title: Dispersive liquid-liquid microextraction method based on solidification of floating organic drop for extraction of organochlorine pesticides in water samples.
abstract: A new simple and rapid dispersive liquid-liquid microextraction method has been developed for the extraction and analysis of organochlorine pesticides (OCPs) in water samples. The method is based on the solidification of a floating organic drop (DLLME-SFO) and is combined with gas chromatography/electron capture detection (GC/ECD). Very little solvent is required in this method. The disperser solvent (200microL acetonitrile) containing 10microL hexadecane (HEX) is rapidly injected by a syringe into the 5.0mL water sample. After centrifugation, the fine HEX droplets (6+/-0.5microL) float at the top of the screw-cap test tube. The test tube is then cooled in an ice bath. After 5min, the HEX solvent solidifies and is then transferred into a conical vial, where it melts quickly at room temperature, and 1microL of it is injected into a gas chromatograph for analysis. Under optimum conditions, the enrichment factors and extraction recoveries are high and range between 37-872 and 82.9-102.5%, respectively. The linear range is wide (0.025-20microgL(-1)), and the limits of detection are between 0.011 and 0.11microgL(-1) for most of the analytes. The relative standard deviation (RSD) for 1microgL(-1) of OCPs in water was in the range of 5.8-8.8%. The performance of the method was gauged by analyzing samples of lake and tap water.
authors.affiliation: Department of Chemistry, National Tsing Hua University, 101, Sec. 2, Kung Fu Rd., Hsinchu 30013, Taiwan.
authors.forename: Mei-I
authors.initials: MI
authors.lastname: Leong
authors.forename: Shang-Da
authors.initials: SD
authors.lastname: Huang
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000097:Acetonitriles; D000473:Alkanes; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical; C007932:n-hexadecane; C032159:acetonitrile