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目的采用同位素内标-超高效液相色谱-串联质谱法测定蜂蜜中氯霉素及甲硝唑的残留量。方法样品经乙酸乙酯提取,MCS复合型固相萃取柱(500 mg/6 ml)净化,采用ZORBAXSB-C18色谱柱(2.1 mm×100 mm,1.8μm)分离,以甲醇和5 mmol/L乙酸铵溶液(含0.05%甲酸)为流动相进行梯度洗脱,采用电喷雾正/负离子多反应监测模式检测,同位素内标法定量。结果氯霉素、甲硝唑的浓度为0.05~5.00 ng/ml时,线性关系良好,相关系数r>0.999。添加0.5、2.0、5.0μg/kg三个不同水平时,氯霉素、甲硝唑的回收率为79.3%~96.7%,相对标准偏差(RSD)为5.5%~14.8%,定量限均为0.15μg/kg,检出限均为0.05μg/kg。结论该方法灵敏度及准确度良好,可应用于日常大批量样品的高灵敏分析。
Objective To determine the residual amount of chloramphenicol and metronidazole in honey by isotope internal standard-ultra performance liquid chromatography-tandem mass spectrometry. Methods The samples were extracted with ethyl acetate and purified on an MCS composite solid phase extraction column (500 mg / 6 ml). The separation was performed on a ZORBAXSB-C18 column (2.1 mm × 100 mm, 1.8 μm) using methanol and 5 mmol / Ammonium solution (containing 0.05% formic acid) as the mobile phase gradient elution by electrospray positive / negative ion multiple reaction monitoring mode detection, isotope internal standard method. Results When the concentrations of chloramphenicol and metronidazole were between 0.05 and 5.00 ng / ml, the linear relationship was good with the correlation coefficient r> 0.999. The recoveries of chloramphenicol and metronidazole were 79.3% ~ 96.7% with relative standard deviations (RSDs) of 5.5% ~ 14.8% at the three different levels of 0.5, 2.0 and 5.0 μg / kg, μg / kg, the detection limits are 0.05μg / kg. Conclusion The method has good sensitivity and accuracy and can be applied to the high sensitive analysis of daily large batch samples.