Counterfeit peptide: difference between revisions
Diff·revision 5 → 6·23:34, 9 Jan 2025
Difference between revision 5 and revision 6 of Counterfeit peptide. 2 lines changed; the page grew by 256 bytes.
| Revision 5 — 13:43, 27 Dec 2024 PrimarySrcPatia (talk) add the laboratory accreditation status, or say plainly that it is not stated 2,066 bytes ±0 | Revision 6 — 23:34, 9 Jan 2025 VerifyFirstVida (talk) clarify that a QR code on a certificate proves issuance, not content 2,322 bytes +256 | ||
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| 11 | The determination that detects substitution is identity — [[Mass spectrometry|mass confirmation]], and where available sequence confirmation — not purity. A substituted compound analysed alone will return an excellent [[Area percent purity|area percent]] figure, because it is a pure sample of whatever it actually is.{{r|usp1503}} | 11 | The determination that detects substitution is identity — [[Mass spectrometry|mass confirmation]], and where available sequence confirmation — not purity. A substituted compound analysed alone will return an excellent [[Area percent purity|area percent]] figure, because it is a pure sample of whatever it actually is.{{r|usp1503}} |
| 12 | 12 | ||
| + | 13 | Dilution is detected by [[Peptide content|content]] rather than by purity, for the same reason underfilling is: a bulking agent that does not absorb at the detection wavelength is invisible to a chromatographic purity determination. See [[Underfilling]]. | |
| + | 14 | ||
| 13 | == Substitution == | 15 | == Substitution == |
| 14 | Substitution replaces the ordered compound with a different one, usually cheaper and often structurally unrelated. Because purity determinations are normalised and identity is frequently not determined, substitution can pass every check a purchaser typically makes.{{r|usp1503}} | 16 | Substitution replaces the ordered compound with a different one, usually cheaper and often structurally unrelated. Because purity determinations are normalised and identity is frequently not determined, substitution can pass every check a purchaser typically makes.{{r|usp1503}} |