Determination of Emodin in Different Processed Rhubarb by HPLC

An HPLC method to determine the emodin in different processed rhubarb was established with a Hypersil Gold C_(18)(150 mm×4.6 mm,5 μm) column.The mobile phase was composed of methanol and 0.05% H_3PO_4 solution(85∶15,V/V),the flow rate was 1.0 mL/min,the detection wavelength was 254 nm,and the column temperature was room temperature.The calibration curve was linear in the concentration range of 4.79~47.9 μg/mL with correlation coefficient of 1.000. The mean recovery of the method was 98.56%,RSD was(1.30%)(n=5).The concentrations of emodin in Radix et Rhizoma Rhea and its processed products are as follows,0.401% in Radix et Rhizoma Rhei,0.669% in ripe Radix et Rhizoma Rhei,0.512% in winy Radix et Rhizoma Rhei,and 0.348% in acetic Radix et Rhizoma Rhei,respectively.The results showed that the content of emodin in Radix et Rhizoma Rhei was different from that in the corresponding processed drugs.