Direct Determination of Gas pH and Carbon Dioxide Concentration with pH Electrodes

• Autores: Qinlan Yang, Jun Long, Hao Zheng, Xianqing Tian, Dean Lei, Xiaoqiong Zhu, Yong Guo, Dan Xiao
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 91, Nº 4, 2014, págs. 593-596
• Idioma: inglés
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• Resumen

  • A simple apparatus to measure gas pH and carbon dioxide (CO2) concentration was designed for undergraduate students in the analytical chemistry laboratory. Gas passed through a flow meter and a mixer, then reached the homemade measuring chamber and caused the potential change of a pH combination electrode. Poly(ethylene glycol)-20000 aqueous solutions with hygroscopicity and nontoxicity were used as reaction media by forming absorption liquid films around the junction point and the bulb of the pH combination electrode. A laboratory-made voltage follower and a N2000 chromatography data system were used to transform impedance and record data, respectively. Gas samples containing 10–100% CO2 were measured with the apparatus, and fast potential responses for different concentrations of CO2 were obtained. This apparatus is more cost-effective and eco-friendly as compared with other conventional methods.