Karl Fischer titration: difference between revisions
Diff·revision 13 → 14·07:43, 27 Aug 2024
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| Revision 13 — 18:43, 20 Aug 2024 CarryOverCai (talk) attribute range as a review estimate per talk 2,813 bytes +314 | Revision 14 — 07:43, 27 Aug 2024 INN_Ingrid (talk) expand §Chemical basis 3,604 bytes +791 | ||
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| 21 | Two features follow from the stoichiometry and are the practical basis of the method: | 21 | Two features follow from the stoichiometry and are the practical basis of the method: |
| 22 | 22 | ||
| + | 23 | == Volumetric and coulometric variants == | |
| + | 24 | | Property | Volumetric | Coulometric | | |
| + | 25 | |---|---|---| | |
| + | 26 | | Iodine source | Titrant from burette | Generated at anode | | |
| + | 27 | | Water range | 1–500 mg | 10 µg – 10 mg | | |
| + | 28 | | Titrant standardisation | Required, daily | Not required | | |
| + | 29 | | Typical sample | 100 mg – 1 g | 10–100 mg | | |
| + | 30 | | Suits lyophilised peptides | Marginally | Yes | | |
| + | 31 | | Cell volume | 30–50 mL | 100–150 mL | | |
| + | 32 | ||
| + | 33 | For a research peptide vial nominally containing 5–10 mg of solid, only the coulometric variant is realistic: the total water present may be as little as 300 µg, which is below the practical resolution of a volumetric titration on that sample mass. Certificates reporting water content on 10 mg vials by volumetric titration should be read with that in mind.{{r|scholz1984}} | |
| + | 34 | ||
| 23 | == References == | 35 | == References == |
| 24 | {{reflist}} | 36 | {{reflist}} |