Establishment Of A Method For Liquid Chromatography–Mass Spectrometry Determination Of Trace Carbohydrate Compounds In Biological Systems

Carbohydrate compounds have various structures and play important roles in various life pr^ocesses.The development of a simple,accurate,sensitive and high-throughput method for qualitative and quantitative analysis of sugars will help us to have a deeper understanding of the biological functions of sugars.In this paper,six aldose compounds,xylose,ribose,glucose,galactose,maltose and maltotriose,are used as the research objects,which represent five-carbon monosaccharides,six-carbon monosaccharides,disaccharides and trisaccharides,respectively.Liquid chromatography-tandem mass spectrometry（LC-MS/MS）method for the determination of glucose in human saliva and urine and five-carbon monosaccharide,six-carbon monosaccharide,disaccharide and trisaccharide compounds in fermented corn stover.This method has high sensitivity,high accuracy,good repeatability and fast detection speed,which enables us to better monitor glucose levels in body fluids,and helps us to better understand the fermentation behavior of microorganisms.LC-MS/MS method combined with precolumn derivatization with dibenzylamine was used to determine trace glucose in human saliva and urine.Firstly,dibenzylamine（DBA）was used as pre-column derivatization reagent,and the optimal derivatization conditions of DBA and glucose were determined by single variable method.Then,saliva and urine samples were treated by solid phase extraction method.Finally,glucose content in saliva and urine was analyzed by the established analytical method.The results showed that the linear correlation coefficient R² of the method was greater than 0.9990,the limit of detection（LOD）was 0.10ng/mL,and the limit of quantification（LOQ）was 0.35 ng/mL.The spiked recoveries of glucose in saliva ranged from 97.80%to 104.50%with RSD of 0.39%to 1.35%.The recovery range of glucose in urine was 93.90%-98.70%with RSD of 0.27%-2.46%.The same sample was tested six times over five days,the iner and intra-day accuracy of the quantitative method ranged from 91.97%to 102.01%,and the iner and intra-day precision of the method ranged from 0.27%to 3.21%,both less than 10%.LC-MS/MS method combined with precolumn derivatization with dibenzylamine was also used to determine aldosaccharide compounds in samples collected from fermentation processes.Firstly,the conditions of derivatization reaction of glucose,xylose,ribose,galactose,maltose,maltotriose and DBA were optimized.The aldosaccharide compounds in the fermented corn stover were then extracted by ultrasonic water extraction.Finally,the established LC-MS/MS method was used to determine the contents of five-carbon monosaccharides,six-carbon monosaccharides,disaccharides and trisaccharides in the fermented corn stover with high sensitivity and satisfactory recovery.The limits of detection（S/N=3）and limits of quantification（S/N=10）of glucose,galactose,maltose,and maltotriose were 0.10 ng/mL and 0.35 ng/mL,respectively.The values of xylose and ribose were 7 ng/mL and 20 ng/mL,respectively.The intraday accuracy of the method ranged from94.32 to 103.72%,and the interday precision ranged from 92.25 to 110.75%,and the intraday precision of the method ranged from 0.64 to 6.02%,and the interday precision ranged from1.06 to 9.12%.2.67μg/kg of glucose,22.08μg/kg of xylose or 11.98μg/kg of ribose,0.31μg/kg of galactose,0.98μg/kg of maltose,and 1.08μg/kg of maltotriose were separately detected in sample of fermented corn stalk.