Photochemical and Thermal Stability of some Dihydroxyacetophenones used as UV-MALDI-MS Matrices

GABRIELA OKSDATH MANSILLA

Photochemical and Photobiology

John Wiley and Sons

Año: 2013 vol. 89 p. 1368 - 1368

1751-1097

,4-, 2,5-, 2,6- and 3,5-dihydroxyacetophenone (DHA) used asmatrices in matrix-assisted ultraviolet laser desorption/ionizationmass spectrometry (UV-MALDI-MS) were studied bysteady-state and transient absorption spectroscopy, togetherwith DFT calculations at the B3LYP level of theory. All compoundshave low fluorescence quantum yields, possibly due toan efficient excited-state intramolecular proton transfer(ESIPT). Laser flash photolysis (LFP) results showed that, onlyfor 2,4-DHA, a phototautomer could be detected atk = 400 nm. Their photochemical stability in solution at differentwavelengths and conditions was analyzed by UV?Vis and1H nuclear magnetic resonance spectroscopy (1H-NMR),together with thin layer chromatography and ultraviolet laserdesorption/ionization mass spectrometry (UV-LDI-MS). Only3,5-DHA showed decomposition when irradiated, probablybecause phototautomerization is not possible.