Analytical and Bioanalytical Chemistry

, Volume 403, Issue 2, pp 335–343 | Cite as

Utilizing the inherent electrolysis in a chip-based nanoelectrospray emitter system to facilitate selective ionization and mass spectrometric analysis of metallo alkylporphyrins

  • Gary J. Van BerkelEmail author
  • Vilmos Kertesz
Original Paper


A commercially available chip-based infusion nanoelectrospray ionization system was used to ionize metallo alkylporphyrins for mass spectrometric detection and structure elucidation by mass spectrometry. Different ionic forms of model compounds (nickel (II), vanadyl (II), copper (II), and cobalt (II) octaethylporphyrin) were created by using two different types of conductive pipette tips supplied with the device. These pipette tips provide the conductive contact to solution at which the electrolysis process inherent to electrospray takes places in the device. The original unmodified, bare carbon-impregnated plastic pipette tips were exploited to intentionally electrochemically oxidize (ionize) the porphyrins to form molecular radical cations for detection. Use of modified pipette tips, with a surface coating devised to inhibit analyte mass transport to the surface or slow the kinetics of the analyte electrochemical reactions, was shown to limit the ionic species observed in the mass spectra of these porphyrins largely, but not exclusively, to the protonated molecule. Under the conditions of these experiments, the effective upper potential limit for oxidation with the uncoated pipette tip was 1.1 V or less, and the coated pipette tips effectively prevented the oxidation of analytes with redox potentials greater than about 0.25 V. Product ion spectra of either molecular ionic species could be used to determine the alkyl chain length on the porphyrin macrocycle. The utility of this electrochemical ionization approach for the analysis of naturally occurring samples was demonstrated using nickel geoporphyrin fractions isolated from Gilsonite bitumen. Acquiring neutral loss spectra as a means to improve the specificity of detection in these complex natural samples was also illustrated.


Cross sectional view of the chip-based nanoESI device used for selective ionization of metallo alkylporphyrins


Electrospray Electrochemistry Oxidation Porphyrins Gilsonite 



The authors thank Dr. J. Martin E. Quirke (Florida International University) for the nickel porphyrin fractions isolated from Gilsonite. V.K. acknowledges the support of the Bolyai Janos Research Award from the Hungarian Academy of Sciences. This work was supported by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, United States Department of Energy under Contract DE-AC05-00OR22725 with ORNL, managed and operated by UT-Battelle, LLC.


  1. 1.
    Van Berkel GJ, Kertesz V (2007) Using the electrochemistry of the electrospray ion source. Anal Chem 79:5510–5520CrossRefGoogle Scholar
  2. 2.
    Van Berkel GJ, Kertesz V (2010) Electrospray and MALDI mass spectrometry. In: Cole RB (ed) Electrochemistry of the electrospray ion source. Wiley, New York, pp 75–122Google Scholar
  3. 3.
    Abonnenc M, Qiao LA, Liu BH, Girault HH (2010) Electrochemical aspects of electrospray and laser desorption/ionization for mass spectrometry. Ann Rev Anal Chem 3:231–254CrossRefGoogle Scholar
  4. 4.
    Prudent M, Girault HH (2009) Functional electrospray emitters. Analyst 134:2189–2203CrossRefGoogle Scholar
  5. 5.
    Simons DS, Colby BN, Evans CA Jr (1974) Electrohydrodynamic ionization mass spectrometry—the ionization of liquid glycerol and non-volatile organic solutes. Int J Mass Spectrom Ion Phys 15:291–302CrossRefGoogle Scholar
  6. 6.
    Stimpson BP, Evans CA Jr (1978) Electrohydrodynamic Ionization Mass Spectrometry of Biochemical Materials. Biomed Mass Spectrom 5:52–63CrossRefGoogle Scholar
  7. 7.
    Wang W, Kitova EN, Klassen JS (2003) Influence of solution and gas phase processes on protein-carbohydrate binding affinities determined by nanoelectrospray Fourier transform ion cyclotron resonance mass spectrometry. Anal Chem 75:4945–4955CrossRefGoogle Scholar
  8. 8.
    Corkery LJ, Pang H, Schneider BB, Covey TR, Siu KWM (2005) Automated nanospray using chip-based emitters for the quantitative analysis of pharmaceutical compounds. J Am Soc Mass Spectrom 16:363–369CrossRefGoogle Scholar
  9. 9.
    Van Berkel GJ, McLuckey SA, Glish GL (1992) Electrochemical origin of radical cations observed in electrospray ionization mass spectra. Anal Chem 64:1586–1593CrossRefGoogle Scholar
  10. 10.
    Van Berkel GJ, Zhou F (1995) Electrospray as a controlled-current electrolytic cell: electrochemical ionization of neutral analytes for detection by electrospray-mass spectrometry. Anal Chem 67:3958–3964CrossRefGoogle Scholar
  11. 11.
    Van Berkel GJ, Zhou F (1996) 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 7:157–162CrossRefGoogle Scholar
  12. 12.
    Guaratini T, Vessecchi R, Pinto E, Colepicolo P, Lopes NP (2005) Balance of xanthophylls molecular and protonated molecular ions in electrospray ionization. J Mass Spectrom 40:963–968CrossRefGoogle Scholar
  13. 13.
    Li H, Tyndale ST, Heath DD, Letcher RJ (2005) Determination of carotenoids and all trans-retinol in fish eggs by liquid chromatography-electrospray ionization-tandem mass spectrometry. J Chromatogr 816:49–56CrossRefGoogle Scholar
  14. 14.
    Guaratini T, Vessecchi RL, Lavarda FC, Campos PMBGM, Naal Z, Gates PJ, Lopes NP (2004) New chemical evidence for the ability to generate radical molecular ions of polyenes from ESI and HR-MALDI mass spectrometry. Analyst 129:1223–1226CrossRefGoogle Scholar
  15. 15.
    Maziarz EP III, Wood TD (1998) Gas phase dimerization of dimethylaniline in an external electrospray Fourier transform mass spectrometer. J Mass Spectrom 33:45–54CrossRefGoogle Scholar
  16. 16.
    Van Berkel GJ, Kertesz V (2001) Redox buffering in an electrospray ion source using a copper capillary emitter. J Mass Spectrom 36:1125–1132CrossRefGoogle Scholar
  17. 17.
    Van Berkel GJ, Asano KG, Schnier PD (2001) Electrochemical processes in a wire-in-a-capillary bulk–loaded, nano-electrospray emitter. J Am Soc Mass Spectrom 12:853–862CrossRefGoogle Scholar
  18. 18.
    Rohner TC, Girault HH (2005) Study of peptide on-line complexation with transition-metal ions generated from sacrificial electrodes in thin-chip polymer microsprays. Rapid Commun Mass Spectrom 19:1183–1190CrossRefGoogle Scholar
  19. 19.
    Sierra MA, Gómez-Gallego M, Mancheño MJ, Martínez-Alvarez R, Ramírez-López P, Kayali N, González A (2003) Electrospray mass spectra of group 6 (Fischer) carbenes in the presence of electron donor compounds. J Mass Spectrom 38:151–156CrossRefGoogle Scholar
  20. 20.
    Wulff WD, Korthals KA, Martínez-Álvarez R, Gómez-Gallego M, Fernández I, Sierra MA (2005) Study of the ESI-mass spectrometry ionization mechanism of Fischer carbene complexes. J Org Chem 70:5269–5277CrossRefGoogle Scholar
  21. 21.
    Marjasvaara A, Torvinen M, Vainiotalo P (2004) Laccase-catalyzed mediated oxidation of benzyl alcohol: the role of TEMPO and formation of products including benzonitrile studied by nanoelectrospray ionization fourier transform ion cyclotron resonance mass spectrometry. J Mass Spectrom 39:1139–1146CrossRefGoogle Scholar
  22. 22.
    Van Berkel GJ, Kertesz V (2005) Expanded electrochemical capabilities of the electrospray ion source using porous flow-through electrodes as the upstream ground and emitter high-voltage contact. Anal Chem 77:8041–8049CrossRefGoogle Scholar
  23. 23.
    Rohner TC, Josserand J, Jensen H, Girault HH (2003) Numerical investigation of an electrochemically induced tagging in a nanospray for protein analysis. Anal Chem 75:2065–2074CrossRefGoogle Scholar
  24. 24.
    Dayon L, Roussel C, Girault HH (2006) Probing cysteine reactivity in proteins by mass spectrometric EC-tagging. J Proteome Res 5:793–800CrossRefGoogle Scholar
  25. 25.
    Guaratini T, Vessecchi R, Pinto E, Colepicolo P, Lopes NP (2005) Balance of xanthophylls molecular and protonated molecular ions in electrospray ionization. J Mass Spectrom 40:963–968CrossRefGoogle Scholar
  26. 26.
    Dayon L, Josserand J, Girault HH (2005) Electrochemical multi-tagging of cysteinyl peptides during microspray mass spectrometry: numerical simulation of consecutive reactions in a microchannel. Phys Chem Chem Phys 7:4054–4060CrossRefGoogle Scholar
  27. 27.
    Dayon L, Roussel C, Prudent M, Lion N, Girault HH (2005) On-line counting of cysteine residues in peptides during electrospray ionization by electrogenerated tags and their application to protein identification. Electrophoresis 26:238–247CrossRefGoogle Scholar
  28. 28.
    Roussel C, Dayon L, Jensen H, Girault HH (2004) On-line cysteine modification for protein analysis: new probes for electrochemical tagging nanospray mass spectrometry. J Electroanal Chem 570:187–199CrossRefGoogle Scholar
  29. 29.
    Roussel C, Dayon L, Lion N, Rohner TC, Josserand J, Rossier JS, Jensen H, Girault HH (2004) Generation of mass tags by the inherent electrochemistry of electrospray for protein mass spectrometry. J Am Soc Mass Spectrom 15:1767–1779CrossRefGoogle Scholar
  30. 30.
    Roussel C, Rohner TC, Jensen H, Girault HH (2003) Mechanistic aspects of on-line electrochemical tagging of free L-cysteine residues during electrospray ionization for mass spectrometry in protein analysis. Chemphyschem 4:200–206CrossRefGoogle Scholar
  31. 31.
    Rohner TC, Rossier JS, Girault HH (2002) On-line electrochemical tagging of cysteines in proteins during nanospray. Electrochem Commun 4:695–700CrossRefGoogle Scholar
  32. 32.
  33. 33.
    Sugihara JM, McGee LR (1957) Porphyrins in gilsonite. J Org Chem 22:795–798CrossRefGoogle Scholar
  34. 34.
    Quirke JME, Eglinton G, Maxwell JR (1979) Petroporphyrins. 1. Preliminary characterization of the porphyrins of gilsonite. J Am Chem Soc 101:7693–7697CrossRefGoogle Scholar
  35. 35.
    Quirke JME, Maxwell JR (1980) Characterization of a C32 aetioporphyrin from gilsonite as the bis[porphyrinato-mercury(II) acetato]mercury (II) complex, origin and significance. Tetrahedron 36:3453–3456CrossRefGoogle Scholar
  36. 36.
    Quirke JME, Maxwell JR, Eglinton G (1980) Petroporphyrins IV. Nuclear overhauser enhancement H NMR studies of deoxophylloerythroetio porphyrins from gilsonite. Tetrahedron Lett 21:2987–2990CrossRefGoogle Scholar
  37. 37.
    Eglinton G, Hajibrahim SK, Maxwell JR, Quirke JME (1980) Advances in geochemistry. In: Douglas AG, Maxwell JR (eds) Petroporphyrins: structure elucidation and application of HPLC fingerprinting to geochemical problems. Pergamon Press, Oxford, pp 193–203Google Scholar
  38. 38.
    Van Berkel GJ, Quinoñes MA, Quirke JME (1993) Geoporphyrin analysis using electrospray ionization mass spectrometry. Energy Fuel 7:411–419CrossRefGoogle Scholar
  39. 39.
    Zhang S, Van Pelt CK, Henion JD (2003) Automated chip-based nanoelectrospray-mass spectrometry for rapid identification of proteins separated by two-dimensional gel electrophoresis. Electrophoresis 24:3620–3632CrossRefGoogle Scholar
  40. 40.
    Van Berkel GJ, Feimeng Z (1996) Observation of gas-phase molecular dications formed from neutral organics in solution via the controlled-current electrolysis process inherent to electrospray. J Am Soc Mass Spectrom 7:157–162CrossRefGoogle Scholar
  41. 41.
    Quirke, J. M. E. “Mass spectrometry of porphyrins and metalloporphyrins.” Chapter 54 in: the porphyrin handbook, K.M. Kadish, K. M. Smith, R. Guilard, Eds., volume 7/theoretical and physical characterization. Academic Press, New York, NY, 2000, pp.371-422., last visited, November 11, 2011
  42. 42.
    Van Berkel GJ, Joubert Castro A, Filby RH (1991) Tabulation of exact masses and comparison of isotope patterns expected for geoporphyrin molecular ions in electron ionization mass spectra. Applied Geochem 6:105–117CrossRefGoogle Scholar
  43. 43.
    de Hoffmann E (1996) Tandem mass spectrometry: a primer. J Mass Spectrom 31:129–137CrossRefGoogle Scholar
  44. 44.
    Johnson JV, Britton ED, Yost RA, Quirke JME, Cuesta LL (1986) Tandem mass spectrometry for characterization of high carbon number geoporphyrins. Anal Chem 58:1325–1329CrossRefGoogle Scholar
  45. 45.
    Quirke JME, Cuesta LL, Yost RA, Johnson J, Britton ED (1989) Studies on high carbon number geoporphyrins by tandem mass spectrometry. Org Geochem 14:43–50CrossRefGoogle Scholar

Copyright information

© Springer-Verlag (outside the USA) 2012

Authors and Affiliations

  1. 1.Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National LaboratoryOak RidgeUSA
  2. 2.Physics and Chemistry DepartmentSzechenyi Istvan UniversityGyorHungary

Personalised recommendations