Surfactant-based ionic liquids for extraction of phenolic compounds combined with rapid quantification using capillary electrophoresis.

A rapid liquid phase extraction employing a novel hydrophobic surfactant-based room temperature ionic liquid (RTIL), tetrabutylphosphonium dioctyl sulfosuccinate ([4C4 P][AOT]), coupled with capillary electrophoretic-UV (CE-UV) detection is developed for removal and determination of phenolic compounds. The long-carbon-chain RTIL used is sparingly soluble in most solvents and can be used to replace volatile organic solvents. This fact, in combination with functional-surfactant-anions, is proposed to reduce the interfacial energy of the two immiscible liquid phases, resulting in highly efficient extraction of analytes. Several parameters that influence the extraction efficiencies, such as extraction time, RTIL type, pH value, and ionic strength of aqueous solutions, were investigated. It was found that, under acidic conditions, most of the investigated phenols were extracted from aqueous solution into the RTIL phase within 12 min. Good linearity was observed over the concentration range of 0.1-80.0 μg/mL for all phenols investigated. The precision of this method, expressed as RSD, was determined to be within 3.4-5.3% range. The LODs (S/N = 3) of the method were in the range of 0.047-0.257 μg/mL. The proposed methodology was successfully applied to determination of phenols in real water samples.