Determination of three phthalate esters in environmental samples by coal cinder extraction and cyclodextrin modified
Hongli Sun1, Feng Jiang1, Lin Chen1
1Department of Chemistry and Environmental Engineering, Hubei Key Laboratory of Pollutant Analysis and Reuse Technique, Hubei Normal University, Huangshi, P.R. China.
Abstract:
A new micellar electrokinetic chromatography (MEKC) method using beta-cyclodextrin (ß-CD) as the electrophoresis additive has been developed for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP) and di(2-ethylhexyl) phthalate (DEHP) in environmental samples. To improve the sensitivity of cyclodextrin-modified MEKC (CD-MEKC), a flow injection procedure using a microcolumn packed with coal cinder as the solid-phase extractant was also investigated for the preconcentration and separation of DMP, DEP and DEHP in environmental samples. Parameters affecting CD-MEKC separation and coal cinder flow injection solid-phase extraction were systematically researched. In the presence of the running buffer [5 mmol/L of borax, 5% (v/v) methanol and 25 mmol/L of sodium dodecyl sulfate at pH 9.5], the addition of 14 mmol/L ß-CD greatly improved the separation efficiency. The analytes were quantitatively adsorbed by coal cinders and readily desorbed quantitatively with 0.2 mL of 10% (v/v) methanol-10 mmol/L disodium hydrogen phosphate. Under the optimum conditions, the enrichment factor of coal cinder was 60, and the determination limits of DMP, DEP and DEHP were 3.07, 2.07 and 4.06 ng/mL, respectively. The presented procedure was successfully applied to determine DMP, DEP and DEHP in landfill leachate and water samples with satisfactory results.
