牛奶中粘菌素和杆菌肽残留的固相萃取超高效液相色谱-串联质谱法测定

建立了牛奶中粘菌素和杆菌肽药物残留的固相萃取-超高效液相色谱-串联质谱测定方法,样品用4%三氯乙酸乙腈溶液提取,经乙醚除脂,HLB固相萃取柱净化,相色谱-串联质谱法分析,外标法定量。结果表明：粘菌素和杆菌肽在20~2 000μg/L浓度范围内呈现良好线性,R2均大于0.998;方法检出限为5μg/kg,定量限为10μg/kg;粘菌素和杆菌肽分别在10~100μg/kg和10~1 000μg/kg浓度添加范围内的平均回收率为84%~110%,批内、批间RSD均小于20%。该方法具有简便快捷、灵敏度高、定性准确等优点,能够满足牛奶中其残留检测有关法规的要求。

Determination of Colistin and Bacitracin Residues in Milk by SPE- UPLC-MS/MS

A ultral performance liquid chromatography- tandem mass spectrometry （UPLC -MS/MS） method was established for the simultaneous determination of colistin and bacitracin residues in milk. The samples were extracted by 4% TCA acetonitril, cleaned up with HLB solid phase extraction （SPE） column. The separation and identify of colistin and bacitracin was performed on UPLC -MS/MS. The method was quantified by external standard method. The calibration curves were linear between the peak areas and the concentrations of 20-2 0130 μg/L with correlation coefficients （R2 ） more than 0. 998. The limit of detection of colistin and bacitracin were all 5 μg/kg, and the limit of quantitation were 10μg/kg. The average recoveries from spiked milk at concentrations of 10 -50 μg/kg and 10 -500 μg/kg ranged from 81% to 116% and the relative standard deviations of intra - and inter -batch were both less than 20%.