INSULATOR AND/OR CONSTRUCTION MATERIAL FOR NMR APPLICATIONS

Abstract

A compound consisting of the following components: (A) 40-99.99 weight percent of at least one thermoplastic or thermoset polymer material selected as a halogenated or perhalogenated polymer; (B) 0.01-60 weight percent of at least one inorganic particulate diamagnetic or paramagnetic material; (C) 0-39.99 weight percent of at least one additive different from (B); is proposed as a construction material in the detection-relevant spatial area (9) of a nuclear magnetic resonance device with a static magnetic field of at least 1 Tesla, and furthermore corresponding constructional elements, in particular sample holders, our proposed as well as method of manufacturing such constructional elements and uses of such constructional elements.

Claims

1. A method of using a compound consisting of the following components: (A) 40-99.99 weight percent of at least one thermoplastic or thermoset polymer material selected as a halogenated or perhalogenated polymer; (B) 0.01-60 weight percent of at least one inorganic or metallo-organic particulate diamagnetic or paramagnetic material; (C) 0-39.99 weight percent of at least one additive different from; as a construction material in the detection-relevant spatial area of a nuclear magnetic resonance device with a static magnetic field of at least 1 Tesla.

2. The method according to claim 1, wherein the polymer material of component is selected as a halogenated or perhalogenated polymer, with at least one of a melting point and decomposition point of at least 100? C., and/or wherein the component (A) is a thermoplastic polymer.

3. The method according to claim 1, wherein the component and/or the component and/or the component or the whole compound is free or essentially free from .sup.1H hydrogen, and/or wherein the compound is fully or essentially fully deuterated.

4. The method according to claim 1, wherein the inorganic or metallo-organic particulate diamagnetic or paramagnetic material is a metal salt including metal oxides.

5. The method according to claim 1, wherein the proportion of component is in the range of 0.05-20 weight percent.

6. The method according to claim 1, wherein the magnetic volume susceptibility of the compound is adapted by a corresponding proportion of component to match the magnetic volume susceptibility of the sample solvent.

7. The method according to claim 1, wherein the proportion of component is in the range of 0-5 weight percent.

8. A compound consisting of the following components: (A) 40-99.99 weight percent of at least one thermoplastic or thermoset polymer material selected as a halogenated or perhalogenated polymer; (B) 0.01-60 weight percent of at least one inorganic particulate diamagnetic or paramagnetic material; (C) 0-39.99 weight percent of at least one additive different from; for use as a construction material in the detection-relevant spatial area of a nuclear magnetic resonance device with a static magnetic field of at least 1 Tesla.

9. A construction element and/or isolation element for use in the detection-relevant spatial area of a nuclear magnetic resonance device with a static magnetic field of at least 1 Tesla comprising or consisting of a compound according to claim 8.

10. The construction element according to claim 9 in the form of a nuclear magnetic resonance sample holder comprising or consisting of, at least in the detection relevant spatial area, of said compound.

11. A nuclear magnetic resonance sample holder according to claim 10 in the form of a container for a liquid sample comprising a substance to be analysed in dissolved and/or suspended form, wherein the magnetic volume susceptibility of said compound is matched to one of the solvent of the liquid sample.

12. The nuclear magnetic resonance sample holder according to claim 11, comprising a cavity for the liquid sample, the volume of which is restricted to the detection area of the nuclear magnetic resonance device for which the sample holder is suitable and adapted, while further portions of the sample holder are made of bulk of said compound with the exception of at least one of inlet means, closure means, volume compensation means, sealing/retaining means or comprising a cavity for the liquid sample, the volume of which cavity is restricted to the detection area of the nuclear magnetic resonance device for which the sample holder is suitable and adapted, and which cavity is confined radially by a cylindrical glass sample tube, and bordered on at least one axial side, by at least one plug of said compound, inserted into said glass sample tube, wherein at the interface between the liquid sample and the at least one plug the liquid sample and the plug material are directly adjacent to each other.

13. The nuclear magnetic resonance sample holder according to claim 11, comprising a lower solid material portion, an adjacent sample cavity portion and an upper solid material portion.

14. A method of using a nuclear magnetic resonance sample holder according to claim 11 for measuring a liquid sample using nuclear magnetic resonance, wherein the magnetic volume susceptibility of the compound of the sample holder is adapted to one of the liquid of the sample.

15. A method of manufacturing a nuclear magnetic resonance sample holder according to claim 11, wherein a compound consisting of the following components: (A) 40-99.99 weight percent of at least one thermoplastic or thermoset polymer material selected as a halogenated or perhalogenated polymer; (B) 0.01-60 weight percent of at least one inorganic particulate diamagnetic or paramagnetic material; (C) 0-39.99 weight percent of at least one additive different from (B); is used to form the sample holder.

16. The method according to claim 1, wherein the polymer material of component is selected as a halogenated or perhalogenated polymer, with at least one of a melting point and decomposition point of at least 200? C. or at least 300? C.

17. The method according to claim 1, wherein the polymer material of component is selected as a polymer free from 1H and/or with low dielectric losses, including selected from the group consisting of (per)fluoropolymers, (per)chloropolymers, or (per)fluororchloropolymers.

18. The method according to claim 1, wherein the polymer material of component (A) is selected from the group consisting of: polyvinylfluoride, polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, perfluoroalkoxy polymer, fluorinated ethylene-propylene, polyethylenetetrafluoroethylene, polyethylenechlorotrifluoroethylene, perfluorinated elastomer, fluorocarbon [chlorotrifluoroethylenevinylidene fluoride], fluoroelastomer [tetrafluoroethylene-Propylene], or chlorinated analogues or blends thereof.

19. The method according to claim 1, wherein the paramagnetic material is a transition metal salt including transition metal oxides, or wherein the inorganic or metallo-organic particulate paramagnetic material is selected from the group consisting of: cerium oxide, including selected as chromium oxide, ZrO.sub.2, TiO.sub.2, Y.sub.2O.sub.3, paramagnetic manganese oxide, including selected from MnO, MnO.sub.2, Mn.sub.3O.sub.4 or CeO.sub.2, or a mixture or combined salt thereof.

20. The method according to claim 1, wherein the inorganic or metallo-organic particulate paramagnetic material is selected from the group consisting of: chromium oxide, CeO.sub.2, or a combination thereof.

21. The method according to claim 1, wherein the proportion of component is in the range of 0.1-2 or 0.1-1 weight percent, or in the range of 0.1-0.3 weight percent.

22. The method according to claim 1, wherein the magnetic volume susceptibility of the compound is adapted by a corresponding proportion of component to match the magnetic volume susceptibility of water at room temperature.

23. The method according to claim 1, wherein the proportion of component is in the range of 0.1-2 weight percent, and wherein component compound is free or essentially free from .sup.1H.

24. The nuclear magnetic resonance sample holder according to claim 11, comprising a cavity for the liquid sample, the volume of which cavity is restricted to the detection area of the nuclear magnetic resonance device for which the sample holder is suitable and adapted, and which cavity is confined radially by a circular cylindrical glass sample tube, and bordered on both axial sides, by at least one circular cylindrical plug of said compound, inserted into said glass sample tube, wherein at the interface between the liquid sample and the at least one plug the liquid sample and the plug material are directly adjacent to each other, and wherein the outer diameter of said at least one plug essentially corresponds to the inner diameter of said glass sample tube.

25. The nuclear magnetic resonance sample holder according to claim 11, comprising a lower solid material portion, an adjacent sample cavity portion and an upper solid material portion, wherein said upper solid material portion comprises a plug essentially made of said compound.

26. The method according to claim 14, wherein the magnetic volume susceptibility is adapted to the magnetic volume susceptibility of the NMR solvent, selected from at least one of water, acetone, methanol, chloroform, in deuterated or undeuterated form.

27. The method according to claim 15, wherein the compound is used to form the sample holder, in a machining, after powder mixing of (A)-(C) until a homogenous powder mixture is obtained and subsequent sintering at elevated temperature of at least at least 200? C. or at least 300? C., at elevated pressure, including of at least 100 kg/cm.sup.2, at least 200 kg, or at least 250 kg/cm.sup.2, and/or in an injection moulding process, and wherein the proportion of component is adapted so that the magnetic volume susceptibility of the sample holder matches with the magnetic volume susceptibility of the sample to be held

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

[0096] FIG. 1 shows a conventional high-resolution nuclear magnetic resonance measurement setup in a cylindrical high magnetic field magnet in an axial cut; shows a detailed axial cut through the measurement area of the high-resolution FIG. 2 nuclear magnetic resonance measurement setup for liquid state NMR measurements;

[0097] FIG. 3 schematic axial cut through a susceptibility matched container for high-resolution nuclear magnetic resonance measurements according to a first embodiment;

[0098] FIG. 4 schematic axial cuts through susceptibility matched containers for high-resolution nuclear magnetic resonance measurements according to a first embodiment (a) and according to a second embodiment including further sealing/retaining elements and an expansion compensation volume.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0099] FIG. 1 shows an axial cut through a typical high resolution NMR setup. The NMR sample 1 in the form of a cylindrical glass tube containing the liquid sample is held in the actual NMR probe head 5. In the probe head 5 the actual NMR irradiation/detection coils 3 are mounted and typically surrounded above and below by radio-frequency shields 2. Further in the probe head and/or in an NMR probe head mounting 7 or in an interior part of the actual magnet, so beyond the actual warm magnet bore 6, there can be additional coils et cetera for the shim.

[0100] The direction of the magnetic field 10 is along a vertical axis in the setup, and the magnetic centre in an axial direction is indicated by the horizontal line 4. This line is typically in the vertical centre of the corresponding coil arrangement 3. The coils 3 define a volume of interest 9, this volume of interest includes the detection volume but also goes further above and further below and even extends radially outside of the actual coils, and this is the magnetic field homogeneity relevant volume because it is covered by the radio-frequency field of the coils. It is this volume of interest 9, where magnetic homogeneity is of utmost importance to achieve high signal-to-noise ratios and to avoid distortions. This volume of interest 9 is where the proposed compound is of particular use, because its magnetic volume susceptibility is adapted to the magnetic volume susceptibility of the actual sample, which in effect means that the change in magnetic volume susceptibility felled by the coils in irradiation and/or detection is homogeneous to a maximum extent and is not influenced by magnetic volume susceptibility changes in a spatial dimension. This volume of interest is typically extending along the B field direction 50% above and below in length of the actual detection active volume 12, which is normally defined by the axial height of the saddle or solenoid coils 3.

[0101] This is further illustrated in FIG. 2, where the volume of interest 9, is shown in relation with the detection active volume height 12, the actual detection active volume is the space enclosed by the coils 3 along this height 12. The liquid column typically has a height which is 50% above and below the active volume height 12, and this essentially defines the height of the volume of interest 9. In a radial direction typically the volume of interest, which is defined by a circular cylinder in case of saddle coils, extends 50% beyond the diameter of the coils on each radial side.

[0102] The compound as proposed in this application can be used in this volume of interest 9 essentially without disturbing the magnetic volume susceptibility conditions as defined by the magnetic volume susceptibility of the actual sample.

[0103] The proposed compound in the form of a PTFE/Cr.sub.2O.sub.3 compound can for example be obtained as follows:

[0104] Weigh 10 kg PTFE (99% purity, grain size 10-30 um (d50))+14 gr Cr.sub.2O.sub.3 (99.9% purity, grain size 1-20 um (d50)) into a drum; cool down to ?15? C. for at least 24 hours; pre-mix and re-mix with mixing aggregate; pour the mixture into an appropriate mould; press with 300 kg/cm.sup.2, holding time 3 minutes, slowly reduce pressure; demould, then degas for at least 12 hours; sintering at max. 365? C.

[0105] The resulting material can be machined to any kind of desired shape using standard machining technology. In particular it is possible to machine the required elements for sample holder as will be discussed further below.

[0106] The resulting material has a magnetic volume susceptibility of ?9.03*10.sup.?6 (SI), which is matched to the magnetic susceptibility of a typical sample of water which is in the same range.

[0107] FIG. 3 schematically illustrates an NMR tube which is made from such a compound. The NMR tube, in contrast to a conventional glass tube where the cavity extends to the very bottom, in this case in the lower portion 20 is solid in the compound, so does not comprise a cavity for the actual sample. The cavity for the actual sample is restricted to the cavity portion 21, which is then covered by a plug made of the same compound. While such a setup would lead to inacceptable steps in the magnetic volume susceptibility at the interface between the lower portion to the cavity 21, and at the interface between the cavity 21 to the plug 13, leading to loss in signal-to-noise and sensitivity, due to the magnetic volume susceptibility matching of the proposed compound material no such steps are present and the signal-to-noise ratio and the sensitivity can be maintained in spite of having a much smaller sample volume allowing for higher concentration or smaller volume of the actual substance to be analysed for a given amount of available actual substance.

[0108] FIG. 4 illustrate two different embodiments of such a sample holder. In a) an embodiment is shown, where, in contrast to FIG. 3, there is no simple cylindrical plug 13, but there is a shaped 17, only the lowermost portion of which penetrates into the upper part of the cavity 12 for sealing. This 17 can be fixedly attached to the lower portion of the sample holder, or it can be removable to allow filling and emptying of the container. Also it is possible to make such a device in one piece, for example if additive manufacturing is used.

[0109] If the 17 is fixedly attached to the lower portion of the container, it is useful to have a narrow filling/emptying channel 16, which should have a diameter small enough to avoid any interference of that liquid portion with the measurement. On top the corresponding device can be closed by a septum 15.

[0110] FIG. 4b) illustrates another embodiment where the 17 is further sealed by corresponding sealing elements 19, for example O-rings, to the lower portion of the container. In addition to that, above the channel 16 a small volume 18, largely outside of the detection space of the coils, can be provided to compensate for temperature and/or pressure induced volume changes of the sample.

LIST OF REFERENCE SIGNS

[0111]

TABLE-US-00002 1 NMR sample 2 radiofrequency shields 3 NMR irradiation/detection coil 4 magnetic centre in axial direction 5 NMR probe head 6 warm magnet bore 7 NMR probe head mounting 8 NMR tube 9 volume of interest, detection and magnetic field homogeneity relevant volume 10 direction of magnetic field, Z direction, B.sub.0 11 liquid column in 8, typically 40 mm axial length 12 detection active volume height, typically 20 mm axial length 13 plug of magnetic volume susceptibility matched material 14 container of magnetic volume susceptibility matched material 15 septum 16 filling/emptying channel 17 cap 18 thermal expansion compensation volume 19 sealing/retaining element 20 lower solid material portion 21 cavity portion 22 upper solid material portion