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Efficient analyte oxidation in an electrospray ion source using a porous flow-through electrode emitter.
Gary J Van Berkel1, Vilmos Kertesz, Michael J Ford
1Organic and Biological Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd., Bldg. 5510, Oak Ridge, TN 37831-6131, USA. vanberkelgj@ornl.gov
Journal of the American Society for Mass Spectrometry
|December 14, 2004
Summary
A novel porous electrode emitter enhances electrospray ionization by improving analyte oxidation. Adjusting current flow allows precise control over oxidation extent and ion abundance in mass spectrometry.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Mass Spectrometry
Background:
- Electrospray ionization (ESI) is a crucial technique for analyzing non-volatile compounds.
- Efficient analyte oxidation in ESI often faces limitations due to current density and mass transport.
- Developing advanced emitter designs is essential for improving ESI performance.
Purpose of the Study:
- To introduce and characterize a porous flow-through electrode emitter for electrospray ionization.
- To investigate the enhancement of analyte oxidation through improved mass transport and controlled current.
- To demonstrate the tunable oxidation capabilities for controlling analyte ion abundance and type.
Main Methods:
- Design and fabrication of a porous flow-through electrode emitter.
- Integration of an upstream current loop to control electrode current.
- Electrochemical oxidation of model analytes (reserpine, ferroceneboronate derivative) at varying flow rates (up to 800 microL/min).
- Analysis using mass spectrometry (MS) coupled with flow injection, continuous infusion, and online HPLC.
Main Results:
- The porous emitter geometry significantly enhanced mass transport to the electrode surface.
- The upstream current loop effectively controlled the electrode current, overcoming oxidation limitations.
- Tunable analyte oxidation was achieved by adjusting the loop resistance, influencing ion abundance and product distribution.
- Successful demonstration of multiple electron transfer reactions and radical cation formation.
Conclusions:
- The porous flow-through electrode emitter offers a robust platform for efficient and controlled analyte oxidation in electrospray ionization.
- This design enables fine-tuning of oxidation extent, providing greater control over analyte ionization and MS detection.
- The approach holds promise for advancing quantitative and qualitative analyses in various chemical and biological applications.