title: Atmospheric pressure photoionization proton transfer for complex organic mixtures investigated by fourier transform ion cyclotron resonance mass spectrometry.
abstract: To further clarify the role of dopant solvent in proton transfer in atmospheric pressure photoionization (APPI), we employ ultrahigh-resolution FT-ICR mass analysis to identify M(+*), [M + H](+), [M - H](-), and [M + D](+) species in toluene or perdeuterotoluene for an equimolar mixture of five pyrrolic and pyridinic nitrogen heterocyclic model compounds, as well as for a complex organic mixture (Canadian Athabasca bitumen middle distillate). In the petroleum sample, the protons in the [M + H](+) species originate primarily from other components of the mixture itself, rather than from the toluene dopant. In contrast to electrospray ionization, in which basic (e.g., pyridinic) species protonate to form [M + H](+) positive ions and acidic (e.g., pyrrolic) species deprotonate to form [M - H](-) negative ions, APPI generates ions from both basic and acidic species in a single positive-ion mass spectrum. Ultrahigh-resolution mass analysis (in this work, m/Deltam(50%) = 500,000, in which Deltam(50%) is the mass spectral peak full width at half-maximum peak height) is needed to distinguish various close mass doublets: (13)C versus (12)CH (4.5 mDa), (13)CH versus (12)CD (2.9 mDa), and H(2) versus D (1.5 mDa).
authors: National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
authors: Jeremiah M
authors: JM
authors: Purcell
authors: Christopher L
authors: CL
authors: Hendrickson
authors: Ryan P
authors: RP
authors: Rodgers
authors: Alan G
authors: AG
authors: Marshall
references: Anal Chem. 2000 Aug 1;72(15):3653-9
references: 10952556
references: J Mass Spectrom. 2003 Oct;38(10):1113-5
references: 14595862
references: J Am Soc Mass Spectrom. 1994 Jul;5(7):605-13
references: 24221962
references: Mass Spectrom Rev. 2003 Sep-Oct;22(5):318-31
references: 12949917
references: Anal Chem. 1984 Dec;56(14 ):2744-8
references: 6524653
references: Anal Chem. 2004 Nov 15;76(22):6797-801
references: 15538806
references: Mass Spectrom Rev. 1998 Jan-Feb;17(1):1-35
references: 9768511
references: Anal Chem. 2006 Aug 15;78(16):5906-12
references: 16906739
references: J Am Soc Mass Spectrom. 1995 Jan;6(1):52-6
references: 24222060
references: Anal Chem. 2003 Jul 1;75(13):3256-62
references: 12964777
references: Anal Chem. 2002 Nov 1;74(21):5470-9
references: 12433075
references: Rapid Commun Mass Spectrom. 1996;10(14):1824-8
references: 8953784
references: Anal Chem. 2001 Oct 1;73(19):4676-81
references: 11605846
references: Anal Chem. 2003 May 1;75(9):2172-6
references: 12720358
references: J Am Soc Mass Spectrom. 2007 Jul;18(7):1265-73
references: 17482835
references: Rapid Commun Mass Spectrom. 2003;17(21):2423-9
references: 14587089
references: Science. 1989 Oct 6;246(4926):64-71
references: 2675315
references: J Chromatogr A. 2003 Jun 6;1000(1-2):549-65
references: 12877188