采用离子色谱-质谱法测定化妆品中羟乙二磷酸的含量。化妆品样品0.500 g，用3.0 mol·L^-1乙酸溶液50 mL超声提取15 min，冷却后，用3.0 mol·L^-1乙酸溶液定容至100 mL。移取上述溶液10 mL过0.22 μm尼龙滤膜后，再过Oasis HLB固相萃取小柱净化。以IonPac AS11-HC分析柱（250 mm×4 mm）为分离柱，氢氧化钾溶液为淋洗液，采用电喷雾负离子源选择反应监测模式检测。羟乙二磷酸的质量浓度在0.01~5.00 mg·L^-1内与其对应的峰面积呈线性关系，检出限（3S/N）为0.5 mg·kg^-1。在2.0，4.0，10.0，1 000 mg·kg^-1等4个浓度水平进行加标回收试验，回收率为92.0%~103%，测定值的相对标准偏差（n=6）为3.9%~8.1%。

IC-MS was applied to the determination of etidronic acid in cosmetics. The cosmetic sample (0.500 g) was extracted ultrasonically with 50 mL of 3.0 mol·L^-1 acetic acid solution for 15 min. After cooling, the solution was diluted to 100 mL with 3.0 mol·L^-1 acetic acid solution. An aliquot (10 mL) of the above sample solution was taken and filtered on 0.22 μm nylon filtering membrane. The filtrate was purified with Oasis HLB solid phase extraction column. IonPac AS11-HC analytical column (250 mm×4 mm) was used for chromatographic separation, and potassium hydroxide solution was used as eluant. ESI^- and the selected reaction monitor mode were adopted in MS. Linear relationship between values of peak area and mass concentration of etidronic acid was kept in the range of 0.01-5.00 mg·L^-1, with detection limit (3S/N) of 0.5 mg·kg^-1. Tests for recovery were made by standard addition method at 4 concentration levels of 2.0, 4.0, 10.0, 1 000 mg·kg^-1, giving values of recovery and RSD's (n=6) in the ranges of 92.0%-103% and 3.9%-8.1% respectively.