Mobility shifts when buffer gas temperature increases in ion mobility spectrometry are affected by intramolecular bonds

Fernandez‐Maestre, Roberto; Meza-Morelos, Dairo; Wu, Ching

doi:10.1016/j.ijms.2016.06.012

Cited by 10 publications

(15 citation statements)

References 20 publications

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“…The cleavage and formation of IHBs are fast and continuous processes (less than 1 ns) at room temperature in small molecules due to their low energy . Intramolecular hydrogen bonds, besides size and cluster binding energy, have been used to explain mobility shifts when using different SRs in ESI‐IMS‐QMS . In 2016, it was demonstrated that some ions, such as methionine and diamines, showed relatively small mobility shifts at high temperatures after the introduction of SRs because they form IHBs.…”

Section: Intramolecular Bonds and Mobility Shiftsmentioning

confidence: 99%

“…In 2016, it was demonstrated that some ions, such as methionine and diamines, showed relatively small mobility shifts at high temperatures after the introduction of SRs because they form IHBs. The breaking of IHBs at high temperatures increased the ions' CCSs and led to mobility shifts smaller than those of molecules not forming IHBs . Before, mobility shifts at high temperature had been considered to be affected only by declustering, and the increase in collision frequency and the breaking of IHBs was not considered.…”

Section: Intramolecular Bonds and Mobility Shiftsmentioning

confidence: 99%

“…For compounds that sterically hindered the formation of clusters, temperature affected their reduced mobilities only slightly, or did not at all, when SRs were present because there were no clusters to break. These compounds are atenolol and other diamines due to IHBs, and DTBP and TAA ions due to steric hindrance . Relatively large ions, above 300 amu, might show only small variations in mobility from low to high temperatures when small SRs at low concentrations are used in small drift tubes up to 25 cm, atmospheric pressure and ~10 kV.…”

Section: Clustering and Buffer Gas Temperaturesmentioning

confidence: 99%

“…The ion‐SR noncovalent interaction energies (E I ) may be calculated using E I = E cluster − (E SR + E protonated ion ) and proton affinities subtracting protonated ion energies from molecule energies . Interaction energies of ion‐SR clusters have been calculated using the GAMESS program at the B3LYP/6‐311++G(d,p) level of theory and Gaussian 09 at different levels of theory such as B3LYP, X3LYP/6‐311++(d,p), that accounts for the basis set superposition error, CAMB3LYP/6‐311++G(d,p) . M06‐2X/6‐311++(d,p) and B3LYP‐GD3/6‐311++(d,p) were compared when IHB energies were calculated in dextromethorphan and diphenhydramine to demonstrate IHB effects in their mobilities after introduction of 2‐butanol SR in the buffer gas.…”

Section: Computational Calculations For Ion‐sr Interaction Energiesmentioning

confidence: 99%

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Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Fernandez‐Maestre

2018

J Mass Spectrom

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Ion mobility spectrometry (IMS) is an analytical technique used for fast and sensitive detection of illegal substances in customs and airports, diagnosis of diseases through detection of metabolites in breath, fundamental studies in physics and chemistry, space exploration, and many more applications. Ion mobility spectrometry separates ions in the gas-phase drifting under an electric field according to their size to charge ratio. Ion mobility spectrometry disadvantages are false positives that delay transportation, compromise patient's health and other negative issues when IMS is used for detection. To prevent false positives, IMS measures the ion mobilities in 2 different conditions, in pure buffer gas or when shift reagents (SRs) are introduced in this gas, providing 2 different characteristic properties of the ion and increasing the chances of right identification. Mobility shifts with the introduction of SRs in the buffer gas are due to clustering of analyte ions with SRs. Effective SRs are polar volatile compounds with free electron pairs with a tendency to form clusters with the analyte ion. Formation of clusters is favored by formation of stable analyte ion-SR hydrogen bonds, high analytes' proton affinity, and low steric hindrance in the ion charge while stabilization of ion charge by resonance may disfavor it. Inductive effects and the number of adduction sites also affect cluster formation. The prediction of IMS separations of overlapping peaks is important because it simplifies a trial and error procedure. Doping experiments to simplify IMS spectra by changing the ion-analyte reactions forming the so-called alternative reactant ions are not considered in this review and techniques other than drift tube IMS are marginally covered.

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Section: Intramolecular Bonds and Mobility Shiftsmentioning

confidence: 99%

Section: Intramolecular Bonds and Mobility Shiftsmentioning

confidence: 99%

Section: Clustering and Buffer Gas Temperaturesmentioning

confidence: 99%

Section: Computational Calculations For Ion‐sr Interaction Energiesmentioning

confidence: 99%

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Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Fernandez‐Maestre

2018

J Mass Spectrom

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“…The improved resolution was due to mobility shifts in one of the isomeric forms as a result of conformational changes induced by cation adduct formation. Other common approaches to shift the mobility of ions involve the use of mixed carrier gases, shift reagents (SR) and/or changes in temperature of the buffer gas [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Adduct-ion formation in trapped ion mobility spectrometry as a potential tool for studying molecular structures and conformations

Zietek

Mengerink

Jordens

et al. 2017

Int. J. Ion Mobil. Spec.

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Recent developments in the field of ion mobility spectrometry provide new possibilities to explore and understand gas-phase ion chemistry. In this study, hyphenated trapped ion mobility spectrometry-mass spectrometry (TIMS-MS) was applied to investigate analyte ion mobility as function of adduct ion formation for twelve pharmaceutically relevant molecules, and for tetrahydrocannabinol (THC) and its isomer cannabidiol (CBD). Samples were introduced by direct infusion and ions were generated with positive electrospray ionization (ESI+) observing protonated and sodiated ions. Measurements were performed with and without addition of cesium-, lithium-, silver-and sodium ions to the samples. For the tested compounds, metal adduct ions with the same m/z but with different mobility and collision cross section (CCSs) were observed, indicating different molecular conformations. Formation of analyte dimers was also observed, which could be associated with molecular geometry of the compounds. By optimizing the range and speed of the electric field gradient and ramp, respectively, the separation of THC and CBD was achieved by employing the adduct formation. This study demonstrates that the favorable resolution of TIMS combined with the ability to detect weakly bound counter ions is a valuable means for rapid detection, separation and structural assignment of molecular isomers and analyte conformations.

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Adduct ion formation as a tool for the molecular structure assessment of ten isomers in traveling wave and trapped ion mobility spectrometry

Hadavi

Lange

Jordens

et al. 2019

Rapid Comm Mass Spectrometry

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Rationale The separation of isomeric compounds with major differences in their physiochemical and pharmacokinetic properties is of particular importance in pharmaceutical R&D. However, the structural assessment and separation of these compounds with current analytical techniques and methods are still a challenge. In this study, we describe strategies to separate the various structural and stereo‐isomers. Methods The separation of ten structural and stereo‐isomers was investigated using Trapped and Travelling Wave ion mobility spectrometry (TIMS and TWIMS). Different strategies including adduct ion formation with Na, Li, Ag and Cs as well as fragmentation before and after the ion mobility cell were applied to separate the isomeric compounds. Results All the counter ions (in particular Na) strongly coordinated with the test analytes in all the IMS systems. The highest resolving power was achieved for the sodium and lithium adducts using TIMS‐time‐of‐flight (TOF). However, some separation was attained on a Synapt HDMS system with its unique potential to monitor the ion mobility of the product ions. The elution order of the adduct ions was the same in all instruments, in which, unexpectedly, the para‐substituted isomer of the [M + Na]+ species had the lowest collision cross section followed by the meta‐ and ortho‐isomers. Conclusions The formation of adduct ions could facilitate the separation of structural and even stereo‐isomers by generating different molecular conformations. In addition, fragmenting isomers before or after the ion mobility cell is a valuable strategy to separate and also to assess the structures of adducts and different conformers.

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Mobility shifts when buffer gas temperature increases in ion mobility spectrometry are affected by intramolecular bonds

Cited by 10 publications

References 20 publications

Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Buffer gas additives (modifiers/shift reagents) in ion mobility spectrometry: Applications, predictions of mobility shifts, and influence of interaction energy and structure

Adduct-ion formation in trapped ion mobility spectrometry as a potential tool for studying molecular structures and conformations

Adduct ion formation as a tool for the molecular structure assessment of ten isomers in traveling wave and trapped ion mobility spectrometry

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