水中阴离子表面活性剂的测定

Determination of Anionic Surfactants in Water

偶氮红两相滴定法在ｐＨ＝７．５的条件下，能测定水和废水中的各种阴离子表面活性剂的摩尔浓度。本文通过对硫酸盐、磺酸盐、苯磷酸盐、肥皂和磷酸盐等各类阴离子表面活性剂的测定，以及干扰试验和实际水样测定，表明此法优于亚甲基蓝分光光度法。方法的变异系数为１．０％（ｎ＝１１），最小检出浓度０．０５２ｍｇ／Ｌ（ｎ＝２１），加标回收率９２．１％－１１０．２％，平均１００．６％（（ｎ＝１４）。建议水中阴离子表面活性剂用摩尔浓度或ＰＳＡＡ表示。

The molar concentration of various kinds ofanionic surfactants in water and wastewater weredetermined at pH =7. 5 with azophloxine twophase titration. The results of determination ofanionic surfactants such as sulfates, sulfonates,benzesulfonates, soap and phosphates etc, withazophloxine titration and methylene blue photometry, respectively, were compared and the interference tests and actual samples analysis wereperformed. All results show that the azophloxinetitration was superior to the methylene blue photometry. The coefficient of variation was 1. 0%(n = 11 ); minimum detectabl6 concentration,0. 052 mg/L (n= 21 );recovery of standard addition, 92. 1 % - 110. 2 % on average 100. 6% (n=14). It was suggested that the concentration ofanionic surfactants in water should be expressedin molar concentration or PSAA, in stead of mg/L.