Interaction of heparin and tetraarginine in capillary electrophoresis: Implication for analytical applications

Investigation of metformin hydrochloride–bovine serum albumin interaction by narrow-bore capillary zone electrophoresis

A narrow-bore capillary (inner diameter = 2 μm) zone electrophoresis method was developed to study the interaction between metformin hydrochloride and bovine serum albumin. Free metformin hydrochloride, free bovine serum...

Recent developments in capillary and microchip electroseparations of peptides (2019-mid 2021)

The review provides a comprehensive overview of developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, microscale isolation, and physicochemical characterization of peptides from 2019 up to approximately the middle of 2021. Advances in the investigation of electromigration properties of peptides and in the methodology of their analysis, such as sample preparation, sorption suppression, EOF control, and detection, are presented. New developments in the individual CE and CEC methods are demonstrated and several types of their applications are shown. They include qualitative and quantitative analysis, determination in complex biomatrices, monitoring of chemical and enzymatic reactions and physicochemical changes, amino acid, sequence, and chiral analyses, and peptide mapping of proteins. In addition, micropreparative separations and determination of significant physicochemical parameters of peptides by CE and CEC methods are described.

Study of antagonism between some intestinal bacteria with high-speed micellar electrokinetic chromatography

In this work, high-speed micellar electrokinetic chromatography with LIF detection was applied to study the antagonism between three intestinal bacteria, Escherichia coli (E. coli), Bacillus licheniformis (B. licheniformis) and Bacillus subtilis (B. subtilis). The fluorescent derivatization for the bacteria was performed by labeling the bacteria with FITC. In a high-speed capillary electrophoresis (HSCE) device, the three bacteria could be completely separated within 4 min under the separation mode MEKC. The BGE was 1 × TBE containing 30 mM SDS and 1.5 × 10^-5  g/mL polyethylene oxide. The limits of detection for E. coli, B. licheniformis and B. subtilis were 2.80 × 10⁶ CFU/mL, 1.60 × 10⁶ CFU/mL and 1.90 × 10⁶ CFU/mL respectively. Lastly, the method was applied to investigate the antagonism between the three bacteria. The bacteria were mixed and cultured for 7 days. The samples were separated and determined every day to study the interaction between bacteria. The results showed that B. licheniformis and B. subtilis could not inhibit each other, but they could effectively inhibit the reproduction of E. coli. The method developed in this work was quick, sensitive and convenient, and it had great potential in the application of antagonism study for bacteria.

Mobilization of electroosmotic flow markers in capillary zone electrophoresis

UV-absorbing neutral substances are commonly used as markers of mean electroosmotic flow in capillary electrophoresis for their zero electrophoretic mobility in an electric field. However, some of these markers can interact with background electrolyte components and migrate at a different velocity than the electroosmotic flow. Thus, we tested 11 markers primarily varying in their degree of methylation and type of central atom in combination with five background electrolyte cations differing in their ionic radii and surface charge density, measuring the relative electrophoretic mobility using thiourea as a reference marker. Our results from this set of experiments showed some general trends in the mobilization of the markers based on the effects of marker structure and type of background electrolyte cation on the relative electrophoretic mobility. As an example, the effects of an inadequate choice of marker on analyte identification were illustrated in the electrophoretic separation of glucosinolates. Therefore, our findings may help electrophoretists appropriately select electroosmotic flow markers for various electrophoretic systems.