JP2003329754A - Fixing structure of solid sample measuring probe used for nuclear magnetic resonance measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure of a solid sample measuring probe capable of fixing a solid sample measuring probe of a nuclear magnetic resonance (NMR) measuring apparatus to an original position again. <P>SOLUTION: The fixing structure of a solid sample measuring probe used for the NMR apparatus is provided with a probe body comprising an upper support plate, an upper fixing screw, a probe, a probe movable guide post, a stopper, a lower support plate, a lower part fixing screw, a pedestal, and a probe lower pedestal support plate. The probe lower pedestal support plate is provided below the lower part support plate parallel to it, and the lower support plate and the probe lower pedestal support plate are connected together with the pedestal incorporating an elastic body. So, the probe lower pedestal support plate can be vertically moved relative to the floor surface while contacting to an NMR apparatus installation floor surface, and the height of the upper support plate can be adjusted through the elastic body with less impact when fixing the upper support plate to a fixing plate of the NMR apparatus body. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structure for fixing a sample measuring probe (hereinafter referred to as a probe) for detecting a nuclear magnetic resonance signal in a nuclear magnetic resonance measuring apparatus (hereinafter abbreviated as an NMR apparatus). Relates to a structure for fixing a probe support plate to a probe fixing plate provided at a probe mounting port of an NMR apparatus.

[0002]

2. Description of the Related Art At the center of the magnetic field of the measuring section of an NMR apparatus,
A removable detection device called a probe is provided. A probe is a detector that measures the magnetic moment of the nucleus of a chemical substance.A sample tube containing the chemical substance is attached to the probe, and a strong magnet is used for measurement.Therefore, it is necessary to fix the probe in a location where there is no magnetic field bias. is there.

The probe is unique to each NMR apparatus, and the structure thereof varies depending on the type of the NMR apparatus, but normally, a vertical cylindrical space for inserting a sample tube for measurement,
Two sets of compressed air supply circuits, fixing parts for fixing the probe to the magnetic field of a pair of magnets, RF transmitting and receiving coils, LF coils, decoupling coils, and corresponding RF circuits and LF circuits. It consists of conductors, shim coils, and RF preamplifiers. However,
The shim coil may be mounted in the magnetic field separately from the probe. Further, in the solid sample measuring probe, the sample rotating part is a particularly important component. When measuring a solid sample, cancel the dipole interaction in the solid sample,
In order to sharpen absorption, in principle 54.7 degrees (commonly called magic angle) with respect to the vertical magnetic field direction.
The measurement must be performed at an angle of .theta., And the angle (54.7 degrees). +-. 0.025 degrees must always be maintained accurately.

FIG. 1 is a schematic diagram of a probe fixing structure in a conventional general NMR apparatus, and FIG. 2 is a schematic diagram of a probe fixing structure in the conventional apparatus. The probe 8 is composed of a tubular body, an upper support plate 2, a lower support plate 5, and a probe movable guide column 6. The upper support plate 2 has two upper fixing screws 3 and the lower support plate 5 has a lower fixing screw. 9 is 3
Individually deployed. In a conventional general NMR apparatus, a superconducting magnet 20 is provided in an apparatus main body 19, a magnetic field space 21 of the superconducting magnet is formed in a vertical direction, and a probe 8 is inserted and fixed in this magnetic field space during measurement. To do. At the upper end of the apparatus main body 19, there is provided a hole that serves as an insertion port 22 for a sample tube when a solution probe is attached and serves as an air exhaust port 22 when a solid probe is attached.

When mounting the probe 8, the upper support plate 2 is butted against the fixed plate 1 below the superconducting magnet 20, and then the upper fixing screw 3 of the upper support plate 2 is screwed into the fixed plate screw hole 4. As a result, the probe 8 is fixed to the lower portion of the superconducting magnet 20 and is suspended. Next, the three lower fixing screws 9 provided on the lower support plate 5 are pressed against the floor surface to be completely attached. As described above, in the conventional probe main body fixing structure, a structure in which the probe is attached to the NMR measurement unit of the NMR apparatus and fixed by the screw has been adopted.

In the NMR measurement, ^first , ¹ H was used for a standard sample.
Or ¹³ C-NMR is measured, the resolution and the sensitivity are adjusted from the NMR spectrum, and then the probe is replaced to measure the sample. Therefore, if the mounting position is slightly different before and after the replacement of the probe, the uniformly adjusted magnetic field is biased and the measured spectrum is disturbed. However, readjustment of the magnetic field is not simple,
Adjusting the magnetic field to satisfy all of these is not easy. In addition, slight vibration due to attachment / detachment and replacement of the probe, and impact on the precision parts in the probe due to impact cause disturbance in the measured spectrum, resulting in deterioration of the resolution (sensitivity) and sensitivity of the measured spectrum. Furthermore, depending on the degree of impact during probe replacement, measurement may not be possible. Furthermore, in the solid sample measuring probe, a particularly important part is a sample rotating part, and in order to cancel the dipole interaction in the solid sample and sharpen the absorption, the magic angle (54.7) is always accurate. Every time)
± 0.025 degrees must be maintained, and if it deviates from the angle range, measurement cannot be performed. Furthermore, the fixed position of the probe may change, which may make attachment of the probe difficult. Therefore, after replacing the probe, it is difficult to obtain reproducible measurement data, and there is a problem that it may cause a failure.

Further, in the NMR measurement of a solid sample,
Although the angle was often shifted before and after probe replacement due to the effects of vibration and shock when the probe was replaced, improvements to the device to eliminate this effect have not been made particularly in the past, and accurate measurement is not possible. Had to adjust the angle precisely over the next few hours.

Japanese Patent Laid-Open No. 2000-292515 discloses that
A fixing structure for accurately mounting a solution sample probe is disclosed. This is a method in which the fixing plate and the supporting plate are fixed by the knob and the coupling hole, and after the fixing by the knob and the coupling hole, the fixing plate and the supporting plate are accurately aligned by the optical code detecting element. .

[0009]

However, the probe fixing structure disclosed in Japanese Patent Laid-Open No. 2000-292515 is
This is a fixed structure for mounting the solution sample probe with high accuracy, and although the liquid sample probe can be mounted accurately and quickly, no measures have been taken against the vertical fluctuation and impact of the probe during mounting. On the other hand, the fixed structure of the probe for the solid sample must maintain the magic angle strictly, so the allowable range of vibration and damage when exchanging the probe is very strict, therefore,
It is difficult to apply the probe fixing structure for a liquid sample disclosed in Japanese Patent Laid-Open No. 2000-292515 to the probe fixing structure for a solid sample.

The probe fixing structure of the present invention solves the above-mentioned problems and does not require readjustment of the magic angle before and after replacement of the solid sample measuring probe, and the probe can be returned to its original position without vibration or impact. An object of the present invention is to provide a probe fixing structure for measuring a solid sample in an NMR apparatus that can be accurately and quickly returned to the above.

[0011]

SUMMARY OF THE INVENTION The present invention has the following aspects.

(1) A structure in which an upper support plate of a solid sample measuring probe used in an NMR apparatus is fixed to a fixed plate of an NMR apparatus main body, and the upper support plate, an upper fixing screw, a probe, a probe movable guide column, a stopper, A probe main body including a lower support plate, a lower fixing screw, a pedestal, and a probe lower pedestal support plate has a probe lower pedestal support plate installed below the lower support plate in parallel with the lower support plate. A structure for fixing a probe for measuring a solid sample used in an NMR apparatus, characterized in that a support plate and a support plate for supporting the lower part of the probe are connected by a pedestal containing an elastic body.

(2) The elastic body is a stainless steel spring, and two springs are provided for each pedestal,
A probe for measuring a solid sample used in an NMR apparatus according to (1), characterized in that the length of the spring is a length that interpolates the height of the pedestal and satisfies a shrinkage margin that exerts a spring effect. Fixed structure.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The probe fixing structure of the present invention relates to a fixing structure for a solid sample measuring probe, but it can also be used as a fixing structure for a liquid sample measuring probe. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a schematic view of the probe fixing structure of the present invention, and FIG. 4 shows the fixing structure of the solid sample measuring probe of the present invention. In the probe fixing structure of the present invention, the fixing between the upper fixing plate for fixing the solid sample measuring probe and the lower supporting plate of the probe is performed through a component that absorbs a shock during mounting. Is a probe lower pedestal support plate provided in parallel with the lower probe support plate,
Since both are connected by a pedestal containing an elastic body, there is little vertical fluctuation when the probe is fixed, and the impact can be absorbed by the elastic body. Unlike the conventional fixing structure shown in FIG. 1, the probe fixing structure of the present invention has little vertical fluctuation of the probe when mounted directly under the magnet, and the damage to the probe is significantly reduced.

According to the structure of the probe fixing structure of the present invention, the probe 8 has a tubular body, an upper support plate 2, a lower support plate 5,
And a movable probe support column 6, and the upper support plate 2 is provided with two upper fixing screws 3 and the lower support plate 5 is provided with three lower fixing screws 9. Further, below the lower support plate 5, parallel to the lower support plate 5, the probe lower pedestal support plate 10 is provided.
Is provided, and the lower support plate 5 and the probe lower pedestal support plate 10 are connected via a pedestal 11. Elastic body 1
Since the lower support plate is pressed against the floor surface through the pedestal 11 having the built-in 5, the probe main body can be vertically moved up and down without giving an unreasonable inclination, and the probe main body is fixed on the floor surface by the probe lower pedestal support plate 10. Since it can be done in contact with each other, it can be attached without giving shock or vibration to the probe body.

FIG. 5 shows an example of the pedestal used in the present invention. The pedestal 11 used in the present invention is preferably made of a non-magnetic material for the pedestal constituting member and screws so that it can be used under a magnetic field without any influence. Specifically, aluminum is preferable, and stainless steel, titanium and the like can also be used.

The width and depth of the pedestal are preferably such that they do not affect the curvature and depth of the inner diameters of the lower support plate 5 and the probe lower pedestal support plate 10.
In the MR device, the width is about 40 mm and the depth is 3 mm.
Around 0 mm is preferable. Further, the height of the pedestal is preferably such that the vibration received by the probe is minimized, and in a general NMR apparatus, the height is preferably around 20 mm. The material and shape of the elastic body that is the pedestal constituent member is
A material and a shape that can suppress the influence on the magnetic field as much as possible and can withstand repeated use are preferable, and a stainless steel spring is particularly preferable. In order for the spring to operate stably, it is preferable that at least two springs are attached to one pedestal, and the length of the spring is
It is necessary to have a length that interpolates the height of the pedestal and that satisfies the shrinkage margin in which the spring exerts its effect. The diameter of the spring is not particularly limited, but the diameter is preferably about 5 to 15 mm. FIG. 6 shows a detailed view of the pedestal mounting position of the present invention. The number of the pedestals is preferably three, and the pedestals are mounted at an angle where the lower support plate can be stably held horizontally with respect to the floor. Specifically, one of the three pedestals is installed on the probe lower pedestal support plate 10 at an equal distance from the probe movable guide column 6, and the remaining two pedestals are centered in the magnetic field space with respect to the one pedestal. Are attached to the probe lower pedestal support plate 10 so that the angles are 120 degrees relative to each other.

In the procedure for fixing the probe of the present invention, as shown in FIG. 3, the probe main body, which was at the height shown in A before being fixed, is pushed down to the height shown in B. The height of the probe body shown in A, which is the normal state before fixation, is such that the height from the floor surface to the upper end of the probe body, that is, the upper support plate 2 is several millimeters higher than the height from the floor surface to the fixation plate 1. It is in. next,
After moving the probe directly below the magnetic field space 21, the probe is returned to the height shown in C, that is, the same height as A. By returning the probe main body to the height shown in C again, the upper support plate 2 and the upper fixing screw 3 are pressed against the fixing plate 1, and the upper fixing screw 3 is screwed into the fixing plate screw hole 4 to easily fix it. The probe body can be attached to the plate 1. From the A position to the B position and the C position, the probe is moved to the lower part of the magnet with almost no vertical movement. Then, the three lower fixing screws 9 provided on the lower support plate 5 are pressed against the probe lower pedestal support plate 10 to be completely attached.

FIG. 7 shows an example of a probe up-and-down moving mechanism based on the pedestal of the present invention. The position A indicates the case where the probe main body is lowered, and the position B indicates the case where the probe main body is raised.
As a result of securing a change margin of 5 mm with the movable spring, the lower support plate 5 of the probe body can be moved smoothly and in good balance. Therefore, the probe has no vibration or damage.

[0021]

EXAMPLES Example 1 Aluminum phosphate was used as a sample, and the solid sample measuring probe fixing structure shown in FIG. 7 with the pedestal shown in FIG. 5 was used. The magic angle before the probe exchange was 54.70 degrees, and after the probe exchange, the ²⁷ Al NMR spectrum of the sample was measured without adjusting the magic angle. Using a 7.04 T NMR apparatus, the resonance frequency was 78.172 MHz, the spectrum width during measurement was 40,000 Hz, the pulse width was 4 microseconds, the repetition time was 1 second, and the integration was performed 64 times.
Further, using the conventional probe fixing structure shown in FIG. 1, the same sample and conditions as in this example were used to analyze ²⁷ Al NMR.
The spectrum was measured. Spectra of ²⁷ Al by the probe fixing structure of the present invention in FIG. 8 (Example 1) shows the spectrum of ²⁷ Al according to the conventional fixing structure (Fig. 1) (Comparative Example 1).

The magic angle before replacing the probe is 54.71 degrees when the fixing structure of the present invention is used, and there is no deviation in the angle before and after replacement, the baseline is stable, and the measurement result is quantitative. Although a spectrum that could be analyzed with good accuracy was obtained, on the other hand, when the conventional fixed structure was used, the angle was 54.65 degrees, and a shift occurred before and after replacement, the baseline waviness, and the obtained result was The spectrum was difficult to analyze and non-quantitative. Therefore, the fixing structure of the present invention is
It is clear that the magic angle can be kept stable compared to the conventional fixed structure.Because the magic angle is accurately attached to the position before removal, there is no reduction in resolution or sensitivity and readjustment time is increased. It can be said that it is possible to perform highly accurate NMR measurement without the need. (Embodiment 2) Using the same probe fixing structure for measuring a solid sample according to the present invention as in Embodiment 1 (Example 2) and the conventional fixing structure (Comparative Example 2), the change in the magic angle due to probe exchange is measured. did. The initial magic angle before probe replacement was 54.70 degrees. FIG. 9 shows the change in the magic angle when the replacement is performed 20 times.

In the case of the fixing structure of the present invention, the operation for attaching and detaching the probe hardly gives shock or vibration which is considered to be a cause of deterioration of resolution or sensitivity or failure, so that the magic angle should be almost changed. However, it is clear that no adjustment is required after replacement / installation. On the other hand, in the case of the conventional fixed structure, the change in the magic angle is large, and it is clear that readjustment is necessary each time the probe is replaced / installed.

In the present invention, no matter how many times the probe is exchanged, there is no vibration or damage to the probe, the magic angle does not change, measurement can be performed immediately after attachment, and the time required for probe exchange can be shortened. .

The solid probe replacement work is four works of setting a reference point, removing the solution probe, attaching the solid probe, and adjusting the magic angle. When the conventional probe fixing structure shown in FIG. 1 was used, the average time required for the replacement work was about 175 minutes. On the contrary, when the solid sample measuring probe fixing structure shown in FIG. 7 with the pedestal shown in FIG. 5 of the present invention is used, the average time required for the replacement work is about 9 minutes, and the replacement is drastically changed. I saved time.

[0026]

The fixation of the NMR probe for a solid sample is very complicated and often gives vibrations or damages to the probe, and the replacement work takes a very long time. If you use the fixed structure of the probe for
Since the exchange work is significantly shortened and the magic angle does not change, highly accurate solid-state NMR measurement can be easily and continuously performed.

[Brief description of drawings]

FIG. 1 is a schematic view of a conventional commercially available probe body.

FIG. 2 is a schematic view of a conventional probe fixing structure.

FIG. 3 is a schematic view of a probe fixing structure of the present invention.

FIG. 4 is a schematic view of a probe main body of the present invention.

FIG. 5 is a diagram showing an example of a pedestal of the probe fixing structure of the present invention.

FIG. 6 is a diagram showing a pedestal mounting position of the present invention.

FIG. 7 is a diagram showing a probe up-and-down moving mechanism based on a base of the probe of the present invention.

FIG. 8 is a diagram showing an NMR spectrum of ²⁷ Al.

FIG. 9 is a diagram showing a change in magic angle for each probe replacement.

[Explanation of symbols]

1 ... Fixing plate 2 ... Upper support plate 3 ... Upper fixing screw 4 fixing plate screw holes 5 ... Lower support plate 6… Probe movable guide column 7 ... Stopper 8 ... Probe 9 ... Lower fixing screw 10 ... Probe lower base support plate 11 ... Pedestal 12 ... Lower support plate fixing plate 13 ... Lower support plate fixing plate set screw 14 ... Lower support plate receiver 15 ... Movable spring, elastic body 16 ... Movable lower support plate receiving stand 17 ... Movable lower support plate receiving set screw 18 ... Set screw for receiving lower movable support plate 19 ... Device body 20 ... Superconducting magnet 21 ... Magnetic field space 22 ... Sample insertion port, air exhaust port

Claims (2)

[Claims] 1. A structure for fixing an upper supporting plate of a solid sample measuring probe used in a nuclear magnetic resonance measuring apparatus to a fixing plate of a main body of the nuclear magnetic resonance measuring apparatus, the upper supporting plate, an upper fixing screw, a probe, and a movable probe. The probe main body including the guide column, the stopper, the lower support plate, the lower fixing screw, the pedestal, and the probe lower pedestal support plate has the probe lower pedestal support plate installed below the lower support plate and in parallel with the lower support plate. Further, the lower support plate and the probe lower pedestal support plate,
A structure for fixing a probe for measuring a solid sample used in a nuclear magnetic resonance measuring apparatus, which has a structure in which elastic bodies are connected by a pedestal. 2. The elastic body is a stainless steel spring, two springs are provided for each pedestal, and the length of the spring interpolates the height of the pedestal and exerts a spring effect. The fixed structure of the probe for measuring a solid sample used in the nuclear magnetic resonance measuring apparatus according to claim 1, wherein the fixing structure has a length that satisfies the shrinkage allowance.