Capillary electrochromatographic separation of proteins on a column coated with titanium dioxide nanoparticles

Abstract

A TiO2 nanoparticle (TiO2 NP)-coated open-tubular column for the capillary electrochromatographic separation of proteins is described. The surface chemistry of the TiO2 NPs on the inner wall of the fused silica was significantly affected by the running buffer. By varying of the phosphate buffer pH, only cathodic EOF was indicated. The results showed that TiO2 NPs are existed as a complexed form with the buffer ligand. Good separation of conalbumin (ConA), apo-transferrin (apoTf), ovalbumin (OVA), and BSA could be achieved with phosphate buffer (40 mM, pH 8.0) and an applied voltage of 15 kV. Five peaks of glycoisoforms of OVA were observed under these conditions. In comparison with the retention behavior of the analytes on the bare fused-silica column, the new column's high resolving power seems to be predominantly derived from the ligand exchange of the analytes with the phosphate adsorbed onto the TiO2 NPs. The method was also used to separate egg-white proteins. Both acidic and basic proteins in egg white were separated in a single run. The microheterogeneities of OVA could also be found in it. The separation efficiency for the main peak of OVA in egg white was around 10,000 plates/m.

Polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography

“…Taken advantage of their property of large surface area, to date, the nanostructured materials, such as carbon nanotubes, silica, magnetic and non-magnetic metal oxides, silver and gold nanoparticles, have been adopted in chromatographic and electrophoretic techniques, in which nanoparticles serve as additives, or permanent/dynamic capillary inner surface coatings in capillary electrophoresis (CE) [2][3][4][5], as stationary phases in capillary electrochromatography (CEC) [6][7][8][9][10][11][12] and gas chromatography (GC) [13,14], as well as liquid chromatography (LC) [15].…”

Open‐tubular capillary electrochromatography using a capillary coated with octadecylamine‐capped gold nanoparticles

“…Open tubular capillaries have advantages over packed capillary columns in several aspects including ease of preparation, no bubble formation, and simple instrumental handling. The main methods used to prepare the stationary phase for the open tubular CEC (OTCEC) include chemical bonding [1][2][3][4], sol-gel derived phases [5,6], molecular imprinting [7], porous layers [8,9], physical coating [10][11][12], and nanoparticle phases [13][14][15][16][17][18]. Among these techniques, coating of capillaries with nanoparticles provided high separation efficiencies for various analytes [19].…”

A novel open‐tubular capillary electrochromatography with magnetic nanoparticle coating as stationary phase

“…Furthermore, the absence of plunger piston can also diminish the possibility of bubble formation. However, the OT-CEC column has limitation in the separation of complex samples because of its low phase ratio and small column capacity [11]. One of the trends in the development of OT-CEC is using small particles, even nanoparticles as the stationary phase.…”

“…Nowadays, the applications of nanoparticles in chromatography mainly focus on pseudostationary phases in capillary electrochromatography (PSP-CEC) [7][8][9][10] and open-tubular (OT) CEC [11][12][13][14], and high pressure are not necessary in both methods. Neiman et al [9] prepared organically modified silica sols for PSP-CEC separation.…”