The decomposition of NO and N 2O on Cu and Cu 2O packings was studied in view of the simultaneous determination of N and S in organic compounds by the Pregl-Dumas method in a system of reaction gas chromatography, and the mass balance of the reactions taking place was carried out. The amounts of NO and N 2O that are decomposed on the reduction packing at temperatures within 883 and 1263 °K are quoted. The reduction activity of both packings toward NO decreases with increasing temperature, while both the reduction and sorption activity of Cu 2O is markedly lower than that of the Cu one. No significant sorption of NO was observed at temperatures within 883 and 923 °K and no sorption of gaseous N 2 and N 2O occurred on either packing.