title: Reverse micelle-mediated dispersive liquid-liquid microextraction of 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid.
abstract: A supramolecular solvent consisting of reverse micelles of decanoic acid, dispersed in a continuous phase of tetrahydrofuran:water, was proposed as an efficient microextraction technique for extraction of selected chlorophenoxy acid herbicides from water samples prior to high-performance liquid chromatography UV determination. The disperser solvent (1.0 mL tetrahydrofuran) containing 20 mg decanoic acid was rapidly injected into 10.0 mL of water sample. After centrifugation, the reverse micelle-rich phase (25 ± 0.5 μL) was floated at top of the home-designed centrifuge tube. The solvent was collected and 20 μL of it was injected into high-performance liquid chromatography for analysis. The results showed that the in situ solvent formation and extraction process can be completed in a few seconds. Under the optimal conditions, limits of detection of the method for 4-chloro-2-methylphenoxyacetic acid and 2,4-dichlorophenoxyacetic acid were in the range of 0.5-0.8 μg L(-1)  and the repeatability of the proposed method, expressed as relative standard deviation, varied in the range of 2.5-3.2%. Linearity was found to be in the range of 1-200 μg L(-1)  and the preconcentration factors were between 148 and 157. The mean percentage recoveries exceeded 92.0% for all the spiking levels in real water samples.
authors: Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, Tehran, Iran.
authors: Moslem
authors: M
authors: Tayyebi
authors: Yadollah
authors: Y
authors: Yamini
authors: Morteza
authors: M
authors: Moradi
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003652:Decanoic Acids / Q000737:chemistry; D059627:Liquid Phase Microextraction; D008823:Micelles; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D003652:Decanoic Acids; D008823:Micelles; D014874:Water Pollutants, Chemical; D015084:2,4-Dichlorophenoxyacetic Acid; C031071:decanoic acid; D008456:2-Methyl-4-chlorophenoxyacetic Acid