Application of a solid electrolyte CO₂ sensor for the analysis of standard volatile organic compound gases

Preparation and analysis of standard VOC (volatile organic compound) gases are needed when developing and evaluating the performance of analytical methods or instruments to detect VOCs. In this study, we designed and developed a simple system for the analysis of VOCs based on their decomposition into CO ₂ by a combustion catalyst and their subsequent detection using a solid electrolyte CO₂ sensor. In this sensor, NASICON (Na ₃Si₂Zr₂PO₄; Na⁺ conductor) and binary carbonate (Li₂CO₃?BaCO₃) were used as the solid electrolyte and the sensing layer, respectively. This developed system proved to be effective in determining the concentrations of standard gases, including VOCs (ethanol, formaldehyde, and toluene), CO, and hydrocarbons in parts per million concentrations (10?500 ppm). The system also could continuously monitor the variations in ethanol vapors prepared by a diffusion method where liquid ethanol was heated at 25 and 50 C. The advantages and limitations of our developed analytical system are also discussed.