Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Open-vessel focused microwave (FMW) extraction with a purely aqueous carbonate solution was used for the extraction of chlorophenols from various solid matrices. After SPE on C18-bonded silica, the analytes were determined as such by LC-UV or, as their acetyl derivatives, by GC-ECD. The FMW aqueous extraction is efficient and rapid and no organic solvents are used. PCP was detected in several solid samples, with recoveries of 101-115% (RSD, 2-4%) relative to Soxhlet extraction. Similar recoveries were obtained for the other chlorophenols for spiked samples.
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PMID:Focused microwave aqueous extraction of chlorophenols from solid matrices and their analysis by chromatographic techniques. 1583 Sep 55

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 microL acetone (disperser solvent) containing 10.0 microL chlorobenzene (extraction solvent) and 50 microL acetic anhydride (derivatization reagent) was rapidly injected by syringe in 5.00 mL aqueous sample containing CPs (analytes) and K(2)CO(3) (0.5%, w/v). Within a few seconds the analytes derivatized and extracted at the same time. After centrifugation, 0.50 microL 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(2)CO(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 microg L(-1) and limit of detections (LODs) are in the range of 0.010-2.0 microg L(-1). The relative standard deviations (RSDs, for 200 microg L(-1) of MCPs, 100 microg L(-1) of DCPs, 4.00 microg L(-1) of TCPs, 2.00 microg 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.
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PMID:Determination of chlorophenols in water samples using simultaneous dispersive liquid-liquid microextraction and derivatization followed by gas chromatography-electron-capture detection. 1751 36

Chlorophenols (CPs) and polychlorinated biphenyls (PCBs) are two of the most important groups of high-priority pollutants, due to their carcinogenicity, toxicity, and mutagenicity. This paper compares the utilization of two solid-phase microextraction (SPME) based extraction procedures, prior to gas chromatography with electron capture detection (GC-ECD), to determine PCBs (PCB 101 and PCB 153) and CPs (2,4,6-TCP and PCP) in aqueous media. Good linearity was observed with the SPME-GC-ECD method for the concentration range studied; detection limits ranged from 0.5 to 1.0 microg/L. Repeatability was between 13% and 31% for the lowest concentration and between 5.6% and 7.8% for the highest concentration. The uncertainty was determined by Thompson and bottom-up approaches. The identification of the compounds was confirmed by GC-MS. The developed procedure has the advantage of simplicity of sample treatment and avoids the use of potentially hazardous organic solvents and the clean-up or pre-concentration steps. Regarding PCBs, this procedure is simpler and faster, but the limits of detection are higher.
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PMID:Uncertainty measurement of chlorophenols and PCBs analyzed in aqueous media by SPME-GC-ECD. 1922 17