Mass Spectrometry
Principle and Application
Introduction
Mass spectrometry's characteristics have raised it to an outstanding position
among analytical methods: unequaled sensitivity, detection limits, speed, and
diversity of its applications. In analytical chemistry, the most recent applications
are mostly oriented towards bio- chemical problems, such as proteome,
metabolome, high throughput in drug discovery and metabolism, and so on.
Other analytical applications are routinely applied in pollution control, food
control, forensic science, natural products, or process monitoring. Other
applications include atomic physics, reaction physics, reaction kinetics,
geochronology, inorganic chemical analysis, ion-molecule reactions,
determination of thermodynamic pa- rameters (ΔG°f, Ka , etc.), and many others.
What is Mass Spectrometry?
Mass spectrometry is an analytical method useful for calculating the mass-to-
charge ratio (m / z) of one or more molecules in the sample. Such measurements
may also often be used to determine the precise molecular weight of the sample
components. Mass spectrometry is an analytical method to find the molecular
mass of a compound and indirectly helps to prove the identity of isotopes.
Principles
The first step in the mass spectrometric analysis of compounds is the production
of gas-phase ions of the compound, for example by electron ionization:
M + e- M+ + 2e-
This molecular ion normally undergoes fragmentations. Because it is a radical
cation with an odd number of electrons, it can fragment to give either a radical
and an ion with an even number of electrons, or a molecule and a new radical
cation. We stress the important difference between these two types of ions and
the need to write them correctly:
Principle and Application
Introduction
Mass spectrometry's characteristics have raised it to an outstanding position
among analytical methods: unequaled sensitivity, detection limits, speed, and
diversity of its applications. In analytical chemistry, the most recent applications
are mostly oriented towards bio- chemical problems, such as proteome,
metabolome, high throughput in drug discovery and metabolism, and so on.
Other analytical applications are routinely applied in pollution control, food
control, forensic science, natural products, or process monitoring. Other
applications include atomic physics, reaction physics, reaction kinetics,
geochronology, inorganic chemical analysis, ion-molecule reactions,
determination of thermodynamic pa- rameters (ΔG°f, Ka , etc.), and many others.
What is Mass Spectrometry?
Mass spectrometry is an analytical method useful for calculating the mass-to-
charge ratio (m / z) of one or more molecules in the sample. Such measurements
may also often be used to determine the precise molecular weight of the sample
components. Mass spectrometry is an analytical method to find the molecular
mass of a compound and indirectly helps to prove the identity of isotopes.
Principles
The first step in the mass spectrometric analysis of compounds is the production
of gas-phase ions of the compound, for example by electron ionization:
M + e- M+ + 2e-
This molecular ion normally undergoes fragmentations. Because it is a radical
cation with an odd number of electrons, it can fragment to give either a radical
and an ion with an even number of electrons, or a molecule and a new radical
cation. We stress the important difference between these two types of ions and
the need to write them correctly:
