Multichannel colorimetric sensor array enabled by microwave-rapidly synthesized Cu/Fe single-atom nanozymes for broad-spectrum pesticide screening

Cu/Fe-N-C SAzymes with dual enzyme activities are rapidly synthesized via microwave. • A four-channel sensor array enables pesticide-specific fingerprint-like responses. • The array discriminates three types of pesticides (5–500 ng/mL) and their mixtures. • LDA and LOOCV confirm robust broad-spectrum screening capability toward pesticides. • High-throughput screening of multi-pesticide residues in fruits is validated. Background The widespread and excessive use of pesticides poses significant risks to both human health and ecological integrity. Inspired by the mammalian olfactory cross-response mechanisms, colorimetric sensor arrays provide a rapid, cost-effective and visual platform for multi-residue pesticide monitoring. Results Herein, we report a four-channel response array constructed from Cu-N-C and Fe-N-C single-atom nanozymes rapidly synthesized via microwave assistance. These nanozymes exhibit intrinsic laccase-like (LAC) and peroxidase-like (POD) dual enzymatic activities, which are differentially modulated by distinct pesticide classes to generate characteristic fingerprint-like responses. Integrating with linear discriminant analysis (LDA) for dimensionality reduction and visualization, this array successfully discriminates three major pesticide categories―sulfonylureas, organophosphates, and carbamates, comprising nine typical pesticides within the discrimination concentration range of 5–500 ng/mL, and further distinguishes pesticide mixtures of varying compositional ratios. Significance Leave-one-out cross-validation (LOOCV) confirms the robust broad-spectrum classification capability of the system. The practical utility of this array is demonstrated through high-throughput screening of multi-pesticide residues in fruit samples. The synergistic integration of microwave-accelerated nanozyme synthesis and multichannel colorimetric sensing establishes a versatile and reliable paradigm for universal pesticide detection in complex matrices. Two single-atom nanozymes, Cu-N-C and Fe-N-C, exhibiting both laccase-and peroxidase-like activities, are rapidly prepared by microwave-assisted synthesis. A four-channel colorimetric array is then established, in which the nanozyme activities are differentially modulated by distinct pesticide categories (sulfonylureas, organophosphates, and carbamates), producing characteristic fingerprint responses. Linear discriminant analysis (LDA) enables precise discrimination of nine pesticides and their mixtures over a concentration range of 5–500 ng/mL, with robust classification confirmed by leave-one-out cross-validation (LOOCV). This platform represents a reliable and efficient strategy for high-throughput screening of multi-pesticide residues in fruits. Download: Download high-res image (303KB) Download: Download full-size image