Ultra-hydrophobic ionic liquid 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate supported hollow-fiber membrane liquid-liquid-liquid microextraction of chlorophenols.

An ultra-hydrophobic ionic liquid, 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIM][FAP]) was immobilized in the pores of a polypropylene hollow fiber for liquid-liquid-liquid microextraction (HF-LLLME) of chlorophenols (CPs) (4-chloro-3-methylphenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol). The analytes were first extracted from 10 ml of water sample into the ionic liquid membrane, and then were extracted back into 5 μl of sodium hydroxide aqueous solution in the hollow fiber channel. After extraction, the acceptor solution was directly injected into a high-performance liquid chromatographic system for analysis. Extraction parameters such as extraction time, salt concentration in the sample, the pH of the sample and acceptor phase, and stirring rate during extraction were investigated. The relative standard deviations of the analytes varied from 4 to 6%. Limits of detection of <0.5 ng/ml were obtained for the three analytes. The squared regression coefficients relating to the calibration curve were ≥0.9941. The proposed method was applied to the analysis of CPs in canal water.