On-line liquid chromatography and circular dichroism detection of stereo-isomers of α-tocopherol derivatives generated by an electrochemical reaction

Kayoko Tahara, Emi Makii, Shiro Iijima, Yoshihiro Abe, Masataka Mochizuki

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The electrochemical oxidation of (±)-α-tocopherol on a porous graphite electrode was performed in the presence of methanol, and successive separation and detection of the products were performed by an on-line liquid chromatography/ mass spectrometry system. Three products were identified, one of which was determined to be α-tocopheryl quinone, because its m/z was 469 [M+Na]+. The other two products showed identical mass and UV spectra, and were suspected to be diastereomers of 9-methoxy-α-tocopheron, because their molecular weights were m/z 483 [M+Na]+, and also because it is known that the chemical oxidation of α-tocopherol by benzoyl peroxide or N-bromosuccinimide in the presence of methanol should provide 9-methoxy-α-tocopheron. To confirm that these two compounds were diastereomers, a circular dichroism detector was used. The signs of both peaks detected by the circular dichroism detector at 230 nm were opposite. In addition to observations of identical mass and ultraviolet spectra, these results indicated that the two products were diastereomers of 9-methoxy-α- tocopheron, whose stereochemistry is different at the newly generated chiral center of the 9-position. The on-line use of a circular dichroism detector with an electrochemical cell/liquid chromatography system may expand the utility of the system to study the metabolism of a chiral drug. 2008

Original languageEnglish
Pages (from-to)935-938
Number of pages4
JournalAnalytical Sciences
Volume24
Issue number7
DOIs
Publication statusPublished - 2008 Jul

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Tocopherols
Liquid chromatography
Dichroism
Isomers
Derivatives
Detectors
Methanol
Bromosuccinimide
Benzoyl Peroxide
Graphite electrodes
Stereochemistry
Electrochemical cells
Electrochemical oxidation
Metabolism
Mass spectrometry
Molecular weight
Oxidation
Pharmaceutical Preparations

ASJC Scopus subject areas

  • Analytical Chemistry

Cite this

On-line liquid chromatography and circular dichroism detection of stereo-isomers of α-tocopherol derivatives generated by an electrochemical reaction. / Tahara, Kayoko; Makii, Emi; Iijima, Shiro; Abe, Yoshihiro; Mochizuki, Masataka.

In: Analytical Sciences, Vol. 24, No. 7, 07.2008, p. 935-938.

Research output: Contribution to journalArticle

Tahara, Kayoko ; Makii, Emi ; Iijima, Shiro ; Abe, Yoshihiro ; Mochizuki, Masataka. / On-line liquid chromatography and circular dichroism detection of stereo-isomers of α-tocopherol derivatives generated by an electrochemical reaction. In: Analytical Sciences. 2008 ; Vol. 24, No. 7. pp. 935-938.
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