建立了高效液相色谱-串联质谱法同时测定化妆品中四环素、甲硝唑、氧氟沙星、磺胺吡啶等40种抗菌药物的检测方法。样品采用20%乙腈（含0.5%甲酸）作为提取溶剂,LC部分采用0.5%甲酸水溶液为流动相A,0.5%甲酸的乙腈溶液为流动相B,梯度洗脱,进样量为2 μL,流速为0.3 mL/min,柱温为30 ℃,MS部分采用电喷雾离子源、正离子多反应监测模式（MRM）测定,外标法定量。结果表明40种抗菌药物的线性范围为20~100 μg/L,相关系数大于0.997,检出限为0.025~0.25 μg/g,在低中高3种加标质量浓度下,40种抗菌药物的平均回收率为73.8%~109.1%。筛查的84批次样品中有1批次样品检出甲硝唑,1批次样品检出环丙沙星,1批次样品检出甲硝唑和氧氟沙星。该方法具有良好的选择性、灵敏度和准确性,可用于化妆品中40种非法添加抗菌药物的同时测定。
A liquid chromatography-tandem mass spectrometry（LC-MS/MS） method for the simultaneous determination of 40 antibacterial agents including tetracycline, metronidazole, ofloxacin and sulfapyridine in cosmetics was established. The samples were extracted with 20% acetonitrile （containing 0.5% formic acid） as the extraction solvent. The LC part used 0.5% formic acid aqueous solution as the mobile phase A and 0.5% formic acid in acetonitrile solution as the mobile phase B, gradient elution, the injection volume was 2 μL, the flow rate was 0.3 mL/min, and the column temperature was 30 ℃. The MS part was determined by electrospray ion source, positive ion multiple reaction monitoring mode （MRM）, and the external standard method was used for quantitative analysis. The results show that the linear range of 40 antibiotics was within 20-100 μg/L, the correlation coefficient was more than 0.997, and the detection limit was within 0.025-0.25 μg/g. The average recovery rate of 40 antibiotics was 73.8%-109.1% at the low, medium and high spiked mass concentrations. Among the 84 batches of samples screened, 1 batch of samples detected metronidazole, 1 batch of samples detected ciprofloxacin, and 1 batch of samples detected metronidazole and ofloxacin. The method has good selectivity, sensitivity and accuracy, and can be used for the simultaneous determination of 40 illegally added antibacterial agents in cosmetics.
