Extension of dynamic range in Fourier transform ion cyclotron resonance mass spectrometry via stored waveform inverse Fourier transform excitation

Wang, Tao Chin Lin.; Ricca, Tom L.; Marshall, Alan G.

doi:10.1021/ac00127a009

Cited by 162 publications

(85 citation statements)

References 16 publications

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“…Furthermore, with quadrupole isolation, increasing the resolution in precursor selection goes hand in hand with a decrease in signal intensity, which is not an issue in the 2D FT-ICR experiment [38]. Other isolation methods, such as SWIFT [39,40] or CHEF [39,[41][42][43][44][45], are available for high-resolution isolation windows within the ICR cell. Other ion trapping devices, like linear or quadrupolar ion traps [46], can select ions with a narrow isolation window (1 Da or better) using tailored waveforms.…”

Section: Resultsmentioning

confidence: 99%

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Agthoven

Barrow

Chiron³

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules.

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Section: Resultsmentioning

confidence: 99%

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Agthoven

Barrow

Chiron³

et al. 2015

J. Am. Soc. Mass Spectrom.

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“…Table 1 contains the exact molecular weights (to five significant figures) and calculated rate constants for selected parent and fragment ions (experimental details will be discussed in the next section). For all experiments reported herein, before starting the H/D exchange reactions, the single isotopes ( 12 C all ) of the precursor ions were SWIFT isolated [42]. The SWIFT isolation of a single isotope eliminates peak overlap between the 13 C isotopes of the reactant analyte ion and deuterated product species.…”

Section: Resultsmentioning

confidence: 99%

“…After the ions were trapped inside the ICR cell a variable delay period (Ͻ50 s) was allowed for restoration of base pressure. Once the ions were trapped inside the ICR cell, a combination of "CHIRP" frequency sweep [41] and SWIFT dipolar excitation [42] was used to isolate a specific ion or a set of ions. Before H/D exchange reactions, trapped ions were thermalized by nitrogen collisions.…”

Section: Instrumentationmentioning

confidence: 99%

H/D exchange kinetics: Experimental evidence for formation of different b fragment ion conformers/isomers during the gas-phase peptide sequencing

Fattahi

Zekavat

Solouki

2010

J. Am. Soc. Mass Spectrom.

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“…A pulse of argon was used to facilitate the trapping of the ions in the FTMS cell and also served to vibrationally relax them (29,30). Lithium carbonate (m/z 67) and lithium oxalate (m/z 95) were isolated by using an arbitrary waveform excitation (31) and subsequently fragmented upon energetic collisions with a pulse of argon at a nominal energy of 3.5 eV. In the latter case, the resulting LiCO 2 Ϫ ion (m/z 51) was allowed to react with various reagents as a function of time, or alternatively it was broken apart in a second on-resonance CID step using another pulse of argon and a laboratory energy of Ϸ3.5 eV to afford LiO Ϫ (m/z 23).…”

Section: Methodsmentioning

confidence: 99%

Lithium monoxide anion: A ground-state triplet with the strongest base to date

Tian

Chan

Sullivan

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Lithium monoxide anion (LiO ؊ ) has been generated in the gas phase and is found to be a stronger base than methyl anion (CH 3 ؊ ).This makes LiO ؊ the strongest base currently known, and it will be a challenge to produce a singly charged or multiply charged anion that is more basic. The experimental acidity of lithium hydroxide is ⌬H°a cid ‫؍‬ 425.7 ؎ 6.1 kcal⅐mol ؊1 (1 kcal ‫؍‬ 4.184 kJ) and, when combined with results of high-level computations, leads to our best estimate for the acidity of 426 ؎ 2 kcal⅐mol ؊1 .computations ͉ mass spectrometry ͉ super base T he gas-phase acidities of the hydrogen halides were first reported via the application of a thermodynamic cycle (Eqs. 1-5) in 1942 by Briegleb (1, 2).In subsequent years, the acidities of thousands of compounds have been measured by using a variety of techniques (3), and the acidity scale currently spans a 125 kcal⅐mol Ϫ1 (1 kcal ϭ 4.184 kJ) range from CH 4 (⌬H°a cid ϭ 416.8 Ϯ 0.7 kcal⅐mol Ϫ1 ) (4, 5) to HN(SO 2 C 4 F 9 ) 2 (⌬H°a cid ϭ 291.1 Ϯ 2.2 kcal⅐mol Ϫ1 ) (6) [see supporting information (SI) Text]. Methyl anion is the strongest base currently known, which is a position it has occupied for the past 30 years. This raises the question as to whether a more basic species can be made. In this article, we use sophisticated experimental techniques and state-of-the-art theoretical calculations to show that the lithium monoxide anion (LiO Ϫ ) is in fact more basic than methyl anion, and that it will be a challenge to produce a species that is still more basic. Alkyl groups are polarizable but also are generally electronreleasing and, depending on which influence is larger, can destabilize anions. Kinetic measurements indicate that ethane and the secondary position of propane [(CH 3 ) 2 CH 2 ] are 2-3 kcal⅐mol Ϫ1 less acidic than methane (7), but their conjugate bases have never been observed (8, 9). This is not surprising because the electron affinity of methyl radical is only 1.8 Ϯ 0.7 kcal⅐mol Ϫ1 (4), and CH 3 CH 2 Ϫ and (CH 3 ) 2 CH Ϫ are predicted to be unbound with respect to electron detachment (7). Electronegative substituents stabilize negative ions and increase acidities, as reflected by the first-row hydrides [i.e., HF (most acidic) Ͼ H 2 O Ͼ NH 3 Ͼ CH 4 (least acidic)]. To decrease the acidity of a compound and make a stronger base, one might employ an electropositive substituent such as lithium. However, the conjugate bases of lithiated compounds are difficult to prepare in the gas phase, and almost nothing is known about them because the neutral acids tend to be involatile, moisture sensitive, and pyrophoric.A general method for producing metal-containing anions that overcomes these practical problems was developed by Bachrach, Hare, and Kass (10) and subsequently exploited by . In this approach, metal salts of dicarboxylates are produced by electrospray ionization (ESI) and fragmented via energetic collisions (CID), thereby leading to the sequential expulsion of two molecules of carbon dioxide but retention of the metal ion. For example, the con...

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Extension of dynamic range in Fourier transform ion cyclotron resonance mass spectrometry via stored waveform inverse Fourier transform excitation

Cited by 162 publications

References 16 publications

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

H/D exchange kinetics: Experimental evidence for formation of different b fragment ion conformers/isomers during the gas-phase peptide sequencing

Lithium monoxide anion: A ground-state triplet with the strongest base to date

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