Sôbre a determinação do nitrogênio, do fósforo e do potássio no mesmo extrato
The determination of total nitrogen, phosphorus, and potassium in plant material can be carried out in a common extract prepared with sulphuric acid and 30 per cent hydrogen peroxide. Nitrogen is estimated by direct nesslerization of a suitable aliquot (1-5 ml of the 50 ml extract made out of 250 mg of dried material); in order to avoid excessive acidity, 10 ml of Nessler's reagent should be employed. An aliquot of 1-5 ml suffices for the colorimetric determination of phosphorus by the molybdenum method; to reduce the phosphomolybdate complex 2 ml of a 2% SnC12 soln are necessary. Potassium is determined by the cobaltinitrite method after elimination of ammonium salts with the aid of aqua-regia.
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| Principais autores: | , , |
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| Formato: | Digital revista |
| Idioma: | Portuguese |
| Publicado em: |
Universidade de São Paulo
1958
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| Acesso em linha: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761958000100002 |
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