Stable isotope methods for the study of beta-carotene-d8 metabolism in humans utilizing tandem mass spectrometry and high-performance liquid chromatography.

This report presents analytical methods for the isolation and quantification of all-trans-beta-carotene-d8 in human plasma following a 73 mumol oral dose. Retinol-d4 derived from beta-carotene-d8 was also determined in the same plasma. Plasma samples drawn over a 24 day period were analyzed. beta-Carotene and retinol were isolated and purified for analysis using a solid phase extraction protocol with aminopropyl-bonded silica sorbent. Ratios of beta-carotene-d8/beta-carotene were determined using reversed-phase HPLC with spectrophotometric detection, which fully resolved the isotopomers, and by tandem mass spectrometry (MS/MS) with electron ionization. Results obtained from MS/MS and HPLC analysis showed close agreement and demonstrated improved selectivity relative to analysis using a single mass analyzer. Retinol-d4 was converted to its tert-butyldimethylsilyl ether and analyzed by gas chromatography/mass spectrometry using selected ion monitoring. The ability to resolve the beta-carotene isotopomers by HPLC makes it feasible for investigators without mass spectrometers to investigate the dynamics of absorption and metabolism of beta-carotene-d8 in humans.

[1]  J. Brenna,et al.  Study of β‐Carotene Metabolism in Humans Using 13C‐β‐Carotene and High Precision Isotope Ratio Mass Spectrometry , 1993 .

[2]  A. Clifford,et al.  An improved protocol for determining ratios of retinol-d4 to retinol isolated from human plasma. , 1993, Analytical chemistry.

[3]  R. Yamauchi,et al.  Products formed by peroxyl radical oxidation of .beta.-carotene , 1993 .

[4]  J. C. Smith,et al.  Separation and identification of carotenoids and their oxidation products in the extracts of human plasma. , 1992, Analytical chemistry.

[5]  H. Furr,et al.  Metabolism of carotenoid analogs in humans. , 1992, The American journal of clinical nutrition.

[6]  J. Bulux,et al.  Plasma response to oral beta-carotene in Guatemalan schoolchildren. , 1991, The American journal of clinical nutrition.

[7]  F. Regnier,et al.  Stoichiometric displacement of solvent by non-polar solutes in reversed-phase liquid chromatography. , 1985, Journal of chromatography.

[8]  M. Sporn,et al.  Can dietary beta-carotene materially reduce human cancer rates? , 1981, Nature.

[9]  A. L. Harkness,et al.  Mass spectrometric comparison of ordinary and fully deuterated α‐ and β‐carotene , 1972 .

[10]  D. Goodman,et al.  The intestinal absorption and metabolism of vitamin A and beta-carotene in man. , 1966, The Journal of clinical investigation.

[11]  H. R. Bergen,et al.  Synthesis of deuterated -carotene , 1989 .

[12]  M. Rose.  METASTABLE ION TECHNIQUES FOR THE ANALYSIS OF CAROTENOID ISOMERS , 1982 .

[13]  H. Budzikiewicz.  MASS SPECTRA OF CAROTENOIDS - LABELLING STUDIES , 1982 .

[14]  R. Blomstrand,et al.  Studies on the intestinal absorption of radioactive β-carotene and vitamin A in man. Conversion of β-carotene into vitamin A. , 1967 .