Preparation of two amide bonded stationary phases and comparative evaluation under mixed-mode chromatography.

Abstract

In this work, the conventional reactions were used to functionalize the silica surface with amide and hydrocarbon chain groups affording two different mixed-mode stationary phases (Sil-amide-C11 and Sil-C12-amide). The prepared stationary phases were analyzed by elemental analysis and thermogravimetric analysis. The retention of benzene, phenol, pyridine, and aniline was investigated and compared on synthesized and commercial columns, this led to prove the existence of different interactions on the synthesized stationary phases. The mixed-mode stationary phases showed multiple interactions and different chromatography modes were found under distinct chromatographic conditions. According to the type of amide group (either free or within hydrocarbon chain) different interactions can be made on the columns. The alkylbenzenes and polycyclic aromatic hydrocarbons, as non-polar hydrocarbons, were chromatographed under reversed phase liquid chromatography modes, in which amide groups on the silica could efficiently separate polar analytes under hydrophilic interaction liquid chromatography mode on both prepared stationary phases. The performance of the columns was comparted by the separation of the carboxylic acid group and biological samples. The bonding method and the type of amide group showed different interactions leading to the different separation and performance. This article is protected by copyright. All rights reserved.