Capillary electroendoosmotic chromatography of peptides

This review focuses on the current state of peptide separation by capillary electroendoosmotic chromatography (CEC). When carried out under optimised conditions, peptide separation by CEC methods represents an orthogonal and complementary technique to micro-HPLC (μ-HPLC) and high-performance capillary zone electrophoresis (HPCZE). The origin of the selectivity differences that can be achieved with these three separation techniques (CEC, μ-HPLC and HPCZE), respectively are discussed, and the current limits of performance with CEC methods documented. Peptide separations by CEC methods with n-alkyl bonded silicas or mixed-mode phases are also illustrated. The development of different variants of CEC and pressurised CEC (also commonly referred to in the literature as electrically-assisted μ-HPLC) are examined. The potential of coupling CEC systems to mass spectrometers for real-time analyses of peptides or protein digests has been examined. Several future directions for the application of this technique in phenotype/proteomic and zeomic mapping of naturally occurring peptides and proteins are highlighted.