Zur Anwendung des sog. modifizierten Dragendorff-Reagenses bei der Bestimmung von Kationtensiden im aquatischen Milieu

Abstract

Cation active surfactants of the distearyldimethyl-ammonium chloride type are precipitated, just as the anionic surfactants used in detergents, by the so-called modified Dragendorff reagent at the present time. However, only the cation-active surfactants dissolve in CHCl3 and CCl4 in the form of a coloured compound. Thus, they can be determined in spectrophotometrical way. The reagent was tested under different view points for its suitability and was then modified to the cation-active surfactants in a problemoriented manner. At the same time, the determination limit could be improved by the factor of 5 to 10 by using both derivative spectroscopy and back-correction. Cation-active surfactants can be quantitatively determined in waste waters, lightly contaminated sediments, as well as in heavily contaminated sewage sludges.