title: "One-pot" preparation of basic amino acid-silica hybrid monolithic column for capillary electrochromatography.
abstract: A novel "one-pot" strategy was developed for the preparation of amino acid (AA)-silica hybrid monolithic column. The basic AA (L-Arginine, L-Lysine and L-Histidine) was covalently incorporated into the silica hybrid skeleton via the epoxy ring-opening reaction between the amine group and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS), which was confirmed by elemental analysis and FT-IR studies, while the basic AA was also found to catalyze the polycondensation of tetramethoxysilane and GPTMS. The average mesopore and macropore sizes of the prepared basic AA-silica hybrid monolithic columns were 3.86 nm and 1.71 μm for the L-Lysine-silica hybrid monolith, 5.38 nm and 4.24 μm for the L-Arginine-silica hybrid monolith, and 6.38 nm and 1.24 μm for the L-Histidine-silica hybrid monolith. The hybrid monolith afforded a zwitterionic stationary phase for CEC, the direction and magnitude of EOF can be controlled by the pH of the mobile phase used. Besides an electrophoretic mechanism, the monoliths behave in a typical hydrophilic interaction with the analytes when ACN percentage in the mobile phase is over 40%. Four polar compounds (toluene, DMF, formamide and thiourea) were tested on the three AA-silica hybrid monolithic columns, and the best separation efficiency was observed in the L-Lysine-silica hybrid monolithic column, its theoretical plate height was down to 5.7 μm for thiourea when 20 mM HCOOH-HCOONH4 containing 20% ACN (pH 4.1) was used as a running buffer. The corresponding theoretical plate number for toluene, DMF, formamide and thiourea were 123,385, 103,620, 121,845 and 105,345 plates/m, respectively. Effective separation of phenols and peptides on the L-Lysine-silica hybrid monolithic column was achieved using CEC. We believe that this strategy paves a way for the easy preparation of various functional silica hybrid monolithic columns, aiming at different separation purposes.
authors.affiliation: Department of Chemistry and the Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, P. R. China.
authors.forename: Hongrui
authors.initials: H
authors.lastname: Xu
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Xu
authors.forename: Limin
authors.initials: L
authors.lastname: Yang
authors.forename: Qiuquan
authors.initials: Q
authors.lastname: Wang
mesh_terms: D001120:Arginine / Q000737:chemistry*; D053801:Capillary Electrochromatography / Q000295:instrumentation* / Q000379:methods; D006639:Histidine / Q000737:chemistry*; D008239:Lysine / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D011108:Polymers; D006639:Histidine; D012822:Silicon Dioxide; D001120:Arginine; D008239:Lysine