Estabelecimento de método multirresíduo de agrotóxicos em água para avaliação da potabilidade

Abstract

Water is an essential resource for life, playing a fundamental role in controlling organism temperature, dissolving essential substances, and facilitating physiological and biochemical processes such as nutrient transportation and metabolic reactions. Driven by the need to meet the growing global demand for food, pesticides are widely used in modern agriculture. However, pesticide use carries significant risks to human health and the environment. These chemicals can contaminate not only soils but also the atmosphere, surface waters, groundwater, and even food. This contamination negatively affects terrestrial and aquatic organisms, increasing the risk of human and occupational poisoning. As a safety measure for the population, governments establish parameters for controlling and monitoring water quality, determining maximum permissible values for substances that may pose contamination risks. Thus, the present study aimed to establish a method for determining pesticide residues in water using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) after the sample preparation by solid-phase extraction (SPE). Sample preparation involved the percolation of 100 mL of sample adjusted to pH 6.0, through the Oasis® HLB 60 mg/3 mL cartridge. The cartridge conditioning was performed with 3 mL methanol followed by 3 mL of ultrapure water, and elution with 2 mL of methanol:acetonitrile 1:1 containing 1% (v/v) acetic acid. The extracts were diluted 1:1 with mobile phase and analyzed by UHPLC-MS/MS using electrospray ionization (ESI). For the chromatographic separation an Acquity BEH C18 column (50 x 2.1 mm, 1.7 μm) was used with a mobile phase composed of (A) H2O:methanol 98:2 (v/v) and (B) methanol:H2O 98:2 (v/v), both containing 0.1% (v/v) formic acid and ammonium formate at 5 mmol L-1. The accuracy and precision results were satisfactory for 51 compounds, with a limit of quantification for most compounds of 0.02 μg L-1. The method was applied to 31 water samples collected in the state of Rio Grande do Sul. Based on the obtained results, the proposed method proved suitable for the multi- residue determination of pesticides in water for human consumption and can be applied in routine analyses.