Direct Supercritical Fluid Extraction of Alkylphenols from Spiked and Wastewater Samples Using Extraction Cells Equipped with Hydrophobic Membrane‐Assemblies

Abstract

Akylphenols (4‐nonylphenol, 4‐(1,1,3,3‐tetramethylbutyl)‐phenol and 2,6‐bis(1,1‐dimethylethyl)‐4‐ethylphenol) have been directly extracted from water samples using neat supercritical carbon dioxide and collected on an octadecyl silica (ODS) solid phase trap. The extraction cells were equipped with home‐built assemblies containing hydrophobic membranes. The assemblies were inserted at each end of the extraction cell to maintain the water sample inside the extraction cell. In this case, no sample pre‐treatment step, such as freeze‐drying or solid phase extraction (SPE) of the water samples, was needed prior to the supercritical fluid extraction (SFE). Distilled water, spiked with an alkylphenol standard solution at a level of 25 mg/L, was used as a model sample to investigate extraction efficiency as well as collection capability. To obtain quantitative recoveries, a fractionated extraction/elution procedure was adopted. The alkyl‐phenols were finally determined in a leachate water sample and in an industrial effluent sample, where the levels were in the range of 0.2–10 mg/L.

Keywords:

• Direct supercritical fluid extraction
• Aqueous samples
• Alkylphenols