Quantification of dimethoate and chlorpyrifos residues in green leafy vegetables by laser-induced breakdown spectroscopy

Abstract

The presence of pesticide residues in food represents a significant threat to consumers, mainly due to their toxicity to humans. Evidence has even been found that determines the relationship between many diseases and deaths from ingestion, contact, or mishandling. The need to introduce controls on pesticide residues has become an issue of central concern to society, given the increasing knowledge about the potential dangers associated with the use of pesticides. So the objective of the present study was to evaluate and analyze the feasibility of using the laser-induced breakdown spectroscopy technique as a potential tool for the quantification of dimethoate and chlorpyrifos in green leafy vegetables. For this purpose, reference samples with powdered chard were made using the aforementioned pesticides, with increasing concentrations in a range of 0–80 mg kg−1 and 0–250 mg kg−1, respectively. By applying calibration curves, it was possible to quantify pesticide residues by measuring S (416.26 nm), P (460.21 nm), and Cl (837.59 nm) emission lines, with limits of detection of 1.7 mg kg−1, 0.8 mg kg−1, and 6.9 mg kg−1 respectively. Clear evidence of the applicability of this technique as a potential tool for the study of pesticides in food matrices was established. It was achieved by minimum sample preparation, ensuring a rapid analysis, low application costs, and without toxic waste production. In this way, its use as a preliminary evaluation technique or complementary to the analytical methods traditionally already used is evidenced.