高效液相色谱法测定牙膏中防腐剂含量

Determination of preservatives in toothpaste by high performance liquid chromatography

为管理限制牙膏中防腐剂的种类与用量,提升牙膏质量,研究利用高效液相色谱法测定牙膏中防腐剂的含量。用对羟基苯甲酸甲酯、对羟基苯甲酸乙酯以及苯甲酸等5种试剂制备防腐剂混合标准溶液,利用乙腈等溶液处理牙膏样本,采用高效液相色谱仪,以磷酸二氢钠溶液、甲醇与乙腈混合溶液为流动相,在柱温为室温,进样量为5μL,流速为1.5 mL/min的条件下测定混合标准溶液与牙膏样本,并根据混合标准溶液色谱峰的保留时间与面积绘制标准曲线。结果显示:流动相内磷酸二氢钠溶液、甲醇与乙腈体积比为55∶25∶20的条件下,混合标准溶液的分离度最高;各类防腐剂回收率范围为88.68%~99.61%之间,相对标准偏差范围为0.39%~2.44%之间;重复性测试结果满足实际应用需求。

In order to manage and limit the types and amounts of preservatives in toothpaste and to improve the quality of toothpaste,a method for determining the content of preservatives in toothpaste by high performance liquid chromatography was studied.The mixed standard solution of preservatives was prepared with five reagents including methylparaben,ethylparaben and benzoic acid,and the toothpaste samples were treated with solutions such as acetonitrile.Sodium dihydrogen phosphate solution,methanol and acetonitrile mixed solution were used as mobile phases.The mixed standard solution and toothpaste samples were measured under the conditions that the column temperature,injection volume and flow rate were room temperature,5μL and 1.5 mL/min,respectively.A standard curve was drawn according to retention time and area of chromatographic peak of mixed standard solution.The results show that:under the condition that the ratio of sodium dihydrogen phosphate solution,methanol and acetonitrile in the mobile phase is 55∶25∶20,the separation degree of the mixed standard solution is the highest.The recovery rate of various preservatives fluctuates between 88.68%and 99.61%,and the relative standard deviation fluctuates between 0.39%and 2.44%.The repeatability test results meet the needs of practical applications.