Removal of metabolite interference during liquid chromatography/tandem mass spectrometry using high-field asymmetric waveform ion mobility spectrometry

The effect of metabolite interference during liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis of an amine drug was investigated using FAIMS (high‐Field Asymmetric waveform Ion Mobility Spectrometry). The selected reaction monitoring (SRM) transition used for the drug exhibited an interference due to in‐source conversion of the N‐oxide metabolite to generate an ion isobaric with the drug. The on‐line FAIMS device removed the metabolite interference before entrance to the mass spectrometer. FAIMS was used to demonstrate the relative accuracy and precision of drug analysis even in the presence of a co‐eluting metabolite that may undergo in‐source conversion. Copyright © 2005 John Wiley & Sons, Ltd.