Attenuation of Polyatomic Ion Interferences in Inductively Coupled Plasma Mass Spectrometry by Gas-Phase Collisions

A double quadrupole arrangement to remove polyatomic ions by collisions with an added target gas has been evaluated. The ions Ar 2 + , ArO + , and ArN + were attenuated by factors of 50–400 to count rates of ≤100 counts s −1 . Fifty to seventy percent of the analyte ions were retained. Removal of polyatomic ions and retention of analyte ions were favored by low-energy collisions with Xe or CH 4 rather than typical target gases like N 2 or Ar. Products of ion-molecule reactions between background ions and target gas in the first quadrupole could be observed.