title: Advantages of paper chromatography as a preparative step in the assay of 1,25-dihydroxyvitamin D.
abstract: Ether extraction and paper chromatography were used to separate the main metabolites of vitamin D in plasma [25-(OH), 24,25-(OH)2 and 1,25-(OH)2 vitamin D]prior to radio receptor-assay. The overall procedural loss of the 1,25-(OH)2 vitamin D was 58 +/- 5% (n = 40), corrected for by tracer addition. The sensitivity of the assay was 0.5 fmol/tube, corresponding to 4 pmol/l, and the intra- and inter-assay coefficients of variation were 10.5% and 11.5%, respectively. The range of values measured in healthy controls was 80-200 pmol/l (n = 60), which is in agreement with findings reported in the literature. A comparison of the results of the present procedure with those obtained with a procedure employing C18 purification, disclosed a correlation coefficient of 0.92 (p < or = 0.0001), a slope of 0.89 (p < or = 0.0001) and a small non-significant intercept of 5.0 pmol/l (n = 53).
authors.affiliation: Department of Experimental and Chemical Endocrinology, University Hospital Nijmegen, Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: van Hoof
authors.forename: L M
authors.initials: LM
authors.lastname: Swinkels
authors.forename: J J
authors.initials: JJ
authors.lastname: van Stevenhagen
authors.forename: H
authors.initials: H
authors.lastname: van den Berg
authors.forename: H A
authors.initials: HA
authors.lastname: Ross
authors.forename: T J
authors.initials: TJ
authors.lastname: Benraad
mesh_terms: D000818:Animals; D002417:Cattle; D002854:Chromatography, Paper / Q000379:methods*; D004872:Ergocalciferols / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D011869:Radioligand Assay; D012680:Sensitivity and Specificity
chemical_list: D004872:Ergocalciferols; C003564:1,25-dihydroxyergocalciferol