Cloud Point Extraction and Preconcentration Procedures for Organic and RelatedPollutants of State Concern

摘要

A new extraction and preconcentration procedure for organic compounds originallypresent in aqueous or solid matrices (soil, coal) based upon the unique properties (i.e. solubilization and phase separation ('clouding') ability) of aqueous solutions of neutral surfactant micellar systems was evaluated. At low surfactant concentrations above the critical micelle concentration (CMC), typically below 15 wt%, micellar solutions of non-ionic surfactants can exist as homogeneous isotropic liquid phases. Phase separation can be induced in this concentration range by varying the temperature. In many such phase separations, the single isotropic micellar phase separates into two isotropic phases, both of which contain surfactant but which differ in total surfactant concentration. In the surfactant micellar-rich phase will be concentrated any hydrophobic organic components originally present in the sample subjected to the phase separation step. The factors that influence both the phase separation behavior and extraction efficiency (concentration factor and percent recovery) for model test solutes (phenols and polycyclic aromatic hydrocarbons) were critically assessed.