Development of a cloud point extraction method for the determination of phenolic compounds in environmental water samples coupled with high-performance liquid chromatography.

A method based on ultrasound-assisted cloud point extraction (CPE) was developed for the determination of phenolic compounds in water samples by high-performance liquid chromatography coupled with diode array detection (DAD) (HPLC-DAD). A nonionic surfactant, Tergitol 15-S-7, was chosen as the surfactant. The parameters affecting the CPE efficiency, such as Tergitol 15-S-7 concentration, salt concentration, extraction temperature, incubation time, centrifugation time, ultrasonic time, sample pH, and dilution solvent were systematically evaluated and optimized. Under the optimum experimental conditions, the linear regression coefficients of the standard curves were greater than 0.9986 and the limits of detection were in the range of 1.7-6.0 μg/L. The method was shown to be reproducible and reliable with intraday and interday relative standard deviations lower than 4.0 and 5.8%, respectively. The recoveries for the addition of different concentrations of phenolic compounds to water samples were in the range of 81.1-109.4%.