Nuclear magnetic resonance analysis of multiple samples

• US 6,696,838 B2
• Filed: 08/24/2001
• Issued: 02/24/2004
• Est. Priority Date: 02/26/1999
• Status: Expired due to Fees

• Current Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Original Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Inventors: Raftery, Daniel, McNamara, Ernesto, Fisher, George G.
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): Fetzner, Tiffany A.
• Application Number:
  US09/938,996
• Publication Number:
  US 20020130661A1
• Time in Patent Office: 914 Days
• Field of Search: 324/321, 324/318, 324/309, 324/307, 324/310, 435/7.1
• US Class Current: 324/321
• CPC Class Codes: G01R 33/302 Miniaturized sample handling arrangements for sampling small quantities, e.g. flow-through microfluidic NMR chips
• CPC Class Codes: G01R 33/307 specially adapted for moving the sample relative to the MR system, e.g. spinning mechanisms, flow cells or means for positioning the sample inside a spectrometer
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil
• CPC Class Codes: G01R 33/365 Decoupling of multiple RF coils wherein the multiple RF coils have the same function in MR, e.g. decoupling of a receive coil from another receive coil in a receive coil array, decoupling of a transmission coil from another transmission coil in a transmission coil array
• CPC Class Codes: G01R 33/422 of the radio frequency field

Abstract

A Nuclear Magnetic Resonance (NMR) probe device (20) is disclosed. NMR probe device (20) includes a plurality of detection coils (30, 40) each operable to detect a signal from a corresponding one of a plurality of samples (34, 44) undergoing NMR analysis. Also included is a plurality of tuning circuits (31, 41, 38, 48) each coupled to one of detection coils (30, 40) to tune the one of the detection coils (30, 40) to a corresponding resonant frequency for the NMR analysis of the corresponding one of the samples. An electromagnetic shield (22) is positioned between a first one of the detection coils (30, 40) and a second one of the detection coils (30, 40) to isolate the first one of the detection coils (30, 40) and the second one of the detection coils (30, 40) from each other.

Claims

1. An NMR apparatus, comprising:

an NMR transmitter for transmitting one or more signals to a number of samples;

a number of sample holders each operable to receive a corresponding one of the samples for NMR analysis;

a plurality of detection coils each operable to detect a an individual response of a corresponding one of the samples to one or more signals from said NMR transmitter;

an adjustable magnetic field source proximate to a sample space arranged to receive said sample holders, said magnetic field source being operable to selectively provide;

a first magnetic field to generate a first collective response of the samples when received in said sample space and excited by said one or more signals from said NMR transmitter,

a second magnetic field having a gradient relative to said first magnetic field to generate a second collective response of the samples when received in said sample space and excited by said one or more signals from said NMR transmitter, said second collective response corresponding to a number of different frequency shifts relative to said first collective response, said different frequency shifts of said second collective response each corresponding to a different one of the samples; and

a processor operable to determine a number of spectral characterizations as a function of said first collective sample response and said second collective sample response, the spectral characterizations each being representative of a different one of the samples.

2. The apparatus of claim 1, wherein said first response corresponds to an unshifted composite spectrum of the samples, said second response corresponds to a shifted composite spectrum of the samples, and said processor is operable to establish a spectral mask for each of said detection coils from said first response and said second response during determination of the spectral characterizations.

3. The apparatus of claim 1, wherein said processor is operable to perform reference deconvolution during determination of the spectral characterizations.

4. The apparatus of claim 1, wherein said processor is operable to perform multidimensional NMR analysis.

5. The apparatus of claim 1, wherein the first magnetic field is generally homogeneous in said sample space.

6. The apparatus of claim 1, wherein said detection coils number at least four.

7. The apparatus of claim 1, further comprising an NMR receiver coupled to said detection coils and a control to selectively adjust the gradient.

8. The apparatus of claim 1, wherein said sample holders are each in fluid communication with sample instrumentation to perform capillary electrophoresis.

9. The apparatus of claim 1, wherein said sample holders are each mounted in a probe device sized for insertion in said sample space, said probe device including a vessel to dispose a susceptibility fluid about said sample holders when received in said sample space.

10. An NMR method, comprising:

operating an NMR spectroscopy system including a sample space, a transmitter, and a plurality of detection coils each disposed about a corresponding one of a plurality of separated samples in the sample space;

generating a first magnetic field in the sample space;

exciting the samples substantially simultaneously with an RF signal during generation of the first magnetic field;

detecting a first collective response of the samples as a result of the first magnetic field and RF excitation;

generating a second magnetic field in the sample space, the second magnetic field including a gradient relative to the first magnetic field;

exciting the samples substantially simultaneously with an RF signal during generation of the second magnetic field;

detecting a second collective response from the samples as a result of the second magnetic field and RF excitation, said second collective response corresponding to a number of different frequency shifts relative to said first collective response, said different frequency shifts of said second collective response each corresponding to a different one of the samples; and

determining a number of spectral characterizations as a function of said first collective sample response and said second collective sample response, the spectral characterizations each being representative of a different one of the samples.

11. The method of claim 10, further comprising performing a multidimensional NMR analysis of the samples.

12. The method of claim 10, wherein said determining includes establishing a spectral mask for each of the detection coils.

13. The method of claim 10, wherein said determining includes performing reference deconvolution.

14. The method of claim 10, wherein the first and second sample responses each correspond to a composite spectrum.

15. The method of claim 10, wherein said detection coils number at least four and are each of a microcoil variety with a diameter of less than about 1 millimeter.

16. The method of claim 10, wherein the detection coils are each disposed about a respective one of a number of tubes, and the tubes are each arranged to receive the corresponding one of the samples.

17. An NMR apparatus, comprising:

an NMR transmitter for transmitting one or more signals to a number of samples, wherein the number of samples is two or more;

a number of sample holders each operable to receive a corresponding one of the samples for NMR analysis;

a plurality of detection coils electrically connected in parallel, each detection coil operable to detect a response of the corresponding one of the samples to one or more signals from said NMR transmitter;

an adjustable magnetic field source proximate to a sample space arranged to receive said sample holders, said magnetic field source being operable to selectively provide;

a first magnetic field which generates a response from at least a first one of the samples when received in said sample space and excited by an RF signal from said NMR transmitter,

a second magnetic field having a gradient relative to said first magnetic field to generate a response from at least a second one of the samples when received in said sample space and excited by an RF signal from said NMR transmitter, wherein the response from the second sample to said second magnetic field corresponds to a frequency shift relative to the response from said second sample that would have occurred as a result of an excitation during the generation of said first magnetic field;

a common receiver connected to each of said detection coils; and

a processor coupled to an output of said common receiver and operable to determine separate spectral characterizations for each response to the first magnetic field and each response to the second magnetic field.

18. The apparatus of claim 17, wherein the first magnetic field is generally homogeneous in said sample space.

19. The apparatus of claim 17, wherein said detection coils are each of a microcoil variety with a diameter of less than about one millimeter.

20. An NMR method, comprising:

operating an NMR spectroscopy system including a sample space, a transmitter, and a plurality of detection coils each disposed about a corresponding one of a plurality of separated samples in the sample space, wherein said detection coils are electrically connected in parallel and connected to a common receiver;

generating a first magnetic field in the sample space;

applying a first excitation pulse to the sample space;

detecting a response from at least a first one of the samples to the first magnetic field and said first excitation pulse;

generating a second magnetic field in the sample space, the second magnetic field including a gradient relative to the first magnetic field;

applying a second excitation pulse to the sample space;

detecting a response from at least a second one of the samples to the second magnetic field and said second excitation pulse, wherein the response from the second sample to said second magnetic field corresponds to a frequency shift relative to the response from said second sample that would have occurred as a result of an excitation during the generation of said first magnetic field; and

determining a plurality of NMR spectra from the responses, one NMR spectrum corresponding to the response from the first one of the samples to the first magnetic field and first excitation pulse, another NMR spectrum corresponding to the response from the second one of the samples to the second magnetic field and second excitation pulse.

21. The method of claim 20, wherein the first magnetic field is generally homogeneous in said sample space.

22. The method of claim 20, wherein said detection coils are each of a microcoil variety with a diameter of less than about one millimeter.