Centrifugeless ultrasound-assisted emulsification microextraction based on salting-out phenomenon followed by high-performance liquid chromatography for the simple determination of phthalate esters in aqueous samples.

A fast, sensitive, and centrifugeless ultrasound-assisted emulsification microextraction followed by a high-performance liquid chromatography method is developed for the determination of some phthalate esters in aqueous samples. In this method, a simple approach is followed to eliminate the centrifugation step in dispersive liquid-liquid microextraction using an organic solvent whose melting point is near the ambient temperature, consumption of the extracting solvent is efficiently reduced, and the overall extraction time was found to be only 7 min. The variables affecting the method are optimized. Under the optimal experimental conditions (75 μL of 1-undecanol, a flow rate of 2.0 mL/min, and an ultrasound irradiation of 1 min), the proposed method exhibits good preconcentration factors (52-97), low limits of detection (1.0-5.0 ng/mL), and linearities in the range of 5-1500 ng/mL (r2 ≥ 0.995). Finally, the method is successfully applied to the analysis of phthalate esters in the drinking and river water samples. To study the probable release of the phthalate esters from a polyethylene container into boiling water, the boiling water exposed to the polyethylene container was analyzed by the proposed method.