Just Breathe

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In 1958, the invention of the modern “breathalyzer” provided a rapid, non-invasive way to estimate a person’s blood alcohol content by detecting ethanol in their breath. Since then, scientists have explored the use of breath to detect other things, such as cancer, diabetes, or infections—including COVID-19. To improve breath-based detection, scientists at Los Alamos are cataloguing the molecules found in healthy human breath to determine a baseline chemical profile.

Los Alamos scientists are using mass spectrometry techniques to analyze metabolite compounds in breath.

Human breath comprises nitrogen, oxygen, and carbon dioxide, but it also includes organic compounds called metabolites that are byproducts of metabolism. Through the Breath Profile Project, Los Alamos scientists are using mass spectrometry techniques to analyze metabolite compounds in breath. Mass spectrometers are instruments that measure the mass of each atomic species to reveal how many carbons are present, how many nitrogens, etc. The team is using a technique called tandem mass spectrometry that first breaks the target compounds into predictable-sized fragments. This tandem approach reliably identifies the exact molecules being examined—ultimately elucidating the precise metabolites that are present so the team can investigate their origin.

“It is really important for our team to identify why each compound could be there, not just report its existence,” says Los Alamos biologist Ethan McBride. Investigating the “why” involves searching through scientific literature, commercial product chemical inventories, and databases of metabolic pathways.

The Los Alamos team analyzed data from 31 volunteers at the Laboratory. The scientists identified 227 distinct breath features and a few trends: Four breath features were found to be strongly associated with females, and 37 features were associated with the time of day that the samples were taken. Ultimately, they identified 48 common features that could comprise a healthy breath profile. The team is currently partnered with the Department of Emergency Medicine at the University of New Mexico to gather another 50 volunteer samples, which will include both blood and breath data. Comparing features in blood and breath could bring new insight into how compounds are metabolized and circulate in the human body.

“The team partnered with Professor Justin Baca at the University of New Mexico to help us expand our volunteer base, and it also led to some exciting opportunities for us to study real clinical samples,” says Trevor Glaros, biologist and leader of the Biochemistry and Biotechnology Group at Los Alamos. 

With a reliable baseline of what is found in healthy breath, future work can more accurately detect what is not healthy by pinpointing chemical signatures of disease or impairment. Signature molecules are key to ultimately developing easy diagnostic tests where all a patient must do… is breathe.

People also ask

• How does a breathalyzer work?
  Breathalyzers detect ethanol molecules in a person’s breath providing a way to estimate the amount of alcohol in the person’s blood.
• Is bad breath normal?
  Yes! Certain foods or dental hygiene can contribute to unpleasant breath; however recent research shows that some molecules found in breath can be indicators health issues. Understanding which molecules are normal helps scientists identify molecules that are signs of disease.