Articles
Calibration Of Carbon Dioxide Analyzers
April 15, 2009
•Application Note: Calibration Of Carbon Dioxide Analyzers
By Hach Company
Every gas measuring instrument requires a method for calibration or verification.
Orbisphere manuals suggest several means for calibrating a CO2 analyzer. The easiest way is a gas calibration: pure CO2 gas at a known pressure is injected on the sensor membrane. This is a perfect method if the unknown sample is a gas.
However, if the analyzed sample is a liquid, a slight deviation from the actual value can be noticed: even though the Orbisphere CO2 sensor measures the CO2 partial pressure in the liquids, the presence of the liquid can have some effect on the temperature of the sensitive membrane and on the access of CO2 molecules to the membrane.
In practice, the CO2 measurements in liquid will indicate 1 or 2 % lower CO2 level than expected after a gas phase calibration.
One way to prevent this problem is to calibrate in the liquid phase, that's why Orbisphere has developed the CO2 calibration kits.
Click Here To Download:•Application Note: Calibration Of Carbon Dioxide Analyzers
