An efficient and reproducible method for measuring hydrogen peroxide in exhaled breath condensate

Abstract

We investigated the sensitivity and reproducibility of a test procedure for measuring hydrogen peroxide (H202) in exhaled breath condensate and the effect of storage of the condensate on the H2O2 concentration, and compared the results to previous studies. Twenty stable COPD patients breathed into our collecting device twice for a period of 10 min. The total exhaled air volume (EAV) and condensate volume were measured both times and the H2O2 concentration of the condensate was determined fluorimetrically. The concentration was measured again after freezing the reaction product at -70 degrees C for a period of 10, 20 and 40 days. We collected 2-5 ml condensate in 10 min. The EAV and condensate volumes were strongly correlated. There was no significant difference between the mean H2O2 concentration of the first and second test. We obtained a detect on limit for the H2O2 concentration of 0.02 micromoll(-1). The H2O2 concentration appeared to remain stable for a period up to 40 days of freezing. Compared to previous studies we developed a more efficient breath condensate collecting device and obtained a lower H2O2 detection limit. The measurement of exhaled H2O2 was reproducible. In addition, storage of the samples up to 40 days showed no changes in H2O2 concentration.

Reproducibility of oxidative stress biomarkers in breath condensate: are they reliable?

“…The other major factors that may affect the reproducibility would include intra-and inter-individual variability, sampling time and variability in dilution of respiratory droplets by water vapour [2]. The findings described in this study are not surprising, as many investigators have highlighted similar problems relating to the variation in reproducibility of these biomarkers in EBC [3,4]. The variations in the reproducibility of these biomarkers could be due to methodological issues regarding sampling, storage and analytical techniques of EBC.…”

Does Oxidative Stress Change During Orthotopic Liver Transplantation?

“…However, the reported concentrations of H 2 O 2 (70-150 mM), 8-iso-prostaglandin F 2α (20-30 pg/mL), and NO (presumably nitrite+nitrate; 20-35 µM) in EBC are in part much too high (26,27) and question the reported claims of elevation of oxidative stress upon reperfusion. The utility of 8-iso-prostaglandin F 2α in EBC as a biomarker of oxidative stress in human disease remains to be demonstrated (26).…”

Biomarkers in asthma and allergic rhinitis

“…However, an ATS/ERS task force addressed several issues resulting in novel EBC guidelines [85]. Several collectors and condensers are currently available [86][87][88][89][90]. All devices are easy to use and subsequent exhaled breath collection can be simply obtained from both young and elderly individuals.…”