Combination of chemical ionization and low energy ionization capabilities with high-resolution Q-TOF GC/MS

Important applications for high-resolution gas chromatography mass spectrometer (GC/MS) systems include untargeted screening approaches as well as unknown compound identification. For many classes of compounds, low energy electron ionization (EI) provides significant improvements in the relative abundance of molecular ions compared to standard (70 eV) EI, and enables enhancement in selectivity and compound identification capability without any down time due to changing the ion source or additional tuning. However, there is still an opportunity for alternative ionization sources as a complimentary technique (that is, chemical ionization), combined with high-resolution GC/MS, predominantly for selected compounds of environmental significance. In this work, a comparison of low energy EI and chemical ionization (CI) data acquired on the Agilent 7250 GC/Q-TOF will be reviewed.