Loss on drying: difference between revisions
Diff·revision 3 → 4·08:20, 7 Sep 2024
Difference between revision 3 and revision 4 of Loss on drying. 5 lines changed; the page grew by 534 bytes.
| Revision 3 — 21:44, 30 Aug 2024 MolarMassMaeve (talk) state the titration endpoint and the reagent factor 1,231 bytes ±0 | Revision 4 — 08:20, 7 Sep 2024 SigFigSindri (talk) British spelling per PP:MOS 1,765 bytes +534 | ||
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| 11 | It is not a water determination. The mass lost comprises water and any other volatile component — residual acetonitrile, acetic acid, ammonia from a salt-exchange step — so a loss-on-drying figure is an upper bound on water content rather than a measurement of it. [[Karl Fischer titration|Karl Fischer titration]] measures water specifically and will generally give a lower number on the same material.{{r|usp921}} | 11 | It is not a water determination. The mass lost comprises water and any other volatile component — residual acetonitrile, acetic acid, ammonia from a salt-exchange step — so a loss-on-drying figure is an upper bound on water content rather than a measurement of it. [[Karl Fischer titration|Karl Fischer titration]] measures water specifically and will generally give a lower number on the same material.{{r|usp921}} |
| 12 | 12 | ||
| + | 13 | == Method == | |
| + | 14 | A weighed sample is dried to constant mass under stated conditions — an oven at a specified temperature, or a desiccator over a specified desiccant, or under vacuum — and the mass difference expressed as a percentage of the starting mass.{{r|usp731}} | |
| + | 15 | ||
| + | 16 | The conditions are part of the result. Drying at 105 °C removes more than drying at 60 °C; drying under vacuum removes more than at atmospheric pressure. A figure quoted without its conditions is not comparable with another figure quoted without its conditions. | |
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| 13 | == References == | 18 | == References == |
| 14 | {{reflist}} | 19 | {{reflist}} |