Underfilling: difference between revisions
Diff·revision 2 → 3·20:24, 20 Nov 2024
Difference between revision 2 and revision 3 of Underfilling. 6 lines changed; the page grew by 619 bytes.
| Revision 2 — 04:08, 19 Nov 2024 Chromatokid (talk) add the note that a purity figure without water and counterion is not a mass 1,108 bytes ±0 | Revision 3 — 20:24, 20 Nov 2024 Ref_Desk_Ron (talk) clarify that a QR code on a certificate proves issuance, not content 1,727 bytes +619 | ||
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| 10 | The quantity a purchaser cares about is the mass of peptide in the vial. That is the product of three things — the fill mass, the [[Peptide content|peptide content]] of the solid, and the purity — and a certificate reporting only the last of these constrains it hardly at all.{{r|usp1503}} | 10 | The quantity a purchaser cares about is the mass of peptide in the vial. That is the product of three things — the fill mass, the [[Peptide content|peptide content]] of the solid, and the purity — and a certificate reporting only the last of these constrains it hardly at all.{{r|usp1503}} |
| 11 | 11 | ||
| + | 12 | == Why purity does not detect it == | |
| + | 13 | Chromatographic purity is computed as the area of the main peak divided by the total integrated area, expressed as a percentage. Both terms scale with the amount injected, so the ratio is invariant to concentration over the linear range of the detector.{{r|usp621}} | |
| + | 14 | ||
| + | 15 | A consequence is that a half-filled vial and a correctly filled vial of the same material give the same purity figure. The determination is answering a question about composition, and fill is a question about quantity. | |
| + | 16 | ||
| 12 | == References == | 17 | == References == |
| 13 | {{reflist}} | 18 | {{reflist}} |
| 14 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> | 19 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> |
| + | 20 | <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> | |
| 15 | 21 | ||
| 16 | {{DEFAULTSORT:Underfilling}} | 22 | {{DEFAULTSORT:Underfilling}} |