UV-MALDI-TOF MS analysis of carbohydrates. Reviewing comparative studies using nor-harmane and several classical matrices

ERRA BALSELLS, R., NONAMI, H.,; ROSA ERRA-BALSELLS

Environmental Control in Biology

Yokendo

Lugar: Tokyo; Año: 2008 vol. 46 p. 65 - 90

0582-4087

   In an effort to gain an understanding of the processes governing matrix-assisted ultraviolet laser desorption/ionization (UV-MALDI), we made a direct comparison of the mass spectra (MS) of carbohydrates (neutral cyclic and acyclic, sulfated and acid mono- and polysaccharides) by using nor-harmane and several classical matrices (gentisic acid (GA); 2,4,6-trihydroxixyacetophenone (THAP); among others) as UV-MALDI matrices in positive and negative ion modes in linear, reflectron and post-source decay (PSD) modes.     The peculiarity of nor-harmane is that behaves  better as matrix than GA in negative ion mode. Because the initiation of the UV-MALDI process is a photochemical  reaction  (matrix + hn (337 or 355 nm) ® matrix*), the acid-base character of nor-harmane in the ground and the lower electronic excited singlet state, together with other photophysical properties such as prompt heat release to the medium are discussed in brief.     Excellent results obtained with cyclodextrins with nor-harmane allow us to propose these analyte-matrix systems for UV-MALDI-TOF MS calibration in positive and negative ion modes in linear, reflectron and PSD modes.