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

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

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。

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- 3.82μg/kg . The average recoveries at three spiked levels （10, 40, 200μg/kg） ranged from 85.3% to 110.0% with the relative standard deviations （RSD） of 3.2% -12%.