Determination of nitrogen oxides by reaction gas chromatography

The determination of nitrogen oxides as well as of nitrites, nitrates, and nitric acid is one of the difficult tasks related to analytical control in industry to the analysis of pollutants of the environment. The conversion of oxygenated nitrogen compounds into nitrobenzene has been used for the gas chromatographic determination of these compounds in exhaust gases from diesel engines and gunpowder gases. The nitrogen oxides were trapped and preconcentrated from air by reaction and sorption, a procedure based on the preliminary removal of interfering impurities from the analyzed air (gas) by means of a reactor-precolumn packed with a sorbent. This approach has significantly improved the selectivity and accuracy of the analysis.