超高效液相色谱-质谱法测定豆芽中多菌灵、2,4-二氯苯氧乙酸、恩诺沙星残留

建立豆芽中多菌灵、2,4-二氯苯氧乙酸（2,4-dichlorophenoxyacetic acid，2,4-D）、恩诺沙星残留检测的超高效液相色谱-质谱的分析方法。样品经酸化乙腈提取，浓缩后经WAX小柱净化，采用Waters C18色谱柱分离，以甲醇和0.1%甲酸溶液为流动相进行梯度洗脱，采用电喷雾-正负离子多反应监测模式，外标法定量。在5～150 μg/L的质量浓度范围内，各种添加剂相关系数均大于0.999 0，该方法的检出限在0.5 μg/kg之间，定量限在1.5 μg/kg之间。添加5.0、10.0 μg/kg和25.0 μg/kg三个不同水平时，多菌灵、2,4-D、恩诺沙星的回收率在80.4%～97.8%之间，日内和日间相对标准偏差在1.25%～5.47%之间。该方法简单、灵敏度高、分析时间短，适用于多菌灵、2,4-D、恩诺沙星的测定。

Determination of Carbendazim, 2,4-D and Enrofloxacin Residues in Bean Sprouts by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was established for determining carbendazim, 2,4-D, enrofloxacin residues in bean sprouts by ultra
performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS). Samples were extracted with acidified
acetonitrile, and cleaned up on a WAX cartridge. The target analytes were separated on a Waters C18 column with gradient
elution using a mobile phase made up of methanol and 0.1% formic acid. Detection was carried out using positive/
negative electrospray ionization and multiple-reaction monitoring (MRM), and the external standard method was used for
quantification. In the linear range of 5–150 μg/L, the correlation coefficients were all larger than 0.999 0 for carbendazim,
2,4-D and enrofloxacin. The limits of detection (LODs) were 0.5 μg/kg and the limits of quantitation (LOQs) were 1.5 μg/kg.
The recovery rates at three spiked levels of 5.0, 10.0 and 25.0 μg/kg were in the range of 80.4%–97.8%. The relative
standard deviation (RSD) of intra-day and inter-day assays was 1.25%–5.47%. The method proved to be simple, sensitive,
rapid and suitable for the determination of carbendazim, 2,4-D and enrofloxacin residues in bean sprouts.