Patent ID: 6362005
Filing Date: 2002-03-26
Classification: G01N,Y10T

Abstract:
A nitrogen dioxide gas sensing method comprising:the first step of preparing a sensor element in which a mixture of a diazotizing reagent which reacts with nitrous ions to produce a diazo compound, a coupling reagent which couples with the diazo compound to produce an azo dye, and an acid is placed in pores of a transparent porous body, wherein the sensor element is capable of detecting nitrogen dioxide gas when the sensor element is in a dry state, and an average pore-diameter of said porous body allows said diazotizing reagent and said coupling reagent to enter the pores and is not more than 20 nm; the second step of measuring a light transmittance of said sensor element to calculate a first transmittance; the third step of exposing said sensor element to air top be measured for a predetermined time; the fourth step of measuring a light transmittance of said sensor element to calculate a second transmittance after the third step; and the fifth step of sensing nitrogen dioxide gas in the air to be measured in accordance with a difference between the first and second transmittances.