Determination of Haloxyfop-Methyl, Linuron, and Procymidone Pesticides in Carrot Using SLE-LTP Extraction and GC-MS

Abstract

This study aimed to optimize and validate an analytical method for extraction, detection, and quantification of haloxyfop-methyl, procymidone, and linuron pesticides in carrot samples using solid–liquid extraction methods and low temperature partition (SLE-LTP), accompanied by gas chromatography coupled to mass spectrometry (GC-MS). For SLE-LTP technical optimization, we utilized a complete factorial planning, which had as its variables, agitation time, freezing time, and the correct sample mass/extracting solution volume ratio. The organic extract obtained was analyzed by GC-MS. To test the performance of this procedure, the method was validated and applied to the monitoring of pesticide residues in 20 samples of carrot produced in Alto Paranaíba, Minas Gerais, Brazil. The proposed method showed linearity between 0.5 and 3.5 mg·kg−1 with correlation coefficients greater than 0.99. The quantification limits were 0.48 mg·kg−1 for haloxyfop-methyl, 0.69 mg·kg−1 for linuron, and 0.65 mg·kg−1 for procymidone, values below the maximum residue limit provided by international legislation of 1.0 mg·kg−1 for linuron and procymidone. The use of haloxyfop-methyl is not approved in the cultivation of carrot. The recovery percentages were between 90 and 110 %, with a coefficient of variation of less than 12 %. Ten percent of the carrot samples monitored showed residues of linuron and procymidone in concentrations exceeding those permitted by Brazilian law.