Solid-phase extraction and concentration of trace chlorophenols with extractant- impregnated membrane disks

Abstract

The solid-phase extraction and concentration of mono-, di-, and tri-chlorophenols (CPs) were studied using trioctylphosphine oxide (TOPO)- and trioctylmethylammonium chloride (TOMAC)-impregnated membrane disks (Empore^TM). The solid-phase extraction of CPs at a pH lower than 7 was markedly enhanced with TOPO, and became almost quantitative. This extraction enhancement is ascribed to hydrogen bonding between TOPO and CPs in the solid phase. The extraction of CPs under the basic conditions was markedly enhanced with TOMAC. A quantitative recovery of CPs at pH 2.9∼10.3 was achieved using both TOPO and TOMAC-impregnated membrane disks. To determine CPs by HPLC, they were eluted by acetonitrile containing NH₃, evaporated to dryness in the presence of LiOH, and dissolved in a small volume of acetic acid. Trace CPs at 0.1 μg l⁻¹ levels were readily concentrated by a factor of 500 and quantitatively recovered.