Global NMR Discussion Meetings

2025

  • HSQC/F1-PSYCHE TOCSY NOAH Supersequence for the Analysis of Biofluids

    Aditi Pandey (Centre of BioMedical Research, India)

    Abstract: Accurate metabolite assignment is essential for effective metabolomics research. 2D NMR spectroscopy such as 1H-13C HSQC and 1H-1H TOCSY plays vital role in the identification of metabolites when combined with spectral databases. However, collecting high quality HSQC data from biofluids at natural 13C abundance requires large number of scans and hence NMR time typically of the order of 12-24 hours even at high fields (600-800MHz) with cryogenic probes. Performing further COSY and TOCSY in high resolution mode can result in additional hours. While NOAH (NMR by Ordered Acquisition using 1 H detection) supersequences offer
    time-efficient acquisition by combining multiple experiments in a single pulse sequence using a single recovery delay without sacrificing sensitivity. This is achieved by reusing unused magnetization from one experiment (e.g. HSQC) for subsequent ones (e.g. TOCSY). However due to high complexity of biofluids standard TOCSY spectra often suffers from peak overlap.
    The PSYCHE-TOCSY experiment helps resolve this by generating one sharp peak per resonance, thus minimizing overlap. Thus we want to introduce a novel HSQC+PSYCHE-TOCSY NOAH2 supersequence that combines HSQC with PSYCHE-TOCSY to provide fasterand clearer analysis of complex metabolite mixtures in biofluids.

    1. Marco Schiavina Avatar
      Marco Schiavina

      Hello! Very nice work congratulations!
      I was wondering, in your NOAH-based sequence, how much sensitivity is lost (if any) compared to the two experiments acquired separately? How much time is then saved?
      Thank you very much!

      Reply
      1. Aditi Pandey Avatar
        Aditi Pandey

        Hello Marco, very insightful query indeed!
        Actually when we record a PSYCHE-TOCSY separately at all the same acquisition parameters, there is negligible loss in the sensitivity. Here we have compared it with a regular TOCSY, which is although more sensitive but we are often not able to make full use of it due to the crowded peaks.
        I hope you understand. You can further ask any more queries.
        Thank you!

        Reply
    2. Nicolas Bolik-Coulon Avatar
      Nicolas Bolik-Coulon

      That’s quite impressive!
      How does the resolution of the NOAH sequence compares to the a PSYCHE-TOCSY, as opposed to a regular TOCSY?
      The NOAH TOCSY (pannel D in the 1D and 2D NMR Spectra assignment pannel) seems to show some artifacts at 5ppm in F1. Can you comment on that? Also water suppression seems a lot better, what is the reason?
      How does the signal-to-noise ratio compare between the experiments?

      Thanks!

      Reply
    3. Aditi Pandey Avatar
      Aditi Pandey

      Hello Nicolas, thanks for your kind appreciation.
      The resolution in PSYCHE-TOCSY from NOAH sequence is same as standalone PSYCHE-TOCSY. The artefact is due to some phase problem.
      For water suppression we have used presaturation block before the start of TOCSY sequence and excitation sculpting, placed just before the acquisition in homonuclear module.
      The SNR of the two experiments is very similar.
      I hope this resolves your query. Thank you!

      Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • High-resolution ssNMR study of Collagen Protein in Native Bone under Fast Magic Angle Spinning

    Bijaylaxmi Patra (Centre of Biomedical Research, India)

    LinkedIn: @Bijaylaxmi Patra; X: @BijaylaxmiNMR; Bluesky: @bijaylaxmi.bsky.social‬

    Abstract: Fast magic angle spinning (MAS) is a powerful technique in solid-state nuclear magnetic resonance (ssNMR) spectroscopy that effectively decreases line broadening and enables high-resolution structural study of biological systems. Nevertheless, its utility in probing complex and heterogeneous biomaterials in their native form has been constrained. In this study, we leveraged fast MAS (70KHz) to perform 2D ¹H-detected ¹³C–¹H double cross-polarization (CP) heteronuclear correlation experiments on native bone. This high-resolution method enabled the detection of previously unobserved inter-residue correlations within the aliphatic region of collagen. Additionally, our findings suggest potential π-interactions between aromatic amino acids and spatially proximal anionic or imino acids within the collagen triple helix. Our study paves the way for advanced ¹H-detected heteronuclear correlation experiments under fast MAS to more effectively elucidate the complex and heterogeneous structural organization of other native collagen-rich biological systems.

    1. Marco Schiavina Avatar
      Marco Schiavina

      Hello Patra, nice presentation!
      I was wondering if you can observe the same inter-residue correlation also exploiting other SS-NMR experiments such as the C-C DARR or similar.

      Reply
      1. Bijaylaxmi Patra Avatar
        Bijaylaxmi Patra

        Hi Marco, thanks for showing interest in my work.

        Yes, we may observe the same inter-residue correlations using other ssNMR experiments as well, and our future plans include performing such experiments to obtain ¹³C–¹³C correlations.
        However, as an initial study, we preferred ¹H-detected ¹³C–¹H experiments because they require significantly less experimental time compared to ¹³C–¹³C correlation experiments, especially since the experiments are conducted at natural isotopic abundance.

        Fast MAS techniques have not been widely used to study collagen in native bone due to concerns about friction-induced sample instability during long experimental durations. In our previous study (https://doi.org/10.1002/mrc.5508), we demonstrated the feasibility of acquiring ¹H–¹H correlations. Building on that, we now report ¹³C–¹H correlations, and we believe that ¹³C–¹³C experiments will be even more interesting in future studies.

        Reply
    2. Bijaylaxmi Patra Avatar
      Bijaylaxmi Patra

      Hi Marco, thanks for showing interest in my work.

      Yes, we may observe the same inter-residue correlations using other ssNMR experiments as well, and our future plans include performing such experiments to obtain ¹³C–¹³C correlations.
      However, as an initial study, we preferred ¹H-detected ¹³C–¹H experiments because they require significantly less experimental time compared to ¹³C–¹³C correlation experiments, especially since the experiments are conducted at natural isotopic abundance.

      Fast MAS techniques have not been widely used to study collagen in native bone due to concerns about friction-induced sample instability during long experimental durations. In our previous study (https://doi.org/10.1002/mrc.5508), we demonstrated the feasibility of acquiring ¹H–¹H correlations. Building on that, we now report ¹³C–¹H correlations, and we believe that ¹³C–¹³C experiments will be even more interesting in future studies.

      Reply
    3. Zainab Mustapha Avatar
      Zainab Mustapha

      Very nice presentation. I was just wondering if it would be interesting to study other components of the bone and how they are structured within the bone e.g the lipids.

      Reply
      1. Bijaylaxmi Patra Avatar
        Bijaylaxmi Patra

        Yes, it is indeed very interesting to study other components in bone, as it is rich in various types of molecules within its extracellular matrix.

        Bone is a fascinating biomaterial that my lab has been working on for many years. My seniors have already explored water–lipid interactions (https://doi.org/10.1016/j.ssnmr.2020.101666), water–mineral interactions (https://doi.org/10.1021/acsomega.2c01133), and citrate–collagen interactions within the bone matrix (https://doi.org/10.1021/acs.jpcb.1c01431).

        Specifically, regarding lipids in bone, the major type found in the matrix is triglycerides. Nidhi et al. studied lipids in hydrated, dehydrated, and H₂O–D₂O exchanged bone samples. They found that dehydration and H/D exchange significantly affect the transverse relaxation times (T₂) of triglycerides. These changes reflect alterations in the hydrogen bonding network and the local conformational dynamics of the lipid environment. Dehydration increased the mobility of triglycerides, indicating greater freedom of motion when water is removed. For further insights into other components, I recommend reading this book chapter: https://doi.org/10.1039/9781839165702-00614

        Thank you for your curiosity and engagement with our research.

        Reply
    4. KSHAMA SHARMA Avatar
      KSHAMA SHARMA

      Hi Bijaylakshmi, Thank you for the presentation.

      So if I understood correctly, you just ground the native bone and packed it directly into the rotor? Were there any other steps involved in preparing the sample for the fast MAS experiments?

      Reply
      1. Bijaylaxmi Patra Avatar
        Bijaylaxmi Patra

        Studies have shown that cryogenic grinding can alter the structure and hydration of bone. Therefore, we avoided both cryogenic and mechanical grinding. Instead, we carefully prepared small bone flakes (tiny pieces) using a scalpel and directly packed them into the rotor without any further processing. These flakes retained the structural and morphological features of the native intact bone.

        For further queries, you can refer to our published article: https://doi.org/10.1002/mrc.5508.

        I’m grateful for your interest and curiosity about my work.

        Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • Identifying multiple quantum coherence in ionic liquids

    Yanan Li (New York University, United States)

    LinkedIn: @Yanan Li; X: @YananLi12451

    Abstract: Multiple-quantum NMR spectroscopy has long been employed to selectively isolate specific magnetization components. Here, we combined CRAZED and triple-quantum-filtered (TQF) experiments to investigate multiple quantum coherences in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4). This approach offers detailed insights into the ion dynamics and intermolecular interactions characteristic of ionic liquids.

    1. Kirill Sheberstov Avatar
      Kirill Sheberstov

      Hi, on slide 5, you show the dependence of the signal intensity on the angle θ. Which experimental parameters set up this angle? Another question: how many coupled spins are necessary to have to expect triple quantum coherence? And zero order coherence?

      Reply
      1. Yanan Li Avatar
        Yanan Li

        For the first question,we control the angle θ by adjusting the relative amplitudes of gradients along y and z (Gz, Gy).
        For the second question, triple quantum coherence are required at least three coupled spins (like I1+I2+I3+ or I1-I2-I3-). Zero order coherences are formed with at least 2 spins (like I1+I2- or I1-I2+).

        Reply
    2. Yunfan Qiu Avatar
      Yunfan Qiu

      Yanan,
      Thank you for your presentation. You clearly demonstrated intermolecular contributions to the quantum coherence. Since this is an ionic compound, does the contribution come from the cationic counterpart of BF₄ anion or from other ionic liquid species? Do you expect certain nuclei to contribute more significantly? Looking forward to your insights.

      Reply
    3. Yanan Li Avatar
      Yanan Li

      Thank you for the good question! I would say that the observed intermolecular quantum coherences of 11B likely originate from interactions between the BF4 anion and both neighboring anions and cations (11B-1H, 11B -19F, 11B-11B). It is difficult to draw a conclusion from the standard CRAZED experiments, but I tend to favor 1H due to its higher magnetic separation ratio and natural abundance.

      Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • Expanding Solid-State NMR Frontiers: The 1.2 GHz MAS System at CERM

    Rebecca Calamandrei (CERM, Italy)

    Abstract: The ITACA.SB project (https://www.itaca-sb.it/about/) is dedicated to potentiate the Italian Instruct-ERIC center, CERM/CIRMMP (https://www.cerm.unifi.it/) and significantly enhance structural biology (SB) services at selected laboratories of CNR. By enhancing service capacity and overcoming key access barriers, the project supports high-level life sciences research in Italy, boosts international visibility, and fosters stronger integration with European research infrastructures.
    Within this embodiment, a significant enhancement of the instrumentation at CERM/CIRMMP has enabled the expansion of both solution and solid-state NMR research as well as the biotechnologies instrumentation ranging a broad spectrum of experiment set-up and characterization techniques.
    As part of the infrastructure upgrades supported by ITACA.SB, the 1.2 GHz NMR spectrometer at CERM has been equipped with a 0.7 mm solid-state MAS probe. This high-field system offers exceptional performance for the investigation of solid-phase materials, including protein crystals and, more critically, non-crystalline systems such as amyloid fibrils, membrane proteins, and complex sediments. The implementation of ultra-fast magic angle spinning at 1.2 GHz enables the acquisition of high-resolution, proton-detected spectra, comparable in quality to those obtained in solution-state NMR. This advancement significantly expands the capabilities of solid-state NMR for probing molecular dynamics and intermolecular interactions in challenging biological and material samples.
    As the result of the synergic integration of upgraded infrastructure, targeted user support, and strategic collaboration, ITACA.SB not only strengthens Italy’s contribution to the structural biology landscape but also ensures that CERM/CIRMMP operates as a competitive hub for research, facilitating the alignment within the European Research area.

    1. Marco Schiavina Avatar
      Marco Schiavina

      Hello Rebecca! Nice presentation!
      Among all these beautiful instruments and applications presented here, I was intrigued by the performances of the 1.2 GHz equipped with the 0.7 mm MAS probe.
      Could you please comment about the resolution that can be obtained? How fast can you spin and what nuclear spins can be detected?

      Reply
      1. Rebecca Calamandrei Avatar
        Rebecca Calamandrei

        Hi Marco,
        Thanks for your comment! The 0.7 mm MAS probe is capable of spinning up to 111 kHz and features three channels dedicated to the detection of ¹H, ¹³C, and ¹⁵N. The major benefits of using this type of probe at ultra-high magnetic fields are particularly evident in ¹H-detected spectra, which can achieve a level of resolution comparable to that of solution-state NMR. This enables detailed studies of residue-specific dynamics and protein–ligand interactions. These findings highlight the crucial importance of combining ultra-high magnetic fields with ultra-fast magic angle spinning for the structural and dynamic characterization of biomolecular systems in the solid state.

        Reply
    2. Zainab Mustapha Avatar
      Zainab Mustapha

      Nice presentation. I am curious about the NEO console. Does this mean one can set up two different experiments and both run simultaneously instead of queuing experiments?

      Reply
      1. Rebecca Calamandrei Avatar
        Rebecca Calamandrei

        Thank you for your kind and relevant question. In the novel NEO console, each radiofrequency (RF) channel is equipped with both transmission and reception capabilities. This design effectively allows each channel to operate as an independent spectrometer, with its own RF generation, transmission, and receiver architecture.
        In practice, this enables the implementation of multi-receiver experiments in a user-friendly way. The multiple receiver approach developed at our research infrastructure exploits the recovery delay of one experiment to acquire additional experiments simultaneously (see: [Biophys. J. 2019, 10.1016/j.bpj.2019.05.017]).

        For example, ¹³C- and ¹H-detected experiments can be combined to obtain complementary information on multidomain proteins ([Biomolecules 2022, 10.3390/biom12070929]) or to monitor complex protein–protein interactions in real time ([J. Am. Chem. Soc. 2024, 10.1021/jacs.4c09176]).

        This simultaneous acquisition strategy is a key advantage of the NEO architecture, going beyond traditional queuing of experiments.

        Reply
    3. Nicolas Bolik-Coulon Avatar
      Nicolas Bolik-Coulon

      Nice presentation of the facility!
      Is there any plans to use the 1.2 GHz with a liquid state probe?
      Smaller rotor means less materials. How does the sensitivity of the 0.7mm rotor compares with 1.3/1.9 mm rotors on a GHz for example?

      Reply
      1. Rebecca Calamandrei Avatar
        Rebecca Calamandrei

        Dear Nicolas Bolik-Coulon,
        Thank you for your question. Indeed, we have a 5 mm CP-TXO probe for 13C direct detection that is also routinely used at the 1.2 GHz instrument. The gain in resolution at ultra-high fields is significant not only for solid-state but also for solution-state NMR experiments. This is particularly beneficial when working with biomolecules whose spectra display extensive peak overlap. The combination of ultra-high field and 13C detection helps to partially overcome the spectral crowding typically observed in IDPs and IDRs, as demonstrated in this study: [doi: 10.1038/s41596-023-00921-9]. Moreover, although the amount of sample decreases when moving from larger to smaller rotors, the linewidth also narrows due to a greater averaging of dipolar couplings, resulting in more intense signals. Additionally, the sensitivity loss caused by the reduced sample volume is partially compensated by improved inductive coupling between the coil and the sample, which becomes more efficient as the coil size decreases, as illustrated in this review [doi:10.1021/acs.chemrev.1c00918].

        Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • A Palm-Top time-domain NMR spectrometer for the research laboratory

    Dr. Beau Webber (Lab-Tools Ltd., UK)

    LinkedIn: @Beau Webber

    Abstract: Take this Lab-Tools NMR TD spectrometer down off the shelf, plug it in, insert your sample, and you are up and measuring. Measure, plot and fit your results real-time in any of a number of ways, at the lab bench or from a remote location. This TD NMR spectrometer has been designed as a compact precision tool to measure quantitatively the physical properties of your sample. This TD NMR spectrometer can be used to study liquids, solids, polymers and porous materials. This gives data on sample component masses and molecular movement of the atoms and molecules, which lead to qualities which are variously described as mobility, dynamics, stiffness, viscosity or rigidity. Two NMR probes typically cover a wide range of NMR active nuclei : 1H, 19F, 11B, 7Li, 23Na. If you need variable-temperature, then plug in the Peltier thermo-electrically cooled module. -60C to +80C. This enables a wide range of materials-science measurements, and is also the basis of a thermodynamic NMR Cryoporometry system for measuring pore-sizes from nano-meters to micro-meters. In a hurry ? Or have another experiment or sample to do ? These spectrometers are priced so you can just add more on your research bench.

    1. Dr. Beau Webber Avatar
      Dr. Beau Webber

      Updates on an Even More Compact Precision NMR Spectrometer and a Wider Range V-T Probe, for General Purpose NMR and for NMR Cryoporometric Nano- to Micro-Pore Measurements. J. Beau W. Webber. Micro. 2024; 4(3):509-529. DOI: 10.3390/micro4030032.

      Reply
    2. Riley Hooper Avatar
      Riley Hooper

      Very cool! Are the spectrometers controlled on home-built software, and how much customizability is there in the programming for e.g. playing with pulse sequences or other experimental parameters? Are there any plans to add frequency-domain capabilities?

      Reply
      1. Dr. Beau Webber Avatar
        Dr. Beau Webber

        Hi Riley,
        The software has been written in my lab in an array processing language called Apl. It is multi-tasking, and also handles the graphics, and talks to the RF Gate-Array over an Ethernet.
        New and modified pulse-sequences can be written, and either down-loaded into the firm-ware pulse sequence pipeline, or run in the high-level Apl.
        All the front-panel and menu parameters can be set, or saved / loaded to disc. (Tomorrow we are discussing adding an AI assistant to this.)
        There are some frequency-domain capabilities already built in. However my magnets are not homogeneous enough for resolving 1H spectra yet. But I have captured some low-resolution 19F spectra easily.
        Cheers,
        Beau

        Reply
        1. Riley Hooper Avatar
          Riley Hooper

          Interesting, thanks!

          Reply
    3. Amit Bhattacharya Avatar
      Amit Bhattacharya

      Hi Dr. Webber, impressive work! Could you elaborate on how T1rho measurements correlate with viscosity ?

      Reply
      1. Dr. Beau Webber Avatar
        Dr. Beau Webber

        Thanks Amit,
        We have a preliminary equation, but we are still analysing the results.
        But we believe we may have publishable results, just need to validate them in other well defined systems. This data is only days old.
        Can you please contact me on LinkedIn, and I will let you have more info when we are sure we are happy with the results.
        Cheers, Beau

        Reply
    4. Amit Bhattacharya Avatar
      Amit Bhattacharya

      Thank you Dr. Webber.

      Reply
    5. Raj Chaklashiya Avatar
      Raj Chaklashiya

      Hi Dr. Webber, nice presentation! I am intrigued by the small size of the NMR spectrometer and have a few questions:
      1) How transportable is the spectrometer? I am assuming that its smaller size makes it significantly more mobile than other spectrometers, and perhaps capable of being used “on the field” in certain locations where it would otherwise not be possible for a bigger spectrometer to be used (e.g. near a cave, near a river, etc.)
      2) Up to what magnetic field are you able to reach while maintaining the small spectrometer size?

      Reply
      1. Dr. Beau Webber Avatar
        Dr. Beau Webber

        Hi Raj,
        Yes it is very transportable : It fits into a laptop bag, with the 0.5T 20 MHz 1H magnet, and a regulated 8 hour battery supply.
        Very suitable for mobile use in the field indeed.
        The 0.5T magnet is the highest I yet have – but watch this space !
        Thanks for the interest,
        Beau

        Reply
      2. Dr. Beau Webber Avatar
        Dr. Beau Webber

        Hi Raj,
        Yes it is very transportable : It fits into a laptop bag, with the 0.5T 20 MHz 1H magnet, and a regulated 8 hour battery supply.
        Very suitable for mobile use in the field indeed.
        The this magnet is the highest I yet have – but watch this space !
        Thanks for the interest,

        Reply
        1. Raj Chaklashiya Avatar
          Raj Chaklashiya

          Very cool, thank you! I look forward also to seeing how the highest field usable changes in the future!

          Reply
          1. Dr. Beau Webber Avatar
            Dr. Beau Webber

            If you have a suitable magnet, the MK5 NMR goes up to 120MHz, good enough for 2T 1H.

            Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • Microstructural and Dynamical Characterization of Polymer Electrolytes for Li-ion Batteries Using Advanced Solid-State NMR Techniques 

    Isha Isha (Indian Institute of Science, India)

    Abstract: Solid-state lithium-ion batteries (SSLBs) with lithium metal anodes present significant advantages over conventional liquid electrolyte-based lithium-ion batteries (LIBs), including higher energy densities and improved safety. The flammability of liquid electrolytes and the formation of dendrites at the electrodes are critical safety concerns in traditional LIBs. Furthermore, the energy density of conventional LIBs (200–300 Wh kg⁻¹) is insufficient for long-distance applications in battery-powered devices, and their operational temperature range is limited to -20°C to 60°C.
    Implementing solid electrolytes (SEs) offers a promising solution to these challenges. Solid polymer electrolytes (SPEs) exhibit superior mechanical properties and enhanced safety features. However, the primary limitation of SPEs is their low ionic conductivity, typically around 10-4 Scm-1 under ambient conditions, which remains a significant obstacle to their widespread adoption. Understanding the mechanism of conductivity is a crucial step. Our Research mainly focuses on understanding the conductivity mechanism of the polymer electrolytes. Ionic Conductivity depends on the structure and the dynamics of the polymer backbone, and the Solid-State NMR is the only technique that can probe both the local structure and the dynamics. The microscopic properties of the polymers, such as the local structures, phases, and dynamics significantly influence macroscopic conductivity. Understanding the structure-property relationships is crucial to design SPE(s). SS NMR spectroscopy allows non–invasive characterization with site-specific local structural and dynamical details of materials regardless of their crystallinity. The NMR interactions are susceptible to the local structures and dynamics that have been used to gain insight into ion–dynamics mechanism in SPE(s).

    1. Jonas Koppe Avatar
      Jonas Koppe

      Thank you for the presentation! Could explain the observed isotropic-shift evolution for the various salt concentrations observed in the 1H, 6/7Li, and 19F NMR?

      Reply
    2. Riley Hooper Avatar
      Riley Hooper

      Thanks for your presentation Isha, have you extracted any Li hopping/transport rates from your VT 7Li data?

      Reply
    3. Isha Avatar
      Isha

      Thank you for the question , the shift in the isotropic chemical shift represents the change in the phases when salt is added. In PEO, there are crystalline domains and amorphous domains. When the salt is added to the polymer matrix, there is a reformation of the phases dominating by the amorphous which is indicated by the shoulder peaks.

      Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • UV-Induced PET Depolymerization in m-Cresol Monitored by Time-Resolved Diffusion NMR on a Benchtop Spectrometer

    Farwa Khalid (Insitute of physical chemistry, Polish Academy of Sciences, Poland)

    Abstract: PET (polyethylene terephthalate) is commonly used in bottles, fabrics, and packaging due to its transparency, durability, and mechanical properties. Its extensive use, combined with its natural degradation under sunlight and UV rays, slowly and uncontrollably contributes to environmental pollution [1]. Efforts to address waste PET face challenges in achieving energy-efficient and selective depolymerization through physical sorting or existing chemical methods[2]. The depolymerization of PET in m-cresol under UV light is key to breaking it down into valuable monomers[3].
    This study investigates UV-induced depolymerization of PET in m-cresol, focusing on real-time monitoring with Benchtop NMR. A flow-based experimental setup ensures continuous UV light exposure, while Diffusion NMR provides insights into diffusion properties and molecular size distribution during the process. Real-time diffusion data reveals the depolymerization kinetics, transitioning from high-molecular-weight polymer chains to low-molecular-weight monomers. This method offers valuable insights into the mechanistic pathway of PET depolymerization, potentially improving sustainable plastic waste management.
    References
    [1] F. Cao, L. Wang, R. Zheng, L. Guo, Y. Chen, and X. Qian, “Research and progress of chemical depolymerization of waste PET and high-value application of its depolymerization products,” Nov. 03, 2022, Royal Society of Chemistry. doi: 10.1039/d2ra06499e.
    [2] S. Zhang et al., “Selective depolymerization of PET to monomers from its waste blends and composites at ambient temperature,” Chemical Engineering Journal, vol. 470, Aug. 2023, doi: 10.1016/j.cej.2023.144032.
    [3] S. S. Karim et al., “Model analysis on effect of temperature on the solubility of recycling of Polyethylene Terephthalate (PET) plastic,” Chemosphere, vol. 307, Nov. 2022, doi: 10.1016/j.chemosphere.2022.136050.

    1. Kirill Sheberstov Avatar
      Kirill Sheberstov

      Hi Farwa, I have a question regarding the interpretation of DOSY experiments. In case of signal overlap, under which conditions is it possible to distinguish the two overlapping components? Would a signal display mono or biexponential decay? Thank you.

      Reply
    2. FARWA kHALID Avatar
      FARWA kHALID

      I have used a PGSTE-WET to suppress the solvent signals interfering with the PET peaks. Selecting a gradient strength value where the interfering signal is attenuated and only the desired signal appears. This way, I filter out the solvent peaks in the DOSY spectrum.Also, we are using Tailored fitting Normalization to get the polydispersity index.

      Reply
    3. Blake Wilson Avatar
      Blake Wilson

      Hi Farwa, great presentation. How does the wavelength of UV light influence the results you see?

      Reply
      1. Farwa khalid Avatar
        Farwa khalid

        Hi,
        The wavelength of the UV light greatly affects the photodegradation. I even tried the experiment with 270nm wavelength, but I didn’t see the degradation efficiently, even though this one has high energy, because PET shows maximum absorption closer to 300-320nm due to the aromatic ring and ester group. In 270 nm, I did not see the degradation product (Monomer) peak in the region around 9ppm, as it is shown in 365nm proton NMR spectra in my presentation and also I have calculated the peak area of the polymer peak its almost constant in 270nm.

        Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • Optically Addressable NV Centers for Quantum Sensing

    Amaria Javed (NYU Abu Dhabi, United Arab Emirates)

    Abstract: This talk presents our ongoing work on NV-diamond-based quantum sensing at the Center for Quantum and Topological Systems (CQTS) at NYU Abu Dhabi, with a focus on optical techniques for spin state readout and signal enhancement. Nitrogen-Vacancy (NV) centers in diamond are point defects that serve as atomic-scale quantum sensors, offering remarkable sensitivity to magnetic and electric fields, temperature, and strain. These color centers exhibit spin-dependent fluorescence under green laser excitation, enabling optical initialization and readout of their quantum state even at room temperature.
    At the core of our experimental approach is Optically Detected Magnetic Resonance (ODMR), a technique that uses changes in NV center fluorescence to measure shifts in spin transitions, revealing information about the surrounding environment. We are currently building a custom NV-based sensing setup, which involves laser excitation at 532 nm, microwave control of spin transitions, and efficient fluorescence detection via optical filters and photodetectors.
    Our work aims to optimize the optical alignment, fluorescence collection efficiency, and stability of the system for robust quantum sensing applications. We explore methods to enhance contrast in ODMR spectra, increase sensitivity, and suppress background noise, which are critical for real-time, high-resolution measurements. These efforts lay the foundation for emerging applications in nanoscale magnetometry, bioimaging, materials characterization, and lab-on-a-chip sensing technologies.
    This presentation will give an overview of the NV center’s optical properties, practical design considerations in setting up an ODMR experiment, and the broader role of photonics in quantum sensing.

    1. Yunfan Qiu Avatar
      Yunfan Qiu

      Hi Amaria,
      Thank you for your presentation. What specific object or system do you plan to detect using the NV center through ODMR? I assume it is something spin active, so it can interact with the NV and cause observable changes in the emission? Looking forward to hearing more about your project.

      Reply
    2. Amaria Javed Avatar
      Amaria Javed

      Thank you for your interest! Yes, you’re absolutely right, the NV center is sensitive to spin-active species. In our project, we are focusing on EPR detection using the NV center, specifically targeting unpaired electron spins in external samples. The idea is to use the NV’s spin-dependent photoluminescence and ODMR contrast to detect and characterize these spins at the nanoscale.

      Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • Identification, Quantification, and Isolation of Synthetic Cannabinoids in Forensic Drug Seizures

    Mariana Riccio (Universidade de Brasília, Brasil)

    Abstract: Synthetic cannabinoids represent one of the most diverse classes of emerging psychoactive substances and are frequently seized in forensic operations. These substances, designed to mimic the effects of Δ9-tetrahydrocannabinol (Δ9-THC), exhibit diverse chemical structures, making their identification and quantification challenging using conventional methods. In this context, Nuclear Magnetic Resonance (NMR) spectroscopy has emerged as an advantageous analytical alternative, enabling structural characterization and accurate quantification without the need for commercial reference standards of the analyte itself. This study aimed to identify, quantify, and isolate the synthetic cannabinoids JWH-073, JWH-210, and JWH-250 from samples of plant material seized by the Brazilian Federal Police. For this purpose, gas chromatography-mass spectrometry (GC/MS) was used for the preliminary identification of cannabinoids in the samples, flash chromatography for separation, and NMR spectroscopy for characterization and quantification. The results obtained through NMR allowed for detailed structural characterization and confirmation of the identity of the cannabinoids JWH-073, JWH-210, and JWH-250, whose concentrations in the seized samples were 1.42%, 1.64%, and 0.87% (w/w), respectively. Additionally, purification via flash chromatography enabled the separation of the compounds with purities of 76.1% for JWH-073, 72.7% for JWH-210, and 89.0% for JWH-250. The data obtained demonstrate the efficiency of NMR as an analytical method for the quantification of synthetic cannabinoids, providing a reliable approach for forensic analysis without the need for commercial reference standards.

    1. Chloé Gioiosa Avatar
      Chloé Gioiosa

      Hello Mariana, thank you for the nice presentation!
      I have two questions :
      1. At which magnetic field and with what range of concentration did you do your analysis of the mixture with?
      2. I was wondering if this methodology could be used in the future to discriminate the origin of the seized material based on their cannabinoid composition?

      Reply
      1. Mariana Riccio Avatar
        Mariana Riccio

        Hello! Thank you so much for your kind feedback and for your thoughtful questions!

        1. Magnetic field and concentration range:
        The NMR analyses were performed on a 14.1 T spectrometer (600 MHz for ¹H NMR). For the preparation of the samples, 100 mg of plant material was extracted with 1 mL of CDCl₃, resulting in a crude extract that was directly analyzed. The cannabinoid concentrations within this extract ranged from 1 to 3 mg/mL.

        2. Discriminating the origin of the seized material:
        In an ideal scenario, yes — the cannabinoid composition could potentially be used to discriminate the origin of seized material, but it’d have to be supported by a comprehensive database and chemometric tools.

        In Brazil, for instance, the Federal Police runs a project called PeQui (Perfil Químico das Drogas), which focuses on establishing standardized chemical profiles of seized drugs to support forensic intelligence. This includes the analysis of purity, minor constituents, adulterants, and solvent residues to help identify trafficking routes, distribution patterns, and — when possible — infer geographic origin.

        Reply
        1. Chloé Gioiosa Avatar
          Chloé Gioiosa

          Thank you for your answers!

          Reply
    2. Cory Widdifield Avatar
      Cory Widdifield

      Hello,

      I assume that these samples provided by the police were initially as plants (or plant parts). Could you describe the workup stages (extractions?) that are required to isolate the relevant compounds from the plant? Also, I think you are showing 1H NMR results only. Would adding 13C NMR data be useful to help increase your confidence in assigning the spectra to chemical compounds in the samples?

      Reply
      1. Mariana Riccio Avatar
        Mariana Riccio

        Hello, Cory! Thank you for your interest.

        Yes, the samples provided by the Federal Police were plant materials — specifically herbal mixtures suspected to contain synthetic cannabinoids. Here’s a description of the extraction and isolation process for the enriched samples:

        Extraction and isolation:
        A total of 3.85 g of plant material, previously confirmed by GC/MS to contain a mixture of three synthetic cannabinoids, was extracted with 25 mL of methanol in a Falcon tube. The mixture was vortexed for 5 minutes, sonicated for 1 hour, and then centrifuged. The supernatant was collected, and the whole process was repeated another time under the same conditions. The combined extracts were evaporated at room temperature, yielding 165 mg of dry extract.

        This extract was then subjected to flash chromatography using a Biotage® Isolera One system, with a 10 g normal-phase silica column (25–33 µm). The elution was performed with an hexane/ethyl acetate mixture (95:5), allowing the isolation of enriched fractions of the cannabinoids for further analysis.

        Regarding ¹³C NMR:
        You’re absolutely right — while ¹³C NMR would certainly improve the confidence in compound identification, it was only feasible for the enriched fractions obtained through chromatography. In the crude extract, the analyte concentration was too low (~0.5-2%), and acquiring reliable ¹³C spectra would require prohibitively long acquisition times due to sensitivity limitations.

        Reply
        1. Cory Widdifield Avatar
          Cory Widdifield

          Thank you for your responses.

          Reply
    3. Yunfan Qiu Avatar
      Yunfan Qiu

      Hi Mariana,
      Thank you for your presentation, and I enjoyed it! I have two questions: 1. Have you tried using 2D NMR to further validate the structures of the different isomers? 2. This may not be directly related to the NMR focus of this conference, but have you considered getting crystals to precisely determine the structures? look forward to your thoughts.

      Reply
      1. Mariana Riccio Avatar
        Mariana Riccio

        Hi Yunfan,
        Thank you for your kind words and thoughtful questions!

        1. Regarding the use of 2D NMR: yes, we employed 2D experiments—specifically COSY, HSQC, and HMBC—to support the assignment of chemical shifts and confirm the substitution pattern of the isomers. These correlations were essential to distinguish between JWH-250 and its positional isomer JWH-201.

        2. As for crystallography: although single-crystal X-ray diffraction would certainly provide definitive structural confirmation, we didn’t pursue it in this project. The combination of GC/MS and 1D/2D NMR already provided sufficient information to identify the structures with confidence. Moreover, growing suitable crystals from the isolated fractions would have been particularly challenging, both because of the small amount of material and the need for pure, well-formed single crystals. So considering the analytical goals and the limited sample availability, we prioritized solution-state NMR techniques.

        Best regards,
        Mariana

        Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *

  • The Quantum Gate Recipe: Simulation of Nuclear Magnetic Resonance Pulse Protocols for the CNOT and SWAP Quantum gates

    Lena Aly (New York University Abu Dhabi, UAE)

    LinkedIn: @Lena Aly

    Abstract: In this work, we develop a MATLAB-based simulation model for NMR pulse protocols in weakly coupled spin-½ systems, with a focus on implementing quantum logic gates such as the Controlled-NOT (CNOT) gate. The model connects the unitary matrix representation of quantum gates to experimentally realizable pulse sequences using angular momentum operator formalism. It allows direct evaluation of pulse performance and provides quantitative error estimates for various sequences. The model enables informed comparisons between alternative pulse schemes, and lays the groundwork for future extensions to include advanced techniques such as composite pulses for NMR based quantum information science.

    1. Kirill Sheberstov Avatar
      Kirill Sheberstov

      Hi, what is the classical analogy of the CNOT gate, and what is the main difference between the two?

      Reply
      1. Lena Aly Avatar
        Lena Aly

        Hi!

        The action of the CNOT gate is analogous to the classical XOR operation, and the output of the XOR gate can be thought of as the target qubit in a CNOT. Unlike the XOR, however, the CNOT does not reduce the two qubits into one qubit: the control qubit remains as it is, and the target undergoes the XOR operation. This makes the operation of the CNOT reversible and can be represented by a unitary matrix, as required for all quantum gates.

        It can be more challenging to implement the CNOT gate, though, because it is important to only flip the state of the target qubit without changing the coherence of the states.

        Also, the CNOT is an essential component in implementing quantum entanglement, which is necessary to give quantum computers an advantage over their classical counterparts.

        Reply
    2. Jonas Koppe Avatar
      Jonas Koppe

      Thank you for the presentation. How easily can this expanded to investigate e.g., the Toffoli gate?

      Reply
      1. Lena Aly Avatar
        Lena Aly

        Such an interesting question!

        The current work lays the framework for transforming the desired projection operators in the form of idempotents into realizable pulse sequences and testing them. Since any desired expansions would be unitary, they can also be modeled as idempotents and follow the same logic with a minor modification in the defined Hamiltonian.

        Reply
    3. Raj Chaklashiya Avatar
      Raj Chaklashiya

      Hi Lena, nice presentation! I am curious, what are some examples of those small mistakes that could occur when trying to go from the matrices to the pulse sequences?

      Reply
    4. Lena Aly Avatar
      Lena Aly

      Thank you so much!

      Well, since the process of going from the matrices to pulse sequences includes identifying the desired projection operators, factorizing them to include complex numbers, using idempotent identities to rewrite them as exponents, and then trying to separate the exponents such that each exponent applies only to one axis, many mistakes could happen, especially with signs.

      The one I identified in Price et al 1999 (https://doi.org/10.1006/jmre.1999.1851) using the program was in their application of the identity highlighted in the presentation. It was inconsistent with their choice of axis, which did not end well in the simulation as shown (they should have used U^-1 where they have used U). This also makes sense why their result was different from the one by Volkov and Salikhov 2011 (10.1007/s00723-011-0297-2), although they both used the same mathematical foundation to derive the pulse sequence for the CNOT gate.

      Reply
      1. Raj Chaklashiya Avatar
        Raj Chaklashiya

        Thank you! That is very interesting–it turns out sign mistakes are crucial to avoid for these kinds of calculations!

        Reply

    Leave a Reply

    Your email address will not be published. Required fields are marked *