Isomer differentiation of hydroxypyridine N-oxides using metal complexation and electrospray ionization mass spectrometry.

BUTLER, MATÍAS; ARROYO MAÑEZ PAU; CABRERA, GABRIELA M

Salt Lake City, Utah

Congreso; 58th ASMS Conference on Mass Spectrometry and Allied Topics; 2010

Possible differentiation between two isomers of hydroxypyridine N-oxide according to the cationized metal complexes generated by ESI was investigated for different metal cations.  Metal salts can either be mixed directly with the analytes prior to direct infusion or be introduced as a postcolumn complexation reagent after the compounds are separated by HPLC before entry into the ion source. As metal complexation was promising in differentiating both isomers, its practical application in LC/ESI-MS as a detection method for distinguishing them was tested. While complex formation was successful for 2-hydroxypyridine N-oxide with trivalent ions, in the case of 3-hydroxypyridine N-oxide, only peaks related to the protonated cation were present. On the other hand, divalent cations formed specific species for each isomer, giving characteristic spectra in every case.