液相色谱-质谱联用法测定牛奶中4种四环素类药物残留量

Measurement of the four tetracycline residues in the milk by high-performance liquid chromatography mass spectrometry

目的建立牛奶样品中四环素、土霉素、金霉素、美他环素药物残留量的测定方法 ,进一步探讨四环素类药物的电喷雾质谱规律。方法生物样品经固相萃取后 ,采用HypersilBDS柱分离 ,以乙腈 水 甲酸 (体积比 37 5∶6 2 5∶1 2 )作为流动相 ,采用电喷雾离子源 ,以正离子检测方式进行一级、二级质谱分析。结果牛奶中四环素、土霉素及美他环素的检测限可达 0 0 5 μg/mL,金霉素的检测限可达 0 1 μg/mL。四环素、土霉素及美他环素的浓度在 0 1～ 5 0 μg/mL内 ,金霉素浓度在0 2～ 1 0 0 μg/mL内均呈线性。结论该方法专属性强 ,灵敏度高 。

Objective Developing a method for determination of residues of tetracyclines, oxytetracycline, chlortetracycline and metacycline in the milk. Method The tetracyclines were extracted from the milk using solid phase extraction and were determined by liquid chromatography electrospray mass spectrometry with the mobile phase of acetonitrile water formic acid (37 5∶62 5∶1 2, V/V) . Result The detection limits were 0 05 μg/mL for tetracyclines, oxytetracycline and metacycline, and 0 1 μg/mL for chlortetracycline, respectively. The calibration curves are linear from 0 1 to 5 0 μg/mL for tetracyclines, oxytetracycline and metacycline, and 0 2 to 10 0 μg/mL for chlortetracycline. Conclusion This method was specific, sensitive, and suitable for determination of the residual tetracyclines in the milk or other biological samples. The pathways of mass fragmentation of tetracyclines were also interpreted.