Reverse flow injection analysis of trace amounts of anionic surfactants in seawater without liquid–liquid extraction

Abstract

  In order to control the pollution by anionic surfactants in seawater, a simple, accurate and sensitive reverse flow injection (rFIA) spectrophotometric method for the determination of anionic surfactants in seawater is suggested in this paper. Sodium dodecylbenzenesulfonate (LAS) was selected as the reference anionic surfactant. The method is based on the ion associate formed between LAS and Ethyl Violet. The absorbance of the complex is measured by optical detector at 585 nm. Chemical factors and rFIA variables affecting the system are also discussed. Under the optimal conditions, the linear range of this method was 25.0–400.0 μg/l; the detection limit was 2.4 μg/l; the relative standard deviation was 0.38%. This method is suitable for automatic and continuous analysis, and was successfully applied to determine the content of anionic surfactants in seawater.