Affiliation:
1. Department of Chemistry Southern University of Science and Technology 1088 Xueyuan Boulvard Shenzhen 518055 P. R. China
2. Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology 1088 Xueyuan Boulvard Shenzhen 518055 P. R. China
Abstract
AbstractWe report here a colorimetric carbon dioxide (CO2) optode sensor with a polypropylene microporous membrane on top of a thin layer (30 μm) of polyurethane hydrogel. The diffusion of CO2 across the polypropylene membrane induced pH changes in the hydrogel containing a lipophilic indicator, a cation exchanger, and a cationic amine. The ratio of the indicator and the cation exchanger was successfully utilized to adjust the sensitivity of the CO2 response. Increasing the relative amount of the cation exchanger made the sensor much more sensitive to CO2 in the lower concentration range. Moreover, the carbarmic formation reaction between the primary amine and CO2 was investigated. The results indicated a very small contribution of carbarmic formation to the overall pH change. With a detection limit of 0.014 % for the CO2 partial pressure, the sensor was successful applied to monitor CO2 evolution during yeast catalyzed flour fermentation.
Funder
National Key Research and Development Program of China
Guangdong Provincial Department of Science and Technology