Radio-Frequency Glow Discharge Ion Trap Mass Spectrometry

A radio-frequency glow discharge Ion source has been interfaced with a three-dimensional quadrupole ion trap. Data are described for ions derived from brass and multicomponent glass standards. These data iIndicate that the ion trap has some interesting features as a mass analyzer for Ions formed In a glow discharge. MS/MS efficiencies approaching 100% for oxides and hydroxides of all metal ions studied were observed. Ions derived from the argon support gas, such as ArH⁺, Ar²⁺, and Ar₂ ^*+, were depleted in the ion trap by rapid electron- and proton-transfer reactions to background gases In the Ion trap. The mass/charge ratios of the terminal Ions in the sequence of reactions fell below the lower mass limit of the Ion trap and were quickly elected. The use of mass-selective Ion Injection techniques permitted the analysis of components present at levels as low as a few tens of parts per million. However, chemical noise due to relatively high background pressures in the ion source precluded analysis of components of lesser abundance.