Effect of the type of commercially available mixed-mode stationary phases on the retention of pharmaceutically important acidic and neutral compounds using different compositions of mobile phase
Abstract
Four different columns with mixed-mode properties were used to investigate the retention behavior of four acidic compounds (ascorbic, nicotinic, p-toluenesulfonic, and p-hydroxybenzenesulfonic acids) and two neutral compounds (dexamethasone and paracetamol). The effect of mobile phase composition (acetonitrile content and buffer pH) on the retention of the analytes was studied to better understand the separation role of an ion-exchange group position within a stationary phase for acidic analytes.
The impact of C18 hydrophobic moiety, identical for all the tested stationary phases, was studied on retention of two neutral compounds via selected parameters characterizing the investigated stationary phases. The results obtained were compared and discussed with data previously reached using an Acclaim(TM) WAX-1 mixed-mode column.