High performance liquid chromatography determination of chlorophenols in water samples after preconcentration by continuous flow liquid membrane extraction on-line coupled with a precolumn

A continuous flow liquid membrane extraction (CFLME)-C-18 precolumn-liquid chromatography system was developed for preconcentration and determination of chlorinated phenols (CPs). After preconcentration by CFLME, which is based on the combination of continuous flow liquid-liquid extraction and supported liquid membrane, CPs were enriched in 960 mul of 0.5 mol 1(-1) NaOH used as acceptor. This acceptor was on-line neutralized and transported onto the C-18 precolumn where analytes were absorbed and focused. Then the focused analytes were injected onto the C-18 analytical column for separation and detected at 215 nm with a diode array detector. CFLME related parameters such as flow rates, pH of donor and acceptor concentration were optimized. The proposed method presents detection limits of 0.02-0.09 mug 1(-1) (S/N = 3) when 100 ml samples were enriched. The proposed method was successfully applied to determine CPs in tap water and river water samples with spiked recoveries in the range of 70-121%. (C) 2003 Elsevier Science B.V. All rights reserved.