Matrix (mass spectrometry)
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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).
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.
| 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]
| Compound | Abbreviation | Structure |
|---|---|---|
| 2,5-dihydroxybenzoic acid | DHB | |
| 2-aminobenzyl alcohol | ||
| anthranilic acid | ||
| 2-hydroxyacetophenone |