1 research outputs found
Decreased Gap Width in a Cylindrical High-Field Asymmetric Waveform Ion Mobility Spectrometry Device Improves Protein Discovery
High-field asymmetric waveform ion
mobility spectrometry (FAIMS)
is an atmospheric pressure ion mobility technique that separates gas
phase ions according to their characteristic dependence of ion mobility
on electric field strength. FAIMS can be implemented as a means of
automated gas-phase fractionation in liquid chromatography-tandem
mass spectrometry (LC-MS/MS) experiments. We modified a commercially
available cylindrical FAIMS device by enlarging the inner electrode,
thereby narrowing the gap and increasing the effective field strength.
This modification provided a nearly 4-fold increase in FAIMS peak
capacity over the optimally configured unmodified device. We employed
the modified FAIMS device for on-line fractionation in a proteomic
analysis of a complex sample and observed major increases in protein
discovery. NanoLC-FAIMS-MS/MS of an unfractionated yeast tryptic digest
using the modified FAIMS device identified 53% more proteins than
were identified using an unmodified FAIMS device and 98% more proteins
than were identified with unaided nanoLC-MS/MS. We describe here the
development of a nanoLC-FAIMS-MS/MS protocol that provides automated
gas-phase fractionation for proteomic analysis of complex protein
digests. We compare this protocol against prefractionation of peptides
with isoelectric focusing and demonstrate that FAIMS fractionation
yields comparable protein recovery while significantly reducing the
amount of sample required and eliminating the need for additional
sample handling