Dispersion in Chromatography Columns - Dispersion Processes that take Place in an LC Column > The Multipath Process > Page 12

The Multipath Process

In a packed column the solute molecules will describe a tortuous path through the interstices between the particles and obviously some will travel shorter paths than the average and some longer paths. Consequently, some molecules will move ahead of the average and some will lag behind thus causing band dispersion. The multipath effect is illustrated in figure (4)

 

Figure 4.     Dispersion by the Multipath Effect

 

The Multipath effect can be applied to the Random Walk Model. The average path length is equivalent to the mean diameter of the particle (dp) and thus the number of steps will be equivalent to the column length divided by the average step  i.e.   .

Thus, applying equation (1),