Reaction Mechanism of Nitrogen Compounds in Gaseous Ethylene Followed by Catalytic Combustion-Chemiluminescence

Herein, a practical method for the determination of various organic and inorganic nitrogen (N) compounds in gaseous ethylene was established via the catalytic combustion-chemiluminescence technique. First, the regularity of equal N mass/molar response for N compounds was summarized by evaluating the conversion behavior of different speciation (bipyridine, acetonitrile, NO, NO₂, NH₃, N₂O). Then, based on the assumption that N response is unaffected by speciation, the actual N mass in gaseous samples was accurately calculated using the Van der Waals equation (to correct gas mass), and the theoretical N mass was derived from standard curves. As a result, the recoveries of N compounds at different levels were in the range of 106.0%-108.8% (15.0 μmol/mol acetonitrile), 103.2%-106.0% (24.1 μmol/mol NO), 100.1%-102.5% (10.1 μmol/mol N₂O + 10.1 μmol/mol NO₂), and 90.1%-95.5% (51.0 μmol/mol NH₃), successfully verifying the above assumption without the need to rebuild quantitative relationships for different N systems. In addition, the N detection limit (S/N = 3) in ethylene was 0.03 mg/kg, with intraday and interday relative standard deviations (RSDs) of 1.0%-2.3%. Finally, the reaction mechanism based on system passivation and catalytic combustion was successfully applied to unify various nitrogen compounds analysis, achieving gas-liquid equal mass/molar response.