Determination of 9 Phenoxy Acid Herbicides in Soil by Solid Phase Extraction and LC/MS/MS / 分析化学

ABSTRACT

A method for the determination of 9 phenoxy acid herbicides in soil by solid phase extraction and LC/MS/MS with matrix correction was developed. The sample was treated by ultrasonic extraction twice with 1. 5% formic acid in acetonitrile. The extract was cleaned up with NH2 solid phase extraction column. A C18 column with formic acid in pure water/methanol mixture as the mobile phase was used under gradient elution. Mass spectral acquisition was done in negative ion mode by multiple reactions monitoring ( MRM ) . Two transitions per compound were used to provide qualitative and quantitative analysis. There were good linear relationships in the range of 2-250 μg/L for 9 phenoxy acid herbicides. The correlation coefficients were in the range of 0 . 9927-0 . 9972 . The method detection limits were in the range of 1 . 66-3 . 82 μg/kg . The average recoveries at three spiked levels ( 10 , 40 , 200 μg/kg ) ranged from 85 . 3% to 110 . 0% with the relative standard deviations (RSD) of 3. 2%-12%.