Studies of retention and stability of a horizontally polymerized bonded phase for reversed-phase liquid chromatography

We have studied the novel horizontally polymerized mixed trichloropropyl-tr ichlorooctadecyl silane bonded phase described by Wirth. These materials ca n be reproducibly prepared and give very high bonded phase density (>7.5 mu mol m(-2)), They show significantly improved alkaline stability and chroma tographic selectivity towards PAHs similar to conventional monomeric phases . Study of retention by the Linear Solvation Energy Relationship approach a s well as measurement of dead volume and retention of methanol indicate tha t less mobile phase is sorbed by a horizontally polymerized phase than by c onventional phases. Silanophilic interaction of amines are decidedly weaker on a silica modified by horizontal polymerization compared to a convention ally modified phase. In addition, this work provides additional support for the "partition-like" retention mechanism of bonded phase RPLC. (C) 2000 El sevier Science B.V. All rights reserved.