Iron/manganese-zeolitic imidazolate framework (Fe/Mn-ZIF) nanozyme combined with acetylcholinesterase for colorimetric rapid detection of organophosphorus pesticides.

Organophosphorus pesticides (OPs) are extensively utilized in agricultural production, but they pose significant threats to environment and organisms. This study aims to develop a novel method for the rapid and efficient detection of OPs. Initially, an iron/manganese zeolitic imidazolate framework (Fe/Mn-ZIF) with excellent oxidase-like activity was synthesised. The catalytic performance was evaluated, and the main factors influencing catalytic activity were investigated. Subsequently, a combined acetylcholinesterase assay was employed to detect three OPs. The specificity and recyclability of Fe/Mn-ZIF were also studied. The proposed colorimetric strategy demonstrated strong linear relationships: 0.1-2 mg/L for trichlorfon, 0.2-14 mg/L for glyphosate, and 0.4-10 mg/L for glufosinate, with the low detection limits of 0.024, 0.080, and 0.121 mg/L (3 S/N) respectively. Good recoveries were observed in real sample detection. This work lays a foundation for enhancing the catalytic performance of Fe/Mn-ZIF, which holds promise for biosensing applications.