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A simple and sensitive HPLC-ICP-MS method for the accurate determination of Vitamin B12 in Fortified Breakfast Cereals and Multivitamin Tablet Reference Materials

Published

Author(s)

Siva K. Chinthalapati, Lee L. Yu, John E. Schiel, Stephen E. Long

Abstract

A sensitive high performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of vitamin B12. The method was based on efficient isocratic separation with a mobile phase consisted of 20 mM ethylenediaminetetraacetic acid (EDTA) in 25/75 methanol/water mixture operating at a flow rate of 0.2 mL/min. After HPLC separation, ionic cobalt, cyanocobalamin, methylcobalamin, and cyanocobalamin were measured as 59Co by ICP-MS. For Co as cyanocobalamin, the method has shown good repeatability relative standard deviation (RSD) of around 3 % for ten measurements and excellent linearity between 0.1 ng/g and 100 ng/g (linear regression, R2 > 0.99). The limit of detection (LOD) value for cyanocobalamin was found to be less than 1 ng/g, which permits the method to be employed for the determination of ultra-trace concentrations of vitamin B12 in various types of dietary supplements. Cyanocobalamin in aqueous solution was found to decompose under the ambient light of the laboratory; therefore, dark room conditions are required for the determination of vitamin B12 in the form of cyanocobalamin to minimize the photon-induced decomposition. In an effort to determine total cobalt in a commercial high purity cyanocobalamin using direct ICP-MS measurement as part of an effort to characterize the chemical for use as a calibrant, it was observed that quantitative measurement of cyanocobalamin was achieved only through a complete acid digestion. The method was applied to the determination of vitamin B12 in candidate Standard Reference Material (SRM) 3233 Fortified Breakfast Cereal. SRM 3280 Multivitamin/Multielement Tablet was used for quality assurance of the cereal sample measurements. The amount of vitamin B12 found at 0.187 ± 0.016 mg/kg and 4.38 ± 0.05 mg/kg were in good agreement with the certified values of 0.210 ± 0.040 mg/kg and 4.8± 1.0 mg/kg for SRM 3233 and 3280, respectively.
Citation
Journal of Analytical Atomic Spectrometry
Volume
28

Keywords

Vitamin B12, cyanocobalamin, HPLC, ICP-MS, Standard reference material, dietary supplement.

Citation

Chinthalapati, S. , Yu, L. , Schiel, J. and Long, S. (2013), A simple and sensitive HPLC-ICP-MS method for the accurate determination of Vitamin B12 in Fortified Breakfast Cereals and Multivitamin Tablet Reference Materials, Journal of Analytical Atomic Spectrometry, [online], https://doi.org/10.1039/c3ja30383g (Accessed July 18, 2024)

Issues

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Created April 10, 2013, Updated November 10, 2018