Dispersion in Chromatography Columns - Dispersion Processes that take Place in an LC Column > Longitudinal Diffusion > The Diffusion Process > Page 17


Now,  from the Plate Theory (see Plate Theory and Extensions),


where (n) is the variance of the Gaussian curve.

Now, (n) is the volume variance of the Gaussian curve (i.e., ), then, by comparison, (2Dmt) will be the length variance  of the concentration curve where (t) is the elapsed time. Consequently, if a differential equation of the form  is derived that describes some form of dispersion that arises from a random diffusion process, then the solution will be a Gaussian function and, more important from the point of view of the Rate Theory, the Gaussian curve will have a variance given by (2Dmt).