The Performance of Packings in High Speed Liquid Chromatography II. ZIPAX(R) The Effect of Particle Size

Abstract

The reduced plate height has been measured as a function of reduced fluid velocity for Zipax fractions of mean particle diameters, 29, 39, 49, and 106 µm coated with 0.5% and 1% ββ′ oxydipropionitrile (BOP). As predicted by theory, identical (h,ν) curves are obtained for all four fractions. The (h,ν) plots show minima at 2<ν<10. Retained solutes show h-values which are 1.5 to 2 times those of unretained solutes. Since h rises to a maximum as the column capacity ratio k′ rises, there is little contribution to h from non-equilibrium in the stationary phase. Permeabilities of packings are reported which suggest that the flow rate is determined by the smaller particles present in a given fraction. The advantages of using reduced parameters to derive conditions for optimum performance are illustrated using experimental data, and it is shown that current HSLC methods can generate 10 plates per second for a solute with a retention ratio of R = 0.2.