Low-potential-triggered luminol-water electrochemiluminescence system integrated with molecularly imprinted polymer for sensitive and selective detection of ochratoxin A.

The luminol-HO electrochemiluminescence (ECL) system has received increasing attention in recent years owing to its ability to overcome the intrinsic drawbacks of conventional co-reactants, specifically the self-decomposition of hydrogen peroxide and low solubility of dissolved oxygen. However, this system still suffers from a high triggering potential, which leads to excessive oxygen (O) bubble accumulation at the electrode surface and unstable ECL signals. Herein, we proposed a new ECL enhancement strategy for the luminol-HO system using multiwalled carbon nanotube (MWCNTs)-functionalized bimetallic cobalt-zinc zeolitic imidazolate framework (CoZn-ZIF) as a co-reactant accelerator. Benefiting from the synergistic interaction, the MWCNTs-modified CoZn-ZIF (CoZn-ZIF@MWCNTs) demonstrated superior oxygen evolution reaction activity at a low potential (0.6 V vs. Ag/AgCl), leading to stable and high-intensity ECL signals through efficient catalytic conversion of HO molecules into hydroxyl radicals (·OH) and superoxide radicals (O). By integrating molecular imprinting technology, a novel ECL sensor was developed for the detection of ochratoxin A, achieving a limit of detection of 0.023 nM (S/N = 3) and wide linear range (0.1-10,000 nM). In real sample analysis, the sensor showed satisfactory recoveries of 99.30 %-110.30 %, demonstrating high accuracy. This work not only establishes a new pathway for enhancing luminol ECL performance but also provides innovative insights for advancing ECL-based sensing technologies in food safety and environmental monitoring.