In-line application of electric field in capillary separation systems: Joule heating, pH and conductivity.

This study concerns the technique electric field-assisted capillary liquid chromatography. In this technique, an electric field is applied over the separation capillary in order to provide an additional selectivity. In this technique, the electric field is applied in-line in the separation capillary and here the electric current is the factor limiting the magnitude of applied electric field.

Enantiomeric separation of omeprazole and its metabolite 5-hydroxyomeprazole using non-aqueous capillary electrophoresis.

This study demonstrates the development and validation of a non-aqueous capillary electrophoresis (NACE) method for enantiomeric determination of omeprazole and its metabolite 5-hydroxyomeprazole. Heptakis-(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD) was chosen as the chiral selector in an ammonium acetate buffer acidified with formic acid in methanol. Parameters such as CD concentration, concentration of buffer electrolyte, voltage and temperature were studied in order to optimize both the enantioresolution and migration times.

Separation of biomolecules by micro-high-performance anion-exchange chromatography using a tentacle-like stationary phase.

A variety of biomolecules and their variants, which have previously been problematic to separate, have been analysed using a novel anion-exchange resin based on a non-porous polystyrene polymeric support with a hydrophilic coating and grafted tentacular quaternary ammonium functional groups. The hydrophilic coating results in minimal interaction between the support and the biomolecule, while the highly flexible tentacular-like anion-exchange groups increase the ionic interaction potential and act as an umbrella to hold the proteins away from the surface. Because of the removal of silanophilic interactions, minimisation of hydrophobic interactions, and the highly flexible nature of the tentacle-like ion exchangers, ionic interactions can therefore dominate the separation.

Comparison of styrene-divinylbenzene-based monoliths and Vydac nano-liquid chromatography columns for protein analysis.

This report details the fabrication of polystyrene-based nano-LC monolithic columns for the separation of protein molecules. The report focuses on the practical advantages of monolithic columns when compared to conventional packed columns. Capillary columns were made to 100 and 50 microm i.

Advances in capillary electrochromatography and micro-high performance liquid chromatography monolithic columns for separation science.

Over the last decade, monoliths or continuous beds have emerged as an alternative to traditional packed-bed columns for use in capillary electrochromatography (CEC) and micro-high performance liquid chromatography (micro-HPLC). Monolithic columns can be divided into two categories: silica-based monolithic columns and rigid organic polymer-based monolithic columns resulting from the polymerization of acrylamide, styrene, acrylate or methacrylate monomers. In this paper, the chemistry and most recent applications of these various types of monoliths in both CEC and micro-HPLC are presented.