Estudo do transporte passivo facilitado de acido ascorbico atraves de membrana liquida hidrofobica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

In this work a physical chemical study of the transport of Ascorbic Acid (cis-a, b diol compound) through a hydrophobic liquid membrane (1,2-Diclhoroethane) carried by Phenylboronic acid was done by using a BLM (Bulk liquid membrane) conected to a continuous flow circuit. Initially the transport process was difficult to study due to the fast oxidation of the Ascorbic Acid in aqueous solution, but this difficulty was overcomed by adding reduced Glutathione to the solution. The influence of the source phase concentration, temperature and the carrier on the transport of Ascorbic Acid through the hydrophobic membrane were also studied. With the increasing of the Ascorbic Acid concentration on the source phase an almost linear behavior of concentration against time was observed for this compound in the receiving phase. An increase on the transport rate was promoted by increasing the temperature. The effect of the carrier on the transport became distinct because in the absence of this molecule none significant transport through the hydrophobic membrane was observed. By using UV-Vis spectrophotometry, the kinetics of the Ascorbic Acid transport was studied in real time and the results were obtained using multivariate methods (PLS). The chemical interaction between Ascorbic Acid and Phenylboronic Acid was studied by RMN of H and C and the results are explicit showing that this interaction does not occurs on the ring diol group of the Ascorbic Acid molecule. Theoretical calculations were performed to estimate the relative stability between the two molecular structure which can be formed in the hydrophobic membrane during the transport. The results are in agreement with the RMN data.

ASSUNTO(S)

membranas permeaveis a ions vitamina c transporte biologico

ACESSO AO ARTIGO

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