NMR Discrimination Apparatus and Method Therefor: 4,166,972

A method and apparatus for enhanced nuclear magnetic resonance (NMR) discrimination and detection is disclosed. In the preferred embodiment, a sample which has a first atomic element is placed in a magnetic field of a first intensity. A reaction between the nuclei of the first atomic element and the electromagnetic field of the apparatus produces an NMR response which is tunable with field intensity. If the first atomic element of interest is present and intimately comingled with a second atomic element of interest, as might occur in compounds, and if the second element of interest has a nuclear quadrupolar moment and if the molecular structure conditions are proper for it to have a nuclear quadrupolar resonance (NQR), then adjustment of the magnetic field intensity varies the NMR frequency of the first element of interest to coincide with the NQR frequency of the second element of interest. Energy is then transferred in an enhanced fashion between the nuclei of the first element of interest and the nuclei of the second element of interest. This increased ease of transfer of energy between the two nuclei under the foregoing conditions reduces the NMR response time of the first element thereby improving the detectability of that element. Implementation of this effect is the basis for the reduced detection time and the improved discrimination achieved in the apparatus of this invention. A second aspect of the discrimination capabilities of the apparatus is achieved by varying the elapsed time between successive observations of the NMR response of the first element of interest. An apparatus and method allow the detection and measurement of a first element of interest in a particular compound while rejecting the NMR response from the same element located in different compounds.