简介：Inthisstudywesystematicallyanalyzedtheelutionconditionoftrypticpeptidesandthecharacteristicsofidentifiedpeptidesinreversephaseliquidchromatographyandelectrospraytandemmassspectrometry(RPLC-MS/MS)analysis.Followingproteindigestionwithtrypsin,thepeptidemixturewasanalyzedbyon-lineRPLC-MS/MS.Bovineserumalbumin(BSA)wasusedtooptimizeacetonitrile(ACN)elutiongradientfortrypticpeptides,andCytochromeCwasusedtoretestthegradientandthesensitivityofLC-MS/MS.Thecharacteristicsofidentifiedpeptideswerealsoanalyzed.Inourexperiments,thesuitableACNgradientis5%to30%fortrypticpeptideelutionandthesensitivityofLC-MS/MSis50fmol.Analysisofthetrypticpeptidesdemonstratedthatlonger(morethan10aminoacids)andmulti-chargestate(+2,+3)peptidesarelikelytobeidentified,andthehydropathicityofthepeptidesmightnotberelatedtowhetheritismorelikelytobeidentifiedornot.Thenumberofidentifiedpeptidesforaproteinmightbeusedtoestimateitsloadingamountunderthesamesamplebackground.Moreover,inthisstudytheidentifiedpeptidespresentthreetypesofredundancy,namelyidentification,charge,andsequenceredundancy,whichmayrepresslowabundanceproteinidentification.

简介：Massspectroscopiccharacteristicsofphosphorylaminoacidswerestudiedindetailbypositiveandnegativeelectrosprayionizationmassspectrometry(ESI-MS)inconjunctionwithtandemmassspectrometry(MS/MS).BesidesN-diisopropyloxyphosphorylaminoacids(N-DIPP-AA),O-phospho-andO-diisopropyloxyphosphorylaminoacids(O-DIPP-AA)werestudiedandcomparedtoN-DIPP-AA.Thefragmentationpathwaysof[M+H]^+,[M+Na]^+and[M-H]^-ionsofphosphorylaminoacidsweresummarized.Inadditiontoseveralsimilarpatterns,eachofthemshoweditscharacteristicfragmention.

简介：Serine,oneofthenonessentialaminoacids,isofprincipalinterestbecauseofitscapabilitytoformmagic-numberionicclusters,whichprovidearemarkablepreferenceforhomochirality.WithL-asparticacidastheprecursor,thisstudyprovidesexperimentalevidenceforserineformationinweakacidifiedaqueoussolutionsinthepresenceofiron,withexposuretosunlight,whichsimulatesthenaturalconditionsoftheprebioticaqueousenvironment.Theresultantmixtureisdirectlyanalyzedviadesorptionelectrosprayionizationmassspectrometry(DESI-MS),withoutanysamplepreseparation.Theserinemonomerissuccessfullydetectedasprotonatedmolecules,givingapeakatm/z106,whichisconfirmedbytheMS/MSfragments.Protonatedserineoctamer(m/z841)isalsoobservedwithsignificantabundanceintheMSspectraandisconfirmedbytheMS/MSdata,whichshowstheformationoftheserineoctamerbyasynthesizedserineintheresultantmixture.ItisalsofoundthattheserineoctameryieldedequivalentabundanceintheDESImassspectrainawidepHrange(pH=1-5),andthatexistenceofferroussaltandsunshineareessentialfortheconversionofasparticacidtoserineintheacidicwatersolution.

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简介：Si-Miao-Wan(SMW),atradiationalChinesemedicinalformulaconsistingofAtractylodisRhizoma,PhellodendriChinensisCortex,CoicisSemen,andAchyranthisBidentataeRadix,hasbeenusedforthetreatmentofgoutandgoutyarthritisformanyyears.Inthepresentstudy,aliquidchromatographyquadrupole-time-of-flightmassspectrometry(LC-Q-TOF/MS)methodwasestablishedtoidentifythemultipleconstituentsofSMWanditsmetabolitesinratbiologicalsamplesafteroraladministration.Atotalof48compoundsinSMW,including21alkaloids,12organicacids,2terpenes,3lactones,2phytosterols,and8othercompounds,weretentativelycharacterizedwiththediagnostic-ionfilteringstrategy.BasedonthediagnosticionsappliedtoidentifycompoundsinSMW,28prototypecompoundsand10metaboliccompoundsweredetectedinthebiologicalsamples.ThiswasthefirstcomprehensivedrugmetabolisminvestigationofSMWinrats.Thedevelopedmethodcouldbeausefulmeansforidentifyingthemulti-componentsinSMWandthemetaboliccomponents.TheresultsmayhelpexplorethepossiblemetabolicprocessesandmechanismofactionforSMWinvivo.

简介：TocharacterizeandidentifymultipleconstituentsinDanhonginjection(DHI),afastultra-highperformanceliquidchromatographycoupledtoelectrosprayionizationquadrupoletime-of-flighttandemmassspectrometry(UHPLC-ESI-QTOF/MS)methodwasestablishedandvalidatedinthepresentstudy.Atotalof63compounds,including33phenolicacids,2C-glycosylquinochalcones,6flavonoidO-glycosides,4iridoidglycosides,6organicacids,5aminoacids,and3nucleosides,wereidentifiedortentativelycharacterized.Inconclusion,theUHPLC-ESI-QTOF/MSmethodisusefulandefficientforin-depthstructuralelucidationofchemicalcompoundsincomplexmatricesofherbalmedicinessuchasDHI.

简介：Thepresentstudywasdesignedtodevelopandvalidateasensitiveandreliableultrahighperformanceliquidchromatographycoupledwithquadrupoletime-of-flightmassspectrometry(UPLC-QTOF/MS)methodtoseparateandidentifythechemicalconstituentsofQixueShuangbuTincture(QXSBT),aclassictraditionalChinesemedicine(TCM)prescription.UndertheoptimizedUPLCandQTOF/MSconditions,56componentsinQXSBT,includingchalcones,triterpenoids,protopanaxatriol,flavonesandflavanoneswereidentifiedandtentativelycharacterizedwithinarunningtimeof42min.Thecomponentswereidentifiedbycomparingtheretentiontimes,accuratemass,andmassspectrometricfragmentationcharacteristicions,andmatchingempiricalmolecularformulawiththatofthepublishedcompounds.Inconclusion,theestablishedUPLC-QTOF/MSmethodwasreliableforarapididentificationofcomplicatedcomponentsintheTCMprescriptions.