High-pressure mass spectrometric investigations of ion–molecule reactions in hydrogen sulfide and ammonia mixtures

The positive ion–molecule reactions in the mixtures of hydrogen sulfide and ammonia have been examined by means of quadrupole mass spectrometer with high-pressure ion source. The concentration of hydrogen sulfide in mixtures ranged from 10% to 90% with 10% increment. Mainly observed primary ions: NH2+ (m/q=16), NH3+ (m/q=17), S+ (m/q=32) and H2S+ (m/q=34) were formed as the result of ionization and dissociative ionization by electrons with energy of 300 eV. For each mixture, major bimolecular ion–molecule reactions have been identified at total pressure from 0.5 to 33.3 Pa. The main secondary ions: NH4+ (m/q=18), H3S+ (m/q=35) and NH3S+ (m/q=49) were observed.Relative intensities of ion currents for observed ions were determined as a function of total gas pressure inside ion source collision chamber, repeller potential and concentration of hydrogen sulfide in the mixture.