ABSTRACT
I. INTRODUCTION Isoelectric focusing (IEF) is the highest resolution technique used in biomolecule analysis [1,2]. It is traditionally performed in slab gels. As an analytical technique, gel IEF is slow, labor intensive, and generally not quantitative [3]. Since the appearance of capillary electrophoresis (CE) with high speed and quantitative properties, it was recognized that if IEF could be performed in a capillary format, it would greatly decrease IEF time, increase quantitation, make it easy to automate, and further enhance the separation resolution. In 1985, Hjerten and Zhu first reported high-resolution IEF performed in a gel-free capillary column [4]. Since then, many studies of capillary IEF (cIEF) have been reported [5-9], and CE manufacturers began developing and eventually commercialized cIEF kits and accessories offering cIEF analysis capabilities on existing CE instruments.
