A sensitive technique for the rapid measurement of carbon dioxide concentrations [Sorghum, respiration and photosynthetic studies]

A method has been developed to measure concentrations of CO2 in gases rapidly. A gas sample is injected into a flowing carrier gas that passes through an infrared CO2 analyzer. A strip chart recorded peak response is obtained which is proportional to the CO2 concentration. A resolution of better than 2 microliters of CO2 per liter of gas was obtained. Seven to 10 seconds were required for sample analysis once the sample was obtained. Sorghum bicolor plant respiration was determined at different temperatures by measuring CO2 using this system and by using a conventional system. The correlation between techniques was 0.996, and about the same variation occurred within each method. This technique greatly increased the efficiency of the infrared CO2 analyzer in our laboratory for use in plant respiration and photosynthetic studies.