QSRR Models for Kováts’ Retention Indices of a Variety of Volatile Organic Compounds on Polar and Apolar GC Stationary Phases Using Molecular Connectivity Indexes

Abstract Bacteria emits a multitude of volatile organic compounds (VOCs) into the headspace as a mean of interactions with the environments, as well as intra- and interkingdom communication for survival and persistence in the nature and within their hosts. Campylobacter, which is often found in poultry and ruminants, has shown great persistence in aquatic environments, making it one of the world's most dangerous foodborne pathogens, killing thousands of people annually. In this study, the VOCs emitted by both thermophilic (C. jejuni, C. coli and C. lari) and non-thermophilic Campylobacter (C. fetus) of clinical concerns, impacted by nutrients composition (media) and growth phase were identified. Most thermophilic Campylobacter were shown to release volatile alcohols and ketones (1s,4R,7R,11R-1,3,4,7-Tetramethyltricyclo [5.3.1.0(4,11)] undec-2-en-8-one and Isophorone) during early stationary and stationary phases using active sampling with active charcoal adsorbent and GC-MS analysis. C. jejuni cultured in the Brain Heart Infusion had 1-Heptadecanol in its headspace gas, but not in Bolton Broth. The non-thermophilic C. fetus did not produce alcohols or ketones, but rather a variety of unidentified chemicals that will require further investigation in the future. Overall, PCA analysis revealed that the five Campylobacter strains studied created distinct volatilomes, allowing for future Campylobacter identification based on VOCs.

Download Full-text

Comprehensive two-dimensional gas chromatography (GC×GC) measurements of volatile organic compounds in the atmosphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-3-1139-2003 ◽

2003 ◽

Vol 3 (1) ◽

pp. 1139-1181 ◽

Cited By ~ 5

Author(s):

X. Xu ◽

L. L. P. van Stee ◽

J. Williams ◽

J. Beens ◽

M. Adahchour ◽

...

Keyword(s):

Gas Chromatography ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Retention Indices ◽

Two Dimensional ◽

Ground Station ◽

Flame Ionization ◽

Peak Identification ◽

Volatile Organic

Abstract. During the MINOS campaign in August 2001 comprehensive two-dimensional gas chromatography (GC×GC) was applied to the in situ measurements of atmospheric volatile organic compounds (VOCs) at the Finokalia ground station, Crete. The measurement system employs a thermal desorption unit for on-line sampling and injection, and a GCxGC separation system equipped with a flame ionization detector (FID) for detection. The system was optimized to resolve C7−C14 organic components. Two-dimensional chromatograms from measurements of Finokalia air samples show several hundred well-separated peaks. To facilitate peak identification, cartridge samples collected at Finokalia were analyzed using the same GC×GC system coupled with a time-of-flight mass spectrometer (TOF-MS). The resulting mass spectra were deconvoluted and compared to spectra from a database for tentative peak identification. About 650 peaks have been identified in the two-dimensional plane, with significant signal/noise ratios (>100) and high spectra similarities (>800). By comparing observed retention indices with those found in the literature, 235 of the identifications have been confirmed. 150 of the confirmed compounds show up in the C7−C14 range of the chromatogram from the in situ measurement. However, at least as many peaks remain unidentified. For quantification of the GCxGC measurements, peak volumes of measured compounds have been integrated and externally calibrated using a standard gas mixture.

Download Full-text

Comprehensive two-dimensional gas chromatography (GC × GC) measurements of volatile organic compounds in the atmosphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-3-665-2003 ◽

2003 ◽

Vol 3 (3) ◽

pp. 665-682 ◽

Cited By ~ 84

Author(s):

X. Xu ◽

L. L. P. Stee ◽

J Williams ◽

J. Beens ◽

M. Adahchour ◽

...

Keyword(s):

Gas Chromatography ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Retention Indices ◽

Two Dimensional ◽

Ground Station ◽

Peak Identification ◽

Volatile Organic ◽

Gc X Gc

Abstract. During the MINOS campaign in August 2001 comprehensive two-dimensional gas chromatography (GC x GC) was applied to the in situ measurements of atmospheric volatile organic compounds (VOCs) at the Finokalia ground station, Crete. The measurement system employs a thermal desorption unit for on-line sampling and injection, and a GC x GC separation system equipped with a flame ionization detector (FID) for detection. The system was optimized to resolve C7-C14 organic components. Two-dimensional chromatograms from measurements of Finokalia air samples show several hundred well-separated peaks. To facilitate peak identification, cartridge samples collected at Finokalia were analyzed using the same GC x GC system coupled with a time-of-flight mass spectrometer (TOF-MS). The resulting mass spectra were deconvoluted and compared to spectra from a database for tentative peak identification. About 650 peaks have been identified in the two-dimensional plane, with significant signal/noise ratios (>100) and high spectra similarities (>800). By comparing observed retention indices with those found in the literature, 235 of the identifications have been confirmed. 150 of the confirmed compounds show up in the C7-C14 range of the chromatogram from the in situ measurement. However, at least as many peaks remain unidentified. For quantification of the GC x GC measurements, peak volumes of measured compounds have been integrated and externally calibrated using a standard gas mixture.

Download Full-text