Peptide content: difference between revisions
Diff·revision 13 → 14·08:51, 9 Mar 2025
Difference between revision 13 and revision 14 of Peptide content. 2 lines changed; the page grew by 469 bytes.
| Revision 13 — 19:27, 21 Feb 2025 DiluentDiya (talk) add the equilibration time to the gradient description 6,078 bytes +1,146 | Revision 14 — 08:51, 9 Mar 2025 GradientGus (talk) add the sample preparation, since the result depends on it 6,547 bytes +469 | ||
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| 49 | The peptide mass present is 5 mg × 0.82 = 4.1 mg. The concentration is therefore 4.1 mg ÷ 2 mL = 2.05 mg/mL, not the 2.5 mg/mL that the nominal label alone would give — a difference of 18%. | 49 | The peptide mass present is 5 mg × 0.82 = 4.1 mg. The concentration is therefore 4.1 mg ÷ 2 mL = 2.05 mg/mL, not the 2.5 mg/mL that the nominal label alone would give — a difference of 18%. |
| 50 | 50 | ||
| + | 51 | Both statements are true of the same vial. Which one a purchaser needs depends on what the nominal fill was specified to mean, and the honest position is that on unregulated material this is frequently not specified at all: a "5 mg" vial may be filled to 5 mg of gross solid or to 5 mg of peptide, and the two differ by exactly the content figure. '''Where a certificate reports content, it is worth asking which convention the fill statement follows.'''{{r|usp1503}} | |
| + | 52 | ||
| 51 | == References == | 53 | == References == |
| 52 | {{reflist}} | 54 | {{reflist}} |