Sorção, imobilização e extração de polissiloxanos em silicas porosas para uso em cromatografia liquida de alta eficiencia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

This work investigated the phenomena responsible for the adsorption and immobilization that occurs between the silica pores and poly(metiloctilsiloxano) (PMOS), used as stationary phase in High Performance Liquid Chromatography (HPLC) in the reversed phase. Through kinetic, spectroscopic and chromatographic studies, was verified that, after preparation of the stationary phase, immobilization of the liquid phase into support occurs without the use of cross-linking agents. This process, that is slow at room temperature, was labeled self-immobilization, and involves rearrangement of the polymer chains, reaching a uniform configuration of a monolayer immobilized on the pore walls. It was also shown that the use of a thermal treatment, after the preparation of the stationary phases, can accelerate the process of self-immobilization that occurs at room temperature, producing phases with polymer thicknesses of a monolayer (temperatures up to 120 °C) or bilayer (temperatures starting at 150 °C). Modification of the silica surface by hydrophobic groups was also explored, turning the surface less polar and the silanols groups less actives. With this modification, PMOS had less interaction with the silica and the chromatographic parameters were not improved, when compared with bare silica. The results obtained suggest that the adsorption of PMOS onto silica occurs through many physisorption contacts, giving a quite stable configuration that is immobilization.

ASSUNTO(S)

silica cromatografia liquida de alta eficiencia

ACESSO AO ARTIGO

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