Detection of dissolved CO2 gas using an open-circuit resonator
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Richardson, L.; Villafana-Ibarra, B. 2021. Detection of dissolved CO2 gas using an open-circuit resonator -- In Proceedings: 17th Annual Symposium on Graduate Research and Scholarly Projects. Wichita, KS: Wichita State University
Exposure to higher than normal levels of carbon dioxide (CO2) gas increases its concentration in the blood, which can impair cognitive function and cause adverse physical effects. This is especially a concern in aerospace applications with controlled air environments, like spacecraft interiors, where ambient CO2 levels are higher- making blood CO2 testing in these environments important. Current methods for measuring blood CO2 levels are invasive, require operator training, or are relatively inaccurate. This study examined the possibility of using a spiral electromagnetic resonance antenna, which has shown potential in other biomedical imaging applications, to detect the levels of CO2 gas dissolved in a liquid. A spiral resonator antenna was attached to a sealed flask filled with water and connected by a tube to another sealed flask in which acetic acid was mixed with varying amounts of sodium bicarbonate to create varying amounts of CO2 gas. Once the mixture fully reacted and the gas was dissolved into the water in the flask, the self-resonant response of the antenna attached to the flask was measured across sweeps of frequencies. The resonant frequency measured by the antenna was shown to vary significantly with the amount of CO2 dissolved in the water, demonstrating the sensor's capability for detecting the dissolved gas. These findings encourage further testing for using this antenna to detect CO2 dissolved in blood or a blood analogue and demonstrate potential for using this technology for a non-invasive CO2 blood gas sensor, like a patch placed against the skin.
Presented to the 17th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held online, Wichita State University, April 2, 2021.
Research completed in the Department of Biomedical Engineering, College of Engineering