化妆品样品经甲醇超声提取15 min,离心分离取上清液经Agilent Extend C18柱(250 mm×4.6 mm,5 μm)分离,用甲醇与乙酸(2+98)溶液按体积比90比10混合作为流动相进行淋洗,于波长355 nm处用二极管阵列检测器进行测定,阳性样品经质谱确证。维甲酸和异维甲酸的定性离子对为m/z 299/255和299/199。维甲酸和异维甲酸的质量浓度均在1.00~100 mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.1 mg·L-1。以3种不同类型的化妆品样品为基体,加入2种不同浓度的标准溶液做回收试验,测得维甲酸和异维甲酸回收率分别在97.2%~105%和97.2%~111%之间,相对标准偏差(n=6)均小于2.5%。

The sample was ultrasonically extracted with methanol for 15 min, after centrifugation, the supernatant obtained was used for HPLC determination. Agilent Extend C18 column (250 mm×4.6 mm, 5μm) was used as chromatographic column, and mixture of methanol and acetic acid (2+98) solution, mixed in volumic ratio of 90 to 10, was used as mobile phase. Diode array detector and the wavelength of 355 nm was adopted in the determination. The positive sample was confirmed by MS. Ion pairs used for qualitative analysis were m/z 299/255 for tretinoin and m/z 299/199 for isotretinoin. Linear relationships between values of peak area and mass concentration of tretinoin and isotretinoin were obtained in the same range of 1.00-100 mg·L-1, with same value of limit of detection (3S/N) of 0.1 mg·L-1. Tests for recovery and precision were made by addition of standard solution in 2 different concentration levels to 3 kinds of cosmetic samples, values of recovery obtained were in the ranges of 97.2%-105% for tretinoin and 97.2%-111% for iso-tretinoin with RSD′s (n=6) less than 2.5%.