title: Determination of phylloquinone and menaquinones in animal products with fluorescence detection after postcolumn reduction with metallic zinc.
abstract: A high-performance liquid chromatographic (HPLC) method for the determination of phylloquinone and menaquinones in foods of animal origin is described. The K vitamers were quantified with a fluorescence detector after postcolumn reduction with metallic zinc using K1(25) as an internal standard. Extraction was done either with 2-propanol-hexane (meat and fish products) or with acid hydrolysis method (dairy products). Prior to quantification, sample extracts were purified by semipreparative HPLC; in addition, the fats of cheese and rainbow trout samples were removed with lipase hydrolysis. By this method the phylloquinone and menaquinones (MK-4 to MK-10) present in a few representative samples of different animal food groups were determined. HPLC-MS was used to confirm the identification of K vitamers. Long-chain menaquinones were found from bovine and pig livers as well as from various cheeses. The total vitamin K contents calculated as the sum of quantified K vitamers were in general low (mean content 10-100 ng/g); the highest amount was analyzed in chicken meat (600 ng/g).
authors: Department of Applied Chemistry and Microbiology, University of Helsinki, P.O. Box 27, FIN-00014 University of Helsinki, Finland. Terhi.Koivu@Helsinki.fi
authors: T J
authors: TJ
authors: Koivu-Tikkanen
authors: V
authors: V
authors: Ollilainen
authors: V I
authors: VI
authors: Piironen
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005396:Fish Products / Q000032:analysis*; D005453:Fluorescence; D008461:Meat Products / Q000032:analysis*; D014812:Vitamin K / Q000302:isolation & purification*; D010837:Vitamin K 1 / Q000302:isolation & purification*
chemical_list: D014812:Vitamin K; D010837:Vitamin K 1