Fiber-optic sensors were developed for monitoring dissolved carbon dio
xide in water samples in the 0 to 900 ppm concentration range, A pH-se
nsitive fluorescent dye (HPTS) was reacted with a cationic quaternary
ammonium salt to form an ion pair which was electrostatically bound to
the surface of particles of aminocellulose which then were dispersed
into a gas-permeable silicone polymer. The green fluorescence of the b
ase form was monitored using a fiber optic fluorometer. The use of the
aminocellulose enhanced the stability and lifetime of the sensor and
also increased the fluorescence of the sensor membrane because the par
ticles act as scattering centers. The characteristics of the sensors a
re described with respect to dynamic range, reproducibility, long-term
stability and temperature dependence.