title: Characterization of electrophoretic behavior of sugar isomers by microchip electrophoresis coupled with videomicroscopy.
abstract: The electrophoretic behavior of oligosaccharide isomers was investigated by microchip electrophoresis (micro-CE) coupled with videomicroscopy using maltose, cellobiose, maltriose, and panose as oligosaccharide isomer models. The present study revealed for the first time that the formation of a carbohydrate-phosphate complex is a pH-independent rapid process, whereas the formation of a carbohydrate-borate complex is a highly pH-dependent slow process. As a result, phosphate buffer gave much better separation on oligosaccharide isomers than borate and borate-Tris buffers over a wide pH range in micro-CE. The imaging analysis of the complete process of sample loading and injection with field-amplified stacking (FAS) demonstrated that FAS could be used as an efficient method for manipulating the shape of injected sample plugs, and thus improving the performance of micro-CE in the absence of electroosmotic flow. However, once the ionic strength mismatch between sample and running buffer reached a critical threshold, a further increase in ionic strength mismatch deteriorated the effect of FAS, resulting in a surprising decrease in separation efficiency and peak distortion. Under optimal conditions, high-resolution separation of some oligosaccharide isomers and a complex oligosaccharide mixture released from ribonuclease B was achieved using PMMA microchips with an effective separation channel of 30 mm.
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, The University of Tokushima, CREST, Japan Science and Technology Corporation, Shomachi, Tokushima 770-8505, Japan. fuquan-dang@aist.go.jp
authors.forename: Fuquan
authors.initials: F
authors.lastname: Dang
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Mohammad
authors.initials: M
authors.lastname: Jabasini
authors.forename: Noritada
authors.initials: N
authors.lastname: Kaji
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Baba
mesh_terms: D002021:Buffers; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D007536:Isomerism; D018715:Microscopy, Video; D009844:Oligosaccharides / Q000032:analysis / Q000737:chemistry*; D012260:Ribonucleases / Q000737:chemistry
chemical_list: D002021:Buffers; D009844:Oligosaccharides; D012260:Ribonucleases