Methods and apparatus for simultaneously producing and electronically separating the chemical ionization mass spectrum and the electron impact ionization mass spectrum of the same sample material

摘要

A method and apparatus for mass spectrometry employing tandem chemical ionization (CI) and electron impact (EI) ionization chambers with independent ionizing electron sources, both CI and EI ions being produced simultaneously. Through electronic shuttering either the CI or EI ions may be transmitted to the mass spectrometer while the ions of the other type are dispersed and rejected. The shuttering being accomplished very rapidly relative to the mass scan rate, which is in turn fast with respect to temporal variations in sample material composition. The two interwoven ion sequences are demultiplexed and smoothed into independent and effective simultaneous CI and EI mass spectrum channels.