Miniature (Less Than 101 micrometers - 25 micrometers) Fiber Optic Chemical Sensors for the In situ Measurement of CO2 in Plants

摘要

The research has shown that 50 micrometer sensors can be made and has defined what must be done to make them as small as 5 micrometers. The best CO2 Fiber Optic Chemical Sensors (FOCS) are those that have hydroxypyrenetrisulfonyl chloride (HPTS) attached to the sides of the fiber optic with a surface amplification polymer. These sensors are completely reversible and have a response time of about 2 minutes. The change in HPTS fluorescence intensity is directly related to CO2 concentration. Single mode fibers must be used for the smaller sensors. In general, these fiber optics have poor light transmission because of the small fiber size; have little to no light transmission at 450 nm where HPTS is excited or at 520 nm where it emits its return signal; and are very brittle and difficult to handle. These drawbacks can be minimized by welding a small section of single mode fiber to a multimode cable.