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Neutral octadecyl monolith for reversed phase capillary electrochromatography of a wide range of solutes
Author(s) -
Karenga Samuel,
El Rassi Ziad
Publication year - 2008
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.200800310
Subject(s) - monolith , capillary electrochromatography , chemistry , electrochromatography , monolithic hplc column , chromatography , adsorption , capillary electrophoresis , phase (matter) , analytical chemistry (journal) , high performance liquid chromatography , organic chemistry , catalysis
A neutral octadecyl monolithic (ODM) column for RP capillary electrochromatography (RP‐CEC) has been developed. The ODM column was prepared by the in situ polymerization of octadecyl acrylate (ODA) as the monomer and trimethylolpropanetrimethacrylate (TRIM) as the crosslinker, in a ternary porogenic solvent containing cyclohexanol, ethylene glycol, and water. The ODM column exhibited cathodal EOF over a wide range of pH and ACN concentration in the mobile phase despite the fact that it was devoid of any fixed charges. It is believed that the EOF is due to the adsorption of ions from the mobile phase onto the surface of the monolith thus imparting to the neutral ODM column the zeta potential necessary to support the EOF required for mass transport across the monolithic column. Furthermore, the adsorption of mobile phase ions to the neutral monolith modulated solute retention and affected the separation selectivity. The wide applications of the neutral ODM column were demonstrated by its ability to separate a wide range of small and large solutes, both neutral and charged. While the separation of the neutral solutes was based on RP retention mechanism, the charged solutes were separated on the basis of their electrophoretic mobility and hydrophobic interaction with the C18 ligands of the stationary phase. As a typical result, the neutral monolithic column was able to separate peptides quite rapidly with a separation efficiency of nearly 200 000 plates/m, and this efficiency was exploited in tryptic peptide mapping of standard proteins, e. g. , lysozyme and cytochrome C , by isocratic elution.