Matrix (mass spectrometry)

This article is about ionization assisting compounds for mass spectrometry. For the non-analyte components of a sample, see matrix (chemical analysis).

In mass spectrometry, a matrix is a compound that promotes the formation of ions. Matrix compounds are used in matrix-assisted laser desorption/ionization (MALDI), matrix-assisted ionization (MAI), and fast atom bombardment (FAB).

Matrix-assisted laser desorption/ionization

MALDI is an ionization technique where laser energy is absorbed by a matrix to create ions from large molecules without fragmentation. The matrix, typically in excess, is mixed with the analyte molecule and deposited on a target. A table of matrix compounds, their structures, laser wavelengths typically used, and typical application is shown below.

MALDI Matrix List

Compound	Abbreviation	Structure	Wavelength (nm)	Applications
9-aminoacridine[1]	9AA		337	lipids, metabolites
α-cyano-4-hydroxycinnamic acid[2]	CHCA		337, 355	peptides, lipids, nucleotides
ferulic acid[3][4]	FA		337, 355, 266	proteins
2,5-dihydroxy benzoic acid|[5]	DHB		337, 355	peptides, nucleotides, oligonucleotides, oligosaccharides
3-hydroxy picolinic acid[6]	HPA		337, 355	oligonucleotides
picolinic acid[7]	PA		266	oligonucleotides
sinapinic acid[3][4]	SA		337, 355, 266	peptides, proteins, lipids

Matrix-assisted ionization

Matrix-assisted ionization is an ionization method in mass spectrometry that creates ions via the creation of particles at atmospheric pressure and transfer to the vacuum of the mass analyzer.^[8]

List of Matrix-assisted Ionization Compounds^[9]

Compound	Abbreviation	Structure
2,5-dihydroxybenzoic acid	DHB
2-aminobenzyl alcohol
anthranilic acid
2-hydroxyacetophenone

Fast atom bombardment

FAB uses a high energy beam of atoms directed at a surface to create ions.^[10] FAB matrix compounds are typically liquids.

FAB Matrix List

Compound	Abbreviation	Structure
glycerol
thioglycerol
3-nitrobenzyl alcohol	NBA
18-crown-6 ether
2-nitrophenyloctyl ether	NPOE
diethanolamine
triethanolamine

See also

• Desorption/ionization on silicon