液相色谱-串联质谱法测定祛痘化妆品中5种硝基咪唑类化合物

Determination of five kinds of nitroimidazole compound in whelk dispelling cosmetics by liquid chromatographytandem mass spectrometry

采用液相色谱-串联质谱(LC-MS/MS)法建立了测定祛痘化妆品中5种硝基咪唑类化合物(甲硝唑(MNZ)、洛硝哒唑(RNZ)、二甲硝咪唑(DMZ)、羟基甲硝唑(MNZOH)和1-甲基-5-硝基-2-羟甲基咪唑(HMMNI))的方法。样品经乙酸乙酯提取,采用Hypersil GOLD C_(18)色谱柱(2.1 mm×100 mm,3μm)分离,依次用丙酮、甲醇和V(氨水):V(乙腈)=5:95的混合溶液淋洗,采用LC-MS/MS在多反应监测(MRM)正离子模式下检测,基质外标法定量。结果表明:MNZ,RNZ和DMZ在0~50μg/L内呈良好线性关系,MNZOH和HMMNI在0~100μg/L内呈良好线性关系;5种硝基咪唑药物线性相关系数R^2>0.99;在试样中进行3个水平的加标回收实验,平均回收率为84.3%~115.0%,相对标准偏差(RSD)为1.66%~10.30%(n=6),适用于祛痘化妆品中硝基咪唑类化合物的检测和确证需要。

A method for determination of five kinds of nitroimidazole compound （metronidazole （MNZ）, ronidazole （ RNZ）, dimetridazole （ DMZ）, hydroxyl metronidazole （MNZOH） and 2 - hydroxymethyl - 1 - methyl - 5 - nitroimidazole （HMMNI） ） in whelk dispelling cosmetics by liquid chromatography - tandem mass spectrometry （ LC - MS/MS） was established. The target analyte was extracted from the product sample with ethyl acetate as solvent,and the extract was separated on a Hypersil GOLD Cls column （2. 1 mm x 100 mm, 3 p,m）, sequentially eluted with acetone, methanol and blend solution with V（ ammonia water）： V（acetonitrile） = 5： 95, detected using LC -MS/MS in the multiple reaction monitoring （MRM） positive ion mode, and quantified by external standard matrix method. The results indicated that good linearity displays when mass concentration of MNZ, RNZ and DMZ is within 0 -50 txg/L, and when mass concentration of MNZOH and HMMNI is within 0 ~ 100 p.g/L. Linear correlation coefficient （R2 ） is higher than 0. 99. In the spiked test of three levels,the average recovery rate is in the range of 84. 3% -115.0% ,and relative standard deviation （RSD） is in the range of 1.66% - 10. 30% （n = 6）. This analysis method meets the testing requirements for detection and confirmation.