0000000000528385
AUTHOR
G. Stegeman
The application of porous silica layers in open tubular columns for liquid chromatography
Two methods to realize a porous retentive silica layer on the inner wall of 10–25 µm fused silica capillaries for OTLC, etching and precipitation of silica from solution, have been investigated. Etching of the fused silica capillaries with 1M KOH, creates an activated surface, but the capacity of the silica layer is too small to serve as retentive layer in OTLC. Better prospects are offered by the precipitation of silica from a solution of polyethoxysiloxane, dynamically coated on the inner wall of the fused silica capillary. It appears to be possible to deposite a porous silica layer up to 0.8 µm thick (in a 25 µm capillary) by this method, which seems to be suitable for liquid-solid an dy…
Hydrodynamic chromatography of macromolecules on small spherical non-porous silica particles
Abstract Non-porous silica spheres with sizes in the range 1.4–2.7 μm were applied as packings for the hydrodynamic chromatography (HDC) of macromolecules. Highly efficient columns, with a reduced plate height below 2, were packed with these small particles. Up to molecular weights of 10 6 the elution behaviour of polystyrenes agreed very well with existing theoretical models. However, for larger polystyrenes the flow-rate exerted an influence on the relative peak positions. The applicability of HDC to rapid separations of soluble macromolecules and inorganic colloids was demonstrated.