title: Headspace in-tube microextraction coupled with micellar electrokinetic chromatography of neutral aromatic compounds.
abstract: Headspace (HS) extraction can be carried out easily and aptly via single drop microextraction coupled with capillary electrophoresis (CE). However, one drawback is the difficulty of keeping the single drop stably at the capillary tip. To solve this problem, we have recently demonstrated HS in-tube microextraction (ITME) of acidic compounds such as chlrophenols in an acidic sample using a basic run buffer plug in the separation capillary for CE as an acceptor phase. In this report, an organic acceptor plug in a capillary was used to extract neutral organic volatile pollutants such as BTEX (benzene, toluene, ethylbenzene, and m-xylene). After extraction, the analytes enriched in the organic acceptor plug were analyzed with micellar electrokinetic chromatography (MEKC). The enrichment factors for BTEX in a standard solution were up to 350 under an optimal condition of 25°C for 20 min. As an application, BTEX spiked into bottled water were analyzed with HS-ITME-MEKC, and the enrichment factors for BTEX were up to 320. The limits of detections were 1-4 ppb, which are at least 200 times lower than the US Environmental Protection Agency guidelines for drinking water, except benzene. The entire procedure of HS-ITME-MEKC was carried out automatically using a commercial CE instrument.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-747, Republic of Korea.
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Cho
authors.affiliation: Seoul Science High School, Seoul 110-530, Republic of Korea.
authors.forename: Bum Su
authors.initials: BS
authors.lastname: Park
authors.affiliation: Seoul Science High School, Seoul 110-530, Republic of Korea.
authors.forename: Woo Sung
authors.initials: WS
authors.lastname: Jung
authors.affiliation: Seoul Science High School, Seoul 110-530, Republic of Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Seoul Science High School, Seoul 110-530, Republic of Korea.
authors.forename: Yunhwan
authors.initials: Y
authors.lastname: Jung
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-747, Republic of Korea. Electronic address: dschung@snu.ac.kr.
authors.forename: Doo Soo
authors.initials: DS
authors.lastname: Chung
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D006841:Hydrocarbons, Aromatic
keywords: BTEX; Capillary electrophoresis; Headspace extraction; In-tube microextraction