Underfilling: difference between revisions
Diff·revision 11 → 12·04:20, 27 Mar 2025
Difference between revision 11 and revision 12 of Underfilling. 17 lines changed; the page grew by 878 bytes.
| Revision 11 — 18:24, 7 Mar 2025 EndotoxinEd (talk) state the method the reporting service uses, since it is not the only one available 2,520 bytes ±0 | Revision 12 — 04:20, 27 Mar 2025 CiteBot (talk) bot: flag bare reference 3,398 bytes +878 | ||
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| 22 | The same reasoning applies to identity determinations. A [[Mass spectrometry|mass spectrum]] confirms what a molecule is, not how much of it there is, unless the method is explicitly quantitative against a standard. | 22 | The same reasoning applies to identity determinations. A [[Mass spectrometry|mass spectrum]] confirms what a molecule is, not how much of it there is, unless the method is explicitly quantitative against a standard. |
| 23 | 23 | ||
| + | 24 | == What does detect it == | |
| + | 25 | | Determination | What it gives | | |
| + | 26 | |---|---| | |
| + | 27 | | Gravimetric fill check | Mass of solid in the vial | | |
| + | 28 | | [[Peptide content]] | Fraction of that solid that is peptide | | |
| + | 29 | | Water by [[Karl Fischer titration]] | Fraction that is water | | |
| + | 30 | | Counterion content | Fraction that is salt | | |
| + | 31 | | Quantitative assay against a standard | Peptide mass directly | | |
| + | 32 | ||
| + | 33 | The arithmetic that matters is straightforward. A vial containing 5.0 mg of solid at 80% peptide content contains 4.0 mg of peptide, whatever its purity figure says; the same vial at 60% content contains 3.0 mg. Content in the 70–90% range is ordinary for a [[Trifluoroacetate counterion|trifluoroacetate-salted]] lyophilisate, and figures below that are not rare.{{r|usp1503}} | |
| + | 34 | ||
| 24 | == References == | 35 | == References == |
| 25 | {{reflist}} | 36 | {{reflist}} |
| ⋮ | ⋮ | ||
| 27 | <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> | 38 | <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> |
| 28 | <ref name="reports">PeptidePedia Wiki community test-report tally, 2024–2026 (self-reported; see [[Project:Sourcing_guidelines]]).</ref> | 39 | <ref name="reports">PeptidePedia Wiki community test-report tally, 2024–2026 (self-reported; see [[Project:Sourcing_guidelines]]).</ref> |
| + | 40 | ||
| + | 41 | == See also == | |
| + | 42 | * [[Peptide content]] | |
| + | 43 | * [[Area percent purity]] | |
| + | 44 | * [[Vial filling and stoppering]] | |
| + | 45 | * [[Certificate of analysis]] | |
| 29 | 46 | ||
| 30 | {{DEFAULTSORT:Underfilling}} | 47 | {{DEFAULTSORT:Underfilling}} |