engleski

Simultaneous potentiometric determination of cationic and ethoxylated nonionic surfactants by use of a surfactant sensor

A sensitive potentiometric surfactant sensor based on 1, 3-didecyl-2-methylimidazolium-tetraphenylborate as a sensing ion-pair element served as an end-point detector in ion-pair surfactant potentiometric titrations using sodium tetraphenylborate as titrant. A few mixtures containing a cationic and ethoxylated nonionic surfactant were titrated potentiometrically. Barium ions forms pseudocationic complex with ethoxylated nonionic surfactant that can be titrated simultaneously with cationic surfactant using the same anionic titrant. Due to differences in hydrophobicity of both, nonionic and cationic surfactant investigated, ion associates formed during the titration revealed different stability constants resulting in two, more or less pronounced, analytically usable inflexions in the titration curve. The sensor showed satisfactory analytical performances within a pH range of two through eleven and was tested on several formulated powdered and liquid detergent products of various composition complexity too.

surfactant sensor; cationic surfactant; ethoxylated nonionic surfactant; potentiometric titration

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