Bacterial Analysis by Ambient Ionization Techniques

Method(s) of Analysis:

  • Desorption Electrospray Ionization (DESI) – optimal for condensed phase samples
  • Extractive Electrospray Ionization (EESI) - optimal for solution phase samples

Both offer:

  • Rapid Analysis (High Throughput)
  • Minimal Sample Preparation
  • Sensitive
  • Reproducible


Key Findings:

Monitoring of Central Carbon E. coli Metabolites by DESI and EESI

  • Targeted  analysis of central carbon metabolites using MS/MS
  • Identification of 13C labeled metabolites
  • Ambient chemical reactions to enhance  selectivity
  • Potential to explore in-situ targeted metabolomics

Analysis of Fresh Intact Bacteria

  • Highly reproducible spectra achieved
  • PCA allows subspecies differentiation
  • Able to distinguish ~20 strains

Analysis of Bacterial Biofilms

  • Rapid analysis of live organisms from intact biofilms
  • PCA allows subspecies differentiation
  • Lipid profiles in both positive and negative ion modes identified



  • Zhang, J. I.; Talaty, N.; Costa, A.; Tao, W.A.; Cooks, R. G.; "Profiling Intact Untreated Bacteria Using Desorption Electrospray Ionization (DESI)" In preparation.
  • Talaty, N.; Song, Y.; Hsieh, Y.; Datsenko, K. A.; Wanner, B.L.; Cooks, R.G. "Rapid in vivo Analysis of Biofilms by Desorption Electrospray Ionization (DESI)" In preparation.
  • Ayanna U. Jackson, Sean R. Werner, Nari Talaty, Yishu Song, Karinna Campbell, John A. Morgan, R. Graham Cooks, "Targeted Metbolomic Analysis of Escherichia coli by Desorption Electrospray Ionization and Extractive Electrospray Ionization Mass Spectrometry", Analytical Biochemistry, 2008, 375 (2), 272-281,
  • Yishu Song, Nari Talaty, Andy W. Tao, Zhengzheng Pan and R. Graham Cooks, "Rapid Ambient Mass Spectrometric Profiling of Intact, Untreated Bacteria using Desorption Electrospray Ionization", Chemical Communications, 2007, 61-63, doi: 10.1039/b615724f