RP-HPLC Determination of Ginkgolic Acid in Ginkgo Biloba L.

Five ginkgolic acids in ginkgo biloba L. were extracted from the sample with methanol under refluxing. The extract was made up to 25 mL and an aliquot of 2 mL was taken and purified by extraction with n-hexane from a solution containing diatomite at pH 2-3. The supernatant was taken and evaporated to dryness rotationally under vacuum. The residue was dissolved with 2 mL of methanol, and 20 μL of the solution were introduced for RP-HPLC analysis by separation on Waters Symmetry-C18 column with the mobile phase of CH3OH-H2O (88+12, containing φ 5% of HOAc). Contents of the 5 acids were determined by DAD at the wavelength of 310 nm. Linear relationships between values of peak area and mass concentration of 5 ginkgolic acids were kept in the definite range, with detection limit (3S/N) in the range of 0.26-1.37 mg·L-1. The value of average recovery found by standard addition method was 99.2%, with value of RSD (n=5) of 6.83%.