Van Deemter equation The van Deemter equation relates the theoretical plate height, or efficiency, of a chromatographic column to the various flow and kinetic parameters which cause peak broadening, as follows:
HETP = A + B/u + C • u where:
• HETP = height equivalent to a theoretical plate, a measure of the dispersion value of the column [m];
• A = Eddy-diffusion parameter, related to channeling through a non-ideal packing [m];
• B = diffusion coefficient of the eluting particles in the longitudinal direction, resulting in dispersion [m2
s-1 ];
• C = Resistance to mass transfer coefficient of the analyte between mobile and stationary phase [s]; • u = Linear velocity [m s-1
