Dispersion in Chromatography Columns - The Golay Equation > Page 70

The Horvath and Lin Equation

In (1976) Horvath and Lin (23) introduced yet another equation to describe the value of (H) as a function of the linear mobile phase velocity (u). Their equation is given as follows,

                                          (51)

The equation of Horvath and Lin was very similar to that of Huber and Hulsman and, in fact, only differed in the magnitude of the power function of (u) in their (A) and (D) terms. These workers were also trying to address the problem of a zero (A) term at zero velocity and the fact that some form of "turbulence' between particles aided in the solute transfer across the voids between the particles.

The Golay Equation

The basic equation describing the dispersion that takes place in an open tubular column was developed by Golay (8) for GC but is equally, and directly, applicable to LC. The Golay equation differs in one important aspect from the equations for packed columns in that, as there is no packing, there can be no multipath term or coupling factor and thus, contains only two functions. One function describes the longitudinal diffusion effect and the other the combined resistance to mass transfer terms for the mobile and stationary phases.