Capillary electrochromatography using monoamine- and triamine-bonded silica nanoparticles as pseudostationary phases

Monoamine- and triamine-bonded silica nanoparticles were prepared using 3-aminopropyltrimethoxysilane and N(1)-(3-trimethoxysilylpropyl)diethylenetriamine, respectively, and used as pseudostationary phases for capillary electrochromatography. The amine-bonded silica nanoparticles were tightly adsorbed on the inner wall of a capillary and generated fast electro-osmotic flow (2.59 × 10(-4) cm(2) V(-1) s(-1)) toward the anode in an electric field. The electro-osmotic velocities obtained with 20 nm triamine-bonded silica were three to five times larger than those generated by a fused silica capillary and two times faster than those for the commercial cationic polymer-modified capillary. Fast electro-osmotic flow enables rapid analysis. This method was applied to hydrophilic interaction chromatography (HILIC) mode separation of various samples including the size separation of glucose oligomer derivatives and the resolution of four nucleic acid bases.