Abstract:

A high-performance liquid chromatography (HPLC) method for separating and determining 10 standard coumarins was developed, and was used to determine coumarins in Tomentose Pummelo Peel (Exocarpium Citri Grandis) collected from ten areas in Huazhou County. Ten standard coumarins were as follows: hymecromone, coumarin, 7-hydroxycoumarin, psoralen, 6-methylcoumarin, 5,7-dimethoxycoumarin, bergapten, imperatorin, isoimperatorin and bergamottin. Samples were chromated using reversed-phase Nucleosil C18 column (150 mm×4.6 mm, 3 μm), and the mobile phases A, B, C were water, methanol and acetonitrile respectively. Triple gradient elution started at 0.3 ml/min and proceeded at 0.3－1.0 ml/min. Operation conditions were set as follows: column temperature 35 ℃, detection at 315 nm. Results showed that linear calibration of ten standard samples were within 0.078－15.000 μg/ml with correlation (r) 0.999－1.000. Relative standard deviation (RSD) of retention time and peak area were both below 3.466% in five consecutive tests or repeated tests during 48 h. Except 6-methylcoumarin and 5,7-dimethoxycoumarin, totally 8 coumarins were detected in all of the ten Tomentose Pummelo Peel samples with significant difference. No.7 sample was the richest in coumarins with coumarin content at 0.138% dried mass (DM) and isoimperatorin content at 0.123% DM. It indicated that coumarin and isoimperatorin were main coumarins in Tomentose Pummelo Peel.

Key words: HPLC, Tomentose Pummelo Peel, coumarin