Active Capillary Dielectric Barrier Discharge Ionization: Investigation of the Ionization Mechanism(s)

摘要

Our results clearly show that the DBD source yields protonated ions even in the absence of water, but when water is present, it is preferred as H+-donor. Therefore the underlying mechanism does not necessarily require H3O+ as stipulated for SESI or APCI. Overall we suggest a "soft" electron impact based mechanism, where the positively charged intermediate analyte species are stabilized by proton abstraction from whichever surrounding molecule.