Bandgap-Regulated Electrochemiluminescence Enhancement Strategy for Florfenicol Detection Based on ZrCuO₃: A Multimodal Luminophore

The low electrochemiluminescence (ECL) efficiency issue of zirconia (ZrO2) has been a pressing problem since its discovery. In this study, a bandgap-regulated ECL enhancement strategy was developed to improve the ECL efficiency of ZrO2. Specifically, through the calcination of metal-organic frameworks (MOFs), the MOF-derived bimetallic oxide ZrCuO3 was synthesized. Compared to ZrO2, the synthesized ZrCuO3 exhibited a narrower bandgap and higher electron transfer efficiency, leading to enhanced ECL efficiency. Further investigation of the ECL emitter revealed that ZrCuO3 exhibited multimodal ECL emission: annihilation ECL and co-reactant participation ECL (including anodic ECL with tripropylamine as a co-reactant and cathodic ECL with K2S2O8 as a co-reactant). The anodic ECL with the highest efficiency was selected as the main mode for detecting the target in the aptasensor. Annihilation ECL and cathodic ECL served as alternative modes to ensure stability and continuity of the sensing system. Based on the bandgap-regulated strategy of ZrCuO3, a sensing chip with ITO as the working electrode was designed for the sensitive detection of florfenicol (FF). The constructed signal "off-on-off" aptasensor exhibited excellent detection performance for FF in the range of 0.0005-200 ng/mL. The proposed method provided a novel strategy for the analysis of other antibiotics or biomolecules.