Mobile single-sided NMR

Progress in Nuclear Magnetic Resonance Spectroscopy (Impact Factor: 8.71). 05/2008; 52(4):197-269. DOI: 10.1016/j.pnmrs.2007.10.002
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mobile nuclear magnetic resonance sensors still suffer from relatively high weight and large dimensions, although they are already considerably smaller than superconducting high-field magnets. Application of such sensors for an accurate analysis of rigid materials and thin layers is limited by the echo time of the radiofrequency (rf) coil and the spatial resolution of the sensor. This study presents the construction of a miniaturized NMR-MOUSE® that is reduced to about 90 % in volume and weight compared to a standard Profile NMR-MOUSE®. Thanks to the short dead time of 4 µs of the micro-structured rf coil, short transverse relaxation times of rigid and dry materials can be determined with improved accuracy. Furthermore, it is possible to record depth profiles with high resolution. The large magnetic field gradient of the new set-up leads to enhanced diffusion contrast.
    Applied Magnetic Resonance 12/2014; 46(2). DOI:10.1007/s00723-014-0626-3 · 1.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Single-sided NMR systems have become ubiquitous in industry and laboratory environments due to their low cost, low maintenance and capacity to evaluate quantity and quality of Hydrogen based materials. The performance of such devices has improved significantly over the last decade, providing increased field homogeneity, field strength and even controlled static field gradients. For a class of these devices, the configuration of the permanent magnets provides a linear variation of the magnetic field and can be used in diffusion measurements. However, magnet design depends directly on its application and, according to the purpose, the field homogeneity may significantly be compromised. This work introduces a new approach that extends the usability of diffusion-editing CPMG experiments to NMR devices with highly inhomogeneous magnetic fields, which do not vary linearly in space. Here we propose a method to determine a custom diffusion kernel based on the gradient distribution, which can be seen as a signature of each NMR device. This new diffusion kernel is then utilised in the 2D inverse Laplace transform (2D ILT) in order to determine diffusion-relaxation correlation maps of homogeneous multi-phasic fluids.
    Microporous and Mesoporous Materials 08/2014; 205. DOI:10.1016/j.micromeso.2014.08.026 · 3.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Medium-resolution nuclear magnetic resonance spectroscopy is a promising tool for the monitoring of liquid reactions. For process analytical applications, the requirements of robustness and insensitivity of the spectrometer in relation to high temperatures and pressures are challenging. Within this study, a flow probe using a glass dewar is presented. Temperatures of flowing samples up to 130 °C and pressures up to 40 bar were successfully applied, and the corresponding temperature loss of the flowing sample at 2 ml min−1 was
    Applied Magnetic Resonance 05/2014; 45(5):411-425. DOI:10.1007/s00723-014-0522-x · 1.15 Impact Factor