Thrilled to announce the launch of the NEW Spinsolve ULTRA Benchtop NMR system. The Spinsolve ULTRA has the field homogeneity of a superconducting NMR magnet (0.2 Hz / 6 Hz / 12 Hz) in a compact and robust benchtop unit.
When combined with solvent suppression it allows users to resolve compounds dissolved at sub-millimolar concentrations in protonated solvents, such as water. The example below shows how effective the suppression of the very large water signal is. This enables metabolites at concentrations down to a few hundred micromolars to be detected in an 8 minute measurement.
Please contact us to discuss if Spinsolve ULTRA is useful for your application.
HTBLA Wels is a higher technical vocational college of chemistry in Austria. Here, Dr Harald Baumgartner is responsible for the instrumental analytical laboratory. The lab’s main focus is to teach students the basics of NMR (interpretation of spectra).
Dr Baumgartner says “Compared to the old 60 MHz spectrometer, the Magritek Spinsolve benchtop spectrometer is so much easier to use. It is software-based so collecting and processing data is quite straightforward. As well as 1H spectra, our Spinsolve allows us to measure more complex spectra including 13C-spectra. Even 2-dimensional experiments are now available to the students.”
A college student learns about NMR with the Magritek Spinsolve Carbon at HTLBA Wels in Austria
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: Spectra of procaine (top), paracetamol (bottom), and a 1:1 mixture of both (middle) in D2O.
Part 3 discussed how a matched pair of positive/negative magnetic field gradient pulses can be used to encode spins for their displacement. Although this simple sequence has great value from an educational point of view, it is rarely used in practice due to several drawbacks.
The delay time between the two gradient pulses can be quite long (up to several hundreds of milliseconds or even seconds). During that time the spins acquire additional phase information due to chemical shift evolution. This will make it impossible to phase the spectrum if it contains more than one peak.
During the evolution the magnetisation suffers from T2* relaxation, which can lead to significant signal attenuation.
For this experiment to work, it is extremely important that the two gradient pulses are very well matched in length and amplitude. This is very difficult to achieve with a positive/negative pair.
In 1965, E.O. Stejskal and J.E. Tanner published a famous paper describing an experiment which avoids these issues. It is called the Pulsed Gradient Spin Echo (PGSE) experiment, and I love this experiment because it’s so simple, yet technically very challenging. It is still being used in its original form after being around for half a century. The basic idea is shown in Figure 1.
Figure 1: (a) Schematic diagram of the PGSE pulse sequence. (b) The phase evolution of the spins at different locations along the gradient direction. Note that the 180 degree pulse inverts the phase wrap imposed by the first gradient pulse. The second gradient pulse, which is now identical to the first one in amplitude and length, completely refocuses this phase wrap.
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.
We regularly post testimonials on our blog, where our customers describe how they are using their Spinsolve and comment on their experience using it. We have a number of these user stories now, so we have conveniently compiled them all on a new page ‘What Customers Say‘.
Take a look to see how Spinsolve users all over the world, in teaching and research, are using their Spinsolves.
Serving requests from our followers, we have created a list of selected peer-reviewed publications in which our Spinsolve benchtop NMR spectrometer is featured. Spinsolve is being used for research in topics such as online Reaction Monitoring, Hyperpolarisation, Ultrafast 2D NMR, Residual Dipolar Couplings and Process Control.
Our development team is constantly working on improving performance of the Spinsolve. And as a result the quality of NMR spectra you can obtain with Spinsolve has continued to improve. To show this, we have been updating the NMR spectral examples that are available on this website, and also updating Spinsolve 60 MHz data. So please go to Example NMR Spectra and browse through the page. Hope you find these examples useful!
Dr Jonathan Harburn is a Lecturer in Medicinal Chemistry in the Wolfson Research Institute located in the School of Medicine, Pharmacy and Health at Durham University. Working together with Drs Stuart Cockerill and Jonathan Sellars, Dr Harburn’s research goals are to create clinical drug candidates for the treatment of viruses, bacteria and cancer.
In their research, recent progress has focussed repurposing novel fluorinated drug fragments on known drug scaffolds to develop hit identification. 19F NMR using Spinsolve is one of the most useful tools in confirming fluorinated fragment incorporation with spectra run in 3 minutes. Also, 1H NMR is routinely carried out for identification before further spectral data is acquired on higher field NMR.
Alistair Paterson, a Level 2 MPharm student at Durham University, uses Spinsolve to evaluate his sulfathiazole sample
Dr Alan Kenwright is Reader in Spectroscopy and Manager of the solution-state NMR facility in the Chemistry Department at Durham University. His personal research is focussed on developing and using NMR techniques to solve a range of chemical problems. In choosing to use Magritek’s Spinsolve, Dr Kenwright anticipates it will allow the extension of his work in various areas in ways that he could not otherwise. He plans to use the equipment initially in three areas:
Dr Nicola Rogers is a post doc in the Kenwright group using the Magritek Spinsolve to make relaxation measurements on lanthanide complexes at Durham University. For ease of use, it is mounted on a trolley making it easy to move from lab to lab.
“The first application is in looking at lanthanide complexes of the sort used as contrast agents for MRI” … “being able to do measurements in the relatively low magnetic field (43 MHz) used by Magritek’s Spinsolve is a big advantage for us, particularly as the field it uses it not very different to the field actually used in many hospital MRI scanners. These measurements using the Spinsolve are just starting to appear in the literature.” (reference given at the end of this blog post)