METHOD AND APPARATUS FOR DETERMINING CONCENTRATION OF NITROGEN OXIDE(NO) IN GAZ MEDIUM Russian patent published in 2013 - IPC G01N21/76 

FIELD: chemistry.

SUBSTANCE: disclosed is the determination of concentration of nitrogen oxide in an analysed gas medium from the drop in concentration of an active form of oxygen, e.g. ozone (O₃), taken in excess with respect to concentration of nitrogen oxide contained in the analysed gas medium, fed into a reaction chamber into which a gas mixture is simultaneously fed with a stream of the analysed gas medium, said mixture containing a known amount of ozone, wherein chemical reaction of nitrogen oxide with ozone is carried out until complete conversion of nitrogen oxide to nitrogen dioxide, and from the drop in concentration of ozone in the obtained gas mixture, determined through a heterogeneous chemiluminescent method by blowing said gas mixture onto a solid-state chemiluminescent ozone sensor lying in the active zone of a photomultplier, concentration of nitrogen oxide in the analysed gas medium is determined. The solid-state chemiluminescent ozone sensor is in form of a substrate whose working surface is coated with a dry layer of a chemiluminescent selective composition in polyphenol and arylmethane dye, dissolved in a mixture of ethanol and ethylene glycol in equal proportions at concentration of 0.05-0.07 mol/l and 0.0003 mol/l, respectively, and after depositing on the substrate of the solid-state chemiluminescent ozone sensor, the chemiluminescent selective composition is dried to constant residual weight of the solid-state chemiluminescent ozone sensor. Also disclosed is an apparatus for implementing said method.

EFFECT: high uniformity of luminescence on the area of the solid-state chemiluminescent ozone sensor in a heterogeneous reaction zone at each time of measuring concentration of ozone in a sample of a gas medium, high accuracy of determining concentration of nitrogen oxide in a gas medium.

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