Mass spectrometry cobalamins

Stabler SP, Marcell PD, Podell ER, Allen RH, Savage DG, Lindenbaum J (1988) Elevation of total homocysteine in the serum of patients with cobalamin or folate deficiency detected by capillary gas chromatography-mass spectrometry. J Clin Invest 81 466-474... 

Among the other soft ionization techniques is laser microprobe mass spectrometry (LAMMA) in which a laser pulse is used to vaporize a small amount of sample, as discussed in a 1982 review (108). Of interest to us is the application to the study of some cobalamins (109). (M + H) and (M - H) ions were observed in the positive and negative ion modes, respectively. However, there were few other high-mass fragments that could be used to impart structural information. 

Baker, S.A., Miller-Ihli, N.J. Determination of cobalamins using capillary electrophoresis inductively coupled plasma mass spectrometry. Spectrochim. Acta B 55, 1823-1832 (2000)... 

Coverage includes B vitamins and folate in the context of a historical background, disease, cardiovascular effects and the importance of vitamins in biochemistry as illustrated by a single vitamin. Thereafter there are chapters on the chemistry and biochemistry of thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate and cobalamin. Methodical aspects include characterization and assays of B vitamins and folate in foods of all kinds, dietary supplements, biological fluids and tissues. The techniques cover solid-phase extraction, spectrofluorimetry, mass spectrometry, HPLC, enzymatic assay, biosensor and chemiluminescence. In terms of fimction and effects or... 

Chen, J.H., and Jiang, S.J. 2008. Determination of cobalamin in nutritive supplements and chlorella foods by capillary electrophoresis-inductively coupled plasma mass spectrometry. Journal of Agricultural and Food Chemistry. 56(4) 1210-1215. 

Mass Spectrometry. Different varieties of mass spectrometry have for several years been used to identify the chemical nature of cobalamins produced from microorganisms (Kumudha et al. 2010). The sensitivity of mass spectrometry is still insufficient for measurement of cobalamins in the picomolar range and this method is therefore of limited interest for analysis of human serum. If the sensitivity is improved, mass spectrometry is predicted to be a very strong tool for identification of the varieties of cobalamins and cobalamin analogues present in human serum. 

In the years to come it is to be expected that definitive methods for measurement of cobalamin will be developed, most likely employing mass spectrometry. It is also expected that measurement of holoTC may partly replace measurement of cobalamin as a means to determine cobalamin deficiency. At the same time there will remain a need for new methods in order to understand the flow of cobalamin from food items to the end station inside the cells of the body. 

The latest developments in mass spectrometry with respect to soft ionization of nonvolatile and thermolabile compounds have brought this technique to the level where it may open, and indeed has opened, new ways in cobalamin research, especially when integrated with HPLC. 

The analysis of intact cobalamines by mass spectrometry requires desorption ionization methods and the first spectrum of vitamin B12 (20) containing molecular ion species was obtained in 1978 using FDMS 86), By a careful analysis of the relative abundances of the and C-containing... 

Barber, M., R. S. Bordoli, D. Sedgwick, and A. N. Tyler Fast Atom Bombardment Mass Spectrometry of Cobalamines. Biomed. Mass Spectrom. 8, 492 (1981). 

---