高效液相色谱-串联质谱法测定食品中对氯苯氧乙酸的残留量

HPLC-MS/MS Determination of Residual Amount of 4-Chlorophenoxyaceticacid in Foodstuffs

提出了高效液相色谱-串联质谱法测定食品中对氯苯氧乙酸残留量的方法。食品样品经乙酸乙酯提取,过Waters Oasis MAX固相萃取小柱净化。用1.0mL流动相溶解残渣,经ZORBOX SB-C18(50mm×2.1mm,3.5μm)色谱柱分离,用乙腈-0.1%甲酸溶液(45+55)洗脱,采用电喷雾负离子模式多反应监测。对氯苯氧乙酸的质量浓度在500μg.L-1以内与峰面积呈线性关系,检出限(3S/N)为1μg.kg-1。取空白样品在3个标准加入水平下进行了回收和精密度试验,回收率在70.5%～99.8%之间,测定值的相对标准偏差(n=10)在4.6%～10.6%之间。

HPLC-MS/MS was applied to the determination of residual amount of 4-chlorophenoxyacetic acid in foodstuffs. The sample was extracted with ethyl acetate and purified by passing through Waters Oasis MAX solid phase extraction column. The eluate was dissolved with 1 mL of mobile phase and used for HPLC-MS/MS determination, in which ZORBAX SB-C18 column （50 mm × 2. 1 mm, 3. 5 μm） was used as chromatographic column, and a mixture of acetonitrile and 0. 1% methane acid （in the ratio of 45 to 55 by vol. ） was used as mobile phase; negative electrospray ionization as well as multiple reaction monitoring mode was used in the detection. Linear relationship between values of peak area and mass concentration of 4-chlorophenoxyaceticacid was obtained in the range within 500μg · L^-1 , with detection limit （3S/N） of 1μg · kg ^-1. Tests for recovery and precision were made by standard addition method at 3 different concentration levels, values of recovery found were in the range of 70. 50%-99. 80%, and values of RSD＇s （n=10） were in the range of 4. 6%-10. 60%.