Influence of experimental parameters on chromatographic behavior of neutral, molecules in ion interaction chromatography

The chromatographic behavior of aprotic neutral molecules in Ion Interaction Chromatography (IIC) was investigated both theoretically and experimentally on a styrene-divinylbenzene based Cls stationary phase. The chemical modification of the stationary phase in the presence of Ion Interaction Reagent (IIR) in the eluent, and adsorption competition between tested analytes and IIR for inner layer sites are theoretically shown to change the partition coefficient for neutral molecules. Experimental evidence confirms that their retention decreases with increasing ion-interaction reagent (IIR) concentration in the eluent. The influence of the mobile phase ionic strength on neutral molecules retention was investigated and the dependence of retention modulus on organic modifier concentration in the eluent was elucidated.