Preparation of continuous beds derivatized with one-step alkyl and sulfonate groups for capillary electrochromatography

A simple one-step procedure for the preparation of columns for capillary electrochromatography is described, The nonpolar compounds (stearyl or butyl methacrylate) used for the introduction of hydrophobic ligands (C18, C4) are rendered water-soluble in the aqueous monomer mixture used for the synthesis of the matrix by the addition of a surfactant, This solution is sucked into a piece of fused silica tubing, the inner walls of which are activated by methacryl groups. Following polymerization, the continuous bed column is ready for use, Since the bed is attached covalently to the tubing wall, no hit to support the bed is required, which simplifies the preparation of the column. In addition, a frit can easily become clogged and is often a site for the generation of air bubbles. Some new approaches to increase the resolution and shorten the analysis times in electrochromatography are suggested and demonstrated experimentally, such as sharpening the starting zone, employing gradient elution, or adding SDS (below cmc) to the mobile phase, Separation of five polycyclic aromatic hydrocarbons can be achieved in 5 min in a 25-mu m-i.d. column.