Compound-Specific Carbon Isotope Ratio Determination of Enriched Cholesterol

Z. K. Guo, A. H. Luke, W. P. Lee, D. Schoeller

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

On-line gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) was evaluated for use in stable isotope studies of human cholesterol metabolism. Calibration curves were constructed by analyzing underivatized and TMS-cholesterol over a range of 13C abundances from natural abundance to 0.05 mol of [3,4-13C]cholesterol per mole of unlabeled cholesterol (δ13C -24 to 270%o). The calibration curves were highly linear (r2 = 0.99) with slopes of 0.98 and 0.88 for underivatized and TMS-cholesterol, respectively. Higher precision of 13C/12C ratio determination was obtained using TMS-cholesterol, with a detection limit (2 SD) of 0.3%o or 0.004 mol% of [3,4-13C]-cholesterol. By comparison standard GC/MS had a detection limit of 0.06 mol% for [3,4-13C]cholesterol. A 57-day study of cholesterol elimination was conducted in one human subject with oral administration of 50 mg of [3,4-13C]cholesterol. Peak enrichment was 9%o above baseline (40 times the detection limit) and could be followed for 40–50 days. The results indicate that GC/C/IRMS provides 15-fold lower detection limits for [3,4-13C]-choleseterol than GC/MS and is useful for human studies of cholesterol metabolism.

Original languageEnglish (US)
Pages (from-to)1954-1959
Number of pages6
JournalAnalytical Chemistry
Volume65
Issue number15
DOIs
StatePublished - Aug 1 1993

ASJC Scopus subject areas

  • Analytical Chemistry

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