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Bräkling S, Kroll K, Stoermer C, Rohner U, Gonin M, Benter T, Kersten H, Klee S. Parallel Operation of Electron Ionization and Chemical Ionization for GC-MS Using a Single TOF Mass Analyzer. Anal Chem 2022; 94:6057-6064. [PMID: 35388701 DOI: 10.1021/acs.analchem.2c00933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work describes a novel mass spectrometer coupled to gas chromatography (GC-MS) that simultaneously displays the mass spectral information of electron (EI)- and chemical ionization (CI)-generated ion populations for a single chromatographic peak. After GC separation, the eluent is equally split and supplied in parallel to an EI and a novel CI source, both operating continuously. Precise switching of the ion optics provides the exact timing to consecutively extract the respective ion population from both sources and transfer them into a time-of-flight (TOF) mass analyzer. This technique enables the acquisition of complementary information from both ion populations (EI and CI) within a single chromatographic run and with sufficient data points to retain the chromatographic fidelity. The carefully designed GC transfer setup, fast ion optical switching, and synchronized TOF data acquisition system provide an automatic and straightforward spectral alignment of two ion populations. With an eluent split ratio of about 50% between the two ion sources, instrument detection limits of <40 fg on the column (octafluoronaphthalene) for the EI and <2 pg (benzophenone) for the CI source were obtained. The system performance and the additional analytical value for compound identification are demonstrated by means of different common GC standard mixtures and a commercial perfume sample of unknown composition.
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Affiliation(s)
- Steffen Bräkling
- TOFWERK, Thun 3645, Switzerland.,Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, Wuppertal 42119, Germany
| | - Kai Kroll
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, Wuppertal 42119, Germany
| | | | | | | | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, Wuppertal 42119, Germany
| | - Hendrik Kersten
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gauss Str. 20, Wuppertal 42119, Germany
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Hu Q, Chen M, Yan M, Wang P, Lei H, Xue H, Ma Q. Comprehensive analysis of Sini decoction and investigation of acid-base self-assembled complexes using cold spray ionization mass spectrometry. Microchem J 2022. [DOI: 10.1016/j.microc.2021.107008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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3
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Direct analysis of saturated hydrocarbons using glow discharge plasma ionization source for mass spectrometry. Talanta 2019; 204:310-319. [DOI: 10.1016/j.talanta.2019.05.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 11/18/2022]
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4
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Giri A, Coutriade M, Racaud A, Stefanuto PH, Okuda K, Dane J, Cody RB, Focant JF. Compositional elucidation of heavy petroleum base oil by GC × GC-EI/PI/CI/FI-TOFMS. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:148-157. [PMID: 30536759 DOI: 10.1002/jms.4319] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/30/2018] [Accepted: 12/02/2018] [Indexed: 06/09/2023]
Abstract
Comprehensive two-dimensional gas chromatography (GC × GC) coupled to time-of-flight mass spectrometry is a powerful separation tool for complex petroleum product analysis. However, the most commonly used electron ionization (EI) technique often makes the identification of the majority of hydrocarbons impossible due to the exhaustive fragmentation and lack of molecular ion preservation, prompting the need of soft-ionization energies. In this study, three different soft-ionization techniques including photo ionization (PI), chemical ionization (CI), and field ionization (FI) were compared against EI to elucidate their relative capabilities to reveal different base oil hydrocarbon classes. Compared with EI (70 eV), PI (10.8 eV) retained significant molecular ion (M+· ) information for a large number of isomeric species including branched-alkanes and saturated monocyclic hydrocarbons along with unique fragmentation patterns. However, for bicyclic/polycyclic naphthenic and aromatic compounds, EI played upper hand by retaining molecular as well as fragment ions to identify the species, whereas PI exhibited mainly molecular ion signals. On the other hand, CI revealed selectivity towards different base oil groups, particularly for steranes, sulfur-containing thiophenes, and esters, yielding protonated molecular ions (M + H)+ for unsaturated and hydride abstracted ions (M-H+ ) for saturated hydrocarbons. FI, as expected, generated intact molecular ions (M+· ) irrespective to the base oil chemical classes. It allowed elemental composition by TOFMS with a mass resolving power up to 8000 (FWHM) and a mass accuracy of 1 mDa, leading to the calculation of heteroatomic content, double bond equivalency, and carbon number of the compounds. The qualitative and quantitative results presented herein offer a unique perspective into the detailed comparison of different ionization techniques corresponding to several hydrocarbon classes.
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Affiliation(s)
- Anupam Giri
- Analytical GTC-EUR, SABIC, Plasticslaan 1, Bergen op Zoom, 4612CX, The Netherlands
| | - Marion Coutriade
- Centre de Recherche de Solaize, Total Marketing Services, Chemin du Canal-BP 22, Solaize, 69360, France
| | - Amandine Racaud
- Centre de Recherche de Solaize, Total Marketing Services, Chemin du Canal-BP 22, Solaize, 69360, France
| | - Pierre-Hugues Stefanuto
- Department of Chemistry, Organic & Biological Analytical Chemistry Group, University of Liège, Allée du 6 aout, B6c, Liège (Sart Tilman), B-4000, Belgium
| | - Koji Okuda
- JEOL USA, 11 Dearborn Road, Peabody, MA, 01960, USA
| | - John Dane
- JEOL USA, 11 Dearborn Road, Peabody, MA, 01960, USA
| | | | - Jean-François Focant
- Department of Chemistry, Organic & Biological Analytical Chemistry Group, University of Liège, Allée du 6 aout, B6c, Liège (Sart Tilman), B-4000, Belgium
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Alam MS, Harrison RM. Recent advances in the application of 2-dimensional gas chromatography with soft and hard ionisation time-of-flight mass spectrometry in environmental analysis. Chem Sci 2016; 7:3968-3977. [PMID: 30155039 PMCID: PMC6013788 DOI: 10.1039/c6sc00465b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/27/2016] [Indexed: 12/23/2022] Open
Abstract
Two-dimensional gas chromatography has huge power for separating complex mixtures. The principles of the technique are outlined together with an overview of detection methods applicable to GC × GC column effluent with a focus on selectivity. Applications of GC × GC techniques in the analysis of petroleum-related and airborne particulate matter samples are reviewed. Mass spectrometric detection can be used alongside spectral libraries to identify eluted compounds, but in complex petroleum-related and atmospheric samples, when used conventionally at high ionisation energies, may not allow differentiation of structural isomers. Available low energy ionisation methods are reviewed and an example given of the additional structural information which can be extracted by measuring mass spectra at both low and high ionisation energies, hence greatly enhancing the selectivity of the technique.
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Affiliation(s)
- Mohammed S Alam
- School of Geography, Earth and Environmental Sciences , University of Birmingham , Edgbaston , Birmingham B15 2TT , UK .
| | - Roy M Harrison
- School of Geography, Earth and Environmental Sciences , University of Birmingham , Edgbaston , Birmingham B15 2TT , UK .
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Alam MS, Stark C, Harrison RM. Using Variable Ionization Energy Time-of-Flight Mass Spectrometry with Comprehensive GC×GC To Identify Isomeric Species. Anal Chem 2016; 88:4211-20. [DOI: 10.1021/acs.analchem.5b03122] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammed S. Alam
- Division of Environmental
Health and Risk Management School of Geography, Earth and Environmental
Sciences University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Christopher Stark
- Division of Environmental
Health and Risk Management School of Geography, Earth and Environmental
Sciences University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Roy M. Harrison
- Division of Environmental
Health and Risk Management School of Geography, Earth and Environmental
Sciences University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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Simmler C, Kulakowski D, Lankin DC, McAlpine JB, Chen SN, Pauli GF. Holistic Analysis Enhances the Description of Metabolic Complexity in Dietary Natural Products. Adv Nutr 2016; 7:179-89. [PMID: 27180381 PMCID: PMC4717887 DOI: 10.3945/an.115.009928] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the field of food and nutrition, complex natural products (NPs) are typically obtained from cells/tissues of diverse organisms such as plants, mushrooms, and animals. Among them, edible fruits, grains, and vegetables represent most of the human diet. Because of an important dietary dependence, the comprehensive metabolomic analysis of dietary NPs, performed holistically via the assessment of as many metabolites as possible, constitutes a fundamental building block for understanding the human diet. Both mass spectrometry (MS) and nuclear magnetic resonance (NMR) are important complementary analytic techniques, covering a wide range of metabolites at different concentrations. Particularly, 1-dimensional 1H-NMR offers an unbiased overview of all metabolites present in a sample without prior knowledge of its composition, thereby leading to an untargeted analysis. In the past decade, NMR-based metabolomics in plant and food analyses has evolved considerably. The scope of the present review, covering literature of the past 5 y, is to address the relevance of 1H-NMR–based metabolomics in food plant studies, including a comparison with MS-based techniques. Major applications of NMR-based metabolomics for the quality control of dietary NPs and assessment of their nutritional values are presented.
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Affiliation(s)
- Charlotte Simmler
- UIC/NIH Center for Botanical Dietary Supplements Research; and
- Center for Natural Product Technologies, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL
| | | | - David C Lankin
- UIC/NIH Center for Botanical Dietary Supplements Research; and
| | - James B McAlpine
- UIC/NIH Center for Botanical Dietary Supplements Research; and
- Center for Natural Product Technologies, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL
| | - Shao-Nong Chen
- UIC/NIH Center for Botanical Dietary Supplements Research; and
- Center for Natural Product Technologies, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL
| | - Guido F Pauli
- UIC/NIH Center for Botanical Dietary Supplements Research; and
- Center for Natural Product Technologies, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL
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Worton DR, Zhang H, Isaacman-VanWertz G, Chan AWH, Wilson KR, Goldstein AH. Comprehensive Chemical Characterization of Hydrocarbons in NIST Standard Reference Material 2779 Gulf of Mexico Crude Oil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13130-13138. [PMID: 26460682 DOI: 10.1021/acs.est.5b03472] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Comprehensive chemical information is needed to understand the environmental fate and impact of hydrocarbons released during oil spills. However, chemical information remains incomplete because of the limitations of current analytical techniques and the inherent chemical complexity of crude oils. In this work, gas chromatography (GC)-amenable C9-C33 hydrocarbons were comprehensively characterized from the National Institute of Standards and Technology Standard Reference Material (NIST SRM) 2779 Gulf of Mexico crude oil by GC coupled to vacuum ultraviolet photoionization mass spectrometry (GC/VUV-MS), with a mass balance of 68 ± 22%. This technique overcomes one important limitation faced by traditional GC and even comprehensive 2D gas chromatography (GC×GC): the necessity for individual compounds to be chromatographically resolved from one another in order to be characterized. VUV photoionization minimizes fragmentation of the molecular ions, facilitating the characterization of the observed hydrocarbons as a function of molecular weight (carbon number, NC), structure (number of double bond equivalents, NDBE), and mass fraction (mg kg(-1)), which represent important metrics for understanding their fate and environmental impacts. Linear alkanes (8 ± 1%), branched alkanes (11 ± 2%), and cycloalkanes (37 ± 12%) dominated the mass with the largest contribution from cycloalkanes containing one or two rings and one or more alkyl side chains (27 ± 9%). Linearity and good agreement with previous work for a subset of >100 components and for the sum of compound classes provided confidence in our measurements and represents the first independent assessment of our analytical approach and calibration methodology. Another crude oil collected from the Marlin platform (35 km northeast of the Macondo well) was shown to be chemically identical within experimental errors to NIST SRM 2779, demonstrating that Marlin crude is an appropriate surrogate oil for researchers conducting laboratory research into impacts of the DeepWater Horizon disaster.
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Affiliation(s)
- David R Worton
- Aerosol Dynamics, Inc. , Berkeley, California 94710, United States
| | | | | | | | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
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