HPLC-MS/MS法测定饲料中甲硝唑和二甲硝咪唑含量

Determination of metronidazole and dimetridazole in feed by high performance liquid chromatography-tandem mass spectrometry

关键词:  液相色谱-串联质谱  饲料  含量分析  甲硝唑  二甲硝咪唑

Key words:  high performance liquid chromatography-tandem mass spectrometry  feed  content analysis  metronidazole  dimetridazole

摘要:

建立了高效液相色谱-串联质谱法（HPLC-MS/MS）快速测定饲料中的甲硝唑和二甲硝咪唑。饲料样品用乙酸乙酯提取后，经PCX固相萃取柱净化处理，过0.22 μm滤膜，以乙腈和含0.1%的甲酸水溶液为流动相，经Eclipse Plus C18色谱柱（3.0 mm×100 mm，1.8 μm）分离，多级反应监测（MRM）正离子模式下扫描分析。结果表明，甲硝唑和二甲硝咪唑在0.2~50 μg/L范围呈良好线性，线性相关系数均大于0.997，检出限均为0.2 μg/kg，定量下限均为0.5 μg/kg。样品在定量下限1倍、2倍、10倍3个加标水平下的平均回收率为95.3%~103.2%，相对标准偏差（RSD）为4.67%~8.46%。该方法灵敏、简便、准确，可用于饲料中甲硝唑和二甲硝咪唑的检测分析。

Abstract:

A method for the determination of metronidazole and dimetridazole in feed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is presented. The sample were purified with Solid phase extraction column of PCX after extraction by ethyl acetate. After filtered with a 0.22 μm membrane, the sample was separated on a Eclipse Plus C18 column（3.0 mm × 100 mm, 1.8 μm）using gradient elution with mobile phases of acetonitrile and aqueous solution containing 0.1% formic acid, and detected on positive electrospray ionization with a multiple reaction monitoring (MRM) as survey scan. The results showed that the calibration curves were linear in the range of 0.2-50 μg/L for metronidazole and dimetridazole with correlation coefficient (r) more than 0.997. The LODs for metronidazole and dimetridazole was 0.2 μg/kg and the LOQs was 0.5 μg/kg. The average recoveries (n=6) in feed samples at three spiked levels（1 tismes, 2 times, 10 times） ranged from 95.3% to 103.2% with relative standard deviations (RSDs) of 4.67 – 8.46%. The method was sensitive, convenient and accurate, and could satisfy the demand of detection and analysis of metronidazole and dimetridazole in feed.