气相色谱-串联质谱法测定水果、蔬菜中乙烯利的残留量

建立了水果、蔬菜中乙烯利化合物残留量的气相色谱-串联质谱(GC-MS/MS)检测方法,样品经甲醇超声提取,盐酸水溶液调节pH,N-(特丁基二甲基硅烷)-N-甲基三氟乙酰胺(MTBSTFA)衍生,采用GC-MS/MS多反应监测模式分析,基质外标法定量。结果表明,在pH为4.0的提取环境下,衍生化试剂添加量为10.0μL、60℃时反应30.0 min的条件下,乙烯利衍生化产物响应最好。乙烯利在0.01~1.00 mg/kg的范围内线性关系良好,决定系数(R^2)为0.9993,方法检出限(S/N≥3)为0.200μg/kg,定量限(S/N≥10)为0.600μg/kg。在低中高三个添加水平下,乙烯利的平均回收率范围为81.3%~105.0%,相对标准偏差小于5.4%。该方法操作简单快速、灵敏度和选择性高,适用于水果、蔬菜中乙烯利的日常检测。

Determination of Ethephon Residues in Fruits and Vegetables by Gas Chromatography-tandem Mass Spectrometry

A gas chromatography-tandem mass spectrometry(GC-MS/MS)was established for the determination of ethephon residues in fruits and vegetables. Samples of fruits and vegetables were extracted with methanol,and then the pH value was adjusted by hydrochloric acid solution. The purified extract was derived by MTBSTFA,and then quantified by external standard method in multiple reactions monitoring mode(MRM). Results showed that,the ethephon-derived product had the best response under the extraction environment of pH4.0,the derivatization reagent was added in an amount of 10.0 μL,and at 60 ℃ for 30.0 min. The target concentrations and peak areas were linearly correlated in the range of 0.01~1.00 mg/kg,and the correlation coefficient was 0.9993. The limit of detection(LOD)and the limit of quantitation(LOQ)was 0.200 and 0.600 μg/kg. Recovery studies were carried out fewer than three levels of low,medium and high,the mean recoveries were 81.3%~105.0%,with relative standard deviations less than 5.4%. The method is simple,fast,sensitive and selective. It is suitable for routine testing of ethephon in the fruits and vegetables.