Premium
Amino acid mixture analysis by mass spectrometry in the form of their dimethylaminomethylene methyl esters
Author(s) -
Horman I.,
Hesford F. J.
Publication year - 1974
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200010206
Subject(s) - chemistry , amino acid , histidine , cystine , derivatization , tryptophan , methionine , mass spectrometry , organic chemistry , chromatography , cysteine , biochemistry , enzyme
The amino acids, arginine, citrulline, cysteine, cystine, histidine, hydroxyproline, methionine, ornithine, proline, serine, threonine, tryptophan and tyrosine, have been analysed in the form of their N ‐( N ′, N ′‐dimethylaminomethylene) methyl esters. formed in a single step by reaction of the free amino acid or its hydrochloride with N , N ‐dimethylformamide dimethylacetal in acetonitrile/methanol (2:1). A reaction time of 15 minutes at 100 °C ensures complete derivatization, the derivatives being volatile at source temperatures below 150 °C, and giving electron impact spectra characterized by abundant (or moderately abundant) peaks at or near the mass of the molecular ion. The analysis of amino acid mixtures by mass fragmentography on characteristic high mass peaks of their N ‐( N ′, N ′‐dimethylaminoethylene) methyl ester derivatives, introduced on a direct insertion probe and volatilized during temperature programming of the source, is qescribed. The method is applied to the analysis of a mixture containing arginine, citrulline, cystine, histidine and tryptophan, traditionally difficult to analyse by other methods.