title: Determination of benzene, toluene, ethylbenzene, xylenes in water at sub-ng l-1 levels by solid-phase microextraction coupled to cryo-trap gas chromatography-mass spectrometry.
abstract: A trace analytical method of benzene, toluene, ethylbenzene and xylenes (BTEX) in water has been developed by using headspace solid-phase microextraction (HS-SPME) coupled to cryo-trap gas chromatography-mass spectrometry (GC-MS). The chromatographic peak shape for BTEX was improved by using cryo-trap equipment. The HS-SPME experimental procedures to extract BTEX from water were optimized with a 75 microm carboxen/polydimethylsiloxane (CAR/PDMS)-coated fiber at a sodium chloride concentration of 267 g l(-1), extraction for 15 min at 25 degrees C and desorption at 290 degrees C for 2 min. Good linearity was verified in a range of 0.0001-50 microg l(-1) for each analyte (r(2)=0.996-0.999). The limits of detection (LODs) of BTEX in water reached at sub-ng l(-1) levels. LODs of benzene, toluene, ethylbenzene, m/p-xylene and o-xylene were 0.04, 0.02, 0.05, 0.01 and 0.02 ng l(-1), respectively. The proposed analytical method was successfully used for the quantification of trace BTEX in ground water. The results indicate that HS-SPME coupled to cryo-trap GC-MS is an effective tool for analysis of BTEX in water samples at the sub-ng l(-1) level.
authors.affiliation: Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan, ROC. mrlee@drgon.nchu.edu.tw
authors.forename: Maw-Rong
authors.initials: MR
authors.lastname: Lee
authors.forename: Chia-Min
authors.initials: CM
authors.lastname: Chang
authors.forename: Jianpeng
authors.initials: J
authors.lastname: Dou
mesh_terms: D001554:Benzene / Q000032:analysis*; D001555:Benzene Derivatives / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005615:Freezing; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052617:Solid Phase Microextraction; D014050:Toluene / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014992:Xylenes / Q000032:analysis*
chemical_list: D001555:Benzene Derivatives; D014874:Water Pollutants, Chemical; D014992:Xylenes; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene