Nuclear Magnetic Resonance Tube Research Articles

Direct Observation of Polaritonic Chemistry by Nuclear Magnetic Resonance Spectroscopy

AbstractPolaritonic chemistry is emerging as a powerful approach to modifying the properties and reactivity of molecules and materials. However, probing how the electronics and dynamics of molecular systems change under strong coupling has been challenging due to the narrow range of spectroscopic techniques that can be applied in situ. Here we develop microfluidic optical cavities for vibrational strong coupling (VSC) that are compatible with nuclear magnetic resonance (NMR) spectroscopy using standard liquid NMR tubes. VSC is shown to influence the equilibrium between two conformations of a molecular balance sensitive to London dispersion forces, revealing an apparent change in the equilibrium constant under VSC. In all compounds studied, VSC does not induce detectable changes in chemical shifts, J‐couplings, or spin‐lattice relaxation times. This unexpected finding indicates that VSC does not substantially affect molecular electron density distributions, and in turn has profound implications for the possible mechanisms at play in polaritonic chemistry under VSC and suggests that the emergence of collective behavior is critical.

Direct Observation of Polaritonic Chemistry by Nuclear Magnetic Resonance Spectroscopy.

Polaritonic chemistry is emerging as a powerful approach to modifying the properties and reactivity of molecules and materials. However, probing how the electronics and dynamics of molecular systems change under strong coupling has been challenging due to the narrow range of spectroscopic techniques that can be applied in situ. Here we develop microfluidic optical cavities for vibrational strong coupling (VSC) that are compatible with nuclear magnetic resonance (NMR) spectroscopy using standard liquid NMR tubes. VSC is shown to influence the equilibrium between two conformations of a molecular balance sensitive to London dispersion forces, revealing an apparent change in the equilibrium constant under VSC. In all compounds studied, VSC does not induce detectable changes in chemical shifts, J-couplings, or spin-lattice relaxation times. This unexpected finding indicates that VSC does not substantially affect molecular electron density distributions, and in turn has profound implications for the possible mechanisms at play in polaritonic chemistry under VSC and suggests that the emergence of collective behavior is critical.

The effect of tube quality on externally calibrated quantitative nuclear magnetic resonance analysis: How bad can it be?

Externally calibrated quantitative nuclear magnetic resonance (NMR) approaches offer practical means to simultaneously evaluate chemical identity and content without the addition of calibrants to the test sample. Despite continuous advances in external calibration over the last few decades, adoption of these approaches has been slower than expected. Variations in NMR tube geometry are a commonly overlooked factor that can have a substantial effect on externally calibrated quantitation methods. In this report, we investigate the extent to which tube-to-tube volume variability can affect quantitative NMR outcomes. The results highlight the importance of considering tube quality during the development stages of externally calibrated quantitative methods. In addition, we propose a simple, yet effective volume correction strategy using the residual protonated solvent signal that, based on experiments with mixed NMR tubes of varying quality, alleviates the effect of tube-to-tube variability.

Reconversion of Parahydrogen Gas in Surfactant-Coated Glass NMR Tubes.

The application of parahydrogen gas to enhance the magnetic resonance signals of a diversity of chemical species has increased substantially in the last decade. Parahydrogen is prepared by lowering the temperature of hydrogen gas in the presence of a catalyst; this enriches the para spin isomer beyond its normal abundance of 25% at thermal equilibrium. Indeed, parahydrogen fractions that approach unity can be attained at sufficiently low temperatures. Once enriched, the gas will revert to its normal isomeric ratio over the course of hours or days, depending on the surface chemistry of the storage container. Although parahydrogen enjoys long lifetimes when stored in aluminum cylinders, the reconversion rate is significantly faster in glass containers due to the prevalence of paramagnetic impurities that are present within the glass. This accelerated reconversion is especially relevant for nuclear magnetic resonance (NMR) applications due to the use of glass sample tubes. The work presented here investigates how the parahydrogen reconversion rate is affected by surfactant coatings on the inside surface of valved borosilicate glass NMR sample tubes. Raman spectroscopy was used to monitor changes to the ratio of the (J: 0 → 2) vs. (J: 1 → 3) transitions that are indicative of the para and ortho spin isomers, respectively. Nine different silane and siloxane-based surfactants of varying size and branching structures were examined, and most increased the parahydrogen reconversion time by 1.5×-2× compared with equivalent sample tubes that were not treated with surfactant. This includes expanding the pH2 reconversion time from 280 min in a control sample to 625 min when the same tube is coated with (3-Glycidoxypropyl)trimethoxysilane.

Construction of an active humidity regulation setup for NMR/MRI-Observation and simulation of the controlled evaporation of sessile water droplets

Controlling and improving processes like for example the production of organic semiconductors via printing depends on understanding the interplay of wetting and evaporation of complex fluids. Therefore, examination of the time dependent composition of complex fluid droplets during wetting or evaporation is of interest. The evaporation rate of sessile droplets containing largely water depends on the vapor pressures of the individual components and on the humidity (or partial pressure) of the surrounding gas phase. Hence, for a complete picture of an evaporation process and the comparability of the results of different measurements, it is essential to measure and control the humidity and temperature in the measurement compartment. Accordingly, climate chambers are available in different scales to fit a variety of techniques like contact angle goniometry to obtain results in a controlled atmosphere. We recently reported the application of MRI (Magnetic Resonance Imaging) and spatially resolved NMR (Nuclear Magnetic Resonance) spectroscopy for the examination of the evaporation of sessile droplets on surfaces in 10 mm NMR tubes. These are considered to be closed compartments. Here, we present an apparatus to a) measure and b) control the relative humidity within the sample compartment of the NMR setup by introducing preconditioned gas into the NMR tube. We monitored the evaporation of water droplets using RARE images and compared the volume decay with a) a simple diffusive evaporation model and b) with detailed FEM (finite element numerical model) simulations using COMSOL for validation. We find three evaporation regimes depending on the flow rate as well as on the distance of the gas outlet and the evaporating droplet. In one of the sample configurations tested the evaporation takes place in such a way that it can be described with the help of the simple diffusive model without convection. Thus, the presented approach opens comparative measurements with other methods as well as the observation of droplet evaporation in very dry or very humid environments with and without the influence of convection. Finally, using PRESS spectra, it is shown that the evaporation rate of water from a water/DMSO droplet can be controlled. This shows how the setup presented here can be used to study the evaporation of droplets of more complex mixtures.

Probing Substrate-Loaded Carrier Proteins by Nuclear Magnetic Resonance.

Carrier proteins (CPs) are central actors in nonribosomal peptide synthetases (NRPSs) as they interact with all catalytic domains, and because they covalently hold the substrates and intermediates leading to the final product. Thus, how CPs and their partner domains recognize and engage with each other as a function of CP cargos is paramount to understanding and engineering NRPSs. However, rapid hydrolysis of the labile thioester bonds holding substrates challenges molecular and biophysical studies to determine the molecular mechanisms of domain recognition. In this chapter, we describe a protocol to counteract hydrolysis and study loaded carrier proteins at the atomic level with nuclear magnetic resonance (NMR) spectroscopy. The method relies on loading CPs in situ, with adenylation domains in the NMR tube, to reach substrate-loaded CPs at steady state. We describe controls and experimental readouts necessary to assess the integrity of the sample and maintain loading on CPs. Our approach provides a basis to conduct subsequent NMR experiments and obtain kinetic, thermodynamic, dynamic, and structural parameters of substrate-loaded CPs alone or in the presence of other domains.

Frémy's Salt as a Low-Persistence Hyperpolarization Agent: Efficient Dynamic Nuclear Polarization Plus Rapid Radical Scavenging.

Nuclear magnetic resonance (NMR) spectroscopy is a key technique for molecular structure determination in solution. However, due to its low sensitivity, many efforts have been made to improve signal strengths and reduce the required substrate amounts. In this regard, dissolution dynamic nuclear polarization (DDNP) is a versatile approach as signal enhancements of over 10 000-fold are achievable. Samples are signal-enhanced ex situ by transferring electronic polarization from radicals to nuclear spins before dissolving and shuttling the boosted sample to an NMR spectrometer for detection. However, the applicability of DDNP suffers from one major drawback, namely, paramagnetic relaxation enhancements (PREs) that critically reduce relaxation times due to the codissolved radicals. PREs are the primary source of polarization losses canceling the signal improvements obtained by DNP. We solve this problem by using potassium nitrosodisulfonate (Frémy's salt) as polarization agent (PA), which provides high nuclear spin polarization and allows for rapid scavenging under mild reducing conditions. We demonstrate the potential of Frémy's salt, (i) showing that both 1H and 13C polarization of ∼30% can be achieved and (ii) describing a hybrid sample shuttling system (HySSS) that can be used with any DDNP/NMR combination to remove the PA before NMR detection. This gadget mixes the hyperpolarized solution with a radical scavenger and injects it into an NMR tube, providing, within a few seconds, quantitatively radical-free, highly polarized solutions. The cost efficiency and broad availability of Frémy's salt might facilitate the use of DDNP in many fields of research.

Identification of the novel synthetic cannabinoid-type new psychoactive substance, CH-PIACA, in seized material

Synthetic cannabinoids (SCs) remain the largest class of new psychoactive substances (NPS) according to the European Monitoring Centre for Drugs and Drug Addiction (EMDCDDA) and while the number of new analogues that are reported for the first time each year declines, SCs are reported the most compared to other NPS classes. This decline can be seen as a result of legislative changes by different jurisdictions which have sometimes transitioned to a more generalized approach when controlling substances by defining common structural scaffolds rather than explicit structures. While the consequences of such legislative changes have been expected over the years, the introduction of so called “class-wide” bans has put further pressure on clandestine laboratories to synthesize compounds which are out of the scope of the legislation and thus these compounds are initially harder to detect and/or identify in forensic chemistry or medico-legal contexts in the absence of analytical data. Recently, a synthetic cannabinoid with an indole-3-acetamide core-linker scaffold, AD-18 (i.e. ADB-FUBIATA or ADB-FUBIACA), was reported for the first time in China in 2021. Here, an additional cannabinoid with the indole-3-acetamide scaffold, N-cyclohexyl-2-(1-pentyl-1H-indol-3-yl)acetamide (tentatively CH-PIACA) was structurally characterized using gas chromatography – mass spectrometry (GC-MS), liquid chromatography – high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. A beige powder in a zip-lock bag was seized by The Danish Customs Agency and subsampled by combining three aliquots of approximately 1 g after homogenization with a mortar and pestle. Sample solutions for GC-MS and UHPLC-QTOF-MS were prepared by dissolving the material in methanol and 25% methanol + 1% formic acid, respectively. For NMR, 3 mg of the powder was dissolved in DMSO-d6 and filtered into an NMR tube. Routine GC-MS analysis of the seized material yielded a single major peak at 22.156 min with a molecular ion at m/z 326.3 and fragment ions at m/z 200, 144 and 130 in the electron ionization mass spectrum (EI-MS). In addition, a major component was observed at 11.91 min in the UHPLC-QTOF-MS screening which had a precursor ion at m/z 327.2450 corresponding to a compound with a molecular formula of C21H30N2O. Similar product ions were observed in the electrospray ionization tandem MS (ESI-MS/MS) spectrum with m/z 245.1644, 200.1441, 144.0808, 130.0651, 100.1120 and 83.0853. NMR spectroscopy with 1H, 13 C, COSY, HMBC and HSQC indicated that the structure was likely to be a substituted indole with a pentyl chain and N-cyclohexylacetamide at the 1- and 3 positions. This structure was corroborated by the EI-MS and ESI-MS/MS data with the neutral loss of N-cyclohexyl-carboxamide (C7H13NO, 127.0997 Da) via cleavage of the bond between the α and β carbons forming m/z 200.1441, while the product ion at m/z 245.1644 corresponded to the loss of cyclohexene from the amide nitrogen. The loss of the N-cyclohexyl-carboxamide was also followed by the loss of the pentyl chain from the nitrogen of the indole ring to yield m/z 130.0651, while m/z 100.1120 corresponded to the cyclohexylammonium cation. The product ion at m/z 144.0808 was proposed to be due to the loss of both the N-cyclohexyl-carboxamide and cleavage of the pentyl chain to liberate 1-butene. A new SC with the indole-3-acetamide scaffold was identified in a seized material in Denmark and characterized using GC-MS, UHPLC-QTOF-MS and NMR spectroscopy. This marks the second SC with this scaffold that has been reported with further analogues anticipated to emerge in the near future.

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A Real-Life Reproducibility Assessment for NMR Metabolomics.

Nuclear magnetic resonance (NMR) metabolomics is currently popular enough to attract both specialized and non-specialized NMR groups involving both analytical trained personnel and newcomers, including undergraduate students. Recent interlaboratory studies performed by established NMR metabolomics groups demonstrated high reproducibility of the state-of-the-art NMR equipment and SOPs. There is, however, no assessment of NMR reproducibility when mixing both analytical experts and newcomers. An interlaboratory assessment of NMR quantitation reproducibility was performed using two NMR instruments belonging to different laboratories and involving several operators with different backgrounds and metabolomics expertise for the purpose of assessing the limiting factors for data reproducibility in a multipurpose NMR environment. The variability induced by the operator, automatic pipettes, NMR tubes and NMR instruments was evaluated in order to assess the limiting factors for quantitation reproducibility. The results estimated the expected reproducibility data in a real-life multipurpose NMR laboratory to a maximum 4% variability, demonstrating that the current NMR equipment and SOPs may compensate some of the operator-induced variability.

Perfusion system for studying dynamic metabolomics in rat brain slices exposed to oxygen-glucose deprivation using proton and phosphorus nuclear magnetic resonance.

The aim of the current study was to establish a controlled and reproducible model to study metabolic changes during oxygen-glucose deprivation (OGD) in rat brain using a nuclear magnetic resonance (NMR)-compatible perfusion system. Rat brains were cut into 400-μm thick slices and perfused with artificial cerebrospinal fluid (aCSF) in a 10-mm NMR tube inside a 600-MHz NMR spectrometer. Four experimental conditions were tested: (1) continuous perfusion with aCSF with glucose and normoxia, and (2) 30-, (3) 60-, or (4) 120-min periods of OGD followed by reperfusion of aCSF containing glucose and normoxia. The energetic state of perfused brain slices was measured using phosphorus (31 P) NMR and metabolite changes were measured using proton (1 H) NMR. aCSF samples were collected every 30 min and analyzed using 1 H NMR. The sample temperature was maintained at 36.7±0.1°C and was checked periodically throughout the experiments. Brain slice histology was compared before and after OGD in the perfusion system using hematoxylin-eosin-saffron staining. NMR data clearly distinguished three severity groups (mild, moderate, and severe) after 30, 60, and 120 min of OGD, respectively, compared with the control group. 31 P NMR spectra obtained from controls showed that phosphocreatine levels were stable for 5h inside the perfusion system. Control 1 H NMR spectra showed that lactate, N-acetylaspartic acid, glutamate, γ-aminobutyric acid, and creatine metabolite levels were stable over time, with lactate levels having a tendency to gradually increase due to the recirculation of the aCSF in the perfusion system. A controlled and reproducible perfusion system was established to study the energetic and metabolic changes in rat brain slices during and after OGD of varying severity.

A 3D-Printed Higher-Throughput NMR Tube Cleaner

Nuclear magnetic resonance (NMR) tubes can be cleaned with the proposed device, which can clean five tubes at the same time. It is comprised of a 3D-printed base, polypropylene straws, and a standard vacuum filtration flask assembly. The device is durable, easy to construct and operate, and resistant to common NMR solvents. In our experience, the cleaner saves time and solvent with no drop-off in cleaning efficiency compared to other models. The materials cost of this device is tabulated to be lower than commercially available NMR tube cleaners. The stereolithography and Solidworks files for this device are shared to allow for customization, for cleaning tubes of other dimensions.

An electrochemical cell for in operando 13C nuclear magnetic resonance investigations of carbon dioxide/carbonate processes in aqueous solution.

In operando nuclear magnetic resonance (NMR) spectroscopy is one method for the online investigation of electrochemical systems and reactions. It allows for real-time observations of the formation of products and intermediates, and it grants insights into the interactions of substrates and catalysts. An in operando NMR setup for the investigation of the electrolytic reduction of at silver electrodes has been developed. The electrolysis cell consists of a three-electrode setup using a working electrode of pristine silver, a chlorinated silver wire as the reference electrode, and a graphite counter electrode. The setup can be adjusted for the use of different electrode materials and fits inside a 5 mm NMR tube. Additionally, a shielding setup was employed to minimize noise caused by interference of external radio frequency (RF) waves with the conductive components of the setup. The electrochemical performance of the in operando electrolysis setup is compared with a standard electrolysis cell. The small cell geometry impedes the release of gaseous products, and thus it is primarily suited for current densities below 1 mA cm. The effect of conductive components on CNMR experiments was studied using a -saturated solution of aqueous bicarbonate electrolyte. Despite the field distortions caused by the electrodes, a proper shimming could be attained, and line widths of ca. 1 Hz were achieved. This enables investigations in the sub-Hertz range by NMR spectroscopy. High-resolution CNMR and relaxation time measurements proved to be sensitive to changes in the sample. It was found that the dynamics of the bicarbonate electrolyte varies not only due to interactions with the silver electrode, which leads to the formation of an electrical double layer and catalyzes the exchange reaction between and , but also due to interactions with the electrochemical setup. This highlights the necessity of a step-by-step experiment design for a mechanistic understanding of processes occurring during electrochemical reduction.

Simple and Rapid (Extraction) Protocol for NMR Metabolomics-Direct Measurement of Hydrophilic and Hydrophobic Metabolites Using Slice Selection.

Investigating the metabolic profiles of solid sample materials with solution nuclear magnetic resonance (NMR) spectroscopy requires the extraction of these metabolites. This is commonly done by using two immiscible solvents such as water and chloroform for extraction. Subsequent solvent removal makes these extraction procedures very time-consuming. To shorten the preparation time of the NMR sample, the following protocol is proposed: the metabolites from a solid or liquid sample are extracted directly in the NMR tube, the NMR tube is centrifuged, and the metabolite profiles in the aqueous and organic phases are determined by using slice-selective proton NMR experiments. This protocol was tested with 11 black teas and 11 green teas, which can be easily distinguished by their metabolic profiles in the aqueous phase. As a test case for liquid samples, 29 milk samples were investigated. The geographical origin of the diaries where the milk was processed could not be determined unequivocally from the metabolic profiles of the hydrophilic metabolites; however, this was easily seen in the lipid profiles. As shown for the different test samples, the extraction protocol in combination with slice-selection NMR experiments is suitable for metabolic investigations. Because samples are rapidly processed, this approach can be used to explore different extraction strategies for metabolite isolation.

Selective, Catalytic Oxidations of C–H Bonds in Polyethylenes Produce Functional Materials with Enhanced Adhesion

Summary The synthesis of functional and processable polyethylenes from simple vinyl monomers with controlled molecular weights and architectures has been a grand challenge of polymer chemistry. Post-polymerization modification of the homopolymers of ethylene is attractive for this purpose but has been hampered by the lack of efficient methods for the selective functionalization of C–H bonds in polyolefins. We report the selective, catalytic oxidation of C–H bonds in commodity polyethylenes with varying molecular weights and architectures. Remarkably, the functionalized materials, even at low levels of functionalization, exhibit physical properties that are absent in unmodified polyolefins, such as strong adhesion and the ability to be painted with common waterborne latex paint. Such observations indicate that selectively modified polyethylenes as described here may help to transform existing commodity plastics into more valuable and potentially more sustainable materials.

Application of the New 400 MHz High-Temperature Superconducting (HTS) Power-Driven Magnet NMR Technology for Online Reaction Monitoring: Proof of Concept with a Ring-Closing Metathesis (RCM) Reaction

Monitoring chemical reactions by nuclear magnetic resonance (NMR) is an established and valuable approach for process understanding, robustness, scalability, and control in the pharmaceutical industry. Understanding speciation, reaction rates, and reaction completion times provides information on how to improve a chemical process, leading to increased quality and quantity of the desired product. An important consideration for online monitoring is to have an NMR instrument colocated with a chemical reactor. The standard commercial medium- to high-field NMR instruments are normally installed in isolated locations due to facility and safety restrictions. Low-field NMR instruments suffer from low resolution and sensitivity, requiring chemometric analysis for medium to complex chemical structures. Reactions are typically monitored using NMR tubes and deuterated solvents. Therefore, reaction analysis may not provide the same kinetic information as when the reaction occurs in a reactor at a larger scale. To overcome these factors, we have tested a prototype NMR instrument with a 400 MHz cryogen-free power-driven high-temperature superconducting (HTS) magnet installed in a chemistry laboratory fume hood for online monitoring of reactions. We have tested the HTS NMR system with a ring-closing metathesis (RCM) reaction of diethyl diallyl malonate with Grubbs 2nd Gen catalyst in a reactor with a protonated solvent. The reaction was monitored online with a Bruker InsightMR flow cell, and data was acquired in automation, yielding a kinetic time-course of the transformation and reaction rate values. This work demonstrates that NMR instruments with HTS magnets can be integrated into the chemistry laboratory with other equipment and are a valuable tool for reaction monitoring under typical reaction conditions and in protonated solvents.

Multifrequency Nuclear Magnetic Resonance as an Efficient Tool To Investigate Heterospin Complexes in Solutions.

We report a multifrequency nuclear magnetic resonance (NMR) study of heterospin complexes [Eu(SQ)3Ln], where SQ is 3,6-di(tert-butyl)-1,2-semiquinone, L is tetrahydrofuran (THF), pyridine (Py), or 2,2'-dipyridyl (Dipy), and n is the number of diamagnetic ligands. Multifrequency NMR experiments allowed us to determine the effective paramagnetic shifts of the ligands (L = THF or Py) and the chemical equilibrium constant for [Eu(SQ)3(THF)2]. In addition, we have found a strong magnetic field effect on the NMR line broadening, giving rise to very broad NMR lines at high magnetic fields. We attribute this effect to broadening under fast exchange conditions when the NMR spectrum represents a homogeneously broadened line with a width proportional to the square of the NMR frequency difference of the free and bound forms of L. Consequently, the line width strongly increases with the magnetic field. This broadening effect allows one to determine relevant kinetic parameters, i.e., the effective exchange time. The strong broadening effect allows one to exploit the [Eu(SQ)3(THF)2] complex as an efficient shift reagent, which not only shifts unwanted NMR signals but also broadens them, notably, in high-field NMR experiments. We have also found that [Eu(SQ)3Dipy] is a thermodynamically stable complex; hence, one can study [Eu(SQ)3Dipy] solutions without special precautions. We report an X-ray structure of the [Eu(SQ)3Dipy]·C6D6 crystals that have been grown directly in an NMR tube. This shows that multifrequency NMR investigations of heterospin compound solutions not only provide thermodynamic and kinetic data for heterospin species but also can be useful for the rational design of stable heterospin complexes and optimization of synthetic approaches.

The Development of Cleaning Methods for Liquid Nuclear Magnetic Resonance Tubes

The Development of Cleaning Methods for Liquid Nuclear Magnetic Resonance Tubes

Modeling and Observer-Based Monitoring of RAFT Homopolymerization Reactions

Reversible addition–fragmentation chain–transfer (RAFT) polymerization of methyl methacrylate (MMA) is modeled and monitored using a multi-rate multi-delay observer in this work. First, to fit the RAFT reaction rate coefficients and the initiator efficiency in the model, in situ 1 H nuclear magnetic resonance (NMR) experimental data from small-scale (<2 mL) NMR tube reactions is obtained and a least squares optimization is performed. 1 H NMR and size exclusion chromatography (SEC) experimental data from large-scale (>400 mL) reflux reactions is then used to validate the fitted model. The fitted model accurately predicts the polymer properties of the large-scale reactions with slight discordance at late reaction times. Based on the fitted model, a multi-rate multi-delay observer coupled with an inter-sample predictor and dead time compensator is designed, to account for the asynchronous multi-rate measurements with non-constant delays. The multi-rate multi-delay observer shows perfect convergence after a few sampling times when tested against the fitted model, and is in fair agreement with the real data at late reaction times when implemented based on the experimental measurements.

Electrochemical NMR spectroscopy: Electrode construction and magnetic sample stirring

The use of nuclear magnetic resonance (NMR) spectroscopy to study electrochemical reactions in situ (EC-NMR), in solution, was demonstrated more than four decades ago. Although, the immense potential of EC-NMR has been demonstrated in several applications, this method has been limited to a few specialized groups since there are no commercial EC-NMR cells or cells that can be easily assembled for routine measurements. In most of the proposed EC-NMR cells the electrodes are placed inside the NMR coil, which deteriorates the magnetic field homogeneity and reduces the signal-to-noise ratio. To minimize these interferences, electrochemical cells have been constructed as flow cells, using ultra thin metallic films as electrodes, which are too complex to be produced by non-experts, or use non-metallic electrodes that have limited electrochemical applications. In this paper we report a very simple and efficient way to construct an EC-NMR cell using standard Pt and Ag wires as electrodes. These wires are assembled as coils on capillaries and are inserted into 5 mm NMR tubes and placed approximately 0.5 mm above the NMR coil. During the in situ EC-NMR reaction the magnetohydrodynamic effect stirs the solution, homogenizing the concentration of the reagent and the product in the NMR detection region. This effect allows the concentration of the analyte to be measured in real time, even with the electrodes outside the NMR detection region. The electrode materials are not limited to Pt or Ag wires and can be replaced by other materials according to the studied reaction. Details showing how to make the electrodes are presented in a video in the supplementary material. The application and performance of this cell were demonstrated with an in situ EC-NMR study of the electro-oxidation of ascorbic acid in solution. In this particular case the magnetic field increased the reaction rate by a factor of approximately two.