A Natural Monoterpene Enol for Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Droplets for Determination of Benzophenone Compounds in Water Samples

In the current study, an effective and simple procedure of extraction for the four benzophenone compounds from water samples was achieved by dispersive liquid–liquid microextraction (DLLME) based on the solidification of floating organic droplets (SFO) with a natural monoterpene enol as the extractant. As a natural, high solidification point, inexpensive, and environmentally friendly hydrophobic solvent, α−terpineol was selected firstly as an extractant for DLLME and could be collected and transferred easily after extraction by solidification at a lower temperature. Several main parameters closely related to extraction efficiencies, such as volume of extractant, extraction time, pH and salt concentration of the sample solution, temperature, and time of the solidification process, were investigated in detail. The results showed that the established method had good extraction performance for benzophenone compounds with enrichment factors in the range of 29–47. Furthermore, the linearities were over the range of 2–2000 µg/L, and the limits of detection were 0.12–0.53 µg/L for four benzophenone compounds. The recoveries ranged from 80.2% to 108.4%, with RSDs (intra- and inter-assay) less than 8.5%. At last, the method applicability was investigated by the determination of the benzophenone compounds in aqueous solutions, and satisfactory recoveries (83.0–107.0%) were acquired. Taken together, α−terpineol, a natural monoterpene enol, was first used as an extractant of DLLME-SFO, which provided an alternative method with simplicity and rapidity for the determination of benzophenone compounds in aqueous samples.