Ultrasonic extraction and colorimetric determination of anionic surfactants in marine sediments by the ethyl violet method

Abstract

In this paper a procedure for analysing anionic surfactants (AS) in marine sediments is described. The procedure is based on the ultrasonic extraction of AS by water and their colorimetric determination by the Ethyl Violet method (EVM). The ultrasonic treatment provides the water extraction of AS from marine sediments in about 1 h. Then the EVM, already applied for AS determination in sea-water, was extended to determine AS in marine sediments. Owing to the complexity of the interactions between fulvic acids and AS present in the aqueous extracts, the colorimetric determination of AS must be performed by the standard additions method. The described procedure gives recoveries between 80 and 100%.