Direct (13)C NMR detection in HPLC hyphenation mode: analysis of Ganoderma lucidum terpenoids

J Nat Prod. 2012 May 25;75(5):876-82. doi: 10.1021/np200915c. Epub 2012 Apr 19.

Abstract

Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments is indubitable in simplifying structural elucidations. In the current study, we demonstrated direct (13)C NMR detection of triterpenoids from a Ganoderma lucidum extract in hyphenation mode. The combined advantage of a cryogenically cooled probe, miniaturization, and multiple trapping enabled the first reported application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 μg of a prefractionated triterpenoid mixture, six trappings, and an acquisition time of 13 h resulted in spectra with adequate signal-to-noise ratios to detect all C-13 signals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid / methods
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Reishi / chemistry*
  • Solid Phase Extraction / methods*
  • Spores, Fungal / chemistry
  • Triterpenes / analysis*
  • Triterpenes / chemistry
  • Triterpenes / isolation & purification

Substances

  • Triterpenes