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 300eV. For each mixture, major bimolecular ion-molecule reactions have been identified at total pressure from 0.5 to 33.3Pa. The main secondary ions: NH4+ (m/q = 18), H3S+ (m/q = 35) and 4 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. (c) 2007 Elsevier Ltd. All rights reserved.