Molecularly imprinted electrochemiluminescence sensor based on a Co/Zn-MOF@POMs composite for sensitive and selective detection of fumonisin B1.

Abstract

Fumonisin B1 (FB1), a highly toxic secondary metabolite produced by Fusarium fungi, poses a significant threat to global food safety; therefore, sensitive, selective, and reliable analytical methods are urgently needed. In this work, we report a novel molecularly imprinted electrochemiluminescence (ECL) sensor for the quantitative determination of FB1. A Co/Zn bimetallic metal-organic framework@polyoxometalate (Co/Zn-MOF@POMs) nanocomposite was synthesized via a one-pot strategy and used to modify a glassy carbon electrode. The incorporated polyoxometalates (POMs) markedly improved the interfacial electron-transfer kinetics of the Co/Zn-MOF scaffold, resulting in substantial amplification of the ECL signal generated by ZnAgInS quantum dots (QDs). Subsequently, a molecularly imprinted polymer (MIP) layer was electropolymerized on the modified electrode using o-phenylenediamine as the functional monomer and 1,2,3-propanetricarboxylic acid as a structural dummy template designed to mimic key topological and functional features of FB1. Upon FB1 rebinding, the exposed amine groups on the captured FB1 molecules underwent a condensation reaction with carboxyl-functionalized ZnAgInS QDs, enabling site-specific immobilization of the luminophores close to the recognition cavities. Under optimized conditions, the sensor exhibited a linear ECL response to FB1 over a concentration range of 6.0 × 10^-14 to 1.0 × 10^-10 mol L^-1 (R² = 0.9987), with a detection limit of 3.3 × 10^-15 mol L^-1 (S/N = 3). This approach offers a robust and reproducible platform for trace-level FB1 monitoring in real-world food and agricultural samples.