Measurement of deuterium-labeled phylloquinone in plasma by LC-APCI-MS

Authors: FU, XUYEAN - JM USDA HNRCA @ TUFTS; Dolnikowski, Gregory; PETERSON, JAMES - JM USDA HNRCA @ TUFTS; Booth, Sarah

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 10/7/2008
Publication Date: 4/18/2009
Citation: Fu, X., Dolnikowski, G., Peterson, J., Booth, S.L. 2009. Measurement of deuterium-labeled phylloquinone in plasma by LC-APCI-MS. Journal of Federation of American Societies for Experimental Biology. Abstract No. 566.1.

Interpretive Summary:

Technical Abstract: Deuterium-labeled vegetables were fed to humans for the measurement of both unlabeled and deuterium-labeled phylloquinone in plasma. We developed a technique to determine the quantities of these compounds using liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization (LC-APCI-MS). Sample preparation involved liquid-liquid and solid-phase extraction techniques. The internal standard (K1(25)) was used to quantify both unlabeled and labeled phylloquinone. The standard calibration curve had a linear correlation coefficient (R2) of 0.998 and 0.999 for unlabeled and labeled phylloquinone, respectively. The minimal detectable concentration of unlabeled and labeled phylloquinone was 0.05 and 0.08 pmol/injection. For pooled plasma samples, spiked with 0.5 to 32 nmol phylloquinone/L, average recoveries were 95 +/- 4.0 % for unlabeled phylloquinone and 96 +/- 7.9 % for labeled phylloquinone. The phylloquinone concentrations determined by LC- fluorescence and LC-APCI-MS methods from healthy subjects (n=20) were correlated (R2=0.983, P=0.053). This new method allows us to measure labeled phylloquinone concentrations in healthy subjects (n=3) in response to ingesting deuterium-labeled food. The LC-APCI-MS method is a sensitive and accurate technique for determination of both labeled and unlabeled phylloquinone, and can be applied to bioavailability studies.