Mobile NMR started in the well logging industry. Early on, benchtop NMR devices were developed to be deployed inside the borehole to characterize the fluids of the well downhole . The successful NMR analyzer well-logging devices measure distributions of relaxation and diffusion parameters in the stray field of permanent magnets .
The same principle is followed with the much smaller NMR-MOUSE , which has a higher field, a stronger gradient, and a smaller sensitive volume. It is used for nondestructive materials testing of large objects such as rubber tires, polymer pipes, and objects of art . Today, the NMR force microscope is the smallest stray-field NMR device .
While the sensitive volume of stray-field NMR devices can be shaped with proper magnet design , the sensitivity can significantly be improved only by enlarging the sensitive volume and the field strength, a strategy which returns mobile NMR to the roots of NMR spectroscopy and imaging with closed magnets.
In fact, a variety of desktop MRI magnets has been pioneered by Kose , and the first miniature spectroscopy magnet has been developed by McDowell . Today miniature NMR gadgets are targeted for specific detection of biomarkers , and the first desktop NMR spectrometers for chemical analysis by high-resolution NMR appear on the market .
The advances in mobile NMR are expected to benefit from the progress in developing widely applicable and miniaturized hyperpolarization methodologies, alternative detection schemes, microfluidic components for sample preparation and handling, the use of high-TC superconducting magnets, and the development of user-friendly apps for different types of information-driven measurements by untrained NMR consumers.