| Abstract: | Application of pyrolysis-desorption chemical ionization mass spectrometry (Py-DCI-MS) is demonstrated for the structural characterization of the native O-specific antigen of Yersinia ruckeri. Under proper pyrolytic and chemical ionization conditions this antigenic polysaccharide yields anhydrohexosamine fragments which facilitate identification of the trimeric repeating unit sequence. Tandem mass spectrometric analyses of the trimeric repeating unit fragments provided additional evidence for the proposed structure and permitted rationalization of the observed fragment ions. Furthermore, Py-DCI-MS of smaller hexosamine subunits isolated during off-line pyrolysis experiments showed fragmentation characteristics almost identical with those observed in the mass spectra of the whole antigen, hence confirming the stability of the pyrolysis fragments. |
