OPTICAL SENSORS FOR CARBON DIOXIDE AND THEIR APPLICATIONS

There are few analytes in the world as significant as carbon dioxide, the basic chemical feedstock of life. Through green plant photosynthesis, carbon dioxide is converted to the fuel and food necessary for the continued existence of most known forms of life. In addition carbon dioxide is ail indicator of the existence of life and a measure of health via respiration. Not Surprisingly, therefore, one or the key, basic analytes routinely monitored in the blood of hospital patients is the level of dissolved carbon dioxide. The measurement of carbon dioxide levels is also ail important feature of environmental monitoring, providing, as it does, all important indicator of the health of the hydrosphere or atmosphere. The use, presence and measurement of carbon dioxide are also important in many industries, including brewing and the biotechnologics. In the food industry, a revolution in food packaging has come about through the use of carbon dioxide in modified atmosphere packaging (MAP). In many industries, the use, or presence, of carbon dioxide is commonplace and its measurement and continuous monitoring essential. In this article, the basic concepts behind the major, different colourimetric and luminescent optical sensors for the detection and quantitative analysis of carbon dioxide are reviewed and illustrated with examples. The major applications of these sensors are discussed and their strengths and weaknesses highlighted.