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Electrospray MS‐based characterization of β‐carbolines – mutagenic constituents of thermally processed meat
Author(s) -
Crotti Antônio Eduardo Miller,
Gates Paul J.,
Lopes João Luis Callegari,
Lopes Norberto Peporine
Publication year - 2010
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200900064
Subject(s) - indole test , chemistry , electrospray , fragmentation (computing) , mass spectrometry , molecule , protonation , ion , electrospray ionization , tandem mass spectrometry , polyatomic ion , amine gas treating , chromatography , stereochemistry , organic chemistry , computer science , operating system
The β‐carbolines 1‐methyl‐9 H ‐pyrido [3,4‐ b ]indole and 9 H ‐pyrido[3,4 b ]indole have been implicated as having causative roles in a number of human diseases, such as Parkinson's disease and cancer. As they can be formed during the heating of protein‐rich food, a number of analytical methodologies have been proposed for their detection and quantification in foodstuff. For this purpose, LC‐MS and LC‐MS/MS have emerged as the most specific analytical methods, and the quantification is based on the occurrence of unusual ions, such as [M+H‐(H • )] + and [M+H‐2H] + . In this study, we have investigated the formation of these ions by accurate‐mass electrospray MS/MS and demonstrated that these ions are formed from gas‐phase ion‐molecule reactions between water vapor present in the collision cell and the protonated molecule of 1‐methyl‐9 H ‐pyrido [3,4‐ b ]indole and 9 H ‐pyrido[3,4 b ]indole. Although this reaction has been previously described for heterocyclic amine ions, it has been overlooked in the most of recent LC‐MS and LC‐MS/MS studies, and no complete data of the fragmentation are reported. Our results demonstrate that additional attention should be given with respect to eliminating water vapor residues in the mass spectrometer when analysis of β‐carbolines is performed, as this residue may affect the reliability in the results of quantification.