Development of supramolecular solvent based microextraction prior to high performance liquid chromatography for simultaneous determination of phenols in environmental water

Abstract

A simple and eco-friendly preconcentration method, supramolecular solvent (SUPRAS) based microextraction, combined with high performance liquid chromatography (HPLC) has been developed for the determination of phenols in water. Seven phenols include phenol, 4-nitrophenol, 2-chlorophenol, 2-nitrophenol, 4-chloro-3-methylphenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The SUPRAS fulfills the requirement of green and sustainable analytical chemistry in that surfactant was used for extraction in mild conditions without the requirement of heating, organic solvent and acid addition. The SUPRAS was produced from micelles of anionic surfactant (sodium dodecyl sulfate; SDS) and cationic surfactant (tetrabutylammonium bromide; TBABr) at the molar ratio of 1 : 3. After AlCl₃ addition, a turbid solution was observed due to the neutralization charge of micellar head groups with the counterion (Al³⁺) of salt, resulting in liquid–liquid separation. After centrifugation, the SUPRAS was separated by floating on the top layer. Under the optimum conditions, a high enrichment factor (25 to 64), low limit of detection (1 to 4 μg L⁻¹) and good repeatability (RSD ≤ 10.1%) were obtained. The SUPRAS-HPLC was successfully applied for the determination of the studied phenols in environmental water samples with good recoveries (82 to 105%).