There are two primary types of CO2 sensor in the METTLER TOLEDO portfolio.
For bioreactors and pharmaceutical production, the InPro 5000i is a dissolved CO2 probe that provides real-time CO2 values based on the technology of the Severinghaus principle, which utilizes the correlation between dissolved carbon dioxide and pH of a liquid. The sensing electrode is an enhanced pH electrode separated from the measurement media by an electrolyte-filled chamber and gas permeable membrane. CO2 diffuses through the membrane and into the inner electrolyte of the dissolved carbon dioxide sensor, where it equilibrates with bicarbonate ions, altering the pH value. The relative change in pH value of the electrolyte is then measured by the enhanced pH electrode and correlated to the CO2 value.
For brewing, the InPro 5500i is a thermal conductivity CO2 sensor that provides reliable in-line measurement of dissolved carbon dioxide that can be directly integrated into the brewing or beverage production process.