A MOF nanozyme-mediated acetylcholinesterase-free colorimetric strategy for direct detection of organophosphorus pesticides†

Abstract

Although some simple and rapid colorimetric methods have been developed to detect organophosphorus pesticides (OPs), the difficult extraction and easy denaturation of acetylcholinesterase (AChE) are still drawbacks needing to be overcome. Here, we propose a MOF nanozyme-mediated AChE-free colorimetric strategy for the direct detection of OPs. In the presence of OPs (pirimiphos-methyl as a model), the intense blue of oxidized 3,3′,5,5′-tetramethylbenzidine (TMB) becomes light due to the quenching effect of OPs towards hydroxyl radicals (˙OH) that are generated by the decomposition of H₂O₂ catalyzed by the Cu₄Co₆ ZIF nanozyme with excellent peroxidase (POD)-like activity. The developed colorimetric sensor exhibits assay performance and offers a universal and promising analysis strategy for detecting OPs in practical samples.