HPLC Determination of Nigranoic Acid in Fructus Schisandra with Matrix Solid Phase Dispersion

A method of determination of nigranoic acid in fructus schisandra by HPLC with matrix solid phase dispersion was proposed.The sample was homogenized with silica gel in the ratio of 1 to 4 by mass,and packed into SPE-column.It was then eluted with pure dichloromethane at a flow rate of 5 mL·min-1 to remove co-existing interfering substances.Nigranoic acid was eluted from the column with mixed solution of dichloromethane and acetone (9+1),and then dried by blowing with N2-gas.The eluate was separated on ZORBAX Stable Bound C18 (4.6 mm×100 mm,1.8 μm) rapid column,using mixed solution of methanol and water (82+18) as mobile phase,and determined by evaporation light scattering detector.Linear relationship between the peak area and the mass concentration of nigranoic acid was obtained in the range of 2.0~400.0 mg·L-1,with detection limit (3S/N) of 20 μg·L-1.The proposed method was used in the analysis of fructus schisandras,giving RSD′s (n=7) less than 2.0%.The values of recovery found by standard addition method were in the range of 96.8%-101.5%.