title: A method for determination of imazapic and imazethapyr residues in soil using an ultrasonic assisted extraction and LC-MS/MS.
abstract: At least 52 % of the planted rice area in Rio Grande do Sul, a major rice producing state in Brazil, employs Clearfield(®) production system, corresponding to 580,000 ha of cultivated area. To grow rice with Clearfield(®) technology, producers combine imazethapyr and imazapic herbicides. However, these herbicides leave residual activity in soil; consequently, the repeated application of imazethapyr and imazapic on Brazilian Clearfield(®) rice fields has increased these herbicides persistence in treated soils. In this study, a method has been developed for removal and quantification of imazethapyr and imazapic residues in soil through ultrasonic assisted extraction using methanol-phosphoric acid aqueous solution (pH 2.0). The detected response was linear for both herbicides within the range of 0.25-5 ng mL(-1) with correlations coefficients >0.99. The quantification limit was limit of quantification 0.2 µg Kg(-1) for both pesticides. The good recovery rate from all pesticides, which ranges between 70 % and 120 %, demonstrates the method's validity.
authors.affiliation: EMBRAPA Meio Ambiente, P.O Box 69, Jaguariúna, SP, 13820-000, Brazil, marcia.assalin@embrapa.br.
authors.forename: Márcia Regina
authors.initials: MR
authors.lastname: Assalin
authors.forename: Sonia C N
authors.initials: SC
authors.lastname: Queiroz
authors.forename: Vera L
authors.initials: VL
authors.lastname: Ferracini
authors.forename: Taciana
authors.initials: T
authors.lastname: Oliveira
authors.forename: Eder
authors.initials: E
authors.lastname: Vilhena
authors.forename: Maria Laura T
authors.initials: ML
authors.lastname: Mattos
mesh_terms: D001938:Brazil; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000032:analysis*; D007093:Imidazoles / Q000032:analysis*; D059625:Liquid-Liquid Extraction / Q000379:methods*; D013058:Mass Spectrometry; D009539:Nicotinic Acids / Q000032:analysis*; D012275:Oryza; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014465:Ultrasonics
chemical_list: D006540:Herbicides; D007093:Imidazoles; D009539:Nicotinic Acids; D012987:Soil; D012989:Soil Pollutants; C093630:imazethapyr; C481028:imazapic