title: Determination of serum vitamins 25-OH-D2 and 25-OH-D3 with liquid chromatography-tandem mass spectrometry using atmospheric pressure chemical ionization or electrospray source and core-shell or sub-2 μm particle columns: a comparative study.
abstract: OBJECTIVE
  Develop a simple LC-MS-MS method for determination of 25-hydroxymetabolites of vitamin D2 and D3 in serum.
  
  
  METHODS
  0.1 mL serum was mixed with 0.3 mL deproteinizing mixture containing two deuterated internal standards. Two LC-MS-MS systems were used: Waters Premier with an ESI source and a Hypersil Gold RP 18 50 × 2.1 mm column, and a Thermo Quantum, with an APCI source and a Kinetex RP 18 core-shell 50 × 2.1 mm column. Certified reference material 972 from NIST was used for method calibration. The samples were additionally analyzed with commercial HPLC procedure.
  
  
  RESULTS
  Baseline separation of compounds was achieved in 6 min run time. Both systems have limits of detection of 0.5 nmol/L and recovery ranging from 86% to 112%. The measurement of 25-OH-D3 gave comparable results for all procedures; the results of 25-OH-D2 measurement obtained with the HPLC often differed from those obtained with LC-MS-MS methods.
  
  
  CONCLUSIONS
  Established procedure performed well for ESI and APCI sources and totally porous and core-shell LC columns. The use of two internal standards enhanced the accuracy of the measurements.
authors: Royal Clinics, Riyadh, Saudi Arabia. mbogusz@web.de
authors: Maciej J
authors: MJ
authors: Bogusz
authors: Eid
authors: E
authors: Al Enazi
authors: Monther
authors: M
authors: Tahtamoni
authors: Jamil Abdel
authors: JA
authors: Jawaad
authors: Mohammed
authors: M
authors: Al Tufail
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001274:Atmospheric Pressure; D002112:Calcifediol / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
chemical_list: D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol