Dispersive micro-solid phase extraction based on self-assembling, ionic liquid-coated magnetic particles for the determination of clofentezine and chlorfenapyr in environmental water samples

Two ionic liquid-coated-Fe₃O₄ magnetic particles (IL-Fe₃O₄ MPs) were developed for use in two types of dispersive micro-solid phase extraction (D-μ-SPE) for the high-performance liquid chromatographic analysis of clofentezine and chlorfenapyr in environmental water samples. Self-assembling IL-Fe₃O₄ MPs were used in D-μ-SPE as adsorbents. Two D-μ-SPE extraction methods, namely, direct dispersive micro-solid phase extraction (d-D-μ-SPE) and in situ solvent formation-based dispersive micro-solid phase extraction (ISF-D-μ-SPE), were proposed, using [C₈MIM][PF₆] to extract analytes through two pathways. Lower IL doses were required in the extraction process compared with those in other IL-based methods. Fe ₃O₄ MPs can also be recycled and reused after extraction and are thus environmentally friendly. These newly developed methods were demonstrated to be feasible for use in the quantitation of clofentezine and chlorfenapyr at trace levels, with lower limit of detection values ranging from 0.4 to 0.5 ng mL^-1 for d-D-μ-SPE and 0.4 ng mL^-1 for ISF-D-μ-SPE. Finally, relative standard deviations of less than 6.0% were obtained.