Determination of anionic surface active agents using silica coated magnetite nanoparticles modified with cationic surfactant aggregates

The development of a novel methodology for extraction and preconcentration of the most commonly used anionic surface active agents (SAAs), linear alkylbenzene sulfonates (LAS), is presented herein. The present method, based on the use of silica–magnetite nanoparticles modified with cationic surfactant aggregates, was developed for determination of C10–C13 LAS homologues. The proposed methodology allowed quantitative recoveries of C10–C13 LAS homologues by using a reduced amount of magnetic nanoparticles. Limits of detection were in the range 0.8–1.9 μg L−1 for C10–C13 LAS homologues, while the repeatability, expressed as relative standard deviation (RSD), ranged from 2.0 to 3.9% (N = 6). Finally, the proposed method was successfully applied to the analysis of a variety of natural water samples.