CHEMICALLY BONDED SILICA STATIONARY PHASES - SYNTHESIS, PHYSICOCHEMICAL CHARACTERIZATION, AND MOLECULAR MECHANISM OF REVERSED-PHASE HPLC RETENTION

Two types of chemically bonded phases for high-performance liquid chro matography (HPLC) have been prepared: a conventional C18 and AP (N-acy laminopropylsilica), a novel one that contains specific interaction si tes localized in the hydrophobic chain, Surface properties of stationa ry phases, before and after chemical modification, have been character ized by several physicochemical techniques, such as porosimetry, ICP a tomic emission spectroscopy, elemental analysis, solid state CP/MAS NM R, and chromatography, For the studies of the reversed-phase HPLC rete ntion mechanism under hydroorganic conditions, a test series of struct urally diverse solutes has been selected, Sets of retention parameters and structural descriptors of the test solutes were subjected to mult iparameter regression analysis, The quantitative structure-retention r elationships derived demonstrated the typical reversed-phase partition mechanism to predominate in the separation on the C18 phases but not on the AP phases, The AP phases were demonstrated to provide significa nt input to retention due to the structurally specific dipole-dipole a nd charge transfer interactions with the solutes. The proposed AP phas es for HPLC possess distinctive and interesting retentive properties, and chemometric analysis of retention data of appropriately designed s eries of test solutes appears to be a convenient, objective, and quant itative method to prove a new phase specificity.