Experimental setup and analytical methods for the non-invasive determination of volatile organic compounds, formaldehyde and NOx in exhaled human breath.
Different analytical devices were tested and evaluated for their suitability of breath gas analysis by examining the physiological parameters and chemical substances in the exhaled breath of ten healthy probands during light cycling in dependence of methanol-rich nutrition. The probands exercised under normal breathing conditions on a bicycle ergometer. Breath air was exhaled into a glass cylinder and collected under steady-state conditions. Non-invasively measured parameters were pulse rate, breath frequency, temperature, relative humidity, NO(x), total volatile organic compounds (TVOC(PAS)), carbon dioxide (CO(2)), formaldehyde, methanol, acetaldehyde, acetone, isoprene and volatile organic compounds (VOCs). Methanol rich food and beverages strongly influenced the concentration of methanol and other organic substances in human breath. On the other hand, nutrition and smoking had no clear effect on the physical conditions of the probands. The proton transfer reaction mass spectrometry (PTR-MS) method was found to be very suitable for the analysis of breath gas but the m/z 31, if assigned to formaldehyde, is sensitive to interferences. The time vs. concentration curves of nitric oxide showed sudden peaks up to 120ppb in most of the measurements. In one case a strong interference of the NO(x) signal was observed. The time resolved analysis of exhaled breath gas is of high capability and significance for different applications if reliable analytical techniques are used. Some compounds like nitric oxide (NO), methanol, different VOCs as well as sum parameters like TVOC(PAS) are especially suitable as markers. Formaldehyde, which is rapidly metabolized in the human body, could be measured reliably as a trace component by the acetylacetone (acac) method but not by PTR-MS.
Hannover Medical School, Sports Physiology and Sports Medicine, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
Ulrich
U
Riess
Uwe
U
Tegtbur
Christian
C
Fauck
Frank
F
Fuhrmann
Doreen
D
Markewitz
Tunga
T
Salthammer
D000079:Acetaldehyde / Q000032:analysis; D000096:Acetone / Q000032:analysis; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods*; D002070:Butadienes / Q000032:analysis; D005557:Formaldehyde / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D045782:Hemiterpenes / Q000032:analysis; D006801:Humans; D013058:Mass Spectrometry; D000432:Methanol / Q000032:analysis; D009589:Nitrogen Oxides / Q000032:analysis*; D010420:Pentanes / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis*
D002070:Butadienes; D045782:Hemiterpenes; D009589:Nitrogen Oxides; D010420:Pentanes; D055549:Volatile Organic Compounds; C005059:isoprene; D000096:Acetone; D005557:Formaldehyde; D000079:Acetaldehyde; D000432:Methanol