Using the Electrochemistry of the Electrospray Ion Source
- ORNL
Electrospray mass spectrometry (ES-MS) is one of the more widely used analysis methods in science today, impacting fields as diverse as conventional chemistry to biotechnology and materials science. , Even 20 years after bursting onto the mass spectrometry scene, the underlying processes in ES ionization continue to be better understood exposing new opportunities for the technique. , , , , Such is the case for the improved understanding related to the electrochemical processes inherent to the operation of this ion source, , , which is the topic of this report. Electrospray ionization involves three main steps prior to mass analysis: the generation and charging of the ES droplets; droplet evaporation and the production of gas-phase ions; and secondary processes that modify the gas-phase ions in the atmosphere and the sub-atmospheric pressure sampling regions of the mass spectrometer. Integral to the generation and charging of the ES droplets are electrochemical reactions that occur at the conductive contact/solution interface within or near the ES emitter to maintain the quasi-continuous production of charged droplets and ultimately gas-phase ions. The basic electrochemical phenomena concerning the ES ion source were first brought to wide attention in the mass spectrometry community by Kebarle and co-workers in the early 1990's,8 but the electrochemistry of electrostatic spray devices and possible analytical consequences resulting from this phenomenon were realized and discussed in the literature at least as far back as the mid-1970's. When asked to intercede in a debate on the significance of electrochemistry in the ES ionization (ESI) process, 2002 Nobel Laureate in Chemistry John Fenn noted that to him " the idea that electrochemical reactions might be taking place in an ES ion source was too obvious to mention. That products of such reactions are of vital significance in the overall ESI process was much less obvious. Indeed, it seems fair to say that with few exceptions the products of the electrochemical reactions have been of only minor significance in most applications of ESI-MS. However, those exceptions have turned out to be of great interest and importance."10
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 930896
- Journal Information:
- Analytical Chemistry, Vol. 79, Issue 15
- Country of Publication:
- United States
- Language:
- English
Similar Records
A critical analysis of electrospray techniques for the determination of accelerated rates and mechanisms of chemical reactions in droplets
Ionization and transmission efficiency in an electrospray ionization-mass spectrometry interface