A potentiometric NO sensor principle based on NO+ cation conducting beta "
-alumina is presented. Main part of the sensor is a nitrosyl (NO+) cation c
onducting membrane generating a potential difference between two different
NO partial pressures by the reaction NO <----> NO+ + e(-). If the membrane
is situated as a separator between a reference gas and a measuring gas, a N
ernstian behavior with a slope close to n = 1 in a semi-logarithmic plot (n
is the number of electrons involved in the reaction) can be found. The Ner
nstian behavior was verified in a NO partial pressure range of 10-1000 Pa (
100-10,000 ppm NO) with several reference partial pressures. The cross sens
itivity to oxygen, water, carbon monoxide and carbon dioxide was determined
and found, with the exception of oxygen, to be as low as expected from a N
O+ selective ion conducting membrane. (C) 2001 Elsevier Science B.V. All ri
ghts reserved.