Biological processes can be very dynamic and characterization of the reaction intermediates along the reaction path together with the kinetic profiles is important to fully understand the reaction mechanism. Time-dependent mass spectrometry measurements show several advantages over other techniques, such as conceptual simplicity, low sample concentrations, and speed, which allows capturing non-equilibrium states.

Michal Sharon, Weizmann Institute of Sciences, Rehovot, Israel, and colleagues have developed a rapid continuous-flow mixing apparatus for real-time electrospray mass spectrometry measurements. By minimizing metal-solution interfaces and by providing a sheath flow of nitrogen gas, a stable and continuous spray is achieved, which improves the signal-to-noise ratio.

According to the researchers, the device can easily replace commercial electrospray ionization sources on mass spectrometers. Improved signal-to-noise ratio and reduced experimental repeat errors were demonstrated with the unfolding reaction of cytochrome C.

• An Improved Rapid Mixing Device for Time-Resolved Electrospray Mass Spectrometry Measurements
  Nicholas Zinck, Ann-Kathrin Stark, Derek J. Wilson, Michal Sharon
  ChemistryOpen 2014.
  DOI: 10.1002/open.201402002