高效液相色谱串联质谱法测定红糖中3-硝基丙酸

Determination of 3-Nitropropionic Acid in Brown Sugar by HPLC-MS/MS

建立了红糖中3-硝基丙酸的高效液相色谱串联质谱检测方法。红糖样品用乙醇-水溶解,涡旋振荡,离心后取上清液,用PWAX固相萃取柱净化,氮气吹干洗脱液,甲醇-甲酸水复溶后,用高效液相色谱串联质谱检测。采用Luma Omega C18柱(1.6μm,100mm×2.1mm),以甲醇和水为流动相进行分离,电喷雾负离子模式(ESI-),多反应监测(MRM)检测,外标法定量。结果表明,3-硝基丙酸在0.1~20μg/L浓度范围内线性关系良好(r=1.0000),该方法的检出限为0.057μg/kg,定量限为0.189μg/kg。在2.5、10、50μg/kg的加标水平下,3-硝基丙酸的平均回收率为79.2%~85.5%,相对标准偏差为5.2%~7.3%以下(n=6)。本方法操作简单、灵敏度高、结果准确,可用于红糖中3-硝基丙酸的残留量测定。

A method was developed for the determination of 3-nitropropionic acid in brown sugar by High Performance Liquid Chromatography Tandem Mass Spectrometry(HPLC-MS/MS).The sugar samples were extracted by ethanol-water solution,then vortex and centrifugate.The extracted solution was purified by the PWAX solid-phase extraction column,then the purified solution was concentrated by nitrogen,used methanol-water(0.1%formic acid)to dissolve.Chromatographic separation was achieved on Luma Omega C18 column(1.6μm,100 mm×2.1 mm).The mobile phase consisted of water and methanol,then analyzed by using HPLC-MS/MS in multiple reaction monitoring(MRM)mode via negative electrospray ionization.External standard method was used to determine 3-nitropropionic acid contents(0.1~20μg/L)with a good linear relationship(r=1.0000).The limit of quantification(LOQ)was 0.057μg/kg,the limit of quantification was 0.189μg/kg.The recoveries of acrylamide at three levels of 2.5,10,and 50μg/kg were from 79.2%to 85.5%with the relative standard deviations(RSDs)of 5.2%~7.3%(n=6)in brown sugar.The method was simple and characterized with acceptable sensitivity and accuracy to meet the requirements of the determination of 3-nitropropionic acid in brown sugar.