Highly sensitive and selective colorimetric sensing of CO₂ for biomedical applications

The concentration of carbon dioxide (CO₂) in unhealthy people differs greatly from healthy people. High-precision CO₂ detection with a quick response time is essential for many biomedical applications. A major focus of this research is on the detection of CO₂, one of the most important health biomarkers. We investigated a low-cost, flexible, and reliable strategy by using dyes for colorimetric CO₂ sensing in this study. The impacts of temperature, pH, reaction time, reusability, concentration, and dye selectivity were studied thoroughly. This study described real-time CO₂ analysis. Using this multi-dye method, we got an average detection limit of 1.98 ppm for CO₂, in the range of 50-120 ppm. A portable colorimetric instrument with a smartphone-assisted unit was constructed to determine the relative red/green/blue values for real-time and practical applications within 15 s of interaction and the readings are very similar to those of an optical fiber probe. Environmental and biological chemistry applications are likely to benefit greatly from this unique approach.