Simultaneous analysis of phthalate esters and pyrethroid insecticides in water samples by temperature-controlled ionic liquid dispersive liquid-phase microextraction combined with high-performance liquid chromatography

Abstract

A simple, rapid and efficient method is described for the simultaneous pre-concentration and determination of phthalate esters and pyrethroid insecticides in water samples by temperature controlled ionic liquid dispersive liquid phase microextraction in combination with high performance liquid chromatography. In this procedure, only ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate [C₈MIM][PF₆] was used for the enrichment. The proposed method successfully overcomes the disadvantages of conventional single drop liquid phase microextraction and dispersive liquid-liquid microextraction such as the instability of the suspending drop and the use of toxic solvents, and requires a smaller extraction volume. Factors such as volume of [C₈MIM][PF₆], sample pH, extraction time, centrifugation time, and temperature and salting-out effect were systematically investigated and optimized. The detection limits obtained for phthalate esters and pyrethroid insecticides were in the range of 0.23–0.47 μg L⁻¹ and the precisions were in the range of 2.2–5.9% (n = 6). Real water samples were used for validating the proposed method and satisfactory results were achieved.