液相色谱-四极杆/离子阱质谱快速测定蜂蜜中痕量硝基咪唑类药物及其代谢物残留

采用液相色谱-四极杆/离子阱串联质谱(LC-QTRAP)建立了蜂蜜中痕量硝基咪唑类药物(甲硝哒唑、咯硝哒唑、二甲硝咪唑、异丙硝唑)及其羟基代谢物(2-羟甲基-1-甲基-5-硝基咪唑、羟基甲硝唑和羟基异丙硝唑)残留的快速测定方法。样品经磷酸盐缓冲液(0.5 mol/L,pH 8.8)/乙酸乙酯提取,高速冷冻离心净化;C18柱色谱分离,流动相为0.1%甲酸水溶液-甲醇,梯度洗脱;质谱采集使用预设定多反应监测(sMRM)-信息依赖性采集(IDA)-增强子离子扫描(EPI)模式;目标分析物使用同位素内标定量,在线EPI谱库辅助定性。7种目标分析物在0.125～50.0μg/L范围内线性关系良好(r>0.999);定量下限(LLD)均达到0.1μg/kg;1LLD、2LLD和4LLD 3个加标水平的回收率为94%～108%;相对标准偏差(RSD)均不大于11.4%。

Rapid Detection of Trace Amounts of Nitroimidazoles and Their Metabolites in Honey Using Liquid Chromatography Coupled with Quadrupole/Linear Ion Trap Mass Spectrometry

A procedure for the fast trace analysis of nitroimidazoles(including metronidazole,ronidazole,dimetridazole and ipronidazole) and their hydroxyl-metabolites(2-hydroxymethyl-1-methyl-5-nitroimidazole,hydroxymetronidazole,hydroxyipronidazole) was developed by liquid chromatography coupled with quadrupole/linear ion trap mass spectrometry.Honey samples were extracted with phosphate buffer(0.5 mol/L,pH 8.8)followed by liquid-liquid partition with ethyl acetate,and cleaned up by high speed freezing centrifugation.The separation of analytes was made on a C18 column using a mobile phase of 0.1% formic acid-methanol by gradient elution.A scheduled multiple reaction monitoring(sMRM) in positive mode as survey scan and an enhanced product ion(EPI) scan as dependent scan in an information-dependent acquisition(IDA) experiment was employed in mass spectrometry acquisition.Stable isotope-labeled analogues were used as the internal standards for quantitation.Confirmative analysis was performed through EPI spectra matching based on on-line lab-built library.Seven analytes showed good linearities in the range of 0.125-50.0 μg/L,with lower limits of detection(LLD) of 0.1 μg/kg for all analytes.At three fortification levels(1LLD,2LLD and 4LLD),the spiked recoveries ranged from 94% to 108% with RSDs no more than 11.4% under within-laboratory reproducibility conditions.The method was simple,rapid,sensitive and accurate,and could meet the requirements for routine analysis and residue surveillance control.