Reduction of cationic free-base meso-tris-N-methylpyridinium-4-yl porphyrins in positive mode electrospray ionization mass spectrometry

  • Catarina I. V. Ramos
  • M. Graça Santana Marques
  • A. J. Ferrer Correia
  • Vanda Vaz Serra
  • João P. C. Tomé
  • Augusto C. Tomé
  • M. Graça P. M. S. Neves
  • J. A. S. Cavaleiro


Reductions involving more than one electron with formation of the M+ and [M+2H]+ ions were observed for electrosprayed meso-tris(N-methylpyridinium-4-yl)porphyrin iodides, MI3. These reductions were studied by using different solvents and flow rates. Formation of the [M+2H]+ ions occurred only for protic solvents and to a larger extent at lower flow rates. The type of the fourth substituent does not seem to affect the reduction processes. Formation of the two reduced species, M+ and [M+2H]+ ions, may occur through the participation of counter ion/solvent clusters. Reduction of multiply charged, non-metallated species with formation of [M+nH]+ ions (n>1) was not observed before in positive mode electrospray mass spectrometry.


Porphyrin Fast Atom Bombardment Electrospray Mass Spectrometry Diquat Cationic Porphyrin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Blades, A. T.; Ikonomou, M. G.; Kebarle, P. Mechanism of Electrospray Mass Spectrometry: Electrospray as an Electroysis Cell. Anal. Chem. 1991, 63, 2109–2114.CrossRefGoogle Scholar
  2. 2.
    Van Berkel, G. J. The Electrolytic Nature of Electrospray. In Electrospray Ionization Mass Spectrometry: Fundamentals, Instrumentation, and Applications, Cole, R. B., Ed.; John Wiley & Sons: New York, 1997; p 65.Google Scholar
  3. 3.
    De la Mora, J. F.; Van Berkel, G. J.; Enke, C. G.; Cole, R. B.; Martinez-Sanchez, M.; Fenn, J. B. Electrochemical Processes in Electrospray Ionization Mass Spectrometry. J. Mass Spectrom. 2000, 35, 939–952.CrossRefGoogle Scholar
  4. 4.
    Van Berkel, G. J.; McLuckey, S. A.; Glish, G. L. Electrospray Ionization of Porphyrins Using a Quadrupole Ion Trap for Mass Analysis. Anal. Chem. 1991, 63, 1098–1109.CrossRefGoogle Scholar
  5. 5.
    Van Berkel, G. J.; Zhou, F. Characterization of an Electrospray Ion Source as a Controlled-Current Electrolytic Cell. Anal. Chem. 1995, 67, 2916–2923.CrossRefGoogle Scholar
  6. 6.
    Van Berkel, G. J.; Zhou, F. Observation of Gas-Phase Molecular Dications Formed from Neutral Organics in Solution via the Controlled-Current Electrolytic Process Inherent to Electrospray. J. Am. Soc. Mass Spectrom. 1996, 7, 157–162.CrossRefGoogle Scholar
  7. 7.
    Van Berkel, G. J.; Quirke, J. M. E.; Tigani, R. A.; Dilley, A. S.; Covey, T. R. Derivatization for Electrospray Mass Spectrometry. 3: Electrochemically Ionizable Derivatives. Anal. Chem. 1998, 70, 1544–1554.CrossRefGoogle Scholar
  8. 8.
    Van Berkel, G. J. Insights into Analyte Electrolysis in an Electrospray Emitter from Chronopotentiometry Experiments and Mass Transport Calculations. J. Am. Soc. Mass Spectrom 2000, 11, 951–960.CrossRefGoogle Scholar
  9. 9.
    Rohner, T. C.; Lion, N.; Girault, H. H. Electrochemical and Theoretical Aspects of Electrospray Ionisation. Phys. Chem. Chem. Phys. 2004, 6, 3056–3058.CrossRefGoogle Scholar
  10. 10.
    Diehl, G.; Karst, U. On-line Electrochemistry—MS and Related Techniques. Anal. Bioanal. Chem. 2002, 373, 390–398.CrossRefGoogle Scholar
  11. 11.
    Milman, B. L. Cluster Ions of Diquat and Paraquat in Electrospray Mass Spectra and their Collision-induced Dissociation Spectra. Rapid Commun. Mass Spectrom. 2003, 17, 1344–1349.CrossRefGoogle Scholar
  12. 12.
    Song, X.; Budde, W. Capillary Electrophoresis-Electrospray Mass Spectra of the Herbicides Paraquat and Diquat. J. Am. Soc. Mass Spectrom. 1996, 7, 981–986.CrossRefGoogle Scholar
  13. 13.
    Moyano, E.; Games, D. E.; Galceran, M. T. Determination of Quaternary Ammonium Herbicides by Capillary Electrophoresis/Mass Spectrometry. Rapid Commun. Mass Spectrom. 1996, 10, 1379–1385.CrossRefGoogle Scholar
  14. 14.
    Bigey, P.; Frau, S.; Loup, C.; Claparols, C.; Bernadou, J.; Meunier, B. Preparation and Characterization by Electrospray Mass Spectrometry of Cationic Metalloporphyrin DNA Cleavers. Bull. Soc. Chim. Fr. 1996, 133, 679–689.Google Scholar
  15. 15.
    Batinic-Haberle, I.; Stevens, R. D.; Fridovich, I. Electrospray Mass Spectrometry of Isomeric Tetrakis(N-alkylpyridyl)porphyrins and Their Manganese(III) and Iron(III) Complexes. J. Porphyrins Phthalocyanins 2000, 4, 217–227.CrossRefGoogle Scholar
  16. 16.
    Kachadourian, R.; Srinivasan, N.; Haney, C. A.; Stevens, R. D. An LDI-TOF and ESI Mass Spectrometry Study of a Series of beta-Substituted Cationic Metalloporphyrins. J. Porphyrins Phthalocyanins 2001, 5, 507–511.CrossRefGoogle Scholar
  17. 17.
    Batinic-Haberle, I.; Spasojevic, I.; Stevens, R. D.; Hambright, P.; Fridovich, I. Manganese(III) meso-Terakis(ortho-N-alkylpyridyl)porphyrins: Synthesis, Characterization and Catalysis of O2 Dismutation. J. Chem. Soc. Dalton Trans 2002, 2689–2696.Google Scholar
  18. 18.
    Cerny, R. L.; Gross, M. L. Abundances of Molecular Ion Species Desorbed by Fast Atom Bombardment: Observation of (M+2H)+ and (M+3H)+. Anal. Chem. 1985, 57, 1160–1163.CrossRefGoogle Scholar
  19. 19.
    Musselman, B. D.; Watson, J. T. Observation of Solvent Effects on Abundance of Polyhydrogen Adducts (M+nH)+ in Fast Atom Bombardment Mass Spectrometry. Biomed. Environ. Mass Spectrom. 1987, 14, 247–248.CrossRefGoogle Scholar
  20. 20.
    Vekey, K. Interference Effects Caused by Oxidation and Reduction Processes in Fast Atom Bombardment Mass-Spectrometry. Int. J. Mass Spectrom. Ion Proc. 1990, 97, 265–282.CrossRefGoogle Scholar
  21. 21.
    Ohashi, Y.; Itoh, I. Unprecedented Matrix Induced Reduction of Flavins Observed under FAB and MALDI Conditions. Curr. Org. Chem. 2003, 7, 1605–1611.CrossRefGoogle Scholar
  22. 22.
    Lindsey, J. S. Synthesis of meso-Substituted Porphyrins. In The Porphyrin Handbook—Synthesis and Organic Chemistry, Vol. 1, Kadish, K. M.; Smith, K. M., Guilard, R., Eds.; Academic Press: London, UK, 45.Google Scholar
  23. 23.
    Tomé, J. P. C.; Neves, M. G. P. M. S.; Tomé, A. C.; Cavaleiro, J. A. S.; Soncin, M.; Magaraggia, M.; Ferro, S.; Jori, G. Synthesis and Antibacterial Activity of New Poly-S-lysine-Porphyrin. J. Med. Chem. 2004, 47, 6649–6652.CrossRefGoogle Scholar
  24. 24.
    Tomé, J. P. C.; Mendonça, A. F.; Neves, M. G. P. M. S.; Tomé, A. C.; Valdeira, M. L.; Cavaleiro, J. A. S. PT Patent 2001, 102, 572.Google Scholar
  25. 25.
    Ryan, T. M.; Day, R. J.; Cooks, R. G. Secondary Ion Mass-Spectra of Diquaternary Ammonium-Salts. Anal. Chem. 1980, 52, 2054–2057.CrossRefGoogle Scholar
  26. 26.
    Vincze, A.; Busch, K. L.; Cooks, R. G. Secondary Ion Mass-Spectra of Quaternary Pyridine Aldoximes. Anal. Chim. Acta 1982, 136, 143–153.CrossRefGoogle Scholar
  27. 27.
    Heller, D. N.; Yergey, J.; Cotter, R. J. Doubly Charged Ions in Desorption Mass Spectrometry. Anal. Chem. 1983, 55, 1310–1313.CrossRefGoogle Scholar
  28. 28.
    Clayton, E.; Wakefield, A. J. C. Fast Atom Bombardment (F.A.B.) Mass Spectrometry; Mechanism of Ionisation. J. Chem. Soc. Chem. Commun. 1984,, 969–970.Google Scholar
  29. 29.
    Claereboudt, J.; Baeten, W.; Geise, H.; Claeys, M. Structural Characterization of Mono- and Bisphosphonium Salts by Fast Atom Bombardment Mass Spectrometry and Tandem Mass Spectrometry. Org. Mass Spectrom. 1993, 28, 71–82.CrossRefGoogle Scholar
  30. 30.
    Kunkel, G. J.; Busch, K. L.; Dunphy, R.; Burinsky, D. J.; Barak, R.; Bel, P.; Amitai, G.; Vincze, A. Liquid Secondary Ion Mass Spectra and Fast Atom Bombardment Mass Spectra of Diquaternary Pyridinium Oxime Salts. J. Mass Spectrom. 1995, 30, 282–290.CrossRefGoogle Scholar
  31. 31.
    Marr, J. C.; King, J. B. A Simple High Performance Liquid Chromatography/Ionspray Tandem Mass Spectrometry Method for the Direct Determination of Paraquat and Diquat in Water. Rapid Commun. Mass Spectrom. 1997, 11, 479–483.CrossRefGoogle Scholar
  32. 32.
    Lazar, A. C.; Reilly, P. T. A.; Whitten, W. B.; Ramsey, J. M. Laser Desorption/Ionization Coupled to Mass Spectrometry for Real-time Monitoring of Paraquat on the Surface of Environmental Particles. Rapid Commun. Mass Spectrom. 2000, 14, 1523–1529.CrossRefGoogle Scholar
  33. 33.
    Smith, K. M. Porphyrins and Metalloporphyrins, Elsevier Scientific: Amsterdam, The Netherlands, 1975; pp 19–27.Google Scholar
  34. 34.
    Hashimoto, T.; Choe, Y.-K.; Nakano, H.; Hirao, K. Theoretical Study of the Q and B Bands of Free-base, Magnesium and Zinc Porphyrins and Their Derivatives. J. Phys. Chem. 1999, 103, 1894–1904.CrossRefGoogle Scholar
  35. 35.
    Wang, G.; Cole, R. B. Effects of Solvent and Counterion on Ion Pairing and Observed Charge States of Diquaternary Ammonium Salts in Electrospray Mass Spectrometry. J. Am. Soc. Mass Spectrom. 1996, 7, 1050–1058.CrossRefGoogle Scholar
  36. 36.
    Christie, C. G. A Predictive Model for Matrix and Analyte Effects in Electrospray Ionization of Singly Charged Analytes. Anal. Chem. 1997, 69, 4885–4893.CrossRefGoogle Scholar
  37. 37.
    Shvartsburg, A. A. Acetonitrile Complexes of Triply Charged Metal Ions: Are Ligated Trications Intrinsically More Prone to Charge Reduction than Dications? Chem. Phys. Lett. 2002, 360, 479–486.CrossRefGoogle Scholar
  38. 38.
    Van Berkel, G. J.; Zhou, F.; Aronson, J. T. Changes in Bulk Solution pH Caused by the Inherent Controlled-Current Electrolytic Process of an Electrospray Ion Source. Int. J. Mass Spectrom. Ion. Proc. 1997, 162, 55–67.CrossRefGoogle Scholar

Copyright information

© American Society for Mass Spectrometry 2007

Authors and Affiliations

  • Catarina I. V. Ramos
    • 1
  • M. Graça Santana Marques
    • 1
  • A. J. Ferrer Correia
    • 1
  • Vanda Vaz Serra
    • 2
  • João P. C. Tomé
    • 2
  • Augusto C. Tomé
    • 2
  • M. Graça P. M. S. Neves
    • 2
  • J. A. S. Cavaleiro
    • 2
  1. 1.Mass Spectrometry Laboratory, Department of ChemistryUniversity of AveiroAveiroPortugal
  2. 2.Organic Chemistry Laboratory, Department of ChemistryUniversity of AveiroAveiroPortugal

Personalised recommendations