Solid-phase extraction combined with dispersive liquid-liquid microextraction-ultra preconcentration of chlorophenols in aqueous samples

The solid-phase extraction (SPE) joined with the dispersive liquid-liquid microextraction (DLLME) has been developed as an ultra preconcentration technique for the determination of chlorophenols in water samples. Chlorophenols (CPs) were employed as model compounds to assess the extraction procedure and were determined by gas chromatography-electron-capture detection (GC-ECD). In solid-phase extraction-dispersive liquid-liquid microextraction (SPE-DLLME), CPs were adsorbed from a large volume of aqueous samples (100 mL) into 100 mg functionalized styrene-divinylbenzene polymer (PPL) sorbent. After the elution of the desired compounds from the sorbent by using acetone, DLLME technique was performed on the obtained solution. Some important extraction parameters, such as sample solution flow rate, breakthrough volume, sample pH, type and volume of the elution solvent as well as the salt addition, were studied and optimized. The new method (SPE-DLLME) provided an ultra enrichment factor (4390-17,870) for 19 CPs. The calibration graphs were linear in the range of 0.00 1-20 mu g L-1 and the limits of detection (LODs) ranged from 0.0005 to 0.1 mu g L-1. The relative standard deviations (RSDs, for 10.0 mu g L-1 of MCPs, 5.00 mu g L-1 of DCPs, 0.200 mu g L-1 of TCPs, 0.100 Rg L-1 of TeCPs and PCP) with and without the internal standard varied from 1.1 to 6.4% (n = 7) and 2.5-9.7% (n = 7), respectively. The relative recoveries of the well, tap and river water samples, spiked with different levels of CPs, were 71-110%, 73-115% and 88-121%, respectively. (c) 2007 Elsevier B.V. All rights reserved.