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Identification of amino sugars from bacterial lipopolysaccharides by gas chromatography electron impact and chemical ionization mass spectrometry
Author(s) -
Bowser D. V.,
Teece R. G.,
Somani S. M.
Publication year - 1978
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.1200051107
Subject(s) - chemistry , muramic acid , mass spectrometry , chemical ionization , electron ionization , chromatography , hydrolysis , amino sugar , hexosamines , fast atom bombardment , organic chemistry , ionization , glucosamine , ion , enzyme , peptidoglycan
Amino sugars isolated from lipopolysaccharides of Brucella suis , Brucella abortus and Neisseria gonorrhoeae colony types 1 and 4 were identified using gas chromatography electron impact and chemical ionization mass spectrometry. Lipopolysaccharides were obtained by aqueous ether or aqueous phenol extraction. Isolated lipopolysaccharides were hydrolyzed in 1% acetic acid followed by hydrolysis of the polysaccharide moiety in 2 N HCI for 6 h at 100 °C. Amino sugars were first isolated by elution from Dowex 50 H + and then N ‐acetylated, followed by trimethylsilylation. Trimethylsilyl ethers of 2‐acetamido‐2‐deoxysugars; N ‐acetylglucosamine, N ‐acetylmannosamine, N ‐acetylgalactosamine, and a 2‐acetamido‐2,6‐dideoxysugar, N ‐acetylquinovosamine, were identified by their fragmentation patterns. In the electron impact mode, N ‐acetylglucosamine and N ‐acetyl‐galactosamine were distinguished from one another by comparing peak intensities at m / e 233 and 305. However, N ‐acetylglucosamine and N ‐acetylmannosamine could not be differentiated by electron impact mass spectrometry. In the chemical ionization mode, N ‐acetylglucosamine and N ‐acetylmannosamine both with base peaks at m/e 494, could be distinguished from N ‐acetylgalactosamine and N ‐acetylquinovosamine by their base peaks at m/e 420 and 332, respectively. N ‐Acetylglucosamine and N ‐acetylmannosamine were differentiated from one another by comparing peak intensities at m / e 330, 404, 420, and 510 [MH] + . This is the first report of chemical ionization mass spectrometry applied to the identification of amino sugars in bacterial lipopolysaccharides and shows that some 2‐amino‐2‐deoxysugars can be differentiated by both electron impact and chemical ionization mass spectrometry.