Peptide content: difference between revisions
Diff·revision 5 → 6·18:51, 25 Oct 2024
Difference between revision 5 and revision 6 of Peptide content. 6 lines changed; the page grew by 537 bytes.
| Revision 5 — 18:31, 6 Oct 2024 FigureFerdinand (talk) add the ionisation mode to the mass-spectrometry description 2,954 bytes +425 | Revision 6 — 18:51, 25 Oct 2024 PeakShapePol (talk) convert the method-comparison paragraph to a table 3,491 bytes +537 | ||
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| 1 | {{Infobox method | 1 | {{Infobox method |
| 2 | | name = Peptide content | 2 | | name = Peptide content |
| + | 3 | <!-- Definition --> | |
| + | 4 | | Quantity = Mass of peptide ÷ mass of preparation | |
| + | 5 | | Units = Per cent by mass | |
| + | 6 | | Typical range = 70–90% for a lyophilised trifluoroacetate salt | |
| 3 | }} | 7 | }} |
| 4 | 8 | ||
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| 20 | 24 | ||
| 21 | The acetonitrile carried over from preparative purification is the residual solvent that dominates in practice; it is classified for toxicity and given a concentration limit under the harmonised residual-solvent guideline, and it is determined by headspace gas chromatography rather than inferred.{{r|ichq3c}} | 25 | The acetonitrile carried over from preparative purification is the residual solvent that dominates in practice; it is classified for toxicity and given a concentration limit under the harmonised residual-solvent guideline, and it is determined by headspace gas chromatography rather than inferred.{{r|ichq3c}} |
| + | 26 | ||
| + | 27 | The counterion share is the term that surprises people. Trifluoroacetic acid is used in the mobile phase of the purification, and a basic peptide leaves that step as its trifluoroacetate salt with one counterion per basic site. For a peptide with several basic residues and a modest molecular mass, the counterion can be a fifth of the dry weight.{{r|usp1503}} | |
| 22 | 28 | ||
| 23 | == References == | 29 | == References == |