METHOD DEVELOPMENT FOR THE DETERMINATION OF VITAMIN B12 IN SRM 3280 MULTIVITAMIN/MULTIELEMENT TABLETS

Candice G. Jongsma, Danielle Cleveland, Karen W. Phinney

Analytical Chemistry Division, CSTL, NIST

Vitamins play an essential role in a variety of physiological and cellular functions.  While these nutrients are predominantly obtained through food consumption, multivitamin tablets containing a variety of vitamins and minerals are also frequently used to supplement the diet. Vitamin B12 (cyanocobalamin) is of particular interest due to its physiological effects in the body. Vitamin B12 is essential for DNA synthesis, helps maintain healthy nerve and red blood cells, and is involved in the metabolism of certain amino acids. Deficiency in B12 affects the body in many ways, ranging from the more mild symptoms of nausea and fatigue, to more severe symptoms of dementia and vision problems, and even the potentially life threatening disease of pernicious anemia.

The Standard Reference Material (SRM) 3280, a multivitamin tablet, was developed for use in validating analytical methods for the determination of vitamins, carotenoids, and elements in dietary supplement tablets. Vitamin B12 is present in very low quantities compared to the other vitamins and minerals found in a multivitamin. This makes B12 difficult to measure because the concentration falls below the detectable limit of many common analytical techniques, such as UV detection, and no structurally similar internal standard is available for quantification by mass spectrometry (MS).

 Methods for the determination of B12 in a multi-vitamin tablet are under development. A chromatographic method for the separation of B12 from the other multivitamin constituents has been developed using reversed phase liquid chromatography (LC).  Suitable methods of detection are currently being assessed. One promising possibility is to couple the LC with an inductively coupled plasma (ICP) -MS and measure the cobalt signal exhibited from B12.  Another possibility is electrochemical detection. Preliminary results using both of these detection methods will be presented.