顶空气相色谱-质谱联用法测定化妆品中α-氯甲苯

Determination of α-Chlorotoluene in Cosmetics by Headspace Gas Chromatography-Mass Spectrometry

该文建立了一种适用于含苯扎氯铵的化妆品中α-氯甲苯的测定方法。首先通过气相色谱-质谱联用法(GC-MS)剖析苯扎氯铵热分解产物的成分,确证了苯扎氯铵类化合物在气相进样口会分解产生α-氯甲苯。采用气液平衡的顶空进样方式,并通过优化顶空进样参数、色谱分离和质谱测定条件,建立了一种化妆品中α-氯甲苯的新型分析方法。选择顶空平衡温度和时间分别为80℃和30 min,样品于顶空瓶中用8 mL水和1.0g氯化钠分散,以HP-INNOWax色谱柱(60 m×0.25 mm×0.25μm)分离,采用选择离子监测模式(SIM)检测,外标法定量。结果显示:α-氯甲苯在0.01~5.00μg/mL质量浓度范围内与对应的峰面积呈良好的线性关系(r=0.999),方法检出限和定量下限分别为0.02μg/g和0.05μg/g,加标回收率为91.3%~98.8%,相对标准偏差(RSD)为1.5%~4.9%。该方法操作简便,快速,灵敏度高,专一性好,能有效解决现有方法假阳性干扰的问题,适用于各种化妆品中α-氯甲苯的准确测定。

A method was developed for the determination ofα-chlorotoluene in cosmetics containing benzalkonium chloride.Firstly,the thermal decomposition products of benzalkonium chloride was analyzed by gas chromatography-mass spectrometry(GC-MS).A phenomenon was confirmed that benzalkonium chloride and similar compounds will decompose intoα-chlorotoluene at the inlet of GC-MS.Then,a new analytical method forα-chlorotoluene in cosmuetics was developed by a headspace injection mode of gas-liquid equilibrium.The headspace sampling parameters,chromatographic separation and mass spectrometry conditions were optimized.The equilibrium temperature and time for headspace sampler were set at 80℃and 30 min,respectively.The sample was dissolved with 8 mL water and 1.0 g sodium chloride in headspace bottle.The analytes were separated on an HP-INNOWax column(60 m×0.25 mm×0.25μm),then detected in selectedion monitoring mode and quantified by external standard method.Results showed that the standard curves forα-chlorotoluene were linear over the concentration range of 0.01-5.00μg/mL with linear correlation coefficients(r)of 0.999.The detection limits and quantification limits of the method were 0.02μg/g and 0.05μg/g,respectively.The spiked recoveries ranged from 91.3%to 98.8%with relative standard deviations(RSDs)of 1.5%-4.9%.The method is simple,rapid,high sensitive and specific,and it is suitable for the determination ofα-chlorotoluene in cosmetics.