Zirconia nanoparticles-coated column for the capillary electrochromatographic separation of iron-binding- and phosphorylated-proteins

Abstract

A ZrO(2) nanoparticles (ZrO(2)NPs)-coated column was prepared through a sol-gel process using zirconium(iv) oxychloride, which reacted with silanol groups of the fused-silica capillary. The condensation reaction was carried out at 350 °C for 8 h. Electroosmotic flow (EOF) measurements and scanning electron microscopy (SEM) images were used to characterize the ZrO(2)NPs fabricated on the inner wall of the capillary. Below the pI value (pH 5-6), cathodic EOF elucidated that the phosphate buffer adsorbs tightly on the zirconia surface, resulting in a negatively charged surface. In this work, iron-binding proteins, phosphorylated proteins and glycoproteins were selected as the model compounds. The effects of pH, concentration, buffer type and the organic modifier were studied to optimize the separation efficiency. Iron-binding proteins exhibited a retention time for myoglobin (Mb) < hemoglobin (Hb), which corresponded to the binding constants for ZrO(2)NPs. The α- and β-subunit of Hb could be separated in borate buffer (20 mM, pH 9.0) with MeOH (20%, v/v). Greater affinity of α-casein and bovine serum albumin (BSA) for the stationary phase as the pH decreased was found by comparison with that of conalbumin (ConA) and transferrin (Tf). Interestingly, 14 peaks for glycoisoforms of ovalbumin (OVA) were observed using borate buffer (40 mM, pH 9.0). The established method was also applied to the determination of analytes in the egg whites of chicken and duck eggs.

Less common applications of monoliths: V. Monolithic scaffolds modified with nanostructures for chromatographic separations and tissue engineering

“…For example, open tubular stationary phase was prepared in a fused silica capillary using sol–gel technique and applied for separation of angiotensin‐type oligopeptides []. Affinity of titanium dioxide [] and zirconium dioxide [] nanoparticles toward phosphate groups of natural biopolymers was demonstrated with CEC separation of phosphoproteins.…”

Carboxyl modified magnetic nanoparticles coated open tubular column for capillary electrochromatographic separation of biomolecules

“…However, due to the limited amount of stationary phase coating, low phase ratio and sample capacity of OT columns are the primary drawbacks and restrict their widespread application in electrochromatographic separations. To overcome these shortcomings, a series of innovative approaches such as sol-gel derived phases [4,5], etching [6], porous layers [7,8] and nanoparticles (NPs) phases [9][10][11][12][13][14][15][16][17][18][19] have been developed to increase the inner surface area of columns and enhance the stationary/mobile phase interactions in OT-CEC separations. Among these approaches, NPs modified OT columns show a great promise to enhance the separation efficiencies of complex samples since NPs possess larger surface-to-volume ratio.…”

“…For the past two decades, NPs with unique physical and chemical properties have made a significant contribution to the development of stationary phases in CEC, such as carbon NPs [9][10][11][12], silica NPs [13,14], metallic and metal-oxide NPs [15][16][17][18], and polymer NPs [1]. As one kind of extensively studied NPs, magnetic nanoparticles (MNPs) have received great attention for their superior characteristics such as good dispersion, excellent biocompatibility [20], high field irreversibility, ease of preparation, high ratio of surfaceto-volume [19] and remarkable physicochemical stability.…”

Selective adsorption of protein by a high-efficiency Cu2+-cooperated magnetic imprinted nanomaterial

“…Low‐abundance proteins play an important role in diagnosing and treating disease, whereas they are always hard to be dislodged because of the shield effect of high‐abundance proteins . Therefore, the depletion of high‐abundance proteins is prerequisite step in facilitating access to analysis low‐abundance proteins.…”