Validation and application of a QuEChERS based method for estimation of half-life of imidazolinone herbicides in soils by LC-ESI-MS/MS.
A modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method was validated and applied for the estimation of half-lives of two imidazolinone group herbicides, imazethapyr and imazapic, in the Dystric Plinthosol (FX) and Ferralsol (LVA) agricultural soils using liquid chromatography tandem mass spectrometry. The solutions were prepared in a matrix extract to avoid matrix effects. The analytical method showed satisfactory specificity, selectivity, linearity (R2 > 0.99), recoveries (range 85.0-117.0%), with RSD between 6.7% and 16.6%, and precision (range 94.7-108.5%), with RSD between 6.0% and 11.9%. The limit of detections for imazethapyr and imazapic in the soils were 2.2 µg kg-1 and 2.0 µg kg-1, and the limit of quantifications were 6.6 µg kg-1 and 6.1 µg kg-1. The half-lives of imazethapyr (35.7 and 97.9 days) and imazapic (40.4 and 64.4 days), in the FX and LVA soils, respectively, indicate that they are medium-persistence herbicides with possibility of leaching into groundwater. In addition, high concentrations of imazethapyr and imazapic were found in the soil samples after the time of application, meaning that there is a potential for prolonged soil residual activity due to carryover.
['da Costa Marinho|Maria Inês|MI|', 'Costa|Anna Isabel Guido|AIG|', 'Vieira|Nívea Moreira|NM|', 'Paiva|Maria Carolina Gomes|MCG|', 'de Freitas|Francisco Cláudio Lopes|FCL|', 'da Silva|Antonio Alberto|AA|']
D002851:Chromatography, High Pressure Liquid D002853:Chromatography, Liquid D006207:Half-Life D006540:Herbicides D007093:Imidazoles D009539:Nicotinic Acids D012680:Sensitivity and Specificity D012987:Soil D012989:Soil Pollutants D053719:Tandem Mass Spectrometry
QuEChERS Half-life Imidazolinone Leaching Persistence