In
mass spectrometry, a matrix is a compound that promotes the formation of
ion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s. Matrix compounds are used in
matrix-assisted laser desorption/ionization
In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of ...
(MALDI),
matrix-assisted ionization (MAI), and
fast atom bombardment
Fast atom bombardment (FAB) is an ionization technique used in mass spectrometry in which a beam of high energy atoms strikes a surface to create ions. It was developed by Michael Barber at the University of Manchester in 1980. When a beam of hig ...
(FAB).
Matrix-assisted laser desorption/ionization
MALDI is an
ionization
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecul ...
technique where laser energy is absorbed by a matrix to create
ion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s from large
molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...
s without fragmentation. The matrix, typically in excess, is mixed with the analyze molecule and deposited on a target. A table of matrix compounds, their structures, laser wavelengths typically used, and typical application is shown below.
Matrix-assisted ionization
Matrix-assisted ionization is an ionization method in mass spectrometry that creates ions via the creation of particles at
atmospheric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, ...
and transfer to the vacuum of the
mass analyzer.
Fast atom bombardment
FAB uses a high energy beam of
atoms directed at a surface to create ions.
FAB matrix compounds are typically liquids.
See also
*
Desorption/ionization on silicon
References
{{Mass spectrometry
Mass spectrometry