COMPUTER-SIMULATION FOR THE PREDICTION OF SEPARATION AS A FUNCTION OF PH FOR REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY .2. RESOLUTION AS A FUNCTION OF SIMULTANEOUS CHANGE IN PH AND SOLVENT STRENGTH

The optimization of reversed-phase high-performance liquid chromatographic separation by the simultaneous variation of pH and solvent strength (%B) was studied for acidic (substituted benzoic acids) and basic samples (substituted anilines). The combination of these two variables was expected to be more useful than either variable alone. This proved to be the case for the benzoic acid sample, but not for the aniline sample. Column plate numbers were also studied for each sample and as a function of pH. With the exception of one compound (3,5-dimethylaniline) in one particular pH range (3.0-4.5), plate numbers of 12 000-20 000 were observed for each sample.