Rapid responsible optical CO_2 sensor of the combination of colorimetric change of α-naphtholphthalein in poly(trimethylsiliylpropyne) layer and internal reference fluorescent porphyrin in polystyrene layer

摘要

An optical CO_2 sensor based on the overlay of the CO_2 induced absorbance change of pH indicator dye α-naph-tholphthalein in poly(trimethylsiliypropyne) (poly(TMSP))layer with the fluorescence of tetraphenylporphyrin (TPP) in polystyrene layer is developed. The observed luminescence intensity from TPP at 655 nm increased with increasing the CO_2 concentration. The ratio I_(100)/I_0 value of the sensing film, where I_0 and I_(100) represent the detected luminescence intensities from a layer exposed to 100% argon and 100% CO_2, respectively, that the sensitivity of the sensor, is estimated to be 10.3. The response and recovery times of the sensing film are less than 3.0 s for switching from argon to CO_2, and for switching from CO_2 to argon. The signal changes are fully reversible and no hysteresis is observed during the measurements. The highly sensitive and fast responsible optical CO_2 sensor based on fluorescence intensity changes of TPP due to the absorption change of α-naphtholphthalein with CO_2 is achieved using poly(TMSP) film.