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

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.

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.

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.