Separation of peptides by open-tubular capillary electrochromatography using Fe(III)-deuteroporphyrin as a covalently attached stationary phase

The separation of seven biologically active peptides was attempted by open-tubular capillary electrochromatography in fused-silica capillaries chemically modified with iron (III)-deuteroporphyrin using UV-absorption detection at 214 nm. The effect of BGE pH and content of organic solvent modifier was investigated. The best separations were obtained in 25 mM phosphate (BGE), pH 4.0, containing 5% v/v ACN and 10 mM hydroquinone, which was added to prevent gas bubble formation. Considering the method sensitivity, lower concentration LODs were obtained for all peptides in their open-tubular capillary electrochromatography separation as compared with their CZE separation in bare fused-silica capillary. The iron (III)-deuteroporphyrin column proved to be highly stable over time and showed acceptable precision of migration times and corrected peak areas (RSD in the range 2-4%).