کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1195531 | 964386 | 2007 | 8 صفحه PDF | دانلود رایگان |
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/Δm50% = 500,000, in which Δm50% is the mass spectral peak full width at half-maximum peak height) is needed to distinguish various close mass doublets: 13C versus 12CH (4.5 mDa), 13CH versus 12CD (2.9 mDa), and H2 versus D (1.5 mDa).
Journal: Journal of the American Society for Mass Spectrometry - Volume 18, Issue 9, September 2007, Pages 1682–1689