Abstract: A rapid, reliable and suitable method for the determination of 1-deoxynojirimycin (DNJ) in Morus alba L. leaves has been developed. The DNJ in 100 mg dried leaves was extracted twice with 10 mL aqueous 0.05 mol/L HCl, then derivatized by 6-aminoquinoiyi-N-hydroxysuccinimidyl carbamate （AQC） in K3BO3 buffer （pH 8.5）, and analyzed using a high performance liquid chromatograph equipped with a fluorescence detector. The analyte was eluted with a mobile phase of 0.02 mol/L potassium dihydrogen phosphate buffer-acetonitrile (85∶15, v/v) at the rate of 1.0 mL/min. The derivatized DNJ was well dissolved from the hydrolysis products of AQC. The linearity ranged from 0.5 to 25 mg/L, and the detection limit was 0.02 mg/L （S/N=3）. The content of DNJ in Morus alba L. leaves was 0.12%, the recovery was 96.1%-98.6%.

Key words: 1-deoxynojirimycin (DNJ), fluorescence detection, high performance liquid chromatography (HPLC), Morus alba L. leaves , pre-column derivatization