Phenylaminopropyl silica - a new specific stationary phase for high-performance liquid chromatography of phenols

The chromatographic properties of a new stationary phase, phenylaminopropyl silica (PhA-silica), containing phenylaminopropyl residues covalently bond ed to the silica surface were studied. The presence of secondary amino grou ps, phenyl rings and alkyl linkers in the attached molecule makes it especi ally suitable for the separation of phenols by mixed mode retention mechani sm including a combination of hydrogen-bonding, hydrophobic, electrostatic and pi-pi interactions with the stationary phase. The effects of mobile pha se pH, ionic strength, nature and concentration of organic modifier on the retention of phenols on PhA-silica were investigated under conditions of re versed-phase HPLC. To elucidate the role of the amino group in the attached molecule in retention of phenols the selectivity of PhA-silica was compare d with that obtained for phenylpropyl silica in the framework of a linear s olvation energy relationship (LSER) model. The isocratic separation of phen ol, and its nine methyl-, chloro- and nitro-substituted derivatives was ach ieved on a 150x4.6 mm I.D. chromatographic column packed with 7 mum particl es of PhA-silica. (C) 2000 Elsevier Science B.V. All rights reserved.