Identification and detection of pesticide in chard samples by laser-induced breakdown spectroscopy using chemometric methods

Highlights: • P, S, C, and Cl were detected in pesticide-contaminated chard samples using LIBS. • PCA and LDA were used for analysis of LIBS data for characterization of pesticides. • Pesticides residues were successfully determined by LIBS and chemometric methods. Pesticide residues in food represent a significant threat to consumers. However, the fast detection of traces directly in samples involves a complex task. In this work, we explore the potential application of the Laser-Induced Breakdown Spectroscopy (LIBS) technique for the rapid measurement of pesticide residues in chard leaves by identifying them from the signal recording of the emission lines of P, S, C and Cl. They are subsequently jointly described through a principal components analysis (PCA) and grouping of the samples according to their pesticide was corroborated by means of a linear discriminant analysis (LDA), with an error rate of less than 9.5%. Moreover, differences can be observed in the classification of groups with a 95% confidence level. There is thus, clear evidence of the applicability of this technique as a potential tool for the study of pesticide residues in food matrices.