Rapid and simple HPLC analysis of vitamin K in food, tissues and blood

The lack of precise data in food composition tables and also in human and animal plasma concentrations of phylloquinone and other vitamers demands intensive investigation of both; appropriate analytical methods are necessary. Sensitive and selective detection, simplicity and rapidity of the method, and precision and reliability of the data are recommended. Based on a RP-HPLC assay using post-column derivatization and fluorescence detection, combined with a liquid–liquid sample clean-up, a simple and rapid assay is presented. The application to food, human plasma and animal tissues is shown. The samples cover a wide range of matrices, from those of fairly low, e.g. human plasma and milk, to those of high phylloquinone content, e.g. broccoli. For verification purposes mass-spectroscopy (for human plasma) or different fluorescence wavelengths (for the food items) were applicated. Coefficients of variation did not exceed 10% for any matrix and there were no remarkable losses over the whole analytical process. The lower limit of detection for plasma samples was estimated as 0.04 ng/ml.