Matrix Effects on the Fragmentation of Vitamin B12 in Plasma Desorption Mass Spectrometry

A continuing effort in mass spectrometry is to optimize desorption/ionization processes in order to enhance analyte ion yields and reduce fragmentation. The effect of small carbohydrate and amino acid matrices on the yield of secondary ions from vitamin B₁₂ (cyanocobalamin) was examined using plasma desorption mass spectrometry. The extent of the corrin decomposition is dependent upon the matrix-to-analyte ratio. The enhanced yields of the high-mass fragment ion M–CN + H]⁺ and the ions corresponding to protonated molecules, however, are dependent upon both the matrix-to-analyte ratio and the nature of the matrix. © 1997 John Wiley & Sons, Ltd.