Photochemical and Thermal Stability of Some Dihydroxyacetophenones Used as UV-MALDI-MS Matrices

TARZI, OLGA; DI STEFANO, LUCIANO; ARGÜELLO, JUAN E.; OKSDATH-MANSILLA GABRIELA; ERRA-BALSELLS, ROSA

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2013 p. 1368 - 1368

0031-8655

,4-, 2,5-, 2,6- and 3,5-dihydroxyacetophenone (DHA) used as matrices in matrix-assisted ultraviolet laser desorption/ionization mass spectrometry (UV-MALDI-MS) were studied by steady-state and transient absorption spectroscopy, together with DFT calculations at the B3LYP level of theory. All compounds have low _uorescence quantum yields, possibly due to an ef_cient excited-state intramolecular proton transfer (ESIPT). Laser _ash photolysis (LFP) results showed that, only for 2,4-DHA, a phototautomer could be detected at k = 400 nm. Their photochemical stability in solution at different wavelengths and conditions was analyzed by UV?Vis and 1H nuclear magnetic resonance spectroscopy (1H-NMR), together with thin layer chromatography and ultraviolet laser desorption/ionization mass spectrometry (UV-LDI-MS). Only 3,5-DHA showed decomposition when irradiated, probably because phototautomerization is not possible. Thermal stability studies of these compounds in solid state were also conducte