夜蓝与阴离子表面活性剂在水溶液中显色反应——吸光光度法测定环境水样中阴离子表面活性剂

STUDIES ON THE COLOUR REACTION OF NIGHT BLUE WITH ANIONIC SURFACTANTS IN AQUEOUS SOLUTION-SPECTROPHOTOMETRIC DETERMINATION OF ANIONIC SURFACTANTS IN ENVIRONMENTAL WATER SAMPLES

在聚乙烯醇存在的1.8mol/L磷酸溶液中,夜蓝与阴离子表面活性剂形成离子缔合物。溶液由绿色变为蓝色,可用于水相直接光度测定阴离子表面活性剂。最大吸收波长555nm,摩尔吸光系数分别为5.72×10~4L·mol^(-1)·cm^(-1)(十二烷基苯磺酸钠),5.77×10~4 L·mol^(-1)·cm^(-1)(十二烷基硫酸钠),4.36×10~4 L·mol^(-1)·cm^(-1)(十二烷基磺酸钠)。方法简便、快速,具有良好的选择性。可用于河水和生活废水中10^(-6)—10^(-7)mol/L阴离子表面活性剂的测定。

A spectrophotometric method has been developed for the determination of anionic surfactants based on the formation of ion-associate compounds of night blue with anionic surfactants in aqueous solution in the presence of polyvinyl alcohol. The desirable acidity ranges from. 1.8 to 2.0mol/L of H_3PO_4. The maximum absorption exhibits at 555nm and the molar absorptivities are 5.72 ×10~4L·mol^(-1)·cm^(-1) for dodecylbenzenesulfonate, 5.77×10~4L·mol^(-1) ·cm^(-1) for dodecylsulfate and 4.36×10~4 L· mol^(-1)·cm^(-1) for dodecylsulfonate. The effect of coexisting ion (>20) and detergent additive was examined in detail by the standard procedure. The result indicated that the colour reaction sensitivity and selectivity are fairly good and the method can be applied to direct spectrophotometric determination of aniomic surfactants in river water and waste water. The recovery is 94％—106％ and the coefficient of variation ±1.73％ (n=11).