Analysis of volatile organic compounds in the human breath with micro extraction techniques and continuous monitoring of carbon dioxide concentration

The detection of volatile organic compounds (VOCs) in the human breath can be useful for clinical routine diagnosis of several diseases in a non-invasive manner. Traditional methods of breath analysis have some major technical problems and limitations. Membrane extraction with a sorbent interface (MESI) has many advantages, including good selectivity and sensitivity, and is well suited for breath analysis.;The use of breath CO2 as an internal standard for breath VOC analysis is an effective method to solve the difficulties associated with variations in analyte concentrations due to mass losses and different breathing patterns. The concentration of breath acetone was successfully normalized to CO2, as in the alveolar air. Acetone in the breath of healthy males and females profiled at different times of the day were plotted using the MESI system, and results were found to be consistent with literature references. This technique can be used for monitoring the acetone concentration in the breath of diabetic patients and for other biomarker monitoring.;The goal of this project was to develop a simple and reproducible sampling device and method based on the MESI system for breath analysis. The feasibility and validity of the MESI system was tested with real human breath samples in this study. Internal standard calibration methods were used for the quantitative analysis of breath samples. Calibration curves for several main components (target analytes such as acetone and isoprene) were also developed. Finally, optimized stripping side and feeding side gas velocities were determined.