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Hupatz H, Rahu I, Wang WC, Peets P, Palm EH, Kruve A. Critical review on in silico methods for structural annotation of chemicals detected with LC/HRMS non-targeted screening. Anal Bioanal Chem 2024:10.1007/s00216-024-05471-x. [PMID: 39138659 DOI: 10.1007/s00216-024-05471-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/22/2024] [Accepted: 07/24/2024] [Indexed: 08/15/2024]
Abstract
Non-targeted screening with liquid chromatography coupled to high-resolution mass spectrometry (LC/HRMS) is increasingly leveraging in silico methods, including machine learning, to obtain candidate structures for structural annotation of LC/HRMS features and their further prioritization. Candidate structures are commonly retrieved based on the tandem mass spectral information either from spectral or structural databases; however, the vast majority of the detected LC/HRMS features remain unannotated, constituting what we refer to as a part of the unknown chemical space. Recently, the exploration of this chemical space has become accessible through generative models. Furthermore, the evaluation of the candidate structures benefits from the complementary empirical analytical information such as retention time, collision cross section values, and ionization type. In this critical review, we provide an overview of the current approaches for retrieving and prioritizing candidate structures. These approaches come with their own set of advantages and limitations, as we showcase in the example of structural annotation of ten known and ten unknown LC/HRMS features. We emphasize that these limitations stem from both experimental and computational considerations. Finally, we highlight three key considerations for the future development of in silico methods.
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Affiliation(s)
- Henrik Hupatz
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius Väg 16, 114 18, Stockholm, Sweden
- Stockholm University Center for Circular and Sustainable Systems (SUCCeSS), Stockholm University, 106 91, Stockholm, Sweden
| | - Ida Rahu
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius Väg 16, 114 18, Stockholm, Sweden.
| | - Wei-Chieh Wang
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius Väg 16, 114 18, Stockholm, Sweden
| | - Pilleriin Peets
- Institute of Biodiversity, Faculty of Biological Science, Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Emma H Palm
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 6 Avenue du Swing, 4367, Belvaux, Luxembourg
| | - Anneli Kruve
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius Väg 16, 114 18, Stockholm, Sweden.
- Stockholm University Center for Circular and Sustainable Systems (SUCCeSS), Stockholm University, 106 91, Stockholm, Sweden.
- Department of Environmental Science, Stockholm University, Svante Arrhenius Väg 8, 114 18, Stockholm, Sweden.
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Jobst KJ, Penney C, Burgers PC. Why are nH-perfluoroalkanoate ions more mobile than expected? Implications for identifying an emerging environmental pollutant. Chem Commun (Camb) 2024; 60:7894-7897. [PMID: 38979952 DOI: 10.1039/d4cc02762k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
nH-Perfluoroalkyl carboxylic acids (nH-PFCAs) are emerging pollutants. Their identification by ion mobility is frustrated by the nH-PFCAs having unexpectedly small collision cross sections (CCS). Theory and experiment agree that this is because nH-PFCA ions undergo internal hydrogen bridging, and this insight will help guide the creation of more accurate methods for pollutant identification.
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Affiliation(s)
- Karl J Jobst
- Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Ave., St. John's A1C 5S7, NL, Canada.
| | - Chloe Penney
- Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Ave., St. John's A1C 5S7, NL, Canada.
| | - Peter C Burgers
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
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Haack A, Schaefer C, Zimmermann S. On the Arrival Time Distribution of Reacting Systems in Ion Mobility Spectrometry. Anal Chem 2024; 96. [PMID: 39009503 PMCID: PMC11295131 DOI: 10.1021/acs.analchem.4c02010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/13/2024] [Accepted: 07/09/2024] [Indexed: 07/17/2024]
Abstract
Ion mobility spectrometry (IMS) is a widely used gas-phase separation technique, particularly when coupled with mass spectrometry (MS). Modern IMS instruments often apply elevated reduced field strengths for improved ion separation and ion focusing. These alter the collision dynamics and further drive ion reaction processes that can change the analyte's structure. As a result, the measured arrival time distribution (ATD) can change with the applied reduced field strengths. In this work, we systematically study how the ion collision dynamics and the ion reaction dynamics, as a function of the reduced field strength, can alter the ATD. To this end, we investigate 2,6-di-tert-butylpyridine, methanol, and ethyl acetate using a home-built drift tube IMS coupled to a home-built MS and extensive first-principles Monte Carlo modeling. We show how elevated reduced field strengths can actually lower resolving power through increased ion diffusion and how the field dependency of the ion mobility can introduce uncertainties to collision cross sections (CCS) calculated from the measured mobilities. On top of the collision dynamics, we show how chemical transformation processes that alter the analyte's CCS, e.g., dynamic clustering or fragmentation, can lead to broadened, shifted, or non-Gaussian ATDs and how sensitive these processes are to the applied field strengths. We highlight how first-principles ion dynamics simulations can help to understand and even harness the mentioned effects.
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Affiliation(s)
- Alexander Haack
- Department of Sensors and
Measurement Technology, Institute of Electrical Engineering and Measurement
Technology, Leibniz University Hannover, 30167 Hannover, Germany
| | - Christoph Schaefer
- Department of Sensors and
Measurement Technology, Institute of Electrical Engineering and Measurement
Technology, Leibniz University Hannover, 30167 Hannover, Germany
| | - Stefan Zimmermann
- Department of Sensors and
Measurement Technology, Institute of Electrical Engineering and Measurement
Technology, Leibniz University Hannover, 30167 Hannover, Germany
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Song XC, Canellas E, Dreolin N, Goshawk J, Lv M, Qu G, Nerin C, Jiang G. Application of Ion Mobility Spectrometry and the Derived Collision Cross Section in the Analysis of Environmental Organic Micropollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21485-21502. [PMID: 38091506 PMCID: PMC10753811 DOI: 10.1021/acs.est.3c03686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 12/27/2023]
Abstract
Ion mobility spectrometry (IMS) is a rapid gas-phase separation technique, which can distinguish ions on the basis of their size, shape, and charge. The IMS-derived collision cross section (CCS) can serve as additional identification evidence for the screening of environmental organic micropollutants (OMPs). In this work, we summarize the published experimental CCS values of environmental OMPs, introduce the current CCS prediction tools, summarize the use of IMS and CCS in the analysis of environmental OMPs, and finally discussed the benefits of IMS and CCS in environmental analysis. An up-to-date CCS compendium for environmental contaminants was produced by combining CCS databases and data sets of particular types of environmental OMPs, including pesticides, drugs, mycotoxins, steroids, plastic additives, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), as well as their well-known transformation products. A total of 9407 experimental CCS values from 4170 OMPs were retrieved from 23 publications, which contain both drift tube CCS in nitrogen (DTCCSN2) and traveling wave CCS in nitrogen (TWCCSN2). A selection of publicly accessible and in-house CCS prediction tools were also investigated; the chemical space covered by the training set and the quality of CCS measurements seem to be vital factors affecting the CCS prediction accuracy. Then, the applications of IMS and the derived CCS in the screening of various OMPs were summarized, and the benefits of IMS and CCS, including increased peak capacity, the elimination of interfering ions, the separation of isomers, and the reduction of false positives and false negatives, were discussed in detail. With the improvement of the resolving power of IMS and enhancements of experimental CCS databases, the practicability of IMS in the analysis of environmental OMPs will continue to improve.
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Affiliation(s)
- Xue-Chao Song
- School
of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
- State
Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, EINA, University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
| | - Elena Canellas
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, EINA, University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
| | - Nicola Dreolin
- Waters
Corporation, Stamford
Avenue, Altrincham Road, SK9 4AX Wilmslow, United Kingdom
| | - Jeff Goshawk
- Waters
Corporation, Stamford
Avenue, Altrincham Road, SK9 4AX Wilmslow, United Kingdom
| | - Meilin Lv
- State
Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- Research
Center for Analytical Sciences, Department of Chemistry, College of
Sciences, Northeastern University, 110819 Shenyang, China
| | - Guangbo Qu
- School
of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
- State
Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- Institute
of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Cristina Nerin
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, EINA, University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
| | - Guibin Jiang
- School
of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
- State
Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- Institute
of Environment and Health, Jianghan University, Wuhan 430056, China
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