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目的建立液相色谱-质谱法测定乳及乳制品中氯霉素类抗生素的残留量。方法液态奶、酸奶、奶粉样本经乙酸乙酯提取,经Waters Sep-pak C_(18)固相萃取小柱净化,至Agilent C_(18)(150 mm×2.1 mm,5μm)色谱柱分离,以乙腈:水(50:50,V:V)为流动相进行等度洗脱。质谱法采用电喷雾离子源负离子模式和多反应监测模式测定,以内标法定量。结果氯霉素、甲砜霉素、氟苯尼考3种待测物质在0.1~20 ng/m L范围内线性关系良好,线性相关系数都在0.9995以上;氯霉素的检出限为0.011~0.021μg/kg,甲砜霉素的检出限为0.042~0.100μg/kg,氟苯尼考的检出限为0.010~0.018μg/kg;氯霉素在0.05、0.5和1μg/kg 3水平上的加标回收率为83.1%~95.6%,甲砜霉素在0.1、1和2μg/kg 3水平上的的加标回收率为80.2%~102.1%,氟苯尼考在0.05、0.5和1μg/kg 3水平上的的加标回收率为81.3%~103.5%;氯霉素的相对标准偏差为4.4%~6.4%,甲砜霉素的相对标准偏差为4.1%~7.1%,氟苯尼考的相对标准偏差为3.7%~6.6%。结论本方法准确灵敏,适用于乳及乳制品中氯霉素类抗生素残留量的测定。
Objective To establish a liquid chromatography-mass spectrometry method for the determination of residual chloramphenicol residues in milk and dairy products. Methods The samples of liquid milk, yogurt and milk powder were extracted with ethyl acetate and purified by a Waters Sep-Pak C 18 solid phase extraction cartridge. The samples were separated on an Agilent C 18 (150 mm × 2.1 mm, 5 μm) Acetonitrile: water (50:50, V: V) as the mobile phase for isocratic elution. Mass spectrometry using electrospray ionization mode negative ion mode and multiple reaction monitoring mode determination, internal standard method. Results The calibration curves of chloramphenicol, thiamphenicol and florfenicol were linear in the range of 0.1 ~ 20 ng / m L with the linear correlation coefficients above 0.9995. The detection limit of chloramphenicol was 0.011 ~ 0.021μg / kg, detection limit of thiamphenicol was 0.042 ~ 0.100μg / kg, florfenicol detection limit was 0.010 ~ 0.018μg / kg; chloramphenicol at 0.05,0.5 and 1μg / kg3 The spiked recoveries were between 83.1% and 95.6% at the levels of 80, 102 and 102.1%, respectively. The recoveries of thiamphenicol at the concentrations of 0.1, 1 and 2 μg / kg 3 were between 80.2% and 102.1% The relative standard deviations of chloramphenicol were 4.4% -6.4%, the relative standard deviations of thiamphenicol were 4.1% -7.1%, and those of fluoride The relative standard deviation of penicillin was 3.7% -6.6%. Conclusion The method is accurate and sensitive and suitable for the determination of chloramphenicol residues in milk and dairy products.