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Mass spectroscopic studies of riboflavin and isotopically labelled lumiflavins
Author(s) -
Holzmann Gerhard,
Bock Michael,
Elsner Martin,
Kurreck Harry,
Müler Franz
Publication year - 1988
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210231110
Subject(s) - fragmentation (computing) , chemistry , riboflavin , electron ionization , metastability , ion , ionization , mass spectrometry , medicinal chemistry , methyl group , stereochemistry , chromatography , organic chemistry , group (periodic table) , biochemistry , computer science , operating system
Under electron impact conditions 3‐methylriboflavin is attacked at the ribityl side chain to generate 3‐methyl‐lumiflavin. This is verified by analysis of metastable fragmentations and comparison with model ions. Formation of 1,3‐dimethyl‐lumkhrome through migration of the methyl group from N(10) to position N(1) is positively excluded. A general fragmentation scheme for ionized 3‐methyl‐lumiflavin is developed based on exact mass measurements using various 2 H, 13 C and 15 N isotopically labelled derivatives. The predominating initial loss of CH 3 NCO exclusively involves the 3‐ and 4‐positions, for which an asynchronous mechanism is discussed.