| Time-of-flight |
TOF |
Time dispersion of a pulsed
ion beam; separation by the time it takes for ions to travel a fixed
distance |
High-speed
analysis, large
mass range and good sensitivity. Suited for fast data acquisition
and high-throughput applications. Modern TOF systems usually can achieve
mass resolution well over 10,000 (m/Δm) or even higher. |
| Linear quadrupole |
Q |
Continuous ion beam in linear
radio frequency quadrupole field; separation due to instability of
ion trajectories; rods have applied alternating DC and RF |
High transmission efficiency,
simple design, good sensitivity, and tunable mass range; relatively
low mass resolution ranges from several hundreds to a thousand; often
used in tandem mass spectrometry (MS/MS) experiments |
| Quadrupole ion
trap |
QIT |
Traps ions by electromagnetic
fields; separation in three-dimensional radio frequency quadrupole
field by resonant excitation |
Efficient for fragmenting
ions and structural elucidation, higher sensitivity, and relatively
compact which good for benchtop instruments. Relatively a low mass
resolution around 1000–3000. |
| Fourier transform-ion cyclotron
resonance |
FT-ICR |
Traps ions in a strong magnetic
field by Lorentz force; separation by cyclotron frequency, image current
detection and Fourier transformation of transient signal |
Ultimate high mass resolution
(over 2,700,000 with 21 telsa magnets), making it ideal for elemental
and isotopic analysis. Large size, low speed, and expensive in terms
of both initial purchase cost and ongoing operation and maintenance
costs. |
| Orbitrap |
Orbitrap |
Axial oscillation in inhomogeneous
electric field; detection of frequency after Fourier transformation
of transient signal |
Extremely high resolution
and accuracy (up to 1,000,000), capable of resolving complex mixtures
with high sensitivity. Relatively low speed, expensive in terms of
both initial purchase cost and ongoing operation and maintenance costs.
Need high vacuum. |
