Contrast-enhanced differential mobility-desorption electrospray ionization-mass spectrometry imaging of biological tissues

Anal Chem. 2014 Apr 15;86(8):3756-63. doi: 10.1021/ac5007816. Epub 2014 Mar 31.

Abstract

Mass spectrometry imaging (MSI) performed under ambient conditions is a convenient and information-rich method that allows for the comprehensive mapping of chemical species throughout biological tissues with typical spatial resolution in the 40-200 μm range. Ambient MSI methods such as desorption electrospray ionization (DESI) eliminate necessary sample preparation but suffer from lower spatial resolution than laser-based and vacuum techniques. In order to take advantage of the benefits of ambient imaging and to compensate for the somewhat limited spatial resolution, a secondary orthogonal separation nested in the imaging scheme was implemented for more selective discernment of tissue features in the spectral domain. Differential mobility spectrometry (DMS), an ion mobility-based separation that selectively transmits ions based on their high-to-low electric field mobility differences, can significantly reduce background chemical interferences, allowing for increased peak capacity. In this work, DESI DM-MSI experiments on biological tissue samples such as sea algae and mouse brain tissue sections were conducted using fixed DMS compensation voltages that selectively transferred one or a class of targeted compounds. By reducing chemical noise, the signal-to-noise ratio was improved 10-fold and the image contrast was doubled, effectively increasing image quality.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Brain Chemistry
  • Chlorophyta / chemistry
  • Electromagnetic Fields
  • Image Processing, Computer-Assisted
  • Mice
  • Plants / chemistry
  • Rats
  • Signal Processing, Computer-Assisted
  • Signal-To-Noise Ratio
  • Spectrometry, Mass, Electrospray Ionization / methods*