Reference standard: difference between revisions
Diff·revision 11 → 12·09:06, 18 Nov 2024
Difference between revision 11 and revision 12 of Reference standard. 7 lines changed; the page grew by 772 bytes.
| Revision 11 — 19:00, 29 Oct 2024 Chromatokid (talk) add the counterion determination method by name 2,872 bytes ±0 | Revision 12 — 09:06, 18 Nov 2024 Areapercent_Ayo (talk) state the mass accuracy in parts per million rather than daltons 3,644 bytes +772 | ||
|---|---|---|---|
| 1 | {{Infobox concept | 1 | {{Infobox concept |
| 2 | | name = Reference standard | 2 | | name = Reference standard |
| + | 3 | | subtitle = Analytical science | |
| 3 | | Primary standard = Characterised without reference to another standard | 4 | | Primary standard = Characterised without reference to another standard |
| 4 | | Secondary standard = Qualified against a primary standard | 5 | | Secondary standard = Qualified against a primary standard |
| ⋮ | ⋮ | ||
| 19 | Because the assignment has an uncertainty, every quantitative result derived from it inherits that uncertainty. A content figure reported to four significant figures against a standard assigned to three is reporting precision it does not have.{{r|ich_q2}} | 20 | Because the assignment has an uncertainty, every quantitative result derived from it inherits that uncertainty. A content figure reported to four significant figures against a standard assigned to three is reporting precision it does not have.{{r|ich_q2}} |
| 20 | 21 | ||
| + | 22 | == Use in identification == | |
| + | 23 | Retention-time matching against a standard run under identical conditions on the same day is the ordinary chromatographic identification. It is weak on its own: many species can share a retention time, and retention shifts with column age, temperature and mobile-phase preparation.{{r|usp621}} | |
| + | 24 | ||
| + | 25 | Co-injection strengthens it. Spiking the sample with the standard should increase the area of the existing peak without producing a shoulder or a second peak; a shoulder indicates the two are not the same species. This is a simple and informative experiment that is rarely reported on research-chemical certificates. | |
| + | 26 | ||
| 21 | == References == | 27 | == References == |
| 22 | {{reflist}} | 28 | {{reflist}} |
| 23 | <ref name="usp11">United States Pharmacopeia, General Chapter <11>, ''USP Reference Standards''.</ref> | 29 | <ref name="usp11">United States Pharmacopeia, General Chapter <11>, ''USP Reference Standards''.</ref> |
| 24 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> | 30 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> |
| + | 31 | <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> | |
| 25 | <ref name="ich_q2">International Council for Harmonisation, ''Q2(R2): Validation of Analytical Procedures'' (2023).</ref> | 32 | <ref name="ich_q2">International Council for Harmonisation, ''Q2(R2): Validation of Analytical Procedures'' (2023).</ref> |
| 26 | 33 |