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Title

Identification of isomeric tropane alkaloids from Schizanthus grahamii by HPLC-NMR with loop storage and HPLC-UV-MS/SPE-NMR using a cryogenic flow probe

Authors
Muñoz, Orlando
Tseng, Li-Hong
Braumann, Ulrich
Spraul, Manfred
Published in Phytochemical Analysis. 2006, vol. 17, no. 2, p. 78-86
Abstract Two fully automated HPLC-NMR methods are reported and compared for the structure elucidation of four isomeric tropane alkaloids from the stem-bark of an endemic Chilean plant, Schizanthus grahamii Gill. (Solanaceae). The first approach interfaced a conventional HPLC column to NMR by means of a loop storage unit. After elution with a mobile phase consisting of deuterated water and standard protonated organic solvents, the separated analytes were momentarily stored in a loop cassette and then transferred one-at-a-time to the NMR flow probe for measurements. The second strategy combined HPLC with parallel ion-trap MS detection and NMR spectroscopy using an integrated solid-phase extraction (SPE) unit for post-column analyte trapping. The SPE cartridges were dried under a gentle stream of nitrogen and analytes were sequentially eluted and directed to a cryogenically cooled flow-probe with an NMR-friendly solvent. The structures of the four isomeric alkaloids, 3alpha-senecioyloxy-7beta-hydroxytropane, 3alpha-hydroxy-7beta-angeloyloxytropane, 3alpha-hydroxy-7beta-tigloyloxytropane and 3alpha-hydroxy-7beta-senecioyloxytropane, were unambiguously determined by combining NMR assignments with MS data.
Keywords Chromatography, High Pressure Liquid/methodsMagnetic Resonance Spectroscopy/methodsMolecular StructurePlant Bark/chemistryPlant Stems/chemistrySensitivity and SpecificitySolanaceae/chemistrySpectrophotometry, Ultraviolet/methodsTropanes/analysis/chemistry
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PMID: 16634283
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BIERI, Stefan et al. Identification of isomeric tropane alkaloids from Schizanthus grahamii by HPLC-NMR with loop storage and HPLC-UV-MS/SPE-NMR using a cryogenic flow probe. In: Phytochemical Analysis, 2006, vol. 17, n° 2, p. 78-86. https://archive-ouverte.unige.ch/unige:6716

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Deposited on : 2010-05-28

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