Dispersion in Chromatography Columns - The Van Deemter Equation > Page 45

The Van Deemter Equation

The Van Deemter equation (9) was derived as long ago as 1956 and was the first rate equation to be developed. There are, however, a number of alternative rate equations that have been reported, but when subjected to experimental test, the Van Deemter equation has been shown to be the most appropriate equation for the accurate prediction of dispersion in chromatographic systems. The Van Deemter equation is particularly pertinent at mobile phase velocities around the optimum velocity (a concept that will shortly be explained). Consequently, as all columns should be operated at, or close to, the optimum velocity for maximum efficiency, the Van Deemter equation is particularly important in column design.

Restating the Van Deemter equation,

 

 

 

     where  f1(k")  =      and       f2(k") =