Résumé
A method was developed for the determination of furocoumarin compounds(psoralen, oxypeucedanin, imperatorin, isoimperatorin) in traditional Chinese medicine samples by dispersive liquid-liquid microextraction(DLLME) coupled with high performance liquid chromatography and the relation of sample solution volume, sediment phase volume with enrichment factors was deducted. Some important parameters that influenced the extraction efficiency were optimized: 50 μL carbon tetrachloride and 300 μL acetonitrile were rapidly injected into 1.5 mL sample solution containing 2.5%(w/V) NaCl. After centrifugation at 3500 r/min for 3 min, the sedimented CCl_4 phase was pumped and recorded the volume, then dissolved with methanol and injected into the HPLC for analysis. Under the optimum conditions, a good linear relationship was obtained in the range of 0.006 6.00 mg/L of both psoralen and oxypeucedanin and 0.006-12.0 mg/L of both imperatorin and isoimperatorin. The limits of detection were 1.0-3.0 μg/L(S/N=3). The relative standard deviations were 2.3%-5.4%(n=5). The enrichment factors ranged from 12.6 to 38.5 folds. The average recoveries ranged from 97.5% to 114.8%. The four kinds of furocoumarin compounds in Radix Angelicae dahuricae and Yuanhu Zhitong tablet were determined by the proposed method with satisfactory results.