DETERMINATION OF VITAMIN B12 IN CEREAL AND MULTIVITAMIN TABLET REFERENCE MATERIALS USING A NOVEL HPLC-ICP-MS METHOD

 

Siva Kesava Raju Chinthalapati, Lee Yu, John Schiel and Stephen E Long

 

Vitamin B12 is a water-soluble B complex vitamin consisting of a cobalt metal ion attached to a Corrin ring structure. Vitamin B12 plays a vital role in many important physiological functions, acting as a coenzyme for normal DNA synthesis, promoting growth and cell development and maintenance of the myelin sheath surrounding nerve cells. Deficiency of vitamin B12 is linked to a variety of health problems including hematological disorders and neurological disorders.

There is growing interest in knowing the exact amount of vitamin B12 in both foods and biological samples. In the pharmaceutical industry and the food supplementation industry, it would be very useful to have advanced analytical methodology which permits accurate and rapid determination of trace levels of vitamin B12. The most widely used methods for quantification of vitamin B12 are microbiological assays which are time-consuming to perform. High-performance liquid chromatography (HPLC) coupled with inductively coupled plasma-mass spectrometry (ICP-MS) has become a versatile and powerful approach for trace element speciation. We have developed a simple, but highly effective, coupled HPLC-ICP-MS method for the accurate determination of vitamin B12. The method is based on separation of vitamin B12 from free cobalt using an Atlantis LC column with a highly-aqueous mobile phase, followed by ion specific detection of the cobalt with ICP-MS. Data for analytical validation of the method, and the application of the method to the determination of vitamin B12 mass fractions in Standard Reference Materials including SRM 3280 (Multivitamin Tablets) and candidate SRM 3233 (Fortified Breakfast Cereal), will be presented.