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Harris RA, May JC, Harvey SR, Wysocki VH, McLean JA. Evaluation of Surface-Induced Dissociation Ion Mobility-Mass Spectrometry for Lipid Structural Characterization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:214-223. [PMID: 38215279 DOI: 10.1021/jasms.3c00319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
Abstract
The complexity of the lipidome has necessitated the development of novel analytical approaches for the identification and structural analysis of morphologically diverse classes of lipids. At this time, a variety of dissociation techniques have been utilized to probe lipid decomposition pathways in search of structurally diagnostic fragment ions. Here, we investigate the application of surface-induced dissociation (SID), a fragmentation technique that imparts energy to the target molecule via collision with a coated surface, for the fragmentation of seven lipids across four major lipid subclasses. We have developed a tuning methodology for guiding the efficient operation of a previously developed custom SID device for molecules as small as ca. 300 Da with ion mobility analysis of the fragmentation products. SID fragmentation of the various lipids analyzed was found to generate fragment ions similar to those observed in CID spectra, but fragment ion lab frame onset energies were lower in SID due to the higher energy deposition via a more massive target. For the largest lipid evaluated (cardiolipin 18:1), SID produced chain fragment ions, which yielded analytically useful information regarding the composition of the acyl tails. Ion mobility provided an orthogonal dimension of separation and aided in assigning product ions to their precursors. Overall, the combination of SID and IM-MS is another potential methodology in the analytical toolkit for lipid structural analysis.
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Affiliation(s)
- Rachel A Harris
- Department of Chemistry, Center for Innovative Technology, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jody C May
- Department of Chemistry, Center for Innovative Technology, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Sophie R Harvey
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - John A McLean
- Department of Chemistry, Center for Innovative Technology, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee 37235, United States
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2
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Karatt TK, Muhammed Ajeebsanu M, Karakka Kal AK, Subhahar MB, Sathiq MA, Laya S. Electrospray ionization mass spectrometry adduct formation by mobile phase additives: A case study using nitrile functional groups containing selective androgen receptor modulators. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9530. [PMID: 37125537 DOI: 10.1002/rcm.9530] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 06/17/2023]
Abstract
RATIONALE The formation of mass adducts is common during electrospray ionization mass spectrometry (ESI-MS). However, the mechanism that leads to adduct formation is poorly understood and difficult to control. Multiplication of mass adducts at once will adversely impact the sensitivity of mass analysis and cause misinterpretation of the level of detection. Prior studies on selective androgen receptor modulators (SARMs) revealed an immense mass adduct formation in both positive and negative ESI modes. METHODS In this study, additives in the mobile phases are investigated as a potential means of controlling mass adduct formation in various SARMs. RESULTS The first evidence of chloride adduct formation when SARMs are detected via ESI-MS has been reported in this research. A series of mobile phase combinations were tested to achieve the optimal condition for HPLC-MS. A comparison was also made between adduct formation on various grades of water used for preparing the mobile phase. A validation study using equine urine and plasma was also conducted to assess the suitability of the developed method. CONCLUSION The results of this study will allow for a more accurate identification of SARMs, which will make it easier to investigate their illicit use in horse racing.
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Affiliation(s)
- Tajudheen Kunhamu Karatt
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates
- Post Graduate and Research Department of Chemistry, Jamal Mohamed College (Affiliated to Bharathidasan University), Tiruchirappalli, India
| | | | | | | | - Mohamedkhani Anwar Sathiq
- Post Graduate and Research Department of Chemistry, Jamal Mohamed College (Affiliated to Bharathidasan University), Tiruchirappalli, India
| | - Saraswathy Laya
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
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3
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Fleissner S, Pittenauer E, Kirchner K. Electrospray Ionization Tandem Mass Spectrometric Study of Selected Phosphine-Based Ligands for Catalytically Active Organometallics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37400456 PMCID: PMC10401707 DOI: 10.1021/jasms.3c00104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Selected organometallic compounds are nowadays extensively used as highly efficient catalysts in organic synthesis. A great variety of different ligand systems exists, of which phosphine-based ligands are a significant subgroup. While mass spectrometry, predominantly electrospray ionization mass spectrometry (ESI-MS), is a standard analytical technique for the identification of new ligands and their metal complexes, there is little information on the behavior of phosphine-based ligands/molecules by electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS/MS) at low collision energies (<100 eV) in the literature. Here, we report a study on the identification of typical product ions occurring in tandem mass spectra of selected phosphine-based ligand systems by ESI-CID-MS/MS. The influence on the fragmentation behavior of different backbones (pyridine, benzene, triazine) as well as different spacer groups (amine, methylamine, methylene), which are directly linked to the phosphine moiety, is investigated by tandem mass spectrometry. In addition, possible fragmentation pathways are elaborated based on the assigned masses in the tandem mass spectra with high-resolution accurate mass determination. This knowledge may be particularly useful in the future for the elucidation of fragmentation pathways for coordination compounds by MS/MS, where the studied compounds serve as building blocks.
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Affiliation(s)
- Sarah Fleissner
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Ernst Pittenauer
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Karl Kirchner
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
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4
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Crotti S, Menicatti M, Pallecchi M, Bartolucci G. Tandem mass spectrometry approaches for recognition of isomeric compounds mixtures. MASS SPECTROMETRY REVIEWS 2023; 42:1244-1260. [PMID: 34841547 DOI: 10.1002/mas.21757] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 06/07/2023]
Abstract
The present review aims to collect the published literature pertaining the recognition of isobaric compounds (isomers or stereoisomers) using the features of tandem mass spectrometry (MS) experiments without any chromatographic separation or chemical modification (derivatization or isotopic enrichment) of the analytes. MS/MS methods possess high selectivity, wide dynamic range and high throughput capabilities. Generally, tandem MS has limited capability for distinguishing isomers that fragment similarly. However, some MS/MS methods have been developed and positively applied to isomers discrimination. Among the literature on this topic, the applications that fit on the review subject can be summarized as follow: (1) chiral discrimination by the kinetic method, (2) the use energy-resolved tandem mass spectra and the survival yield (SY) representation, (3) the kinetics evaluation of the ion-molecule interaction and (4) the postprocessing mathematical algorithm to resolve the isomers in MS/MS signal.
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Affiliation(s)
- Sara Crotti
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Marta Menicatti
- Dipartimento Neurofarba, Università di Firenze, Florence, Italy
| | - Marco Pallecchi
- Dipartimento Neurofarba, Università di Firenze, Florence, Italy
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5
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Biomolecular Profiling by MALDI-TOF Mass Spectrometry in Food and Beverage Analyses. Int J Mol Sci 2022; 23:ijms232113631. [DOI: 10.3390/ijms232113631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/20/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has frequently been applied to the analysis of biomolecules. Its strength resides not only in compound identification but particularly in acquiring molecular profiles providing a high discriminating power. The main advantages include its speed, simplicity, versatility, minimum sample preparation needs, and a relatively high tolerance to salts. Other benefits are represented by the possibility of automation, high throughput, sensitivity, accuracy, and good reproducibility, allowing quantitative studies. This review deals with the prominent use of MALDI-TOF MS profiling in food and beverage analysis ranging from the simple detection of sample constituents to quantifications of marker compounds, quality control, and assessment of product authenticity. This review summarizes relevant discoveries that have been obtained with milk and milk products, edible oils, wine, beer, flour, meat, honey, and other alimentary products. Marker molecules are specified: proteins and peptides for milk, cheeses, flour, meat, wine and beer; triacylglycerols and phospholipids for oils; and low-molecular-weight metabolites for wine, beer and chocolate. Special attention is paid to sample preparation techniques and the combination of spectral profiling and statistical evaluation methods, which is powerful for the differentiation of samples and the sensitive detection of frauds and adulterations.
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6
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Burbano-Cachiguango RA, Abreu-Naranjo R, Caicedo-Vargas CE, Ramírez-Romero CA, Calero-Cárdenas AS, Llumiquinga-Marcillo EM, Ruiz-Urigüen M. Effect of a semi-automated fermentation system on the physical and chemical characteristics of Theobroma cacao L. grown in the northern Ecuadorian Amazon. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2022. [DOI: 10.1007/s11694-022-01620-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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7
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Engel KM, Prabutzki P, Leopold J, Nimptsch A, Lemmnitzer K, Vos DRN, Hopf C, Schiller J. A new update of MALDI-TOF mass spectrometry in lipid research. Prog Lipid Res 2022; 86:101145. [PMID: 34995672 DOI: 10.1016/j.plipres.2021.101145] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/06/2021] [Accepted: 12/29/2021] [Indexed: 01/06/2023]
Abstract
Matrix-assisted laser desorption and ionization (MALDI) mass spectrometry (MS) is an indispensable tool in modern lipid research since it is fast, sensitive, tolerates sample impurities and provides spectra without major analyte fragmentation. We will discuss some methodological aspects, the related ion-forming processes and the MALDI MS characteristics of the different lipid classes (with the focus on glycerophospholipids) and the progress, which was achieved during the last ten years. Particular attention will be given to quantitative aspects of MALDI MS since this is widely considered as the most serious drawback of the method. Although the detailed role of the matrix is not yet completely understood, it will be explicitly shown that the careful choice of the matrix is crucial (besides the careful evaluation of the positive and negative ion mass spectra) in order to be able to detect all lipid classes of interest. Two developments will be highlighted: spatially resolved Imaging MS is nowadays well established and the distribution of lipids in tissues merits increasing interest because lipids are readily detectable and represent ubiquitous compounds. It will also be shown that a combination of MALDI MS with thin-layer chromatography (TLC) enables a fast spatially resolved screening of an entire TLC plate which makes the method competitive with LC/MS.
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Affiliation(s)
- Kathrin M Engel
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany
| | - Patricia Prabutzki
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany
| | - Jenny Leopold
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany
| | - Ariane Nimptsch
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany
| | - Katharina Lemmnitzer
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany
| | - D R Naomi Vos
- Center for Biomedical Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, D-68163 Mannheim, Germany
| | - Carsten Hopf
- Center for Biomedical Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, D-68163 Mannheim, Germany
| | - Jürgen Schiller
- Leipzig University, Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Germany.
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8
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Köfeler HC, Ahrends R, Baker ES, Ekroos K, Han X, Hoffmann N, Holčapek M, Wenk MR, Liebisch G. Recommendations for good practice in MS-based lipidomics. J Lipid Res 2021; 62:100138. [PMID: 34662536 PMCID: PMC8585648 DOI: 10.1016/j.jlr.2021.100138] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 12/17/2022] Open
Abstract
In the last 2 decades, lipidomics has become one of the fastest expanding scientific disciplines in biomedical research. With an increasing number of new research groups to the field, it is even more important to design guidelines for assuring high standards of data quality. The Lipidomics Standards Initiative is a community-based endeavor for the coordination of development of these best practice guidelines in lipidomics and is embedded within the International Lipidomics Society. It is the intention of this review to highlight the most quality-relevant aspects of the lipidomics workflow, including preanalytics, sample preparation, MS, and lipid species identification and quantitation. Furthermore, this review just does not only highlights examples of best practice but also sheds light on strengths, drawbacks, and pitfalls in the lipidomic analysis workflow. While this review is neither designed to be a step-by-step protocol by itself nor dedicated to a specific application of lipidomics, it should nevertheless provide the interested reader with links and original publications to obtain a comprehensive overview concerning the state-of-the-art practices in the field.
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Affiliation(s)
- Harald C Köfeler
- Core Facility Mass Spectrometry, Medical University of Graz, Graz, Austria.
| | - Robert Ahrends
- Department for Analytical Chemistry, University of Vienna, Vienna, Austria
| | - Erin S Baker
- Department of Chemistry, North Carolina State University, Raleigh, NC, USA
| | - Kim Ekroos
- Lipidomics Consulting Ltd., Esbo, Finland
| | - Xianlin Han
- Barshop Inst Longev & Aging Studies, Univ Texas Hlth Sci Ctr San Antonio, San Antonio, TX, USA
| | - Nils Hoffmann
- Center for Biotechnology, Universität Bielefeld, Bielefeld, Germany
| | - Michal Holčapek
- Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic
| | - Markus R Wenk
- Singapore Lipidomics Incubator (SLING), Department of Biochemistry, YLL School of Medicine, National University of Singapore, Singapore, Singapore
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany.
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9
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Lai SH, Chu ML, Lin JL, Chen CH. Development of a focused high-energy macromolecular ion beam. Analyst 2021; 146:2936-2944. [PMID: 33949381 DOI: 10.1039/d0an02478c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we report the development of a focused macromolecular ion beam with kinetic energy of up to 110 keV. The system consists of a quadrupole ion trap (QIT), einzel lens and linear accelerator (LINAC). Based on the combination of matrix-assisted laser desorption ionization (MALDI) and quadrupole ion trapping (QIT), ions were desorbed from the surface and trapped with an ion trap to form biomolecular ion packets. Positive- and negative-pulsed voltages were applied on each end-cap electrode of the QIT to extract the ion packets and form an ion beam that was subsequently focused via an einzel lens and accelerated by stepwise pulsed voltages. The tabletop instrument was designed and successfully demonstrated via measurements of molecular ions of insulin, cytochrome c and bovine serum albumin (BSA) with mass-to-charge ratios (m/z) ranging from ∼5.8 to 66.5 k. This is the first report of both a focused and high-kinetic-energy protein ion beam. In addition, both secondary ions and electrons were observed from the surface by hypervelocity ion beam bombardment. This focused macromolecular ion beam has demonstrated its potential in the study of interactions between large molecular ions with other molecules either in the gas phase or upon a surface.
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Affiliation(s)
- Szu-Hsueh Lai
- Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan. and Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Ming-Lee Chu
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Jung-Lee Lin
- Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan.
| | - Chung-Hsuan Chen
- Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan. and Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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10
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Züllig T, Köfeler HC. HIGH RESOLUTION MASS SPECTROMETRY IN LIPIDOMICS. MASS SPECTROMETRY REVIEWS 2021; 40:162-176. [PMID: 32233039 PMCID: PMC8049033 DOI: 10.1002/mas.21627] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 03/06/2020] [Indexed: 05/04/2023]
Abstract
The boost of research output in lipidomics during the last decade is tightly linked to improved instrumentation in mass spectrometry. Associated with this trend is the shift from low resolution-toward high-resolution lipidomics platforms. This review article summarizes the state of the art in the lipidomics field with a particular focus on the merits of high mass resolution. Following some theoretical considerations on the benefits of high mass resolution in lipidomics, it starts with a historical perspective on lipid analysis by sector instruments and moves further to today's instrumental approaches, including shotgun lipidomics, liquid chromatography-mass spectrometry, matrix-assisted laser desorption ionization-time-of-flight, and imaging lipidomics. Subsequently, several data processing and data analysis software packages are critically evaluated with all their pros and cons. Finally, this article emphasizes the importance and necessity of quality standards as the field evolves from its pioneering phase into a mature and robust omics technology and lists various initiatives for improving the applicability of lipidomics. © 2020 The Authors. Mass Spectrometry Reviews published by John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Thomas Züllig
- Core Facility Mass SpectrometryMedical University of Graz, ZMFGrazAustria
| | - Harald C. Köfeler
- Core Facility Mass SpectrometryMedical University of Graz, ZMFGrazAustria
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11
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Coupling Machine Learning and Lipidomics as a Tool to Investigate Metabolic Dysfunction-Associated Fatty Liver Disease. A General Overview. Biomolecules 2021; 11:biom11030473. [PMID: 33810079 PMCID: PMC8004861 DOI: 10.3390/biom11030473] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/08/2021] [Accepted: 03/18/2021] [Indexed: 12/15/2022] Open
Abstract
Hepatic biopsy is the gold standard for staging nonalcoholic fatty liver disease (NAFLD). Unfortunately, accessing the liver is invasive, requires a multidisciplinary team and is too expensive to be conducted on large segments of the population. NAFLD starts quietly and can progress until liver damage is irreversible. Given this complex situation, the search for noninvasive alternatives is clinically important. A hallmark of NAFLD progression is the dysregulation in lipid metabolism. In this context, recent advances in the area of machine learning have increased the interest in evaluating whether multi-omics data analysis performed on peripheral blood can enhance human interpretation. In the present review, we show how the use of machine learning can identify sets of lipids as predictive biomarkers of NAFLD progression. This approach could potentially help clinicians to improve the diagnosis accuracy and predict the future risk of the disease. While NAFLD has no effective treatment yet, the key to slowing the progression of the disease may lie in predictive robust biomarkers. Hence, to detect this disease as soon as possible, the use of computational science can help us to make a more accurate and reliable diagnosis. We aimed to provide a general overview for all readers interested in implementing these methods.
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12
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Randolph CE, Blanksby SJ, McLuckey SA. Enhancing detection and characterization of lipids using charge manipulation in electrospray ionization-tandem mass spectrometry. Chem Phys Lipids 2020; 232:104970. [PMID: 32890498 PMCID: PMC7606777 DOI: 10.1016/j.chemphyslip.2020.104970] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/25/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022]
Abstract
Heightened awareness regarding the implication of disturbances in lipid metabolism with respect to prevalent human-related pathologies demands analytical techniques that provide unambiguous structural characterization and accurate quantitation of lipids in complex biological samples. The diversity in molecular structures of lipids along with their wide range of concentrations in biological matrices present formidable analytical challenges. Modern mass spectrometry (MS) offers an unprecedented level of analytical power in lipid analysis, as many advancements in the field of lipidomics have been facilitated through novel applications of and developments in electrospray ionization tandem mass spectrometry (ESI-MS/MS). ESI allows for the formation of intact lipid ions with little to no fragmentation and has become widely used in contemporary lipidomics experiments due to its sensitivity, reproducibility, and compatibility with condensed-phase modes of separation, such as liquid chromatography (LC). Owing to variations in lipid functional groups, ESI enables partial chemical separation of the lipidome, yet the preferred ion-type is not always formed, impacting lipid detection, characterization, and quantitation. Moreover, conventional ESI-MS/MS approaches often fail to expose diverse subtle structural features like the sites of unsaturation in fatty acyl constituents or acyl chain regiochemistry along the glycerol backbone, representing a significant challenge for ESI-MS/MS. To overcome these shortcomings, various charge manipulation strategies, including charge-switching, have been developed to transform ion-type and charge state, with aims of increasing sensitivity and selectivity of ESI-MS/MS approaches. Importantly, charge manipulation approaches afford enhanced ionization efficiency, improved mixture analysis performance, and access to informative fragmentation channels. Herein, we present a critical review of the current suite of solution-based and gas-phase strategies for the manipulation of lipid ion charge and type relevant to ESI-MS/MS.
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Affiliation(s)
- Caitlin E Randolph
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott A McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
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13
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Jeck V, Froning M, Tiso T, Blank LM, Hayen H. Double bond localization in unsaturated rhamnolipid precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids by liquid chromatography-mass spectrometry applying online Paternò-Büchi reaction. Anal Bioanal Chem 2020; 412:5601-5613. [PMID: 32627084 PMCID: PMC7413879 DOI: 10.1007/s00216-020-02776-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/09/2020] [Accepted: 06/17/2020] [Indexed: 12/29/2022]
Abstract
Lipids are biomolecules with a broad variety of chemical structures, which renders them essential not only for various biological functions but also interestingly for biotechnological applications. Rhamnolipids are microbial glycolipids with surface-active properties and are widely used biosurfactants. They are composed of one or two L-rhamnoses and up to three hydroxy fatty acids. Their biosynthetic precursors are 3-hydroxy(alkanoyloxy)alkanoic acids (HAAs). The latter are also present in cell supernatants as complex mixtures and are extensively studied for their potential to replace synthetically derived surfactants. The carbon chain lengths of HAAs determine their physical properties, such as their abilities to foam and emulsify, and their critical micelle concentration. Despite growing biotechnological interest, methods for structural elucidation are limited and often rely on hydrolysis and analysis of free hydroxy fatty acids losing the connectivity information. Therefore, a high-performance liquid chromatography-mass spectrometry method was developed for comprehensive structural characterization of intact HAAs. Information is provided on chain length and number of double bonds in each hydroxy fatty acid and their linkage by tandem mass spectrometry (MS/MS). Post-column photochemical derivatization by online Paternὸ-Büchi reaction and MS/MS fragmentation experiments generated diagnostic fragments allowing structural characterization down to the double bond position level. Furthermore, the presented experiments demonstrate a powerful approach for structure elucidation of complex lipids by tailored fragmentation.
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Affiliation(s)
- Viola Jeck
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstraße 30, 48149, Münster, Germany
- Lower Saxony State Office for Consumer Protection and Food Safety - LAVES, Martin-Niemöller-Str. 2, 26133, Oldenburg, Germany
| | - Matti Froning
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstraße 30, 48149, Münster, Germany
| | - Till Tiso
- iAMB - Institute of Applied Microbiology, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, 52074, Aachen, Germany
| | - Lars M Blank
- iAMB - Institute of Applied Microbiology, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, 52074, Aachen, Germany
| | - Heiko Hayen
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstraße 30, 48149, Münster, Germany.
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14
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Fincher JA, Korte AR, Dyer JE, Yadavilli S, Morris NJ, Jones DR, Shanmugam VK, Pirlo RK, Vertes A. Mass spectrometry imaging of triglycerides in biological tissues by laser desorption ionization from silicon nanopost arrays. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4443. [PMID: 31524963 DOI: 10.1002/jms.4443] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/31/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
Mass spectrometry imaging (MSI) is used increasingly to simultaneously detect a broad range of biomolecules while mapping their spatial distributions within biological tissue sections. Matrix-assisted laser desorption ionization (MALDI) is recognized as the method-of-choice for MSI applications due in part to its broad molecular coverage. In spite of the remarkable advantages offered by MALDI, imaging of neutral lipids, such as triglycerides (TGs), from tissue has remained a significant challenge due to ion suppression of TGs by phospholipids, e.g. phosphatidylcholines (PCs). To help overcome this limitation, silicon nanopost array (NAPA) substrates were introduced to selectively ionize TGs from biological tissue sections. This matrix-free laser desorption ionization (LDI) platform was previously shown to provide enhanced ionization of certain lipid classes, such as hexosylceramides (HexCers) and phosphatidylethanolamines (PEs) from mouse brain tissue. In this work, we present NAPA as an MSI platform offering enhanced ionization efficiency for TGs from biological tissues relative to MALDI, allowing it to serve as a complement to MALDI-MSI. Analysis of a standard lipid mixture containing PC(18:1/18:1) and TG(16:0/16:0/16:0) by LDI from NAPA provided an ~49 and ~227-fold higher signal for TG(16:0/16:0/16:0) relative to MALDI, when analyzed without and with the addition of a sodium acetate, respectively. In contrast, MALDI provided an ~757 and ~295-fold higher signal for PC(18:1/18:1) compared with NAPA, without and with additional Na+ . Averaged signal intensities for TGs from MSI of mouse lung and human skin tissues exhibited an ~105 and ~49-fold increase, respectively, with LDI from NAPA compared with MALDI. With respect to PCs, MALDI provided an ~2 and ~19-fold increase in signal intensity for mouse lung and human skin tissues, respectively, when compared with NAPA. The complementary coverage obtained by the two platforms demonstrates the utility of using both techniques to maximize the information obtained from lipid MS or MSI experiments.
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Affiliation(s)
- Jarod A Fincher
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Andrew R Korte
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Jacqueline E Dyer
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
| | - Sridevi Yadavilli
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, 20010, USA
| | | | - Derek R Jones
- Division of Rheumatology, School of Medicine and Health Sciences, The George Washington University, Washington, DC, 20037, USA
| | - Victoria K Shanmugam
- Division of Rheumatology, School of Medicine and Health Sciences, The George Washington University, Washington, DC, 20037, USA
| | - Russel K Pirlo
- Chemistry Division, U.S. Naval Research Laboratory, Washington, DC, 20375, USA
| | - Akos Vertes
- Department of Chemistry, The George Washington University, Washington, DC, 20052, USA
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15
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Quehenberger J, Pittenauer E, Allmaier G, Spadiut O. The influence of the specific growth rate on the lipid composition of Sulfolobus acidocaldarius. Extremophiles 2020; 24:413-420. [PMID: 32200441 PMCID: PMC7174258 DOI: 10.1007/s00792-020-01165-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/09/2020] [Indexed: 12/22/2022]
Abstract
Archaeal lipids are constituted of two isoprenoid chains connected via ether bonds to glycerol in the sn-2, 3 position. Due to these unique properties archaeal lipids are significantly more stable against high temperature, low pH, oxidation and enzymatic degradation than conventional lipids. Additionally, in members of the phylum Crenarchaeota condensation of two (monopolar) archaeal diether lipids to a single (bipolar) tetraether lipid as well as formation of cyclopentane rings in the isoprenoid core strongly reduce permeability of the crenarchaeal membranes. In this work we show that the Crenarchaeum Sulfolobus acidocaldarius changes its lipid composition as reaction to a shift in growth rate caused by nutrient limitation. We thereby identified a novel influencing factor for the lipid composition of S. acidocaldarius and were able to determine the effect of this factor on the lipid composition by using MALDI-MS for the semi-quantification of an archaeal lipidome: a shift in the specific growth rate during a controlled continuous cultivation of S. acidocaldarius from 0.011 to 0.035 h−1 led to a change in the ratio of diether to tetraether lipids from 1:3 to 1:5 and a decrease of the average number of cyclopentane rings from 5.1 to 4.6.
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Affiliation(s)
- Julian Quehenberger
- Research Division Biochemical Engineering, Faculty of Technical Chemistry, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Ernst Pittenauer
- Research Group for Mass Spectrometric Bio and Polymer Analytics, Faculty of Technical Chemistry, Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria
| | - Günter Allmaier
- Research Group for Mass Spectrometric Bio and Polymer Analytics, Faculty of Technical Chemistry, Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria
| | - Oliver Spadiut
- Research Division Biochemical Engineering, Faculty of Technical Chemistry, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.
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16
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Lipidomics from sample preparation to data analysis: a primer. Anal Bioanal Chem 2019; 412:2191-2209. [PMID: 31820027 PMCID: PMC7118050 DOI: 10.1007/s00216-019-02241-y] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/09/2019] [Accepted: 10/25/2019] [Indexed: 12/26/2022]
Abstract
Lipids are amongst the most important organic compounds in living organisms, where they serve as building blocks for cellular membranes as well as energy storage and signaling molecules. Lipidomics is the science of the large-scale determination of individual lipid species, and the underlying analytical technology that is used to identify and quantify the lipidome is generally mass spectrometry (MS). This review article provides an overview of the crucial steps in MS-based lipidomics workflows, including sample preparation, either liquid–liquid or solid-phase extraction, derivatization, chromatography, ion-mobility spectrometry, MS, and data processing by various software packages. The associated concepts are discussed from a technical perspective as well as in terms of their application. Furthermore, this article sheds light on recent advances in the technology used in this field and its current limitations. Particular emphasis is placed on data quality assurance and adequate data reporting; some of the most common pitfalls in lipidomics are discussed, along with how to circumvent them.
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17
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Poad BLJ, Marshall DL, Harazim E, Gupta R, Narreddula VR, Young RSE, Duchoslav E, Campbell JL, Broadbent JA, Cvačka J, Mitchell TW, Blanksby SJ. Combining Charge-Switch Derivatization with Ozone-Induced Dissociation for Fatty Acid Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2135-2143. [PMID: 31347025 DOI: 10.1007/s13361-019-02285-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
The specific positions of carbon-carbon double bond(s) within an unsaturated fatty acid exert a significant effect on the physical and chemical properties of the lipid that ultimately inform its biological function(s). Contemporary liquid chromatography-mass spectrometry (MS) strategies based on electrospray ionization coupled to tandem MS can easily detect fatty acyl lipids but generally cannot reveal those specific site(s) of unsaturation. Herein, we describe a novel and versatile workflow whereby fatty acids are first converted to fixed charge N-(4-aminomethylphenyl)pyridinium (AMPP) derivatives and subsequently subjected to ozone-induced dissociation (OzID) on a modified triple quadrupole mass spectrometer. The AMPP modification enhances the detection of fatty acids introduced by direct infusion. Fragmentation of the derivatized fatty acids also provides diagnostic fragment ions upon collision-induced dissociation that can be targeted in precursor ion scans to subsequently trigger OzID analyses in an automated data-dependent workflow. It is these OzID analyses that provide unambiguous assignment of carbon-carbon double bond locations in the AMPP-derivatized fatty acids. The performance of this analysis pipeline is assessed in profiling the patterns of unsaturation in fatty acids within the complex biological secretion vernix caseosa. This analysis uncovers significant isomeric diversity within the fatty acid pool of this sample, including a number of hitherto unreported double bond positional isomers that hint at the activity of potentially new metabolic pathways.
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Affiliation(s)
- Berwyck L J Poad
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Australia.
| | - David L Marshall
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Australia
| | - Eva Harazim
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Rajesh Gupta
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Australia
| | - Venkateswara R Narreddula
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia
| | - Reuben S E Young
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia
| | | | | | - James A Broadbent
- SCIEX, Concord, ON, Canada
- CSIRO Agriculture and Food, St Lucia, Queensland, 4067, Australia
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Todd W Mitchell
- School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Australia.
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18
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Cetraro N, Cody RB, Yew JY. Carbon-carbon double bond position elucidation in fatty acids using ozone-coupled direct analysis in real time mass spectrometry. Analyst 2019; 144:5848-5855. [PMID: 31482871 DOI: 10.1039/c9an01059a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The carbon-carbon double bond positions of unsaturated fatty acids can have markedly different effects on biological function and also serve as biomarkers of disease pathology, dietary history, and species identity. As such, there is great interest in developing methods for the facile determination of double bond position for natural product chemistry, the pharmaceutical industry, and forensics. We paired ozonolysis with direct analysis in real time mass spectrometry (DART MS) to cleave and rapidly identify carbon-carbon double bond position in fatty acids, fatty alcohols, wax esters, and crude fatty acid extracts. In addition, ozone exposure time and DART ion source temperature were investigated to identify optimal conditions. Our results reveal that brief, offline exposure to ozone-generated aldehyde and carboxylate products that are indicative of carbon-carbon double bond position. The relative abundance of diagnostic fragments quantitatively reflects the ratios of isobaric fatty acid positional isomers in a mixture with a correlation coefficient of 0.99. Lastly, the unsaturation profile generated from unfractionated, fatty acid extracts can be used to differentiate insect species and populations. The ability to rapidly elucidate lipid double bond position by combining ozonolysis with DART MS will be useful for lipid structural elucidation, assessing isobaric purity, and potentially distinguishing between animals fed on different diets or belonging to different ecological populations.
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Affiliation(s)
- Nicolas Cetraro
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, 1993 East West Road, Honolulu, USA 96822.
| | - Robert B Cody
- JEOL USA, Inc., 11 Dearborn Rd, Peabody, MA, USA 01960
| | - Joanne Y Yew
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, 1993 East West Road, Honolulu, USA 96822.
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19
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Dufresne M, Patterson NH, Norris JL, Caprioli RM. Combining Salt Doping and Matrix Sublimation for High Spatial Resolution MALDI Imaging Mass Spectrometry of Neutral Lipids. Anal Chem 2019; 91:12928-12934. [DOI: 10.1021/acs.analchem.9b02974] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Martin Dufresne
- Mass Spectrometry Research Center, Vanderbilt University, 465 21st Ave S #9160, Nashville, Tennessee 37235, United States
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States
| | - Nathan Heath Patterson
- Mass Spectrometry Research Center, Vanderbilt University, 465 21st Ave S #9160, Nashville, Tennessee 37235, United States
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States
| | - Jeremy Lynn Norris
- Mass Spectrometry Research Center, Vanderbilt University, 465 21st Ave S #9160, Nashville, Tennessee 37235, United States
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Station B 351822, Nashville, Tennessee 37235, United States
| | - Richard Micheal Caprioli
- Mass Spectrometry Research Center, Vanderbilt University, 465 21st Ave S #9160, Nashville, Tennessee 37235, United States
- Department of Biochemistry, Vanderbilt University, 607 Light Hall, Nashville, Tennessee 37205, United States
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Station B 351822, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Vanderbilt University, 442 Robinson Research Building, 2220 Pierce Avenue, Nashville, Tennessee 37232, United States
- Department of Medicine, Vanderbilt University, 465 21st Ave S #9160, Nashville, Tennessee 37235, United States
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20
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Yener S, van Valenberg HJF. Characterisation of triacylglycerols from bovine milk fat fractions with MALDI-TOF-MS fragmentation. Talanta 2019; 204:533-541. [PMID: 31357330 DOI: 10.1016/j.talanta.2019.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 02/07/2023]
Abstract
In this study, we used MALDI-TOF-MS to profile and characterise the triacylglycerol (TAG) species of anhydrous bovine milk fat (AMF) and its low melting (olein) and high melting (stearin) fractions obtained by dry fractionation. Silver-ion solid phase extraction (Ag+-SPE) cartridges were utilised to separate the TAGs according to saturation degree. Then, several TAG species were selected and fragmented via post-source decay (PSD) fragmentation. MALDI-TOF-MS TAG profiles and fragmentation patterns were compared to the TAG and fatty acid (FA) compositions obtained by gas chromatography-flame ionization detector (GC-FID). We found that, olein was rich in medium length chain TAG species like CN38:0 and CN40:1, whereas stearin was rich in saturated long chain TAG species from CN42:0 to CN52:0. Separation of the TAGs based on saturation degree allowed successful selection of the TAG parent-ion for fragmentation by eliminating the interferences of TAG species that have the same carbon number but vary in number of double bonds. The TAG fragmentation patterns indicated significant differences between AMF, olein and stearin as a result of the dry fractionation process. Compared to AMF, olein yielded in higher fragments of short-chain saturated and middle-chain unsaturated FAs. Whereas, stearin yielded in saturated and monounsaturated long chain FA fragments. Fragmentation of unsaturated long chain TAGs showed that the TAGs in olein contained more C18:1 and C18:2 than that of AMF and stearin. Stearin on the other hand, contained higher amount of TAG species containing C16:0. These results were in line with the FA compositions obtained from GC-FID and suggest that Ag+-SPE cartridges coupled with MALDI-TOF-MS offer an informative and practical approach to characterise fats and oils with complex TAG composition.
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Affiliation(s)
- Sine Yener
- Dairy Science and Technology Group, Food Quality and Design, Wageningen University, PO Box 17, 6700, AA Wageningen, the Netherlands.
| | - Hein J F van Valenberg
- Dairy Science and Technology Group, Food Quality and Design, Wageningen University, PO Box 17, 6700, AA Wageningen, the Netherlands
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21
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Targeting Modified Lipids during Routine Lipidomics Analysis using HILIC and C30 Reverse Phase Liquid Chromatography coupled to Mass Spectrometry. Sci Rep 2019; 9:5048. [PMID: 30911033 PMCID: PMC6433904 DOI: 10.1038/s41598-019-41556-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 03/07/2019] [Indexed: 12/11/2022] Open
Abstract
Lipids are important biomolecules in all biological systems and serve numerous essential cellular functions. The global analysis of complex lipids is very challenging due to the extreme diversity in lipid structures. Variation in linkages and positions of fatty acyl chain(s) on the lipid backbone, functional group modification, occurrence of the molecular species as isomers or isobars are among some of the greatest challenges to resolve in lipidomics. In this work, we describe a routine analytical approach combining two liquid chromatography platforms: hydrophilic interaction (HILIC) and C30 reversed-phase chromatography (C30RP) coupled to high resolution mass spectrometry (HRMS) as complementary high throughput platforms to analyze complex lipid mixtures. Vascular plants (kale leaves and corn roots), rat brain and soil microbes were used as proxies to evaluate the efficiency of the enhanced approach to resolve traditional, as well as, modified lipids during routine lipidomics analysis. We report for the first time, the observation of a modified class of acylphosphatidylglycerol (acylPG) in corn roots by HILIC, and further resolution of the isomers using C30RP chromatography. We also used this approach to demonstrate the presence of high levels of N-monomethyl phosphatidylethanolamine (MMPE) in soil microbes, as well as to determine the regioisomers of lysophospholipids in kale leaves. Additionally, neutral lipids were demonstrated using C30RP chromatography in positive ion mode to resolve triacylglycerol isomers in rat brain. The work presented here demonstrates how the enhanced approach can more routinely permit novel biomarker discovery, or lipid metabolism in a wide range of biological samples.
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22
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An Organic Chemist's Guide to Electrospray Mass Spectrometric Structure Elucidation. Molecules 2019; 24:molecules24030611. [PMID: 30744143 PMCID: PMC6384780 DOI: 10.3390/molecules24030611] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 12/01/2022] Open
Abstract
Tandem mass spectrometry is an important tool for structure elucidation of natural and synthetic organic products. Fragmentation of odd electron ions (OE+) generated by electron ionization (EI) was extensively studied in the last few decades, however there are only a few systematic reviews available concerning the fragmentation of even-electron ions (EE+/EE−) produced by the currently most common ionization techniques, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). This review summarizes the most important features of tandem mass spectra generated by collision-induced dissociation fragmentation and presents didactic examples for the unexperienced users.
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23
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Cova I, Leta V, Mariani C, Pantoni L, Pomati S. Exploring cocoa properties: is theobromine a cognitive modulator? Psychopharmacology (Berl) 2019; 236:561-572. [PMID: 30706099 DOI: 10.1007/s00213-019-5172-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 01/16/2019] [Indexed: 12/13/2022]
Abstract
Nutritional qualities of cocoa have been acknowledged by several authors; a particular focus has been placed on its high content of flavanols, known for their excellent antioxidant properties and subsequent protective effect on cardio- and cerebrovascular systems as well as for neuromodulatory and neuroprotective actions. Other active components of cocoa are methylxanthines (caffeine and theobromine). Whereas the effects of caffeine are extensively researched, the same is not the case for theobromine; this review summarizes evidence on the effect of theobromine on cognitive functions. Considering animal studies, it can be asserted that acute exposition to theobromine has a reduced and delayed nootropic effect with respect to caffeine, whereas both animal and human studies suggested a potential neuroprotective action of long-term assumption of theobromine through a reduction of Aβ amyloid pathology, which is commonly observed in Alzheimer's disease patients' brains. Hence, the conceivable action of theobromine alone and associated with caffeine or other cocoa constituents on cognitive modulation is yet underexplored and future studies are needed to shed light on this promising molecule.
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Affiliation(s)
- Ilaria Cova
- Center for Research and Treatment on Cognitive Dysfunctions, Neurology Unit, L. Sacco University Hospital, Via G.B. Grassi, 74, I-20157, Milan, Italy.
| | - V Leta
- Center for Research and Treatment on Cognitive Dysfunctions, Neurology Unit, L. Sacco University Hospital, Via G.B. Grassi, 74, I-20157, Milan, Italy.,Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - C Mariani
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - L Pantoni
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - S Pomati
- Center for Research and Treatment on Cognitive Dysfunctions, Neurology Unit, L. Sacco University Hospital, Via G.B. Grassi, 74, I-20157, Milan, Italy
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24
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Leopold J, Popkova Y, Engel KM, Schiller J. Recent Developments of Useful MALDI Matrices for the Mass Spectrometric Characterization of Lipids. Biomolecules 2018; 8:biom8040173. [PMID: 30551655 PMCID: PMC6316665 DOI: 10.3390/biom8040173] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/24/2022] Open
Abstract
Matrix-assisted laser desorption/ionization (MALDI) is one of the most successful “soft” ionization methods in the field of mass spectrometry and enables the analysis of a broad range of molecules, including lipids. Although the details of the ionization process are still unknown, the importance of the matrix is commonly accepted. Both, the development of and the search for useful matrices was, and still is, an empirical process, since properties like vacuum stability, high absorption at the laser wavelength, etc. have to be fulfilled by a compound to become a useful matrix. This review provides a survey of successfully used MALDI matrices for the lipid analyses of complex biological samples. The advantages and drawbacks of the established organic matrix molecules (cinnamic or benzoic acid derivatives), liquid crystalline matrices, and mixtures of common matrices will be discussed. Furthermore, we will deal with nanocrystalline matrices, which are most suitable to analyze small molecules, such as free fatty acids. It will be shown that the analysis of mixtures and the quantitative analysis of small molecules can be easily performed if the matrix is carefully selected. Finally, some basic principles of how useful matrix compounds can be “designed” de novo will be introduced.
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Affiliation(s)
- Jenny Leopold
- Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstr. 16/18, Leipzig University, D-04107 Leipzig, Germany.
| | - Yulia Popkova
- Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstr. 16/18, Leipzig University, D-04107 Leipzig, Germany.
| | - Kathrin M Engel
- Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstr. 16/18, Leipzig University, D-04107 Leipzig, Germany.
| | - Jürgen Schiller
- Faculty of Medicine, Institute for Medical Physics and Biophysics, Härtelstr. 16/18, Leipzig University, D-04107 Leipzig, Germany.
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25
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Hsu FF. Mass spectrometry-based shotgun lipidomics - a critical review from the technical point of view. Anal Bioanal Chem 2018; 410:6387-6409. [PMID: 30094786 PMCID: PMC6195124 DOI: 10.1007/s00216-018-1252-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 11/24/2022]
Abstract
Over the past decade, mass spectrometry (MS)-based "shotgun lipidomics" has emerged as a powerful tool for quantitative and qualitative analysis of the complex lipids in the biological system. The aim of this critical review is to give the interested reader a concise overview of the current state of the technology, focused on lipidomic analysis by mass spectrometry. The pros and cons, and pitfalls associated with each available "shotgun lipidomics" method are discussed; and the new strategies for improving the current methods are described. A list of important papers and reviews that are sufficient rather than comprehensive, covering all the aspects of lipidomics including the workflow, methodology, and fundamentals is also compiled for readers to follow. Graphical abstract ᅟ.
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Affiliation(s)
- Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, 660 S Euclid, St. Louis, MO, 63110, USA.
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26
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Peršurić Ž, Saftić L, Mašek T, Kraljević Pavelić S. Comparison of triacylglycerol analysis by MALDI-TOF/MS, fatty acid analysis by GC-MS and non-selective analysis by NIRS in combination with chemometrics for determination of extra virgin olive oil geographical origin. A case study. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.04.072] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Frankfater C, Jiang X, Hsu FF. Characterization of Long-Chain Fatty Acid as N-(4-Aminomethylphenyl) Pyridinium Derivative by MALDI LIFT-TOF/TOF Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1688-1699. [PMID: 29855891 PMCID: PMC6050100 DOI: 10.1007/s13361-018-1993-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 05/20/2023]
Abstract
Charge remote fragmentation (CRF) elimination of CnH2n+2 residues along the aliphatic tail of long chain fatty acid is hall mark of keV high-energy CID fragmentation process. It is an important fragmentation pathway leading to structural characterization of biomolecules by CID tandem mass spectrometry. In this report, we describe MALDI LIFT TOF-TOF mass spectrometric approach to study a wide variety of fatty acids (FAs), which were derivatized to N-(4-aminomethylphenyl) pyridinium (AMPP) derivative, and desorbed as M+ ions by laser with or without matrix. The high-energy MALDI LIFT TOF-TOF mass spectra of FA-AMPP contain fragment ions mainly deriving from CRF cleavages of CnH2n+2 residues, as expected. These ions together with ions from specific cleavages of the bond(s) involving the functional group within the molecule provide more complete structural identification than those produced by low-energy CID/HCD using a linear ion-trap instrument. However, this LIFT TOF-TOF mass spectrometric approach inherits low sensitivity, a typical feature of high-energy CID tandem mass spectrometry. Because of the lack of unit mass precursor ion selection with sufficient sensitivity of the current LIFT TOF-TOF technology, product ion spectra from same chain length fatty acids with difference in one or two double bonds in a mixture are not distinguishable. Graphical Abstract ᅟ.
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Affiliation(s)
- Cheryl Frankfater
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Washington University School of Medicine, Box 8127, 660 S Euclid, St. Louis, MO, 63110, USA
| | - Xuntian Jiang
- Diabetic Cardiovascular Disease Center, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Washington University School of Medicine, Box 8127, 660 S Euclid, St. Louis, MO, 63110, USA.
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Liang K, Gao H, Gu Y, Yang S, Zhang J, Li J, Wang Y, Wang Y, Li Y. Graphene oxide aggregate-assisted LDI-MS for the direct analysis of triacylglycerol in complex biological samples. Anal Chim Acta 2018; 1035:108-118. [PMID: 30224128 DOI: 10.1016/j.aca.2018.07.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 07/18/2018] [Accepted: 07/22/2018] [Indexed: 12/13/2022]
Abstract
Knowledge of blood triacylglycerol (TAG) species is essential to clarify the physiological functions of individual TAG molecules and also to develop potential biomarkers for related diseases. Commonly, lipid samples prepared by organic liquid-liquid extraction contain complex components, thus cannot be directly characterized by mass spectrometry (MS) and often require an additional purification step. Here, we described a laser desorption ionization - mass spectrometry (LDI-MS) method that utilized aggregated graphene oxide (AGO) as both lipid extractant and MS matrix (AGOLDI-MS), to characterize and quantify plasma TAG species without the use of harmful solvent or complex separation step. We first designed and synthesized the AGO material with a multi-layered sheet structure, which could efficiently break up the structure of lipoproteins, and extract plasma TAGs as solid-phase extraction material. Furthermore, in AGOLDI-MS procedure, the AGO could directly act as matrix and selectively produce the MS signals of TAGs without the interferences of phospholipids, which was hardly achieved by using the routine LDI-MS method based on liquid-liquid extraction and small molecular matrix. We confirmed the suitability of AGOLDI-MS as characterization and quantitative tool for TAG species through studying the analysis performances in TAG standards and real plasma samples. To establish potential utility of our method, we characterized 42 human plasmas from healthy and hyperlipemic donators, indicating that the AGOLDI-MS could not only generate comparable quantitative results of total TAGs to current clinical technology, but also monitor the changes of TAG species between different sample groups. This approach could further characterize the compositions of the fatty acid moieties in even low abundant TAGs by the assistance of tandem MS-MS. This concise, specific, and high-throughput approach will facilitate the rapid and precise characterizations of plasma TAGs, and make the MS approach for TAGs more adaptable for clinical uses.
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Affiliation(s)
- Kai Liang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huanyu Gao
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yajun Gu
- School of Medical Laboratory, Tianjin Medical University, Tianjin, 300070, China
| | - Shaojie Yang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; GuangDong Bio-healtech Advanced Co., Ltd, Foshan City, GuangDong Province, 52800, China
| | | | - Jiejie Li
- Beijing Tian Tan Hospital, Beijing, 100050, China
| | - Yilong Wang
- Beijing Tian Tan Hospital, Beijing, 100050, China
| | - Yongjun Wang
- Beijing Tian Tan Hospital, Beijing, 100050, China
| | - Yan Li
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
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29
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Rapid Characterization of Triacylglycerols in Edible Oils by Matrix-assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(17)61073-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Tzompa-Sosa DA, Meurs PP, van Valenberg HJF. Triacylglycerol Profile of Summer and Winter Bovine Milk Fat and the Feasibility of Triacylglycerol Fragmentation. EUR J LIPID SCI TECH 2018. [DOI: 10.1002/ejlt.201700291] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Daylan A. Tzompa-Sosa
- Dairy Science and Technology Group; Food Quality and Design; Wageningen University; Wageningen 6708WG The Netherlands
| | - Pim P. Meurs
- Dairy Science and Technology Group; Food Quality and Design; Wageningen University; Wageningen 6708WG The Netherlands
| | - Hein J. F. van Valenberg
- Dairy Science and Technology Group; Food Quality and Design; Wageningen University; Wageningen 6708WG The Netherlands
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31
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Theoretical study of charge-remote fragmentation along the reaction coordinate of 1,4-hydrogen elimination in the gas-phase: Energy barrier and mechanism. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.11.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Vu N, Brown J, Giles K, Zhang Q. Ozone-induced dissociation on a traveling wave high-resolution mass spectrometer for determination of double-bond position in lipids. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1415-1423. [PMID: 28590551 PMCID: PMC5560992 DOI: 10.1002/rcm.7920] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/31/2017] [Accepted: 06/03/2017] [Indexed: 05/09/2023]
Abstract
RATIONALE The position of C=C within fatty acyl chains affects the biological function of lipids. Ozone-induced dissociation mass spectrometry (OzID-MS) has great potential in determination of lipid double-bond position, but has generally been implemented on low-resolution ion trap mass spectrometers. In addition, most of the OzID-MS experiments carried out so far were focused on the sodiated adducts of lipids; fragmentation of the most commonly observed protonated ions generated in LC/MS-based lipidomics workflow has been less explored. METHODS Ozone generated in line from an ozone generator was connected to the trap and transfer gas supply line of a Synapt G2 high-resolution mass spectrometer. Protonated ions of different phosphatidylcholines (PC) were generated by electrospray ionization through direct infusion. Different parameters, including traveling wave height and velocity, trap entrance and DC potential, were adjusted to maximize the OzID efficiency. sn-positional isomers and cis/trans isomers of lipids were compared for their reactivity with ozone. RESULTS Traveling wave height and velocity were tuned to prolong the encounter time between lipid ions and ozone, and resulted in improved OzID efficiency, as did increasing trapping region DC and entrance potential. Under optimized settings, at least 1000 times enhancement in OzID efficiency was achieved compared to that under default settings for monounsaturated PC standards. Monounsaturated C=C in the sn-2 PC isomer reacted faster with ozone than the sn-1 isomer. Similarly, the C=C in trans PC reacted faster than in cis PC. CONCLUSIONS This is the first implementation of OzID in the trap and transfer region of a traveling wave enabled high-resolution mass spectrometer. The OzID reaction efficiency is significantly improved by slowing down ions in the trap region for their prolonged interaction with ozone. This will facilitate application of high-resolution OzID-MS in lipidomics.
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Affiliation(s)
- Ngoc Vu
- Department of Chemistry & Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
| | | | | | - Qibin Zhang
- Department of Chemistry & Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, NC 28081, USA
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33
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Hancock SE, Poad BL, Batarseh A, Abbott SK, Mitchell TW. Advances and unresolved challenges in the structural characterization of isomeric lipids. Anal Biochem 2017; 524:45-55. [DOI: 10.1016/j.ab.2016.09.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/11/2016] [Accepted: 09/16/2016] [Indexed: 12/25/2022]
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34
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Jergović AM, Peršurić Ž, Saftić L, Kraljević Pavelić S. Evaluation of MALDI-TOF/MS Technology in Olive Oil Adulteration. J AM OIL CHEM SOC 2017. [DOI: 10.1007/s11746-017-2994-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ana-Marija Jergović
- ; Department of Biotechnology, Centre for High-Throughput Technologies; University of Rijeka; Radmile Matejčić 2 Rijeka 51000 Croatia
| | - Željka Peršurić
- ; Department of Biotechnology, Centre for High-Throughput Technologies; University of Rijeka; Radmile Matejčić 2 Rijeka 51000 Croatia
| | - Lara Saftić
- ; Department of Biotechnology, Centre for High-Throughput Technologies; University of Rijeka; Radmile Matejčić 2 Rijeka 51000 Croatia
| | - Sandra Kraljević Pavelić
- ; Department of Biotechnology, Centre for High-Throughput Technologies; University of Rijeka; Radmile Matejčić 2 Rijeka 51000 Croatia
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35
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Poad BLJ, Green MR, Kirk JM, Tomczyk N, Mitchell TW, Blanksby SJ. High-Pressure Ozone-Induced Dissociation for Lipid Structure Elucidation on Fast Chromatographic Timescales. Anal Chem 2017; 89:4223-4229. [DOI: 10.1021/acs.analchem.7b00268] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Berwyck L. J. Poad
- Central
Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Martin R. Green
- Waters Corporation, Altrincham
Road, Wilmslow, Cheshire SK9 4AX, United Kingdom
| | - Jayne M. Kirk
- Waters Corporation, Altrincham
Road, Wilmslow, Cheshire SK9 4AX, United Kingdom
| | - Nick Tomczyk
- Waters Corporation, Altrincham
Road, Wilmslow, Cheshire SK9 4AX, United Kingdom
| | - Todd W. Mitchell
- School
of Medicine, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Stephen J. Blanksby
- Central
Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
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36
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Badu M, Awudza AMJ. Determination of the triacylglycerol content for the identification and assessment of purity of shea butter fat, peanut oil, and palm kernel oil using maldi-tof/tof mass spectroscopic technique. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2016. [DOI: 10.1080/10942912.2016.1155056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Mercy Badu
- Kwame Nkrumah University of Science and Technology, Chemistry Department, Kumasi, Ghana
| | - A. M. Johannes Awudza
- Kwame Nkrumah University of Science and Technology, Chemistry Department, Kumasi, Ghana
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37
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Dufresne M, Masson JF, Chaurand P. Sodium-Doped Gold-Assisted Laser Desorption Ionization for Enhanced Imaging Mass Spectrometry of Triacylglycerols from Thin Tissue Sections. Anal Chem 2016; 88:6018-25. [PMID: 27145160 DOI: 10.1021/acs.analchem.6b01141] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The deposition of sodium salts followed by a sputtered layer of gold has been demonstrated to be a power combination for the analysis of triacylglycerols (TAGs) from tissue sections by laser desorption ionization (LDI) imaging mass spectrometry (IMS). Various sodium salts were tested for their capability to ionize TAGs and their ability to produce fast drying, small crystals (≤3 μm). The spray deposition of a sodium acetate and carbonate buffer mixture at pH 10.3 on which a 28 ± 3 nm sputtered layer of gold (Au-CBS) is subsequently deposited was found to provide the most effective combination for TAG analysis by high imaging resolution IMS. Under these conditions, a 30-fold increase in TAG signal intensity was observed when compared to matrix-assisted LDI (MALDI) methods using 2,5-dihydrobenzoic acid as matrix. Furthermore, Au-CBS led to an increase in the number of detected TAG species from ∼7 with DHB to more than 25 with the novel method, while few phospholipid signals were observed. These results were derived from the IMS investigation of fresh frozen mouse liver and rabbit adrenal gland tissue sections with a range of higher spatial resolutions between 35 and 10 μm. Au-CBS-LDI MS presents a highly sensitive and specific alternative to MALDI MS for imaging of TAGs from tissue sections. This novel approach has the potential to provide new biological insights on the role of TAGs in both health and disease.
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Affiliation(s)
- Martin Dufresne
- Department of Chemistry, University of Montreal , Montreal, Quebec H3C 3J7, Canada
| | - Jean-François Masson
- Department of Chemistry, University of Montreal , Montreal, Quebec H3C 3J7, Canada.,Centre for Self-Assembled Chemical Structures (CSACS), McGill University , Montreal, Quebec H3A 2K6, Canada
| | - Pierre Chaurand
- Department of Chemistry, University of Montreal , Montreal, Quebec H3C 3J7, Canada
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38
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Peršurić Ž, Osuga J, Galinac Grbac T, Peter-Katalinić J, Kraljević Pavelić S. MALDI-SpiralTOF technology for assessment of triacylglycerols in Croatian olive oils. EUR J LIPID SCI TECH 2016. [DOI: 10.1002/ejlt.201500375] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Željka Peršurić
- Department of Biotechnology; Centre for High-Throughput Technologies; University of Rijeka; Rijeka Croatia
| | - Junichi Osuga
- JEOL SAS; Espace Claude Monet-1; Croissy-sur-Seine France
| | | | - Jasna Peter-Katalinić
- Department of Biotechnology; Centre for High-Throughput Technologies; University of Rijeka; Rijeka Croatia
| | - Sandra Kraljević Pavelić
- Department of Biotechnology; Centre for High-Throughput Technologies; University of Rijeka; Rijeka Croatia
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39
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Belgacem O, Pittenauer E, Openshaw ME, Hart PJ, Bowdler A, Allmaier G. Axial spatial distribution focusing: improving MALDI-TOF/RTOF mass spectrometric performance for high-energy collision-induced dissociation of biomolecules. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:343-51. [PMID: 26754126 PMCID: PMC4699192 DOI: 10.1002/rcm.7458] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 11/08/2015] [Accepted: 11/12/2015] [Indexed: 05/19/2023]
Abstract
RATIONALE For the last two decades, curved field reflectron technology has been used in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometers, assisting in the generation of post-source-decay (PSD) or collision-induced dissociation (CID) without decelerating precursor ions, producing true high-energy CID spectra. The result was the generation of product ion mass spectra with product ions typical of high-energy (10 keV and beyond) collision processes. The disadvantage of this approach was the lack of resolution in CID spectra resulting from the excess laser energy deposition used to generate those MS/MS spectra. The work presented in this study overcomes this limitation and includes comprehensive examples of high-energy and high-resolution CID MALDI-MS/MS spectra of biomolecules. METHODS The devices used in this study are TOF/RTOF instruments equipped with a high-vacuum MALDI ion source. High-resolution and high-energy CID spectra result from the use of axial spatial distribution focusing (ASDF) in combination with curved field reflectron technology. RESULTS A CID spectrum of the P14 R1 peptide exhibits product ion resolution in excess of 10,000 (FWHM) but at the same time yields typical high-energy product ions such as w- and [y-2]-type ion series. High-energy CID spectra of lipids, exemplified by a glycerophospholipid and triglyceride, demonstrate C-C backbone fragmentation elucidating the presence of a hydroxyl group in addition to double-bond positioning. A complex high mannose carbohydrate (Man)8 (GlcNAc)2 was also studied at 20 keV collision energy and revealed further high-energy product ions with very high resolution, allowing unambiguous detection and characterization of cross-ring cleavage-related ions. CONCLUSIONS This is the first comprehensive study using a MALDI-TOF/RTOF instrument equipped with a curved field reflectron and an ASDF device prior to the reflectron. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
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Affiliation(s)
- O Belgacem
- Shimadzu, Kratos AnalyticalTrafford Wharf Road, Manchester, M17 1GP, UK
- *Correspondence to: O. Belgacem, Shimadzu, Kratos Analytical, Trafford Wharf Road, Manchester M17 1GP, UK., E-mail:
| | - E Pittenauer
- Institute of Chemical Technologies and Analytics, Vienna University of TechnologyGetreidemarkt 9/164, 1060, Vienna, Austria
| | - M E Openshaw
- Shimadzu, Kratos AnalyticalTrafford Wharf Road, Manchester, M17 1GP, UK
| | - P J Hart
- Shimadzu, Kratos AnalyticalTrafford Wharf Road, Manchester, M17 1GP, UK
| | - A Bowdler
- Shimadzu, Kratos AnalyticalTrafford Wharf Road, Manchester, M17 1GP, UK
| | - G Allmaier
- Institute of Chemical Technologies and Analytics, Vienna University of TechnologyGetreidemarkt 9/164, 1060, Vienna, Austria
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40
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Marshall DL, Pham HT, Bhujel M, Chin JSR, Yew JY, Mori K, Mitchell TW, Blanksby SJ. Sequential Collision- and Ozone-Induced Dissociation Enables Assignment of Relative Acyl Chain Position in Triacylglycerols. Anal Chem 2016; 88:2685-92. [PMID: 26799085 DOI: 10.1021/acs.analchem.5b04001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Unambiguous identification of isomeric lipids by mass spectrometry represents a significant analytical challenge in contemporary lipidomics. Herein, the combination of collision-induced dissociation (CID) with ozone-induced dissociation (OzID) on an ion-trap mass spectrometer is applied to the identification of triacylglycerol (TG) isomers that vary only by the substitution pattern of fatty acyl (FA) chains esterified to the glycerol backbone. Isolated product ions attributed to loss of a single FA arising from CID of [TG + Na](+) ions react rapidly with ozone within the ion trap. The resulting CID/OzID spectra exhibit abundant ions that unequivocally reveal the relative position of FAs along the backbone. Isomeric TGs containing two or three different FA substituents are readily differentiated by diagnostic ions present in their CID/OzID spectra. Compatibility of this method with chromatographic separations enables the characterization of unusual TGs containing multiple short-chain FAs present in Drosophila.
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Affiliation(s)
- David L Marshall
- Central Analytical Research Facility, Queensland University of Technology , Brisbane, Queensland 4001, Australia
| | - Huong T Pham
- School of Chemistry, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - Mahendra Bhujel
- Central Analytical Research Facility, Queensland University of Technology , Brisbane, Queensland 4001, Australia
| | - Jacqueline S R Chin
- Temasek Life Sciences Laboratory, National University of Singapore , 117604, Singapore.,Department of Biological Sciences, National University of Singapore , 117543, Singapore
| | - Joanne Y Yew
- Temasek Life Sciences Laboratory, National University of Singapore , 117604, Singapore.,Department of Biological Sciences, National University of Singapore , 117543, Singapore
| | - Kenji Mori
- Photosensitive Materials Research Center, Toyo Gosei Company, Ltd., Chiba 270-1609, Japan
| | - Todd W Mitchell
- School of Medicine, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Queensland University of Technology , Brisbane, Queensland 4001, Australia.,School of Chemistry, University of Wollongong , Wollongong, New South Wales 2522, Australia
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41
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Šala M, Lísa M, Campbell JL, Holčapek M. Determination of triacylglycerol regioisomers using differential mobility spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:256-264. [PMID: 27071217 DOI: 10.1002/rcm.7430] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
RATIONALE Triacylglycerols (TG) contain three fatty acyls attached to the glycerol backbone in stereochemically numbered positions sn-1, 2 and 3. Isobaric TG with exchanged fatty acyl chains in positions sn-1/3 vs. sn-2 are referred to as regioisomers and the determination of their regioisomeric ratios is important for nutrition purposes. METHODS Differential mobility spectrometry (DMS) coupled to electrospray ionization mass spectrometry (ESI-MS) is applied for the separation of simple unsaturated TG regioisomers extracted from porcine adipose tissue using their silver-ion molecular adducts. RESULTS Four pairs of TG regioisomers containing combinations of unsaturated and saturated fatty acyl chains are successfully separated using DMS with 1-butanol or 1-propanol as the chemical modifier. Various experimental parameters are carefully optimized, such as the separation and compensation voltages applied to DMS electrodes, the type and flow rate of chemical modifier and the dwell time of analyte ions in the DMS cell. The optimized DMS approach is used for the characterization of TG regioisomers in less than one minute, compared to tens of minutes typical for silver-ion or reversed-phase high-performance liquid chromatography/mass spectrometry approaches. CONCLUSIONS The application of this method for the characterization of TG regioisomers in porcine adipose tissue shows the method suitability for analyses of other animal fats.
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Sala P, Pötz S, Brunner M, Trötzmüller M, Fauland A, Triebl A, Hartler J, Lankmayr E, Köfeler HC. Determination of oxidized phosphatidylcholines by hydrophilic interaction liquid chromatography coupled to Fourier transform mass spectrometry. Int J Mol Sci 2015; 16:8351-63. [PMID: 25874761 PMCID: PMC4425085 DOI: 10.3390/ijms16048351] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/02/2015] [Accepted: 04/08/2015] [Indexed: 01/08/2023] Open
Abstract
A novel liquid chromatography-mass spectrometry (LC-MS) approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI) coupled to hydrophilic interaction liquid chromatography (HILIC) was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID) fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL) prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.
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Affiliation(s)
- Pia Sala
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
- Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9/II, Graz 8010, Austria.
| | - Sandra Pötz
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
- Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9/II, Graz 8010, Austria.
| | - Martina Brunner
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
| | - Martin Trötzmüller
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
| | - Alexander Fauland
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
- Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9/II, Graz 8010, Austria.
| | - Alexander Triebl
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
| | - Jürgen Hartler
- Bioinformatics Group, Institute for Knowledge Discovery, Graz University of Technology, Petersgasse 14, Graz 8010, Austria.
- Omics Center Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
| | - Ernst Lankmayr
- Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9/II, Graz 8010, Austria.
| | - Harald C Köfeler
- Core Facility for Mass Spectrometry, Medical University of Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
- Omics Center Graz, Stiftingtalstrasse 24, Graz 8010, Austria.
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Localization of double bonds in triacylglycerols using high-performance liquid chromatography/atmospheric pressure chemical ionization ion-trap mass spectrometry. Anal Bioanal Chem 2015; 407:5175-88. [PMID: 25701424 DOI: 10.1007/s00216-015-8537-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/28/2015] [Accepted: 02/05/2015] [Indexed: 01/25/2023]
Abstract
A method for localizing double bonds in triacylglycerols using high-performance liquid chromatography-tandem mass spectrometry with atmospheric pressure chemical ionization (APCI) was developed. The technique was based on collision-induced dissociation or pulsed Q collision-induced dissociation of the C3H5N(+•) adducts ([M + 55](+•)) formed in the presence of acetonitrile in the APCI source. The spectra were investigated using a large series of standards obtained from commercial sources and prepared by randomization. The fragmentation spectra made it possible to determine (i) the total number of carbons and double bonds in the molecule, (ii) the number of carbons and double bonds in acyls, (iii) the acyl in the sn-2 position on the glycerol backbone, and (iv) the double-bond positions in acyls. The double-bond positions were determined based on two types of fragments (alpha and omega ions) formed by cleavages of C-C bonds vinylic to the original double bond. The composition of the acyls and their positions on glycerol were established from the masses and intensities of the ions formed by the elimination of fatty acids from the [M + 55](+•) precursor. The method was applied for the analysis of triacylglycerols in olive oil and vernix caseosa.
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44
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Quantitative Analysis of TAG in Oils Using Lithium Cationization and Direct-Infusion ESI Tandem Mass Spectrometry. J AM OIL CHEM SOC 2015. [DOI: 10.1007/s11746-015-2604-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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45
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Pittenauer E, Rehulka P, Winkler W, Allmaier G. Collision-induced dissociation of aminophospholipids (PE, MMPE, DMPE, PS): an apparently known fragmentation process revisited. Anal Bioanal Chem 2015; 407:5079-89. [PMID: 25633216 DOI: 10.1007/s00216-015-8470-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/17/2014] [Accepted: 01/07/2015] [Indexed: 01/19/2023]
Abstract
A new type of low-mass substituted 4-oxazolin product ions of [M + H](+) precursor ions of aminophospholipids (glycerophosphatidylethanolamine, glycerophosphatidyl-N-methylethanolamine, glycerophosphatidyl-N,N-dimethylethanolamine, glycerophosphatidylserine) resulting from high-energy collision-induced dissociation (matrix-assisted laser desorption/ionization time-of-flight/reflectron time-of-flight mass spectrometry) and low-energy collision-induced dissociation (e.g., electrospray ionization quadrupole reflectron time-of-flight mass spectrometry) with accurate mass determination is described; these were previously misidentified as CHO-containing radical cationic product ions. The mechanism for the formation of these ions is proposed to be via rapid loss of water followed by cyclization to an 11-membered-ring transition state for the sn-1 fatty acid substituent and to a ten-membered-ring transition state for the sn-2 fatty acid substituent, and via final loss of monoacylglycerol phosphate, leading to substituted 4-oxazolin product ions. The minimum structural requirement for this interesting skeletal rearrangement fragmentation is an amino group linked to at least one hydrogen atom (i.e., ethanolamine, N-methylethanolamine, serine). Therefore, N,N-dimethylethanolamine derivates do not exhibit this type of fragmentation. The analytical value of these product ions is given by the fact that by post source decay and particularly high-energy collision-induced dissociation achieved via matrix-assisted laser desorption/ionization time-of-flight/reflectron time-of-flight mass spectrometry, the sn-2-related substituted 4-oxazolin product ion is always significantly more abundant than the sn-1-related one, which is quite helpful for detailed structural analysis of complex lipids. All other important product ions found are described in detail (following our previously published glycerophospholipid product ion nomenclature; Pittenauer and Allmaier, Int. J. Mass. Spectrom. 301:90-1012, 2011).
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Affiliation(s)
- Ernst Pittenauer
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, 1060, Vienna, Austria
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Bono L, Seraglia R, Roverso M, Di Carro M, Magi E. Triacylglycerol profile in cocoa liquors using MALDI-TOF and LC-ESI tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2014; 49:894-899. [PMID: 25230186 DOI: 10.1002/jms.3439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 06/27/2014] [Accepted: 07/08/2014] [Indexed: 06/03/2023]
Abstract
Triacylglycerols are responsible for chocolate's peculiar melting behavior: the type and position of fatty acids on the glycerol molecule strongly affect the melting range of cocoa butter. For this reason, the characterization of triglyceride composition in cocoa products is particularly important. In this work, triacylglycerols extracted from cocoa liquor samples were analyzed by matrix-assisted laser desorption/ionization time-of-flight (TOF) and electrospray ionization tandem mass spectrometry (MS/MS) coupled to liquid chromatography. Extracted samples were initially analyzed by direct injection in MS to obtain information on triglyceride molecular weights; relevant MS parameters were optimized, and the possible formation of the adducts [M + Na](+) and [M + NH(4)](+) was studied. Tandem mass experiments (both with triple quadrupole and TOF/TOF) were performed to study the fragmentation pathways (in particular, the loss of palmitic, stearic and oleic acid) and identify the triacylglycerols in cocoa liquors. Some signals of the spectra obtained with both MS techniques could indicate the presence of diacylglycerols in the cocoa extract, but different experimental evidences demonstrated that they were generated by the in-source fragmentation of triglycerides. A nonaqueous reversed-phase chromatographic separation was also developed and used to support the identification of the analytes; nine triacylglycerols were recognized in the cocoa liquor extracts. The three different batches of Ecuador cocoa liquor did not show significant differences in the triacylglycerol profile.
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Affiliation(s)
- Luca Bono
- Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146, Genova, Italy
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Grossert JS, Cubero Herrera L, Ramaley L, Melanson JE. Studying the chemistry of cationized triacylglycerols using electrospray ionization mass spectrometry and density functional theory computations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1421-1440. [PMID: 24867430 DOI: 10.1007/s13361-014-0917-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/01/2014] [Accepted: 04/02/2014] [Indexed: 06/03/2023]
Abstract
Analysis of triacylglycerols (TAGs), found as complex mixtures in living organisms, is typically accomplished using liquid chromatography, often coupled to mass spectrometry. TAGs, weak bases not protonated using electrospray ionization, are usually ionized by adduct formation with a cation, including those present in the solvent (e.g., Na(+)). There are relatively few reports on the binding of TAGs with cations or on the mechanisms by which cationized TAGs fragment. This work examines binding efficiencies, determined by mass spectrometry and computations, for the complexation of TAGs to a range of cations (Na(+), Li(+), K(+), Ag(+), NH4(+)). While most cations bind to oxygen, Ag(+) binding to unsaturation in the acid side chains is significant. The importance of dimer formation, [2TAG + M](+) was demonstrated using several different types of mass spectrometers. From breakdown curves, it became apparent that two or three acid side chains must be attached to glycerol for strong cationization. Possible mechanisms for fragmentation of lithiated TAGs were modeled by computations on tripropionylglycerol. Viable pathways were found for losses of neutral acids and lithium salts of acids from different positions on the glycerol moiety. Novel lactone structures were proposed for the loss of a neutral acid from one position of the glycerol moiety. These were studied further using triple-stage mass spectrometry (MS(3)). These lactones can account for all the major product ions in the MS(3) spectra in both this work and the literature, which should allow for new insights into the challenging analytical methods needed for naturally occurring TAGs.
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Affiliation(s)
- J Stuart Grossert
- National Research Council Canada, Halifax, Nova Scotia, B3H 3Z1, Canada,
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Yan Y, Ubukata M, Cody RB, Holy TE, Gross ML. High-energy collision-induced dissociation by MALDI TOF/TOF causes charge-remote fragmentation of steroid sulfates. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1404-11. [PMID: 24781458 PMCID: PMC4108546 DOI: 10.1007/s13361-014-0901-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/25/2014] [Accepted: 03/25/2014] [Indexed: 05/24/2023]
Abstract
A method for structural elucidation of biomolecules dating to the 1980s utilized high-energy collisions (~10 keV, laboratory frame) that induced charge-remote fragmentations (CRF), a class of fragmentations particularly informative for lipids, steroids, surfactants, and peptides. Unfortunately, the capability for high-energy activation has largely disappeared with the demise of magnetic sector instruments. With the latest designs of tandem time-of-flight mass spectrometers (TOF/TOF), however, this capability is now being restored to coincide with the renewed interest in metabolites and lipids, including steroid-sulfates and other steroid metabolites. For these metabolites, structure determinations are required at concentration levels below that appropriate for NMR. To meet this need, we explored CRF with TOF/TOF mass spectrometry for two groups of steroid sulfates, 3-sulfates and 21-sulfates. We demonstrated that the current generation of MALDI TOF/TOF instruments can generate charge-remote fragmentations for these materials. The resulting collision-induced dissociation (CID) spectra are useful for positional isomer differentiation and very often allow the complete structure determination of the steroid. We also propose a new nomenclature that directly indicates the cleavage sites on the steroid ring with carbon numbers.
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Affiliation(s)
- Yuetian Yan
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA
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Son J, Lee G, Cha S. Direct analysis of triacylglycerols from crude lipid mixtures by gold nanoparticle-assisted laser desorption/ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:891-894. [PMID: 24590365 DOI: 10.1007/s13361-014-0844-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/24/2014] [Accepted: 01/24/2014] [Indexed: 06/03/2023]
Abstract
Triacylglycerols (TAGs), essential energy storage lipids, are easily detected by conventional MALDI MS when occurring on their own. However, their signals are easily overwhelmed by other lipids, mainly phosphatidylcholines (PCs) and, therefore, require purification. In order to profile TAGs from crude lipid mixtures without prefractionation, we investigated alternative matrixes that can suppress phospholipid ion signals and enhance cationization of TAGs. We found that an aqueous solution of citrate-capped gold nanoparticles (AuNPs) with a diameter of 12 nm is a superior matrix for the laser desorption/ionization mass spectrometry (LDI MS) of TAGs in crude lipid mixtures. The AuNP matrix effectively suppressed other lipid signals such as phospholipids and also provided 100 times lower detection limit for TAGs than 2,5-dihydroxybenzoic acid (DHB), the best conventional MALDI matrix for TAGs. The AuNP-assisted LDI MS enabled us to obtain detailed TAG profiles including minor species directly from crude beef lipid extracts without phospholipid interference. In addition, we could detect TAGs at a trace level from a total brain lipid extract.
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Affiliation(s)
- Jeongjin Son
- Department of Chemistry, Hankuk University of Foreign Studies, Yongin, 449-791, Korea
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Recent methodological advances in MALDI mass spectrometry. Anal Bioanal Chem 2014; 406:2261-78. [PMID: 24652146 DOI: 10.1007/s00216-014-7646-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used for characterization of large, thermally labile biomolecules. Advantages of this analytical technique are high sensitivity, robustness, high-throughput capacity, and applicability to a wide range of compound classes. For some years, MALDI-MS has also been increasingly used for mass spectrometric imaging as well as in other areas of clinical research. Recently, several new concepts have been presented that have the potential to further advance the performance characteristics of MALDI. Among these innovations are novel matrices with low proton affinities for particularly efficient protonation of analyte molecules, use of wavelength-tunable lasers to achieve optimum excitation conditions, and use of liquid matrices for improved quantification. Instrumental modifications have also made possible MALDI-MS imaging with cellular resolution as well as an efficient generation of multiply charged MALDI ions by use of heated vacuum interfaces. This article reviews these recent innovations and gives the author's personal outlook of possible future developments.
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