Issue 10, 2016

Atmospheric-pressure ionization and fragmentation of peptides by solution-cathode glow discharge

Abstract

Modern “-omics” (e.g., proteomics, glycomics, metabolomics, etc.) analyses rely heavily on electrospray ionization and tandem mass spectrometry to determine the structural identity of target species. Unfortunately, these methods are limited to specialized mass spectrometry instrumentation. Here, a novel approach is described that enables ionization and controlled, tunable fragmentation of peptides at atmospheric pressure. In the new source, a direct-current plasma is sustained between a tapered metal rod and a flowing sample-containing solution. As the liquid stream contacts the electrical discharge, peptides from the solution are volatilized, ionized, and fragmented. At high discharge currents (e.g., 70 mA), electrospray-like spectra are observed, dominated by singly and doubly protonated molecular ions. At lower currents (35 mA), many peptides exhibit extensive fragmentation, with a-, b-, c-, x-, and y-type ion series present as well as complex fragments, such as d-type ions, not previously observed with atmospheric-pressure dissociation. Though the mechanism of fragmentation is currently unclear, observations indicate it could result from the interaction of peptides with gas-phase radicals or ultraviolet radiation generated within the plasma.

Graphical abstract: Atmospheric-pressure ionization and fragmentation of peptides by solution-cathode glow discharge

Supplementary files

Article information

Article type
Edge Article
Submitted
09 May 2016
Accepted
24 Jun 2016
First published
27 Jun 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2016,7, 6440-6449

Atmospheric-pressure ionization and fragmentation of peptides by solution-cathode glow discharge

A. J. Schwartz, J. T. Shelley, C. L. Walton, K. L. Williams and G. M. Hieftje, Chem. Sci., 2016, 7, 6440 DOI: 10.1039/C6SC02032A

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