Intensity- and lifetime-based luminescence optosensing of carbon dioxide

摘要

The state-of-the-art of carbon dioxide fiberoptic sensing, using both steady-state and time- resolved luminescence measurements, is briefly reviewed. Particular emphasis is given to the authors' own research on carbon dioxide optical monitoring via an excited-state proton transfer to luminescent ruthenium (II) chelate complexes. This kind of pH transduction chemistry allows for determination of the analyte in gas or liquid phase using both emission intensity- and lifetime-based optodes using the technology (sources, detectors, electronics) already developed for optical fiber oxygen sensing. Relevant factors that affect the performance of CO$-2$/ luminescent optosensors, such as the structure of the indicator dye, the immobilization procedure and support, the internal buffer of the sensitive layers and the working principle, are discussed as well. Finally, some recent applications in the authors' laboratories to fiberoptic carbon dioxide monitoring in spring water samples are presented.