Mass spectrometry: difference between revisions
Diff·revision 14 → 15·21:24, 15 Dec 2024
Difference between revision 14 and revision 15 of Mass spectrometry. 2 lines changed; the page grew by 283 bytes.
| Revision 14 — 13:14, 23 Nov 2024 ColumnOvenCoy (talk) ce, tighten prose 4,018 bytes +137 | Revision 15 — 21:24, 15 Dec 2024 AnalyticalAnnie (talk) add category for method validation 4,301 bytes +283 | ||
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| 32 | Intact-mass agreement is a strong but incomplete identification. Two different sequences composed of the same residues have identical masses, and inverting the order of two residues changes nothing about the intact mass. Only fragmentation — tandem mass spectrometry, which selects a precursor ion, breaks it and measures the fragments — addresses sequence order.{{r|aebersold2003}} | 32 | Intact-mass agreement is a strong but incomplete identification. Two different sequences composed of the same residues have identical masses, and inverting the order of two residues changes nothing about the intact mass. Only fragmentation — tandem mass spectrometry, which selects a precursor ion, breaks it and measures the fragments — addresses sequence order.{{r|aebersold2003}} |
| 33 | 33 | ||
| + | 34 | Stereochemistry is invisible to mass spectrometry entirely. A D-amino acid substitution is isobaric with the L form and requires [[Amino acid analysis|chiral analysis]] to detect. For peptides synthesised with racemisation-prone residues this is a real rather than theoretical gap. | |
| + | 35 | ||
| 34 | == References == | 36 | == References == |
| 35 | {{reflist}} | 37 | {{reflist}} |