Background: Smoking but also inhalation of particulate matter (PM) from air pollution, and some industries induce inflammation
and reactive oxygen species (ROS) production. ROS in turn lead to oxidative stress and increase the risk of respiratory diseases,
including chronic obstructive pulmonary disease (COPD). Compared to invasive blood and broncho-alveolar lavage sampling,
exhaled breath condensate (EBC) is a promising non-invasive alternative to assess ROS-related physiological events.
Methods: A standardized method for simultaneous quantification of three biomarkers of oxidative damage to lipids and DNA: 8-
isoprostaglandin F2α (8-isoprostane), 8-hydroxy-deoxyguanosine and malondialdehyde in EBC was developed using liquid
chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS).
Results: Malondialdehyde was measured in EBC after derivatization with 2,4-dinitrophenylhydrazine. Electrospray ionization of
the analytes was obtained in positive-ion mode for malondialdehyde and 8-hydroxy-deoxyguanosine, and in negative-ion mode for
8-isoprostane. The different compounds were separated on a C18 column using variable proportions of mixture of methanol:
acetonitrile (7:3, v/v) and water. Limits of detection were in the 0.5–1.0 nM range.
Short discussion/conclusions: Considering that EBC is a strongly diluted sample (lining fluid content < 0.1%), the main
challenge consisted of optimizing the sample pre-concentration step to yield greater sensitivity and selectivity for the analysis of
target chemicals. The developed method will be further characterized through the analysis of EBC samples from control and
COPD subjects in order to evaluate the intra/inter-variability of the biomarkers’ values. Later on, the optimal context-of-use of the
three biomarkers detection in EBC – early diagnosis, personalized treatment and early-phase exacerbation alert – will be
determined in the frame of further clinical studies.