Determination of chlorophenols in water samples using simultaneous dispersive liquid–liquid microextraction and derivatization followed by gas chromatography-electron-capture detection

Abstract

Simultaneous dispersive liquid–liquid microextraction (DLLME) and derivatization combined with gas chromatography-electron-capture detection (GC-ECD) was used to determine chlorophenols (CPs) in water sample. In this derivatization/extraction method, 500 μL acetone (disperser solvent) containing 10.0 μL chlorobenzene (extraction solvent) and 50 μL acetic anhydride (derivatization reagent) was rapidly injected by syringe in 5.00 mL aqueous sample containing CPs (analytes) and K 2CO 3 (0.5%, w/v). Within a few seconds the analytes derivatized and extracted at the same time. After centrifugation, 0.50 μL of sedimented phase containing enriched analytes was determined by GC-ECD. Some effective parameters on derivatization and extraction, such as extraction and disperser solvent type and their volume, amount of derivatization reagent, derivatization and extraction time, salt addition and amount of K 2CO 3 were studied and optimized. Under the optimum conditions, enrichment factors and recoveries are in the range of 287–906 and 28.7–90.6%, respectively. The calibration graphs are linear in the range of 0.02–400 μg L −1 and limit of detections (LODs) are in the range of 0.010–2.0 μg L −1. The relative standard deviations (RSDs, for 200 μg L −1 of MCPs, 100 μg L −1 of DCPs, 4.00 μg L −1 of TCPs, 2.00 μg L −1 of TeCPs and PCP in water) with and without using internal standard are in the range of 0.6–4.7% ( n = 7) and 1.7–7.1% ( n = 7), respectively. The relative recoveries of well, tap and river water samples which have been spiked with different levels of CPs are 91.6–104.7, 80.8–117.9 and 83.3–101.3%, respectively. The obtained results show that simultaneous DLLME and derivatization combined with GC-ECD is a fast simple method for the determination of CPs in water samples.