Separation of intermediates of iron-catalyzed dopamine oxidation reactions using reversed-phase ion-pairing chromatography coupled in tandem with UV-visible and ESI-MS detections

J Chromatogr B Analyt Technol Biomed Life Sci. 2012 Dec 12;911:55-8. doi: 10.1016/j.jchromb.2012.10.026. Epub 2012 Oct 29.


Reversed-phase ion-pairing chromatography (RP-IPC) is coupled on-line with electrospray ionization-mass spectrometry (ESI-MS) through an interface comprising a four-way switch valve and an anion exchange column. Regeneration of the anion exchange column can be accomplished on-line by switching the four-way switch valve to interconnect the column to a regeneration solution. Positioning the anion exchange column between the RP-IPC and ESI-MS instruments allows the ion-pairing reagent (IPR) sodium octane sulfonate to be removed. The IPC-ESI-MS method enabled us to separate and detect four intermediates of the Fe(III)-catalyzed dopamine oxidation. In particular, 6-hydroxydopamine, which is short-lived and highly neurotoxic, was detected and quantified. Together with the separation of other intermediates, gaining insight into the mechanism and kinetics of the Fe(III)-catalyzed dopamine oxidation becomes possible.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Chromatography, Ion Exchange / methods
  • Chromatography, Reverse-Phase / methods*
  • Dopamine / analogs & derivatives*
  • Dopamine / analysis
  • Dopamine / chemistry*
  • Dopamine / isolation & purification
  • Iron / chemistry*
  • Oxidation-Reduction
  • Oxidopamine / chemistry
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Spectrophotometry, Ultraviolet


  • Oxidopamine
  • Iron
  • Dopamine