Temperature-Induced Changes in Reversed-Phase Chromatographic Surfaces: C7 and C8Monomeric Ligands

摘要

The temperature-dependent retention of phenol and resorcinol on a monomeric C8stationary phase, preconditioned with acetonitrile and then contacted with water, is investigated. These results are compared with the surface polarity of C7 and c8 monomeric ligands under similar conditions, the using the fluorescence vibronic band ratios of sorbed pyrene as a probe. Unlike polymeric stationary phases in the same size range, the solute elution and surface polarity of monomeric ligands indicate no persistent retention of the preconditioning solvent nor a distinct transition temperature for its accelerated loss. The results indicate that monomeric stationary phases are amorphous surface structures which do not achieve the same degree of conformational order as polymeric ligands; the results are consistent with previous studies of the shape selectivity of monomeric and polymeric phases. (jes)