Glossary: collision energy
92 Orbitrap Fusion Series Hardware Manual Thermo Scientific
collision energy The energy used when ions collide
with the collision gas.
collision gas A neutral gas used to undergo collisions
with ions.
collision-induced dissociation (CID) A method of
fragmentation where ions are accelerated to high-
kinetic energy and then allowed to collide with
neutral gas molecules such as helium or nitrogen.
The collisions break the bonds and fragment the ions
into smaller pieces.
contact closure connection The cable connection is
from the external peripheral device to the mass
spectrometer contact closure pins (Start In and
Ground). The external device sends the contact
closure (start) signal to the mass spectrometer.
conversion dynode A highly polished metal surface
that converts ions from the mass analyzer into
secondary particles, which enter the electron
multiplier.
D
damping gas Helium gas introduced into the ion trap
mass analyzer that slows the motion of ions entering
the mass analyzer so that the ions can be trapped by
the RF voltage fields in the mass analyzer.
divert/inject valve A valve on the mass spectrometer
that can be plumbed as a divert valve or as a loop
injector.
E
electron multiplier A device used for current
amplification through the secondary emission of
electrons. Electron multipliers can have a discrete
dynode or a continuous dynode.
electron transfer dissociation (ETD) A method of
fragmenting peptides and proteins. In ETD, singly
charged reagent anions transfer an electron to
multiply protonated peptides within the ion trap
mass analyzer. This leads to a rich ladder of sequence
ions derived from cleavage at the amide groups along
the peptide backbone. Amino acid side chains and
important modifications such as phosphorylation are
left intact.
electrospray (ESI) A type of atmospheric pressure
ionization that is currently the softest ionization
technique available to transform ions in solution into
ions in the gas phase.
F
flow rate, syringe pump status The syringe pump
injection flow rate in milliliters per minute (mL/min)
or microliters per minute (μL/min) for the current
sample, as defined in the current experiment method.
forepump The pump that evacuates the foreline. A
rotary-vane pump is a type of forepump. It might
also be referred to as a backing, mechanical, rotary-
vane, roughing, or vacuum pump.
Fourier transform (FT) The mathematical operation
that converts the image current signal detected in an
ICR trap or Orbitrap mass spectrometer to a set of
m/z values. The Fourier components correspond to
ion mass and the Fourier coefficients correspond to
ion abundance.
Fourier Transform - Ion Cyclotron Resonance Mass
Spectrometry (FT-ICR MS [or FTMS]) A technique
that determines the mass-to-charge ratio of an ion by
measuring its cyclotron frequency in a strong
magnetic field.
fragment ion A charged dissociation product of an
ionic fragmentation. Such an ion can dissociate
further to form other charged molecular or atomic
species of successively lower formula weights.
full-scan type Provides a full mass spectrum within a
defined mass range.
G
gating of ions This process controls when the ions can
enter the ion trap mass analyzer.
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