title: The estimation of vitamin D and some metabolites in human plasma by mass fragmentography.
abstract: A mass fragmentographic assay for vitamin D3, 25-hydroxyvitamin D3, 25-hydroxyvitamin D2 and 24,25-dihydroxyvitamin D3 is described. After extraction of plasma with methanol and dichloromethane, Lipidex 5000 chromatography was used to separate the plasma extract into three fractions (a vitamin D fraction, a 25-hydroxyvitamin D fraction and a 24,25-dihydroxyvitamin D fraction). Cholesterol was removed from the vitamin D fractio by thin-layer chromatography. :After addition of vitamin D2 to each fraction, isotachysterol trimethylsilyl ethers were formed. Recoveries prior to gas chromatography-mass spectrometry were assessed by the use of tritiated standards added to the plasma before extraction. Using this procedure, normal ranges were established (vitamin D3: 3--17.7, 25-hydroxyvitamin D3: 5.9--35.2, 25-hydroxyvitamin D2: 0.6---1.0 and 24,25-dihydroxyvitamin D3: 0.6--2.9 micrograms/l).
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol; D002762:Cholecalciferol / Q000097:blood; D004100:Dihydroxycholecalciferols / Q000097:blood; D004872:Ergocalciferols / Q000031:analogs & derivatives / Q000097:blood; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D014807:Vitamin D / Q000097:blood*
chemical_list: D004100:Dihydroxycholecalciferols; D004872:Ergocalciferols; D006887:Hydroxycholecalciferols; D014807:Vitamin D; D002762:Cholecalciferol; D015652:25-Hydroxyvitamin D 2; D015650:24,25-Dihydroxyvitamin D 3; D002112:Calcifediol