Preparation of ion exchange columns with longitudinal stationary phase gradients

Monolithic columns with mixed modes of reversed-phase and anion-exchange stationary phase for capillary electrochromatography.

A capillary electrochromatography (CEC) monolithic column with mixed modes of reversed-phase and anion-exchange stationary phases was prepared by in situ polymerization of 2-(methacryloxy)ethyltrimethylammonium methyl sulfate (MEAMS) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent consisting 1-propanol and 1,4-butanediol. The ammonium groups on the surface of the stationary pha...

Optimal packing characteristics of rolled, continuous stationary-phase columns.

Rolled, continuous stationary phases were constructed by tightly rolling and inserting a whole textile fabric into a chromatography column. This work reports the column performance, in terms of plate height, void fraction, and resolution, of 10 cellulose-based fabrics. The relation between fabric structural properties of yarn diameter, fabric count, fabric compressibility, and column performanc...

The preparation of diphosphopyridine nucleotide with ion exchange resin.

The older methods for the preparation of diphosphopyridine nucleotide (DPN) were reviewed in 1942 by Schlenk (1). In 1947 Sumner et al. (2) outlined the need for a greatly simplified method for the preparation of this coenzyme. These authors described a procedure which did away with heavy metal fractionation. Recently, Clark et al. (3) made several modifications in the above method. The LePage ...

Separation of protein charge variants with induced pH gradients using anion exchange chromatographic columns.

This work concerns the chromatographic separation of protein charge variants using pH gradients generated by step changes in buffer composition with weak base anion exchange columns. A local equilibrium model is first developed to describe pH transitions occurring in the column using buffers comprising neutral, zwitterionic or positively charged species. Model predictions, based solely on the r...

The Effects of Secondary Stationary-phase Polymers on Adsorption and Transport in Ion-exchange Chromatography