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Li J, Liu R, Hu Z, Fu S, Yu J, Tang K. Racetrack FAIMS for High-Resolution and High-Sensitivity Characterization of Peptide Conformers. Anal Chem 2024. [PMID: 39153009 DOI: 10.1021/acs.analchem.4c02750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2024]
Abstract
A racetrack field asymmetric waveform ion mobility spectrometry (r-FAIMS) device, which consists of both cylindrical FAIMS (c-FAIMS) and planar FAIMS (p-FAIMS) sections with a 1 mm gap width, was developed and applied for high-resolution and high-sensitivity exploration of conformational diversity for peptides. The optimal operating conditions of r-FAIMS were systemically studied, and the performance of the fully optimized r-FAIMS was compared to a previously developed p-FAIMS in detail by using pure nitrogen as the FAIMS carrier gas. Relying on the ion focusing effect in the c-FAIMS section, the intensity of the FAIMS spectrum for doubly charged bradykinin ions acquired by using r-FAIMS is ∼8.5-fold higher than that acquired by using p-FAIMS under the same resolving power/resolution condition, implying about an order of magnitude better sensitivity of r-FAIMS. In addition, the peak separation resolution of r-FAIMS was ∼1.70-fold higher than p-FAIMS under a similar sensitivity condition for doubly charged bradykinin ions. Due to a reduced gap width of the newly designed r-FAIMS (1 mm) as compared to the previously developed p-FAIMS (1.88 mm), r-FAIMS can operate at a much higher separation field with a similar FAIMS dispersion voltage (DV) to gain significantly higher resolving power. For triply charged syntide 2 ions, the resolving power of r-FAIMS can easily exceed 120 at -3.5 kV DV by using pure nitrogen as the FAIMS carrier gas as compared to 44.2 resolving power obtained by using p-FAIMS at -4.0 kV DV. All of the experimental results have confirmed that r-FAIMS can perform structural characterization of biomolecules with both high resolution and high sensitivity.
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Affiliation(s)
- Junhui Li
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P. R. China
| | - Rong Liu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P. R. China
| | - Zhonghan Hu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P. R. China
| | - Shoushuai Fu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, P. R. China
| | - Jiancheng Yu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, P. R. China
| | - Keqi Tang
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo 315211, P. R. China
- Zhenhai Institute of Mass Spectrometry, Ningbo 315211, P. R. China
- School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P. R. China
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Fu S, Wang C, Li J, Yu J, Tang K. Simulation study of a new racetrack FAIMS analyzer to achieve both high-resolution and high-sensitivity. Talanta 2024; 276:126305. [PMID: 38788385 DOI: 10.1016/j.talanta.2024.126305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/09/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
A new racetrack field-asymmetric waveform ion mobility spectrometry (r-FAIMS) analyzer was developed in this study by combining the existing planar FAIMS (p-FAIMS) and cylindrical FAIMS (c-FAIMS). The ion inlet and outlet regions of r-FAIMS were consisted of a half of c-FAIMS, respectively, and these c-FAIMS were further connected by two p-FAIMS to form a racetrack shaped FAIMS. With such FAIMS working electrode configuration, the ions entering the r-FAIMS can be focused and separated in the first c-FAIMS section, be further separated in the p-FAIMS section with high-resolution, be focused and separated again in the final c-FAIMS section and eventually enter the mass spectrometer or other analyzers for analysis. Detailed simulation by using SIMION software with the default FAIMS user program showed that the ion focusing effect in the first c-FAIMS section ensures the ions entering the following p-FAIMS section as a compact ion packet. This effectively decreases the ion loss caused by Coulomb repulsion and thermal diffusion in p-FAIMS section as compared to the ions being introduced into the p-FAIMS gap randomly in the conventional design. As a result, the ion transmission efficiency of r-FAIMS is at least 3.3-fold higher than the single p-FAIMS under the operating conditions used in this study. The ion trajectory simulation results also showed that the resolving power of r-FAIMS is about the sum of the resolving powers for its c-FAIMS and p-FAIMS sections. The resolving power of r-FAIMS is at least 3.6-fold higher than the single c-FAIMS under the operation conditions used in this study. Therefore, the r-FAIMS can realize both high-resolution and high-sensitive ion mobility separation.
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Affiliation(s)
- Shoushuai Fu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, PR China
| | - Chenlu Wang
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China
| | - Junhui Li
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China.
| | - Jiancheng Yu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, PR China
| | - Keqi Tang
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China.
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Kingsley S, Hoover M, Pettit-Bacovin T, Sawyer AR, Chouinard CD. SLIM-Based High-Resolution Ion Mobility Reveals New Structural Insights into Isomeric Vitamin D Metabolites and their Isotopologues. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38709652 DOI: 10.1021/jasms.4c00116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Testing for vitamin D deficiency remains a high-volume clinical assay, much of which is done using mass spectrometry-based methods to alleviate challenges in selectivity associated with immunoassays. Ion mobility-mass spectrometry (IM-MS) has been proposed as a rapid alternative to traditional LC-MS/MS methods, but understanding the structural ensemble that contributes to the ion mobility behavior of this molecular class is critical. Herein we demonstrate the first application of high-resolution Structures for Lossless Ion Manipulations (SLIM) IM separations of several groups of isomeric vitamin D metabolites. Despite previous IM studies of these molecules, the high resolving power of SLIM (Rp ∼ 200) has revealed additional conformations for several of the compounds. The highly similar collision cross sections (CCS), some differing by as little as 0.7%, precluded adequate characterization with low-resolution IM techniques where, in some cases, wider than expected peak widths and/or subtle shoulders may have hinted at their presence. Importantly, these newly resolved peaks often provided a unique mobility that could be used to separate isomers and provides potential for their use in quantification. Lastly, the contribution of isotopic labeling to arrival time distribution for commonly used 13C- and deuterium-labeled internal standards was explored. Minor shifts of ∼0.2-0.3% were observed, and in some instances these shifts were specific to the conformer being measured (i.e., "closed" vs "open"). Accounting for these shifts is important during raw data extraction to ensure reproducible peak area integration, which will be a critical consideration in future quantitative applications.
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Affiliation(s)
- Selena Kingsley
- Clemson University, Department of Chemistry; Clemson, South Carolina 29634, United States
- Lake Superior State University, Department of Chemistry, Sault Sainte Marie, Michigan 49783, United States
| | - Makenna Hoover
- Clemson University, Department of Chemistry; Clemson, South Carolina 29634, United States
| | - Terra Pettit-Bacovin
- Clemson University, Department of Chemistry; Clemson, South Carolina 29634, United States
| | - Anna Rose Sawyer
- Clemson University, Department of Chemistry; Clemson, South Carolina 29634, United States
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Williamson DL, Windsor HM, Nagy G. Isolating the Contributions from Moments of Inertia in Isotopic Shifts Measured by High-Resolution Cyclic Ion Mobility Separations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38654703 DOI: 10.1021/jasms.4c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The unexpected finding that isotopomers (i.e., isotopic isomers) can be separated with high-resolution ion mobility spectrometry-mass spectrometry (IMS-MS) has raised new structural considerations affecting an ion's mobility, namely its center of mass (CoM) and moments of inertia (MoI). Unfortunately, thus far, no studies have attempted to experimentally isolate either CoM or MoI, as they are intrinsically linked by their definitions, where MoI is calculated in relation to CoM. In this study, we designed and synthesized four isotopically labeled tetrapropylammonium (TAA3) ions, each with a unique mass distribution. Three of the synthesized TAA3 ions were labeled symmetrically, thus having identical CoM but differing MoI, which we verified using density functional theory (DFT) calculations. Consequently, we were able to isolate the effect of MoI changes in high-resolution IMS-MS separations. Cyclic ion mobility spectrometry-mass spectrometry (cIMS-MS) separations of the isotopically labeled TAA3 variants revealed isotopic mobility shifts attributable solely to changes in MoI. A 60-m cIMS-MS separation demonstrated that two nominally isobaric TAA3 pseudoisotopomers could be partially resolved, showcasing potential feasibility for isotopomer separations on commercially available IMS-MS platforms. With our previously established collision cross section (CCS) calibration protocol, we also quantified the relationship between MoI and CCS. Our results represent the first demonstration of IMS-MS separations based solely on MoI differences. We believe these findings will contribute important evidence to the growing body of literature on the physical nature of isotopic shifts in IMS-MS separations and work toward more accurate CCS predictions.
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Affiliation(s)
- David L Williamson
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Haisley M Windsor
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Gabe Nagy
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
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5
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Hao J, Feng R, Li J, Gao W, Yu J, Tang K. A high-performance standalone planar FAIMS system for effective detection of chemical warfare agents via TSPSO algorithm. Talanta 2024; 269:125516. [PMID: 38070286 DOI: 10.1016/j.talanta.2023.125516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/28/2023] [Accepted: 12/03/2023] [Indexed: 01/05/2024]
Abstract
A high-performance standalone planar field asymmetric waveform ion mobility spectrometry (p-FAIMS) system with a deconvolution algorithm (two-step particle swarm optimization algorithm, TSPSO) for overlapping peaks was developed to effectively detect chemical warfare agents (CWAs). Four CWA simulants were applied in this study to systemically evaluate the performance of the standalone p-FAIMS system. The experimental results showed that each CWA simulant in the mixture can be positively identified by carefully comparing the compensation voltage (CV) value of each peak in the FAIMS spectra for the mixture to the ones in the spectra acquired by using the same FAIMS system for the pure CWA simulant standards. The FAIMS spectrum of the CWA simulant mixture might consist of multiple overlapping peaks, which would be difficult to accurately determine the CV value for each CWA simulant peak. This problem has been effectively resolved in this study by deconvoluting the overlapping peaks via the TSPSO algorithm. As the effective peak deconvolution via TSPSO requires the degree of overlap between each FAIMS peak to be lower than a specific value, the flow rate of FAIMS carrier gas was decreased to further improve the resolution of the p-FAIMS system. After the accurate deconvolution, the resolution of original FAIMS spectrum can also be enhanced to achieve baseline separation by using TSPSO algorithm to narrow the peak width of each peak. The experimental results in this study demonstrated the possibility of using TSPSO algorithm to achieve high-resolution on a typically low-resolution standalone FAIMS. The concept in this study can potentially be applied to any low-resolution instruments to achieve high-resolution results.
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Affiliation(s)
- Jie Hao
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, PR China
| | - Rong Feng
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China
| | - Junhui Li
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China.
| | - Wenqing Gao
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China
| | - Jiancheng Yu
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, PR China
| | - Keqi Tang
- Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, 315211, PR China; Zhenhai Institute of Mass Spectrometry, Ningbo, 315211, PR China; School of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, PR China.
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Williamson DL, Nagy G. Coupling Isotopic Shifts with Collision Cross-Section Measurements for Carbohydrate Characterization in High-Resolution Ion Mobility Separations. Anal Chem 2023; 95:13992-14000. [PMID: 37683280 PMCID: PMC10538943 DOI: 10.1021/acs.analchem.3c02619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
Herein, we introduce a two-dimensional strategy to better characterize carbohydrate isomers. In a single experiment, we can derive cyclic ion mobility-mass spectrometry (cIMS-MS)-based collision cross-section (CCS) values in conjunction with measuring isotopic shifts through the relative arrival times of light and heavy isotopologues. These isotopic shifts were introduced by permethylating carbohydrates with either light, CH3, or heavy, CD3, labels at every available hydroxyl group to generate a light/heavy pair of isotopologues for every individual species analyzed. We observed that our calculated CCS values, which were exclusively measured for the light isotopologues, were orthogonal to our measured isotopic shifts (i.e., relative arrival time values between heavy and light permethylated isotopologues). Our permethylation-induced isotopic shifts scaled well with increasing molecular weight, up to ∼m/z 1300, expanding the analysis of isotopic shifts to molecules 3-4 times as large as those previously studied. Our presented use of coupling CCS values with the measurement of isotopic shifts in a single cIMS-MS experiment is a proof-of-concept demonstration that our two-dimensional approach can improve the characterization of challenging isomeric carbohydrates. We envision that our presented 2D approach will have broad utility for varying molecular classes as well as being amenable to many forms of derivatization.
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Affiliation(s)
- David L Williamson
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Gabe Nagy
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
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Pathak P, Shvartsburg AA. High-Definition Differential Ion Mobility Spectrometry with Structural Isotopic Shifts for Anionic Compounds. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37319378 DOI: 10.1021/jasms.3c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Differential ion mobility spectrometry (FAIMS) had emerged in the 2000s as a novel tool for postionization separations in conjunction with mass spectrometry (MS). High-definition FAIMS introduced a decade ago has enabled resolution of peptide, lipid, and other molecular isomers with minute structural variations and recently the isotopic shift analyses where the spectral pattern for stable isotopes fingerprints the ion geometry. Those studies, including all isotopic shift analyses, were in the positive mode. Here, we achieve the same high resolution for anions exemplified by phthalic acid isomers. The resolving power and magnitude of isotopic shifts are in line with the metrics for analogous haloaniline cations, establishing high-definition negative-mode FAIMS with structurally specific isotopic shifts. Different shifts (including the new 18O) remain additive and mutually orthogonal, demonstrating the generality of those properties across the elements and charge states. Expanding to common (not halogenated) organic compounds is a key step toward the broad use of FAIMS isotopic shift methodology.
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Affiliation(s)
- Pratima Pathak
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Alexandre A Shvartsburg
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
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Williamson DL, Trimble TK, Nagy G. Hydrogen-Deuterium-Exchange-Based Mass Distribution Shifts in High-Resolution Cyclic Ion Mobility Separations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37098274 DOI: 10.1021/jasms.3c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The mass distribution of ions influences separations in ion mobility spectrometry-mass spectrometry (IMS-MS). Herein, we introduce a method to induce mass distribution shifts for various analytes using hydrogen-deuterium exchange (HDX) immediately prior to ionization using a dual syringe approach. By replacing labile hydrogens on analytes with deuteriums, we were able to differentiate isomers using separations of isotopologues. For each analyte studied, every possible level of deuteration (from undeuterated to fully deuterated) was generated and then separated using cyclic ion mobility spectrometry-mass spectrometry (cIMS-MS). The information gained from such separations (relative arrival times; tRel. values) was found to be orthogonal to conventional IMS-MS separations. Additionally, the observed shifts were linearly additive with increasing deuteration, suggesting that this methodology could be extended to analytes with a larger number of labile hydrogens. For one isomer pair, as few as two deuteriums were able to produce a large enough mass distribution shift to differentiate isomers. In another experiment, we found that the mass distribution shift was large enough to overcome the reduced mass contribution, resulting in a "flipped" arrival time where the heavier deuterated isotopologue arrived before the lighter one. In this work, we present a proof-of-concept demonstration that mass-distribution-based shifts, tRel. values, could potentially act as an added dimension to characterize molecules in IMS-MS. We anticipate, along with future work in this area, that mass-distribution-based shifts could enable the identification of unknown molecules through a database-driven approach in an analogous fashion to collision cross section (CCS) measurements.
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Affiliation(s)
- David L Williamson
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Tyson K Trimble
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Gabe Nagy
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
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Pathak P, Shvartsburg AA. High-Definition Ion Mobility/Mass Spectrometry with Structural Isotopic Shifts for Nominally Isobaric Isotopologues. J Phys Chem A 2023; 127:3914-3923. [PMID: 37083428 DOI: 10.1021/acs.jpca.3c01792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
We had reported the isotopic envelopes in differential IMS (FAIMS) separations depending on the ion structure. However, this new approach to distinguish isomers was constrained by the unit-mass resolution commingling all nominally isobaric isotopologues. Here, we directly couple high-definition FAIMS to ultrahigh-resolution (Orbitrap) MS and employ the resulting platform to explore the FAIMS spectra for isotopic fine structure. The peak shifts therein for isotopologues of halogenated anilines with 15N and 13C (split by 6 mDa) in N2/CO2 buffers dramatically differ, more than for the 13C, 37Cl, or 81Br species apart by 1 or 2 Da. The shifts in FAIMS space upon different elemental isotopic substitutions are orthogonal mutually and to the underlying separations, forming fingerprint multidimensional matrices and 3-D trajectories across gas compositions that redundantly delineate all isomers considered. The interlocking instrumental and methodological upgrades in this work take the structural isotopic shift approach to the next level.
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Affiliation(s)
- Pratima Pathak
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Alexandre A Shvartsburg
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
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Williamson DL, Nagy G. Isomer and Conformer-Specific Mass Distribution-Based Isotopic Shifts in High-Resolution Cyclic Ion Mobility Separations. Anal Chem 2022; 94:12890-12898. [PMID: 36067027 DOI: 10.1021/acs.analchem.2c02991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herein, we present the use of mass distribution-based isotopic shifts in high-resolution cyclic ion mobility spectrometry-mass spectrometry (cIMS-MS)-based separations to characterize various isomeric species as well as conformers. Specifically, by using the observed relative arrival time values for the isotopologues found in the isotopic envelope after long pathlength cIMS-MS separations, we were able to distinguish dibromoaniline, dichloroaniline, and quaternary ammonium salt isomers, as well as a pair of 25-hydroxyvitamin D3 conformers based on their respective mass distribution-based shifts. Our observed shifts were highly reproducible and broadly applied to the isotopologues of various atoms (i.e., Cl, Br, and C). Additionally, through a control experiment, we determined that such shifts are indeed pathlength-independent, thus demonstrating that our presented methodology could be readily extended to other high-resolution IMS-MS platforms. These results are the first characterization of conformers using mass distribution-based IMS-MS shifts, as well as the first use of a commercial cIMS-MS platform to characterize isomers via their mass distribution-based shifts. We anticipate that our methodology will have broad applicability for biological analytes and that mass distribution-based shifts could potentially act as an added dimension of analysis in existing IMS-MS workflows in omics-based research. Specifically, we envision that the development of a database of these mass distribution-based shifts could, for example, enable the identification of unknown metabolites in complex matrices.
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Affiliation(s)
- David L Williamson
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
| | - Gabe Nagy
- Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States
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11
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Lyu L, Sonik N, Bhattacharya S. An overview of lipidomics utilizing cadaver derived biological samples. Expert Rev Proteomics 2021; 18:453-461. [PMID: 34130579 DOI: 10.1080/14789450.2021.1941894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION We present lipidomic studies that have utilized cadaveric biological samples, including tissues and bodily fluids (excluding blood or serum). Analyses of lipids from cadaveric-derived tissues play vital roles in many different fields, such as in anthropogeny to understand food habits of ancient people, in forensics for postmortem analyses, and in biomedical research to study human diseases. AREAS COVERED The goal of the review is to demonstrate how cadavers can be utilized for study of lipidome to get biological insight in different fields. Several important considerations need to be made when analyzing lipids from cadaver samples. For example, what important postmortem changes occur due to environmental or other intrinsic factors that introduce deviations in the observed differences versus true differences? Do these factors affect distinct classes of lipids differently? How do we arrive at a reasonable level of certainty that the observed differences are truly biological rather than artifacts of sample collection, changes during transportation, or variations in analytical procedures? These are pressing questions that need to be addressed when performing lipidomics investigations utilizing postmortem tissues, which inherently presents hurdles and unknowns beginning with harvesting methods, transportation logistics, and at analytical techniques. In our review, we have purposefully omitted blood and serum studies since they pose greater challenges in this regard. Several studies have been carried out with cadaveric tissues and fluids that support the successful use of cases of these samples; however, many control studies are still necessary to provide insight into full potential of the cadaveric tissue and fluid resources. Most importantly, additional control studies will allow us to gain important insights into the opportunities lipidomics presents for biomedical studies of complex human disease and disorders. Another goal of the review is to generate awareness about limitations and pitfalls of use of cadaver materials for study of lipidome. EXPERT OPINION We comment on the current state of lipidomics studies that utilize cadaveric tissues, provide a few pertinent examples, and discuss perspectives on both future technological directions and the applications they will enable.
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Affiliation(s)
- Luheng Lyu
- Miami Integrative Metabolomics Research Center, Bascom Palmer Eye Institute and Department of Ophthalmology, University of Miami, Miami, Florida, USA.,Master's Program in Biomedical Sciences, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida USA
| | - Neel Sonik
- Miami Integrative Metabolomics Research Center, Bascom Palmer Eye Institute and Department of Ophthalmology, University of Miami, Miami, Florida, USA.,Master's Program in Biomedical Sciences, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida USA
| | - Sanjoy Bhattacharya
- Miami Integrative Metabolomics Research Center, Bascom Palmer Eye Institute and Department of Ophthalmology, University of Miami, Miami, Florida, USA.,Master's Program in Biomedical Sciences, Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida USA
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