Quantitative GC–TCD Measurements of Major Flatus Components: A Preliminary Analysis of the Diet Effect

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 3; p. 838
• Main Authors: Freire, Rafael, Mego, Marianela, Oliveira, Luciana Fontes, Mas, Silvia, Azpiroz, Fernando, Marco, Santiago, Pardo, Antonio
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22.01.2022; MDPI
• Subjects: Biogas; Biomarkers; Carbon Dioxide; Catheters; Chemical Sciences; Chromatography, Gas; Colon; Cross-Over Studies; Diet; diet effect on flatus; Feces; Flatulence; Gas absorption; Gases; Humans; Hydrogen; major flatus gas components; Measurement; Metabolism; Methane; Microbiota; Microbiota (Symbiotic organisms); multilevel principal component analysis; Natural gas; Nitrogen; rectal gas collection; Sensors; Thermal Conductivity; Spain; diet effect on flatus; rectal gas collection; major flatus gas components; multilevel principal component analysis
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22030838

The impact of diet and digestive disorders in flatus composition remains largely unexplored. This is partially due to the lack of standardized sampling collection methods, and the easy atmospheric contamination. This paper describes a method to quantitatively determine the major gases in flatus and their application in a nutritional intervention. We describe how to direct sample flatus into Tedlar bags, and simultaneous analysis by gas chromatography–thermal conductivity detection (GC–TCD). Results are analyzed by univariate hypothesis testing and by multilevel principal component analysis. The reported methodology allows simultaneous determination of the five major gases with root mean measurement errors of 0.8% for oxygen (O2), 0.9% for nitrogen (N2), 0.14% for carbon dioxide (CO2), 0.11% for methane (CH4), and 0.26% for hydrogen (H2). The atmospheric contamination was limited to 0.86 (95% CI: [0.7–1.0])% for oxygen and 3.4 (95% CI: [1.4–5.3])% for nitrogen. As an illustration, the method has been successfully applied to measure the response to a nutritional intervention in a reduced crossover study in healthy subjects.