# Dispersion in Chromatography Columns - The Van Deemter Equation > Page 48

Equation (31),
however, was developed for a GC column and in the case of an LC column, the
resistance to mass transfer in the mobile phase should be included. Van Deemter
*et al.* did not derive an expression for f_{1}(k') for the mobile phase but Purnell (10) suggested that
the function of (k'), employed by Golay (8) for the resistance to mass transfer
in the mobile phase in his rate equation for capillary columns, would also be
appropriate for a packed column. The form of f_{1}(k')
derived by Golay was as follows,

_{}

Thus, Van Deemter's equation for LC becomes,

_{} (32)

Equation (32 ) can put in a simplified form as follows,

_{} (33)