Objective: To establish a high performance liquid chromatographic (HPLC) amalgamated to double UV waves method for simultaneous determination of loganin and paeonol in Liuwei Dihuang pills.
Method: A HPLC method was developed. The separation was carried out on a Agilent Zorbax SB C18 column (5 microm, 4.6 mm x 250 mm). The mobile phase consisted of water (A) and acetonitrile (B) with linear linear gradient elution [0-8 min, (B) from 1% to 12%; 8-21 min, B keep 12%; 21-40 min, (B) from 12% to 90%; 40-50 min, B keep 90% for 10 min]. The detection was Photodiode Array with the detection wavelengths were at 236 nm and 274 nm. The column temperature being 30 degrees C and the flow rate was 1.0 mL min(-1). Extracting the chromatergraph from 274 nm and 236 nm, we amalgamated the two chromatographs by matlab programmed.
Result: The calibration curves of loganin and paeonol were linear in the ranges of 0.0362-1.09 microg (r =0. 9998) and 0.0450-1.35 microg (r =0.9998), respectively. The average recoveries of loganin and paeonol were 97.3% (RSD 1.4 %) and 103.0% (RSD 1.9%), respectively. Three different batches of Liuwei Dihuang pills were determined with this method.
Conclusion: This is a more convenient, reasonable and credible quality control method for the traditional Chinese medicine.