采用高效液相色谱法测定美白祛斑化妆品中氨甲环酸的含量。0.500 0 g样品经饱和氯化钠溶液-甲醇（1+1）混合液20 mL超声提取5 min，离心后，上清液于45℃水浴氮吹浓缩至近干，再加入1 g·L^-1丹酰氯溶液500 μL和100 mmol·L^-1碳酸氢钠溶液500 μL进行衍生化反应5 min，冷却后，过0.22 μm微孔滤膜。以Zorbax SB C₁₈色谱柱为固定相，用乙腈和0.1%（体积分数）甲酸溶液以不同比例混合的溶液为流动相进行梯度洗脱，在检测波长250 nm处进行测定。氨甲环酸的质量浓度在1.0~100.0 mg·L^-1内与其对应的峰面积呈线性关系，检出限（3S/N）为0.3 mg·kg^-1。方法用于美白祛斑化妆品样品的分析，加标回收率为90.8%~98.0%，测定值的相对标准偏差（n=6）为2.0%~2.8%。

HPLC was applied to the determination of tranexamic acid in whitening freckle cosmetics. The sample (0.500 0 g) was extracted ultrasonically with 20 mL of mixture of saturated sodium chloride solution and methanol (1+1) for 5 min. After centrifugation,the supernatant was evaporated to near dryness by N₂-blowing at 45℃ in a water bath. 1 g·L^-1 dansyl chloride solution (500 μL) and 100 mmol·L^-1 NaHCO₃ solution (500 μL) were added to bring derivatization reaction for 5 min. After cooling, the solution was filtered on 0.22 μm microporous membrane. Zorbax SB C₁₈ chromatographic column was used as stationary phase, and the mixed solution of acetonitrile and 0.1% (φ) formic acid solution mixed in different ratios was used as mobile phase in gradient elution. Detection at 250 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of tranexamic acid was kept in the range of 1.0-100.0 mg·L^-1, with detection limit (3S/N) of 0.3 mg·kg^-1. The proposed method was applied to the analysis of samples of whitening freckle cosmetics, giving values of recovery and RSDs (n=6) in the ranges of 90.8%-98.0% and 2.0%-2.8% respectively.