Atmospheric pressure photoionization of peptides

In this work, fragmentations of peptides under atmospheric pressure photoionization conditions are further investigated for a model peptide. In the positive ion mode, intensive fragmentations are observed, mainly ascribed to c-sequence ions along with less abundant a- and b- type ions. The same features and c- ion series are reported for the negative ion mode, thereby suggesting a common mechanistic origin for the fragmentation in both ion modes. Moreover, it is shown that ECD-like fragmentation under APPI conditions may retain non-covalent adducts. This interesting property positions APPI as a promising ECD-like technique for in-source top down sequencing.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (142 K)Download as PowerPoint slideResearch highlights▶ Peptide. ▶ Positive & Negative ion mode APPI. ▶ Positive & Negative c-fragment ions.