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简介：ＣｏｍｐａｒｉｓｉｏｎｏｆＦＡＢａｎｄＭＡＬＤＩＭａｓｓＳｐｅｃｔｒｏｍｅｔｒｙｏｆＧｉｎｓｅｎｏｓｉｄｅｓ￥ＺｈｏｕＹｕ；ＬｉｕＺｈｉｑｉａｎｇ；ＳｏｎｇＦｅｎｇｒｕｉ；ＬｉｕＳｈｕｙｉｎｇ；ＬｉＸｉａｎｇｇａｏ；ＹｉｎＪｉａｎｇｙｕａｎ（１Ｃｈａ...

简介：Thenegativeionfastatombombardment(NIFAB)massspectraofmono-,di-saccharidesandglycosidesusingphenylboronicacid(PBA)asreagenthavebeenstudied.Intheionsource,PBAreactsstereospecificallywiththemoleculescontainingcis-vicinalglycolstoformcharacteristicions,fromwhichthestereo-isomersofsaccharidescanbedefinitelydistinguished.Disaccharidesandglyco-sideswithβ-glycosidiclinkageseemtobeunfavorabaletoreactwithPBA,therefore,bycomparisonoftheabundancesofthecharacteristicions,theconfigurationoftheglycosidiclinkageinthesecompoundsmaybeinferred.

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简介：Itwasfoundthatphosphorylationofsmallpeptidecouldimprovethesensitivityinmassspectrometry.DensityfunctionaltheorycalculationsshowedthattheenergyfortheprotonationofN-(O,O′-dimethyl)phosphorylglycylglycineislowerthanthatofglycylglycine.Thesecouldhelptounderstandingtheexperimentalresults.

简介：Chloramphenicolisanantibioticandoneofthepotentialcontaminantsinhoney.Solid-phaseextractionisthekeypretreatmentprocedureforanalysisofchloramphenicolinhoney.Inthiswork,anon-linepretreatmentliquidchromatography-tandemmassspectrometersystemforsensitive,reliableandhigherthroughputanalysiswasdeveloped.Withthemethylcellulose-immobilizedreversed-phasecolumn,sugarsinahoneysamplewereefficientlyremovedin1min.Asaresult,thelimitofquantitationofchloramphenicolwas20pg/mL(0.2μg/kghoney).

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：Anewformulawaspresentedforlocatingdoublebondpositionindodecenols,tetrade-cenols,hexadecenolsandtheiracetates,basedonmassspectraldataofdimethyldisulfidederivatives.Inthisprocedure,molecularionandbasepeakionwereutilizedascharacteristicparameterstoidentifythepositionalisomers.Themethodwastestedwithmassspectraof25dimethyldisulfldederivativesofmono-unsaturatedacetatesandalcohols,andtheoriginaldouble-bondpositionineachisomerwaslocatedunambiguously.

简介：Inthiswork,areliableandsensitivemethodfordetectingpolybrominateddiphenylethers(PBDEs)hasbeendevelopedbythecombinationofliquid–liquidextractionandgaschromatography–massspectrometry.PBDEswereextractedfromalargevolumeofwaterbyliquid–liquidextractionandpurifiedbysilicagelchromatography.Inordertoreducethedeviation,dibromobiphenylwasexploitedastheinternalstandardtominimizedifferencesamongtheinjections.Thequantificationwasperformedusinganexternalstandard.Goodlinearcorrelationcoefficients(>0.991)andawidelinearityrange(1.0–500.0ng/L)indicatedthesteadinessoftheproposedmethod.Moreover,thesatisfactoryrecovery(>75%)suggestedthatsuccessfuldeterminationofPBDEsinriverwaterhadbeenachieved.Furthermore,thedeductionbehaviorofPBDEsinriverwatercouldbeinferredaccordingtotheresults.

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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：InordertoidentifythepotentialnephrotoxiccompoundsintraditionalChinesemedicineLithospermumerythrorhizon,itwasseparatedintoserialfractionsaccordingtotheirpolarities.Aninvitromethodwasutilizedtodeterminethenephrotoxicityofthesefractionswiththehelpoffluorescenceimageanalysis.Asaresult,theprimaryfractionA05anditssecondaryfractionsC06'C09andC12'C14werefoundtohavesignificanttoxicitytoLLC-PK1cellline,asdeterminedbythesurviveratelessthan20%aftertheyweretreatedwiththesefractions.Thesepotentialnephrotoxicfractionswerefurtheranalyzedbymultistageandhighresolutionmassspectrometry.Themaincompoundsinthesefractionsweretentativelyidentifiedtobeacetylshikonin,isobutyrylshikonin,β,β'-dimethyla-cryloylshikonin,andisovalerylshikonin,whichmaybringnephrotoxicity.