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Multidimensional Gas Chromatography (multidimensional + gas_chromatography)
Selected AbstractsChiral Multidimensional Gas Chromatography (MDGC) and Chiral GC,Olfactometry with a Double-Cool-Strand Interface: Application to MalodorsCHEMISTRY & BIODIVERSITY, Issue 2 2006Frédéric Begnaud Abstract Volatile sulfur compounds such as 3-methyl-3-sulfanylhexan-1-ol (1) are largely responsible for axillary-sweat malodors. In this work, we describe the determination of the enantiomer ratio of the trace constituent 1 and the odor description of its antipodes (R)- and (S)- 1 by means of multidimensional gas chromatography (MDGC) in combination with chiral gas chromatography,olfactometry (GC-O). This technique allowed the on-line evaluation of the sensory character of both enantiomers via a sniffing port, and is based on a novel double-cool-strand interface (DCSI). First, the system's inertness was tested towards the labile compound 2-methylfuran-3-thiol (MFT; 2). Then, the DCSI was used in a new configuration to achieve olfactive characterization by means of chiral GC-O. In contrast to direct smelling after the chiral column, our technique allows, for the first time, to significantly delay the perception of the second-eluting enantiomer after the first one. This lowers the risk of sensory saturation, as the panelist can recover from the first stimulus, before evaluating the second one. To help programming the DCSI, a dedicated program was set up. The enantiomer ratio of the sweat malodor 1 was determined as (S)/(R) 3,:,1, and the dominating (S)-isomer was shown to largely impart its specific character to the overall odor of the sweat extract. [source] Detectability enhancement of spectrophotometric detectors by the use of multidimensional gas chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2002Juan Carlos Medina Abstract Multidimensional gas chromatography (2D GC) is demonstrated as a way to improve limits of detectability of spectrophotometric detectors. UV and IR detectors are generally less sensitive than mass spectrometers or other GC detectors. This has placed some limitations on the useful capabilities provided by spectrophotometric detectors, such as the ability to provide structure-related information for a particular analyte. In this paper, we report results from interfacing a 2D GC instrument to a UV detector. Symmetry factor and the ratio of retention time divided by peak width did not show deterioration of the quality of chromatography when a megabore column was used with this detector. Furthermore, an increase in the limits of detectability over that attainable in a single-column system was realized by using the 2D GC system. However, the low flow (1 mL/min) imposed by the use of a microbore column (250 ,m ID) caused significant tailing when the UV detector was used. [source] Application of comprehensive multidimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOFMS) for high resolution analysis of hop essential oilJOURNAL OF SEPARATION SCIENCE, JSS, Issue 5-6 2004Mark T. Roberts Abstract The selection and quality of hops is a major determinant in beer flavour. Brewers acknowledge that distinctive characteristics of different hop varieties can be traced to the composition of their essential oils. The difficulty in characterising complex mixtures such as hop oil using 1-D chromatography is that many compounds co-elute. With the introduction of comprehensive multidimensional capillary gas chromatography (GC×GC), there is a tremendous improvement in the separation power or peak capacity. Recent work using GC×GC with flame ionisation detection has suggested that there may be over 1,000 compounds in hop oil. This work describes the use of GC×GC combined with TOFMS detection (Leco Pegasus 4D instrument) to analyse Target hop oil. The TOFMS spectral acquisition rate of 60 Hz provided sufficient spectra per peak (2-D peak base width of 0.1,0.2 s) for identification (119 components were identified with 45 previously unreported compounds). When analysing results, an advantage of GC×GC coupled to TOFMS is that 2-D chromatograms can be viewed for individual masses that are characteristic of particular functional groups. This allows the analyst to view the various homologous series of compounds although in certain cases coelution may still be present as shown by the esters with mass 75. [source] Detectability enhancement of spectrophotometric detectors by the use of multidimensional gas chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2002Juan Carlos Medina Abstract Multidimensional gas chromatography (2D GC) is demonstrated as a way to improve limits of detectability of spectrophotometric detectors. UV and IR detectors are generally less sensitive than mass spectrometers or other GC detectors. This has placed some limitations on the useful capabilities provided by spectrophotometric detectors, such as the ability to provide structure-related information for a particular analyte. In this paper, we report results from interfacing a 2D GC instrument to a UV detector. Symmetry factor and the ratio of retention time divided by peak width did not show deterioration of the quality of chromatography when a megabore column was used with this detector. Furthermore, an increase in the limits of detectability over that attainable in a single-column system was realized by using the 2D GC system. However, the low flow (1 mL/min) imposed by the use of a microbore column (250 ,m ID) caused significant tailing when the UV detector was used. [source] Chiral Multidimensional Gas Chromatography (MDGC) and Chiral GC,Olfactometry with a Double-Cool-Strand Interface: Application to MalodorsCHEMISTRY & BIODIVERSITY, Issue 2 2006Frédéric Begnaud Abstract Volatile sulfur compounds such as 3-methyl-3-sulfanylhexan-1-ol (1) are largely responsible for axillary-sweat malodors. In this work, we describe the determination of the enantiomer ratio of the trace constituent 1 and the odor description of its antipodes (R)- and (S)- 1 by means of multidimensional gas chromatography (MDGC) in combination with chiral gas chromatography,olfactometry (GC-O). This technique allowed the on-line evaluation of the sensory character of both enantiomers via a sniffing port, and is based on a novel double-cool-strand interface (DCSI). First, the system's inertness was tested towards the labile compound 2-methylfuran-3-thiol (MFT; 2). Then, the DCSI was used in a new configuration to achieve olfactive characterization by means of chiral GC-O. In contrast to direct smelling after the chiral column, our technique allows, for the first time, to significantly delay the perception of the second-eluting enantiomer after the first one. This lowers the risk of sensory saturation, as the panelist can recover from the first stimulus, before evaluating the second one. To help programming the DCSI, a dedicated program was set up. The enantiomer ratio of the sweat malodor 1 was determined as (S)/(R) 3,:,1, and the dominating (S)-isomer was shown to largely impart its specific character to the overall odor of the sweat extract. [source] | ||||||||||