Measurement of 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D2 and 25,26-dihydroxyvitamin D2 in a single plasma sample by mass fragmentography.
A specific and sensitive assay for the measurement of the concentration of 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D2 and 25,26-dihydroxyvitamin D2 in a single plasma sample is described, using stable isotope dilution mass fragmentography. After addition of appropriate deuterium-labelled internal standards, plasma samples were treated with acetonitrile to precipitate protein, and vitamin D metabolites were extracted on prepacked microparticulate reverse-phase cartridges. Further purification was achieved using straight-phase cartridges and high-performance liquid chromatography. Gas chromatography-mass spectrometry was carried out after appropriate derivatisation of samples and standards. The method has been evaluated in terms of specificity, recovery of added standards, and reproducibility.
Coldwell
R D
RD
Department of Chemical Pathology, London Hospital Medical College, UK.
Trafford
D J
DJ
Varley
M J
MJ
Kirk
D N
DN
Makin
H L
HL
D002112:Calcifediol / Q000097:blood; D002762:Cholecalciferol / Q000097:blood; D004872:Ergocalciferols / Q000097:blood; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood* / Q000302:isolation & purification
D004872:Ergocalciferols; D006887:Hydroxycholecalciferols; D002762:Cholecalciferol; D002112:Calcifediol