1 research outputs found
Phonon-Assisted Field Emission in Silicon Nanomembranes for Time-of-Flight Mass Spectrometry of Proteins
Time-of-flight (TOF) mass spectrometry
has been considered as the
method of choice for mass analysis of large intact biomolecules, which
are ionized in low charge states by matrix-assisted-laser-desorption/ionization
(MALDI). However, it remains predominantly restricted to the mass
analysis of biomolecules with a mass below about 50 000 Da.
This limitation mainly stems from the fact that the sensitivity of
the standard detectors decreases with increasing ion mass. We describe
here a new principle for ion detection in TOF mass spectrometry, which
is based upon suspended silicon nanomembranes. Impinging ion packets
on one side of the suspended silicon nanomembrane generate nonequilibrium
phonons, which propagate quasi-diffusively and deliver thermal energy
to electrons within the silicon nanomembrane. This enhances electron
emission from the nanomembrane surface with an electric field applied
to it. The nonequilibrium phonon-assisted field emission in the suspended
nanomembrane connected to an effective cooling of the nanomembrane
via field emission allows mass analysis of megadalton ions with high
mass resolution at room temperature. The high resolution of the detector
will give better insight into high mass proteins and their functions