High-performance liquid chromatography: difference between revisions
Diff·revision 18 → 19·03:51, 26 Mar 2025
Difference between revision 18 and revision 19 of High-performance liquid chromatography. 3 lines changed; the page grew by 647 bytes.
| Revision 18 — 00:44, 6 Mar 2025 ResolutionRoo (talk) clarify that mass spectrometry confirms identity, not purity 5,364 bytes ±0 | Revision 19 — 03:51, 26 Mar 2025 COA_Colwyn (talk) add the ionisation mode to the mass-spectrometry description 6,011 bytes +647 | ||
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| 45 | A short gradient completes quickly and resolves poorly, merging close-eluting impurities into the main peak and returning a higher purity figure. A longer, shallower gradient resolves them and returns a lower one. Both figures are correct for their method. Similarly, detection at 280 nm rather than 214 nm under-detects impurities lacking aromatic residues, and column chemistry alters selectivity as well as retention. | 45 | A short gradient completes quickly and resolves poorly, merging close-eluting impurities into the main peak and returning a higher purity figure. A longer, shallower gradient resolves them and returns a lower one. Both figures are correct for their method. Similarly, detection at 280 nm rather than 214 nm under-detects impurities lacking aromatic residues, and column chemistry alters selectivity as well as retention. |
| 46 | 46 | ||
| + | 47 | This is why a certificate that does not name its column, gradient, flow rate and detection wavelength cannot be compared with any other document or reproduced by any other laboratory. Method transparency is what converts a number into a checkable claim, and it is a more robust criterion for reading a certificate than the value of the number itself. It is also the precondition for the robustness assessment that validation requires. See [[Purity claim inflation]] and [[Analytical method validation]].{{r|usp1503,ich_q2}} | |
| + | 48 | ||
| 47 | == References == | 49 | == References == |
| 48 | {{reflist}} | 50 | {{reflist}} |
| ⋮ | ⋮ | ||
| 50 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> | 52 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> |
| 51 | <ref name="snyder2010">Snyder LR, Kirkland JJ, Dolan JW. ''Introduction to Modern Liquid Chromatography'', 3rd edition (2010).</ref> | 53 | <ref name="snyder2010">Snyder LR, Kirkland JJ, Dolan JW. ''Introduction to Modern Liquid Chromatography'', 3rd edition (2010).</ref> |
| + | 54 | <ref name="ich_q2">International Council for Harmonisation, ''Q2(R2): Validation of Analytical Procedures'' (2023).</ref> | |
| 52 | 55 | ||
| 53 | == See also == | 56 | == See also == |