分光光度法测定水中十六烷基三甲基溴化铵的含量

Spectrophotometric determination of trace amounts of cetyltrimethyl ammonium bromide in water solution

通过可见光谱法研究了十六烷基三甲基溴化铵（CTAB）与甲基橙（MO）的显色反应，提出采用分光光度法测定水中十六烷基三甲基溴化铵的方法。结果表明，在体积分数为20％乙醇水溶液中，CTAB与MO形成1：1的黄色离子缔合物，最大吸收波长位于470nm处，摩尔吸光系数ε=1．404×10^3L·mol^-1·cm^-1．CTAB的浓度在0～6．0×10^-4 mol／L符合比耳定律。方法简便，快速，适于水样中CTAB的测定。

The spectrophotometric method for the determination of cetyltrimethylammoniun bromide （CRAB） was proposed by studying the interaction of cationic surfactants cetyltrimethylammonium bromide with methyl orange. The results showed that the 1 ： 1 associated ion pairs with yellow color were formed from electrostatic interaction of cetyltrimethylammonium bromide with methyl orange in ethanol solution, λmax = 470 nm and ε = 1.404 ×10^3 L·mol^-1·cm^-1. When the CRAB concentration ranges between 0～6.0× 10^-4 mol/L, the color absorption follows Beer＇s Law. The method has been applied to determine the trace cetyltrimethylammonium bromide in water.