Probes

HRMAS NMR Probes

Bruker's HRMAS Probes enable high-resolution experiments on colloidal systems and semi-solids. They are ideal to record NMR spectra of samples where different physical phases coexist.

 

High Resolution Magic Angle Spinning (HRMAS) is an established technique for analyzing inhomogeneous and semi-solid samples. With standard solution-state NMR techniques, the spectra of such samples would suffer from broad and unresolved resonances. By spinning at the magic angle (54.7°), line broadening effects due to magnetic susceptibility differences and dipolar interactions within the sample are removed, enhancing spectral resolution, and enabling detailed analysis of the individual components within the sample. HRMAS is the ideal technique to investigate many important classes of samples, such as gels, emulsions, foodstuffs, insoluble polymers, or biological tissues.

Figure 1: Bruker’s HRMAS iProbes are equipped with a deuterium lock channel and a gradient.

Technical Details

Bruker's HRMAS probes are equipped with a gradient coil oriented along the magic angle and a deuterium lock channel. The gradient has been optimized for durability and makes a wide variety of NMR techniques accessible, including gradient enhanced solvent suppression and artefact-free homonuclear and heteronuclear 2D experiments. The tunable deuterium lock channel provides excellent frequency stability over long acquisition times.

Built upon the renowned iProbe platform, Bruker’s HRMAS NMR probes combine innovation, ease-of-use, and reliability. Bruker’s HRMAS iProbes feature integrated automatic tuning and matching, automatic magic angle adjustment, and are compatible with hardware for automatic sample changes. The HRMAS iProbe, shown in Figure 1, is available as a dual channel probe, where the high frequency channel is tunable to 1H and 19F, and the second channel covers a wide frequency range from 31P to 15N. The robust RF design makes it possible to decouple for long times, both on the X and 1H channel, allowing a high resolution in both dimensions even under heteronuclear decoupling.

Bruker’s HRMAS iProbes are available for standard bore (SB) magnets and are compatible with wide bore (WB) magnets. The probes are available for 4 mm rotors, capable of a maximum spinning speed of 15 kHz. Disposable rotor inserts are available for easy sample preparation and clean up.

Bruker's HRMAS probes support direct excitation solid-state NMR experiments. With the combination of high-resolution experiments and solid-state NMR capabilities, these probes offer an attractive solution for a wide range of research needs.

Applications

Examples for typical application of HRMAS NMR are shown below.

In medical applications, HRMAS is often applied as a nondestructive and nonperturbing method to study cancer and other pathologies by analysing tissues, blood, or cells. Due to the exceptional resolution achieved with HRMAS NMR, serial measurements of important metabolites are possible without complex extraction and purification processes.

One major field of industrial applications of HRMAS NMR is the characterization of insoluble polymers swollen in a suitable solvent. Scientific questions typically address physiochemical phenomena, like adhesion, elasticity, or degradation, and their relation to local structures such as the degree of cross-linking or the presence of chain dynamics.

Gels, emulsions, and creams are common in the manufacturing of food, cosmetics and pharmaceuticals. They can be analysed by HRMAS spectroscopy in their original form in an easy and convenient manner, without prior sample treatment.

CMP NMR Probes

Bruker also offers a range of CMP (Comprehensive Multiphase) probes. CMP probes share many similarities with the HRMAS probes, boasting the same high-quality construction, gradients, a lock channel, and compatibility with 4 mm rotors spinning at 15 kHz. In addition to the capabilities of HRMAS probes, Bruker’s CMP probes have been optimized with respect to power handling and thus provide an extended array of experimental techniques, including cross polarization (CP) experiments, and high-power decoupling, enabling researchers to extract even more detailed information from their samples.

For even higher performance in cross polarization and decoupling experiments, Bruker's innovative portfolio includes CPMAS (Cross Polarization Magic Angle Spinning) probes. These probes are designed specifically to optimize cross polarization efficiency and decoupling power, pushing the boundaries of NMR spectroscopy.