Use of the EPR technique to determine thermal stability of some humified organic substances found in soil organic-mineral fractions

Química Nova

Martin-Neto, Ladislau¹  Universidade Estadual de Ponta Grossa, Ponta Grossa¹  Saab, Sérgio da Costa¹  Embrapa Instrumentação Agropecuária, São Carlos¹ 

关键词: semiquinone free radical;    stabilization;    organic matter soil.;   

DOI  :  10.1590/S0100-40422003000400010

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

In this work, using the EPR spectroscopy, we analysed the thermal stability of some organic-mineral compounds found in a Gleysoil from Rio Janeiro. It was observed a complete disappearance of the EPR signal around 600 °C for the < 2 µm fraction and a residual EPR signal of semiquinone free radical for the 2-20 µm and 20-53 µm fractions at the same temperature. Also, the experiments showed that the 2-20 µm fraction had a larger concentration of semiquinone free radical per g of carbon and a smaller line width indicated a larger humification of this fraction. This is an evidence that the soil organic matter of this fraction (2-20 µm) is more stable than the other ones.

【 授权许可】

Unknown