Oxidation Artifacts in the Electrospray Mass Spectrometry of Aβ Peptide

Gradual corrosion of stainless steel electrospray emitters under conditions of normal use generates surface irregularities that can promote electrical discharge. The increased emission current affects the electrochemical reactions associated with the spray process. When sampling the peptide Aβ(1−40)...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2007-03, Vol.79 (5), p.2031-2036
Main Authors: Chen, Maolian, Cook, Kelsey D
Format: Article
Language:English
Subjects:
Analytical chemistry
Chemistry
Exact sciences and technology
Spectrometric and optical methods
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Summary:Gradual corrosion of stainless steel electrospray emitters under conditions of normal use generates surface irregularities that can promote electrical discharge. The increased emission current affects the electrochemical reactions associated with the spray process. When sampling the peptide Aβ(1−40), this is manifest by oxidation of methionine at position 35 to methionine sulfoxide. The resultant mass shift and reduced sensitivity can adversely affect H/D exchange experiments. These effects can be avoided by adding a redox buffer or (preferably) by repolishing the emitter, especially to a rounded geometry.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac061743r