Analytical separations in open‐tubular capillary electrochromatography

Abstract

This review represents a summary of recent progress in open‐tubular capillary electrochromatography (OT‐CEC) for chiral and achiral separations. The OT‐CEC approach is an alternative to packed‐CEC that could eliminate the problems associated with retaining frits and silica particles. In OT‐CEC, the stationary phase is immobilized on the inner walls of the capillary. Preparation of the stationary phase is critical for OT‐CEC. The preparation methods for capillary columns include (i) adsorption, (ii) covalent bonding and/or cross‐linking, (iii) porous layers, (iv) chemical bonding after etching, (v) sol‐gel, and (vi) molecular imprinting. Major developments, potential applications, technical difficulties and advantages associated with these wall coatings in OT‐CEC are presented. In addition, the coupling of OT‐CEC with mass spectrometry (MS) is briefly reviewed. Several applications of this hyphenated technique for analytical separations are also summarized.