A novel specific assay of 25-hydroxy vitamin D.
Clinica chimica acta; international journal of clinical chemistry
confidence
Key findings
Describes a novel mass fragmentographic assay for 25-hydroxy vitamin D3 with relative standard deviation ~5%; analytical methods paper.
View source on PubMed (PMID 1277536) ↗
- Sample size
- Not reported
- Population
- Human serum samples (analytical method development)
- Dosing
- 250 ng internal standard added to 2.5 ml serum
- Duration
- Not applicable
- Route
- In vitro (assay)
- Blinding
- not_reported
- Controls
- none
- Drug class
- fat-soluble vitamin
Full abstract
The synthesis of 25-hydroxy-[26-2H3]vitamin D3 is described. A fixed amount of this compound (usually 250 ng) is added to a fixed amount of serum (usually 2.5 ml) and the mixture is extracted with a chloroform/methanol mixture. The extract is chromatographed on a Sephadex LH-20 column together with a trace amount of 25-hydroxy-[263H3]vitamin D3. The chromatographic fraction corresponding to 25-hydroxy vitamin D3 is converted into trimethylsilyl ether and the amount of unlabeled 25hydroxy vitamin D3 is determined from the ratio between the mass fragmentographic recording at m/e 131 (base peak of unlabeled 25-hydroxy vitamin D3) and m/e 134 (base peak 25-hydroxy-[26-2H3]vitamin D3). The relative standard deviation of the method was about 5%.