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Updated: Jun 24, 2026

Profiling Thiol Redox Proteome Using Isotope Tagging Mass Spectrometry
Published on: March 24, 2012
Electrochemically initiated tagging of thiols using an electrospray ionization based liquid microjunction surface
Gary J Van Berkel1, Vilmos Kertesz
1Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6131, USA. vanberkelgj@ornl.gov
This study converted a liquid microjunction surface sampling probe (LMJ-SSP) into an electrochemical cell for analyte tagging. This novel electrochemical surface sampling method achieved efficient peptide cysteine tagging with hydroquinone tags.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Surface Science
Background:
- Liquid microjunction surface sampling probes (LMJ-SSP) are used for surface analysis.
- Electrochemical tagging offers a sensitive method for analyte functionalization.
Purpose of the Study:
- To adapt an LMJ-SSP into a two-electrode electrochemical cell.
- To investigate the electrochemical tagging of peptide cysteine residues with hydroquinone tags.
Main Methods:
- Conversion of LMJ-SSP into a two-electrode electrochemical cell.
- Electrochemical initiation of hydroquinone tagging of thiol functionalities.
- Analysis of tagging efficiency at various flow rates.
Main Results:
- Achieved approximately 90% tagging efficiency for peptide cysteine residues.
- Demonstrated efficient tagging for up to two cysteines per peptide.
- Validated a simple kinetic model to explain high tagging efficiency.
Conclusions:
- The adapted LMJ-SSP enables efficient electrochemical tagging of analytes sampled from surfaces.
- Incorporating electrochemical capabilities enhances the versatility of LMJ-SSP for mass spectrometry-based analysis.
- This approach expands the utility of surface sampling techniques for detailed molecular analysis.
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