Isotope determination of sulfur by mass spectrometry in soil samples

Revista Brasileira de Ciência do Solo

Alexssandra Luiza Rodrigues Molina Rossete²  Josiane Meire Toloti Carneiro²  Carlos Roberto Sant Ana Filho²  José Albertino Bendassolli¹ 

[1] ,USP Centro de Energia Nuclear na Agricultura Piracicaba SP ,Brazil

关键词: sample preparation;    soil samples;    isotopic dilution;    labeled material;    stable isotope;    34S;    preparo de amostras;    amostras de solo;    diluição isotópica;    isótopos estáveis;    34S;   

DOI  :  10.1590/S0100-06832012000600012

来源: SciELO

【 摘 要 】

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 determination of S (atom % 34S atoms) was carried out by isotope ratio mass spectrometry (IRMS). In this work, the labeled material (K2(34)SO4) was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.

【 授权许可】

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