Optical detection of nitrogen monoxide by metal porphine dispersed in an amorphous silica matrix

Abstract Optical detection of nitrogen monoxide has been investigated using cobalt α,β,γ,δ-tetrakis (5-sulfothienyl) porphine, which is doped in a silica thin film by a sol—gel method. The absorption band at λ = 420 nm is weakened significantly by contact with gaseous NO at 200 °C but is not sensitive to O 2 and CO. The band change is reversible and depends on the pressure of NO in the pressure range 1.3 to 3.2 × 10 3 Pa.