ANALYSIS OF PYRIDINOLINE AND ITS DERIVATIVES BY SCANNING-ARRAY 4-SECTOR TANDEM MASS-SPECTROMETRY

Structures of the trifunctional crosslink molecules, pyridinoline, deo xypyridinoline and glucosylgalactosyl-pyridinoline, have been characte rized by positive-ion liquid secondary-ion mass spectrometry (LSIMS) a nd collision-induced dissociation with scanning-array four-sector tand em mass spectrometry. It has been found that: (i) the naturally occurr ing cations (Cat+) are readily desorbed by positive-ion LSIMS utilizin g glycerol + thioglycerol (1:1) as liquid matrix and dominate the spec tra, facilitating accurate mass measurement; (ii) changing the matrix to 3-nitrobenzyl alcohol leaves little evidence of the cation, and (ii i) collision-induced dissociation of the cations (Cat+) of pyridinolin e, deoxypyridinoline and glucosylgalactosyl-pyridinoline gives a wealt h of fragmentation for structure elucidation. These fundamental studie s of tandem mass spectra of the known trifunctional crosslink molecule s provided valuable structure-related information, which help in the i dentification of the tissue-specific peptides containing these crossli nks. Artefact ions in these tandem mass spectra are remarkably abundan t.