INFLUENCE OF DENSITY OF ZEOLITE PARTICLES ON THEIR RETENTION IN GRAVITATIONAL FIELD-FLOW FRACTIONATION

Gravitational force is one of main forces necessary for separation of particles in gravitational field-flow fractionation. It is proportiona l to particle size and density. The influence of density on the elutio n behavior was studied using zeolites containing varying amounts of pl atinum. The other properties of the zeolite samples (e.g., size, shape , particle size distribution) were the same as those of the original z eolite sample without platinum. We proved that retention of particles was related to their densities. However, densities could not be calcul ated from elution data because we found that zeolites were eluted in a focusing elution mode. This mode was induced by hydrodynamic lift-for ces and their nature has not been fully understood yet; this excludes exact calculation of density. The effects of sample preparation, amoun ts of sample injected, and flow rates of a carrier liquid are describe d.