Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9753347 | Journal of Chromatography B | 2005 | 8 Pages |
Abstract
A HPLC fluorescence determination method for Vitamin K derivatives (Vitamin K1, phylloquinone, PK and K2, menaquinones, MK-4 and MK-7) using post-column reduction and internal standards was developed. Selectivity and reproducibility were increased by optimized chromatography conditions and satisfactory precision and accuracy were attained by using synthetic internal standards. After addition of internal standards to plasma samples, lipids were extracted with ethanol and hexane. Chromatography was performed by isocratic reverse phase separation on a C18 column. Vitamin K derivatives were detected at 430Â nm with excitation at 320Â nm for MK-4 and 240Â nm for PK and MK-7. The detection limits for MK-4, PK and MK-7 were 4, 2 and 4Â pg, respectively. The recoveries of MK-4, PK and MK-7 were greater than 92% and the inter- and intra-assay R.S.D. values were 5.7-9.2% for MK-4, 4.9-9.6% for PK and 6.3-19.3% for MK-7. The data showed good correlation between proposed method and LC-APCI/MS method for MK-4 (R2Â =Â 0.988), PK (R2Â =Â 0.979) and MK-7 (R2Â =Â 0.986). The method allows the determination of Vitamin K for evaluating their clinical and nutritional status.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Maya Kamao, Yoshitomo Suhara, Naoko Tsugawa, Toshio Okano,