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ABSTRACT: Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 12/2012; 911C:84-92. · 2.78 Impact Factor
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ABSTRACT: Volatile organic compounds (VOCs) released or taken up by Streptococcus pneumoniae and Haemophilus influenzae cultures were analyzed by means of gas chromatography mass spectrometry (GC-MS) after adsorption of headspace samples on multibed sorption tubes. Sampling was performed at different time points during cultivation of bacteria to follow the dynamics of VOC metabolism. VOCs were identified not only by spectral library match, but also based on retention times of native standards.. As many as 34 volatile metabolites were released from Streptococcus pneumoniae and 28 from Haemophilus influenzae, comprising alcohols, aldehydes, esters, hydrocarbons, ketones and sulphur containing compounds. For both species, acetic acid, acetaldehyde, methyl methacrylate, 2,3-butanedione and methanethiol were found in strongly, 1-butanol and butanal in moderately elevated concentrations. In addition, characteristic volatile biomarkers were detected for both bacterial species and exclusively for S. pneumoniae also catabolism of aldehydes (3-methylbutanal and hexanal) was found. The results obtained provide important input into the knowledge about volatile bacterial biomarkers, which may become particularly important for detection of pathogens in upper airways by breath-gas analysis in the future.
Microbiology 10/2012; · 3.06 Impact Factor
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ABSTRACT: The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP) is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy). Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non- invasive diagnosis of ventilator associated pneumonia (VAP). For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs).
Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS). As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal), which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid), ketones (e.g. acetoin, 2-nonanone), hydrocarbons (e.g. 2-butene, 1,10-undecadiene), alcohols (e.g. 2-methyl-1-propanol, 2-butanol), esters (e.g. ethyl formate, methyl 2-methylbutyrate), volatile sulfur compounds (VSCs, e.g. dimethylsulfide) and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole).Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ~8*106 [CFUs/ml].
The results obtained provide strong evidence that the detection and perhaps even identification of bacteria could be achieved by determination of characteristic volatile metabolites, supporting the clinical use of breath-gas analysis as non-invasive method for early detection of bacterial lung infections.
BMC Microbiology 06/2012; 12:113. · 3.04 Impact Factor
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ABSTRACT: The approach for breath-VOCs' collection and preconcentration by applying needle traps was developed and optimized. The alveolar air was collected from only a few exhalations under visual control of expired CO(2) into a large gas-tight glass syringe and then warmed up to 45 °C for a short time to avoid condensation. Subsequently, a specially constructed sampling device equipped with Bronkhorst® electronic flow controllers was used for automated adsorption. This sampling device allows time-saving collection of expired/inspired air in parallel onto three different needle traps as well as improvement of sensitivity and reproducibility of NT-GC-MS analysis by collection of relatively large (up to 150 ml) volume of exhaled breath. It was shown that the collection of alveolar air derived from only a few exhalations into a large syringe followed by automated adsorption on needle traps yields better results than manual sorption by up/down cycles with a 1 ml syringe, mostly due to avoided condensation and electronically controlled stable sample flow rate. The optimal profile and composition of needle traps consists of 2 cm Carbopack X and 1 cm Carboxen 1000, allowing highly efficient VOCs' enrichment, while injection by a fast expansive flow technique requires no modifications in instrumentation and fully automated GC-MS analysis can be performed with a commercially available autosampler. This optimized analytical procedure considerably facilitates the collection and enrichment of alveolar air, and is therefore suitable for application at the bedside of critically ill patients in an intensive care unit. Due to its simplicity it can replace the time-consuming sampling of sufficient breath volume by numerous up/down cycles with a 1 ml syringe.
Journal of Breath Research 06/2012; 6(2):027107. · 2.54 Impact Factor
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ABSTRACT: The scent profile of human urine was investigated as potential source of chemical markers of human presence in collapsed buildings after natural or man-made disasters.
The main goals of this study were to build a library of potential biomarkers of human urine to be used for the detection of entrapped victims and to further examine their evolution profile in time.
Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect and identify the volatile organic compounds (VOCs) spontaneously released from urine of 20 healthy volunteers. Additionally, the evolution of human urine headspace during four days storage at room temperature was investigated.
33 omnipresent species with incidence higher than 80% were selected as potential urine markers. The most represented chemical classes were ketones with 10 representatives, aldehydes (7 species) and sulfur compounds (7 species). The monitoring of the evolution of the urine scent demonstrated an increase in the emission of 26 omnipresent urinary volatiles (rise from 36% to 526%). The highest increase was noted for dimethyldisulfide and dimethyltrisulfide (fivefold increase) and 3-methyl-2-butanone, 4-methyl-2-pentanone and 3-hexanone (fourfold rise). Only three compounds exhibited decreasing trend; dimethylsulfone, octanal and propanal.
The ubiquitous urine VOCs identified within this study create a library of potential markers of human urine to be verified in further field studies, involving portable and sensitive instruments, directly applied in the field.
Toxicology mechanisms and methods 04/2012; 22(7):502-11. · 1.03 Impact Factor
