离子对色谱法测定化妆品中的苯酚磺酸锌

建立了离子对色谱测定不同基质化妆品中苯酚磺酸锌的分析方法。水剂类和香波类化妆品用20%乙腈水溶液提取,膏霜类和散粉类用80%乙腈水溶液提取,唇膏类加四氢呋喃并用80%乙腈水溶液提取,提取液离心、过滤处理。以四丁基氢氧化铵为离子对试剂,考察了苯酚磺酸锌在离子对色谱中的保留行为并优化了最佳色谱条件:以Kromasil C18(4.6 mm×250 mm,5μm)色谱柱分离,流动相为5 mmol/L四丁基氢氧化铵+25 mmol/L磷酸二氢钠缓冲溶液(pH 2.5)-乙腈(80∶20),等度洗脱,流速1.0 mL/min,柱温30℃,检测波长230 nm。该方法对苯酚磺酸锌的定量下限为:水剂和香波基质中为24 mg/kg、膏霜和唇膏基质中为120 mg/kg、散粉基质中为60 mg/kg,在0.5～50 mg/L范围内,苯酚磺酸锌的线性关系良好,相关系数为0.999 8。在低、中、高3个加标水平下,苯酚磺酸锌的平均回收率为94%～99%,相对标准偏差为0.57%～3.9%。该方法快速、简便、准确,可用于化妆品中苯酚磺酸锌的测定。

Determination of Zinc 4-Hydroxybenzene Sulphonate in Cosmetics by Ion-pair Chromatography

An ion-pair chromatographic method was developed for the determination of zinc 4-hydroxybenzene sulphonate in cosmetics with different matrixes.Lotion and shampoo samples were ultrasonically extracted with 20% acetonitrile aqueous solution,cream and powder samples were ultrasonically extracted with 80% acetonitrile aqueous solution,and lipstick samples were ultrasonically extracted with tetrahydrofuran and 80% acetonitrile aqueous solution,and then the extracts were centrifuged and filtered.Using tetrabutylammonium hydroxide as an ion-pair reagent,the retention behavior of zinc 4-hydroxybenzene sulphonate and the optimum chromatographic conditions were investigated.The optimal conditions were as follows:stationary phase:Kromasil C18(4.6 mm×250 mm,5 μm),mobile phase:A(5 mmol/L tetrabutylammonium hydroxide and 25 mmol/L sodium dihydrogen phosphate at pH 2.5):B(acetonitrile)=80:20,flow rate:1.0 mL/min,column temperature:30 ℃,detection wavelength:230 nm.Under the optimal conditions,the quantitation limits of zinc 4-hydroxybenzene sulphonate were 24 mg/kg for lotion and shampoo,120 mg/kg for cream and lipstick,and 60 mg/kg for powder.The calibration curve of zinc 4-hydroxybenzene sulphonate was linear in the range of 0.5-50 mg/L with a correlation coefficient of 0.999 8.The average recoveries at three spiked levels were between 94% and 99%,with relative standard deviations of 0.57%-3.9%.The method was rapid,simple and accurate,and could be used for the determination of zinc 4-hydroxybenzene sulphonate in cosmetics.