Characterization of photo-induced pyrimidine cyclobutane dimers by laser desorption Fourier transform mass spectrometry.
Laser desorption Fourier transform mass spectrometry was used to characterize the cis-syn cyclobutane photodimers of uracil-uracil, uracil-thymine and thymine-thymine. This soft ionization technique generated [M-H]- ions as well as some fragment ions. Investigation of the laser desorption process indicated that gas-phase dimerization reactions do not occur for pyrimidine monomers and dimers under these experimental conditions. Collisional dissociation of the [M-H]- ions provided structural information for the pyrimidine rings of the dimers. The fragment ions observed in the collisional dissociation spectra of these cyclobutane dimers suggested rearrangement of the [M-H]- parent ions to a macrocycle prior to dissociation.
Hettich
R L
RL
Analytical Chemistry Division, Oak Ridge National Laboratory, Tennessee 37831-6120.
Buchanan
M V
MV
Ho
C H
CH
D003503:Cyclobutanes; D005583:Fourier Analysis; D007834:Lasers; D013058:Mass Spectrometry; D010777:Photochemistry; D011740:Pyrimidine Dimers / Q000032:analysis* / Q000528:radiation effects; D013941:Thymine / Q000032:analysis; D014466:Ultraviolet Rays; D014498:Uracil / Q000032:analysis
D003503:Cyclobutanes; D011740:Pyrimidine Dimers; D014498:Uracil; D013941:Thymine