高效液相色谱-四极杆飞行时间质谱法同时检测豆芽中的3种外源植物激素残留

建立了高效液相色谱-四极杆飞行时间质谱同时测定豆芽中6-苄基腺嘌呤、4-氯苯氧乙酸、赤霉素等3种外源植物激素残留的方法。采用QuEChERS前处理技术，豆芽样品以酸化乙醇-乙腈溶液（1%（v/v，下同）乙酸+50%乙醇+49%乙腈）提取目标化合物，并经乙腈再提取后合并提取液；经硅藻土分散固相净化、正己烷去脂后氮吹至近干；用2.0 mL 50%（v/v）甲醇水溶液定容，过滤膜后上机检测。液相色谱以甲醇-水（含0.1%（v/v）的甲酸）作为流动相梯度洗脱，C₁₈色谱柱分离；质谱采用高分辨质谱、负离子模式，以精确质量数和二级特征离子定性，以准分子离子峰面积定量。结果表明3种目标化合物的定量限为5.0~10.0 μg/kg，线性范围为1~200 μg/L；平均添加回收率为79.1%~96.1%，相对标准偏差为5.7%~10.4%。本方法具有操作简单、快捷、灵敏度高等优点，适用于市场上豆芽质量的快速筛查检测。

Determination of three exogenous plant hormone residues in bean sprout by high performance liquid chromatography-quadrupole-time of flight mass spectrometry

This study was aimed to the establishment of an analytical method for the determination of three exogenous plant hormone residues in bean sprout by high performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF-MS). The target compounds were gibberellins, 6-benzylaminopurine and parachlorophenoxyacetic acid. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used for sample preparation. The analytes were extracted with a solution containing 1% (v/v, if not specified) acetic, 50% ethanol, 49% acetonitrile, and cleaned-up by dispersive solid-phase extraction with diatomite dispersant, then degreased by hexane. The three target compounds were separated on an Eclipse Plus C₁₈ column (100 mm×3.0 mm, 1.8 μm) with mobile phases A (water containing 0.1% formic acid) and B (methanol) by gradient elution within 15 min, and detected under negative electrospray ionization (ESI) mode. The quantitative analysis was carried out by extracting the peak area with accurate mass. The confirmatory analysis of the target compounds was performed with the qualitative fragments. The results showed that the limits of quantification (LOQs, S/N=10) for the three target compounds were from 5.0 μg/kg to 10 μg/kg. The respective mean recoveries were found to be in the range of 79.1%-96.1%, and the RSDs were 5.7%-10.4%. It was applicable to the analysis of the three exogenous plant hormones in bean sprout samples. This method is simple, fast and efficient.