<> <http://www.w3.org/2000/01/rdf-schema#comment> "The repository administrator has not yet configured an RDF license."^^<http://www.w3.org/2001/XMLSchema#string> . <> <http://xmlns.com/foaf/0.1/primaryTopic> <https://discovery.ucl.ac.uk/id/eprint/348> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/ontology/bibo/AcademicArticle> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/ontology/bibo/Article> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/title> "Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/abstract> "We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their agyclone structures, 2-methyl-3-(3-3-carboxymethylpropyl)-1,4-naphthoquinone (5C-side-chain metabolite) and 2-methyl-3-(5-carboxy-3-methyl-2-pentenyl)-1,4-naphthoquinone (7C-side-chain metabolite), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversed-phase (C18) solid phase extraction (SPE) and the predominately conjugated vitamin K metabolites hydrolysed with methanolic HCl. The resultant carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE. Final analysis was by reversed-phase (C18) HPLC with a methanol-aqueous mobile phase. Metabolites were detected by amperometric, oxidative ECD of their quinol forms, which were generated by post-column coulometric reduction at an upstream electrode. The assay gave excellent linearity (r2 typically = 0.999) and high sensitivity with an on-column detection limit of <3.5 fmol (<1pg). The inter-assay precision was typically 10%. Metabolite recovery was compared to that of an internal standard (2-methyl-3-(7'-carboxy-heptyl)-1,4-naphthoquinone), added to urine samples just before analysis. Using this methodology we confirmed that the 5C- and 7C-metabolite were major catabolites of both phylloquinone (vitamin K1) and menaquinones (vitamin K2) in humans. We propose that the measurement of urinary vitamin K metabolite excretion is a candidate non-invasive marker of total vitamin K status."^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/date> "2005-05" . <https://discovery.ucl.ac.uk/id/document/230> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/ontology/bibo/Document> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/volume> "46" . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/issue> "5" . <https://discovery.ucl.ac.uk/id/publication/ext-00222275> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/ontology/bibo/Collection> . <https://discovery.ucl.ac.uk/id/publication/ext-00222275> <http://xmlns.com/foaf/0.1/name> "The Journal of Lipid Research"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/isPartOf> <https://discovery.ucl.ac.uk/id/publication/ext-00222275> . <https://discovery.ucl.ac.uk/id/publication/ext-00222275> <http://www.w3.org/2002/07/owl#sameAs> <urn:issn:00222275> . <https://discovery.ucl.ac.uk/id/publication/ext-00222275> <http://purl.org/ontology/bibo/issn> "00222275" . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/status> <http://purl.org/ontology/bibo/status/peerReviewed> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/authorList> <https://discovery.ucl.ac.uk/id/eprint/348#authors> . <https://discovery.ucl.ac.uk/id/eprint/348#authors> <http://www.w3.org/1999/02/22-rdf-syntax-ns#_1> <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/authorList> <https://discovery.ucl.ac.uk/id/eprint/348#authors> . <https://discovery.ucl.ac.uk/id/eprint/348#authors> <http://www.w3.org/1999/02/22-rdf-syntax-ns#_2> <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/authorList> <https://discovery.ucl.ac.uk/id/eprint/348#authors> . <https://discovery.ucl.ac.uk/id/eprint/348#authors> <http://www.w3.org/1999/02/22-rdf-syntax-ns#_3> <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/authorList> <https://discovery.ucl.ac.uk/id/eprint/348#authors> . <https://discovery.ucl.ac.uk/id/eprint/348#authors> <http://www.w3.org/1999/02/22-rdf-syntax-ns#_4> <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> <https://discovery.ucl.ac.uk/id/person/ext-26bc8ccba3755cad6d0a995e0d4c2416> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/ontology/bibo/authorList> <https://discovery.ucl.ac.uk/id/eprint/348#authors> . <https://discovery.ucl.ac.uk/id/eprint/348#authors> <http://www.w3.org/1999/02/22-rdf-syntax-ns#_5> <https://discovery.ucl.ac.uk/id/person/ext-26bc8ccba3755cad6d0a995e0d4c2416> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/creator> 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<http://xmlns.com/foaf/0.1/name> "SJ Hodges"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> . <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> <http://xmlns.com/foaf/0.1/givenName> "DJ"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> <http://xmlns.com/foaf/0.1/familyName> "Harrington"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-07a417ea5cdfe79f1e4a14c13aed1f1f> <http://xmlns.com/foaf/0.1/name> "DJ Harrington"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> . <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> <http://xmlns.com/foaf/0.1/givenName> "GF"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> <http://xmlns.com/foaf/0.1/familyName> "Savidge"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-7bb1a4f04b79a25b3b1db30583498860> <http://xmlns.com/foaf/0.1/name> "GF Savidge"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-f5bd399bb95e0a0a135f4da220e0d065> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> . <https://discovery.ucl.ac.uk/id/person/ext-f5bd399bb95e0a0a135f4da220e0d065> <http://xmlns.com/foaf/0.1/givenName> "MJ"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-f5bd399bb95e0a0a135f4da220e0d065> <http://xmlns.com/foaf/0.1/familyName> "Shearer"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-f5bd399bb95e0a0a135f4da220e0d065> <http://xmlns.com/foaf/0.1/name> "MJ Shearer"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> . <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> <http://xmlns.com/foaf/0.1/givenName> "C"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> <http://xmlns.com/foaf/0.1/familyName> "Edwards"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-9e607e7aaecda58d5237914a2486a0f2> <http://xmlns.com/foaf/0.1/name> "C Edwards"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> . <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> <http://xmlns.com/foaf/0.1/givenName> "R"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> <http://xmlns.com/foaf/0.1/familyName> "Soper"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/person/ext-50b5ede33c4d42238c7e52a0bfe3f144> <http://xmlns.com/foaf/0.1/name> "R Soper"^^<http://www.w3.org/2001/XMLSchema#string> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://eprints.org/ontology/EPrint> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://eprints.org/ontology/ArticleEPrint> . <https://discovery.ucl.ac.uk/id/eprint/348> <http://purl.org/dc/terms/isPartOf> <https://discovery.ucl.ac.uk/id/repository> . 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