Abstract: A new HPLC-ELSD method was established to analyze the content of fructooligosaccharides ［include 1-Kestose (GF-2),Nystose (GF-3) and 1-FFructofuranosylnystose (GF-4)］ in Smallanthus sonchifolius with different processing methods.The content of fructooligosaccharides was determined by HPLC-ELSD.Chromatographic separation was performed on X Amide column (4.6×250 mm,5 μm) with mobile phase of acetonitrile-water (75:25) at a flow rate of 1 mL/min,the drift tube temperature was set at 70 ℃.A good resolution and linear range were obtained under this HPLC-ELSD condition.The linear ranges of GF2,GF3 and GF4 were determined to be 0.406-2.030 mg/mL,0.420-2.100 mg/mL and 0.456-2.280 mg/mL,respectively.The average recoveries were 101.4%(1.53%),99.7%(1.29%),98.6%(2.81%).The developed HPLCELSD method was simple,reliable,accurate and reproducible.It can be used for the quality control of S.sonchifolius. The optimal preparation method was that S.sonchifolius was rinsed with water for 0.5 h,and freeze-dried to powder.

Key words: fructooligosaccharides, HPLC-ELSD, different processing methods, Smallanthus sonchifolius