SYSTEMATIC-APPROACH TO OPTIMIZING RESOLUTION IN REVERSED-PHASE LIQUID-CHROMATOGRAPHY, WITH EMPHASIS ON THE ROLE OF TEMPERATURE

A general model for the easy optimization of separation in reversed-phase liquid chromatographic system has been developed, for use on hand-held or desktop programmable calculators. A small number of experimental data (minimum of four different conditions) are used to generate semi-empirical estimates of K′ and a for various values of temperature and mobile-phase composition (methanol-water, in present study). These latter k′ and a data are then combined with theoretical values on N from the Knox equation to allow the calculation of resolution as a function of all experimental parameters. Resolution can easily be mapped for time-normalized separation, fixed or variable column length fixed operating pressure, etc. This allows the easy optimization of the final separation in terms of any set of initial constraints. It is seen that temperature plays an important role in such separations, when mobile-phase composition and temperature are adjusted simultaneously to maintain fixed (i.e., optimum) values of k′. Resolution is generally improved at higher values of separation temperature ( and accompanying lower concentrations or organic in the mobile phase). Exceptions to this rule are noted and discussed. © 1979.