Fritless capillary columns for HPLC and CEC prepared by immobilizing the stationary phase in an organic polymer matrix

A new design of immobilized particle separation media for capillary liquid chromatography and electrochromatography has been developed. A mixture of porogenic solvents and methacrylate-based monomers is pumped through a packed column to provide, following a polymerization step, an organic matrix capable of holding the sorbent particles in place, thus rendering the end frits unnecessary. The new columns demonstrate excellent chromatographic performance in both CEC (reduced plate height [h]=1.1-1.5) and micro LC modes (h = 2.2-2.5), while minimizing secondary interactions encountered when silica-based entrapment matrixes are employed. In addition to delivering mechanically robust columns, the methacrylate matrix provides a mechanism for fine tuning of the electroosmotic flow velocity when 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) is incorporated into the polymerization mixture.