电位滴定法测定化妆品中碱金属卤酸盐

Determination of Alkali Metal Halides in Cosmetics by Potentiometric Titration Method

建立了电位滴定法测定化妆品中碱金属卤酸盐含量的方法.在酸性条件下卤酸盐被锌粉还原,对所形成的卤化物采用硝酸银溶液进行电位滴定.试验结果表明,在0.03％～3.41％（以氯酸根离子计）浓度（质量分数）范围内,碱金属卤酸盐的加标回收率为80.0％～99.7％,相对标准偏差（RSD）≤10％;定性检出限为0.03％（质量分数）,最低定量限为0.10％（质量分数）.电位滴定法操作简便、结果准确、精密度高、重现性好,适用于化妆品中碱金属卤酸盐的测定.

A potentiometric titration method was established for determination of the alkali metal halides in cosmetics.First,the alkali metal halides were reduced by zinc power under acid conditions,then,the formed halides were measured by potentiometric titration using a silver nitrate solution.Based on the amount of chlorate ions,the recovery of the method was in the range of 80.0％ to 99.7％ at the concentration of 0.03％ to 3.41％.Additionally,the detection and quantification limits were 0.03％ and 0.10％,respectively.The results demonstrated that the procedure was accurate,precise and reproducible （relative stand ard deviation not more than 10％）,which can be applied for the determination of alkali metal halides in different types of cosmetic.