Separation and Enrichment of Selected Polar and Non-Polar Organic Micro-Pollutants—The Dual Nature of Quaternary Ammonium Ionic Liquid

Abstract

In this study, the dual nature of quaternary ammonium ionic liquid–didecyldimethylammonium perchlorate, [DDA][ClO4], was evaluated. A novel and sensitive in situ ionic liquid dispersive liquid–liquid microextraction method (in situ IL-DLLME) combined with magnetic retrieval (MR) was applied to enrich and separate selected organic micro-pollutants, both polar and non-polar. The magnetic support relied on using unmodified magnetic nanoparticles (MNPs) prepared by the co-precipitation of Fe2+/Fe3+ (Fe3O4). The separation technique was on-lined with high-performance liquid chromatography (HPLC–DAD) verified by inverse gas chromatography. An anion exchanger, NaClO4, was added to form an in situ hydrophobic IL. The fine droplets of [DDA][ClO4], molded in aqueous samples, functioned as an extractant for isolating the studied compounds. Then the carrier MNPs were added to separate the IL from the water matrix. The supernatant-free sample was desorbed in acetonitrile (MeCN) and injected into the HPLC system. The applicability of [DDA][ClO4] as an extraction solvent in the MR in situ IL-DLLME method was checked by the selectivity parameters (Sij∞) at infinite dilution. The detection limit (LOD) ranged from 0.011 to 0.079 µg L−1 for PAHs and from 0.012 to 0.020 µg L−1 for benzophenones. The method showed good linearity with correlation coefficients (r2) ranging from 0.9995 to 0.9999.