超高效液相色谱-串联质谱法测定乳制品中残留青霉素

目的建立1种超高效液相色谱-串联质谱联用法测定乳制品中8种青霉素类抗生素残留的确证方法。方法乳制品样品用水提取后,经乙腈沉淀蛋白,正己烷液液萃取除去脂肪,用氮气吹至近干,用乙腈＋水（10＋90）复溶后,经0.22μm微孔滤膜过滤,经Endeavorsil C18柱分离,选用乙腈（含0.1%甲酸）-水（含0.1%甲酸）为流动相,13 min内梯度洗脱分离8种青霉素;在优化的质谱条件下,采用ESI源、正离子模式、多反应监测方式、外标法定量。结果在浓度范围1.0～100.0μg/kg,8种青霉素类药物在各种乳制品基质中均有良好的线性关系,相关系数为0.999 2～0.999 8,方法最低检测限为0.03～0.15μg/kg,方法回收率为91.0%～102.3%,相对标准偏差为1.02%～6.13%。用本研究建立的方法检测78份奶粉、液体牛奶、鲜奶、奶饮料样品,其中3份样品检出青霉素G,含量为0.2～1.6μg/kg。结论该方法测定牛奶中8种青霉素药物的残留量简便、快速、准确,可以满足对牛奶中青霉素残留的检测要求。

Ultra-high performance liquid chromatography tandem mass spectrometry for analysis of penicillin residues in milk products

Objective To establish a method of ultra-high performance liquid chromatography-tandem mass spectrometry（ UHPLC-MS / MS） for determination of residues of eight penicillins in milk products. Methods Samples of milk products were extracted by water in super-sonic instrument. Proteins in the extract were precipitated by acetonitrile and degreased by n-hexane with liquid-liquid extraction,then the purified solution was concentrated by nitrogen,dissolved with acetonitrile-water（ 10 ＋ 90,v / v） and cleaned by 0. 22 μm millipore filter. The filtrate was separated on a Endeavorsil C18 column by gradient elution in 13 minutes with acetronitrile-water（ containing 0. 1% formic acid） as mobile phase. Eight penicillins in milk products were detected by UHPLC-MS / MS,identified by electrospray ionization in positive mode using multiple reaction monitoring,and quantified with external standards. Results The calibration curves of residues of eight penicillins showed good linearity in the range of 1. 0- 100. 0 μg / kg with correlation coefficient in the range of 0. 999 2- 0. 999 8. The detection limit of the method was from 0. 03 μg / kg to 0. 15 μg / kg. The recoveries at three spiking levels ranged from 91. 0% to102. 3%,and relative standard deviations in the range of 1. 02%- 6. 13% were obtained. A total of 78 samples of milk powder,liquid milk,fresh milk,and milk beverage were analyzed. Three samples were proved to contain penicillin G in the range of 0. 2- 1. 6 μg / kg. Conclusion The method was applied to determine residues of eight penicilins in milk products by UPLC-MS / MS and proved to be simple,rapid,and accurate,and meet the requirements of monitoring of penicillin in milk products.