Simultaneous determination of four phthalate esters in bottled water using ultrasound-assisted dispersive liquid-liquid microextraction followed by GC-FID detection.

A simple and rapid sample pretreatment procedure based on ultrasound-assisted dispersive liquid-liquid microextraction is proposed for the determination of four phthalate esters (dibutyl phthalate, butyl benzyl phthalate, diisooctyl phthalate, dioctyl phthalate) in bottled water samples using gas chromatography-flame ionization detection. An ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using less disperser solvent, which markedly increased the extraction efficiency and reduced the equilibrium time. Under optimum conditions, the enrichment factor of the four analytes ranged from 490- to 530-fold and the recovery ranged from 84.8%∼104.7%. A good linear relationship between the peak area and the concentration of analytes was obtained in the range of 6.9∼444 μg L(-1). Intra-assay and inter-assay precision expressed as relative standard deviation (RSD) were in the range of 1.4∼2.0% and 3.0∼3.7%, respectively. This method offers a good alternative for routine analysis due to its simplicity and reliability.