Blog posts by Bertram

Chemistry Department at Lyon College, Arkansas, uses Spinsolve for research and teaching

July 26th, 2017, by

Dr Irosha Nawarathne is an Assistant Professor in the Chemistry Department at Lyon College, a selective liberal arts institution in rural Arkansas. Her work bridges biomedical research to teaching students the practical use of instrumentation to prepare them for employment and the challenges of the chemical industry. She summarizes her experience with the Spinsolve, which was added to the Chemistry Department in 2015:

Spinsolve has become the most popular among faculty and students of our chemistry program. It is used in organic chemistry, instrumental analysis, and advanced inorganic chemistry laboratories. We plan to extend the usage to other areas too. Students have become very interested in the concept of NMR because of this instrument. Their knowledge of NMR is improved tremendously after the incorporation of Spinsolve in the chemistry program. It is easy to operate, provides quick analysis, and requires very low maintenance. Spinsolve is definitely the best fit for a small college like ours. We formerly had a cryogenic NMR spectrometer at Lyon but the chemistry program has not been able to maintain the instrument in the long term. Spinsolve is low cost and its low maintenance is key for its great fit to Lyon chemistry program. It is also used in recruiting keen students as they get really excited about the instrument and its capabilities during frequent campus tours.

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Ley Group at Cambridge uses Spinsolve Benchtop NMR as part of their flow chemistry and organic synthesis research

June 22nd, 2017, by

Professor Steven Ley’s laboratories are located in the Department of Chemistry at the University of Cambridge. Their research specialises in flow chemistry and organic synthesis. They are renowned for collaborations with academic and industrial partners. Précising their work, Steve says

“Complex synthesis remains a challenging occupation requiring an exceptional level of experimental skill, extensive knowledge of both mechanistic and molecular reactivity, and a bold, inventive, and creative spirit. It is the combination of these qualities that transforms the synthesis process from one of simple logistics to an art form.”

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RIVM in the Netherlands uses the Spinsolve benchtop NMR spectrometer to investigate illegal drugs

June 8th, 2017, by

Dr Peter Keizers is a scientist in the Centre for Health Protection at RIVM, the Dutch National Institute for Public Health and the Environment based in Bilthoven. As a chemist, he investigates (illegal) drugs, medical devices and other medicinal products. His group studies the composition of these products and specifically look for active pharmaceutical ingredients, preferably in a quantitative way.


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New Spinsolve Publications

March 19th, 2017, by

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.

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Stream the Webinar: Thinking Outside the (Benchtop) Box – High-Field NMR Techniques on Benchtop Instruments

October 29th, 2016, by

Did you miss our recent webinar ? No problem, just click the red button below to stream a replay of the webinar held on 27th October 2016: Thinking Outside the (Benchtop) Box – High-Field NMR Techniques on Benchtop Instruments

 




Stream the Webinar Recording



 

In this webinar you will learn about:

  • High-field techniques that are now possible on benchtop instruments.
  • Applications and problems solved by advancements in benchtop NMR spectroscopy.
  • The size, ease-of-use, and economic advantages of benchtop instruments over high-field machines.

In recent years benchtop NMR spectrometers have become an increasingly viable alternative to high-field systems. Many demanding resolution and sensitivity requirements can now be met with modern methods and instruments. In this webinar we illustrate how a number of well-established and modern high-field NMR techniques, such as 2D, non-uniform sampling (NUS), and pure shift experiments, can be implemented on a benchtop NMR system to solve problems and applications previously considered beyond reach.

Benchtop qNMR evaluation

September 18th, 2016, by

In an earlier post on qNMR we described how benchtop NMR can be used to quantify the concentration of a sample or measure its purity. When such quantitative methods are validated, there are standard requirements for accuracy, precision, range, and linearity over that range that need to be met.

For example, the United States Pharmacopeia (USP) specifies the general requirements for a Category I NMR method when measuring a drug substance (there are other specifications for finished products and impurities). These specifications are listed in the table at the end of this post and are compared to the measured Spinsolve performance.

We have validated the Spinsolve benchtop qNMR performance by measuring the purity of one reference standard, methylsulfonylmethane (MSM), with another, maleic acid. Maleic acid is a common reference standard for qNMR, so this was used as the reference to measure the known purity of MSM (specified 99.5% pure). A spectrum of the mixture in D2O is shown in Figure 1.

Spectrum of MSM and maleic acid in D2O

Figure 1: Spectrum of MSM and maleic acid in D2O.

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Quantitative benchtop NMR

September 12th, 2016, by

Quantification using any analytical method requires calibrating an instrumental response with a known reference, and then calculating the concentration of an unknown sample from the measured instrument response. One advantage of NMR compared to other analytical methods is that the signal response is linear, resulting the NMR signal intensity being proportional to the number of nuclei.

Sample concentrations and purities can be easily measured from known peaks once the proportionality constant is calibrated using a reference of known concentration and purity. Such measurement methods are known as quantitative NMR, or qNMR for short.

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Gradients in NMR Spectroscopy – Part 6: Mixture Analysis by Diffusion Ordered Spectroscopy (DOSY)

July 25th, 2016, by

In part 5 we introduced the PGSE experiment to measure self-diffusion coefficients. We saw that if the peak integrals are displayed as a Stejskal-Tanner plot we can immediately identify if there is a single self-diffusion coefficient or not. This works pretty well for neat liquids, or solutions with a single type of molecule, or even polymer molecules with a size distribution. However, in real life we are often dealing with mixtures of molecules, and it would be nice if we could somehow separate the spectra of the individual compounds.

Consider for example the spectrum of a mixture of procaine and paracetamol in D2O. This is shown in the middle scan of Figure 1, along with the spectra of the pure compounds above and below. If we had only the mixture available, but not the pure compounds, it would be hard to figure out how many and which compounds are present in the mixture.

These spectra, along with all the others shown in this post, were acquired on a Spinsolve benchtop NMR spectrometer with additional hardware to enable PFGs for measuring diffusion.

Figure 1

Figure 1: Spectra of procaine (top), paracetamol (bottom), and a 1:1 mixture of both (middle) in D2O.

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About Bertram

Bertram works as Senior Applications Engineer for Magritek in Wellington. He gained his PhD under the supervision of Paul Callaghan and has been working in the field of NMR technology for over 20 years.