Chromatographic classification and comparison of commercially available reversed-phase liquid chromatographic columns containing phenyl moieties using principal component analysis

Twenty-one commercially available phenyl type RPLC packing materials have been characterized in terms of their surface coverage, hydrophobic selectivity, shape selectivity, hydrogen bonding capacity, ion exchange capacity at pH 2.7 and 7.6 and aromatic selectivity (i.e. pi-pi interaction). The phases have been compared to their corresponding C-alkyl phases, three pentafluorophenyl phases and a series of experimental phenyl phases of known bonding chemistry. Principal component analysis has been used to provide a graphical comparison of the differences and similarities between the phases. The phase's aromatic selectivity was found to be dependent on the length of the alkyl spacer between the silicon atom and the phenyl ring.