With the ZEOtope® product line, neoFroxx now offers first-class deuterated NMR solvents from European production. Together with the Swiss manufacturer, we want to make a large product portfolio of “ZEOtopen” available to our customers. For routine analysis. For research and developement. For industrial synthesis of deuterium-labeled substances. As a source of deuterium for the stabilization of organic molecules.
What is it about?
Nuclear Magnetic Resonance Spectroscopy (NMR) is a non-destructive and non-invasive method for determining the chemical structure and conformation of molecules. It can also provide information about molecular motions and interactions.
The technique is based on the absorption of electromagnetic radiation by atomic nuclei in a strong magnetic field. By applying a high-frequency alternating field, these atomic nuclei are excited and, when they return to their ground state, emit a signal that can be recorded and analyzed.
The applications of NMR spectroscopy are diverse. They include the study of biological (macro)molecules with respect to biochemical processes, the elucidation of reaction mechanisms and chemical structures, the monitoring of chemical reactions, the characterization of polymers, and the determination of impurities in pharmaceutical products.
The rapid further development of NMR instruments is also contributing to an ever broader range of applications and increasing numbers of users. In the past, the technology was limited to heavy high-field devices (> 300 MHz), which could only be installed in special laboratories due to their size and high power requirements. They needed specially trained personnel and large amounts of helium and liquid nitrogen to keep the magnet cool. High-field instruments are still not obsolete, as they achieve the highest resolution and sensitivity. They are mainly used in research. Alternatively, however, compact benchtop NMR devices have been available for several years. Their ease of use, small size and light weight allow NMR spectroscopy to be taken into areas where it was previously not possible. The Benchtop devices are user-friendly and allow quick initial training on the device. The lower magnetic field strength (40 – 100 MHz) and thus lower resolution is not a disadvantage in areas such as quality control, teaching and process control. In these application areas, the advantages of the small devices are more important: Namely, the speed of measurement and data analysis.
NMR = 1H-NMR? Although several NMR active nuclei are available for the technique (1H, 13C,15N, 31P, 23Na and 19F), 1H-NMR (proton NMR) is usually the technique of choice. The reason for this is simply the abundance of NMR-suitable isotopes in the compounds under investigation. Since protons are usually more abundant than carbon atoms, the sensitivity of 1H NMR is several times higher than that of 13C NMR. The same applies to the other NMR variants. Due to the higher sensitivity of 1H NMR, smaller sample volumes and shorter measurement times are sufficient to obtain a good signal-to-noise ratio.
Why deuterated solvents?
An important factor in NMR spectroscopy is the choice of the appropriate solvent. The solvent must dissolve the sample, but not itself generate any signals in the NMR spectrum, nor must it interact with the sample in a way that interferes with the NMR spectrum. There should also be a low viscosity and density difference between the sample and solvent to ensure effective magnetic field homogeneity.
Accordingly, deuterated solvents play an important role in NMR spectroscopy because they improve the sensitivity and resolution of the NMR spectrum and increase the reliability of the measurements. When deuterated solvents are used for NMR spectroscopy, no signal overlaps occur, which can then lead to poorer resolution and interpretation of the spectra.
The use of deuterated solvents also has the advantage of improving the signal-to-noise ratio (SNR). Since deuteration usually results in higher solubility of the sample, a higher concentration of the sample in the solution can be used, resulting in a stronger signal. In addition, the absence of proton signals in the solvent also reduces background noise and thus increases the sensitivity of the measurements.
Even if it is in principle possible to perform NMR spectroscopy without the use of deuterated solvents, the deuterated solvents are a guarantee for high sensitivity and thus for high-quality, easily interpretable and interference-free spectra.
A deuterium atom (2H or D) differs from a “normal” hydrogen atom (1H) by the presence of a neutron in the atomic nucleus. This leads to the fact that the deuterium atom has a slightly different magnetic property than the hydrogen atom, which is reflected in a slightly shifted resonance frequency in the NMR spectrum.
Deuterated solvents - What is important?
An important parameter in NMR solvents is the water content. The water peak can overlay the signal of other compounds in the spectrum and degrade the signal-to-noise ratio. In addition, water can affect the chemical shifts and intensity of NMR signals through interactions with the solvent or solutes. This can lead to shifts or splittings of signals and complicate the analysis of NMR spectra.
For this reason, it is important that deuterated solvents are as dry and free of water as possible. Some data regarding the residual water signals (and the characteristic solvent peaks) can be found in the Tech Note “The-Appearance-of-Solvent-and-Water-Signals-in-1H-and-13C-NMR-Spectra“.
ZEOtope® products are generally characterized by a low residual water content. Further drying prior to application can be carried out with a suitable drying agent (molecular sieve 3Å or 4Å), depending on the solvent. In addition, only NMR tubes that have been specially treated to minimize moisture should be used. The same attention should be given to transfer aids, such as glass pipettes, glass syringes, etc.
It is understood that small sealed containers (single portions, such as the 0.75 ml – ampoule) are not exposed to moisture increase due to storage. The larger the container, the greater the risk of water gain after opening.
Depending on the available sample quantity and the requirement for the measurement result, the choice of isotopic purity is of high importance. In general, the following statement can be made: the higher the field strength (MHz) of the NMR instrument, the higher the isotopic purity of the solvent should be. The chemical purity is closely related to the isotopic purity, since possible impurities are specified by the solvent via the height from the 13C satellite of the (main) residual proton peak.
Why ZEOtope®?
neoFroxx exclusively offers deuterated solvents and deuterated compounds of the ZEOtope® brand. All ZEOtope® products are manufactured in a state-of-the-art production facility in Switzerland. They feature high deuterium enrichment and high chemical purity. Strict quality controls ensure the highest product reliability. The extensive product portfolio ensures that there is the right product for every user.
Well-organized production planning, in-house R&D team for new products and process improvements, continuous investments to adapt capacity to demand, also grant ZEOtope® products an unmatched availability.
ZEOtope® is produced by Zeochem AG, one of the world’s leading manufacturers of deuterium-labeled compounds. With Zeochem, we are supported by an experienced research and development team capable of taking projects from conception to commercialization in quantities ranging from grams to several metric tons.
