Abstract:Objective:To establish a quantitative method for the content determination and monosaccharide composition analysis of Konjac glucomannan(KGM)in Konjac refined powder by pre-column derivatization high performance liquid chromatographic method (HPLC). Method: The two derivatives combined reducing monosaccharides with l-phenyl-3-methyl-5-pyrazolone (PMP) were separated by reverse-phase HPLC using a developed fragment gradient elution process, and monitored by ultraviolet detector at 250 nm. The broad reagent peak of PMP was separated very well from all the PMP-sugars,and good separation was achieved for derivatives of mannose and glucose. The quantitative methods of two reducing monosaccharides were studied by the method combined internal and external standard; while the KGM content in Konjac refined powder was determined. Result: Linearity of glucose was good (r = 0.9990) in range of 1.002-8.016 nmol;while mannose (r = 0.999 4) in range of 1.001-8.008 nmol.The average recovery of this method was 98.1 % , RSD of repeatability was 1.72% . KGM content in Konjac refined powder was 79.5% , ratio of glucose to mannose in KGM was 1:1. 51. Conclusion: This method is a sample, convenient and rapid method that can determine KGM content and analyze monosaccharide compositions in KGM, which will be helpful to quality assessment of Konjac refined powder.