Dispersive liquid–liquid microextraction for determina.pdfVIP

chemija. 2009. vol. 20. No. 3. P. 175–179 ? lietuvos moksl? akademija, 2009 ? lietuvos moksl? akademijos leidykla, 2009 Dispersive liquid–liquid microextraction for determina- tion of volatile aromatic hydrocarbons in water Edita Pusva?kien?, Aliona Jurkina, Vida Vi?ka?kait?* Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania * corresponding author. e-mail: vida.vickackaite@chf.vu.lt Dispersive liquid–liquid microextraction is suggested for volatile aromatic hydrocarbon sampling and preconcentration. The effects of extraction solvent type, extraction and dis- perser solvent volume, extraction time and ionic strength of the solution were investigated. Carbon tetrachloride containing n-octane as the internal standard was used as an extract- ing solvent, and acetone was used as a disperser solvent. The calibration graphs were lin- ear up to 2 mg ml–1, the correlation coefficients were 0.998–0.999, the enrichment factors were from 144 for toluene to 239 for o-xylene, and the detection limits were 0.40, 0.35 and 0.33 μg l–1 for toluene, ethylbenzene and o-xylene, respectively. Repeatabilities of the results were acceptable, with relative standard deviations up to 11.7%. A possibility to apply the proposed method for volatile aromatic hydrocarbon determination in water samples was demonstrated. Key words: dispersive liquid–liquid microextraction, gas chromatography, volatile aro- matic hydrocarbons, water samples IntroductIon Volatile aromatic hydrocarbons are widely spread in the environment. Benzene, toluene, ethylbenzene and xylenes (BTEX) are used as solvents and precursors for many plas- tics, are found in oil and oil products and released into the environment from petroleum refining industries [1]. BTEX seriously affect human health. Short-term effects include headache, fatigue, nervous system disorders, immune sys- tem depression, anemia; long-term effects are chromosome aberrat