavities can be firmly electropolymerized on the surface of rGO-COOH/glassy carbon electrode (GCE), which regulated electrons transfer rate to realize “switches-controlled” detection by elution and recombination of Tryp. Under optimal conditions, the MIECLS exhibited a favorable linear relationship with Tryp in the concentration range of 1 × 10−9–1 × 10−4 mol L−1 and the limit of detection (LOD) was 0.25 × 10−9 mol L−1. The MIECLS was used for Tryp detection in actual samples with the satisfactory results (recovery rate, 83.19–91.32%) and consistent with that of HPLC. The dual application of TCPP and MIP/rGO-COOH/GCE can create nicely synergistic effect for the Tryp detection, making a novel avenue to the rapid analysis of other food hazards.