高效液相色谱-串联质谱法分析蔬菜中残留的麦草畏

采用高效液相色谱-串联质谱仪(HPLC-MS/MS)建立了蔬菜中麦草畏的残留分析方法,其中蔬菜基质包括白菜、黄瓜、番茄、豇豆、萝卜、芹菜和葱。样品经 V (乙腈) : V (甲酸) : V (水)=49.5 :0.2 :0.3的混合溶剂提取,并用氯化钠盐析,旋转蒸发浓缩后直接用HPLC-MS/MS测定。采用C18色谱柱,以5 mmol/L的甲酸铵-甲醇为流动相,梯度法洗脱,以电喷雾负离子化模式在多反应监测模式下测定。结果表明,麦草畏在0.005~0.5 mg/L范围内线性关系良好,相关系数( r )为0.999 7。对空白蔬菜样品进行的3个水平(0.01、0.05、0.1mg/kg)的添加回收实验结果表明,麦草畏的平均回收率和相对标准偏差( RSD )分别为80%~120%和0.58%~18.23%,方法检出限为2.0 μg/kg。该方法快速、灵敏,适用于蔬菜中麦草畏的残留分析。

Determination of dicamba residue in vegetables using high performance liquid chromatography-tandem mass spectrometry

An analytical method using high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS) was developed for analysis of dicamba residue in Chinese cabbage,cucumber,tomato,cowpea,white radish,celery and shallot.The sample was extracted with V(acetonitrile) ∶V(formic acid)∶V(water)=49.5∶0.2∶0.3 and salted-out by sodium chloride.After that,the sample was concentrated by rotary evaporator.Seperation was performed on a C18 column with gradient elution by mobile phase of methanol and 5 mmol/L ammonium formate,and finally detected with negative-ion electrospray ionization-mass spectrometry(ESI-MS) under multiple reaction monitoring(MRM) mode.The results showed that the linearity of method for dicamba was in the concentration range of 0.005 to 0.5 mg/L with the correlation coefficients of 0.999 7.The mean spiked recoveries of dicamba at 3 spiked levels(0.01,0.05,0.1 mg/kg) ranged from 80% to 120% with relative standard deviations(RSD,n=3) of 0.58%-18%.The limit of detection was 2.0 μg/kg for dicamba.The method is rapid,sensitive and suitable for determination of dicamba in vegetables.