Title: Determination of Selected B-complex Vitamins in the NIST Multivitamin Reference Standard Material by Stable Isotope Dilution Mass Spectrometry (Experimental Biology, April, 2007, Washington, D.C.) Authors
Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 2006
Publication Date: April 1, 2007
Citation: Chen, P., Ozcan, M., Wolf, W.R. 2007. Determination of Selected B-complex Vitamins in the NIST Multivitamin Reference Standard Material by Stable Isotope Dilution Mass Spectrometry. Experimental Biology, April 25, 2007, Washington, D.C. Technical Abstract: There is increased interest in accurately assessing the total dietary intake of vitamins from all sources, including foods and dietary supplements. Isotope dilution can be a definitive analytical method for very accurate concentration determinations. Thus, a liquid chromatographic (LC) isotope dilution mass spectrometric (IDMS) method for determination of multiple water soluble vitamins in dietary supplement tablets has been investigated. As part of a collaborative characterization of the NIST SRM 3280: Multivitamin/Multimineral Tablets, isotopically labeled (13C and/or 2H) B-vitamins (B1-thiamine, B6-pyridoxine, nicotinamide, pantothenic acid, folic acid and biotin) were obtained from commercial sources, with support of the Office of Dietary Supplements (NIH). Our LC-IDMS method (developed in part to help assign values to SRM 3280) uses a C18 reverse phase column, an Agilent 1100 HPLC system, and a Quattro Micro triple-quad mass spectrometer (MS). B-vitamin determination was achieved using a gradient LC profile combined with MS/MS detection in MRM (multiple reaction monitoring) mode. Stock solutions of the isotopically labeled vitamins were calibrated against USP standard solutions. The SRM tablets, with added amounts of the six isotopically labeled B-vitamins, were extracted and analyzed in a single LC run. Unknown vitamin concentrations were calculated by comparing the ratio of the integrated LC peak at the different masses of the unlabeled and labeled vitamins.