Hexafluoroisopropanol-mediated cloud point extraction of organic pollutants in water with analysis by high-performance liquid chromatography

A hexafluoroisopropanol (HFIP)-mediated cloud point extraction (CPE) system was established. A small amount of HFIP (even 1%, v/v) can dramatically reduce the cloud point of Triton X-100 (TX-100) aqueous solution (even to 1 A degrees C) and make liquid-liquid two-phase separation (coacervate phase and aqueous phase) occur at room temperature over a wide range of TX-100 concentration (0.5 similar to 10%, g/mL). HFIP-mediated coacervate phase has smaller volume (volume ratio is 1.8 similar to 8.9% relative to the volume of the total solution with 1 similar to 5% TX-100) and larger micelle aggregates (30 similar to 80 nm in diameter) compared to temperature-induced coacervate phase (volume ratio at 2.8 similar to 14.0%, the diameter of micelle aggregates at 5 similar to Z30 nm). HFIP-mediated CPE was coupled to high-performance liquid chromatography with ultraviolet detection (HPLC-UV) for the extraction and detection of organic pollutants in water, namely, polycyclic aromatic hydrocarbons (PAHs), fluoroquinolones (FQs), and sulfonamides (SAs) with different polarities, charges, and hydrogen-bonding properties. HFIP-mediated CPE provides much higher extraction rates (ERs) and enrichment factors (EFs) for FQs (91 similar to 106%, 50 similar to 59), PAHs (63 similar to 90%, 33 similar to 49), and SAs (26 similar to 55%, 16 similar to 34) compared with the temperature-induced one (ERs: 4 similar to 8% for FQs, 25 similar to 46% for PAHs, and 4 similar to 37% for SAs; EFs: 1 similar to 3 for FQs, 6 similar to 12 for PAHs, and 8 similar to 13 for SAs). The limit of detection ranges from 0.24 to 0.33 ng/mL for FQs, 0.04 to 0.38 ng/mL for PAHs, and 0.63 to 1.31 ng/mL for SAs. The proposed method was applied in the analysis of real water samples, and the recovery of 79.4 similar to 110.8% and the relative standard deviation of 0.2 similar to 16.3% were achieved for the three types of pollutants.