title: Determination of 25-hydroxyvitamin D3 in human plasma using a non-radioactive tetranorvitamin D analogue as an internal standard.
abstract: A convenient non-radioactive method for assaying plasma 25-hydroxyvitamin D3 is described. The method uses 22-hydroxytetranorvitamin D3 as an internal standard and includes two-step liquid- and solid-phase extractions and quantification by normal-phase HPLC. The intra- and inter-assay coefficients of variation were 2.2% and 2.4%, respectively, and the analytical recovery of 25-hydroxyvitamin D3 added to plasma was quantitative. Assay linearity was obtained in the range 0.5-4.0 ml of plasma. When compared with the method employing a radioactive 25-hydroxyvitamin D3 tracer, the correlation coefficient was 0.990 (slope 0.999 and intercept 1.19 ng/ml).
authors.affiliation: Division of Molecular Biology, Tokyo Medical and Dental University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: H
authors.initials: H
authors.lastname: Ishida
authors.forename: S
authors.initials: S
authors.lastname: Yamada
mesh_terms: D000328:Adult; D002112:Calcifediol / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014807:Vitamin D / Q000031:analogs & derivatives*
chemical_list: D007202:Indicators and Reagents; D014807:Vitamin D; D002112:Calcifediol