title: Measurement of PCDDs, PCDFs, and non-ortho-PCBs by comprehensive two-dimensional gas chromatography-isotope dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS).
abstract: Comprehensive two-dimensional gas chromatography with isotope-dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS) was used to measure polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and coplanar polychlorinated biphenyl (cPCB) concentrations in ash, sediment, vegetation, and fish samples. The GC x GC capability was achieved by using a quad jet, dual stage, thermal modulator. Zone compression of the GC peaks from modulation resulted in a significant increase of the signal intensity over classical GC-IDTOFMS. The GC x GC column set used an Rtx-Dioxin 2 phase as the first dimension ((1)D ) and an Rtx-500 as the second dimension ((2)D ). The chromatographic separation of the 17 PCDD/Fs and the 4 cPCBs was attained in (1)D except for 2,3,7,8-TCDD and CB126 for which deconvoluted ion currents (DIC) were required to be reported separately. The Rtx-500 phase separated the bulk matrix interfering compounds from the target analytes in (2)D . The instrumental limit of detection (iLODs) was 0.5pg for 2,3,7,8-TCDD. The calibration curves showed good correlation coefficients for all the compounds investigated in the concentration range of 0.5-200pg. GC x GC-IDTOFMS results compared favorably to those from conventional isotope-dilution one-dimensional gas chromatography-high resolution mass spectrometry (GC-IDHRMS). The comprehensive mass analysis of the TOFMS further permitted the identification of other contaminants of concern in the samples.
authors.affiliation: Centers for Disease Control and Prevention (CDC), National Center for Environmental Health (NCEH), Division of Laboratory Sciences (DLS), Organic Analytical Toxicology (OAT) Branch, 4770 Buford Hwy NE, Mail Stop F-17, Atlanta, GA 30341, USA.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Focant
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Reiner
authors.forename: Karen
authors.initials: K
authors.lastname: Macpherson
authors.forename: Terry
authors.initials: T
authors.lastname: Kolic
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjödin
authors.forename: Donald G
authors.initials: DG
authors.lastname: Patterson
authors.forename: Shawn L
authors.initials: SL
authors.lastname: Reese
authors.forename: Frank L
authors.initials: FL
authors.lastname: Dorman
authors.forename: Jack
authors.initials: J
authors.lastname: Cochran