Characterization of the polarity of reversed phase liquid chromatographic stationary phases in the presence of 1-propanol using solvatochromism and multivariate curve resolution

This work characterizes solvation effects in reversed-phase liquid chromato graphy in the presence of 1-propanol, The solvatochromic method combined wi th a multivariate curve resolution-alternating least-squares analysis metho d has been used to characterize two modified silica surfaces-phenyl bonded and C-18 bonded silica in mobile-phase mixtures of methanol-water and aceto nitrile-water in the presence of 1-propanol. The presence of a small amount of 1-propanol has been shown to affect mainly the polarity properties of t he stationary phases while the mobile-phase properties are largely unaffect ed. The chain collapse mechanism for the C1s stationary phase at higher con centrations of water seems to be inhibited in the presence of 1-propanol, a nd partitioning is the predominant solute retention mechanism, The phenyl-b ased phase shows considerably different behavior from that of the C1s phase , and propanol appears to disrupt the pi -stacking interactions between the solute and the phenyl rings anchored to the silica support.