提出了通过型固相萃取净化结合超高效液相色谱-串联质谱法(UHPLC-MS/MS)测定果蔬中乙烯利残留量的方法。取5.00 g样品,用20 mL水高速匀浆2 min,离心3 min,上清液用水定容至25 mL。取5 mL上述溶液过GCB-HLB复合固相萃取柱(预先用5 mL甲醇、5 mL水活化),弃去前3 mL流出液,收集后2 mL,过0.22 μm聚四氟乙烯(PTFE)滤膜。滤液中的乙烯利在Dikma Polyamino HILIC色谱柱上进行分离,质谱分析采用多反应监测模式,基质匹配法制作工作曲线,外标法定量。结果表明,在不同基质中,乙烯利的质量浓度在2.5~1 000 μg·L^-1内与对应的峰面积呈线性关系,检出限(3S/N)为2.0 μg·kg^-1。按照标准加入法进行回收试验,回收率为81.6%~95.3%,测定值的相对标准偏差(n=6)为4.5%~9.2%。方法用于56份果蔬样品的分析,结果显示乙烯利的检出率为53.4%,检出量为0.023~1.223 mg·kg^-1。

A method for the determination of residue of ethephon in fruits and vegetables by passing solid phase extraction purification combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was proposed. The sample (5.00 g) was homogenized with 20 mL of water at a high speed for 2 min, and centrifuged for 3 min. The supernatant was made its volume up to 25 mL with water. 5 mL of the above solution was taken through the GCB-HLB composite solid phase extraction column (activated with 5 mL of methanol and 5 mL of water), the first 3 mL of effluent was discarded, and the last 2 mL was collected and passed through 0.22 μm PTFE filter membrane. Ethephon in the filtrate was separated on Dikma Polyamino HILIC column. Multiple reaction monitoring mode was adopted in MS analysis, and external standard method with the working curve made by matrix matched method was used for quantitative analysis. As shown by the results, linear relationships between mass concentration of ethephon in different matrices and the corresponding peak area were found in the range of 2.5-1 000 μg·L^-1, with detection limit (3S/N) of 2.0 μg·kg^-1. Test for recovery was made by the standard addition method, giving results in the range of 81.6%-95.3%, with RSDs (n=6) of the determined values in the range of 4.5%-9.2%. This method was applied to analysis of 56 fruit and vegetable samples, and it was shown that the detection rate of ethephon was 53.4%, and the detection amounts were in the range of 0.023-1.223 mg·kg^-1.