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Arachchi S, Palma SP, Sanders CI, Xu H, Ghosh Biswas R, Soong R, Simpson AJ, Casabianca LB. Binding Between Antibiotics and Polystyrene Nanoparticles Examined by NMR. ACS ENVIRONMENTAL AU 2022; 3:47-55. [PMID: 36691656 PMCID: PMC9856636 DOI: 10.1021/acsenvironau.2c00047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 01/19/2023]
Abstract
Elucidating the interactions between plastic nanoparticles and small molecules is important to understanding these interactions as they occur in polluted waterways. For example, plastic that breaks down into micro- and nanoscale particles will interact with small molecule pollutants that are also present in contaminated waters. Other components of natural water, such as dissolved organic matter, will also influence these interactions. Here we use a collection of complementary NMR techniques to examine the binding between polystyrene nanoparticles and three common antibiotics, belonging to a class of molecules that are expected to be common in polluted water. Through examination of proton NMR signal intensity, relaxation times, saturation-transfer difference (STD) NMR, and competition STD-NMR, we find that the antibiotics have binding strengths in the order amoxicillin < metronidazole ≪ levofloxacin. Levofloxacin is able to compete for binding sites, preventing the other two antibiotics from binding. The presence of tannic acid disrupts the binding between levofloxacin and the polystyrene nanoparticles, but does not influence the binding between metronidazole and these nanoparticles.
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Affiliation(s)
- Saduni
S. Arachchi
- Department
of Chemistry, Clemson University, Clemson, South Carolina29634, United States
| | - Stephanie P. Palma
- Department
of Chemistry, Clemson University, Clemson, South Carolina29634, United States
| | - Charlotte I. Sanders
- Department
of Chemistry, Clemson University, Clemson, South Carolina29634, United States
| | - Hui Xu
- Department
of Chemistry, Clemson University, Clemson, South Carolina29634, United States
| | - Rajshree Ghosh Biswas
- Department
of Chemistry, University of Toronto Scarborough, Toronto, OntarioM1C 1A4, Canada
| | - Ronald Soong
- Department
of Chemistry, University of Toronto Scarborough, Toronto, OntarioM1C 1A4, Canada
| | - André J. Simpson
- Department
of Chemistry, University of Toronto Scarborough, Toronto, OntarioM1C 1A4, Canada
| | - Leah B. Casabianca
- Department
of Chemistry, Clemson University, Clemson, South Carolina29634, United States,
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2
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Anaraki MT, Lysak DH, Downey K, Kock FVC, You X, Majumdar RD, Barison A, Lião LM, Ferreira AG, Decker V, Goerling B, Spraul M, Godejohann M, Helm PA, Kleywegt S, Jobst K, Soong R, Simpson MJ, Simpson AJ. NMR spectroscopy of wastewater: A review, case study, and future potential. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 126-127:121-180. [PMID: 34852923 DOI: 10.1016/j.pnmrs.2021.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
NMR spectroscopy is arguably the most powerful tool for the study of molecular structures and interactions, and is increasingly being applied to environmental research, such as the study of wastewater. With over 97% of the planet's water being saltwater, and two thirds of freshwater being frozen in the ice caps and glaciers, there is a significant need to maintain and reuse the remaining 1%, which is a precious resource, critical to the sustainability of most life on Earth. Sanitation and reutilization of wastewater is an important method of water conservation, especially in arid regions, making the understanding of wastewater itself, and of its treatment processes, a highly relevant area of environmental research. Here, the benefits, challenges and subtleties of using NMR spectroscopy for the analysis of wastewater are considered. First, the techniques available to overcome the specific challenges arising from the nature of wastewater (which is a complex and dilute matrix), including an examination of sample preparation and NMR techniques (such as solvent suppression), in both the solid and solution states, are discussed. Then, the arsenal of available NMR techniques for both structure elucidation (e.g., heteronuclear, multidimensional NMR, homonuclear scalar coupling-based experiments) and the study of intermolecular interactions (e.g., diffusion, nuclear Overhauser and saturation transfer-based techniques) in wastewater are examined. Examples of wastewater NMR studies from the literature are reviewed and potential areas for future research are identified. Organized by nucleus, this review includes the common heteronuclei (13C, 15N, 19F, 31P, 29Si) as well as other environmentally relevant nuclei and metals such as 27Al, 51V, 207Pb and 113Cd, among others. Further, the potential of additional NMR methods such as comprehensive multiphase NMR, NMR microscopy and hyphenated techniques (for example, LC-SPE-NMR-MS) for advancing the current understanding of wastewater are discussed. In addition, a case study that combines natural abundance (i.e. non-concentrated), targeted and non-targeted NMR to characterize wastewater, along with in vivo based NMR to understand its toxicity, is included. The study demonstrates that, when applied comprehensively, NMR can provide unique insights into not just the structure, but also potential impacts, of wastewater and wastewater treatment processes. Finally, low-field NMR, which holds considerable future potential for on-site wastewater monitoring, is briefly discussed. In summary, NMR spectroscopy is one of the most versatile tools in modern science, with abilities to study all phases (gases, liquids, gels and solids), chemical structures, interactions, interfaces, toxicity and much more. The authors hope this review will inspire more scientists to embrace NMR, given its huge potential for both wastewater analysis in particular and environmental research in general.
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Affiliation(s)
- Maryam Tabatabaei Anaraki
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Daniel H Lysak
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Katelyn Downey
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Flávio Vinicius Crizóstomo Kock
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada; Department of Chemistry, Federal University of São Carlos-SP (UFSCar), São Carlos, SP, Brazil
| | - Xiang You
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Rudraksha D Majumdar
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada; Synex Medical, 2 Bloor Street E, Suite 310, Toronto, ON M4W 1A8, Canada
| | - Andersson Barison
- NMR Center, Federal University of Paraná, CP 19081, 81530-900 Curitiba, PR, Brazil
| | - Luciano Morais Lião
- NMR Center, Institute of Chemistry, Universidade Federal de Goiás, Goiânia 74690-900, Brazil
| | | | - Venita Decker
- Bruker Biospin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | | | - Manfred Spraul
- Bruker Biospin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | | | - Paul A Helm
- Environmental Monitoring & Reporting Branch, Ontario Ministry of the Environment, Toronto M9P 3V6, Canada
| | - Sonya Kleywegt
- Technical Assessment and Standards Development Branch, Ontario Ministry of the Environment, Conservation and Parks, Toronto, ON M4V 1M2, Canada
| | - Karl Jobst
- Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada
| | - Ronald Soong
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Myrna J Simpson
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada
| | - Andre J Simpson
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Toronto M1C1A4, Canada.
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Chaubey B, Singh P, Pal S. Solution-state NMR evaluation of molecular interaction between monoaromatic carboxylic acids and dissolved humic acid. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:17775-17788. [PMID: 33400107 DOI: 10.1007/s11356-020-12092-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Understanding the nature of interactions between the aromatic organic pollutants with dissolved humic acid (HA) is fundamental for the prediction of their environmental fate and subsequent development of efficient remediation methods. The present study employs solution-state 1H/19F NMR methods to investigate the non-covalent interaction between aqueous peat humic acid (Aldrich HA) and monoaromatic carboxylic acids (CA), viz., 2, 6 diflourobenzoic acid (DFBA) and its non-fluorinated analog, benzoic acid (BA). NMR self-diffusion measurement of HA protons confirmed micellar nature indicating possibility of encapsulation of small molecules through host-guest interaction. 19F-1H and 1H-1H saturation transfer difference (STD) experiments reveal the mode of insertion of CA into HA superstructure. The strength of interaction has been evaluated by analyzing T1/T2 relaxation times and self-diffusion coefficients of CA as a function of HA concentration. Association constants extracted for CA-HA complexes from NMR diffusion experiments reflected that the association between DFBA-HA (2.34 mM-1) is significantly higher than that of BA-HA (0.97 mM-1). The experimental outcome reiterated that substitution of -H with halogen atoms (-F in specific) to aromatic ring plays a dominant role in modulating the strength of association and mode of insertion of organic pollutants into HA superstructure. The present study emphasizes that AHA can be a potential remediating agent for organic contaminants due to its superior binding affinity compared to less humified extracted HA (EHA) from Karwar, Rajasthan, India.
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Affiliation(s)
- Bhawna Chaubey
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342037, India
| | - Pooja Singh
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342037, India
| | - Samanwita Pal
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342037, India.
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4
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Chaubey B, Narwal P, Khandelwal A, Pal S. Aqueous photo-degradation of Flupyradifurone (FPD) in presence of a natural Humic Acid (HA): A quantitative solution state NMR analysis. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.112986] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Chaubey B, Pal S. Binding Interaction of Organofluorine–Serum Albumin: A Comparative Ligand-Detected 19F NMR Analysis. J Phys Chem B 2018; 122:9409-9418. [DOI: 10.1021/acs.jpcb.8b06583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Bhawna Chaubey
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Samanwita Pal
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
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Sugiki T, Furuita K, Fujiwara T, Kojima C. Current NMR Techniques for Structure-Based Drug Discovery. Molecules 2018; 23:molecules23010148. [PMID: 29329228 PMCID: PMC6017608 DOI: 10.3390/molecules23010148] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/28/2017] [Accepted: 01/09/2018] [Indexed: 12/22/2022] Open
Abstract
A variety of nuclear magnetic resonance (NMR) applications have been developed for structure-based drug discovery (SBDD). NMR provides many advantages over other methods, such as the ability to directly observe chemical compounds and target biomolecules, and to be used for ligand-based and protein-based approaches. NMR can also provide important information about the interactions in a protein-ligand complex, such as structure, dynamics, and affinity, even when the interaction is too weak to be detected by ELISA or fluorescence resonance energy transfer (FRET)-based high-throughput screening (HTS) or to be crystalized. In this study, we reviewed current NMR techniques. We focused on recent progress in NMR measurement and sample preparation techniques that have expanded the potential of NMR-based SBDD, such as fluorine NMR (19F-NMR) screening, structure modeling of weak complexes, and site-specific isotope labeling of challenging targets.
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Affiliation(s)
- Toshihiko Sugiki
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan.
| | - Kyoko Furuita
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan.
| | | | - Chojiro Kojima
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan.
- Graduate School of Engineering, Yokohama National University, Yokohama 240-8501, Japan.
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7
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Courtier-Murias D, Michel E, Rodts S, Lafolie F. Novel Experimental-Modeling Approach for Characterizing Perfluorinated Surfactants in Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2602-2610. [PMID: 28165731 DOI: 10.1021/acs.est.6b05671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Soil contamination is still poorly understood and modeled in part because of the difficulties of looking inside the "black box" constituted by soils. Here, we investigated the application of a recently developed 1H NMR technique to 19F NMR relaxometry experiments and utilized the results as inputs for an existing model. This novel approach yields 19F T2 NMR relaxation values of any fluorinated contaminant, which are among the most dangerous contaminants, allowing us to noninvasively and directly monitor their fate in soils. Using this protocol, we quantified the amount of a fluorinated xenobiotic (heptafluorobutyric acid, HFBA) in three different environments in soil aggregate packings and monitored contaminant exchange dynamics between these compartments. A model computing HFBA partition dynamics between different soil compartments showed that these three environments corresponded to HFBA in solution (i) between and (ii) inside the soil aggregates and (iii) to HFBA adsorbed to (or strongly interacting with) the soil constituents. In addition to providing a straightforward way of determining the sorption kinetics of any fluorinated contaminant, this work also highlights the strengths of a combined experimental-modeling approach to unambiguously understand experimental data and more generally to study contaminant fate in soils.
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Affiliation(s)
- Denis Courtier-Murias
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 77420 Champs-sur-Marne, France
| | - Eric Michel
- EMMAH, INRA, Université d'Avignon et des Pays de Vaucluse, 84000 Avignon, France
| | - Stéphane Rodts
- Université Paris-Est, Laboratoire Navier (ENPC-IFSTTAR-CNRS), 77420 Champs-sur-Marne, France
| | - François Lafolie
- EMMAH, INRA, Université d'Avignon et des Pays de Vaucluse, 84000 Avignon, France
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8
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Huang YH, Lo WS, Kuo YW, Chen WJ, Lin CH, Shieh FK. Green and rapid synthesis of zirconium metal–organic frameworks via mechanochemistry: UiO-66 analog nanocrystals obtained in one hundred seconds. Chem Commun (Camb) 2017; 53:5818-5821. [DOI: 10.1039/c7cc03105j] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A UiO-66 analog was synthesized in 100 s via water-assisted grinding by the evaluation of linker solubility effects.
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Affiliation(s)
- Yi-Hao Huang
- Department of Chemistry
- National Central University
- Chung Li
- Taiwan
| | - Wei-Shang Lo
- Department of Chemistry
- National Central University
- Chung Li
- Taiwan
| | - Yun-Wei Kuo
- Department of Chemistry
- National Central University
- Chung Li
- Taiwan
| | - Wen-Jin Chen
- Department of Chemistry
- Chung Yuan Christian University
- Chung Li
- Taiwan
| | - Chia-Her Lin
- Department of Chemistry
- Chung Yuan Christian University
- Chung Li
- Taiwan
| | - Fa-Kuen Shieh
- Department of Chemistry
- National Central University
- Chung Li
- Taiwan
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9
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Longstaffe JG, Courtier-Murias D, Simpson AJ. A nuclear magnetic resonance study of the dynamics of organofluorine interactions with a dissolved humic acid. CHEMOSPHERE 2016; 145:307-313. [PMID: 26692506 DOI: 10.1016/j.chemosphere.2015.11.080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/20/2015] [Accepted: 11/21/2015] [Indexed: 06/05/2023]
Abstract
A quantitative understanding of the dynamics of the interactions between organofluorine compounds and humic acids will contribute to an improved understanding of the role that Natural Organic Matter plays as a mediator in the fate, transport and distribution of these contaminants in the environment. Here, Nuclear Magnetic Resonance (NMR) spectroscopy-based diffusion measurements are used to estimate the association dynamics between dissolved humic acid and selected organofluorine compounds: pentafluoroaniline, pentafluorophenol, potassium perfluorooctane sulfonate, and perfluorooctanoic acid. Under the conditions used here, the strength of the association with humic acid increases linearly as temperature decreases for all compounds except for perfluorooctanoic acid, which exhibits divergent behavior with a non-linear decrease in the extent of interaction as temperature decreases. A general interaction mechanism controlled largely by desolvation effects is suggested for all compounds examined here except for perfluorooctanoic acid, which exhibits a specific mode of interaction consistent with a proteinaceous binding site. Reverse Heteronuclear Saturation Transfer Difference NMR is used to confirm the identity and nature of the humic acid binding sites.
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Affiliation(s)
- James G Longstaffe
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada.
| | - Denis Courtier-Murias
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada.
| | - Andre J Simpson
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada.
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10
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Masoom H, Courtier-Murias D, Soong R, Maas WE, Fey M, Kumar R, Monette M, Stronks HJ, Simpson MJ, Simpson AJ. From Spill to Sequestration: The Molecular Journey of Contamination via Comprehensive Multiphase NMR. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13983-13991. [PMID: 26579583 DOI: 10.1021/acs.est.5b03251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Comprehensive multiphase NMR is a novel NMR technique that permits all components (solutions, gels, and solids) to be studied in unaltered natural samples. In this study a wide range of CMP-NMR interaction and editing-based experiments are combined to follow contaminants (pentafluorophenol (PFP) and perfluorooctanoic acid (PFOA)) from the solution state (after a spill) through the gel-state and finally into the true solid-state (sequestered) in an intact water-swollen soil. Kinetics experiments monitoring each phase illustrate PFOA rapidly transfers from solution to the solid phase while for PFP the process is slower with longer residence times in the solution and gel phase. Interaction-based experiments reveal that PFOA enters the soil via its hydrophobic tails and selectively binds to soil microbial protein. PFP sorption shows less specificity exhibiting interactions with a range of gel and solid soil components with a preference toward aromatics (mainly lignin). The results indicate that in addition to more traditional measurements such as Koc, other factors including the influence of the contaminant on the soil-water interface, specific biological interactions, soil composition (content of lignin, protein, etc.) and physical accessibility/swellability of soil organic components will likely be central to better explaining and predicting the true behavior of contaminants in soil.
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Affiliation(s)
- Hussain Masoom
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | | | - Ronald Soong
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | - Werner E Maas
- Bruker BioSpin Corp., Billerica, Massachusetts 01821-3991, United States
| | - Michael Fey
- Bruker BioSpin Corp., Billerica, Massachusetts 01821-3991, United States
| | - Rajeev Kumar
- Bruker BioSpin Canada, Milton, Ontario Canada , L9T 1Y6
| | | | | | - Myrna J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | - André J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
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11
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Mazzei P, Piccolo A. Interactions between natural organic matter and organic pollutants as revealed by NMR spectroscopy. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:667-678. [PMID: 25783763 DOI: 10.1002/mrc.4209] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/13/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Natural organic matter (NOM) plays a critical role in regulating the transport and the fate of organic contaminants in the environment. NMR spectroscopy is a powerful technique for the investigation of the sorption and binding mechanisms between NOM and pollutants, as well as their mutual chemical transformations. Despite NMR relatively low sensibility but due to its wide versatility to investigating samples in the liquid, gel, and solid phases, NMR application to environmental NOM-pollutants relations enables the achievement of specific and complementary molecular information. This report is a brief outline of the potentialities of the different NMR techniques and pulse sequences to elucidate the interactions between NOM and organic pollutants, with and without their labeling with nuclei that enhance NMR sensitivity.
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Affiliation(s)
- Pierluigi Mazzei
- Centro Interdipartimentale per la Risonanza Magnetica Nucleare per l'Ambiente, l'Agro-Alimentare ed i Nuovi Materiali (CERMANU), Università di Napoli Federico II, Via Università 100, 80055, Portici, Italy
| | - Alessandro Piccolo
- Centro Interdipartimentale per la Risonanza Magnetica Nucleare per l'Ambiente, l'Agro-Alimentare ed i Nuovi Materiali (CERMANU), Università di Napoli Federico II, Via Università 100, 80055, Portici, Italy
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12
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Longstaffe JG, Courtier-Murias D, Simpson AJ. The pH-dependence of organofluorine binding domain preference in dissolved humic acid. CHEMOSPHERE 2013; 90:270-275. [PMID: 22863060 DOI: 10.1016/j.chemosphere.2012.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/03/2012] [Accepted: 07/05/2012] [Indexed: 06/01/2023]
Abstract
In this study we explore the relationship between solution pH and the distribution of the binding interactions at different domains of a dissolved humic acid (HA) for three xenobiotics: pentafluoroaniline (PFA), pentafluorophenol (PFP), and hexafluorobenzene (HFB). The components of HA where xenobiotic interactions occur are identified using the (1)H{(19)F} Reverse Heteronuclear Saturation Transfer Difference (RHSTD) Nuclear Magnetic Resonance (NMR) spectroscopy experiment. At low pH, PFA and PFP interact preferentially with aromatic components of HA. Increasing pH reduces this preference. Conversely, HFB interacts with all components of HA equally, across the entire pH range. The possible roles of both aromatic-specific interactions and conformational changes of HA behind these observations are explored. It is shown that T-oriented π-π interactions at π-electron accepting HA structures are slightly stronger for PFA and PFP than for HFB. Using DOSY NMR it is shown that the pH-dependence of the interactions is correlated with changes in the conformation of the carbohydrate components of HA rather than with the aromatic components. It is argued that the observed preference for aromatic HA is caused by restricted access to the non-aromatic components of HA at low pH. These HA components form tightly bound hydrophobic domains due to strong inter- and intra-molecular hydrogen bonds. At high pH, these structures open up, making them more available for interactions with polar compounds.
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Affiliation(s)
- James G Longstaffe
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4.
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13
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Wagstaff JL, Taylor SL, Howard MJ. Recent developments and applications of saturation transfer difference nuclear magnetic resonance (STD NMR) spectroscopy. ACTA ACUST UNITED AC 2013; 9:571-7. [DOI: 10.1039/c2mb25395j] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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14
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Simpson AJ, Simpson MJ, Soong R. Nuclear magnetic resonance spectroscopy and its key role in environmental research. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:11488-11496. [PMID: 22909253 DOI: 10.1021/es302154w] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nuclear magnetic resonance (NMR) is arguably the most powerful and versatile tool in modern science. It has the capability to solve complex structures and interactions in situ even in complex heterogeneous multiphase samples such as soil, plants, and tissues. NMR has vast potential in environmental research and can provide insight into a diverse range of environmental processes at the molecular level be it identifying the binding site in human blood for a specific contaminant or the compositional dynamics of soil with climate change. Modern NMR-based metabonomics is elucidating contaminant toxicity and toxic mode of action rapidly and at sub lethal concentrations. Combined modern NMR approaches provide a powerful framework to better understand carbon cycling and sustainable agriculture, as well as contaminant fate, bioavailability, toxicity, sequestration, and remediation.
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Affiliation(s)
- Andre J Simpson
- Environmental NMR Centre, Department of Chemistry, University of Toronto, Toronto, Canada.
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15
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Longstaffe JG, Courtier-Murias D, Soong R, Simpson MJ, Maas WE, Fey M, Hutchins H, Krishnamurthy S, Struppe J, Alaee M, Kumar R, Monette M, Stronks HJ, Simpson AJ. In-situ molecular-level elucidation of organofluorine binding sites in a whole peat soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10508-10513. [PMID: 22946434 DOI: 10.1021/es3026769] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The chemical nature of xenobiotic binding sites in soils is of vital importance to environmental biogeochemistry. Interactions between xenobiotics and the naturally occurring organic constituents of soils are strongly correlated to environmental persistence, bioaccessibility, and ecotoxicity. Nevertheless, because of the complex structural and chemical heterogeneity of soils, studies of these interactions are most commonly performed indirectly, using correlative methods, fractionation, or chemical modification. Here we identify the organic components of an unmodified peat soil where some organofluorine xenobiotic compounds interact using direct molecular-level methods. Using (19)F→(1)H cross-polarization magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy, the (19)F nuclei of organofluorine compounds are used to induce observable transverse magnetization in the (1)H nuclei of organic components of the soil with which they interact after sorption. The observed (19)F→(1)H CP-MAS spectra and dynamics are compared to those produced using model soil organic compounds, lignin and albumin. It is found that lignin-like components can account for the interactions observed in this soil for heptafluoronaphthol (HFNap) while protein structures can account for the interactions observed for perfluorooctanoic acid (PFOA). This study employs novel comprehensive multi-phase (CMP) NMR technology that permits the application of solution-, gel-, and solid-state NMR experiments on intact soil samples in their swollen state.
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Affiliation(s)
- James G Longstaffe
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, Canada, M1C 1A4
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Courtier-Murias D, Farooq H, Masoom H, Botana A, Soong R, Longstaffe JG, Simpson MJ, Maas WE, Fey M, Andrew B, Struppe J, Hutchins H, Krishnamurthy S, Kumar R, Monette M, Stronks HJ, Hume A, Simpson AJ. Comprehensive multiphase NMR spectroscopy: basic experimental approaches to differentiate phases in heterogeneous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 217:61-76. [PMID: 22425441 DOI: 10.1016/j.jmr.2012.02.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/15/2012] [Indexed: 05/16/2023]
Abstract
Heterogeneous samples, such as soils, sediments, plants, tissues, foods and organisms, often contain liquid-, gel- and solid-like phases and it is the synergism between these phases that determine their environmental and biological properties. Studying each phase separately can perturb the sample, removing important structural information such as chemical interactions at the gel-solid interface, kinetics across boundaries and conformation in the natural state. In order to overcome these limitations a Comprehensive Multiphase-Nuclear Magnetic Resonance (CMP-NMR) probe has been developed, and is introduced here, that permits all bonds in all phases to be studied and differentiated in whole unaltered natural samples. The CMP-NMR probe is built with high power circuitry, Magic Angle Spinning (MAS), is fitted with a lock channel, pulse field gradients, and is fully susceptibility matched. Consequently, this novel NMR probe has to cover all HR-MAS aspects without compromising power handling to permit the full range of solution-, gel- and solid-state experiments available today. Using this technology, both structures and interactions can be studied independently in each phase as well as transfer/interactions between phases within a heterogeneous sample. This paper outlines some basic experimental approaches using a model heterogeneous multiphase sample containing liquid-, gel- and solid-like components in water, yielding separate (1)H and (13)C spectra for the different phases. In addition, (19)F performance is also addressed. To illustrate the capability of (19)F NMR soil samples, containing two different contaminants, are used, demonstrating a preliminary, but real-world application of this technology. This novel NMR approach possesses a great potential for the in situ study of natural samples in their native state.
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Affiliation(s)
- Denis Courtier-Murias
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, ON, Canada M1C 1A4
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