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1、Date:2011-05-22Experimentaltitle：Determinationofreducingsugarcontent一DNSmethodPrinciple：Determinationofreducingsugaristhebasicmethodforthedeterminationofsugarcontent.Reducingsugarisfreealdehydeorketonecontainingsugar.Monosaccharidesarereducingsugars,disaccharides
2、andpolysaccharidesarenotnecessarilyreducingsugar.Lactoseandmaltosearereducingsugars,sucroseandstarchnon-reducingsugar.Thesolubilityofthedifferentuseofsugar,youcansamplemonosaccharide,disaccharides,andpolysaccharideswereextracted・(Notreducing)disaccharidesandpolys
3、accharidescanbedouble-acidhydrolysismethod.Outingtodoublesugarandreducingthedegradationintoasinglesugardetermination.Inthesamplewerecalculatedreducingsugarscontent.Contentofreducingsugarwithglucoseinstead.Procedures:CQReagentpreparation:>DNSReagentconfiguration1)
4、InNaOHsolution,byaddingdinitrosalicylicacidsolutionandpotassiumsodiumtitrate2)NaOHsolutionbyaddingcrystallinephenol,addwatertodissolve,andfinallysetthevolume.3)Take(2)69mLanhydroussodiumsulfite6.9g,todissolve4)To(3)into(1),thecompletelydissolved,storedinbrownreag
5、entbottle.Atroomtemperature,place7-10dayslatertouse>GlucosestandardsolutionconfigurationAccuratelyweigh100mgofanalyticalgradeglucose(pre-driedat105°Ctoconstantweight),dissolvedindistilledwaterwithasmallamountofvolumeto1OOmL,refrigeratoruse.QOperationmethods1)Take
6、sixcleantesttubes,addingvariousreagentsinthefollowingorder■LGlucosesolution••11.Distilledwater•••111.DNSreagentX012345Theamountofsugarcontained(mg)00.20.40.60.81.0Distilledwater(ml)10.80.60.40.20DNSreagent3mlDistilledwater(ml)2.5mlHeatingHeat5minutes(90°C)Cooling
7、ImmediatelywiththeflowofcoldwatertocoolOpticaldensity0.761.0861.5222.0532.7833.342(OD)Results:Mixtheabovesolution,eachtubeafterthephotoelectriccolorimeter(510nm)forcolorimetricdeterminationoftheblankcontrolsolutionwithzeroadjustment,recordingtheopticaldensityvalu
8、e.Glucoseconcentrationastheabscissa,theordinateisopticaldensitystandardcurveplotted.Discussion:Inalkalinesolution,thereducingsugarintoeneglycol(1,2-eneglycol).
