FRAGMENTATION OF VITAMIN-B-12 DURING 337 NM MATRIX-ASSISTED LASER-DESORPTION IONIZATION

被引:42
作者
KINSEL, GR [1 ]
PRESTON, LM [1 ]
RUSSELL, DH [1 ]
机构
[1] TEXAS A&M UNIV,DEPT CHEM,COLLEGE STN,TX 77843
关键词
D O I
10.1002/bms.1200230404
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
Matrix-assisted laser desorption ionization of vitamin B-12 at 337 nm yields low abundances of the protonated molecule in time-of-flight mass spectra when the matrix alpha-cyano-4-hydroxycinnamic acid is used. A variety of fragment ions are observed in the time-of-flight mass spectra which may be assigned on the basis of previous studies of vitamin B-12 fragmentation. When the matrix 4-hydroxy-3-iodo-5-nitrobenzoic acid is used, an abundant signal from the protonated molecule ion of vitamin B-12 is produced. Fragment ions are still observed in the time-of-flight mass spectra but at much lower abundances. Studies of the influence of matrix-to-analyte ratio and desorbing laser intensity argue against direct photodissociation as the mechanism of fragment ion formation. Matrix choice appears to most strongly influence the internal energies of the laser-desorbed ions thereby controlling the fragmentation processes.
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页码:205 / 211
页数:7
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