Avaliação da radiação gama como agente de imobilização de algumas fases estacionarias sobre suportes para uso em cromatografia gasosa

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

The liquid stationary phases used in gas chromatography present a serious limitation; their volatility and/ or thermal stability which restrict their use to a specified temperature range. In an attempt to minimize this kind of problem, gamma radiation, in different doses, was used to effectuate immobilization of some liquid stationary phases on supports for use in packed column gas chromatography. In addition to thermal stability, other parameters, such as resistance to solvent extraction and chromatographic behavior of the different packing materiais were evaluated. Nonpolar (polymethylsilicone) phases were immobilized with a low radiation dose. The packing materials after irradiation attained greater thermal stability, shown by the small alteration in chromatographic efficiency after heating the column at 100°C above the nominal temperature limit of these liquid phases. The irradiation-produced packing materials were more resistent to solvent extraction, making possible the rinsing of the column with solvents, when necessary to remove contaminants, without removing the stationary phase. Polar phases (polyethylene glycols) showed a different behavior. A satisfatory immobilization of these polymers was possible only by using an irradiation/heating sequence. This process produced columns with greater thermal stability, allowing heating at 100°C above the nominal temperature maximum of this liquid phase. Gamma radiation up to a dose of 250 kGy was an efficient initiator of liquid stationary phase immobilization, producing packing materials resistent to solvent rinsing and with greater thermal stability, without showing alterations in chromatographic behavior.

ASSUNTO(S)

cromatografia gasosa radiação ionizante raios gama

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