Data/hora: 20/06/2024 01:57:01

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 13/08/2004
Data da última atualização: | 01/03/2010
Autoria: | GALETI, H. V. A.; MILORI, D. M. B. P.; CUNHA, T. J. F.; MARTIN-NETO, L.; MADARI, B.; BENITES, V. de M.; SANTOS, G. de A.
Título: | Analysis of concentration effect on laser-induced fluorescece of humic acids in solid samples.
Ano de publicação: | 2004
Fonte/Imprenta: | In: MARTIN-NETO, L.; MILORI, D.M.B.P.; SILVA, W.T.L. (Ed.). Humic substances and soil and water environment: International Meeting of IHSS, 12. São Carlos : Embrapa Instrumentação Agropecuária, 2004. p. 332-334.
Idioma: | Inglês
Notas: | CLASSIFICAÇÃO CDD: 630

Conteúdo:

I. INTRODUCTION 
Soil organic matter (SOM) is constituted of, basically, two types of substances: humic (humic acid (HA), fulvic acid (FA) and humin (H)) and non humic (proteins, amino acids, polysaccharides, organic acid of low molecular weight, waxes and others). The humic substances (HS) are the most recalcitrant components of soil organic matter, and they are constituted of an heterogeneous mixture of functional groups. These are formed during the humification process, which modilies chemical structures of OM through the degradation of organic residues, being controlled through variables such as temperature, soil water regime, pH and free nutrients. The study of SOM, in particular of the 
HS, has shown necessary and very important to understand mechanisms of its formation and stabilization. Its characterization is relevant because it has a function in the productivity and structure of soil. 
Spectroscopic techniques which make possible studies of OM near natural situation are interesting, mainly if they work with low negative interference of intrinsic components of this material, such as metals. In this direction, a new technique has being applied: Laser-lnduced Fluorescence (LIF) spectroscopy. This technique presents, in recent and preliminary results, an indicative of high potential to evaluate humification degree of OM in whole soil through a relatively simple methodology. 
However, physical and chemical parameters generate effects that inlluence the LIF. These , effects are not known yet, as well as the parameters which generate them. The concentration is a parameter that affects the LIF intensity, and can easily be controlled in laboratory. The goal of this work is to understand the dependence of soil HA fluorescence as a function of concentration, to evaluate which range of organic matter concentration the methodology can be applied.

Palavras-Chave: | fluorescence spectroscopy; laser.
Thesaurus Nal: | humic substances; soil organic matter.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (8338-1) - UMT - SP - -- - PROCI-04.00005 -  - 2004.00005 - DIS