Abstract
In the mass spectrum of pure oxygen, peaks which do not belong to those based on oxygen itself were observed at M/e=12, 14, 28 and 44. These peaks were believed to be attributed to carbon monoxide and carbon dioxide formed by oxygen decarbiding the tungsten filaments in the ion source and ionization vacuum gage.
Because the spectrum of oxygen contributes to the spectra of impurities, it is difficult to determine small amounts of impurities in oxygen by a mass spectrometer without concentrating impurities. Therefore, highly pure oxygen was analyzed by a mass spectrometric measurement of residual gases after absorption of oxygen with metallic copper (700°C) using helium as the internal standard. Nitrogen, 0.020.2%, and argon, 0.010.4%, were found in commercial compressed oxygen.
