抄録
An ion mobility/mass spectrometer that incorporates a drift tube and a quadrupole mass analyzer has been developed for the purpose of identifying ion species in the experiments of ion-induced nucleation and also in the ambient tropospheric air. Total ion mobility spectra, mass spectra, and mass-resolved mobility spectra were measured for positive ions aged for 20-30 ms in the laboratory air. The results showed that NH4+ (H2O)n were dominant ions and were responsible for the most intense ion peak (1.66×10-4m2V-1s-1) in total ion mobility spectra. Protonated dimethylamine (46 amu) and protonated pyridine (80 amu) were also found in the mass spectra along with several unidentified ions (135, 149, 152, 279 amu). Mass-resolved mobility spectra of ions other than NH4+ (H2O)n appeared to reflect changes in the ion composition within the drift tube, indicating that information on ion-molecule reactions in the drift tube can be obtained from analysis of mass-resolved mobility spectra.
