Sargentini Junior, ÉzioRocha, Julio Cesar [UNESP]Rosa, André Henrique [UNESP]Zara, Luiz Fabricio [UNESP]Santos, Ademir dos [UNESP]2014-05-202014-05-202001-06-01Química Nova. Sociedade Brasileira de Química, v. 24, n. 3, p. 339-344, 2001.0100-4042http://hdl.handle.net/11449/27573The aquatic humic substances (AHS) investigated in this study were conventionally isolated from Rio Negro waters - Amazonas State/Brazil by means of the collector XAD 8. A special five-stage tangential-flow ultrafiltration device was used for analytical fractionation of AHS. The fractionation patterns (6 fractions each) showed that metal traces remaining in AHS after their XAD 8 isolation have different size distributions. For instance, the major percentage of traces of Ni, Cu, Zn, Cd and Pb (determined using ICP-AES) was preferably complexed by molecules with relatively high molecular size (30-100 kDa) and the following complexation order was characterized: F2 >> F1 = F4 = F5 > F3 > F6. Moreover, the species formed between AHS and metals prepared by spiking, showed distribution patterns changing as a function of the complexation time (ageing process), indicating a slow transformation process and an inner rearrangements in the binding sites within the AHS molecules.339-344poraquatic humic substancesfractionationmetal ionsArtigo10.1590/S0100-40422001000300010S0100-40422001000300010Acesso abertoS0100-40422001000300010.pdf41488374036182070000-0002-2042-018X