Different phenylenediamines were used to explore anodic oxidation in solution during electrospray ionization (ESI) mass spectrometry analysis. In our experiments, a series of unknown ionic species was detected in the phenylenediamine solutions. Our results propose that reactions of phenylenediamines with species formed by anodic oxidation of typical ESI solvents during the electrospray ionization process such as formaldehyde are producing these peaks. Identification of these compounds inter alia suggests formal alkylation, a reaction not reported so far as a result of electrolytic oxidation in the prospective organic solvents.
BladesA.T.IkonomouM.G.KebarleP., “Mechanism of electrospray mass spectrometry. electrospray as an electrolysis cell”, Anal. Chem.63, 2109 (1991). doi: 10.1021/ac00019a009
2.
Van BerkelG.J.ZhouF., “Characterization of an electrospray ion source as a controlled-current electrolytic cell”, Anal. Chem.67, 2916 (1995). doi: 10.1021/ac00113a028
3.
Van BerkelG.J.ZhouF.AronsonJ.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.162, 55 (1997). doi: 10.1016/S0168-1176(96)04476-X
4.
MoiniM.CaoP.BardA.J., “Hydroquinone as a buffer additive for suppression of bubbles formed by electrochemical oxidation of the CE buffer at the outlet electrode in capillary electrophoresis/electrospray ionization-mass spectrometry”, Anal. Chem.71, 1658 (1999). doi: 10.1021/ac9811266
5.
Van BerkelG.J.McLuckeyS.A.GlishG.L., “Electrochemical origin of radical cations observed in electrospray ionization mass spectra”, Anal. Chem.64, 1586 (1992). doi: 10.1021/ac00038a015
6.
Van BerkelG.J.ZhouF., “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 (1996). doi: 10.1016/1044-0305(95)00627-3
7.
RohnerT.C.RossierJ.S.GiraultH.H., “On-line electrochemical tagging of cysteines in proteins during nanospray”, Electrochem. Commun.4, 695 (2002). doi: 10.1016/S1388-2481(02)00426-5
8.
ChaiY.SunH.WanJ.PanY.SunC., “Hydride abstraction in positive-ion electrospray interface: Oxidation of 1,4-dihydropyridines in electrospray ionization mass spectrometry”, Analyst136, 4667 (2011). doi: 10.1039/c1an15129k
9.
LositoI.PalmisanoF.ZamboninP.G., “o-Phenylene-diamine electropolymerization by cyclic voltammetry combined with electrospray ionization-ion trap mass spectrometry”, Anal. Chem.75, 4988, (2003). doi: 10.1021/ac0342424
10.
KerteszV.DengH.AsanoK.G.HettichR.L.Van BerkelG.J., “N-phenyl-1,4-phenylenediamine and benzidine oxidation products identified using on-line electrochemistry/electrospray Fourier transform mass spectrometry”, Electroanal.14, 1027 (2002). doi: 10.1002/1521-4109(200208)14:14<1027::AID-ELAN1027>3.0.CO;2-Y
11.
KerteszV.Van BerkelG.J., “Surface-assisted reduction of aniline oligomers, N-phenyl-1,4-phenylenediimine and thionin in atmospheric pressure chemical ionization and atmospheric pressure photoionization”, J. Am. Soc. Mass Spectrom.13, 109 (2002). doi: 10.1016/S1044-0305(01)00337-3
12.
Van BerkelG.J.KerteszV.FordM.J.GrangerM.C., “Efficient analyte oxidation in an electrospray ion source using a porous flow-through electrode emitter”, J. Am. Soc. Mass Spectrom.15, 1755 (2004). doi: 10.1016/j.jasms.2004.08.013
13.
Van BerkelG.J.QuirkeJ.M.E.TiganiR.A.DilleyA.S.CoveyT.R., “Derivatization for electrospray ionization mass spectrometry. 3. Electrochemically ionizable derivatives”, Anal. Chem.70, 1544 (1998). doi: 10.1021/ac971348o
LawrenceN.S.DavisJ.JiangL.JonesT.G.J.DavisS.N.ComptonR.G., “Selective determination of thiols: A novel electroanalytical approach”, Analyst125, 661 (2000). doi: 10.1039/b000985g
16.
Van BerkelG.J.McLuckeyS.A.GlishG.L., “Preforming ions in solution via charge-transfer complexation for analysis by electrospray ionization mass spectrometry”, Anal. Chem.63, 2064 (1991). doi: 10.1021/ac00018a032
PhamM.-C.AdamiF.LacazeP.-C.DoucetJ.-P.DuboisJ.-E., “In-situ investigation of the film growth mechanism using multiple internal reflection Fourier transform infrared spectroscopy (mirftirs) part i. behaviour of iron and platinum electrodes in alkaline methanolic solutions”, J. Electroanal. Chem.201, 413 (1986). doi: 10.1016/0022-0728(86)80066-3
19.
XiaX.H.IwasitaT.GeF.VielstichW., “Structural effects and reactivity in methanol oxidation on polycrystalline and single crystal platinum”, Electrochim. Acta41, 711 (1996). doi: 10.1016/0013-4686(95)00360-6
20.
GauldW.AudierH.FosseyJ.RadomL., “Water-catalyzed interconversion of conventional and distonic radical cations: Methanol and methyleneoxonium”, J. Am. Chem. Soc.118, 6299 (1996). doi: 10.1021/ja960924f
21.
KorzeniewskiC.ChildersC.L., “Formaldehyde yields from methanol electrochemical oxidation on platinum”, J. Phys. Chem. B102, 489 (1998). doi: 10.1021/jp9731157
22.
BagotzkyV.S.VassilyeY.B., “Mechanism of electro-oxidation of methanol on the platinum electrode”, Electrochim. Acta12, 1323 (1967). doi: 10.1016/0013-4686(67)80047-1
23.
KrewerU.Vidakovic-KochT.Rihko-StruckmannL., “Electrochemical oxidation of carbon-containing fuels and their dynamics in low-temperature fuel cells”, Chem. Phys. Chem.12, 2518 (2011). doi: 10.1002/cphc.201100095
24.
SwentonJ.S., “Quinone bis- and monoketals via electrochemical oxidation. versatile intermediates for organic synthesis”, Acc. Chem. Res.16, 74 (1983).doi:10.1021/ar00087a001
25.
EhrmannB.M.HenriksenT.CechN.B., “Relative importance of basicity in the gas phase and in solution for determining selectivity in electrospray ionization mass spectrometry”, J. Am. Soc. Mass Spectrom.19, 719 (2008). doi: 10.1016/j.jasms.2008.01.003
SchäferM.DrayßM.SpringerA.ZachariasP.MeerholzK., “Radical cations in electrospray mass spectrometry: Formation of open-shell species, examination of the fragmentation behaviour in ESI-MSn and reaction mechanism studies by detection of transient radical cations”, Eur. J. Org. Chem.31, 5162 (2007). doi: 10.1002/ejoc.200700199
BruceC.R.NorbergR.E.WeissmanS.I., “Measurement of the rate of an electron exchange reaction by nuclear magnetic resonance spectroscopy”, J. Chem. Phys.24, 473 (1956). doi: 10.1063/1.1742507
30.
Van BerkelG.J.AsanoK.G.SchnierP.D., “Electrochemical processes in a wire-in-a-capillary bulk-loaded, nano-electrospray emitter”, J. Am. Soc. Mass Spectrom.12, 853 (2001). doi: 10.1016/S1044-0305(01)00264-1
31.
GrishawJ., Electrochemical Reactions and Mechanisms on Organic Chemistry.Elsevier Science BV, Amsterdam, The Netherlands (2000).
32.
HamannC.HamnettA.VielstichW., Electrochemistry.Wiley-VCH Verlag GmbH & Co KGaA, Weinheim, Germany, p. 369 (2007).
33.
HofmannH.-J.ScholzM.WeissC., “Berechnungen an p-phenylendiaminen”, J. Prakt. Chem.313, 339 (1971). doi: 10.1002/prac.19713130219
34.
BullockA.T.HowardC.B., “Temperature-dependent hyperfine coupling constants in electron spin resonance”, J. Chem. Soc., Faraday Trans. 271, 1008 (1975). doi: 10.1039/f29757101008
