Dispersion in Chromatography Columns - Resistance to Mass Transfer Dispersion > Diffusion Controlled Dispersion in the Mobile Phase > Page 32

   In addition,         s = tmu      and           

             or        .                  (17)


Substituting for (tm) from (16) in (17)



     Thus,                                  (18)

Equation (21) applies to all types of columns each requiring a different constant (wm) which is partly determined by the geometry of the distribution system and partly by the capacity ratio of the solute. A function for (wm) has not been developed for packed LC or GC columns, but due to the geometric simplicity Golay (8) was able to develop the function for the capillary column ,viz.