Used primarily for small organic analytes and low polarity materials. The instrument is equipped with electron ionization (EI), chemical ionization (CI), and field ionization/field desorption (FI/FD) ion sources. The instrument has a mass range up to 800m/z in EI, CI and FI modes and up to 4,000m/z in FD mode. Accurate mass measurement (< 3 mDa) for elemental composistion confirmation is available in Ei, CI and FI modes. The GCT Premier runs with an Agilent 7890 Gas Chromatograph with autosampler in "walk up" access mode when not operated in solids probe mode by facility staff.