A Colorimetric Sensor Array Combining Chemometrics for Detection and Recognition of Organophosphorus Pesticides Based on Core–Shell ZIF‐67/FeCoO

ABSTRACT Organophosphorus pesticides (OPs) are easy to enter the human body and cause great harm to the human respiratory system and nervous system, with the accumulation of the food chain. Herein, a layer of iron‐cobalt oxide is loaded on the surface of the original ZIF‐67, and the core–shell ZIF‐67/FeCoO nanozyme is successfully synthesized. It is found that the nanozyme at a Co:Fe molar ratio of 2:1 has excellent oxidase‐like enzyme‐like activity. The steady‐state kinetic results show that the material has strong substrate affinity ( K _m = 0.339 m m ) and fast reaction rate ( V _max = 2.3 × 10 ⁻⁸ M s ⁻¹ ). •OH is involved in the catalytic process of 3,3',5,5'‐tetramethylbenzidine (TMB) by ZIF‐67/FeCoO. Combined with the inhibitory effect of OPs on acetylcholinesterase (AChE), a simple colorimetric sensor is developed to detect parathion‐methyl (PM) with a detection limit as low as 0.0143 ng/mL, which is successfully used for quantitative detection of pesticide residues in actual samples (lake water, pear, cabbage). Satisfactory recovery and low relative standard deviation are obtained. In addition, principal component analysis and hierarchical clustering analysis are used to classify and identify a variety of OPs and their multivariate mixtures, showing the significant recognition ability of the colorimetric array sensor.