[The determination of konjac glucomannan in konjac refined powder and monosaccharide compositions by HPLC].
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).


METHODS
The two derivatives combined reducing monosaccharides with 1-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.


RESULTS
Linearity of glucose was good (r = 0.9990) in range of 1.002-8.016 nmol; while mannose (r = 0.9994) 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.


CONCLUSIONS
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.
Yuan
Zhong-hai
ZH
Department of Clinical Examination, Jilin Military Medical College, Fourth Military Medical University, Jilin 132011, China. yuanzhonghai806@sohu.com
Wu
Dao-cheng
DC
Zhao
Yan
Y
Wu
Hong
H
Li
Xiao-ye
XY
D031056:Amorphophallus / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000737:chemistry; D008351:Mannans / Q000032:analysis* / Q000737:chemistry; D008358:Mannose / Q000737:chemistry; D009005:Monosaccharides / Q000032:analysis*; D010946:Plants, Medicinal / Q000737:chemistry*; D011208:Powders / Q000737:chemistry
D008351:Mannans; D009005:Monosaccharides; D011208:Powders; C022901:(1-6)-alpha-glucomannan; D005947:Glucose; D008358:Mannose