Electron ionisation and electrospray ionisation mass spectrometric study of a series of isomeric methyl-, dimethyl- and trimethylalloxazines.
Electron ionisation (EI) mass spectra and electrospray ionisation (ESI) mass spectra at different cone voltages of a series of isomeric methyl- and dimethylalloxazines are discussed, and compared with those of lumichrome, and 1- and 3-methyllumichrome. Examination of ESI mass spectra taken at a higher cone voltage and the use of isotope-labelled methanol allow us to discuss the fragmentation pathways of [M+H]+ and [M-H](-) ions. The fragmentation pathways of all of the compounds and the characteristic fragment ions formed in EI-MS are compared with published data. The influence of methyl and dimethyl substituents in the benzene ring on the fragmentation pathways leading to the loss of 43 and 45 Da upon both electron and electrospray ionisation is described.
Prukała
Dorota
D
Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland. dprukala@amu.edu.pl
Prukała
Wiesław
W
Koczorowski
Ryszard
R
Khmelinskii
Igor V
IV
Sikorska
Ewa
E
Sikorski
Marek
M
D004583:Electrons; D005415:Flavins / Q000032:analysis* / Q000737:chemistry*; D007477:Ions; D007536:Isomerism; D008745:Methylation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D005415:Flavins; D007477:Ions; C008173:isoalloxazine