固相萃取液相色谱-串联质谱法测定土壤中9种苯氧羧酸类除草剂残留量

摘要

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%.%建立了基质校正液相色谱-串联质谱( HPLC-MS/MS)同时测定土壤中9种苯氧羧酸类除草剂残留量的分析方法。样品用含1.5%甲酸的乙腈溶液超声提取两次，提取液经氨基柱净化后，使用C18色谱柱，以含甲酸的水溶液和甲醇为流动相，在梯度条件下进行分离。在多级反应离子监测( MRM)负离子模式下进行质谱数据采集，采用两对离子进行定性和定量分析。9种苯氧羧酸类除草剂在2~250μg/L浓度范围内呈线性关系，相关系数为0.9929~0.9972；检出限在1.7~3.8μg/kg之间。土壤中9种苯氧羧酸类除草剂的3个浓度水平加标的平均回收率为85.3%~110.0%，相对标准偏差在3.2%~12.0%之间。