Ion mobility spectrometry-mass spectrometry

Ion-mobility spectrometry–mass spectrometry (IMS-MS) is a method that combines ion-mobility spectrometry and mass spectrometry

Mass spectrometry

Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...

to identify different substances within a test sample.

History

On the one hand, ion-mobility spectrometry was developed in the 60s and typically separates charged particles on a millisecond scale. On the other hand, time-of-flight mass spectrometry

Time-of-flight mass spectrometry

Time-of-flight mass spectrometry is a method of mass spectrometry in which an ion's mass-to-charge ratio is determined via a time measurement. Ions are accelerated by an electric field of known strength. This acceleration results in an ion having the same kinetic energy as any other ion that has...

was developed in the 50s and typically separates charged particles on a microsecond scale.
The combination of both instruments was pioneered in 1963 at the Bell Labs

Bell Labs

Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

In 1963 McAfee and Edelson published an IMS-TOF combination. From their Letter to the Editor it is not conclusive whether they used an orthogonal extraction TOF. Most likely it was, because they seem to have used the TOF of the company Bendix, which was an orthogonal TOF.
In 1967 McKnight, McAfee and Sipler published an IMS-TOF combination. Their instrument clearly included an orthogonal TOF.
In 1969 Cohen et al. filed a patent on an IMS-QMS system. The QMS at that time was an improvement compared to the TOFMS, because the TOFMS lacked under the slowlyness of the electronic data acquisition systems at that time.
In 1970, Young, Edelson and Falconer published an IMS-TOF with orthogonal extraction. They seem to have used the same system as McKnight et al. in 1967, incorporating slight modifications. Their work was later reproduced in the landmark book of Mason/McDaniel, which is regarded as the “bible of IMS” by those skilled in the art.
In 1996 Guevremont et al. presented a poster at the ASMS conference about IMS-TOF.
In 1997 Tanner patented a quadrupole with axial fields which can be used as a drift cell for IMS separation. He also mentions the combination of these quadrupoles with an orthogonal TOFMS.
In 1998 Clemmer reinvented the IMS-TOF combination, using a co-axial IMS-TOF setup.
In 1999 Clemmer reinvented the IMS-TOF with an orthogonal TOF system.

Instrumentation

The IMS-MS is a combination of an ion-mobility spectrometer and a mass spectrometer.
First the ion mobility spectrometer separates ions according to their mobilities. In a second step the mass spectrometer separates ions according to their mass-to-charge ratio

Mass-to-charge ratio

The mass-to-charge ratio ratio is a physical quantity that is widely used in the electrodynamics of charged particles, e.g. in electron optics and ion optics. It appears in the scientific fields of lithography, electron microscopy, cathode ray tubes, accelerator physics, nuclear physics, Auger...

. Such a combination is often referred to as a hyphenated separation or multi-dimensional separation.

There are different types of ion mobility spectrometers and there are different types of mass spectrometers. In principle it is possible to combine every type of the former with any type of the later.

Types of IMS

TOFIMS (time-of-flight IMS) or the traditional ion mobility spectrometer
DMS differential mobility spectrometer: a scanable filter, also called FAIMS
High-field asymmetric waveform ion mobility spectrometry
High-field asymmetric-waveform ion-mobility spectrometry is a mass spectrometry technique in which ions at atmospheric pressure are separated by the application of a high-voltage asymmetric waveform at radio frequency combined with a static waveform applied between two electrodes...
DMA differential mobility analyzer: a scanable filter

Types of MS

TOFMS (time-of-flight mass spectrometer)
QMS (quadrupole mass spectrometer)
ITMS (ion trap mass spectrometer)
FTMS (Fourier transform mass spectrometer)
SFMS (sector mass spectrometer)

Applications

The IMS-MS technique can be used for analyzing complex mixtures. It is used in:

proteomics for the analysis of peptides
detection of chemical warfare agents
detection of explosives
analysis of nano particles

External links

Introduction to Mass Spectrometry;
NOT working 7/15/10

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