Microextraction technique associated with gas chromatography-mass spectrometry for determining pesticide residues in urine

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Pesticides, food contaminants, and agricultural wastes, 2022, Vol.57 (3), p.165-175
• Main Authors: Silva, Thaís L. R., de Queiroz, Maria Eliana L. R., de Oliveira, André Fernando, Rodrigues, Alessandra A. Z., Neves, Antônio Augusto, Vieira, Patrícia A. F., de Queiroz, José Humberto, Barbosa, Verônica O. de P.
• Format: Article
• Language: English
• Subjects: Acetonitrile; Alachlor; Aldrin; biological sample; Chlorpyrifos; Chlorpyrifos - analysis; Chromatography; clean-up; Contamination; Design optimization; Dieldrin; Endrin; Factorial design; Freezing; Gas chromatography; Gas Chromatography-Mass Spectrometry - methods; Herbicides; Humans; Insecticides; Lindane; Linearity; Liquid Phase Microextraction; Low temperature; Mass spectrometry; Mass spectroscopy; method validation; Permethrin; Pesticide residues; Pesticide Residues - analysis; Pesticides; Pesticides - analysis; sample preparation; Scientific imaging; Selectivity; Spectroscopy; Urine; µLLE/LTP-GC-MS
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601234.2022.2038505

Urine is one of the biological matrices most used for detecting human contamination, as it is representative and easily obtained via noninvasive sampling. This study proposes a fast, accurate, and ecological method based on liquid-liquid microextraction with low-temperature partition (μLLE/LTP). It was validated to determine nine pesticides (lindane, alachlor, aldrin, chlorpyrifos, dieldrin, endrin, DDT, bifenthrin, and permethrin) in human urine, in association with gas chromatography coupled with mass spectrometry (GC-MS). The technique was optimized through a factorial design. The best conditions for the simultaneous extraction of the analytes comprised the addition of 600 µL of water and 600 µL of acetonitrile (extracting solvent) to a 500-µL urine sample, followed by vortexing for 60 s. By freezing the samples for 4 h, it was possible to extract the pesticides and perform the extract clean-up simultaneously. The parameters selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy were used to appraise the performance of the method. Good values of selectivity and linearity (R 2 > 0.990), LOQ (0.39-1.02 μg L −1 ), accuracy (88-119% recovery), and precision (%CV ≤ 15%) were obtained. The μLLE/LTP-GC-MS method was applied to authentic urine samples collected from volunteers in Southeast Brazil.