[Separation of 1-phenyl-3-methyl-5-pyrazolone derivatives of traditional Chinese medicine oligosaccharides by capillary zone electrophoresis].

A simple and practical capillary zone electrophoretic (CZE) method has been developed for the separation of traditional Chinese medicine oligosaccharides according to their relative molecular masses (M(r)). To optimize the conditions of the method, the concentration and pH value of the running buffer, and the applied voltage were evaluated. The optimized conditions were as follows: 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatives of the oligosaccharides were separated with 50 mmol/L phosphate buffer (pH 2.5) as running buffer and the voltage was 15 kV. The detection was performed with an ultraviolet detector at 245 nm. An uncoated fused-silica capillary of 50 microm i. d. and 38/48 cm length (effective length/total length) was employed, and a hydrodynamic pressure injection (10 cm x 2 s) was applied. In order to examine the practicability of the method for the analysis of actual traditional Chinese medicine oligosaccharide samples, a complex sample consisting of some usual monosaccharides and oligosaccharides degraded from beta-cyclodextrin was separated under the electrophoretic conditions. And then, the method was applied to the analysis of the controlled degradation products of Indigowoad Root polysaccharide. The results indicated that the oligosaccharide sample could fully be separated from low to high M(r). This method is efficient and practical. In addition, the separation hypothesis of PMP derivatives of monosaccharides and oligosaccharides in pH 2.5 running buffer is also discussed, which would be helpful for us to understand the unusual migration of the PMP derivatives of rhamnose and mannose.