Dynamic visual monitoring of triazole pesticide residues and penetration behavior in fruits and vegetables by surface-enhanced Raman spectroscopy combined with chemometrics

Triazole pesticides are widely used to control pathogenic fungi in agricultural production, but the irrational use of these pesticides will have many negative effects on human health and ecological environment. In this study, we constructed a relatively complete visual monitoring system for triazole pesticides based on surface-enhanced Raman spectroscopy (SERS). Silver nanoparticles (Ag@ICNPs) modified with iodide and calcium ions showed stronger SERS enhanced ability and better reproducibility, and the characteristic peaks of eight different triazole pesticides were captured simultaneously. Principal component analysis (PCA) and support vector machine (SVM) were used to identify these pesticides. The developed method has strong quantitative analysis ability, excellent detection sensitivity and wide detection range, and has been successfully applied to the determination of pesticide residues in fruits and vegetables. In addition, dynamic SERS imaging technology combined with multivariate curve resolution-alternating least squares (MCR-ALS) to visually monitor the penetration behavior of triazole pesticides could remove the influence of interfering substances, thus obtaining an accurate distribution map of pesticides, which promoted the quantification of pesticide penetration process. The diffusion ability of different systemic pesticides into fruits and vegetables was revealed. Electrochemical (EC) assisted SERS of triazole pesticides showed that potential-induced molecular reorientation of pesticide molecules on the electrode surface was induced by the polarization of active substrate, which significantly improved the SERS signal of pesticides. Overall, this systematic pesticide monitoring study not only provides an effective innovative scheme for controlling the detection of hazardous substances in agricultural products, but also brings significant prospects for food safety guarantee.