| Popis: |
Polymeric monoliths of different polymeric natures and different degrees of cross-linking were prepared in capillaries of inner diameter 100 microm. The properties of the monoliths prepared were investigated by means of inverse gas chromatography. Solubility coefficient S, Flory-Huggins parameter chi(12)(infinity), and reduced Flory-Huggins parameter chi(12)(infinity') were evaluated. The solubility parameter S of all samples depends on the degree of cross-linking of the monoliths, which is characterized by the reduced Flory-Huggins parameter chi(12)(infinity'). A linear dependence of the logarithm of the solubility parameter S on the solute critical temperature was also demonstrated, as it is well known for non-cross linked polymers. The diffusivity of low molecular mass solutes in monoliths was evaluated by calculation of the ratio D/d(f)(2), and a maximum was detected for the dependence of the ratio D/d(f)(2) on the degree of cross-linking of monoliths. Correlation of the measured monolith properties with the separation performance of capillary columns was carried out and revealed that the best performance in GC is provided by monolithic columns prepared from purely bifunctional monomer, i. e. having 100% cross-linking. |
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