Methods and apparatus for analysis of sealed containers

Patent metadata

Field	Value
Publication number	US-2016003753-A1
Application number	US-201414772068-A
Country	US
Kind code	A1
Filing date	Mar 4, 2014
Priority date	Mar 4, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

This invention relates to methods and devices for NMR spectroscopy analyzing sealed containers e.g., food and beverage containers and other containers, and particularly according to specific embodiments sealed containers made of a conducting but generally nonferromagnetic metal or other conducting material. As discussed in above referenced applications, many current strategies for contaminant detection require a container to be violated, a process that can destroy the container or product and is impractical in large scale applications. The present invention overcomes these and other problems by providing methods and devices for the detection of contaminants and/or contraband in metal or conducting containers by NMR spectroscopy.

First claim

What is claimed:

1 . A method of analyzing one or more contents of one or more sealed containers, the method comprising:
providing an NMR spectrometer and an NMR probe configured to accept a portion of the sealed container, all of the sealed container, or a portion or all of a plurality of sealed containers; positioning said portion of the sealed container, all of the sealed container, or a portion or all of a plurality of sealed containers within a data collection region of the NMR probe; establishing a homogeneous static magnetic field across the data collection region; applying an amplitude and frequency swept shaped RF pulse; collecting an NMR spectrum; and analyzing the NMR spectrum, thereby analyzing one or more contents of the one or more sealed containers.

2 . The method of claim 1 , further wherein the RF pulse is a high powered pulse of at least 0.5 kW.

3 . The method of claim 1 , further wherein the shaped RF pulse is one or more of:
a frequency and amplitude modulated adiabatic half soliton pulse; one or more adiabatic RF pulses; one or more adiabatic RF pulses in a mixture of pulses; a half soliton hyperbolic pulses; one or more linear and non-linear frequency and amplitude sweeps; and one or more mixtures of constant and variable amplitude and frequency changes.

4 . The method of claim 1 , further wherein the shaped RF pulse is selected based on specific system configurations and on conductive properties of the containers.

5 . The method of claim 1 , further wherein the shaped RF pulse is obtained by sweeping the frequency from a small frequency value (e.g., 12.5 Hz) below resonance up to resonance in a hyperbolic tangent fashion in a selected interval (e.g., 100 ms) while increasing the power amplitude.

6 . The method of claim 1 , further wherein the shaped RF pulse is obtained by sweeping the frequency value in a selected interval while varying power amplitude.

7 . The method of claim 1 , further wherein the shaped RF pulse is applied a number of times to obtain multiple free induction signals that are averaged to determine the spectra.

8 . The method of claim 1 , wherein the one or more contents comprise a liquid or a solid.

9 . The method of claim 8 , wherein the one or more contents comprise hydrogen atoms, and wherein the NMR probe comprises a 1 H NMR probe.

10 . The method of claim 1 , wherein collecting the NMR data comprises block averaging of data sets.

11 . The method of claim 1 , wherein examining the NMR spectrum further comprises determining a concentration of one or more components of the contents.

12 . The method of claim 1 , further wherein the method obtains chemically resolved 1 H NMR spectra from materials inside containers made from radio shielding or radio attenuating materials.

13 . The method of claim 1 , further wherein the sealed container is one or more of:
standard containers (e.g., cans, jars, boxes, bottles, bags, kegs, etc.) having non-ferrous metallic compositions in the container materials; aluminum containers; other metallic or non-metallic containers that provide RF shielding.

14 . The method of claim 1 , further wherein the sealed container is a commonly available stream-of-commerce, non-ferrous metal container.

15 . The method of claim 1 , further wherein the method performs one or more of:
detecting one or more molecular components to provide an evaluation of foodstuffs or other materials; and detecting one or more molecular components for forensic examination of materials in containers for dangerous or contraband substances.

16 . The method of claim 1 , further comprising:
applying a near field mid-range high powered shaped frequency RF signal selected to provide a detectable NMR precession signal from substances in conducting radio shielding containers to perform NMR.

17 . The method of claim 1 , further wherein the applied RF signal has a frequency between about 3 to about 10 MHz.

18 . The method of claim 1 , further wherein the applied RF signal has a frequency between about 4 to about 6 MHz.

19 . The method of claim 1 , further wherein the applied RF signal has a frequency between about 4 MHz<ω 0 <7 MHz range to provide sensitivity for stream-of-commerce metal containers with wall thicknesses between about 75 μm and 120 μm.

20 . The method of claim 1 , further comprising:
applying high power shaped RF pulses to the outside of a metal or RF shielding container such that the attenuation of the RF amplitude by the metal container presents a low power broadband excitation pulse to the container contents; and wherein the low power broadband excitation pulse causes large free precession signals from the contents which are then detected outside the container.

21 . The method of claim 20 , further comprising:
selecting an RF frequency and a static magnetic field strength such that substances in the container are excited sufficiently to produce a detectable precession signal.

22 . The method of claim 1 , further wherein the pulses are from the family of broadband frequency and amplitude modulated adiabatic pulses.

23 . The method of claim 1 , further comprising:
broadcasting shaped adiabatic high power micro-second (μs) time scale RF pulses; and receiving and analyzing longer time scale low power RF free precession signals.

24 . The method of claim 23 , further wherein during broadcast, the RF pulses are applied to a tuned LC tank circuit with impedance providing a RF current that ultimately results in a RF magnetic field with amplitude B app that rotates the equilibrium magnetization M o of NMR susceptible contents away from the large applied static magnetic field B o to the perpendicular transverse plane.

25 . The method of claim 23 , wherein the broadcast field (designated B app ) and the received voltage (designated V NMR ) are reduced according to a shielding effectiveness (SE) of the container.

26 . The method of claim 25 wherein the shielding effectiveness (SE) is determined from: B 1 metal =10 −SE/20 B 1 app | and V metal =10 −SE/20 V NMR wherein the container is a solenoid RF coil enclosing a standard 12 oz aluminum container along the x direction of the laboratory frame where the z axis is defined by the direction of the static magnetic field.

27 . The method of claim 26 , wherein the SE calculations for a closed, cylindrical, 100 μm wall thickness standard aluminum beverage container uses the simplified SE for an infinitely long conducting metal cylinder as an analytical approximation.

28 . The method of claim 26 , wherein the SE is calculated by:

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Assignees

• Univ California
• Madison Avenue Man Co Inc

Inventors

• Augustine Matthew P
• Lim Victor
• Broz Joseph S

Classifications

• G01N24/084 Primary

  Detection of potentially hazardous samples, e.g. toxic samples, explosives, drugs, firearms, weapons · CPC title

• G01R33/4625

  Processing of acquired signals, e.g. elimination of phase errors, baseline fitting, chemometric analysis · CPC title

• G01R33/30

  Sample handling arrangements, e.g. sample cells, spinning mechanisms · CPC title