An efficient, inexpensive and environmentally benign ultrasound-assisted supramolecularsolvent-based microextraction technique combined with high-performance liquid chromatography was used for the determination of chlorophenols in environmental water samples. Different factors such as amount of decanoic acid, volume of tetrahydrofuran, pH of the sample, ultrasound time and ionic strength were investigated and optimized. The optimized extraction conditions were 60 mg decanoic acid, 1.5 mL tetrahydrofuran, 3 min ultrasound time, without salt addition. Under this condition, the extraction recoveries were 83.0–89.3 with preconcentration factors of 94–102. The calibration curves were linear from 5.0–400.0 ng/mL with square of the correlation coefficient higher than 0.9998 and the limits of detection were between 1.5–2.0 ng/mL. The values of intra- and inter-day relative standard deviations were 3.2–6.0 and 7.3–8.0%, respectively. Analysis of different samples showed that the concentration of 2,5-dichlorophenol in Babolrood river water was 80.6 ng/mL.
