title: Evaluation of a modified QuEChERS extraction of multiple classes of pesticides from a rice paddy soil by LC-APCI-MS/MS.
abstract: A new method for the determination of clomazone, fipronil, tebuconazole, propiconazole, and azoxystrobin in samples of rice paddy soil is presented. The extraction of the pesticides from soil samples was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Some extraction conditions such as salt addition, sample acidification, use of buffer, and cleanup step were evaluated. The optimized method dealt with a single extraction of the compounds under study with acidified acetonitrile, followed by the addition of MgSO(4) and NaCl prior to the final determination by liquid chromatography-atmospheric chemical pressure ionization-tandem mass spectrometry. Validation studies were carried out in soil samples. Recoveries of the spiked samples ranged between 70.3 and 120% with relative standard deviation lower than 18.2%. The limits of quantification were between 10 and 50 μg kg(-1). The method was applied to the analysis of real samples of soils where rice is cultivated.
authors: Post-graduation Program in Technological and Environmental Chemistry, Escola de Química e Alimentos, Laboratório de Análise de Compostos Orgânicos e Metais, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul State 96201-900, Brazil.
authors: Sergiane S
authors: SS
authors: Caldas
authors: Cátia M
authors: CM
authors: Bolzan
authors: Maristela B
authors: MB
authors: Cerqueira
authors: Débora
authors: D
authors: Tomasini
authors: Eliana B
authors: EB
authors: Furlong
authors: Carlos
authors: C
authors: Fagundes
authors: Ednei G
authors: EG
authors: Primel
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D012275:Oryza / Q000254:growth & development; D010573:Pesticide Residues / Q000032:analysis* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis* / Q000302:isolation & purification*; D053719:Tandem Mass Spectrometry
chemical_list: D010573:Pesticide Residues; D012989:Soil Pollutants