Front Cover: A Tunable Colorimetric Carbon Dioxide Sensor Based on Ion-Exchanger- and Chromoionophore-Doped Hydrogel (Anal. Sens. 6/2023)

The cover feature image shows a two-dimensional (2D) colorimetric carbon dioxide (CO₂) sensor composed of a gas-permeable polypropylene film (25 μm thick) and a signal transduction hydrogel layer (30 μm thick). The hydrogel layer contained a pH sensitive chromoionophore to indicate the CO₂ induced pH change, and a cationic amine to further capture CO₂ through the carbamate formation reaction. With this 2D colorimetric CO₂ optode, the CO₂ release from yeast-catalyzed flour fermentation was successfully monitored. More information can be found in the Research Article by Jingying Zhai, Xiaojiang Xie, and co-workers.