Optical Detection of Nitrogen Monoxide by Metal Porphine Dispersed in Amorphous Silica Film

Abstract
New optical detection of nitrogen monoxide was developed using cobalt α, β, γ, δ-tetrakis (5-sulfothienyl) porphine which was doped in a silica thin film by a sol–gel method. The absorption band at λ=420 nm was weakened significantly by a contact with gaseous NO at 200 °C but was not sensitive to O2 and CO. The band change was completely reversible and depended on the pressure of NO in the pressure range of 1.3 to 3.2×103 Pa.