NMR spectroscopy of wastewater: A review, case study, and future potential.

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.

Inverse or direct detect experiments and probes: Which are "best" for in-vivo NMR research of C enriched organisms?

In-vivo Nuclear Magnetic Resonance (NMR) spectroscopy is a unique and powerful approach for understanding sublethal toxicity, recovery, and elucidating a contaminant's toxic mode of action. However, magnetic susceptibility distortions caused by the organisms, along with sample complexity, lead to broad and overlapping 1D NMR spectra. As such, 2D NMR in combination with C enrichment (to increase signal) is a requirement for metabolite assignment and monitoring using high field in-vivo flow based NMR.

Optimization of an MMPB Lemieux Oxidation method for the quantitative analysis of microcystins in fish tissue by LC-QTOF MS.

Microcystins are toxic heptapeptides produced by cyanobacteria in marine and freshwater environments. In biological samples such as fish, microcystins can be found in the free form or covalently bound to protein phosphatases type I and II. Total microcystins in fish have been quantified in the past using the Lemieux Oxidation approach, where all toxins are oxidated to a common fragment (2-methyl-3-methoxy-4-phenylbutyric acid, MMPB) regardless of their initial amino acid configuration or form (free or protein bound).

NMR assignment of the in vivo daphnia magna metabolome.

Daphnia (freshwater fleas) are among the most widely used organisms in regulatory aquatic toxicology/ecology, while their recent listing as an NIH model organism is stimulating research for understanding human diseases and processes. Daphnia are small enough to fit inside high field NMR spectrometers and can be kept alive indefinitely using flow systems that deliver food and oxygen. As such, in vivo NMR holds the potential to monitor when/if environmental stress is occurring, understand "why" chemicals are toxic (biochemical pathways impacted and toxic-mode-of-action), and differentiate between a temporary flux response (i.

Targeting the Lowest Concentration of a Toxin That Induces a Detectable Metabolic Response in Living Organisms: Time-Resolved 2D NMR during a Concentration Ramp.

nuclear magnetic resonance (NMR) is a powerful analytical tool for probing complex biological processes inside living organisms. However, due to magnetic susceptibility broadening, which produces broad lines in one-dimensional NMR, H-C two-dimensional (2D) NMR is required for metabolite monitoring . As each 2D experiment is time-consuming, often hours, this limits the temporal resolution over which processes can be monitored.

Understanding the Fate of Environmental Chemicals Inside Living Organisms: NMR-Based C Isotopic Suppression Selects Only the Molecule of Interest within C-Enriched Organisms.

In vivo nuclear magnetic resonance (NMR) is rapidly evolving as a critical tool as it offers real-time metabolic information, which is crucial for delineating complex toxic response pathways in living systems. Organisms such as (water fleas) and (freshwater shrimps) are commonly C-enriched to increase the signal in NMR experiments. A key goal of in vivo NMR is to monitor how molecules (nutrients, contaminants, or drugs) are metabolized.

Metabolic Profiling Using In Vivo High Field Flow NMR.

In vivo NMR (nuclear magnetic resonance) has the potential to monitor and record metabolic flux in close to real time, which is essential for better understanding the toxic mode of action of a contaminant and deciphering complex interconnected stress-induced pathways impacted inside an organism. Here, we describe how to construct and use a simple flow system to keep small aquatic organisms alive inside the NMR spectrometer. In living organisms, magnetic susceptibility distortions lead to severe broadening in conventional NMR.

Selective Amino Acid-Only in Vivo NMR: A Powerful Tool To Follow Stress Processes.

In vivo NMR of small C-enriched aquatic organisms is developing as a powerful tool to detect and explain toxic stress at the biochemical level. Amino acids are a very important category of metabolites for stress detection as they are involved in the vast majority of stress response pathways. As such, they are a useful proxy for stress detection in general, which could then be a trigger for more in-depth analysis of the metabolome.

Focusing on "the important" through targeted NMR experiments: an example of selective C-C bond detection in complex mixtures.

Current research is attempting to address more complex questions than ever before. As such, the need to follow complex processes in intact media and mixtures is becoming commonplace. Here, a targeted NMR experiment is introduced which selectively detects the formation of 13C-12C bonds in mixtures.

1D "Spikelet" Projections from Heteronuclear 2D NMR Data-Permitting 1D Chemometrics While Preserving 2D Dispersion.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the non-targeted metabolomics of intact biofluids and even living organisms. However, spectral overlap can limit the information that can be obtained from 1D 1H NMR. For example, magnetic susceptibility broadening in living organisms prevents any metabolic information being extracted from solution-state 1D 1H NMR.

Development and Application of a Low-Volume Flow System for Solution-State in Vivo NMR.

In vivo nuclear magnetic resonance (NMR) spectroscopy is a particularly powerful technique, since it allows samples to be analyzed in their natural, unaltered state, criteria paramount for living organisms. In this study, a novel continuous low-volume flow system, suitable for in vivo NMR metabolomics studies, is demonstrated. The system allows improved locking, shimming, and water suppression, as well as allowing the use of trace amounts of expensive toxic contaminants or low volumes of precious natural environmental samples as stressors.

In-Vivo NMR Spectroscopy: A Powerful and Complimentary Tool for Understanding Environmental Toxicity.

Part review, part perspective, this article examines the applications and potential of in-vivo Nuclear Magnetic Resonance (NMR) for understanding environmental toxicity. In-vivo NMR can be applied in high field NMR spectrometers using either magic angle spinning based approaches, or flow systems. Solution-state NMR in combination with a flow system provides a low stress approach to monitor dissolved metabolites, while magic angle spinning NMR allows the detection of all components (solutions, gels and solids), albeit with additional stress caused by the rapid sample spinning.