1
|
Bräkling S, Vetter M, Kurtenbach R, Wiesen P, Campbell SJ, Moncur JH, Klee S. Performance Evaluation of an EI&CI Dual Ionization TOFMS Hyphenated with a Flow Modulated GC×GC System. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 39037387 DOI: 10.1021/jasms.4c00138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
The use and compatibility of a dual-ionization TOFMS operating an EI source and a CI source in parallel using a single TOF mass analyzer with flow modulated two-dimensional GC (GC×GC) is described. Important figures of merit of the mass spectrometer that are required for two-dimensional GC hyphenation such as acquisition speed, ion source response, EI/CI switching, the GC transfer, and data alignment are carefully investigated and addressed. Improved fast switching ion optics allow switching in a 100 Hz frequency between EI and CI spectra sampled from the same GC×GC effluent. The spectra quality also influenced by the preseparation, especially of the EI source, is compared to a standard setup operating a single quadrupole MS coupled to the same GC system. Further, two setups including and excluding an additional flame ionization detector are presented. High increments in CI sensitivities are achieved by utilizing the high pumping efficiencies of the CI stage of the used mass spectrometer. By leading high flow ratios of the GC×GC modulation flows toward the CI source, the intensity can be increased by factors of up to 37 while maintaining the pressure balance of the less robust EI source. Finally, thermal desorption GC×GC-EI&CI-TOFMS analyses of traffic emission samples from a federal highway in Germany are executed with the presented setup.
Collapse
Affiliation(s)
| | | | - Ralf Kurtenbach
- Physical & Theoretical Chemistry Department, University of Wuppertal, 42119 Wuppertal, Germany
| | - Peter Wiesen
- Physical & Theoretical Chemistry Department, University of Wuppertal, 42119 Wuppertal, Germany
| | | | | | | |
Collapse
|
2
|
Zühlke M, Genin L, Riebe D, Beitz T. Selective ionization of marker molecules in fuels by laser-based ion mobility spectrometry (LIMS). ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:864-872. [PMID: 38240373 DOI: 10.1039/d3ay01994b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Careful quality control of complex matrices such as fuels and food is necessary due to the prevalence of counterfeit and pirated goods in global trade. The addition of taggants (indicator substances) to products or their packaging helps to ensure traceability. In order to prevent the mixing of different liquid products, such as different taxed fuels, invisible labelling (marker) can be used to detect illegal activities. This study investigates the qualitative and quantitative analysis of markers in complex fuel matrices using Resonance-Enhanced Multiphoton Ionisation (REMPI) Ion Mobility Spectrometry (IMS). The potential of REMPI as a selective ionisation technique for the detection of markers is highlighted, particularly with respect to minimizing matrix background and the possibility of detection without chromatographic pre-separation. Finding a suitable marker-wavelength combination that provides a suitable marker-to-matrix ratio allows selective ionization of markers while minimising matrix background. Matrix analysis shows that higher excitation wavelengths result in reduced matrix signals, with the low intensities observed at 355 nm for diesel and petrol matrices. Several candidate markers are evaluated based on the criteria of intense signal at 355 nm and non-leachability for the low tax labelling. The analytical performance of selected markers is evaluated, with a focus on the charge transfer reaction (CTR) between markers and matrix components. Our findings demonstrate the potential of REMPI-IMS for marker analysis in fuels without the need for chromatographic pre-separation, providing a promising approach for detecting illegal or fraudulent activities in the supply chain.
Collapse
Affiliation(s)
- Martin Zühlke
- University of Potsdam, Physical Chemistry, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Leonard Genin
- University of Potsdam, Physical Chemistry, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Daniel Riebe
- University of Potsdam, Physical Chemistry, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Toralf Beitz
- University of Potsdam, Physical Chemistry, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| |
Collapse
|
3
|
Milani NBL, van Gilst E, Pirok BWJ, Schoenmakers PJ. Comprehensive two-dimensional gas chromatography- A discussion on recent innovations. J Sep Sci 2023; 46:e2300304. [PMID: 37654057 DOI: 10.1002/jssc.202300304] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/16/2023] [Accepted: 08/19/2023] [Indexed: 09/02/2023]
Abstract
Although comprehensive 2-D GC is an established and often applied analytical method, the field is still highly dynamic thanks to a remarkable number of innovations. In this review, we discuss a number of recent developments in comprehensive 2-D GC technology. A variety of modulation methods are still being actively investigated and many exciting improvements are discussed in this review. We also review interesting developments in detection methods, retention modeling, and data analysis.
Collapse
Affiliation(s)
- Nino B L Milani
- Van't Hoff Institute for Molecular Science (HIMS), University of Amsterdam, Amsterdam, the Netherlands
| | - Eric van Gilst
- Van't Hoff Institute for Molecular Science (HIMS), University of Amsterdam, Amsterdam, the Netherlands
| | - Bob W J Pirok
- Van't Hoff Institute for Molecular Science (HIMS), University of Amsterdam, Amsterdam, the Netherlands
| | - Peter J Schoenmakers
- Van't Hoff Institute for Molecular Science (HIMS), University of Amsterdam, Amsterdam, the Netherlands
| |
Collapse
|
4
|
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.
Collapse
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
| | | |
Collapse
|
5
|
Bräkling S, Kroll K, Klee S, Benter T, Kersten H. Hydrogen Plasma-Based Medium Pressure Chemical Ionization Source for GC-TOFMS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:499-509. [PMID: 35164508 DOI: 10.1021/jasms.1c00329] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The construction, critical evaluation, and performance assessment of a medium-pressure (2-13 mbar), high-temperature chemical ionization (CI) source for application in GC-MS is described. The ion source is coupled to a commercial time-of-flight (TOF) mass analyzer. Reagent ions are generated in a two staged process. The first stage uses a filament free, helical resonator plasma (HRP) driven ion source for H3+ generation. Reagent gases, for example, nitrogen, isobutane, and methane are added in a second stage to the H3+ stream, which leads to the formation of final protonation reagents. The GC effluent is added subsequently to the reagent ion gas stream. Designed for the hyphenation with gas chromatography, this GC-CI-TOFMS combination produces GC limited Gaussian peak shapes even for high boiling point compounds. Limits of detection for the compounds investigated are determined as 0.4-1.2 pg on column with nitrogen, 0.6-12.6 pg with isobutane, and 2 pg to >25 pg with methane as reagent gas, respectively. An EPA 8270 LCS mix containing 78 main EPA pollutants is used to evaluate the selectivity of the different reagent ions. Using nitrogen as reagent gas, 74 of 78 compounds are detected. In comparison, 41 of 78 compounds and 62 of 78 compounds are detected with isobutane or methane as CI reagent gas, respectively.
Collapse
Affiliation(s)
- Steffen Bräkling
- TOFWERK AG, 3645 Thun, Switzerland
- Department of Physical and Theoretical Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
| | - Kai Kroll
- Department of Physical and Theoretical Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
| | | | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
| | - Hendrik Kersten
- Department of Physical and Theoretical Chemistry, University of Wuppertal, 42119 Wuppertal, Germany
| |
Collapse
|
6
|
Dang M, Liu R, Dong F, Liu B, Hou K. Vacuum ultraviolet photoionization on-line mass spectrometry: instrumentation developments and applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
7
|
Unraveling the Complex Olefin Isomer Mixture Using Two-Dimensional Gas Chromatography-Photoionization-Time of Flight Mass Spectrometry. J Chromatogr A 2021; 1645:462103. [PMID: 33848660 DOI: 10.1016/j.chroma.2021.462103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 11/22/2022]
Abstract
Commercial dodecenes are a complex chemical mixture with a majority of C12 olefins and minority of C8-18 olefins. Structurally, dodecene products may consist of straight-chain alkenes, branched alkenes, as well as cyclic hydrocarbons. Due to the difference of feeds and catalysts used in the oligomerization reaction, the composition of the dodecenes is complex and their properties are very different. Knowing the complex composition of dodecenes can help tune the production process and select the appropriate products according to their end use. To reveal the complex profile of dodecenes, an analytical method using two-dimensional gas chromatography (GC×GC) coupled photoionization (PI) - time of flight mass spectrometry (TOFMS) was developed in this study. A conventional (nonpolar × polar) column combination (non-polar column as 1st dimension and mid-polar column as 2nd dimension) was selected. The analytical condition of GC was optimized using fractional factorial experimental design (DoE). Olefin congener grouping by carbon chain length and double bond equivalent (DBE) was achieved based on the detection of molecular ions by PI-TOFMS. Grouping of dodecenes by linear, mono-branched, di- and tri-branched subgroups was achieved based on branching index (BI) under the assumption of no retention time (RT) overlap among subgroups. Certain dodecene isomers were identified by retention index (RI) and further confirmed by PI mass spectra. The information altogether provided a multimodal characterization possibility to be used with statistical tools. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) of seventeen dodecene samples explained the composition variance between catalysts solid phosphoric acid and zeolite, as well as between feeds with C4 and without C4.
Collapse
|
8
|
Gas chromatography in combination with fast high-resolution time-of-flight mass spectrometry: Technical overview and perspectives for data visualization. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.115677] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
9
|
Qian K, Wang FC. Compositional Analysis of Heavy Petroleum Distillates by Comprehensive Two-dimensional Gas Chromatography, Field Ionization and High-resolution Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2785-2794. [PMID: 31741268 DOI: 10.1007/s13361-019-02349-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/12/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
We report recent progresses of combining comprehensive two-dimensional gas chromatography (2DGC or GC × GC) separation, field ionization (FI), and time-of-flight mass spectrometry (TOF MS) for the detailed analysis of vacuum gas oil distillation (VGO) cuts. 2DGC separates petroleum molecules by the combination of boiling point and polarity. FI generates molecule ions-only mass spectra. TOF MS allows accurate mass analysis of hydrocarbon molecules. A new data analysis strategy is implemented for compositional analysis. First, all masses were separated into nominal mass classes. Since petroleum homologues have unique Kendrick mass defects (KMD), KMD plots were generated for easy recognition of homologues series within each nominal mass class. Finally, KMD windows were imposed for complete resolution of petroleum molecules. Using this approach, a total of 16 hydrocarbon types, 14 sulfur types, and their carbon number distributions were determined in the three VGO distillation cuts. Two series of geological biomarkers were also revealed by the analysis.
Collapse
Affiliation(s)
- Kuangnan Qian
- ExxonMobil Research Engineering Company, 1545 Route 22 East, Annandale, NJ, 08801, USA.
| | - Frank C Wang
- ExxonMobil Research Engineering Company, 1545 Route 22 East, Annandale, NJ, 08801, USA
| |
Collapse
|
10
|
Chen X, Hua L, Jiang J, Hu F, Wan N, Li H. Multi-capillary column high-pressure photoionization time-of-flight mass spectrometry and its application for online rapid analysis of flavor compounds. Talanta 2019; 201:33-39. [PMID: 31122430 DOI: 10.1016/j.talanta.2019.03.103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/23/2019] [Accepted: 03/30/2019] [Indexed: 12/15/2022]
Abstract
High-pressure photoionization time-of-flight mass spectrometry (HPPI-TOFMS) is a versatile and highly sensitive analytical technique for online and real-time analysis of trace volatile organic compounds in complex mixtures. However, discrimination of isomers is usually a great challenge for the soft ionization method, and matrix effect is also inevitable under high pressure in the HPPI source. In this work, we describe a first attempt to develop a two-dimensional (2D) hyphenated instrument by coupling of a multi-capillary column (MCC) with a HPPI-TOFMS to overcome these problems. The capability of the MCC-HPPI-TOFMS for discrimination of isomeric compounds and elimination of the matrix effect was demonstrated by analyzing flavor mixtures. With the merits of fast separation, soft ionization and high detection sensitivity, satisfactory effects in the 2D analysis were achieved, despite the relatively low chromatographic resolution of MCC. As a result, three isomers, eucalyptol, l-menthone and linalool, in a flavor mixture were successfully categorized within 90 s, and the matrix effect caused by solvent ethanol was significantly eliminated as well. The limits of detection (LODs) down to sub-ppbv level were achieved for the investigated five flavor compounds without any enrichment process, and an excellent repeatability was obtained with the relative standard deviations (RSDs) of signal intensities ≤5%. The MCC-HPPI-TOFMS system was preliminarily applied for rapid and online analysis of flavor compounds in the exhaled gas of a volunteer after mouth rinsing with a gargle product. The rapid changes of the three flavor compounds, as well as the steady endogenous metabolite acetone, in the exhaled gas were successfully determined with a time-resolution of only 1.5 min.
Collapse
Affiliation(s)
- Xuan Chen
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China.
| | - Lei Hua
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, People's Republic of China
| | - Jichun Jiang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, People's Republic of China
| | - Fan Hu
- Henan Province Medical Instrument Testing Institute, 79 Xiongerhe Road, Zhengzhou, 450018, People's Republic of China
| | - Ningbo Wan
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China
| | - Haiyang Li
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning, 116023, People's Republic of China
| |
Collapse
|
11
|
Application of Vacuum Ultraviolet Single-photon Ionization Mass Spectrometer in Online Analysis of Volatile Organic Compounds. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2019. [DOI: 10.1016/s1872-2040(19)61170-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
12
|
Characterization of a heroin manufacturing process based on acidic extracts by combining complementary information from two-dimensional gas chromatography and high resolution mass spectrometry. Forensic Chem 2017. [DOI: 10.1016/j.forc.2017.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
13
|
Worton DR, Decker M, Isaacman-VanWertz G, Chan AWH, Wilson KR, Goldstein AH. Improved molecular level identification of organic compounds using comprehensive two-dimensional chromatography, dual ionization energies and high resolution mass spectrometry. Analyst 2017; 142:2395-2403. [PMID: 28555694 DOI: 10.1039/c7an00625j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A new analytical methodology combining comprehensive two-dimensional gas chromatography (GC×GC), dual ionization energies and high resolution time of flight mass spectrometry has been developed that improves molecular level identification of organic compounds in complex environmental samples. GC×GC maximizes compound separation providing cleaner mass spectra by minimizing erroneous fragments from interferences and co-eluting peaks. Traditional electron ionization (EI, 70 eV) provides MS fragmentation patterns that can be matched to published EI MS libraries while vacuum ultraviolet photoionization (VUV, 10.5 eV) yields MS with reduced fragmentation enhancing the abundance of the molecular ion providing molecular formulas when combined with high resolution mass spectrometry. We demonstrate this new approach by applying it to a sample of organic aerosol. In this sample, 238 peaks were matched to EI MS library data with FM ≥ 800 but a fifth (42 compounds) were determined to be incorrectly identified because the molecular formula was not confirmed by the VUV MS data. This highlights the importance of using a complementary technique to confirm compound identifications even for peaks with very good matching statistics. In total, 171 compounds were identified by EI MS matching to library spectra with confirmation of the molecular formula from the high resolution VUV MS data and were not dependent on the matching statistics being above a threshold value. A large number of unidentified peaks were still observed with FM < 800, which in routine analysis would typically be neglected. Where possible, these peaks were assigned molecular formulas from the VUV MS data (211 in total). In total, the combination of EI and VUV MS data provides more than twice as much molecular level peak information than traditional approaches and improves confidence in the identification of individual organic compounds. The molecular formula data from the VUV MS data was used, in conjunction with GC×GC retention times and the observed EI MS, to generate a new, searchable EI MS library compatible with the standard NIST MS search program. This library is deliberately dynamic and editable so that other end users can add new entries and update existing entries as new information becomes available.
Collapse
Affiliation(s)
- David R Worton
- Department of Environmental Sciences Policy and Management, University of California, Berkeley, CA 94720, USA.
| | - Monika Decker
- Department of Environmental Sciences Policy and Management, University of California, Berkeley, CA 94720, USA.
| | - Gabriel Isaacman-VanWertz
- Department of Environmental Sciences Policy and Management, University of California, Berkeley, CA 94720, USA.
| | - Arthur W H Chan
- Department of Environmental Sciences Policy and Management, University of California, Berkeley, CA 94720, USA.
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Allen H Goldstein
- Department of Environmental Sciences Policy and Management, University of California, Berkeley, CA 94720, USA. and Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA
| |
Collapse
|
14
|
Hewett DM, Bocklitz S, Tabor DP, Sibert Iii EL, Suhm MA, Zwier TS. Identifying the first folded alkylbenzene via ultraviolet, infrared, and Raman spectroscopy of pentylbenzene through decylbenzene. Chem Sci 2017; 8:5305-5318. [PMID: 30510673 PMCID: PMC6223349 DOI: 10.1039/c7sc02027a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/22/2017] [Indexed: 01/19/2023] Open
Abstract
The shortest possible single-chain alkylbenzene to exist in a folded conformation is determined using spectroscopic and theoretical techniques.
The conformational preferences of pentyl- through decylbenzene are studied under jet-cooled conditions in the gas phase. Laser-induced fluorescence excitation spectra, fluorescence-dip infrared spectra in the alkyl CH stretch region, and Raman spectra are combined to provide assignments for the observed conformers. Density functional theory calculations at the B3LYP-D3BJ/def2TZVP level of theory provide relative energies and normal mode vibrations that serve as inputs for an anharmonic local mode theory introduced in earlier work on alkylbenzenes with n = 2–4. This model explicitly includes anharmonic mixing of the CH stretch modes with the overtones of scissors/bend modes of the CH2 and CH3 groups in the alkyl chain, and is used to assign and interpret the single-conformation IR spectra. In octylbenzene, a pair of LIF transitions shifted –92 and –78 cm–1 from the all-trans electronic origin have unique alkyl CH stretch transitions that are fit by the local model to a g1g3g4 conformation in which the alkyl chain folds back over the aromatic ring π cloud. Its calculated energy is only 1.0 kJ mol–1 above the all-trans global minimum. This fold is at an alkyl chain length less than half that of the pure alkanes (n = 18), consistent with a smaller energy cost for the g1 dihedral and the increased dispersive interaction of the chain with the π cloud. Local site frequencies for the entire set of conformers from the local mode model show ‘edge effects’ that raise the site frequencies of CH2(1) and CH2(2) due to the phenyl ring and CH2(n – 1) due to the methyl group. The g1g3g4 conformer also shows local sites shifted up in frequency at CH2(3) and CH2(6) due to interaction with the π cloud.
Collapse
Affiliation(s)
- Daniel M Hewett
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
| | - Sebastian Bocklitz
- Institut für Physikalische Chemie , Universität Göttingen , Göttingen , Germany
| | - Daniel P Tabor
- Department of Chemistry , University of Wisconsin-Madison , Madison , WI 53706 , USA .
| | - Edwin L Sibert Iii
- Department of Chemistry , University of Wisconsin-Madison , Madison , WI 53706 , USA .
| | - Martin A Suhm
- Institut für Physikalische Chemie , Universität Göttingen , Göttingen , Germany
| | - Timothy S Zwier
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
| |
Collapse
|
15
|
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.
Collapse
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 .
| |
Collapse
|
16
|
Gröger T, Gruber B, Harrison D, Saraji-Bozorgzad M, Mthembu M, Sutherland A, Zimmermann R. A Vacuum Ultraviolet Absorption Array Spectrometer as a Selective Detector for Comprehensive Two-Dimensional Gas Chromatography: Concept and First Results. Anal Chem 2016; 88:3031-9. [DOI: 10.1021/acs.analchem.5b02472] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Thomas Gröger
- Joint
Mass Spectrometry Centre,
Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Joint
Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr. Lorenz Weg 1, 18051 Rostock, Germany
| | - Beate Gruber
- Joint
Mass Spectrometry Centre,
Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Joint
Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr. Lorenz Weg 1, 18051 Rostock, Germany
| | - Dale Harrison
- VUV Analytics, Inc., Austin, Texas 78717, United States
| | | | - Makhosazana Mthembu
- Joint
Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr. Lorenz Weg 1, 18051 Rostock, Germany
| | - Aimée Sutherland
- Joint
Mass Spectrometry Centre,
Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Joint
Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr. Lorenz Weg 1, 18051 Rostock, Germany
| | - Ralf Zimmermann
- Joint
Mass Spectrometry Centre,
Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Joint
Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr. Lorenz Weg 1, 18051 Rostock, Germany
| |
Collapse
|
17
|
Otto S, Streibel T, Erdmann S, Klingbeil S, Schulz-Bull D, Zimmermann R. Pyrolysis-gas chromatography-mass spectrometry with electron-ionization or resonance-enhanced-multi-photon-ionization for characterization of polycyclic aromatic hydrocarbons in the Baltic Sea. MARINE POLLUTION BULLETIN 2015; 99:35-42. [PMID: 26277803 DOI: 10.1016/j.marpolbul.2015.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/31/2015] [Accepted: 08/02/2015] [Indexed: 06/04/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAH), as a part of dissolved organic matter (DOM), are environmental pollutants of the marine compartment. This study investigates the origin of PAH, which is supposed to derive mainly from anthropogenic activities, and their alteration along the salinity gradient of the Baltic Sea. Pyrolysis in combination with gas chromatography and two mass selective detectors in one measurement cycle are utilized as a tool for an efficient trace analysis of such complex samples, by which it is possible to detect degradation products of high molecular structures. Along the north-south transect of the Baltic Sea a slightly rising trend for PAH is visible. Their concentration profiles correspond to the ship traffic as a known anthropogenic source, underlined by the value of special isomer ratios such as phenanthrene and anthracene (0.31-0.45) or pyrene and fluoranthene (0.44-0.53). The detection of naphthalene and the distribution of its alkylated representatives support this statement.
Collapse
Affiliation(s)
- Stefan Otto
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany
| | - Thorsten Streibel
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Institute of Ecological Chemistry, Helmholtz Zentrum München-German Research Center of Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
| | - Sabrina Erdmann
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany
| | - Sophie Klingbeil
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany
| | - Detlef Schulz-Bull
- Marine Chemistry, Leibniz Institute for Baltic Sea Research, Seestrasse 15, 18119 Warnemünde, Rostock, Germany
| | - Ralf Zimmermann
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Institute of Ecological Chemistry, Helmholtz Zentrum München-German Research Center of Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| |
Collapse
|
18
|
Otto S, Streibel T, Erdmann S, Sklorz M, Schulz-Bull D, Zimmermann R. Application of pyrolysis-mass spectrometry and pyrolysis-gas chromatography-mass spectrometry with electron-ionization or resonance-enhanced-multi-photon ionization for characterization of crude oils. Anal Chim Acta 2015; 855:60-9. [PMID: 25542090 DOI: 10.1016/j.aca.2014.11.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/20/2014] [Accepted: 11/23/2014] [Indexed: 01/29/2023]
Abstract
A novel analytical system for gas-chromatographic investigation of complex samples has been developed, that combines the advantages of several analytical principles to enhance the analytical information. Decomposition of high molecular weight structures is achieved by pyrolysis and a high separation capacity due to the chromatographic step provides both an universal as well as a selective and sensitive substance detection. The latter is achieved by simultaneously applying electron ionization quadrupole mass spectrometry (EI-QMS) for structural elucidation and [1+1]-resonance-enhanced-multi-photon ionization (REMPI) combined with time-of-flight mass spectrometry (ToFMS). The system has been evaluated and tested with polycyclic aromatic hydrocarbon (PAH) standards. It was applied to crude oil samples for the first time. In such highly complex samples several thousands of compounds are present and the identification especially of low concentrated chemical species such as PAH or their polycyclic aromatic sulfur containing heterocyclic (PASH) derivatives is often difficult. Detection of unalkylated and alkylated PAH together with PASH is considerably enhanced by REMPI-ToFMS, at times revealing aromatic structures which are not observable by EI-QMS due to their low abundance. On the other hand, the databased structure proposals of the EI-QMS analysis are needed to confirm structural information and isomers distinction. The technique allows a complex structure analysis as well as selective assessment of aromatic substances in one measurement. Information about the content of sulfur containing compounds plays a significant role for the increase of efficiency in the processing of petroleum.
Collapse
Affiliation(s)
- Stefan Otto
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany
| | - Thorsten Streibel
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Institute of Ecological Chemistry, Helmholtz Zentrum München-German Research Center of Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
| | - Sabrina Erdmann
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany
| | - Martin Sklorz
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Institute of Ecological Chemistry, Helmholtz Zentrum München-German Research Center of Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Detlef Schulz-Bull
- Marine Chemistry, Leibniz Institute for Baltic Sea Research, Warnemünde, Seestrasse 15, 18119 Rostock, Germany
| | - Ralf Zimmermann
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Institute of Ecological Chemistry, Helmholtz Zentrum München-German Research Center of Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| |
Collapse
|
19
|
Chin ST, Marriott PJ. Multidimensional gas chromatography beyond simple volatiles separation. Chem Commun (Camb) 2014; 50:8819-33. [DOI: 10.1039/c4cc02018a] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
20
|
Isaacman G, Chan AWH, Nah T, Worton DR, Ruehl CR, Wilson KR, Goldstein AH. Heterogeneous OH oxidation of motor oil particles causes selective depletion of branched and less cyclic hydrocarbons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10632-10640. [PMID: 22947099 DOI: 10.1021/es302768a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Motor oil serves as a useful model system for atmospheric oxidation of hydrocarbon mixtures typical of anthropogenic atmospheric particulate matter, but its complexity often prevents comprehensive chemical speciation. In this work we fully characterize this formerly "unresolved complex mixture" at the molecular level using recently developed soft ionization gas chromatography techniques. Nucleated motor oil particles are oxidized in a flow tube reactor to investigate the relative reaction rates of observed hydrocarbon classes: alkanes, cycloalkanes, bicycloalkanes, tricycloalkanes, and steranes. Oxidation of hydrocarbons in a complex aerosol is found to be efficient, with approximately three-quarters (0.72 ± 0.06) of OH collisions yielding a reaction. Reaction rates of individual hydrocarbons are structurally dependent: compared to normal alkanes, reaction rates increased by 20-50% with branching, while rates decreased ∼20% per nonaromatic ring present. These differences in rates are expected to alter particle composition as a function of oxidation, with depletion of branched and enrichment of cyclic hydrocarbons. Due to this expected shift toward ring-opening reactions heterogeneous oxidation of the unreacted hydrocarbon mixture is less likely to proceed through fragmentation pathways in more oxidized particles. Based on the observed oxidation-induced changes in composition, isomer-resolved analysis has potential utility for determining the photochemical age of atmospheric particulate matter with respect to heterogeneous oxidation.
Collapse
Affiliation(s)
- Gabriel Isaacman
- Environmental Science, Policy, and Management, University of California, Berkeley, California, United States.
| | | | | | | | | | | | | |
Collapse
|
21
|
Nizio KD, McGinitie TM, Harynuk JJ. Comprehensive multidimensional separations for the analysis of petroleum. J Chromatogr A 2012; 1255:12-23. [DOI: 10.1016/j.chroma.2012.01.078] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/24/2012] [Accepted: 01/26/2012] [Indexed: 12/16/2022]
|
22
|
|
23
|
Isaacman G, Wilson KR, Chan AWH, Worton DR, Kimmel JR, Nah T, Hohaus T, Gonin M, Kroll JH, Worsnop DR, Goldstein AH. Improved Resolution of Hydrocarbon Structures and Constitutional Isomers in Complex Mixtures Using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry. Anal Chem 2012; 84:2335-42. [DOI: 10.1021/ac2030464] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gabriel Isaacman
- Environmental Science, Policy,
and Management, University of California, Berkeley, California, United States
| | - Kevin R. Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California,
United States
| | - Arthur W. H. Chan
- Environmental Science, Policy,
and Management, University of California, Berkeley, California, United States
| | - David R. Worton
- Environmental Science, Policy,
and Management, University of California, Berkeley, California, United States
- Aerosol Dynamics Inc., Berkeley, California, United States
| | - Joel R. Kimmel
- Center for Aerosol and Cloud
Chemistry, Aerodyne Research, Inc., Billerica,
Massachusetts, United States
- Cooperative Institute for Research
in the Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, United States
- Tofwerk AG, Thun, Switzerland
| | - Theodora Nah
- Chemistry, University of California, Berkeley, California, United States
| | - Thorsten Hohaus
- Center for Aerosol and Cloud
Chemistry, Aerodyne Research, Inc., Billerica,
Massachusetts, United States
| | | | - Jesse H. Kroll
- Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts,
United States
- Chemical
Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts,
United States
| | - Douglas R. Worsnop
- Center for Aerosol and Cloud
Chemistry, Aerodyne Research, Inc., Billerica,
Massachusetts, United States
| | - Allen H. Goldstein
- Environmental Science, Policy,
and Management, University of California, Berkeley, California, United States
- Environmental
and Energy Technologies
Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States
- Civil and Environmental Engineering, University of California, Berkeley, California, United
States
| |
Collapse
|
24
|
Arsene C, Vione D, Grinberg N, Olariu RI. GC × GC-MS HYPHENATED TECHNIQUES FOR THE ANALYSIS OF VOLATILE ORGANIC COMPOUNDS IN AIR. J LIQ CHROMATOGR R T 2011. [DOI: 10.1080/10826076.2011.587749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Cecilia Arsene
- a Faculty of Chemistry, Laboratory of Analytical Chemistry, “Al. I. Cuza” University of Iasi , Iasi, Romania
| | - Davide Vione
- b Dipartimento di Chimica Analitica , Università di Torino , Torino, Italy
- c Centro Interdipartimentale NatRisk, Università di Torino , Grugliasco (TO), Italy
| | - Nelu Grinberg
- d Boehringer Ingelheim Pharmaceuticals Inc. , Ridgefield, Connecticut, USA
| | - Romeo Iulian Olariu
- a Faculty of Chemistry, Laboratory of Analytical Chemistry, “Al. I. Cuza” University of Iasi , Iasi, Romania
| |
Collapse
|
25
|
Eschner MS, Selmani I, Gröger TM, Zimmermann R. Online Comprehensive Two-Dimensional Characterization of Puff-by-Puff Resolved Cigarette Smoke by Hyphenation of Fast Gas Chromatography to Single-Photon Ionization Time-of-Flight Mass Spectrometry: Quantification of Hazardous Volatile Organic Compounds. Anal Chem 2011; 83:6619-27. [DOI: 10.1021/ac201070j] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Markus S. Eschner
- Joint Mass Spectrometry Centre, Cooperation Group “Comprehensive Molecular Analytics”, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Ismailhaki Selmani
- Joint Mass Spectrometry Centre, Cooperation Group “Comprehensive Molecular Analytics”, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Thomas M. Gröger
- Joint Mass Spectrometry Centre, Cooperation Group “Comprehensive Molecular Analytics”, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Ralf Zimmermann
- Joint Mass Spectrometry Centre, Cooperation Group “Comprehensive Molecular Analytics”, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
- Environmental Chemistry, Bavarian Institute of Applied Environmental Research and Technology GmbH, Am Mittleren Moos 46, 86167 Augsburg, Germany
| |
Collapse
|
26
|
Eschner MS, Gröger TM, Horvath T, Gonin M, Zimmermann R. Quasi-Simultaneous Acquisition of Hard Electron Ionization and Soft Single-Photon Ionization Mass Spectra during GC/MS Analysis by Rapid Switching between Both Ionization Methods: Analytical Concept, Setup, and Application on Diesel Fuel. Anal Chem 2011; 83:3865-72. [DOI: 10.1021/ac200356t] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Markus S. Eschner
- Joint Mass Spectrometry Centre, Cooperation Group “Analysis of Complex Molecular Systems”, Institute of Ecological Chemistry, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Thomas M. Gröger
- Joint Mass Spectrometry Centre, Cooperation Group “Analysis of Complex Molecular Systems”, Institute of Ecological Chemistry, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | | | - Marc Gonin
- Tofwerk AG, Uttigenstrasse 22, 3600 Thun, Switzerland
| | - Ralf Zimmermann
- Joint Mass Spectrometry Centre, Cooperation Group “Analysis of Complex Molecular Systems”, Institute of Ecological Chemistry, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
- Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, Institute of Chemistry, University of Rostock, Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
- BIfA—Bavarian Institute of Applied Environmental Research and Technology GmbH, Am Mittleren Moos 46, 86167 Augsburg, Germany
| |
Collapse
|