PMID- 8124861 OWN - NLM STAT- MEDLINE DCOM- 19940414 LR - 20190904 IS - 0009-9120 (Print) IS - 0009-9120 (Linking) VI - 26 IP - 6 DP - 1993 Dec TI - Gas chromatographic-mass fragmentographic determination of serum 1 alpha,25 dihydroxyvitamin D3. PG - 461-9 AB - We extracted 1 alpha,25-dihydroxyvitamin D3[1 alpha,25(OH)2D3] from 10 mL serum using Sep-Pak C18 and Sep-Pak Silica mini-columns and normal-phase high performance liquid chromatography (HPLC) separation for analysis by gas chromatography-mass fragmentography (GC-MS). A GC-MS method was optimised using manual tuning for ion mass calibration and selective ion monitoring (SIM) for quantitation. Serum 1 alpha,25(OH)2D3 was identified by superimposition of the m/z 452 and 501 ion peaks and by overlapping the m/z 452 ion peak with that of its authentic standard. It was quantitated from the relative peak areas of its m/z 452 ion and the m/z 363 ion of vitamin D2, the internal standard. Twenty picograms of 1 alpha,25(OH)2D3 gave a peak with a signal-to-noise ratio of 26:1. Between-batch coefficient of variation (CV) for 1 alpha,25(OH)2D3 standard was < 13%. However, serum analysis was less precise, within-batch CV being 20%. The analytical recovery was about 70% and detection limit 0.5 pg/mL. When compared with a commercial radioreceptor assay we still found our method to be sensitive, specific, and adequate for confirmative and semiquantitative analysis of serum 1 alpha,25(OH)2D3. FAU - Poon, P M AU - Poon PM AD - Department of Chemical Pathology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT. FAU - Mak, Y T AU - Mak YT FAU - Pang, C P AU - Pang CP LA - eng PT - Journal Article PL - United States TA - Clin Biochem JT - Clinical biochemistry JID - 0133660 RN - FXC9231JVH (Calcitriol) SB - IM MH - Calcitriol/*blood MH - Chromatography, Gas/*methods MH - Chromatography, High Pressure Liquid MH - Humans MH - Sensitivity and Specificity EDAT- 1993/12/01 00:00 MHDA- 1993/12/01 00:01 CRDT- 1993/12/01 00:00 PHST- 1993/12/01 00:00 [pubmed] PHST- 1993/12/01 00:01 [medline] PHST- 1993/12/01 00:00 [entrez] AID - 0009-9120(93)80010-R [pii] AID - 10.1016/0009-9120(93)80010-r [doi] PST - ppublish SO - Clin Biochem. 1993 Dec;26(6):461-9. doi: 10.1016/0009-9120(93)80010-r.