The Severinghaus electrode is an electrode that measures carbon dioxide (CO2). It was developed by Dr. John W. Severinghaus and his technician A. Freeman Bradley in 1958. It utilizes a CO2-sensitive glass electrode in a surrounding film of bicarbonate solution covered by a thin plastic carbon dioxide permeable membrane, but impermeable to water and electrolytic solutes. The carbon dioxide pressure of a sample gas or liquid equilibrates through the membrane and the glass electrode measures the resulting pH of the bicarbonate solution.
CO 2 + H 2 O ↽ − − ⇀ H 2 CO 3 ↽ − − ⇀ HCO 3 − + H + {\displaystyle {\ce {CO2 + H2O <=> H2CO3 <=> HCO3- + H+}}}
Clark, galvanic, and paramagnetic electrodes measure oxygen. Severinghaus electrode measures CO2. Sanz electrode measures pH.
References
External links Editorial, Anaesthesia UK (3 April 2006). "Anaesthesia UK : Measurement of pO2, pCO2, pH, pulse oximetry and capnography". Anaesthesia UK.