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Dr. James Longstaffe
School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada

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Research Keywords & Expertise

0 Analytical Instrumentation
0 Environmental Chemistry
0 Remediation
0 natural organic matter
0 Soil and groundwater contamination

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Book chapter
Published: 30 January 2021 in Annual Reports on NMR Spectroscopy
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Benchtop NMR spectroscopy has emerged as a practical tool for improved analytical characterization in many applied disciplines. Benchtop NMR spectrometers are built around permanent magnets as opposed to the cryogen-cooled magnets used in conventional NMR spectroscopy. Such instruments are relatively less expensive, compact, and in some instances portable, meaning that they can be installed and employed at locations and facilities where NMR spectroscopy has either not been financially feasible or has been impractical due to physical constraints. The increased commercial availability of these instruments has led to a wealth of studies exploring applications of NMR in many disciplines that have arguable been underserved by conventional NMR spectroscopy. This review discussed recent developments in the design of this new class of NMR instruments, as well as the use of these instruments across many disciplines, including education, process reaction monitoring, materials science, food science, and environmental science.

ACS Style

Janelle Giberson; Julia Scicluna; Nicole Legge; James Longstaffe. Developments in benchtop NMR spectroscopy 2015–2020. Annual Reports on NMR Spectroscopy 2021, 153 -246.

AMA Style

Janelle Giberson, Julia Scicluna, Nicole Legge, James Longstaffe. Developments in benchtop NMR spectroscopy 2015–2020. Annual Reports on NMR Spectroscopy. 2021; ():153-246.

Chicago/Turabian Style

Janelle Giberson; Julia Scicluna; Nicole Legge; James Longstaffe. 2021. "Developments in benchtop NMR spectroscopy 2015–2020." Annual Reports on NMR Spectroscopy , no. : 153-246.

Special issue research article
Published: 29 January 2020 in Magnetic Resonance in Chemistry
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The development of effective remedial technologies for the destruction of environmental pollutants requires the ability to clearly monitor degradation processes. NMR spectroscopy is a powerful tool for understanding reaction progress, however practical considerations often restrict the application of NMR spectroscopy as a tool to better understand the degradation of environmental pollutants. Chief among these restrictions is the limited access smaller environmental research labs and remediation companies have to suitable NMR facilities. Benchtop NMR spectroscopy is a low‐cost and user‐friendly approach to acquire much of the same information as conventional NMR spectroscopy, albeit with reduced sensitivity and resolution. This paper explores the practical application of benchtop NMR spectroscopy to understand the degradation of perfluorooctanoic acid using sodium persulfate, a common reagent for the destruction of groundwater contaminants. It is found that Benchtop 19F NMR spectroscopy is able to monitor the complete degradation of perfluorooctanoic acid into fluoride, however the observation of intermediate degradation products formed, which can be observed using a conventional NMR spectrometer, cannot be readily distinguished from the parent compound when measurements are performed using the benchtop instrument. Under certain reaction conditions the formation of fluorinated structures that are resistant to further degradation are readily observed. Overall, it is shown that benchtop 19F NMR spectroscopy has potential as a quick and reliable tool to assist in the development of remedial technologies for the degradation of fluorinated contaminants.

ACS Style

Kavi Heerah; Stanislaw Waclawek; Julie Konzuk; James G. Longstaffe. Benchtop 19 F NMR spectroscopy as a practical tool for testing of remedial technologies for the degradation of perfluorooctanoic acid, a persistent organic pollutant. Magnetic Resonance in Chemistry 2020, 1 .

AMA Style

Kavi Heerah, Stanislaw Waclawek, Julie Konzuk, James G. Longstaffe. Benchtop 19 F NMR spectroscopy as a practical tool for testing of remedial technologies for the degradation of perfluorooctanoic acid, a persistent organic pollutant. Magnetic Resonance in Chemistry. 2020; ():1.

Chicago/Turabian Style

Kavi Heerah; Stanislaw Waclawek; Julie Konzuk; James G. Longstaffe. 2020. "Benchtop 19 F NMR spectroscopy as a practical tool for testing of remedial technologies for the degradation of perfluorooctanoic acid, a persistent organic pollutant." Magnetic Resonance in Chemistry , no. : 1.

Methods
Published: 19 February 2019 in Environmental Toxicology and Chemistry
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Non‐aqueous phase liquids (NAPLs), composed primarily of organic solvents and other immiscible liquids, can be found in the subsurface at many industrial sites. The chemical composition of NAPL is often complex and, in many instances, difficult to fully characterize using conventional analytical techniques based on targeted compound analysis. Incomplete characterization of NAPL leaves gaps in the understanding of the chemical profile at an impacted site. Previous work has shown that nuclear magnetic resonance spectroscopy (NMR) may be able to assist in the improved characterization of complex NAPL samples. In general, NMR provides an unbiased approach for the analysis of organic compounds as different classes of compounds are all treated and analyzed using the same methods. Additionally, NMR provides unique structural information that can be used to elucidate unknowns. This paper describes the use of NMR spectroscopy as a non‐targeted tool to characterize the composition of NAPL collected from an impacted site. It is shown that NMR can be a complimentary tool to be used in site assessments to help provide improved understanding of NAPL chemistry, leading to the development of improved conceptual site models, and improved strategies for remedial and managerial activities at impacted sites. This article is protected by copyright. All rights reserved

ACS Style

Darcy Fallaise; Julie Konzuk; Carol Cheyne; E. Erin Mack; James G. Longstaffe. Nontargeted Analysis of a Non‐Aqueous‐Phase Liquid From a Chemical Manufacturing Site Using Nuclear Magnetic Resonance Spectroscopy. Environmental Toxicology and Chemistry 2019, 38, 947 -955.

AMA Style

Darcy Fallaise, Julie Konzuk, Carol Cheyne, E. Erin Mack, James G. Longstaffe. Nontargeted Analysis of a Non‐Aqueous‐Phase Liquid From a Chemical Manufacturing Site Using Nuclear Magnetic Resonance Spectroscopy. Environmental Toxicology and Chemistry. 2019; 38 (5):947-955.

Chicago/Turabian Style

Darcy Fallaise; Julie Konzuk; Carol Cheyne; E. Erin Mack; James G. Longstaffe. 2019. "Nontargeted Analysis of a Non‐Aqueous‐Phase Liquid From a Chemical Manufacturing Site Using Nuclear Magnetic Resonance Spectroscopy." Environmental Toxicology and Chemistry 38, no. 5: 947-955.

Research article
Published: 17 December 2018 in Magnetic Resonance in Chemistry
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Non‐Aqueous Phase Liquids (NAPLs) located at the surface of the water table and/or below the water table are often a significant source for groundwater contamination near current or former commercial/industrial facilities. Due to the complex and long history of many industrial sites, these NAPLs often contain a complex mixture of contaminants and as such can be difficult to fully characterize using conventional analytical methods. Remediation and risk assessment activities at sites containing NAPLs may, subsequently, be hindered as the contamination profile may not be fully understood. This paper demonstrates the application of bench‐scale 1H Nuclear Magnetic Resonance (NMR) spectroscopy as a practical tool to assist with the characterization of complex NAPLs. Here, a NAPL collected from a contaminated site situated near a former chemical manufacturing facility was analyzed using a combination of one‐dimensional (1D) 1H NMR spectroscopy and 2‐dimensional (2D) 1H J‐resolved spectroscopy (JRES). It is shown that 1D NMR experiments are useful in the rapid identification of the classes of compounds present, while 2D JRES NMR experiments are useful in identifying specific compounds. The use of benchtop NMR spectroscopy as a simple and cost effective tool to assist in the analysis of contaminated sites may help improve the practical characterization of many heavily contaminated sites, and facilitate improved risk assessments and remedial strategies.

ACS Style

Darcy Fallaise; Hannah Balkwill Tweedie; Julie Konzuk; Carol Cheyne; E. Erin Mack; James G. Longstaffe. Practical application of 1 H benchtop NMR spectroscopy for the characterization of a nonaqueous phase liquid from a contaminated environment. Magnetic Resonance in Chemistry 2018, 57, 93 -100.

AMA Style

Darcy Fallaise, Hannah Balkwill Tweedie, Julie Konzuk, Carol Cheyne, E. Erin Mack, James G. Longstaffe. Practical application of 1 H benchtop NMR spectroscopy for the characterization of a nonaqueous phase liquid from a contaminated environment. Magnetic Resonance in Chemistry. 2018; 57 (2-3):93-100.

Chicago/Turabian Style

Darcy Fallaise; Hannah Balkwill Tweedie; Julie Konzuk; Carol Cheyne; E. Erin Mack; James G. Longstaffe. 2018. "Practical application of 1 H benchtop NMR spectroscopy for the characterization of a nonaqueous phase liquid from a contaminated environment." Magnetic Resonance in Chemistry 57, no. 2-3: 93-100.

Reference entry
Published: 04 December 2017 in Encyclopedia of Magnetic Resonance
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At present, NMR spectroscopy is used infrequently as an analytical tool during the environmental assessments of contaminated sites. Nevertheless, NMR exhibits many attributes that are complementary to the traditionally employed methods for environmental analysis and, as such, has the potential to provide important information that is often missed during standard environmental assessments. In general, conventional approaches for the characterization of contaminated environments are based on the identification and quantification of targeted contaminants of concern with the primary objective being to assess their levels relative to regulatory guidelines. NMR spectroscopy, in contrast, is useful as a tool for environmental analysis for its ability to provide insight into the type and extent of contamination present in a nontargeted manner, such that both suspected and unsuspected compounds may be identified. This article discusses the use of NMR spectroscopy in the environmental industry to improve our understanding of the distribution of chemical contaminants at sites that are undergoing remedial or monitoring activities.Keywords:environmental NMR;groundwater contamination;nonaqueous phase liquids;environmental pollution;environmental characterization;DOSY NMR;HR-MAS NMR

ACS Style

James G. Longstaffe; Darcy Fallaise. Characterization of Heavily Contaminated Environments Using NMR Spectroscopy. Encyclopedia of Magnetic Resonance 2017, 407 -418.

AMA Style

James G. Longstaffe, Darcy Fallaise. Characterization of Heavily Contaminated Environments Using NMR Spectroscopy. Encyclopedia of Magnetic Resonance. 2017; ():407-418.

Chicago/Turabian Style

James G. Longstaffe; Darcy Fallaise. 2017. "Characterization of Heavily Contaminated Environments Using NMR Spectroscopy." Encyclopedia of Magnetic Resonance , no. : 407-418.

Journal article
Published: 01 February 2016 in Chemosphere
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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.

ACS Style

James G. Longstaffe; Denis Courtier-Murias; Andre J. Simpson. A nuclear magnetic resonance study of the dynamics of organofluorine interactions with a dissolved humic acid. Chemosphere 2016, 145, 307 -313.

AMA Style

James G. Longstaffe, Denis Courtier-Murias, Andre J. Simpson. A nuclear magnetic resonance study of the dynamics of organofluorine interactions with a dissolved humic acid. Chemosphere. 2016; 145 ():307-313.

Chicago/Turabian Style

James G. Longstaffe; Denis Courtier-Murias; Andre J. Simpson. 2016. "A nuclear magnetic resonance study of the dynamics of organofluorine interactions with a dissolved humic acid." Chemosphere 145, no. : 307-313.