Application On The Fingerprint Of Chinese Traditional Medicine In Microemulsion Capillary Electrokinetic Chromatography

Microemulsion electrokinetic chromatography (MEEKC) is a new electrodriven separation technique, which was developled on the basis of micellar electrokinetic chromatography (MEKC). MEEKC has been applied to a wide rangeof water-soluble and insoluble both charged and neutral compounds, which has the wider migration window and higher separation efficiency than MEKC. This study we have developed the fingerprints of Rheum in MEEKC, compared with the fingerprints of Rheum in HPLC, Clustering has the same results essentially, which showed that MEEKC is another good technique in the research of fingerprints of Chinese medicine.First of all, In the system of microemulsion electrokinetic capillary chromatography, the effects of microemulsion compositions on migration window,including the surfactant, co-surfactant, core phases and organic modifiers were studied. Taking methanol as the electroosmotic flow marker and phenanthrene as the microemulsion drop marker, the migration window was analyzed.Research showed that the emulsion composition of anionic surfactant (SDS) and organic additive (methnol, acetonitrile) can increase the migration window significantly, and co-surfactant n-butanol makes the migration window smaller, in the meanwhile, the impact of oil is less. In order to get good separation results, we can adjust the migration window in the establishment of the fingerprints.Secondly, we have developed the fingerprints of Rheum collected from different producing areas by MEEKC, which can provide evidence for its quality control. A uncoated fused silicacapillary column(75μm×65cm,the length is 55 cm) was used, the O/W microemulsion system was used as buffer solution which was compose of SDS, n-octane, n-butanol, borate solution(the w/w was 3.3%∶6 .6%∶0 .8%∶8 9.3%), at an applied voltage of 18 kV, The wavelength were detected at 280 nm. By using cluster analysis and similarity calculation, the 14 batches of rhubarb sample was classified as three types:Rheum tanguticum Maxim.ex Balf., the ordinary Rheum palmatum L.and the inferior Rheum palmatum L. The method was simple and reliable, and it was capable of effectively controlling the quality of rhubarb, and this experiment develops a new application of MEEKC in fingerprint of traditional Chinese medicine.Lastly, Fingerprint of Rheum sample collected from different producing areas was developed by HPLC for its quality control. The separation was carried out on Nucleodur C18 (4.6 mm×250 mm, 5μm) column with mixtures of 0.5% phosphate acid- methanol and acetonitrile as mobile phase in a gradient elution model, and the detection wavelength were at 280 nm. By using cluster analysis and similarity calculation, the 14 batches of rhubarb samples were classified as 3 types, the result is the same to the result of MEEKC classification, which can provide evidence for the possibility of MEEKC in fingerprint of traditional Chinese medicine.