Analytical Sciences

Analysis of Nitrogen-containing Compounds in Mouth-exhaled Breath by Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry

Wenzhao ZHOU,* Yan HONG,** Xue ZOU,* Lei XIA,* Yan LU,* Chengyin SHEN,* Chaoqun HUANG,* and Yannan CHU*

*Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, P. R. China
**School of Electrical and Information Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001, P. R. China

Nitrogen-containing compounds are important components in human breath. However, their origins have not yet been clearly understood. In this study, a modified electrospray ionization (ESI) source coupling with quadrupole time-of-flight mass spectrometry has been used for breath analysis. Fourteen nitrogen-containing compounds were identified in mouth-exhaled breath, and 10 of them were from the oral cavity and oropharynx. Moreover, 8 of these nitrogen-containing compounds were recognized as endogenous metabolites. This result provides important clues for exploring the biological origins of these nitrogen-containing compounds. Observation of the ion suppression phenomenon also indicates that breath analysis should be carried out after clearing of the oral cavity and oropharynx, or directly through nose-breathing to eliminate the influence of those nitrogen-containing compounds from the oral cavity.

J-STAGE: View this article in J-STAGE