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High-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are analytical methods most commonly used presently to quantify components of Chinese herbal medicine. Working together, HPLC and CE can advantageously complement each other and broaden the field of analysis of Chinese herbal medicine. In this work, analyses of Gardeniae Fructus, applied to five relevant preparations and Peony Combination using HPLC and CE have been studied. The practical aspects and experimental factors of analyses by HPLC and CE have been compared and discussed. Five standard components of Gardeniae Fructus can be separated by micellar electrokinetic chromatography (MEKC). The analytical conditions included a buffer solution containing 40mM borate, 60mM sodium dodecyl sulfate (SDS) and 5M urea (pH 9.48) and the analytical voltage set at 20kV. The wavelength of the UV-VIS spectrometer was fixed at 240nm for the detection of genipingentiobioside (GN), geniposide (GP), gardenside (GD) and geniposidic acid (GPA), and for the detection of crocin (CR) the wavelength was fixed at 440nm. Within 30 minutes, the five compounds could be quantified. The linearity range of the quantified concentration of all five compounds could reach 2 orders, and the detection limits fell between 2.67 and 5.75 μg/ml. The relative standard deviations of the migration times and the areas-were all smaller than 2.0% (n=6). The working analytical procedure can also be applied to the analyses of five relevant preparations. Peony Combination contains nine component herbs, and 27 chief constituents were selected from all constituents of the formula. In this work,the analytical methods for Peony Combination using HPLC and CErespectively have been developed. In the respect of HPLC, the reverse-phase HPLC was used, and the elution system included dynaulic phase (A) (30mM KH2P04; pH3.25 adjusted by adding 0.01% H3P04) and dynamic phase (B) (H2O/CH3CN=20/80, V/V). With 5C18-MS separation column, the 27 chiefcomponents of Peony Combination were all quantified in 70 minutes by UV- VIS detection at 230nm and 275nm, respectively. The linearity range of the quantified concentration could reach 2 orders, and the detection limits fell between 0.38 and 2.77 μg/ml. The relative standard deviations of the migration times and the areas were all smaller than 2.3% (n=6). In the respect of CE, gradient-MEKC (g-MEKC) has been developed to analyze Peony Combination. The analytical conditions used in this study included: the primary buffer solution contained 20mM borate and 40mM sodium cholate (SC) (pH9.75), and the secondary buffer solution was acetonitrile (AcCN). The analytical voltage was set at 20kV, and the length of capillary tube was 11Ocm. The wavelength of the UV-VIS spectrometer wasfixed at 230nm and 275nm respectively to detect 17 chief constituents. The linearity range of the quantified concentration could reach 2 orders, and the detection limits fell between 3.23 and 17.28 μg/ml. The relative standard deviations of the migration times and the areas were all smaller than 3.0% (n= 6). The basic theory and the proposed mechanism of separation and analysis of g-MEKC are also discussed in this study. From the experimental results, it is concluded that for the analysis of Chinese herbal medicine, HPLC and CE possess some advantages and some disadvantages in terms of the analytical time, the stability of baseline, the order of movements of compounds and the numbers of theoretical plates of each compound, respectively. HPLC and CE complement each other in analysis of Chinese herbal medicine.
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