In this work have been realized the extration of húmic substances (SH) proceeding from the peat collected to the edges of the river Mogi-Guaçu, according to described methodology for Rosa et al., 2000. The SH had been fractions in an equipment of ultrafiltration in three molecular sizes: between molecular sizes 30 -100 KDa, less than 30 KDa molecular sizes and more than 100 KDa. The fractions had been characterized by different analytical techniques such electron paramagnetic resonance (EPR), infrared spectroscopy, elemental analysis and spectroscopy in the region visible (UV/Vis). It was verified that the fractions of lesser molar mass between 30 - 100 KDa molecular sizes and less than molecular sizes presented a bigger on molecule number with oxygen while that the fraction of bigger molar mass more than100 KDa molecular sizes presented a bigger number aromatical molecules. Through the results of the elementary analyses and eletronic paramagnetic resonance, the fraction evidenced less than 30 KDa showing smaller percentagens of carbon, nitrogen and hydrogen and a smaller amount of free radicals in relation to the othess, indicating that this fraction possess a smaller number of conjugated aromatical rings. Already in the analyses for IV characteristic bands of the SH had been observed.
humics substances; characterizations; peat
