USE OF PARTIAL MOLAR ENTHALPIES FOR THE CHARACTERIZATION OF STATIONARY LIQUID PHASES.

A new approach to the characterization of stationary phases in GLC is presented. An absolute system is developed utilizing the differential enthalpies of evaporation from solution left bracket DELTA H right bracket , which is determined from the temperature dependence of the specific retention volume. Assuming additivity of the functional groups, the partial DELTA H for the functional groups in the Rohrschneider solutes are reported on sixteen stationary phases. From this it is possible not only to characterize stationary phases by the total molecular DELTA H for standard solutes, but also to characterize stationary phases by the specific functional group DELTA H. In addition, it is possible to predict specific retention volumes at different temperatures from known functional group contributions in the solute molecule providing that the entropy term is neglected.