Peptide content: difference between revisions
Diff·revision 7 → 8·16:16, 20 Nov 2024
Difference between revision 7 and revision 8 of Peptide content. 4 lines changed; the page grew by 429 bytes.
| Revision 7 — 09:28, 4 Nov 2024 Chromatokid (talk) fix a broken wikilink 3,523 bytes +32 | Revision 8 — 16:16, 20 Nov 2024 NauseaNoor (talk) add category for method validation 3,952 bytes +429 | ||
|---|---|---|---|
| 1 | {{Infobox method | 1 | {{Infobox method |
| 2 | | name = Peptide content | 2 | | name = Peptide content |
| + | 3 | | image = titration.svg | |
| + | 4 | | caption = Content is a mass balance: what is in the vial that is not peptide has to be measured before what is can be stated. | |
| 3 | <!-- Definition --> | 5 | <!-- Definition --> |
| 4 | | Quantity = Mass of peptide ÷ mass of preparation | 6 | | Quantity = Mass of peptide ÷ mass of preparation |
| ⋮ | ⋮ | ||
| 26 | 28 | ||
| 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}} | 29 | 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}} |
| + | 30 | ||
| + | 31 | Water is the term that varies most between vials of the same lot, because a lyophilised cake takes up moisture from the atmosphere on any exposure. That is what the desiccant sachet in a well-packed consignment is for, and it is why a content figure carries a date. | |
| 28 | 32 | ||
| 29 | == References == | 33 | == References == |