固相萃取-高效液相色谱-串质谱法测定蜂胶中氯霉素残留

Overcoming Lipophilic Interference in Propolis to Quantify Residual Chloramphenicol by Solid-Phase Extraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry

该文建立固相萃取结合高效液相色谱-串联质谱技术(solid phase extraction-high performance liquid chromatography-tandem mass spectrometry,SPE-HPLC-MS/MS)测定蜂胶中氯霉素残留的检测方法。蜂胶样品经乙腈溶解,氢氧化钙溶液沉淀杂质,Bond Elut Plexa固相萃取柱(6mL,200mg)净化,Kinetex C18色谱柱(50mm×2.1mm,2.6μm)分离,以水-乙腈为流动相梯度洗脱分离,在负模式下,采用多反应监测(multiple reaction monitoring,MRM)模式检测,内标法定量。结果表明,氯霉素在0.1μg/L~500.0μg/L范围内线性关系良好(R2>0.99),检出限为0.4μg/kg,定量限为1.0μg/kg。氯霉素在蜂胶样品中添加水平为1、2、10μg/kg时平均回收率为93.2%~103.4%,日内和日间相对标准偏差分别为0.98%~3.95%和0.93%~5.37%(n=5)。该方法操作简便,耗时短,灵敏度高,稳定性好,适用于蜂胶中氯霉素残留筛查检测及定量分析。

An approach using solid phase extraction-high performance liquid chromatography-mass spectrometry(HPLC-MS/MS)was developed for determination of chloramphenicol(CAP)residue in propolis. The propo lis samples were dissolved in acetonitrile,and then calcium hydroxide [Ca(OH)2] solution was added to break the lipophilic interferences. Solid phase extraction column(Bond Elut Plexa,6 mL,200 mg)was used to remove other impurities from propolis prior to HPLC-MS/MS analysis. The target compound was separated on Kinetex C18 column(50.0 mm×2.1 mm,2.6 μm)with mobile phase of water and acetonitrile.The quantitative detection was performed using an electrospray ionization source in negative ionization mode under multiple reaction monitoring(MRM).An isotopically labeled CAP(CAP-D5)as the internal standard was used to quantify CAP residue in propolis.The standard curve was constructed and exhibited a strong linear relationship(R2>0.99)in the range of 0.1 μg/L-500.0 μg/L. The limit of detection(LOD)for CAP in propolis was 0.4 μg/kg,and the limit of quantification(LOQ)was 1.0 μg/kg. The method was validated by analyzing samples spiked at three levels of 1,2,10 μg/kg. The recoveries ranged from 93.2% to 103.4%,intra-and inter-day precisionrelative standard deviation(RSD)ranged from 0.98% to 3.95% and 0.93% to 5.37%(n =5),respectively. The method was simple,rapid,sensitive and stable,whichis suitable to screen and quantify CAP residue in propolis.