Determination of cobalamin in nutritive supplements and chlorella foods by capillary electrophoresis-inductively coupled plasma mass spectrometry

J Agric Food Chem. 2008 Feb 27;56(4):1210-5. doi: 10.1021/jf073213h. Epub 2008 Feb 2.

Abstract

A capillary electrophoresis-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for the determination of cobalamin is described. Samples of cobalt-containing compounds were subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI-100) of ICP-MS. The Co-containing compounds studied include cyanocobalamin (CN-Cbl, vitamin B12), hydroxocobalamin (OH-Cbl), and Co(II). The species studied were well separated using a 70 cm lengthx75 microm i.d. fused silica capillary with the applied voltage set at +20 kV. A 25 mM Tris buffer (pH 9.0) containing 15 mM sodium dodecyl sulfate (SDS) was used as the electrophoretic buffer. The CE-ICP-MS detection limits were 0.3, 0.2, and 1.7 ng of Co mL(-1) for CN-Cbl, OH-Cbl, and Co(II), respectively. The concentrations of cobalamin compounds were determined in selected nutritive supplements and chlorella samples. A microwave-assisted extraction method was used for the extraction of these compounds. Over 92% of the total cobalt species was extracted using a 5% v/v HNO3 solution in a focused microwave field within a period of 10 min; spike recovery was in the range of 94-105% for various species. The major cobalt species in nutritive supplements and chlorella samples was cyanocobalamin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorella / chemistry*
  • Dietary Supplements / analysis*
  • Electrophoresis, Capillary / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Sodium Dodecyl Sulfate
  • Tandem Mass Spectrometry / methods*
  • Vitamin B 12 / analysis*

Substances

  • Sodium Dodecyl Sulfate
  • Vitamin B 12