Online Coupling of Electrochemical Reactions with Mass Spectrometry

Strategic Insights -

Recent research has reported a powerful analytical tool, combining electrochemistry and mass spectrometry, to study redox reactions. This innovation involves the online coupling of a thin-layer electrochemical flow cell with liquid sample desorption electrospray ionization mass spectrometry (DESI-MS). The direct sampling nature of DESI has several useful features, including fast response time, freedom to choose an ionization mode, and the absence of background signal when the cell is off. The researchers successfully applied this coupling apparatus to investigate various electrochemical reactions of biological molecules, such as the oxidative formation and reductive cleavage of disulfide bonds, and the online derivatization of peptides/proteins.

Key Takeaways:

  • The combination of electrochemistry and mass spectrometry is a powerful analytical tool for studying redox reactions, as demonstrated by the online coupling of a thin-layer electrochemical flow cell with DESI-MS.
  • This innovative approach has several useful features, including a fast response time of 3.6 s for dopamine oxidation, freedom to choose an ionization mode, and the absence of background signal when the cell is off.
  • The researchers successfully applied this coupling apparatus to investigate various electrochemical reactions of biological molecules, including the oxidative formation and reductive cleavage of disulfide bonds and the online derivatization of peptides/proteins.
  • The online tagging of free cysteine residues of peptides/proteins employing electrogenerated dopamine o-quinone can be performed using this method.
  • The study suggests that the EC/DESI-MS has good potential in bioanalysis, with applications in investigating various electrochemical reactions of biological molecules.
  • The researchers successfully detected both the A and B chains of insulin online by DESI-MS after the electrolytic reduction of its three disulfide bonds.
  • This innovative approach can be freely chosen as a favorable ionization mode of DESI or traditional electrolysis solvent systems.

Statistics:

  • The response time of the DESI-MS coupling was 3.6 s for dopamine oxidation.
  • The researchers successfully detected both the A and B chains of insulin online by DESI-MS after the electrolytic reduction of its three disulfide bonds.
  • The study suggests that the EC/DESI-MS has good potential in bioanalysis, with applications in investigating various electrochemical reactions of biological molecules.

Sources:

  • Analytical Chemistry, "Online Coupling of Electrochemical Reactions with Liquid Sample Desorption Electrospray Ionization-Mass Spectrometry", 2009;81(23):9716-9722
  • Ohio University, Dept. of Chemical & Biochemistry, Clippinger Laboratories, Center Intelligent Chemical Instrumentat, Athens, OH 45701, USA
  • American Chemical Society, 1155 16th St., NW, Washington, DC 20036, USA