Abstract: Contents of five flavanones such as narirutin,naringin,hesperidin,naringenin and hesperetin as well as nobiletin in five citrus medicinal resources were analyzed.Huajuhong,Chenpi (dried tangerine peel),Qingpi,Juluo and Juhe were extracted with 70% ethanol aqueous solution;extract solution was diluted and then cleaned and concentrated by C₁₈ solid phase extraction column.A reverse-phase HPLC gradient elution with 0.5% acetic acid (aq.) and methanol as mobile phase was developed for separation;a diode array detector (DAD) was hyphenated to scan UV spectra for the qualitative analysis;quantitation was achieved respectively at 283,285,290 and 335 nm.Under above conditions,the six flavonoids were base-isolated;the external standard method for quantitation showed good linear correlation (R²≥0.999 8);recovery rate was between 95.83%-103.56%;the relative standard deviation was between 2.90%-8.78%.The results of sample content analysis showed that Qingpi had the highest concentration of narirutin 10.49 mg/g,naringenin 0.327 mg/g and hesperetin 0.129 mg/g;Chenpi had the highest concentration of hesperidin 10.78 mg/g and nobiletin 1.74 mg/g;Huajuhong had the highest concentration of naringin 19.20 mg/g.This method is suitable for accurate qualitative and quantitative detection of flavonoids in citrus medicinal resources.

Key words: citrus medicinal resources, high performance liquid chromatography, solid phase extraction, nobiletin, flavanone