ABSTRACT
Recently the capabilities of single sided nuclear magnetic resonance (NMR) devices have been extended towards three-dimensional imaging. This paper details the use of a magnetic field sweep coil to obtain spatial resolution in the plane normal to the surface of a hand-held NMR device-the NMR-Mobile Universal Surface Explorer (MOUSE). One-dimensional depth profiles can be recorded by varying the current in the sweep coils. Preliminary results from multi-layer rubber and glass sample phantoms demonstrate a sample penetration depth of 7 mm. Two-dimensional images were acquired via the inclusion of phase encoding coils. Non-destructive cross-sectional images of small rubber phantoms were successfully recorded.
ABSTRACT
The application of the NMR-MObile Universal Surface Explorer (NMR-MOUSE) to study food systems is evaluated using oil-in-water emulsions, and the results are compared to those obtained using a conventional low-field NMR (LF-NMR) instrument. The NMR-MOUSE is a small and portable LF-NMR system with a one-sided magnet layout that is used to replace the conventional magnet and probe on a LF-NMR instrument. The high magnetic field gradients associated with the one-sided MOUSE magnet result in NMR signal decays being dominated by molecular diffusion effects, which makes it possible to discriminate between the NMR signals from oil and water. Different data acquisition parameters as well as different approaches to the analysis of the NMR data from a range of oil-in-water emulsions are evaluated, and it is demonstrated how the concentration of oil and water can be determined from the NMR-MOUSE signals. From these model systems it is concluded that the NMR-MOUSE has good potential for the quantitative analysis of intact food products.
