engleski

Potentiometric Determination of Anionic Surfactants in Formulations Containing Cocoamidopropyl Betaine

The application of surfactant sensor based on hexadecyltrioctadecylammonium-tetraphenylborate (HTA-TPB) for the potentiometric titration of anionic surfactant (SLES) in the presence of amphoteric surfactant (CAPB) is described. Standard solution of 1, 3-didecyl-2- methylimidazolium chloride (DMIC) was used as titrant (c = 2 mM). Amphoteric surfactants exhibit properties of anionic surfactants (AS) at high pH values ; therefore, the exact titrimetric determination of AS in the presence of amphoteric surfactants is strongly pH dependent and should be performed at pH 4. The accuracy of this determination depends on the SLES:CAPB ratio, and its accuracy decreases with an increasing CAPB content. The significant interfering effect of CAPB on the SLES determination was evidenced when the SLES:CAPB ratio was higher than 1:1. The normal AS to amphoteric surfactant ratio for commercial products is in the range of 1:1 to 2:1, and these ratios result in recoveries of 96 - 100 %.

ion sensitive sensor; PVC membrane; anionic surfactant; amphoteric surfactant; potentiometric titration; detergent products; personal care products

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