engleski

Potentiometric determination of soaps and mixtures of soaps with anionic surfactants using a new surfactant sensor

A newly synthesized sensing material, tetrahexadecylammonium dodecylsulfate was used for the construction of a coated wire-type surfactant sensitive electrode, using a PVC matrix and graphite-PTFE as the conducting substrate. The electrode was used for the potentiometric titration of mixtures of soaps with anionic surfactants. The standard solution of cationic surfactant cetyltrimethylammonium bromide (CTAB) was used as the titrant. The individual soaps were titrated in alkaline solution (pH 10.5), while for the titration of their mixtures with anionic surfactants two titrations of equal volumes of analyte were needed. By titration in alkaline solution both anionic surfactant and soap were detected, whereas the titration in acidic solution (pH 2.5) detected only anionic surfactants with strongly acidic groups. From the difference in titrant volume used for the alkaline and the acidic medium, the soap content in the mixture can be calculated.

surfactants ; potentiometric titration ; potentiometric sensor

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