[Study on retention time shift correction of fingerprint chromatograms of soybean isoflavones]

A method has been developed to improve the reproducibility of retention time on the fingerprint chromatograms of soybean isoflavones by high performance liquid chromatography (HPLC). Alltech C18 column and Diamonsil C18 column were used on LC-10AT system and Aglient 1100 system respectively, the mobile phase being acetic acid solution (pH 3.2)-methanol, flow rate being 0.6 mL/min, detection wavelength at 261 nm. All experiments were performed at room temperature. Under the chromatographic conditions of soybean isoflavone fingerprints, five substances as standards were used to establish the calibration curves. The shift of retention time of the fingerprint chromatogram in which peak area percentage is more than 1.5% was corrected by linear equation. The results show that the absolute error of retention times is diminished from 5.868 min to 0.854 min after calibration. This method is a good way to correct the shift of retention time for chromatographic fingerprints obtained from different C18 columns or different HPLC systems. In addition, the calibration results improve the reproducibility greatly and can be applied in different laboratories conveniently.