分散固相萃取净化/液相色谱-串联质谱法同时测定蜂王浆中双甲脒、单甲脒及其代谢物

建立了分散固相萃取净化/液相色谱-串联质谱(dSPE/LC-MS/MS)测定蜂王浆中双甲脒、单甲脒(DMPF)及其代谢物2,4-二甲基苯基甲酰胺(DMF)和2,4-二甲基苯胺(DMA)残留量的方法。样品经缓冲溶液(pH 9.0)稀释,乙腈和氯化钠进行蛋白沉淀、盐析提取后,通过N-丙基乙二胺(PSA)、C₁₈和无水硫酸镁进行分散固相萃取净化。净化液过0.22μm滤膜后,采用Agilent Eclipse XDB-C₁₈柱(150 mm×4.6 mm,5μm)分离,以0.15%甲酸溶液-乙腈为流动相进行梯度洗脱,采用电喷雾离子源正离子方式扫描,多反应监测模式进行检测,同位素内标法定量。结果表明,双甲脒、DMPF、DMF和DMA的线性范围为0～100μg/kg,相关系数(r)大于0.996,方法定量下限(S/N=10)分别为0.10、0.25、5.0、2.5μg/kg。对空白蜂王浆进行5、10、20μg/kg浓度水平的加标实验,回收率为77.0%～107%,相对标准偏差为2.0%～11%。该方法简便、快捷,适用于蜂王浆中双甲脒、DMPF及其代谢物残留量的同时测定。

Simultaneous Determination of Amitraz,Semiamitraz and Their Metabolites in Royal Jelly by Dispersive Solid-phase Extraction/Liquid Chromatography-Tandem Mass Spectrometry

An analytical method based on dispersive solid-phase extraction/liquid chromatography-tandem mass spectrometry (dSPE/LC-MS/MS ) was developed for the determination of amitraz,semiamitraz (DMPF ) and their metabolites N-(2,4-dimethylphenyl ) formamide (DMF ) and 2,4-dimethylaniline (DMA ) residues in royal jelly.The royal jelly samples were diluted with a buffer solution (pH 9.0 ),and the protein in royal jelly was precipitated with acetonitrile and NaCl.The acetonitrile supernatant was cleaned up with primary secondary amine (PSA ),C 18 and anhydrous MgSO 4 by dSPE method,then the supernatant solution was filtered through a nylon membrane (0.22 μm ) into a glass LC vial for LC-MS/MS analysis.The solution was separated on an Agilent Eclipse XDB-C 18 column (150 mm×4.6 mm,5 μm ) with acetonitrile-0.15 % formic acid solution as mobile phases by gradient elution,then determined by LC-MS/MS with electrospray ionization (ESI ) in positive ion scanning mode under multiple reaction monitoring (MRM ) mode,and finally quantified by isotope internal standard method.Results showed that there were good linear relationships for amitraz,DMPF,DMF and DMA in the concentration range of 0-100 μg/kg with their correlation coefficients (r ) more than 0.996.The limits of quantitation ( S/N =10 ) for the analytes were 0.10,0.25,5.0 and 2.5 μg/kg,respectively.The spiked recoveries at three levels of 5,10 and 20 μg/kg were in the range of 77.0 %-107 % with relative standard deviations (RSD ) of 2.0 %-11 %.This method was rapid and convenient,and was suitable for the simultaneous determination of amitraz,DMPF and their metabolites residues in royal jelly samples.