氘代同位素内标气相色谱-质谱法测定食用香精中的二甲苯麝香

建立了氘代同位素内标气相色谱-质谱测定食用香精中二甲苯麝香含量的分析方法。采用漩涡混合器混合样品,使样品基质均匀分散于萃取溶剂中,再使用超声波提取目标物,探讨了萃取溶剂种类、溶剂用量及超声时间等因素对目标物萃取效率的影响;之后使用GC-MS选择离子监测模式检测,氘代同位素内标法定量,分析了不同极性色谱柱对目标物分离的影响,确定了较佳的特征离子及其丰度比。在优化实验条件下,二甲苯麝香在0.025～0.5 mg/L范围内具有良好的线性关系,相关系数(r2)为0.999 6,平均回收率为94%～116%,相对标准偏差(RSD)为4.2%～6.5%,检出限为0.11 mg/kg,定量下限为0.38 mg/kg。该方法简便、快速、灵敏、准确,适合于食用香精中二甲苯麝香含量的测定。

Determination of Musk Xylene in Food Flavors by Gas Chromatography-Mass Spectrometry Based on Deuterium Isotope Internal Standard

A gas chromatography-mass spectrometric method based on deuterium isotope internal standard was developed for the rapid determination of musk xylene(MX) in food flavors.In order to disperse sample matrix into extraction solvent,samples were distributed by use of a vortex mixer,and then extracted for 20 min with an ultrasonic generator.The influences of solvent type,solvent consumption and ultrasonic time on extraction efficiencies of the target compounds were discussed.The analyte was quantitatively analyzed by deuterium isotope internal standard method under selected ion monitoring(SIM) mode.The influences of different polarity chromatographic columns on separation were analyzed,the characteristic ions and their abundances were determined.Under the optimal conditions,the calibration curve of MX was in the range of 0.025-0.5 mg/L with a correlation coefficient of 0.999 6.The average recoveries were in the range of 94%-116% with relative standard deviations of 4.2%-6.5%.The detection limit and quantitation limit of MX were 0.11 mg/kg and 0.38 mg/kg,respectively.The results showed that the method was simple,rapid,sensitive and accurate,and was suitable for the rapid determination of MX in food flavors.