Oversampling Selective Accumulation Trapped Ion Mobility Spectrometry Coupled to FT-ICR MS: Fundamentals and Applications

Benigni, Paolo; Fernandez-Lima, Francisco

doi:10.1021/acs.analchem.6b01946

Cited by 55 publications

(64 citation statements)

References 88 publications

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“…TIMS’ mode of operation and its advantages over traditional IMS are described in ref 19, 30, 31 . We have shown the use of TIMS for the study of isomerization kinetics of small molecules 32–34 , peptides 35, 36 , and proteins 37–42 , the influence of the collision partner on the molecular structure 43 , and the factors that affect molecular-adduct complex lifetime and stability during TIMS measurements 44 .…”

Section: Introductionmentioning

confidence: 99%

Structures of the kinetically trapped i-motif DNA intermediates

Garabedian

Butcher

Lippens

et al. 2016

Phys. Chem. Chem. Phys.

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In the present work, the conformational dynamics and folding pathways of i-motif DNA were studied in solution and in the gas-phase as a function of the solution pH conditions using circular dichroism (CD), photoacoustic calorimetry analysis (PAC), trapped ion mobility spectrometry - mass spectrometry (TIMS-MS), and molecular dynamics (MD). Solution studies showed at thermodynamic equilibrium the existence of a two-state folding mechanism, whereas during the pH = 7.0 → 4.5 transition a fast and slow phase (ΔHfast+ ΔHslow = 43 ± 7 kcal mol−1) with a volume change associated with the formation of hemiprotonated cytosine base pairs and concomitant collapse of the i-motif oligonucleotide into a compact conformation were observed. TIMS-MS experiments showed that gas-phase, kinetically trapped i-motif DNA intermediates produced by nanoESI are preserved, with relative abundances depending on the solution pH conditions. In particular, a folded i-motif DNA structure was observed in nanoESI-TIMS-MS for low charge states in both positive and negative ion mode (e.g., z = +/− 3 to +/−5) at low pH conditions. As solution pH increases, the cytosine deprotonation leads to the loss of cytosine-cytosine+ (C•CH+) base pairing in the CCC strands and in those conditions we observe partially unfolded i-motif DNA conformations in nanoESI-TIMS-MS for higher charge states (e.g., z = − 6 to −9). Collisional induced activation prior TIMS-MS showed the existence of multiple local free energy minima, associated with the i-motif DNA unfolding at z = −6 charge state. For the first time, candidate gas-phase structures are proposed based on mobility measurements of the i-motif DNA unfolding pathway. Moreover, the inspection of partially unfolded i-motif DNA structures (z = −7 and z = −8 charge states) showed that the presence of inner cations may or may not induce conformational changes in the gas-phase. For example, incorporation of ammonium adducts does not lead to major conformational changes while sodium adducts may lead to the formation of sodium mediated bonds between two negatively charged sides inducing the stabilization towards more compact structures in new local, free energy minima in the gas-phase.

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Section: Introductionmentioning

confidence: 99%

Structures of the kinetically trapped i-motif DNA intermediates

Garabedian

Butcher

Lippens

et al. 2016

Phys. Chem. Chem. Phys.

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“…While different versions of instruments (such as Trapped Ion Mobility Spectrometers(TIMS), 27 ) use electric fields opposite to the flow and have been applied in recent years, the implementation has always been at low pressure and for very high mobilities, which allows the particles to be captured using an RF field when , something that cannot be pursued at room pressure. After Λ = 1 has been reached in TIMS, the ions are then subsequently pushed by lowering the electric field to the critical value that pushes the particles through.…”

Section: Methodsmentioning

confidence: 99%

Modeling of an Inverted Drift Tube for Improved Mobility Analysis of Aerosol Particles

Nahin

Oberreit²,

Fukushima

et al. 2017

Sci Rep

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A new mobility particle analyzer, which has been termed Inverted Drift Tube, has been modeled analytically as well as numerically and proven to be a very capable instrument. The basis for the new design have been the shortcomings of the previous ion mobility spectrometers, in particular (a) diffusional broadening which leads to degradation of instrument resolution and (b) inadequate low and fixed resolution (not mobility dependent) for large sizes. To overcome the diffusional broadening and have a mobility based resolution, the IDT uses two varying controllable opposite forces, a flow of gas with velocity v gas , and a linearly increasing electric field that opposes the movement. A new parameter, the separation ratio Λ = v drift /v gas , is employed to determine the best possible separation for a given set of nanoparticles. Due to the system's need to operate at room pressure, two methods of capturing the ions at the end of the drift tube have been developed, Intermittent Push Flow for a large range of mobilities, and Nearly-Stopping Potential Separation, with very high separation but limited only to a narrow mobility range. A chromatography existing concept of resolving power is used to differentiate between peak resolution in the IDT and acceptable separation between similar mobility sizes.Charged gas phase nanoparticles can be subject to drift and separation by means of electric fields. The charge divided by the friction coefficient of the nanoparticle under such fields is defined as electrical mobility and its accurate reckoning is key to the determination of particle size distribution functions. In Aerosol Science, and when dealing with globular particles, a particle's electrical mobility is linked to its diameter, d p , through the well-known equation 1, 2 :where qe is the net charge on the particle (the product of the integer charge state and the unit electron charge), µ is the dynamic viscosity and λ is the mean free path. C c is the Cunningham's correction factor and is a function of the Knudsen number. Most often, mobility based size distribution functions are measured with differential mobility analyzers (DMA) 3 coupled to Condensation Nucleus Counters CNCs 4 , and operated in series as a scanning mobility particle sizer (SMPS) 5,6 . While the SMPS combination has been incredibly successful, there are several shortcomings to its use which could be improved upon employing different techniques. Because the residence time -length divided by sheath velocity-of transmitted particles in a DMA is fixed and independent of particle size, diffusional broadening leads to degradation of instrument resolution for sub 20 nm particles 7,8 . For particles larger than 20 nm, the resolution, defined as Z/ΔZ, is fixed and with values of approximately <10 for most operating commercial devices. This results in adequate resolution but sometimes insufficient -a 90 nm monodisperse distribution is barely distinguishable from a 100 nm monodisperse distribution assuming a resolution of 6-. Similarly, SMPSs typically require sev...

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“…For example, a recent report of Oversampling Selective Accumulation Trapped Ion Mobility Spectrometry (OSA-TIMS) coupled to FT-ICR MS showed high mobility resolving powers (over 250), high mass accuracy (<1 ppm), and ultrahigh mass resolution (over 1,200,000 at m/z 400) during the analysis of a complex mixture of polyaromatic hydrocarbons (PAH) from coal tar. 106 …”

Section: Introductionmentioning

confidence: 99%

Analysis of Photoirradiated Water Accommodated Fractions of Crude Oils Using Tandem TIMS and FT-ICR MS

Benigni¹,

Sandoval²,

Thompson

et al. 2017

Environ. Sci. Technol.

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For the first time, trapped ion mobility spectrometry (TIMS) in tandem with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is applied to the analysis of the low energy water accommodated fraction (WAF) of a crude oil as a function of the exposure to light. The TIMS-FT-ICR MS analysis provided, in addition to the heteroatom series identification, new insights into the WAF isomeric complexity (e.g., [m/z; chemical formula; collision cross section] datasets) for a better evaluation of the degree of chemical and structural photo-induced transformations. Inspection of the [m/z; chemical formula; collision cross section] datasets shows that the WAF composition changes as a function of the exposure to light in the first 115 hours by initial photo-solubilization of HC components and their photo-oxidation up to O4–5 of mainly high double bond equivalence species (DBE > 9). The addition of high resolution TIMS (resolving power of 90–220) to ultrahigh resolution FT-ICR MS (resolving power over 400k) permitted the identification of a larger number of molecular components in a single analysis (e.g., over 47k using TIM-MS compared to 12k by MS alone), with instances of over 6-fold increase in the number of molecular features per nominal mass due to the WAF isomeric complexity. This work represents a stepping stone towards a better understanding of the WAF components and highlights the need for better experimental and theoretical approaches to characterize the WAF structural diversity.

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Oversampling Selective Accumulation Trapped Ion Mobility Spectrometry Coupled to FT-ICR MS: Fundamentals and Applications

Cited by 55 publications

References 88 publications

Structures of the kinetically trapped i-motif DNA intermediates

Structures of the kinetically trapped i-motif DNA intermediates

Modeling of an Inverted Drift Tube for Improved Mobility Analysis of Aerosol Particles

Analysis of Photoirradiated Water Accommodated Fractions of Crude Oils Using Tandem TIMS and FT-ICR MS

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