INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
Differentiation of isomeric hydroxypyridine N-oxides using metal complexation and electrospray ionization mass spectrometry
MATIAS BUTLER, PAU ARROYO, GABRIELA M. CABRERA
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
ELSEVIER SCIENCE INC
Lugar: Oxford; Año: 2011 vol. 22 p. 545 - 545
Differentiation between two isomers of hydroxypyridine N-oxide according to the metal cationadducts generated by electrospray ionization (ESI) was investigated for different metal cations,namely Mg (II), Al (III), Ca (II), Sc (III), Fe (III), Co (II), Ni (II), Cu (II), Zn (II), Ga (III), besides thediatomic cation VO(IV). Protonated molecules of the isomeric hydroxypyridine N-oxides as wellas the singly/doubly charged adducts formed from neutral or deprotonated ligands and a doubly/triply charged cation were produced in the gas phase using ESI, recording mass spectra withdifferent metal ions for each isomer. While complex formation was successful for 2-hydroxypyridine N-oxide with trivalent ions, in the case of 3-hydroxypyridine N-oxide, onlypeaks related to the protonated molecule were present. On the other hand, divalent cationsformed specific species for each isomer, giving characteristic spectra in every case. Hence,differentiation was possible irrespective of the metal cation utilized. In addition, quantumchemical calculations at the B3LYP/6-31+G(d,p) level of theory were performed in order to gaininsight into the different complexation of calcium(II) with the isomers of hydroxypyridine N-oxide.The relative stability in the gas phase of the neutral complexes of calcium made up of twoligands, as well as the singly charged and doubly charged complexes, was investigated. Theresults of these calculations improved the understanding of the differences observed in the massspectra obtained for each isomer.