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Nuclear Magnetic Resonance - Science method
Explore the latest questions and answers in Nuclear Magnetic Resonance, and find Nuclear Magnetic Resonance experts.
Questions related to Nuclear Magnetic Resonance
Hi solid-state NMR experts,
What happens to the 1H resonances when a proton exchange starts to take place at the surface of metal oxides? Let's say we have multiple highly resolved 1H resonances in the MAS spectrum of an evacuated metal oxide material. There are basic and acidic hydroxyl functions (terminal, bridging and triply bridging).
If this material is exposed to humidity and rehydroxylation starts to occur, a proton exchange with the acidic OH groups (?) is expected to occur under ambient conditions, isn't it? If yes, what would be the possible effect(s) on the 1H MAS spectrum?
I am coding a solid-state NMR pulse sequence on SIMPON (attached file) but I get this error (error: acq overflow in fid points) that I don't know what it means. Does anyone knows what it means?
I am in need to perform variable temperature NMR for my sample. Kindly let me know any universities which makes the services available for externals.
Thanks
It is not possible to quantitatively assess the hole concentration by using the
((Tc)/(Tc_maxc) = {1 − 82.6(p − 0.16)^2 In other words, the argument of determination of holes concentration] is scientifically incorrect by above formula. the correct determination of holes concentration is from nuclear magnetic resonance (NMR) and angle-resolved photo emission spectroscopy (ARPES) experiments that multi-layered cuprate superconductors have non-uniform hole concentrations in each CuO2 plane.
Is the above statement true? Give answer in the light of above comment please.
Hi guys, I am preparing a presentation on diffusion NMR, where I introduce great names on NMR, such as Hahn, Purcell and Stejskal. I can`t seem to find much information on Dr. John E. Turner Jr (from the Stejskal-Tanner equation).
Does anyone know of his fate and birth year?
Compounds isolated from plant are to be characterized using NMR, FTIR and MS.
I have to acquire NMR spectra of marine sediment so I have very high concentrations of salt. I'm using a cryoprobe on a Bruker 600MHz spectrometer and I'm getting very high 90° pulse durations (˜25us) from pulsecal and I'm worried that they could damage the probe.
I have tried diluting the sample to two times the initial volume and the pulse duration goes down a bit (˜18us) but it's still way higher than the suggested 8us.
Dear ResearchGate Community,
I hope this message finds you all well. My name is Michael G. , and I am a Ph.D. student. We are currently synthesizing the lipid NBD-DPPE and are facing some challenges concerning its purification, NMR sample preparation, and in need of NMR data.
- Purification: We're looking for effective methods to purify NBD-DPPE. Any advice regarding techniques, tips, or even literature recommendations would be greatly appreciated. In particular, we'd like to know details regarding column chromatography (mobile-phase, stationary phase, etc)
- NMR Sample Preparation: We would also appreciate guidance on preparing the NBD-DPPE lipid sample for NMR analysis, including the most suitable solvent system and ideal concentration. We understand that lipids can sometimes present specific challenges in NMR analysis due to their hydrophobic nature and tendency to aggregate, and so any advice on this matter would be highly valuable.
- NMR Data: Lastly, if anyone has NMR data of NBD-DPPE lipid and would be willing to share, this would immensely help us in validating our results and ensuring the accuracy of our product.
Thank you very much for your time and consideration. I look forward to any advice or suggestions the ResearchGate community may have to offer.
Best regards,
Michael G. Ph.D. Student.
4 protons peak may be CH2 near a heteroatom .
How can we employ NMR spectroscopy to determine the molecular weight of polyethylene glycol (PEG)? Is it feasible to use NMR to quantify the number of monomers within the PEG chain?
I checked NMR of commercial PGA NMR and i getting two peaks between 4.9 to 4.8.
It is known that sample conductivity affects pulse durations in 1H NMR experiments. But how does the concentration of NaCl in a sample affects pulse durations in sodium-23 (23Na) NMR experiments? Is it the same effect as with protons?
It would be helpful if some references can be given. Thank you.
Is it possible that the peak intensities of an MTSL-labeled protein+ligand be higher than the peak intensities of the unlabeled protein+ligand in 2D NMR? And what would that mean if it happened?
How can we detect the molecular weight of PEG in NMR? Is it possible to detect the number of monomers in that?
Thanks
I analyzed my polymer sample after polymerization by NMR and GPC. The Mn that I obtained by GPC didn't match with my conversion rate obtained by NMR.
For exemple, for a PEGMA RAFT polymerization I have an average Mn at 20852 and I calculated a conversion rate at 62%. My monomer molecular weight was 500 so, normally I have to have a molecular weight around 31000 for a conversion at 62 (62*500=31000). What is the problem?
Does phosphorus proton coupling exist in solid phosphorus NMR?
how to convert .jdf NMR file to Topspin compatible format?
Hello
I wanted a thesis topic in the field of food grade nanostructured lipid carrier (NLC) to work with NMR, XRD and DSC. Can you make suggestions?
To determine the NMR yield of fluorine containing product, I need to calculate %yield from 19F NMR spectra using trifluoromethylbenzene as reference standard.
Dear community,
I am currently running some solvent suppression experiment on water samples. I first run a one scan 1H experiment to get the ''O1P'' and then implement it in the solvent suppression experiment (''zgpurge'' pulse program). However the water signal appears distorted, it is asymmetrical and most likely unphased (other signals appear completly fine), which results in an inefficient solvent suppression experiment. I tried to overcome the problem by performing a 3D shimming, and adjusting the phasing parameters (Autophase during the lock and calibrated the autophase offset) but the problem persisted.
What could be the origin of the problem ?

When I do an NMR of plain DMSO-d6 I have observed a small hump around 1.2-1.3ppm. It looks like a broad signal and am not sure as to what this signal could be assigned to. I have tried with new NMR solvent, NMR tube and also clean dry used NMR tube. All these have shown the same result. However, 13C signals correspond to DMSO-d6 only and nothing else. Was wondering if any one of the experts have any explanation to this observation, can be very helpful to me. TIA
In a ligand-protein binding 2D NMR study, what does it mean when there is no chemical shifts but there's a decrease in peak intensities and an increase in linewidths?
If the intensity of a peak is lower and/or the linewidth is higher, does it mean the specificity/affinity of the ligand is higher for that residue?
I've done 15N hmqc to determine the interaction between ligand-protein.
There was no chemical shifts in amino acids after adding the ligand. However, the peak heights of almost every residue were decreased in a dose dependent manner.
Could someone tell me what it means please?
To start of I am designing an HVAC system where for a laboratory application utilizing Nuclear Magnetic Resonance operating at 300 MHz.
I am well aware of the helium cooling within nitrogen shell and the liquified gases refilling. However, I'd like to know if it emits heat while operation, if there is an extraordinary environment required for operation by the device.
Thank you in advance.
I have synthesized a Schiff base compound but everytime I do NMR I found an aldehyde peak of intensity 0.20 or 0.25 like that. I have tried column, recrystallization, solvent wash but couldn't get the clean NMR of the final product.
I am looking for a good reference for 1-13C NMR peaks for Beta-hmb (beta-hydroxy beta-methylbutyrate), and alpha-HIC (alpha-hydroxyisocaprate). I have not been able to find a single experimental instance of 1 carbon Beta-HMB, or aplha-HIC; however, this experimental data is important for proving a hypothesis in a paper I am working on.
Hello everyone,
for my research project, I am doing synthesis with polymer (PEG) and I confirm the formation of the product via NMR. But for me, I don't really trust NMR and it cannot confirm me the formation of my product based on:
- esterification of PEG-OH with acid compound (step 1)
- imine formation (schiff base reaction-step 2)
So I tried to do FT-IR to see the peaks of COO and C=N in my second product. And it is still unclear for me. My spectrum are really strange.
For the formation of imine (step 2) I see the shift in NMR, characteristic to the formation of CH=N (literature) but for me I need more data to confirm it.
Furthermore, I have some additional peaks (not supposed to be here) with high content of protons. So I think my product is not pure....
So I have 3 questions:
1) in FT-IR, how can I confirm the conjugation of OH and COOH (ester) in my synthesis 1
2) in FT-IR, how can I confirm the C=N bond (synthesis 2)
2) For impurities in NMR, what are the options to remove it ?
Thanks in advance
Hi, everyone. I am doing CO2 reduction experiments and I wanted to use NMR to detect the liquid products formed. My media is organic (CH3CN). I have seen some similar works by Prof. Kubiak, et al. that use 1H-NMR to detect the liquid products (particularly, formic acid) in CD3CN but the NMR sample requires the addition of Verkade's base. I am not so familiar with this compound. Does anyone know why (1) the peak of formic acid is not visible (supposedly around 8.02 ppm) if you do not add this base, and (2) what happens between the base and formic acid that causes a peak at 8.50 ppm to occur? Thank you so much!
Is it possible to convert a fid file of NMR to any of the following formats - PDB/mmCIF/XML/UCSF
I am running an MD simulation on a protein-protein complex.
After seeing a similar question on research gate, I checked the amino acids rtp file in my force fields folder, and as expected from this error, the HD1 atom was not present in the HSE entry. The atom HD2 is however present in that entry. So I figured replacing the HD1 atoms in my PDB file with HD2 should solve the error.
And it did. For the time being.
To reaffirm, I made changes in Histidine's hydrogen atoms in the PDB file. When I went ahead with the energy minimization step, I got an error that said there's an Infinite Force on an atom. It turns out that the atom was "HD2" of some Histidine in the PDB file.
I saw online that the reason behind this error was due to atom overlap. Hence, just for seeing if that was the case for me, I changed the coordinates of that atom a little bit (this was just for checking, I can't do this for the actual work). When I ran the EM step again, I got the same error, but for a HD2 of a different Histidine molecule. So yes, overlapping of the atoms is the reason for this particular error. I cannot solve it by changing coordinates of all the HD2 atoms of the Histidines. So it all boils down to the main fatal error that I mentioned.
How do I approach this?
1. Changing the atom name (as in HD1 -> HD2 is not working due to the subsequent error)
2. I do not know if I should add the atom HD1 in the HSE entry in the rtp file (I tried this and got several warnings).
3. I cannot (or should I?) use -ignh because mine is not an NMR structure. I have modelled my proteins on Modeller and refined them online.
Any suggestions/solutions will help me a lot. Thank you in advance!
Hi,
i am starting my master thesis And I am doing polymer synthesis following by precipitation method (dissolution in solvent, non solvent precipitation, centrifugation) repeated 2-3 times. I have some impurities in my NMR analysis.
So I want to know if precipitation method in cold ethyl ether is enough to purify a polymer chain ? if yes, it the best procedure to do a good purification through This method?
Example: addition drop by drop is important ? Stirring fast also ?
Is it better than soxhlet extraction ?
Another suestion regarding the purity of final product. Is GPC can confirm the formation of product ? How can I confirm clearly that the reaction work and the product is formed (in complement with NMR) ?
thanks
A reaction of A and B, gives C. the NMR of reaction mixture contain all peaks of A,B,C. I need to calculate yield or percentage conversion of B to C. A has no role . Yield of C need to calculate with respect to B. all have distinguish peaks. On integration, specific peak of C has 1.00 while B has 0.35. both contain 2 hydrogens each. Can I say yield of C is 1/1.35 *100= 74% ? Or is there any other methods to calculate the yield ?
Hello
I wanted a thesis topic in the field of food grade nanostructured lipid carrier (NLC) to work with NMR, XRD and DSC. Can you make suggestions?
Hello everybody,
I am getting output from ORCA program for NMR chemical shifts in the form of Anisotropic and Isotropic shielding in ppm units for both reference and standard(TMS). So, how can I compare these values with experimental chemical shifts of sample? I am attaching here my ORCA output file also.
Thank you.
Shravan B Rathod
I have been studying a dynamic protein and have selectively labelled a cysteine for 19F NMR. This cysteine has two peaks corresponding to a major and minor conformation. On a 500-MHz spectrometer, the relative populations are roughly 4:1. After I switched to a 700-MHz spectrometer, the relative populations are now roughly 2:1. I have confirmed that this is not a one-time fluke. Can a higher operating frequency enhance the minor population with respect to the major population?
Is there an alternative to gNMR for iterative NMR simulation?
Many years ago, I used gNMR to simulate complex spin systems, but it seems gNMR is no longer supported. Do you know of an alternative to the gNMR?
Hello Everyone,
I did an initial test with F19NMR but my peaks in -CF3 part were overlapped.
My sample was a combination of 4 standard solutions of C4F7COOH, C6F11COOH, C8F15COOH and C10F19COOH which was 100uL plus 100 uL of deuterum MeOH and 800 uL of normal MeOH. I applied 400 NeoNMR which has a specific prob for NMR.
My conclusion is that I have to apply higher frequency like 600MHz or 900 MHZ.
Please let me know if you have any ideas to get a clear signal with this method.
I appreciate any assistance.
Faranak
I need to use 27Al NMR for liquid sample and i whant to know if quartz NMR tube have lower backgroud than NMR glass tube.
If someone know how to reduce the bacground noise let me know.
Thanks
Is it possible to suggest a title (Biophysics of food) that includes all three NMR SAXS DSC devices?
Hi all,
Attached below is the proton nmr spectra of biodiesel. The integration value of peak at 5.2 ppm is set to 1. and corresponding all other integration values are obtained. Is that right .
From there. I'm calculating the yield of biodiesel by using integration values at 3.6 and 2.3 ppm.

I can find the NMR information of purplad&aldehyde adduct in . However, it is very hard to find the mass spectrum characterization of the purpald&formaldehyde in literature. Who has the relevant publication? Thanks!
I have prepared some derivatives of the Copper 8-Hydroxyquinoline complex. It has very low solubility in the DMSO, DMF, and CDCl3. In such a scenario, having a paramagnetic Cu2+ in the structure, How to record an NMR spectrum of the Copper 8-Hydroxyquinoline complex and its derivatives?
Hello scientific community,
Although I have a very specific question related to a very specific equipment, I hope that I will find some answers and/or orientations.
I am actually trying to operate a Bruker Prodigy Cryoprobe, but I am facing some technical issues related to the failure of the cooldown process. I cannot achieve it as the system tells that the cooldown is too slow. What could be the reason for this? Are you using this kind of equipment Flawlessly? What is your experience with this kind of cryoprobe? are they reliable, and robust ?
Thank you in advance.
If i take a crude nmr of my reaction mixture containing one reactant and product without adding any internal standard , is it possible to calculate yield of product integrating distinguish peaks of reactant and product?
HI, I've started ti learn using JMRUI to analyse NMR spectroscopy signals. I completely don't know how to use AMARES quantitation or any other type of quantitation. I have to determine the concentration of metabolites in the spectrum derived from the human brain. I have watched tutorials on youtube, but during them, there are used some databases .sv type to make quantitation and I don't where can I find something like that?
I really beg for help
Best regards,
Aleksandra
I need a solvent to be able to take NMR test from my samples PET-PBT blend. I will really appreciate if you can help me. I already tried DMSO, Chloroform, Water, and Ethanol.
I have two small characteristic peaks in the NMR spectrum showing negative integration values. I would appreciate it if you could share your opinion.
Can use D2O peak at 4.7 ppm to align 1H 1D NMR Spectra?
Usually, it provides a singlet at 5.37 ppm in 1H NMR spectroscopy. But i got one NMR with two singlets at 5.21 and 5.44 ppm. Did they belong to CH2of benzoyl benzoate, or could it be something else??? Please shed light on this issue. Thanks
I am trying to prepare Indigo using Baeyer–Drewson method. However, the NMR spectrum in DMSO shows the presence of a side product along with Indigo. How can i purify the material
I am working in a HVAC project that includes a NMR 300, I found out that it cools down by liquid helium or liquid nitrogen so i want to know the amount or the range of heat rejected to the surrounding
Can plz anyone help me to calculate J-coupling constant for the given NMR spectra?
I need to perform NMR of my sample. Please suggest the minimum amount to sample to do NMR.
Hello,
I am trying to analyze the stability of DYBP (2,5-Dimethyl-2,5-di(tert butyl peroxy)hexyne-3). It is 85% and comes dissolved in mineral oil. What technique would work the best apart from NMR? Would GC-MS or HPLC with reverse phase work?
What is the equation for determination of DPn or molecular weight of polybutylene succinate (the polymer was prepared by polycondensation of diol and diacid) from NMR spectroscopy?
TIA
In a 19F-NMR spectrum, the chemical shifts are usually negative. Therefore, does "upfield" become leftward movement towards zero, or does it still refer to rightward movement, but now becoming more negative?
I have a COF solid powder, and I want to get its NMR, I need a good solvent to dissolve the COF. DMSO or THF are suitable solvents for dissolving COFs?
Generally we use such polymer to make the MIP of a template where non-covalent bond is formed rather than the covalent bond which are difficult to breakdown. So without doing NMR how can we the type of bond formation between the template and polymer.
My compounds are not completely soluble in the DMSO-d6, CDCl3, MeOD. I also tried combination of solvents, also I tried 0.1% HCl and heating. Because of the less solubility of compound, the NMR peaks are not as intense as the solvent peaks and I found after heating the compound it is capturing the moisture and showing a sharp peak.
Please help me out to produce the publishable NMR data.
Thank you in advance
While performing DOSY, I noticed something strange that I can't explain:
I performed 2 DOSYs of 2 polymers with exactly the same parameters (pulse sequence, small and big delta, temperature, same solvent (CDCl3)). What puzzles me is that the diffusion coefficient for the residual CHCl3 in the 2D DOSY plots of Mestre (same processing) is extremely different in both spectra (1.6e-04 and 5.4e-05). I am not very experienced with DOSY, but shouldn't these Ds for CHCl3 at least be in the same range?
I am not concerned with finding exact and correct diffusion coefficients, but rather performing mixture analysis, yet this result seems strange and makes the impression that the processing is not very reliable.
I recently analysed NMR data for one of my pure compounds and there was a singlet peak (1H NMR) integrating for 18H. My supervisor has said that no natural product comes with a t-butyl moiety and my compound may be a contaminant or plasticizer. Is it because having two t-butyl groups would be bulky and is biosynthetically not probable?
I'm a beginner in NMR analysis. I want to know how to read the NMR from my attached file.
The elutrap apparatus I need is for electroeluting the RNA from large preparatory polyacrylamide gel for NMR application. The Elutrap is discontinued kindly please let me know if there is an alternative available for india market .
The reviewer asked me "NMR: An external standard should be referred for calibration?" But I did not add external standard (TMS or TSP.) when I made it, may I use heavy water (sample dissolved in heavy water) to locate the residual peak of heavy water solvent (4.71)?
In the structural characterization of polysaccharides, the reviewer asked me a question about nuclear magnetism
“NMR: an external standard should be referred for calibration.?”
what is the meaning of external standard ?
can you help me with the calculation of amine group chitosan as meq? I made deacetylation reaction by NMR I calculated as 94%.
There are some papers using HPLC & NMR for separation and determination, respectively. But I am looking for some other techniques, easy to apply and more available?
Many thanks in advance.
was reading an older textbook (Duddeck) they describe H,C correlated COSY, interpreted as C connected to H. Is this essentially interpreted the same as HSQC and HETCOR?
In most of the textbooks on NMR, we come across the fact that under the 1.4 Tesla external magnetic field, the precession frequency of 1H (proton) is 60 MHz. Can anyone tell why it's always mentioned as 1.4 T instead of 1 T?
Hi everyone, I am trying to assess the drug loading of a small molecule on PEG. I don't find anything in literature. How can I measure (for dosing purposes) how much of the small molecule is actually attached to PEG? I have read that someone did it with NMR integration but I don't see how since I don't know the exact number of hydrogens in the PEG. Does someone have an idea?
I used a 2 M trifluoroacetic acid solution and hydrolyzed the EPS at 100°C for 2 h. How can I distinguish this method hydrolyzed the samples completely? I don't have access to NMR
Is there an effective way to detect oil/lubricant residuals dissolved in an organic solvent. Both qualitative and quantitative measurements are fine. I am looking for more of a bench top method, quick and easy. I know NMR or HPLC are good for detection.
Is it possible to use UV/VIS spectrophotometer or contact angle measurement??
Any other idea would be highly appreciated.
Thanks
Hi,
We are looking for the best method to characterize aliphatic sulfur compounds which are decomposed in a few minutes after dissolving in NMR solvents?
Thanks,
Rohit
Hello Researcher,
I would like to ask a question about crude (1H) NMR product yield calculation?
When we assign product integration and internal standard integration for percentage yield calculation does solvent (DMF. EtOAc and DMSO) which is used for reaction and workup affects percentage yield? Should I need to give a high vacuum before the crude 1H NMR?
Thanks in advance.
I am working on seaweed polysaccharides and I conduct proton and C13 NMR analysis for the characterization of these polymers. So is there any good software that can interpret the NMR signals/peaks? Or atleast any experts who can help with this?