Karl Fischer titration: difference between revisions
Diff·revision 18 → 19·17:12, 29 Sep 2024
Difference between revision 18 and revision 19 of Karl Fischer titration. 4 lines changed; the page grew by 308 bytes.
| Revision 18 — 20:29, 21 Sep 2024 NewLabNell (talk) replace bare ref with full citation 4,173 bytes ±0 | Revision 19 — 17:12, 29 Sep 2024 PreregPriya (talk) label community tally as self-reported 4,481 bytes +308 | ||
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| 1 | {{Infobox method | 1 | {{Infobox method |
| 2 | | name = Karl Fischer titration | 2 | | name = Karl Fischer titration |
| + | 3 | | image = coa-sheet.svg | |
| + | 4 | | caption = Water content appears on a certificate of analysis alongside purity and peptide content. | |
| 3 | | Measures = Water (moisture) content | 5 | | Measures = Water (moisture) content |
| 4 | | Classification = Titrimetric, iodine-based | 6 | | Classification = Titrimetric, iodine-based |
| ⋮ | ⋮ | ||
| 28 | * the endpoint is detectable amperometrically, because excess iodine depolarises a double-platinum indicator electrode; | 30 | * the endpoint is detectable amperometrically, because excess iodine depolarises a double-platinum indicator electrode; |
| 29 | * one faraday of charge liberates one mole of iodine, so in the coulometric variant the ''charge passed'' is a direct measure of water — no titrant standardisation is required. | 31 | * one faraday of charge liberates one mole of iodine, so in the coulometric variant the ''charge passed'' is a direct measure of water — no titrant standardisation is required. |
| + | 32 | ||
| + | 33 | Away from the buffered pH window the stoichiometry drifts, which is the reason strongly acidic or basic samples require a modified reagent rather than a correction factor. | |
| 30 | 34 | ||
| 31 | == Volumetric and coulometric variants == | 35 | == Volumetric and coulometric variants == |