Characterization of vitamin D3 metabolites using continuous-flow fast atom bombardment tandem mass spectrometry and high-performance liquid chromatography.
A mass spectrometric method for the detection of vitamin D3 metabolites is described. This method involves the derivatization of the metabolites by cycloaddition with 4-phenyl-1,2,4-triazoline-3,5-dione, followed by their characterization by continuous-flow fast atom bombardment (CF-FAB) tandem mass spectrometry (MS-MS) and high-performance liquid chromatography (HPLC). Using HPLC, this derivatization has been shown to increase the UV detectability of 25-hydroxyvitamin D3 by about 5-fold. The FAB spectra of the adducts are dominated by peaks corresponding to a protonated molecule and a fragment ion derived in part from the loss of the side chain. Multiple reaction monitoring (MRM) of this transition by MS-MS may be utilized for trace level analysis of vitamin D metabolites. Sample introduction by flow injection yields detection limits in the low nanogram to high picogram range, whereas the use of on-line capillary LC has been found to decrease the detection limits to the low picogram level.
Yeung
B
B
Department of Chemistry, Northeastern University, Boston, MA 02115.
Vouros
P
P
Reddy
G S
GS
D002762:Cholecalciferol / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013056:Spectrophotometry, Ultraviolet; D014230:Triazoles
D014230:Triazoles; C068159:4-methyl-1,2,4-triazoline-3,5-dione; D002762:Cholecalciferol; C053540:4-phenyl-1,2,4-triazoline-3,5-dione