title: Determination of phenylurea herbicides in aqueous samples using partitioned dispersive liquid-liquid microextraction.
abstract: Partitioned dispersive liquid-liquid microextraction (PDLLME), using THF as the dispersive solvent and dichloromethane as the extraction solvent, was utilized to isolate and concentrate phenylurea herbicides (PUHs) from aqueous samples. In PDLLME, a dispersive solvent should be able to partition in the organic extractant droplets to effectively extract the polar organic compounds from aqueous samples. The mixture of the water-immiscible extractant and the partitioned dispersive solvent was obtained by centrifugation, dried under low pressure, reconstituted in methanol-water mixture (1:1), and injected into a HPLC system for the determination of PUHs. The enrichment factors of the PUHs ranged from 68 to 126 under the optimal conditions. The linear range was 0.5-100 ng ml(-1) for each analyte, the relative standard deviations of PUHs were in the range of 1.5-5.9% (n=5), and the detection limits (signal-to-noise ratio of 3) ranged from 0.10 to 0.28 ng ml(-1) for the herbicides. The range of intraday precision (n=5) for PUHs at the levels of 0.5, 5, and 50 ng ml(-1) were 3.0-5.9%, 1.8-3.3%, and 2.2-3.6%, respectively. The range of interday precision (n=5) at 0.5, 5, and 50 ng ml(-1) were 0.4-1.8%, 1.2-2.4%, and 0.9-2.3%, respectively. The recoveries of PUHs from three spiked river water samples, at a level of 10 ng ml(-1), were 91.2-104.1%. Due to its rapidity, ease of operation, and high recovery, PDLLME can be utilized to isolate and concentrate organic environmental contaminants such as PUHs from aqueous samples.
authors.affiliation: Department of Chemistry, Soochow University, Shihlin, Taipei, Taiwan.
authors.forename: Tso-Ying
authors.initials: TY
authors.lastname: Chou
authors.forename: Shu-Ling
authors.initials: SL
authors.lastname: Lin
authors.forename: Ming-Ren
authors.initials: MR
authors.lastname: Fuh
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry; D006540:Herbicides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D008044:Linuron / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry; D015394:Molecular Structure; D010671:Phenylurea Compounds / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D013056:Spectrophotometry, Ultraviolet; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry
chemical_list: D006540:Herbicides; D010671:Phenylurea Compounds; D014874:Water Pollutants, Chemical; D008044:Linuron; C030651:monolinuron