title: Quantitative determination of plasma vitamin K1 by high-performance liquid chromatography coupled to isotope dilution tandem mass spectrometry.
abstract: Plasma vitamin K1 (phylloquinone) determination is commonly used for the diagnosis of vitamin K deficiency in patients suffering from lipid malabsorption. Moreover, current evidence that adequate vitamin K intake, and correspondingly adequate plasma vitamin K1 concentration, could also be of importance in relation to bone and brain diseases emphasizes the need to improve the current analytical methods. We developed a liquid chromatography coupled to tandem mass spectrometry method using a stable isotope ring-D4-labeled internal standard of vitamin K1 and operating in the multiple reaction monitoring mode by the selection of a precursor and product ions. The atmospheric pressure chemical ionization (APCI) method was shown to be more sensitive than electrospray ionization. After a single-step extraction with cyclohexane, chromatographic separation was performed on a C18 column with an isocratic mobile phase. The linearity was up to 5400ng/L, and the limit of detection was 14ng/L. Intra- and interrun precision were 2.4% and 8.3%, respectively, for the lower limit of the reference range. Recovery was better than 98%. The method is simple and reliable, allowing accurate vitamin K1 measurement in plasma samples from healthy subjects and patients suffering from vitamin K deficiency.
authors.affiliation: Département de Biologie Intégrée, Centre Hospitalier Universitaire, 38043 Grenoble, France. vducros@chu-grenoble.fr
authors.forename: Véronique
authors.initials: V
authors.lastname: Ducros
authors.forename: Mickaël
authors.initials: M
authors.lastname: Pollicand
authors.forename: François
authors.initials: F
authors.lastname: Laporte
authors.forename: Alain
authors.initials: A
authors.lastname: Favier
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003510:Cyclohexanes / Q000737:chemistry; D006801:Humans; D007553:Isotope Labeling; D053719:Tandem Mass Spectrometry / Q000379:methods*; D010837:Vitamin K 1 / Q000097:blood* / Q000302:isolation & purification; D014813:Vitamin K Deficiency / Q000175:diagnosis
chemical_list: D003510:Cyclohexanes; C506365:Cyclohexane; D010837:Vitamin K 1