Determination of volatile organic compounds in exhaled breath of patients with lung cancer using solid phase microextraction and gas chromatography mass spectrometry.
BACKGROUND
Analysis of exhaled breath is a promising diagnostic method. Sampling of exhaled breath is non-invasive and can be performed as often as considered desirable. There are indications that the concentration and presence of certain of volatile compounds in exhaled breath of lung cancer patients is different from concentrations in healthy volunteers. This might lead to a future diagnostic test for lung cancer.


METHODS
Exhaled breath samples from 65 patients with different stages of lung cancer and undergoing different treatment regimes were analysed. Mixed expiratory and indoor air samples were collected. Solid phase microextraction (SPME) with carboxen/polydimethylsiloxane (CAR/PDMS) sorbent was applied. Compounds were analysed by means of gas chromatography (GC) and mass spectrometry (MS).


RESULTS
The method we used allowed identification with the spectral library of 103 compounds showing at least 15% higher concentration in exhaled breath than in inhaled air. Among those 103 compounds, 84 were confirmed by determination of the retention time using standards based on the respective pure compound. Approximately, one third of the compounds detected were hydrocarbons. We found aromatic hydrocarbons, alcohols, aldehydes, ketones, esters, ethers, sulfur compounds, nitrogen-containing compounds and halogenated compounds. Acetonitrile and benzene were two of 10 compounds which correlated with smoking behaviour. A comparison of results from cancer patients with those of 31 healthy volunteers revealed differences in the concentration and presence of certain compounds. The sensitivity for detection of lung cancer patients based on eight different compounds not seen in exhaled breath of healthy volunteers was 51% and the specificity was 100%. These eight potential markers for detection of lung cancer are 1-propanol, 2-butanone, 3-butyn-2-ol, benzaldehyde, 2-methyl-pentane, 3-methyl-pentane, n-pentane and n-hexane.


CONCLUSIONS
SPME is a relatively insensitive method and compounds not observed in exhaled breath may be present at a concentration lower than LOD. The main achievement of the present work is the validated identification of compounds observed in exhaled breath of lung cancer patients. This identification is indispensible for future work on the biochemical sources of these compounds and their metabolic pathways.
Ligor
Magdalena
M
Department of Anaesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
Ligor
Tomasz
T
Bajtarevic
Amel
A
Ager
Clemens
C
Pienz
Martin
M
Klieber
Martin
M
Denz
Hubert
H
Fiegl
Michael
M
Hilbe
Wolfgang
W
Weiss
Wolfgang
W
Lukas
Peter
P
Jamnig
Herbert
H
Hackl
Martin
M
Buszewski
Boguslaw
B
Miekisch
Wolfram
W
Schubert
Jochen
J
Amann
Anton
A
D000328:Adult; D000368:Aged; D001944:Breath Tests; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009930:Organic Chemicals / Q000032:analysis* / Q000737:chemistry; D012015:Reference Standards; D012680:Sensitivity and Specificity; D012907:Smoking; D052617:Solid Phase Microextraction; D014835:Volatilization
D009930:Organic Chemicals