Review Sebastiaan Eeltink 1 Gerard P. Rozing 2 Wim Th. Kok 1 1 Polymer-Analysis Group, Department of Chemical Engineering, University of Amsterdam, Amsterdam, The Netherlands 2 Life Science and Chemical Analysis, Pharmaceutical Solutions, Agilent Technologies, Waldbronn, Germany Recent applications in capillary electrochromatography The most recent and important applications in capillary electrochromatography (CEC) are summarized, covering literature published since May 2001. A selection of new developments in stationary phases for CEC is highlighted, and enantiomeric separa- tions and chiral stationary phases are discussed. Also, CEC applications of biological molecules, pharmaceuticals, and applications in the field of industrial and environ- mental analysis are summarized. For this review three modes of CEC were taken into account, i.e., packed-column CEC, CEC using monolith technology, and open-tubular CEC. Keywords: Capillary electrochromatography / Review DOI 10.1002/elps.200305638 Contents 1 Introduction .......................... 3935 2 New developments in stationary phases for CEC .............................. 3936 2.1 Monolithic stationary phases ............ 3936 2.2 Stationary phases for OT-CEC ........... 3937 3 Enantiomeric separations ............... 3938 3.1 Chiral stationary phases and applications . . 3938 3.2 Chiral additives and applications ......... 3941 4 Applications in biochemical analysis ...... 3941 4.1 Amino acids and amines ................ 3941 4.2 Peptides ............................. 3941 4.3 Proteins.............................. 3943 4.4 Nucleosides and nucleotides ............ 3944 4.5 Carbohydrates ........................ 3944 5 Pharmaceutical applications ............. 3945 5.1 Steroids ............................. 3945 5.2 Acidic drugs .......................... 3946 5.3 Basic drugs .......................... 3946 5.4 Vitamins and food components .......... 3947 5.5 Miscellaneous ........................ 3948 6 Industrial and environmental applications . . 3948 6.1 Inorganic anions and cations ............ 3948 6.2 Synthetic polymers .................... 3948 6.3 (Poly)aromatics........................ 3949 6.4 Pesticides, insecticides, and herbicides . . . 3950 6.5 Miscellaneous ........................ 3951 7 References ........................... 3951 8 Addendum ........................... 3954 1 Introduction Capillary electrochromatography (CEC) is a miniaturized separation technique that combines aspects of both interactive chromatography and capillary electrophoresis. Analytes may be separated according to differences in partitioning ratio between the stationary and the mobile phase, and/or to differences in electrophoretic mobility. High separation efficiencies can be obtained in CEC in comparison to high-performance liquid chromatography (HPLC). This is mainly due to the characteristics of the electroendoosmotic flow (EOF). First, because of the absence of backpressure in CEC, smaller particles can be employed as stationary phase than in the pressure- driven HPLC. Moreover, the EOF is more homogeneous and less influenced by packing differences than a pres- sure-driven flow. Also, when a porous material is used as stationary phase, a flow through the pores of the particles may further improve the CEC separation efficiencies. There are several modes to perform CEC. Packed-col- umn CEC is still the most often used technique. Typically, 50–100 mm ID columns are employed packed with HPLC- type stationary phase particles. However, much research is devoted to the development of monolith technology for Correspondence: Dr. Wim Th. Kok, Polymer-Analysis Group, Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, NL-1018 WV, Amsterdam, The Nether- lands E-mail: wkok@science.uva.nl Fax: 131-20-525-5604 Abbreviations: AMPS, 2-acrylamido-2-methylpropane-sulfonic acid; COMOSS, collocated monolith support structures; ODS, octadecyl silane; OT , open-tubular; p-CEC, pressure-assisted CEC; PDMS, poly(dimethylsiloxane); SEEC, size-exclusion elec- trochromatography Electrophoresis 2003, 24, 3935–3961 3935 CE and CEC  2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim