Facile Improvement of Negative Ion Mode Electrospray Ionization Using Capillary Vibrating Sharp-Edge Spray Ionization

Anal Chem. 2020 Feb 4;92(3):2492-2502. doi: 10.1021/acs.analchem.9b03983. Epub 2020 Jan 15.

Abstract

Electrospray ionization (ESI) is often affected by corona discharge when spraying 100% aqueous solutions as the voltage that induces discharge can be well below the onset voltage of ESI. As a result, it is especially challenging to perform native mass spectrometry in negative ion mode where 100% aqueous solution is preferred. Here we report a simple instrumentation method to improve the performance of ESI in negative ion mode based on capillary vibrating sharp-edge spray ionization. By attaching a fused silica capillary emitter to a vibrating glass slide, improved signal quality is achieved for various analytes in aqueous solutions over applying ESI alone. Compared to commercial ESI sources using nebulization gas to reduce discharge, 10-100-fold enhancement in signal intensity and 3-10-fold improvement in S/N are achieved for various kinds of molecules including DNA, peptides, proteins, and oligosaccharides. Finally, the new method demonstrates utility for native mass spectrometry analysis of proteins and G-quadruplex DNA. The present method is expected to have great potential to be adopted by the scientific community because of its improved analytical performance, simplicity, and low cost.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • DNA / analysis*
  • G-Quadruplexes
  • Proteins / analysis*
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Proteins
  • DNA