Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials

1. A method comprising:

obtaining an NMR measurement from a sample wherein an ultra-low field NMR system probes the sample and produces the NMR measurement and wherein a sampling temperature, prepolarizing field, and measurement field are known;

detecting the NMR measurement by means of inductive coils;

analyzing the NMR measurement to obtain at least one measurement feature wherein the measurement feature comprises T1, T2, T1ρ, or the frequency dependence thereof; and,

searching for the at least one measurement feature within a database comprising NMR reference data for at least one material to determine if the sample comprises a material of interest.

2. The method of claim 1 wherein the dependence of measurement features are obtained as a function of a Larmor frequency of from about 1 kHz to about 40 kHz.

3. The method of claim 1 , wherein the dependence of measurement features are obtained as a function of the pre-polarizing field strength.

4. The method of claim 1 wherein the material of interest is a liquid hazardous material, a food, a beverage, a substance indicative of food quality, a pharmaceutical product, or a pharmaceutical by-product.

5. The method of claim 1 wherein the inductive coils form a sensor array.

6. The method of claim 1 wherein the sample is encased in a conductive shell.

7. The method of claim 1 wherein the sample is inside a mammalian body.

8. The method of claim 1 , wherein the sample is a nonferromagnetic container.

9. A method comprising:

measuring a sampling temperature;

obtaining an NMR measurement and an interior image from a sample wherein an ultra-low field NMR system probes the sample and produces the NMR measurement and wherein a sampling temperature, prepolarizing field, and measurement field are known;

detecting the NMR measurement by means of inductive coils;

analyzing the NMR measurement to obtain at least one measurement feature;

searching for the at least one measurement feature within a reference library comprising NMR reference data for at least one material to determine if the sample comprises a material of interest.

10. The method of claim 9 wherein the interior image is an NMR image produced by the ultra-low field NMR system.

11. The method of claim 9 wherein the magnetic coils form a sensor array, wherein spatial sensitivity encoding is used to provide an image of the target volume within the sample; and wherein the NMR measurement corresponds to a composition within the target volume.

12. The system of claim 9 further comprising identifying a target volume from the interior image, wherein the wherein the magnetic coils form a sensor array, wherein the spatial dependence of the prepolarizing and measurement fields are used to produce an image of the target volume, and wherein the NMR measurement corresponds to a composition with the target volume.

13. The method of claim 9 wherein the material of interest is a hazardous material, a food, a beverage, a substance indicative of food quality, a pharmaceutical product, or a pharmaceutical by-product.

14. A method comprising:

passing an container through a scanning system comprising an ultra-low field NMR system wherein the container is unopened, wherein the ultra-low field NMR system probes the container and produces an NMR measurement and wherein a sampling temperature, prepolarizing field, and measurement field are known and wherein the pre-polarizing magnetic field and the measurement magnetic field are different;

detecting the NMR measurement by means of inductive coils;

analyzing the NMR measurement to obtain at least one measurement feature;

searching for the at least one measurement feature within a database comprising comprising NMR reference data for at least one material to determine if the sample comprises a material of interest.

15. The method of claim 14 wherein the container is luggage.

16. The method of claim 14 , wherein the container is a nonferromagnetic container.

17. The method of claim 14 wherein the container comprises a conductive shell.

18. The method of claim 14 wherein the container contains smaller containers comprising conductive shells.

19. The method of claim 14 further comprising obtaining an interior image of the container wherein the scanning system further comprises an interior imaging system.

20. The method of claim 19 further comprising identifying a target volume within the container, wherein the inductive coils form a sensor array, and wherein the NMR measurement corresponds to a composition with the target volume.