Technical data

Overview 1
Atmospheric pressure chemical ionization (APCI)
Agilent 6200 Series TOF and 6500 Series Q-TOF LC/MS System Concepts Guide 23
APCI is applicable across a wide range of molecular polarities.
It rarely results in multiple charging, so it is typically used for
molecules less than 1,500 u. Because of this molecular weight
limitation and use of high-temperature vaporization, APCI is
less well-suited than electrospray for analysis of large
biomolecules that may be thermally unstable. APCI is well
suited for ionization of the less polar compounds that are
typically analyzed by normal-phase chromatography.