eprintid: 348
rev_number: 128
eprint_status: archive
userid: 1
dir: disk0/00/00/03/48
datestamp: 2005-05-09 12:00:00
lastmod: 2020-06-16 04:30:42
status_changed: 2008-01-09 13:16:38
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Harrington, DJ
creators_name: Soper, R
creators_name: Edwards, C
creators_name: Savidge, GF
creators_name: Hodges, SJ
creators_name: Shearer, MJ
title: Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection
subjects: 5000
divisions: UCL
note: Imported via OAI, 9:29:00 10th May 2005
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.
date: 2005-05
date_type: published
oa_status: green
primo: open
primo_central: open_green
article_type_text: Article
doi: 10.1194/jlr.D400033-JLR200
lyricists_name: HODGES, STEPHEN
lyricists_id: SHODG45
full_text_status: public
publication: The Journal of Lipid Research
volume: 46
number: 5
pagerange: 1053-1060
refereed: TRUE
issn: 0022-2275
citation:        Harrington, DJ;    Soper, R;    Edwards, C;    Savidge, GF;    Hodges, SJ;    Shearer, MJ;      (2005)    Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection.                   The Journal of Lipid Research , 46  (5)   pp. 1053-1060.    10.1194/jlr.D400033-JLR200 <https://doi.org/10.1194/jlr.D400033-JLR200>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/348/1/Vit_K_metabs_JLR_2005.pdf