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Capillary electrochromatography with monolithic silica columns. IV. Electrochromatographic characterization of polar bonded monolithic stationary phases having surface‐bound cyano functionalities
Author(s) -
Zhong Hengwen,
El Rassi Ziad
Publication year - 2006
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200600074
Subject(s) - monolith , monolithic hplc column , mesoporous material , capillary electrochromatography , capillary action , chemistry , adsorption , chromatography , chemical engineering , mesoporous silica , phase (matter) , materials science , high performance liquid chromatography , capillary electrophoresis , composite material , organic chemistry , catalysis , engineering
Two polar ligands, namely 3‐hydroxypropionitrile and 1 H ‐imidazole‐4,5‐dicarbonitrile (IDCN) were covalently attached to epoxy‐activated silica‐based monolithic capillary columns via an epoxide ring‐opening reaction to yield CN–OH‐Monolith and 2CN–OH‐Monolith, respectively. The silica monolith was prepared by a sol–gel process, and the resulting “rod‐like” stationary phase was subjected to pore tailoring with an alkaline solution to convert small pore domains to mesopore domains, thus yielding a monolith with bimodal pore structure consisting of flow through pores ( i. e. , flow channels for mobile‐phase flow) and mesopores that provide most of the adsorption capacity of the monolith toward the separated solutes. The two polar monoliths, CN–OH‐Monolith and 2CN–OH‐Monolith, were evaluated in normal‐phase CEC with organic‐rich mobile phases less polar than the stationary phase. The 2CN–OH‐Monolith bearing more polar functions than the CN–OH‐Monolith exhibited more retention and improved selectivity toward model polar solutes.