For several decades, NMR is known to allow non-invasive measurements of a large variety of systems ranging from quantitative analysis of liquid samples to whole body images of the human body. Whereas theusual NMR approach inserts a probe into a homogeneous magnetic field provided e.g. by a super conducting magnet other methods that have been implemented within the last years are based on single-sided NMR or unilateral NMR. These techniques are based on the use of the stray field of permanent magnets which create the population differences of the quantum mechanical levels necessary to excite and detect NMR signals. These techniques where developed based on the need to provide NMR methods which allow the measurement of large samples which cannot be implemented into super conducting magnets or which cannot be moved to a super conducting magnet. These techniques are based on the magnetic field which can be generated on one side of a magnet. In this regions the magnetic field is very inhomogeneous which is a drawback for NMR methods. This results in line widths being relatively broad compared to those of NMR spectra measured in a super conducting magnet. In particular, the line width within the inhomogeneous field of a single-sided NMR magnet is essentially infinite, i. e. larger than 1 MHz whereas the line width in conventional high-resolution NMR spectroscopy is usually less than 1 Hz. Therefore, quantitative measurements of NMR spectra using single-sided NMR equipment have been problematic in the past.
- highly homogeneous magnetic field external to the magnet
- single sided NMR
- non-invasive measurements
- spectral resolution of 0.25 parts per millon
- multidimensional NMR spectroscopy and imaging
Granted Patents in EP and US.
Juan Perlo et al. “Ex Situ NMR in Highly Homogeneous Fields: 1H Spectroscopy” Science 315, 1110 (2007); DOI: 10.1126/science.1135499