Determination of cationic surfactants in soil samples by the disulphine blue active substance (DBAS) procedure

Abstract

A method for the determination of cationic surfactants in soil samples was developed and applied to a biodegradation study. Five different cationic surfactants (benzalkonium chloride, 1-dodecyl-3-methylimidazolium bromide, didecyldimethylammonium bromide, trihexyl(tetradecyl)phosphonium bromide and trihexyl(tetradecyl)phosphonium chloride) were selected for the study with the developed method upon extraction from soil samples with methanol. The samples were subjected to analysis as disulphine blue active substances using a visible spectrophotometer. The limits of detection for the proposed method ranged from 2 to 27 μg/g, which enabled the determination of cationic surfactants in soil samples. The results obtained in the biodegradation study were confirmed using liquid chromatography coupled with tandem mass spectrometry.