超高效液相色谱-串联质谱法测定豆芽中7种药物残留

建立了甲醇超声提取，分散固相萃取净化技术（QuEChERS）净化，超高效液相色谱-串联三重四极杆质谱（UPLC-MS/MS）检测豆芽中7种药物（咪鲜胺、头孢氨苄、诺氟沙星、6-苄氨基嘌呤、赤霉酸、2,4-二氯苯氧乙酸和4-氯苯氧乙酸）残留的方法。样品用含0.1%甲酸的甲醇溶液超声提取，QuEChERS（PSA+C18）净化，在UPLC-MS/MS的电喷雾正、负离子分段扫描和多反应监测（MRM）模式下检测，以保留时间和特征离子对定性，外标法定量。结果表明，7种待测物在0.4~100 μg/L范围内线性关系良好；方法定量限（S/N=10）为2.0~5.0 μg/kg；添加水平为2.0~50 μg/kg时，平均回收率在80.7%~115%之间；相对标准偏差（RSD，n=6）为2.6%~13.5%。本方法具有前处理简单、结果准确、回收率高等特点，可以应用于豆芽中7种药物残留的日常监测。

Determination of Seven Drug Residues in Bean Sprouts by UPLC-MS/MS

A method for determination of seven drug residues (cefalexin, norfloxacin, prochloraz, 6-benzylaminourine, gibberellic acid, 4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid ) in bean sprouts was established by quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation methods， combined with ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The sample was extracted by methanol containing 0.1% formic acid through ultrasonic wave, and was purified by QuEChERS which was composed of PSA and C18, and analyzed using UPLC-MS/MS on a UPLC HSS T3 column with acetonitrile and 0.1% formic acid solution as the mobile phases in gradient elution program．The MS analysis was set in electrospray ionization mode and separated to two segments of positive and negative modes．Seven compounds were identified by retention time and the ratio of the characteristic ions, and quantitatived with external standard method. The result shows that the calibration curves are good linearity in the range of 0.4—100 μg/L with correlation coefficients more than 0.999. The method quantitation limit (MLOQ, S/N=10) of 7 compounds are 2.0—5.0 μg/kg. The average recoveries are between 80.7% and 115% at the spiked levels of 2.0—50 μg/kg, the precision (RSD, n=6) ranges from 2.6% to 13.5%. The method is simple, sensitive, and accurate, which can be applied in daily monitoring of 7 drug residues in bean sprouts.