The Spinsolve is not only a perfect tool to teach NMR to Chemistry students, but its performance enables it to be used for serious research. This is evidenced in the published papers from our users. Over the last few months there has been a number of new publications featuring Spinsolve. In this post we will highlight a few of them. Click here for a full comprehensive list of publications.
Two educational papers have been published in Journal of Chemical Education by the group at Heinrich Heine University in Düsseldorf, Germany:
- In the first paper they describe a simple experiment in which undergraduates, who are learning 1H NMR spectroscopy for the first time, investigate natural amino acids, and determine their structure and identity using low-field 1H NMR measurements and simple COSY experiments. These students see and learn the connection between the chemical shift of the αC-proton and the isoelectric point of the amino acid. They engage with the spectroscopic topic by acquiring their own spectra, and processing and interpreting the data.
- The second paper applies Spinsolve NMR to analyse more than 50 self-made sample mixtures with two or three components as well as the two marketed tablet formulations containing acetylsalicylic acid/L-ascorbic acid, or acetylsalicylic acid/paracetamol (acetaminophen)/caffeine.
In the conclusions, the authors state that:
This approach for qualitative and quantitative determination of OTC drugs created an attractive approach for learning NMR spectroscopy in the student lab. The students enjoyed the experiment. Though other mixtures can also be used for teaching the basics in the NMR spectroscopy, pharmacy students find it attractive to use actual drugs for these kinds of experiments. The application of the active components attracts a lot of interest in our students. The experiment was evaluated in the way that the students gave feedback concerning their own experience. While describing their response, they used words (translated here into English) such as “exciting”, “own decision making”, “easier interpretation of the spectra”, and so on.
A more research-focused paper comes from The New Zealand Institute for Plant & Food Research and the Department of Chemistry at the University of Otago and was published in the journal Phytochemical Analysis.
- Here Professor Nigel Perry’s group uses high and low field NMR systems in the characterisation of hops. What was particularly exciting was a conclusion on using Spinsolve: “preliminary results suggest that benchtop NMR spectrometers could be used by hops breeders at field stations for screening hops bitter acid profiles.” You can read this open access paper here.
The use of gradients is demonstrated in a paper published in Chemical Engineering Science by the group at the University of Western Australia.
- By-line Nuclear Magnetic Resonance (NMR) measurements of emulsion droplet size distributions are presented based on pulsed field gradient (PFG) measurements. These are performed on temporarily immobilised samples extracted from a main process stream with corrections applied for any temporal variations in sample composition. The overall methodology is initially applied to pure fluids and then a range of water-in-oil emulsions. It is then demonstrated on an emulsification flow loop in which three commercial demulsifiers are separately applied; significant variation in their performance with respect to increasing emulsion droplet size (and thus emulsion destabilisation) is observed. Finally, a more rapid PFG method, Difftrain, is successfully demonstrated with the measured mean emulsion droplet size being used as the input into standard PID control of applied shear and hence the extent of emulsification. Follow this link to access the paper.
In the conclusions, the authors state that:
NMR measurements of emulsion droplet size distributions have been shown to be both possible and effective in a by-line measurement protocol featuring a benchtop NMR spectrometer of sufficient magnetic field homogeneity that oil and water signals can be readily differentiated based upon chemical shift. Such spectrometers are now commercially available,typically for considerably less than US$100,000.
Hence we have collectively demonstrated that NMR PFG is effective for by-line emulsion characterisation and that it can be effectively integrated into a control loop.
Studying methods of signal enhancement through hyperpolarisation methods is a field where Spinsolve benchtop NMR has been applied by a number of groups:
- At the Memorial Sloan Kettering Cancer Center, the polarization level of hyperpolarized 13C pyruvate was quantified using a 43 MHz Spinsolve Carbon. The 13C labelled pyruvate is then used to image mouse brain metabolism. The full paper in Journal of Magnetic Resonance can be accessed here.
- In a contribution to the Journal of Visual Experiments by the group from the Technical University of Munich, the metabolism of cultivated cells is studied using hyperpolarized 13C-labelled pyruvate. The video of the presentation can be watched here.
- The group at Duke University uses a Spinsolve Nitrogen to measure the relaxation times of 15N-labelled molecules which had been polarized by a modified SABRE method. Follow this link to watch a video illustrating the experiments. The full paper is published in The Journal of Physical Chemistry and can be accessed here.
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