Liquid chromatography capillary columns dry‐packed with polar and nonpolar stationary phases

Fused silica capillary columns of 0.250‐mm i.d., packed with 5‐μm particles of nonpolar (octadecyl, octyl, and butyl) and polar (silica, diol, cyano, and amino) materials, have been prepared using a dry‐packing technique. The performance of the columns has been evaluated using the reduced plate height/reduced velocity equation and the separation impedance values. A comparison with similar slurry‐packed columns shows that the dry‐packing method may yield, in most cases, columns of analogous or better efficiency and requires a simpler apparatus and a shorter time for column preparation.