1H Nuclear Magnetic Resonance Spectra Research Articles

Synthesis, docking study, and antitumor evaluation of benzamides and oxadiazole derivatives of 3-phenoxybenzoic acid as VEGFR-2 inhibitors.

Current chemotherapeutic agents have several limitations, including lack of selectivity, the development of undesirable side effects, and chemoresistance. As a result, there is an unmet need for the development of novel small molecules with minimal side effects and the ability to specifically target tumor cells. A new series of 3-phenoxybenzoic acid derivatives, including 1,3,4-oxadiazole derivatives (4a-d) and benzamides derivatives (5a-e) were synthesized; their chemical structures were confirmed by Fourier-transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectra; and various physicochemical properties were determined. The antiproliferative activities of the new derivatives were evaluated by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Three compounds (4b, 4c, and 4d) exhibited cytotoxicity against two of the three cell lines tested, five compounds (3, 4a, 5a, 5b, and 5e) were toxic to one cell line, while two compounds (5c and 5d) were not cytotoxic to any of the three cell lines tested in the current study. Based on docking scores, MTT assay findings, and vascular endothelial growth factor receptor 2 (VEGFR-2) kinase activity data, Compound 4d was selected for further biological investigation. Flow cytometry was used to determine the mode of cell death (apoptosis vs. necrosis) and the effect on cell cycle progression. Compound 4d arrested HepG2 hepatocellular carcinoma cells in the G2/M phase and activated both the intrinsic and extrinsic apoptosis pathways. In conclusion, Compound 4d has shown promising results for future research as a potent VEGFR-2 tyrosine kinase inhibitor.

Rapid simulation of two-dimensional spectra with correlated anisotropic dimensions.

A new algorithm has been developed to simulate two-dimensional (2D) spectra with correlated anisotropic frequencies faster and more accurately than previous methods. The technique uses finite-element numerical integration on the sphere and an interpolation scheme based on the Alderman-Solum-Grant algorithm. This method is particularly useful for numerical calculations of joint probability distribution functions involving quantities with a parametric orientation dependence. The technique's efficiency also allows for practical least-squares fitting of experimental 2D solid-state nuclear magnetic resonance (NMR) datasets. The simulation method is illustrated for select 2D NMR methods, and a least-squares analysis is demonstrated in the extraction of paramagnetic shift and quadrupolar coupling tensors and their relative orientation from the experimental shifting-d echo 2H NMR spectrum of a NiCl2 · 2D2O salt.

Deconvolution and Analysis of the 1H NMR Spectra of Crude Reaction Mixtures.

Nuclear magnetic resonance (NMR) spectroscopy is an important analytical technique in synthetic organic chemistry, but its integration into high-throughput experimentation workflows has been limited by the necessity of manually analyzing the NMR spectra of new chemical entities. Current efforts to automate the analysis of NMR spectra rely on comparisons to databases of reported spectra for known compounds and, therefore, are incompatible with the exploration of new chemical space. By reframing the NMR spectrum of a reaction mixture as a joint probability distribution, we have used Hamiltonian Monte Carlo Markov Chain and density functional theory to fit the predicted NMR spectra to those of crude reaction mixtures. This approach enables the deconvolution and analysis of the spectra of mixtures of compounds without relying on reported spectra. The utility of our approach to analyze crude reaction mixtures is demonstrated with the experimental spectra of reactions that generate a mixture of isomers, such as Wittig olefination and C-H functionalization reactions. The correct identification of compounds in a reaction mixture and their relative concentrations is achieved with a mean absolute error as low as 1%.

1H Nuclear Magnetic Resonance, Infrared, and Chemometrics in Lipid Analysis of Brazilian Edible-Oil-Based Nutraceuticals

Edible oils have commercial and nutritional value due to the presence of essential fatty acids. They can be consumed fresh in the form of capsules known as nutraceuticals. The quality of such products is of interest to the consumer. In this context, this study describes a method based on high-resolution nuclear magnetic resonance (NMR) and Fourier-transform mid-infrared spectroscopic analysis (FTIR), combined with statistical analyses, to differentiate different edible oils used as nutraceuticals in Brazil by fatty acid content. Through the analysis of 1H NMR spectra, the levels of saturated and unsaturated fatty acids in edible oils were characterized and quantified. Statistical analysis of the data confirmed the real distinctions between nutraceutical raw materials, with emphasis on ω-9, ω-6, and ω-3 fatty acids. The analytical approach presented also demonstrates the potential to identify the origin (animal or vegetable) of edible oils used as nutraceuticals.

Preparation and properties of novolac epoxy resins containing polycyclic aromatic hydrocarbons

AbstractTo meet the demands of high‐density and miniaturized integrated circuits, electronic packaging materials need to have excellent properties. One approach to enhance the performance is to design novel structures. In this study, two novolac oligomers containing naphthalene Naphthalene novolac oligomer (NPF) and biphenyl Biphenyl novolac oligomer (LPF) were synthesized and then reacted with epichlorohydrin to synthesize novel novolac epoxy resins containing polycyclic aromatic hydrocarbons (NPF‐EP and LPF‐EP). Their chemical structures were characterized by Fourier transform infrared and 1H nuclear magnetic resonance spectra. Tetrahydromethyl‐1,3‐isobenzofurandione (MeTHPA) was used as curing agent to prepare cured NPF‐EP/MeTHPA and LPF‐EP/MeTHPA thermosets. Both NPF‐EP/MeTHPA and LPF‐EP/MeTHPA exhibited better thermal and mechanical properties compared with novolac epoxy resin (PF‐EP/MeTHPA). In particular, NPF‐EP/MeTHPA presented the highest glass transition temperature of 193°C and LPF‐EP/MeTHPA had excellent mechanical properties, with tensile and flexural strengths of 94 and 151 MPa, respectively. Additionally, the cured NPF‐EP/MeTHPA and LPF‐EP/MeTHPA also exhibit a lower dielectric constant and dielectric loss, and low coefficient of thermal expansion compared with cured PF‐EP/MeTHPA. This investigation provides valuable insights for the manufacturing of high‐performance novolac epoxy resins for application in electronic packaging materials.

Redox-sensitive self-assembling polymer micelles based on oleanolic modified hydroxyethyl starch: Synthesis, characterisation, and oleanolic release

Our study aimed at developing polymer micelles that possess redox sensitivity and excellent controlled release properties. 3,3′-dithiodipropionic acid (DTDPA, Abbreviation in synthetic polymers: SS) was introduced as ROS (Reactive oxygen species)response bond and connecting arm to couple hydroxyethyl starch (HES) with oleanolic acid (OA), resulting in the synthesis of four distinct grafting ratios of HES-SS-OA. FTIR (Fourier Transform infrared spectroscopy) and 1H NMR (1H Nuclear magnetic resonance spectra) were used to verify the triumphant combination of HES-SS-OA. Polymer micelles were found to encapsulate OA in an amorphous form, as indicated by the results of XRD (X-ray diffraction) and DSC (Differential scanning calorimetry). When the OA grafting rate on HES increased from 7.72 % to 11.75 %, the particle size decreased from 297.79 nm to 201.39 nm as the polymer micelles became compact due to enhanced hydrophobicity. In addition, the zeta potential changed from −16.42 mv to −25.78 mv, the PDI (polydispersity index) decreased from 0.3649 to 0.2435, and the critical micelle concentration (CMC) decreased from 0.0955 mg/mL to 0.0123 mg/mL. Results of erythrocyte hemolysis, cytotoxicity and cellular uptake illustrated that HES-SS-OA had excellent biocompatibility and minimal cytotoxicity for AML-12 cells. Disulfide bond breakage of HES-SS-OA in the presence of H2O2 and GSH confirmed the redox sensitivity of the HES-SS-OA micelles and their excellent controlled release properties for OA. These findings suggest that HES-SS-OA can be potentially used in the future as a healthcare drug and medicine for the prevention or adjuvant treatment of inflammation.

Discriminating extra virgin olive oils from common edible oils: Comparable performance of PLS-DA models trained on low-field and high-field 1H NMR data.

Olive oil, derived from the olive tree (Olea europaea L.), is used in cooking, cosmetics, and soap production. Due to its high value, some producers adulterate olive oil with cheaper edible oils or fraudulently mislabel oils as olive to increase profitability. Adulterated products can cause allergic reactions in sensitive individuals and can lack compounds which contribute to the perceived health benefits of olive oil, and its corresponding premium price. There is a need for robust methods to rapidly authenticate olive oils. By utilising machine learning models trained on the nuclear magnetic resonance (NMR) spectra of known olive oil and edible oils, samples can be classified as olive and authenticated. While high-field NMRs are commonly used for their superior resolution and sensitivity, they are generally prohibitively expensive to purchase and operate for routine screening purposes. Low-field benchtop NMR presents an affordable alternative. We compared the predictive performance of partial least squares discrimination analysis (PLS-DA) models trained on low-field 60 MHz benchtop proton (1H) NMR and high-field 400 MHz 1H NMR spectra. The data were acquired from a sample set consisting of 49 extra virgin olive oils (EVOOs) and 45 other edible oils. We demonstrate that PLS-DA models trained on low-field NMR spectra are highly predictive when classifying EVOOs from other oils and perform comparably to those trained on high-field spectra. We demonstrated that variance was primarily driven by regions of the spectra arising from olefinic protons and ester protons from unsaturated fatty acids in models derived from data at both field strengths.

One pot synthetic approach to 2‐methyl‐5‐phenyl‐7‐amino‐[1,3,4]‐thiadiazolo[3,2‐a]pyrimidine‐6‐carbonitrile derivatives with antifungal evaluation

AbstractNovel 2‐methyl‐5‐phenyl‐7‐amino‐[1,3,4]‐thiadiazolo[3,2‐a]pyrimidine‐6‐carbonitrile derivatives 3 were synthesized from 2‐amino‐5‐methyl‐1,3,4‐thiadiazole 1 and benzylidinemalononitrile 2 in ethanol by refluxing the mixture with catalytic amount of NaOH. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1H nuclear magnetic resonance spectra. The newly synthesized compounds were also seen as an affective fungicide against Rhizoctonia solani and Trichoderma sp., two fungal microbes causing diseases in rice plants.

Tear metabolomics for the diagnosis of primary open-angle glaucoma

Primary Open-Angle Glaucoma (POAG) is the most prevalent glaucoma type, and the leading cause of irreversible visual impairment and blindness worldwide. Identification of early POAG biomarkers is of enormous value, as there is not an effective treatment for the glaucomatous optic nerve degeneration (OND). In this pilot study, a metabolomic analysis, by using proton (1H) nuclear magnetic resonance (NMR) spectroscopy was conducted in tears, in order to determine the changes of specific metabolites in the initial glaucoma eyes and to discover potential diagnostic biomarkers. A classification model, based on the metabolomic fingerprint in tears was generated as a non-invasive tool to support the preclinical and clinical POAG diagnosis. 1H NMR spectra were acquired from 30 tear samples corresponding to the POAG group (n = 11) and the control group (n = 19). Data were analysed by multivariate statistics (partial least squares-discriminant analysis: PLS-DA) to determine a model capable of differentiating between groups. The whole data set was split into calibration (65%)/validation (35%), to test the performance and the ability for glaucoma discrimination. The calculated PLS-DA model showed an area under the curve (AUC) of 1, as well as a sensitivity of 100% and a specificity of 83.3% to distinguish POAG group versus control group tear data. This model included 11 metabolites, potential biomarkers of the disease. When comparing the study groups, a decrease in the tear concentration of phenylalanine, phenylacetate, leucine, n-acetylated compounds, formic acid, and uridine, was found in the POAG group. Moreover, an increase in the tear concentration of taurine, glycine, urea, glucose, and unsaturated fatty acids was observed in the POAG group. These results highlight the potential of tear metabolomics by 1H NMR spectroscopy as a non-invasive approach to support early POAG diagnosis and in order to prevent visual loss.

Efficient Quantification of Milk Metabolites from 1H NMR Spectra Using the Signature Mapping (SigMa) Approach: Chemical Shift Library Development for Cows' Milk and Colostrum.

Cow milk contains essential nutrients for humans, and its bulk composition is usually analyzed using Fourier transform infrared spectroscopy. The higher sensitivity of nuclear magnetic resonance (NMR) spectroscopy can augment the extractible qualitative and quantitative information from milk to nearly 60 compounds, enabling us to monitor the health of cows and milk quality. Proton (1H) NMR spectroscopy produces complex spectra that require expert knowledge for identifying and quantifying metabolites. Therefore, an efficient and reproducible methodology is required to transform complex milk 1H NMR spectra into annotated and quantified milk metabolome data. In this study, standard operating procedures for screening the milk metabolome using 1H NMR spectra are developed. A chemical shift library of 63 milk metabolites was established and implemented in the open-access Signature Mapping (SigMa) software. SigMa is a spectral analysis tool that transforms 1H NMR spectra into a quantitative metabolite table. The applicability of the proposed methodology to whole milk, skim milk, and ultrafiltered milk is demonstrated, and the method is tested on ultrafiltered colostrum samples from dairy cows (n = 88) to evaluate whether metabolic changes in colostrum may reflect the metabolic status of cows.

Use of NMR, FTIR and GC–MS to monitor the oxidation products of phospholipids in bighead carp head during cooking process

Bighead carp head soup is a traditional Chinese cuisine with a pleasant aroma, but the effect of fish head phospholipids (FPLs) on the odorants is not fully understood. In this study, nuclear magnetic resonance (NMR), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME–GC–MS) were used to monitor the oxidation products of phospholipids in fish head soup during the cooking process, and the fish head triglycerides (FTGs) were used as controls. In 1H NMR spectra, the signals of unsaturated acyl groups and the oxidation compounds in FPLs were significantly higher than those in FTGs. The results of FTIR showed that the changes of functional group absorptions of the oxidation compounds in FPLs were greater than FTGs. GC–MS demonstrated that FPLs samples produced more lipid-derived volatile compounds than FTGs samples. These results showed that FPLs were more prone to oxidation and could produce more lipid-derived odorants. Therefore, FPLs rather than FTGs, were the main precursor substance of lipid-derived odorants in bighead carp head soup.

N-SALICYLOYL AMIDES AND THEIR SALTS: SYNTHESIS, BIOLOGICAL ACTIVITY AND TOXICITY

The Schotten-Baumann reaction was used to synthesize N-salicyloyl derivatives of Morpholine, Glycine and gamma-aminobutyric acid in the process between salicyloyl chloride with morpholine, glycine or gamma-aminobutyric acid with high yield. Sodium and lithium salts of the salicylamides were synthesized by the reaction of an amide with sodium ethylate or lithium hydroxide in inert solvent. The synthesized compounds were charachterized by 1H nuclear magnetic resonance spectra and elemental analysis. Purity was checked by thin layer chromatography. Quantitative analysis of metal ions was done by potentiometry. To select the most promising compounds exhibiting psychotropic (Pa > 0.8) and antiviral (Pa about 0.5) activities, computer analysis was carried out through the PASS program. In the present study, psychotropic (the open-field exploratory test, the forced swim test, the elevated plus-maze test, the passive avoidance test), analgesic (current vocalization threshold) activities and acute toxicity were evaluated. The results of psychotropic activity revealed that amides possess significant psychotropic activity and low acute toxicity. Disodium salicylurate showed a significant antiamnesic action. The results suggested a significant antidepressant activity and antiamnesic action for dilithium salicylurate and sodium salt of salycyloyl morphlide, a psychostimulant action for lithium salt of salicyloyl morphlide. Lithium gamma-(N-salycylamino)butyrate demonstrated psychostimulant and antiamnesic activities. Our present investigation demonstrated that all compounds are very safe for consumption with high LD50 value. All obtained compounds were evaluated for their antiviral activities against a large number of DNA and RNA viruses including herpes simplex viruses 1 and 2, vaccinia virus, vesicular stomatitis virus, HIV-1 and HIV-2. These compounds were evaluated against human cervix carcinoma cells (HeLa) and CEM T-lymphocytes as well as murine leukemia cells (L1210). The antiviral activity studies depicted that none of the tested compounds were active against DNA or RNA viruses.

Novel Operando Nuclear Magnetic Resonance Approach for Tracking the Electrode State of Charge in Li/Na-Ion Batteries

Lithium and sodium-ion batteries have become the focal point of interest for the energy transition due to their promising applications for electric cars and energy grid storage. Operando characterization of batteries is critical to understand the degradation processes and increasing their electrochemical performance, especially in abusive conditions like during fast charges. Knowledge of the redox state of each electrode is essential to identify the origins of capacity loss in full batteries. Among the methods used for these investigations, operando Nuclear Magnetic Resonance (NMR) methods are promising since, without destroying the battery, they enable monitoring in real-time the electrochemical processes and the formation of short-lived metastable or reactive phases [1,2].Up to now, most operando NMR studies have focused on 7Li NMR spectroscopy to follow the lithiation and degradation processes in the solid electrodes of lithium-ion batteries. However, the large shifts and broadenings of the NMR spectra, which result from the redox-active paramagnetic ions (Ni2/3+, Co4+, Mn3/4+) or from the metallicity of the electrodes [3], complicate operando NMR spectra acquisition and interpretation for full batteries.Herein, we demonstrate that the 1H operando NMR signal of the liquid electrolyte solvent can be used to spy on the positive electrode evolution while benefitting from the high sensitivity of 1H liquid-state NMR compared to 7Li NMR. So far, operando NMR using the liquid electrolyte signal was mainly exploited to follow electrolyte decomposition [4] or to image indirectly dendrite formation [5]. Contrary to the lithium or sodium atoms composing the electrodes, hydrogen atoms in the electrolyte solvent are not a direct probe of the state of charge of the electrode. We demonstrate that the 1H NMR signal of the electrolyte molecules in the battery is, however, highly sensitive to the magnetic susceptibility (and therefore the redox state) of the neighboring particles of positive electrode active material.The state-of-charge (SOC) of the positive electrodes in the charging battery can be tracked indirectly through distortion in the spectrum of the dimethyl carbonate (DMC) solvent near the positive electrode. The effect of the other battery components such as current collectors, separators, or even negative electrodes is shown to be negligible compared to the perturbations induced by the positive electrode. We define specific descriptors to track the changes in the distorted 1H NMR spectrum of the battery and we correlate these changes with the state-of-charge of the positive electrode inside the battery as it is charged and discharged. This approach will enable measuring, operando, the redox state of positive electrodes in batteries, even when their 7Li signals cannot be detected by NMR. Exact knowledge of the redox state will contribute to a better exploitation of the electrochemical curves in full batteries.[1] Bagheri, K.; Deschamps, M.; Salager, E. Nuclear Magnetic Resonance for Interfaces in Rechargeable Batteries. Current Opinion in Colloid & Interface Science 2023, 64, 101675. https://doi.org/10.1016/j.cocis.2022.101675.[2] Liu, X.; Liang, Z.; Xiang, Y.; Lin, M.; Li, Q.; Liu, Z.; Zhong, G.; Fu, R.; Yang, Y. Solid‐State NMR and MRI Spectroscopy for Li/Na Batteries: Materials, Interface, and in Situ Characterization. Advanced Materials 2021, 33 (50), 2005878. https://doi.org/10.1002/adma.202005878.[3] Grey, C. P.; Dupré, N. NMR Studies of Cathode Materials for Lithium-Ion Rechargeable Batteries. Chemical Reviews 2004, 104 (10), 4493–4512. https://doi.org/10.1021/cr020734p.[4] Wiemers-Meyer, S.; Winter, M.; Nowak, S. NMR as a Powerful Tool to Study Lithium Ion Battery Electrolytes. Annual Reports on NMR Spectroscopy 2019, 121–162. https://doi.org/10.1016/bs.arnmr.2018.12.003.[5] Ilott, A. J.; Mohammadi, M.; Chang, H. J.; Grey, C. P.; Jerschow, A. Real-Time 3D Imaging of Microstructure Growth in Battery Cells Using Indirect MRI. Proceedings of the National Academy of Sciences 2016, 113 (39), 10779–10784. https://doi.org/10.1073/pnas.1607903113.

Structural geometry and molecular dynamics by nuclear magnetic resonance of organic-inorganic perovskite [NH3(CH2)6NH3]CuBr4 crystal near phase transition temperature

The structural, thermal, and physical properties of newly developed lead-free hybrid perovskite solar cells are discussed for [NH3(CH2)6NH3]CuBr4. The hybrid material undergoes a phase transition at 269 K (TC), and is thermodynamically stable until approximately 472 K. The crystal structure determined by single-crystal X-ray diffraction is monoclinic and triclinic above and below TC, respectively. The 1H and 13C nuclear magnetic resonance spectra, recorded as a function of the temperature, revealed considerable changes in the 1H chemical shifts of NH3 and the 13C chemical shifts of the carbon atoms close to N as a result of the structural phase transition. The large difference in the activation energy, obtained from the 13C spin-lattice relaxation time above and below TC, also appears to be related to energy transfer changes in 13C. The thermal stabilities of [NH3(CH2)nNH3]CuBr4 (n = 3, 4, and 6) were compared by varying the number of methylene units, and the temperature with 2 % weight loss was shown to decrease as the number of methylene units increases. This in-depth analysis of the physical properties is expected to promote the development and application of lead-free hybrid perovskite solar cells.

Co-Encapsulation of Rhenium and Ruthenium Complexes into the Scaffolds of Metal–Organic Framework to Promote CO2 Reduction

The molecular complexes of Re(4,4′-dcbpy)(CO)3Cl (dcbpy = dicarboxylicacid-2,2’-bipyridyl) and [Ru(dcbpy)3]2+ are co-assembled into UiO-66 scaffolds as structural imperfects for CO2 photocatalytic reduction (named as Re-Ru@U). The prepared catalysts are characterized by XRD, Fourier-Transform infrared (FTIR) spectra, X-ray photoelectron spectra (XPS) and N2 adsorption–desorption isotherms. The intact structure of molecular complexes within the matrix are monitored by 1H nuclear magnetic resonance (NMR) spectra through a totally digesting catalyst. The optical properties are studied via absorption and photoluminescence spectra, and the single-electron reduction in Re and Ru complexes is detected by electron paramagnetic resonance (EPR) spectra. An excellent photocatalytic performance is obtained with steady and sustained CO evolution and a turnover number (TON) value of 15 (11 h). The CO activity irradiating by single wavelength presents the absorption-intensity-dependent changing tendency, where the absorption intensity is superposed by Re and Ru complexes. The two radicals related to Re and Ru, respectively, are simultaneously detected in the Re-Ru@U catalyst. It is suggested that the ReC2 component serves as both a photosensitizer and a catalyst, and the RuC2 component works as an additional photosensitizer to supply the second electron for CO2 reduction. The co-assembling of dual metals Re and Ru in the matrix promotes the electron transfer from the reductive Ru centres to one-electron-reduced Re centres and accounts for the superior activity of CO evolution. Our results demonstrate a strategy to develop the multimetallic catalysts via facile assembling into MOF scaffolds to promote photocatalytic performance.

Richer than previously probed: An application of 1H NMR reveals one hundred metabolites using only fifty microliter serum

The classical approach restricts the detection of metabolites in serum samples by using nuclear magnetic resonance (NMR) spectroscopy; however, the presence of copious proteins and lipoproteins emphasize and necessitate the development of a contemporary, high-throughput tactic. To eliminate the lipoproteins and proteins from sera to engender filtered sera (FS), the study was executed with 50 μl serum obtained from five healthy individuals with 5 years of age difference from 25 to 45 years old and the application of a unique mechanical filter with molecular weight cut-off value of 2KDa. The 10 μl FS from each individual was pooled to make 50 μl final volume filled in a co-axial tube for acquisition of a battery of 1D/2D investigations at 800 MHz NMR spectrometer and the assigned metabolites was confirmed through mass spectrometry as well as by comparing 1H NMR spectra of individual metabolites. This innovative tactic is commissioning to reveal more than 100 metabolites. In contrast to the protein precipitation method, 24 new metabolites were recognized in the present study. The present innovative approach characterizes nucleosides, nitrogenous bases, and volatile metabolites that possibly produce a landmark for the delineation of a comprehensive metabolic profile applicable for detection of the molecular cause of pathogenicity, early-stage disease detection and prognosis, inborn error of metabolism, and forensic investigations exerting the least volume of FS and NMR spectroscopy. The assignment of 100 metabolites using 1H NMR-based FS is described for the first time in the present report.

Determination of self-diffusion coefficients in mixtures with benchtop 13C NMR spectroscopy via polarization transfer.

Nuclear magnetic resonance (NMR) is an established method to determine self-diffusion coefficients in liquids with high precision. The development of benchtop NMR spectrometers makes the method accessible to a wider community. In most cases, 1H NMR spectroscopy is used to determine self-diffusion coefficients due to its high sensitivity. However, especially when using benchtop NMR spectrometers for the investigation of complex mixtures, the signals in 1H NMR spectra can overlap, hindering the precise determination of self-diffusion coefficients. In 13C NMR spectroscopy, the signals of different compounds are generally well resolved. However, the sensitivity of 13C NMR is significantly lower than that of 1H NMR spectroscopy leading to very long measurement times, which makes diffusion coefficient measurements based on 13C NMR practically infeasible with benchtop NMR spectrometers. To circumvent this problem, we have combined two known pulse sequences, one for polarization transfer from 1H to the 13C nuclei (PENDANT) and one for the measurement of diffusion coefficients (PFG). The new method (PENPFG) was used to measure the self-diffusion coefficients of three pure solvents (acetonitrile, ethanol and 1-propanol) as well as in all their binary mixtures and the ternary mixture at various compositions. For comparison, also measurements of the same systems were carried out with a standard PFG-NMR routine on a high-field NMR instrument. The results are in good agreement and show that PENPFG is a useful tool for the measurement of the absolute value of the self-diffusion coefficients in complex liquid mixtures with benchtop NMR spectrometers.

1H NMR Metabolomics on Pigs' Liver Exposed to Antibiotics Administration: An Explorative Study.

An untargeted Nuclear Magnetic Resonance (NMR) spectroscopy-based metabolomics approach was applied as a first attempt to explore the metabolome of pigs treated with antibiotics. The final goal was to investigate the possibility of discriminating between antibiotic-treated (TX group) and untreated pigs (CTRL group), with the further perspective of identifying the authentication tools for antibiotic-free pork supply chains. In particular, 41 samples of pig liver were subjected to a biphasic extraction to recover both the polar and the non-polar metabolites, and the 1H NMR spectroscopy analysis was performed on the two separate extracts. Unsupervised (principal component analysis) and supervised (orthogonal partial least squares discriminant analysis) multivariate statistical analysis of 1H NMR spectra data in the range 0-9 ppm provided metabolomic fingerprinting useful for the discrimination of pig livers based on the antibiotic treatment to which they were exposed. Moreover, within the signature patterns, significant discriminating metabolites were identified among carbohydrates, choline and derivatives, amino acids and some lipid-class molecules. The encouraging findings of this exploratory study showed the feasibility of the untargeted metabolomic approach as a novel strategy in the authentication framework of pork supply chains and open a new horizon for a more in-depth investigation.

Amino acid based ionic liquids for revitalization of sulfated lead anodes

Lead acid batteries (LABs) are currently recycled using hazardous, polluting, and energy intensive procedures. Here we report a novel LAB recycling strategy with hydrophilic amino acid-based ionic liquids (ILs) to dissolve the water-insoluble PbSO4 crystals formed during deleterious hard sulfation at the anodes and then electrodeposit metallic Pb on a new surface. We identified two ILs, [Ch][Ser] and [Ch][Thr] ILs that show dramatic solubility towards PbSO4 at room temperature. [Ch][Ser] IL was successfully used in refurbishing hard sulfated anodes that had lost 99 % of their original capacity into a fresh Pb surface. More than 75 % of the capacity was renewed after a complete treatment on a half-cell. Electrodeposition of Pb from the Pb-[Ch][Ser] complex produced a uniform Pb microstructure. A remarkable 99 % of the IL-dissolved Pb2+ ions was electrodeposited. Furthermore, we solved the first crystal structure of the compound formed between Pb2+ and the amino acid-based IL. Based on 1H Nuclear Magnetic Resonance (NMR) spectrum of PbSO4 dissolved in the [Ch][Ser] IL and single crystal X-ray diffraction (XRD) studies, we discovered that the Pb2+ was coordinated with two [Ser] molecules and displayed a hemidirected five-coordinate geometry. ILs that can selectively dissolve PbSO4 thus hold promise for an environment-friendly alternative recycling paradigm for the LAB industry.

Discovery of Biomarkers for Myogenous Temporomandibular Disorders Through Salivary Metabolomic Profiling: A Pilot Study.

To develop a new approach to provide insights into contributing factors to the etiology and pathogenesis of temporomandibular disorders (TMDs) through discrimination of the salivary metabolomic profiling of patients with TMDs of muscular origin (ie, local myalgia) and healthy individuals. Saliva samples from 19 patients with TMDs of muscular origin (ie, local myalgia) and 39 healthy controls were collected and identified by nuclear magnetic resonance (NMR) spectroscopy. 1H NMR spectra for all samples were acquired using a Bruker Avance-III NMR spectrometer operating at 500 MHz, and data processing was performed in TopSpin, MestreNova, SIMCA, and AMIX softwares for metabolite identification. Eight key metabolites were identified between the healthy controls and patients: L-isoleucine, methylmalonic acid, isopropanolamine, dimethyl sulfone, lactic acid, 4-ethoxyphenylacetic acid, N-acetyl alanine, and D-galactose. The results of this study demonstrate that NMR-based metabolomics coupled with multivariate data analysis is a powerful method for the metabolomic profiling of patients with TMDs of muscular origin (ie, local myalgia).