title: Vortex-assisted micro-solid-phase extraction followed by low-density solvent based dispersive liquid-liquid microextraction for the fast and efficient determination of phthalate esters in river water samples.
abstract: A simple and efficient two-step method, vortex-assisted micro-solid-phase extraction (VA-μ-SPE) followed by low-density solvent based dispersive liquid-liquid microextraction (LDS-DLLME) combined with analysis by gas chromatography-mass spectrometry (GC-MS), was developed for the determination of trace level phthalate esters in environmental water samples. The analytes were firstly extracted and preconcentrated by vortex-assisted μ-SPE which was faster than conventional μ-SPE (6min compared to 30min), and then desorbed by ultrasonication into acetonitrile. The latter served as the dispersive solvent in the subsequent LDS-DLLME step which further pre-concentrated the analytes. Six phthalate esters were selected as model compounds for developing and evaluating the method. Some key parameters for VA-μ-SPE and LDS-DLLME, such as sorbent selection and amount, vortex time, ultrasonication solvent and time, extraction solvent type and volume for DLLME, the speed and time of centrifugation, were investigated. Under the most favorable conditions, good limits of detection (as low as 0.006μg/L) and repeatability of extraction (RSDs below 9.2%, n=5) were obtained. The developed method was applied to determine phthalate esters in environmental water samples.
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors: Liang
authors: L
authors: Guo
authors: Hian Kee
authors: HK
authors: Lee
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006586:Hexanes / Q000737:chemistry; D057230:Limit of Detection; D016014:Linear Models; D059627:Liquid Phase Microextraction / Q000379:methods*; D010795:Phthalic Acids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015203:Reproducibility of Results; D045483:Rivers / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D013010:Sonication / Q000379:methods; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D006586:Hexanes; D010795:Phthalic Acids; D014874:Water Pollutants, Chemical; C026385:n-hexane; D012965:Sodium Chloride
keywords: Dispersive liquid–liquid microextraction; Low-density solvent; Phthalate esters; Vortex-assisted micro-solid-phase extraction