CHEMICALLY AND MECHANICALLY RESISTANT CARBON-DIOXIDE OPTRODE BASED ONA COVALENTLY IMMOBILIZED PH INDICATOR

An optical chemical sensor for dissolved carbon dioxide has been devel oped whose dynamic range was adjusted to CO2 partial pressures ranging from 0 to 100 hPa. The change in the pH of a buffer layer, caused by diffusion of carbon dioxide through a hydrophobic membrane, is indicat ed by the colour change of a covalently immobilized dye, and monitored through optical fibers. The sensor also incorporates an optical insul ation with a resplendent pigment to increase the reflectivity and to r educe adverse effects of straylight and ambient light. Two methods for layer manufacturing (spreading and spin coating) are described. The s ensor membrane is fully LED compatible. The optrode shows a promising performance with respect to chemical and mechanical long term stabilit y, reproducibility, and sterilizability.