The Thermodynamics of Chromatography - Thermodynamics Basics > Page 4

Although the thermodynamic functions can be measured for a given distribution system, they can not, at present, be predicted before the fact. However, as will be seen in due course, the possibilities might be more hopeful for the future.

  

 

Despite these difficulties, the thermodynamic properties of a distribution system can help explain the characteristics of the distribution (i.e., the standard enthalpy and standard entropy involved) and predict, quite accurately, the effect of temperature on the separation.

Now,             V'r  =  KVs   and  

 

where (V'r) is the retention volume of the solute,
(Vs) is the volume of stationary phase in the column,
(Vm) is the volume of mobile phase in the column,
(a) is the phase ratio of the column,
and (k') is the capacity ratio of the solute.

Then, from equation (3),