Stelar s.r.l. - The world leading Company in NMR relaxometry

Comparison of NMRD curves obtained over a six months interval with different Stelar Spinmaster FFC NMR systems. The same 2mM MnCl2 sample has been used. Differences among data at the same frequency are about 1% while the statistical uncertainty of relaxation rates is ~0.5%. This shows the excellent long term reproducibility of the T1's measured by the Stelar FFC relaxometer.

Short Term Reproducibility

Comparison of five NMRD curves obtained in the same working session with a 2mM MnCl2 sample at 25°C. The spread of the data at the same frequency is consistent with the statistical error of T1.

Results of repeated T1 measurement at 10kHz (2mM MnCl2 sample at 20°C). Standard deviation is 0.2% and all data differ by less than 1% from the average.

NMRD curves of MnCl2 aqueous solutions with different concentrations. Even in the presence of relaxation times comparable with, or shorter than, the magnet switching time, all curves display the same type of dispersion characteristic of a diluted MnCl2 solution.

PMRD (Proton Magnetic Relaxation Dispersion) curve of partially dehydrated boiled egg-white. The bump near 2 MHz is due to the 1H- 14N coupling (quadrupole-assisted cross-relaxation glitches).

Deuteron relaxation for GdCl3 in heavy water solution (2 mM). A comparison with proton relaxation sheds light upon the relaxation mechanisms.

L-Lecinamide (a very rigid solid) exhibits a power-law dispersion (T1 µ w) and a strong 14N 'glitches'. The point at 100 MHz was measured by Dr. Belton with a conventional instrument.

Evolution with temperature of the NMRD profile of a Gd-DOTA solution, a standard among the MRI i maging contrast agents.

The broad dispersion observed with an elastomer (rubber) hints to a range of dynamic processes which may be described with a distribution of correlation times. FFC NMR is becoming a basic tool to explore the microscopic dynamics of bulk polymers.

Comparison of the relaxivities of two MnCl2 solutions (12.5mM and 25mM). As expected, the two curves overlap nicely.

NMRD curves of GdCl3 in water at different concentrations. Note that no dispersion is seen in the sub-MHz region and that the spread of the data in this plateau increases as the relaxation times become comparable with the magnet switching time (~1 ms).

NMRD curve of Perspex at 18°C with a strong low frequency dispersion.

NMRD curve of Hexamethylbenzene (solid sample). The dispersion occurs only below 20 kHz and it is difficult to characterize with methods other than FFC.

NMRD profile of liquid paraffin displays two different regimes, above and below 1 MHz.

NMRD profile of a contrast agent obtained on the behalf of a potential costumer.

NMRD profile of Liquid Crystal (CBOOA).
The contributions of different mechanisms of relaxation may be identified and/or computed and the experimental curve is fitted with a restricted number of adjustable parameters. These parameters are related with fundamental properties of the systems (hydrodynamic modes, order fluctuations, etc.).