EP0277745A2
Expired / Lapsed
EP
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Methods and apparatus for detecting certain compounds
Assignee: BTG International Ltd
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Filing: 1988-01-26
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Granted: —
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Expires: 2008-01-26
Abstract
Abstract The detection of compounds containing both nuclei of a kind which exhibit nuclear magnetic resonance (nmr) and nuclei of a kind which exhibit nuclear quadrupole resonance (nqr), for example compounds containing both ¹H and ¹⁴H nuclei, is carried out by subjecting a substance suspected of containing such a compound to a magnetic field and repetitively to three parallel activities A,H and B. Activity A comprises two similar rf pulse sequences P A and P B at the nmr frequency. Activity H is a temporary change in the value of the magnetic field, which may be a reduction to zero. Activity B is the application of additional rf signals. Activity H and/or activity B are different during each of the respective pulse sequences P A and P B . The activity B rf signals are at one or more frequencies selected so that in combination with the activity H in at least one of the pulse sequences the subsequent nmr signal is modified if such a compound is present. The difference in magnitude of the nmr signals obtained following the two types of rf pulse sequence is then measured.
Inventors
- 👤 John Alec Sydney Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:51
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/46; G01R33/441
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
171 words
A method of detecting the presence of one or more compounds containing both nuclei of a first kind which exhibit nmr and nuclei of a second kind which exhibit nqr comprising subjecting material suspected of containing such a compound to a magnetic field and successive and repetitively to two types of sequence, each sequence comprising an rf pulse or pulse train at the nmr frequency of the first kind of nucleus in the said magnetic field followed by a time interval in which in at least one of the sequences there is a predetermined change in the magnitude of the aid magnetic field, and during the time interval in at least one of the types of sequence applying rf signals at one or more frequencies selected so that in combination with the aforesaid change in the magnitude of the magnetic field the subsequent nmr signal is modified if such a compound is present, and measuring the difference in the magnitude of the nmr signals obtained following the two types of sequence.
Claim 2
Independent Claim
171 words
A method of detecting the presence of one or more compounds containing both nuclei of a first kind which exhibit nmr and nuclei of a second kind which exhibit nqr comprising subjecting material suspected of containing such a compound to a magnetic field and successive and repetitively to two types of sequence, each sequence comprising an rf pulse or pulse train at the nmr frequency of the first kind of nucleus in the said magnetic field followed by a time interval in which in at least one of the sequences there is a predetermined change in the magnitude of the aid magnetic field, and during the time interval in at least one of the types of sequence applying rf signals at one or more frequencies selected so that in combination with the aforesaid change in the magnitude of the magnetic field the subsequent nmr signal is modified if such a compound is present, and measuring the difference in the magnitude of the nmr signals obtained following the two types of sequence.
Claim 3
Dependent Claim
19 words
The method as claimed in Claim 1 in which the rf pulse train comprises a sequence of 90° pulses.
Claim 4
Dependent Claim
42 words
The method as claimed in Claim 2 in which the pulse train comprises a spin locking pulse sequence comprising 90° pulses of the form 90°₀-τ-(90°₉₀-2τ) n where τ is a time delay and n is an integer of value one or more.
Claim 5
Dependent Claim
17 words
The method as claimed in Claim 1 in which the rf pulse is a single 90° pulse.
Claim 6
Independent Claim
21 words
The method as claimed in any one of the preceding claims in which the two parts of sequence are applied alternately.
Claim 7
Independent Claim
38 words
The method as claimed in any one of Claims 1 to 4 in which a plurality of one type of sequence is first applied and is then followed by an equal plurality of the other type of sequence.
Claim 8
Independent Claim
30 words
The method as claimed in any one of the preceding claims in which there are predetermined changes in the magnitude of the said magnetic fluid in both types of sequence.
Claim 9
Independent Claim
61 words
The method as claimed in any one of the preceding claims in which the changes in the magnitude of the magnetic field are changes to a zero or low value and rf signals at the nqr frequency of one or more compounds which it is desired to detect are applied in the time interval of one of the types of sequence.
Claim 10
Dependent Claim
40 words
The method as claimed in Claim 8 in which rf signals which are not at the nqr frequency of any of the compounds of interest are applied during the corresponding time interval of the other of the types of sequence.
Claim 11
Independent Claim
67 words
The method as claimed in any one of claims 1 to 7 in which the change in the magnitude of the static magnetic field during one of the types of sequence is a stepped change with at least one of the steps being held at a value in which level crossing between nuclei of the two kinds takes place if corresponding ones of said compounds are present.
Claim 12
Dependent Claim
29 words
The method as claims in Claim 10 in which the rf signals are applied when the magnetic field reaches zero value in order to destroy any residual nmr signal.
Claim 13
Independent Claim
38 words
The method as claimed in any one of Claims 1 to 7 in which the changes in the magnitude of the static magnetic field are different in the respective time intervals of each of the types of sequence.
Claim 14
Dependent Claim
69 words
13 The method as claimed in Claim 12 in which one of the changes is such as to cause the nmr frequency of the first kind of nuclei to coincide with one of the nqr frequencies of nuclei of the second kind in a compound which it is desired to detect and simultaneously rf signals are applied at a frequency corresponding to a different nqr frequency of such nuclei.
Claim 15
Dependent Claim
126 words
Apparatus for detecting the presence of one or more compounds containing both nuclei of a first kind which exhibit nmr and nuclei of a second kind which exhibit nqr comprising: means for applying a magnetic field to material to be tested means for applying rf pulses to such material of predetermined radio-frequency, intensity, duration and phase at the nmr frequency of nuclei of the first kind; means for temporarily changing the magnitude of the said magnetic field in a predetermined manner; means for applying rf signals to such materials during the time of said temporary change of magnitude of the said magnetic field said signals being of one or more predetermined frequencies; and means for measuring the free induction signal from nuclei of the first kind.
Claim 16
Dependent Claim
126 words
Apparatus for detecting the presence of one or more compounds containing both nuclei of a first kind which exhibit nmr and nuclei of a second kind which exhibit nqr comprising: means for applying a magnetic field to material to be tested means for applying rf pulses to such material of predetermined radio-frequency, intensity, duration and phase at the nmr frequency of nuclei of the first kind; means for temporarily changing the magnitude of the said magnetic field in a predetermined manner; means for applying rf signals to such materials during the time of said temporary change of magnitude of the said magnetic field said signals being of one or more predetermined frequencies; and means for measuring the free induction signal from nuclei of the first kind.
Claim 17
Dependent Claim
28 words
Apparatus as claimed in Claim 14 in which separate rf coil means are provided to which the said rf pulses and the said rf signals respectively are applied.
Claim 18
Dependent Claim
31 words
Apparatus as claimed in Claim 14 or Claim 15 in which two separate receiving channels are provided to receive different ones of free induction signals from nuclei of the first kind.
References Cited (Backward Citations)
No citation records indexed.
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