流動電位検出/イオン会合滴定法による陰イオン界面活性剤の迅速定量

An ion-association titration method coupled with a streaming potential detector was developed for the determination of anionic surfactants in a one-phase aqueous system. The titrant, benzethonium chloride (Hyamine) ion, was added to an anionic surfactant solution. The potential then changed from negative to positive along with an increase in the added titrant. The end point was read from an inflection point of a diffrential curve. The usual samples were titrated within 10 min. Anionic surfactants at concentrations from 10(-5)10(-3) mol dm(-3) could be determined by the proposed method. The relative standard deviations of various anionic surfactants were 0.20.6%. The proposed method was applied to the determination of various anionic surfactants and anionic surfactants in commercial detergents. The results obtained for practical samples were in good agreement with those of the JIS titration method (Epton method).

新しい流動電位検出器を用いたイオン会合滴定法による陰イオン界面活性剤の迅速定量法を開発した.陰イオン界面活性剤を陽イオン界面活性剤で滴定すると, 流動電位が負から正に変化することを用いて終点検出を行うという非常に簡単なもので, 更にクロロホルム溶媒を用いない水溶液系という特徴を有する.測定条件の最適化を行い, 10(-5)～10(-3)Mの濃度範囲の陰イオン界面活性剤を相対標準偏差0.2～0.5%と高精度で, 迅速自動定量 (10分/件) できることが分かった.陰イオン界面活性剤の各種標準及び実際試料について応用した結果, 定量値はJIS法 (Epton法) と非常に良い一致を示した.