Direct Chiral Analysis of Complex Mixtures by Fourier Transform Molecular Rota;onal Resonance (FT-MRR) Spectroscopy

LucaEvangelis.,NathanSeifert,LorenzoSpada,andBrooksH.Pate,DepartmentofChemistry,UniversityofVirginia

Ma@Muckle,Jus.nNeill,andRogerReynolds,BrightSpec,Inc.,Charlo<esville,VA

Acknowledgements:

ThisworksupportedbyBrightSpec,NSFMRICHE-0960074,UniversityofBologna(LS),andERS/EUMarieCuriePostdoctoralResearchFellowshipProgram(LE)

Introduc)onMolecular rota.onal spectroscopy provides a spectral signaturewith extreme sensi.vity to themassdistribu.on(3Dstructure)ofthemolecule. Instrumentsformeasuringrota.onalspectrausingpulsedjetsourcesofferhighsensi.vityandhighspectralresolu.on.Asaresult,itispossibletoperformdirectquan.ta.ve analysis of complex mixtures without chromatographic separa.on. For samples thatincludechiralmolecules,rota.onalspectroscopycaniden.fydiastereomersofmoleculeswithmul.plechiralcentersand,withfundamentaladvancesinthepasttwoyears*,canperformenan.omericexcessmeasurementsonthediastereomers.

BuchuOil(betulina)

BuchuOil(crenulata)

Molecule %

Obs AssignedinMixture

PreviousMWAnalysis

ReferenceSpectrum

Diosphenol 22 • •

Isomethone 20 • •

4-diosphenol 19 • •

Limonene 12 • •

Menthone 10 • •

1,8-cineole 4 • •

Z-8-mercaptomenthone 2 • •

Pulegone 1 •

E-isopulegone 0.5 • •

E-8-mercaptomenthone 0.5 • •

Linalool 0.5 •

α-pinene 0.4 • •

Z-isopulegone 0.4 • •

β-pinene 0.3 • •

Piperitone 0.06 • •

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Ini)alAnalysisofBuchuOilComposi)on

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BroadbandRota)onalSpectrumoftheVola)leHeadSpace(65oC)

Enan)omericExcessMeasurementofMenthoneDirectlyintheMixtureusingThreeWaveMixingFT-MRRSpectroscopy

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Iden)fica)onoftheDiastereomersof8-mercaptomenthone

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Z-8-mercaptomenthone E-8-mercaptomenthone