Open AccessCharacterization of ethyl chloroformate derivative of β-methylamino-l -alanine
Author(s) -
Tao Guo,
Steve Geis,
Curtis J. Hedman,
Michael Arndt,
William Krick,
William C. Sonzogni
Publication year - 2007
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2007.01.006
Subject(s) - chemistry , fragmentation (computing) , mass spectrometry , chloroformate , electron ionization , mass spectrum , ethyl chloroformate , derivative (finance) , alanine , cleavage (geology) , amino acid , chemical ionization , stereochemistry , carboxylic acid , cyanobacteria , chromatography , ion , organic chemistry , ionization , biochemistry , geotechnical engineering , fracture (geology) , biology , computer science , bacteria , financial economics , engineering , economics , genetics , operating system
Beta-methylamino-L-alanine (BMAA) is a neurotoxic amino acid that can be produced by cyanobacteria in aqueous environments. To analyze this compound by gas chromatography/mass spectrometry (GC/MS), BMAA must be derivatized to a nonpolar, volatile compound. This can be accomplished by reacting BMAA with ethyl chloroformate. While carrying out electron ionization (EI) mass spectrometric analysis on the (13)C-labeled derivative, it was discovered that the formation of an ion with a peak at m/z 245.12 is the result of [CH(3)CH(2)O.] loss from the amino groups resulting from alpha-cleavage. This differs from previous reports that attributed this peak to alpha-cleavage of the carboxylic ester portion of the BMAA derivative. This finding is important for understanding BMAA derivative mass spectrometric fragmentation patterns and ultimately to properly identifying and quantifying BMAA. Fragmentation pathways for the formation of other major peaks observed in the EI mass spectra are also proposed.