Karl Fischer titration: difference between revisions
Diff·revision 14 → 15·04:38, 2 Sep 2024
Difference between revision 14 and revision 15 of Karl Fischer titration. 8 lines changed; the page grew by 532 bytes.
| Revision 14 — 07:43, 27 Aug 2024 INN_Ingrid (talk) expand §Chemical basis 3,604 bytes +791 | Revision 15 — 04:38, 2 Sep 2024 AnalyticalAnnie (talk) convert list to prose 4,136 bytes +532 | ||
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| 4 | | Classification = Titrimetric, iodine-based | 4 | | Classification = Titrimetric, iodine-based |
| 5 | | Variants = Volumetric; coulometric | 5 | | Variants = Volumetric; coulometric |
| + | 6 | <!-- Performance --> | |
| + | 7 | | Typical range (coulometric) = 10 µg – 10 mg water | |
| + | 8 | | Typical range (volumetric) = 1 mg – 500 mg water | |
| + | 9 | | Reported precision = ≈1–3% relative at 1–10% w/w | |
| + | 10 | | Sample size = 10–100 mg lyophilised solid | |
| 6 | }} | 11 | }} |
| 7 | 12 | ||
| ⋮ | ⋮ | ||
| 20 | 25 | ||
| 21 | Two features follow from the stoichiometry and are the practical basis of the method: | 26 | Two features follow from the stoichiometry and are the practical basis of the method: |
| + | 27 | ||
| + | 28 | * 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. | |
| 22 | 30 | ||
| 23 | == Volumetric and coulometric variants == | 31 | == Volumetric and coulometric variants == |