The theoretical basis and experimental evidence for a Stern-Volmer typ
e relationship using the fluorescence ratio (I-bl/I) in the absence (I
-bl) and presence (I) of CO2 as response function for fluorescence-bas
ed fiber-optic CO2 sensors is explored. By choosing the right indicato
r, appropriate bicarbonate concentration, and a thin enough sensing la
yer, a fiber-optic CO2 sensor with a usable linear range can be easily
achieved using I-bl/I as the response function. This allows the possi
bility of one-point calibration, which cannot be accomplished if the m
easured fluorescence intensity (I) is used directly as the response fu
nction.