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Analysis of isotope ratios in vitamin K 1 (phylloquinone) from human plasma by gas chromatography/mass spectrometry
Author(s) -
Jones Kerry S.,
Bluck Leslie J. C.,
Coward W. Andy
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2538
Subject(s) - chemistry , chromatography , mass spectrometry , extraction (chemistry) , vitamin , gas chromatography , high performance liquid chromatography , gas chromatography–mass spectrometry , biochemistry
Abstract Vitamin K 1 is a fat‐soluble vitamin required for the γ ‐carboxylation of vitamin K‐dependent proteins. Recent work has suggested an important role for vitamin K 1 in bone health beyond its more established function in the control and regulation of blood coagulation. However, current UK recommended intakes do not reflect this recent evidence. The use of stable isotopes provides a powerful tool to investigate vitamin K kinetics, turnover and absorption in man, although published methods have reported difficulties in the extraction and analysis of isotope ratios of vitamin K in human plasma. In this paper, we report a new methodology for the extraction and measurement of isotope ratios in vitamin K 1 . Sample clean‐up is achieved with liquid‐liquid extraction, enzyme hydrolysis with lipase and cholesterol esterase, and solid‐phase extraction. Isotopic analysis of the pentafluoropropionyl derivative of vitamin K 1 is performed by gas chromatography/mass spectrometry (GC/MS). The limit of quantitation is equivalent to at least 0.3 nmol/L and the method is demonstrated to be linear over a range of enrichments. This method provides a robust alternative to previous work requiring the use of semi‐preparative high‐performance liquid chromatography (HPLC). Copyright © 2006 John Wiley & Sons, Ltd.