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| Rossete,Alexssandra Luiza Rodrigues Molina; Carneiro,Josiane Meire Toloti; Sant Ana Filho,Carlos Roberto; Bendassolli,José Albertino. |
| Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S) with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS) in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-)), which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2-) concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sample preparation; Soil samples; Isotopic dilution; Labeled material; Stable isotope; 34S. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000600012 |
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| Rossete,Alexssandra Luiza Rodrigues Molina; Bendassolli,José Albertino; Máximo,Everaldo; Sant Ana Filho,Carlos Roberto; Ignoto,Raquel de Fátima de. |
| Agricultural gypsum (CaSO4.2H2O) stands out as an effective source of calcium and sulfur, and to control aluminum saturation in the soil. Labeled as 34S it can elucidate important aspects of the sulfur cycle. Ca34SO4.2H2O was obtained by chemical reaction between Ca(OH)2 and H2(34)SO4, performed under slow agitation. The acid was produced by ion exchange chromatography using the Dowex 50WX8 cation exchange resin and a Na2(34)SO4 eluting solution. After precipitation, the precipitate was separated and dried in a ventilated oven at 60ºC. From 2.2 L H2SO4 0.2 mol L-1 and 33.6 g Ca(OH)2, 73.7 ± 0.6 g Ca34SO4.2H2O were produced on average in the tests, representing a mean yield of 94.6 ± 0.8%, with 98% purity. The 34SO2 gas was obtained from Ca34SO4.2H2O in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sulfur 34; Stable isotope; Isotopic determination. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000400012 |
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