Platinum nanozyme catalyzed multichannel colorimetric sensor array for identification and detection of pesticides

Pesticide residues have a great threat to human health and environment. Herein, a simple multichannel colorimetric sensor array was constructed for the identification and detection of pesticides by using Pt nanoparticles (Pt NPs) as nanozyme sensing receptor. Pt NPs can catalyze the direct oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to generate three greatly enhanced adsorption peaks located at 370 nm, 450 nm, and 650 nm, just providing three cross-reactive sensing elements for identification. Distinctive colorimetric responses and fingerprint-like patterns for each pesticide were obtained based on the differential inhibition or enhancement effect of pesticides on the catalytic activity of Pt NPs. Five pesticides, including dursban (DB), dimethoate (DM), 3-ketocarbofuran (3-KC), glyphosate (GLY), and malathion (MA) were successfully discriminated by using principal component analysis and hierarchical cluster analysis. In addition, identification of three pesticides with different concentrations, pesticides mixtures with different mass ratios, unknown pesticide samples, and spiked pesticides on apple were also demonstrated. Finally, a colorimetric assay was further developed for DM detection with linear range from 0.5 to 9 ug/mL. This work presents a simple nanozyme based colorimetric sensor array for the identification and detection of pesticides, which has great application potential in food safety and environmental protection fields.