Determination of Substituted Benzenes in Water by Salting-Out Phase Separation Microextraction Coupled to High Performance Liquid Chromatography

A trace analytical method of o-chloropheno, chlorobenzene and ethylbenzene in water had been developed by using salting-out phase separation microextraction coupled to high performance liquid chromatography. A Diamonsil C18 column (5μm, 250×4.6mm i.d.) was used for separation at 30°C with detection wavelength at 220nm; The mobile phase was a mixture of methanol and water (the ratio of volume was 53:47), flow rate was 1.0 mL/min. The optimal extraction conditions: volume of water was 18mL; extraction solvent was 300μL iso-butyl alcohol; quantity of ammonium sulfate was 14g. Good linearity was verified in a range of 0.006-138.4 mg/L for each analyte. LODs of o-chlorophenol, chlorobenzene and ethylbenzene were 0.07, 0.2, 6.4μg/L, respectively. The average recovery of substituted benzenes ranged from 71.66% to 92.96% with the relative standard deviations (RSDs) (n=6) below 5.17%.