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Retrieval of the Extraction Solvent by Magnetic Particles for Dispersive Liquid–Liquid Microextraction of UV Filters

A simple dispersive liquid–liquid microextraction (DLLME) method, based on retrieval of the extraction solvent by magnetic particles and followed by HPLC–UV analysis, was proposed for the determination of UV filters in environmental water samples. The new method uses vortex agitation in the DLLME process to achieve rapid equilibrium. Another feature of the proposed method is that the retrieval of the extraction solvent is accomplished by functionalized magnetic particles rather than by special designed vessels or refrigeration and thawing process associated with DLLME when low-density extraction solvent was used. The parameters that may influence the extraction, including vortex time, volume of extraction solvent, weight of the magnetic particles, volume of desorption solvent, pH, and ionic concentration of the sample solution, were investigated in detail. Under the optimized conditions, the limits of detection for the target UV filters were in range of 0.7–12.3 ng mL−1. The results also demonstrated good linearity and precision, with the regression coefficients above 0.9989 and the RSDs below 4.4%, respectively.