CLASSIFICATION OF BINDING-SITES FOR AL(III) IN FULVIC-ACIDS EXTRACTEDFROM LEAF LITTERS AND SOILS BY SYNCHRONOUS FLUORESCENCE SPECTROSCOPY AND MULTIDIMENSIONAL CHEMOMETRIC ANALYSIS
Jcge. Dasilva et al., CLASSIFICATION OF BINDING-SITES FOR AL(III) IN FULVIC-ACIDS EXTRACTEDFROM LEAF LITTERS AND SOILS BY SYNCHRONOUS FLUORESCENCE SPECTROSCOPY AND MULTIDIMENSIONAL CHEMOMETRIC ANALYSIS, Analytica chimica acta, 333(1-2), 1996, pp. 71-82
The major binding sites for Al(III) in six samples of fulvic acids (fu
a) extracted form soils and leaf litters were investigated by synchron
ous fluorescence (SyF) spectroscopy. Two samples of fua from soil of a
n oak forest (two horizons, 0-5 cm, fuaol, and 5-15 cm, fuao2) and fou
r fua like samples extracted from leaf litters (eucalyptus, fern, oak
and chestnut coverture, respectively feu, fer, foa and fch) were studi
ed. The SyF spectra of the mixtures of fua and increasing concentratio
n of Al(III), at pH 4, were analyzed by evolving factor analysis (EFA)
, a self-modeling curve resolution method, to detect the number of maj
or binding sites, their SyF spectra and SyF profiles as function of th
e AI(III) concentration. The overall set of calculated SyF spectra was
analyzed by pattern recognition methods, such as cluster analysis and
multidimensional scaling, to detect similarities and differences betw
een them. Although there are differences in the intrinsic SyF properti
es of fua extracted from soils and leaf litters, the soil fua samples
showing a more complex binding site composition, the most important bi
nding site is common to all fua samples studied. The amount of this bi
nding site was roughly estimated. It is approximately the same for all
samples but for fuao2, in which the amount is twice the others.