Development of optical fiber based chlorophyll and anthocyanin coated carbon dioxide biosensor

The paper reports the development of low cost, portable and easily operable optical fiber based carbon dioxide biosensor (CO₂). The chlorophyll and anthocyanin is used as active clads. Coriander and red leaf amaranth (amaranth) contain photosynthetic pigments viz. chlorophyll and anthocyanin. Developed sensors selectively show CO₂ gas concentration dependent response from 1 to 500 ppm that is measured in terms of transmitted intensity through a plastic optical fiber. It is found that chlorophyll shows better response in terms of Sensitivity 1.571%/ppm than anthocyanin 0.667%./ppm. Thickness (Four layers) and clad length (7 mm) optimization is done for better sensitivity. Sensors show negligible response to humidity and methane gas. The sensor can be used when stored at room temperature (25⁰C) up to a maximum of 25 days giving 85 to 90% retention of the response.