Dispersion in Chromatography Columns - Effect of Mobile Phase Compressibility On the HETP Equation for a Packed GC Column > Page 40

   or       (25)

Substituting for (Px) from equation (25) in equation (24),


              Let               w =

Then                 or    

Furthermore, when x=0, then and when w = L, then .

Substituting for and  (dx) in  equation (26) and inserting the new limits and integrating,



Thus,                                                   (27)

Thus, the complete HETP equation for a packed GC column, that takes into account the compressibility of the carrier gas, will be