Studys On HPLC Fingerprint Of Soybean Isoflavons

Recently soybean isoflavones are having been one of the most popular phytomedicines. In the paper, the soybean isoflavones in 25 samples were extracted and determined with different analytical methods, such as ultraviolet spectrum(UV) , high performance liquid chromatography(HPLC) and liquid chromatography-mass spectrum(HPLC-MS). The immanence character of soybean as plant medicine were researched by determining the content and fingerprint of isoflavones. The establishment of method on different samples is valuable for quality control of soybean isoflavones. It is also significant for the further research on soybean.The part dealt with the extraction technology of isoflavones from soybean by ethanol.Using the orthogonal design, the optimum extracting conditions were obtained after the study of the effects of ethanol concentration, solvent volume, extracting time and frequency. A quick analysis method for the determination of total isoflavones in soybean was established based on the first order derivative UV spectrophotometry at 271 nm. The method is simple, accurate, rapid and reliable for determination of isoflavones in soybean, and it provides a gist of appraising the content about soybean isoflavones.The alcohol extracts of soybean were analyzed by RP-HPLC to acquire the chromatographic fingerprints. The gradient elution mode was applied in chromatographic separation .AC₁₈ column (4.6 mm × 250 mm, 5 μm) was used with the mobile phase being ice acetic acid water solution(pH=3.2)-methanol, flow rate being 0.6 mL / min, detectingwavelength at 261 ran, the column temperature being at room temperature. The chemical components including geinstein were separated.23 chemical variables were obtained from soybean. All samples were identified with hierarchial clustering analysis and divided into 3 grades. The result shows that the distinction between different samples was visible. The similarity was determined by the software of Traditional Chinese Medicine fingerprint. Meanwhile, the main components were assigned in accordance with the m/z -, UV and the retention time of peaks.The aim of this part is to improve the reproducibility of retention time on the fingerprint of soybean isoflavones by HPLC. Under the chromatographic condition of soybean isoflavone fingerprint, 5 substances as standard sample are used to establish the calibration curve and to calculate the constant A and B. The shift of retention time of the fingerprint in which peak area is more than 1.5% is corrected by constant A and B. The absolute error of retention time is diminished from 5.868 min to 0.854 min after calibration. The results show that the method is a good way to correct the shift of retention time for chromatographic fingerprints obtained from different Cis columns or different HPLC systems. In addition the calibration results improve the reproducibility greatly in order to apply in different laboratories conveniently.