Volatile Compounds in Human Breath

Like all living organism humans exchange VOC with the environment. Respiration, as the primary exchange route, does not only supply oxygen and remove carbon dioxide, but breath also carries compounds at trace level that carry information on e.g. metabolism, absorbed substances and microbial population of the respiratory ducts. Its analysis can therefore give inside about pathogenic processes and events.

G.A.S. offers analytical devices for the analysis of volatile compounds at trace levels. Due to the outstanding sensitivity of the ion-mobility-spectrometry used as detector breath can directly be sampled without the need for any pre-concentration. Equipped with a gas chromatographic pre-separation volatile compounds can separately be quantified within one single measurement [1].

The BreathSpec® operates on a stand-alone base and allows a direct exhaling into the device. The sampling is highly reproducible as it is controlled by an integrated spirometer with embedded sensors based on a CO2 and flow measurement. Due to an integrated pneumatic system (heated gas ways, electrical six-port valve and integrated pump) samples are introduced directly in a controlled manner according to the measurement/operation requirements. G.A.S. furthermore developed a low-cost set-up to sample breath in standard disposable syringes. The breath then can be analyzed using the GC-IMS equipped with a Luer-adaptor. This is the most flexible way of sampling since the configuration accepts gaseous samples from any source and can actively sample in static- and dynamic gas spaces. Therefore it is possible to investigate the gas phase in e.g. nose- or mouth- cavities or even from the skin. Since the Luer tip is a standard adaptor used in a wide range of medical equipment sampling can be done on e.g. intubated patients.

Both devices and sampling methods are designed to be non-invasive and non-aggravating to the proband. For sampling only one breath cycle is sufficient. Typical runtimes of the analysis are 10 minutes. Examples for detectable compounds in healthy human breath are isoprene, short chained alcohols, aldehydes and ketones, acetonitril, nitric oxide*, dimethylsulfide, further sulphur-compounds*.* Analysis in negative polarization mode of the IMS

[1] Ruzsanyi, V.; Baumbach, J.I.; Sielemann, S.; Litterst, P.; Westhoff, M.; Freitag, L.: Detection of human metabolites using multi-capillary columns coupled to ion mobility spectrometers, J. Chromatographia A 1084 (1-2) (2005) 145-151