RU201791U1 - A HIGH-PRESSURE CELL FOR REGISTRATION OF NUCLEAR MAGNETIC RESONANCE SPECTRA AT SUPERCRITICAL STATE PARAMETERS - Google Patents

Abstract

The utility model relates to the technological support of an NMR spectrometer and can be used on various types of instruments equipped with sensors for recording with an inner diameter of 5 mm as a device for carrying out nuclear magnetic resonance experiments under pressures up to 300 bar. at supercritical state parameters, containing a sapphire ampoule fixed in the ampoule holder, mated to the inlet port and the connector by means of a threaded connection, while it contains a threaded hole 2.00-2.10 mm in diameter with a conical seal for entering a high-pressure capillary. the solution allows you to control fluctuations in the critical density of the solvent during the NMR experiment and, as a result, to increase the signal-to-noise ratio. Equipping the high-pressure cell with a threaded hole for capillary inlet allows increasing the signal-to-noise ratio by increasing one magnetic field homogeneity due to the control of fluctuations in the critical density of the solvent.

Description

The utility model relates to the technological support of an NMR (nuclear magnetic resonance) spectrometer and can be used on various types of instruments equipped with sensors for registration with an inner diameter of 5 mm as a device for carrying out nuclear magnetic resonance experiments under pressure up to 300 bar.

A similar useful model for carrying out NMR experiments is known - a cell for performing spectral measurements by nuclear magnetic resonance spectroscopy when rotating a sample of a substance at a magic angle (Pat. 2472139 Russian Federation, IPC G01N 24/08 Cell for performing spectral measurements using nuclear magnetic resonance spectroscopy during rotation sample of a substance at a magic angle / Kolyagin Yu.G., Kasyanov I.A., Ivanova I.I .; No. 2011133931/28; application; 15.08.2011; publ. 10.01.2013; bull. No. 1) Cell for the implementation of spectral measurements by nuclear magnetic resonance spectroscopy with the rotation of a sample of a substance at a magic angle, which has axial symmetry, is made in the form of two cylindrical glasses with hermetically sealed lids, installed one in the other without a gap between them, while the inner glass containing the sample of the substance and the corresponding the cover is made of a non-metallic material resistant to aggressive medium at pH 0-14, and the outer glass and the corresponding lid are made of a non-metallic material with rigidity and temperature coefficient of expansion, ensuring the preservation of the shape and integrity of the external structure in the temperature range from -20 ° C to 250 ° C and pressure up to 15 atm. The inner glass and the corresponding lid are made of fluoroplastics, chemically resistant plastics or ceramics, the outer glass and the corresponding lid are made of polyether ketone, polyamidimide, polybenzimidazole, or ceramics, the diameter of the lower part of the inner glass lid entering the glass corresponds to the inner diameter of the said glass, and the diameter of the upper part of the lid of the inner cup is equal to the outer diameter of the said cup, the inner cup is hermetically connected to the lid by soldering, the inner cup is hermetically connected to the lid by means of an O-ring placed in a circular groove made in the lower part of the lid, the sealed connection of the outer cup to its lid is made with an adhesive method, mainly with the help of epoxy glue, the hermetic connection of the outer glass to its lid is made by a threaded method, the hermetic connection of the outer glass to its lid is made using sealing rings.

The disadvantages of the cell are: limitation on the used pressure, which, of course, imposes serious restrictions on the variety of measurements performed. For example, even supercritical carbon dioxide, which has relatively low critical pressure and temperature parameters (7.38 MPa and 31 ° C), cannot be used as a solvent in a given cell. In addition, the rotation of the cell at a magic angle is an obstacle to monitoring and maintaining the pressure parameter in real time, and its variation is possible only by changing the temperature, which is very unreliable due to the lack of a way to monitor the pressure in real time. The maximum temperature maintained in the NMR cell - 250 ° C, declared in the materials of the patent, is excessive, since in most commercial spectrometers there is a temperature limit of 90 ° C - 100 ° C. In the case of preliminary heating of the sample, followed by placing the cell in the NMR spectrometer sensor and recording the spectra, a temperature gradient will inevitably arise, which will be a serious hindrance to the qualitative registration and interpretation of NMR spectra. In addition, such a cell assumes the presence of a special sensor for registration of spectra, which will maintain mechanical rotation and balancing of the cell. Analysis of the patent materials shows that the cell cannot meet the modern requirements for high-pressure NMR experiments, and its use in this area is not justified.

The closest analogue to the claimed utility model is a high pressure cell for use in NMR spectroscopy patented in 1996 (US 6,362,624 B1, Apparatus and method for high pressure nmr spectroscopy / Andrew J. Wand, Mark R. Ehrhardt, Jeffrey L. Urbauer, Appl . No .: 09 / 428,084). This utility model belongs to the field of NMR spectroscopy, namely, it is a device for performing high-resolution NMR experiments. This device is especially useful for determining the molecular structure and dynamics of proteins and protein complexes. The cell is a high-pressure chamber for use in NMR spectroscopy, including a sapphire sampling tube (sapphire ampoule) for material placement. The sampling tube is made of a material that can withstand high pressure, suitable materials for the sampling tube include, but are not limited to, sapphire, zirconium oxide, and quartz. In a preferred embodiment, the sample tube is made of sapphire, the inner opening of the tube (sapphire ampoule) has the same diameter as the inner opening of the cap (connector), the sampling tube (sapphire ampoule) is closed at one end and has a main section and a flange at the open end. made of titanium alloy, bonded with a one-component epoxy adhesive. Sample tube holding body (ampoule holder and inlet port) is a stepped cylindrical tube made of non-magnetic metal with high tensile strength, suitable materials for the body (ampoule holder and inlet port) include, but are not limited to, stainless steel, titanium alloys and beryllium-copper alloys. The body (ampoule holder and inlet port) has a wide upper section (inlet port) and a narrow lower section (ampoule holder), the upper section has an internal threaded borehole for fixing the cover (connector) to close the body (inlet port), the lower corners of the section (inlet port) port) have a two-stage edge, the lower stage has an O-ring manufactured by Al Xander (Bowmansville, NY), which provides a reliable seal between the lid (connector) and the upper section (inlet port), the lower section (ampoule holder) has a flat surface or collar, which serves as a sealing surface for the sampling tube (sapphire ampoule), also a washer (o-ring) installed on the collar, which provides a seal between the body (ampoule holder and inlet port) and the sampling tube (sapphire ampoule). The lid with an inlet (connector) is made of the same material as the cell body (ampoule holder and inlet port) and has a threaded connection with the cell body (ampoule holder and inlet port); in addition, the cell contains means for sealing the connector and an inlet port (connector seal) and means for sealing the ampoule holder and sample tube (ampoule seals). The operating pressure during cell use is 5000 psi (345 bar).

The disadvantages of the cell are:

- The impossibility of monitoring the pressure in the cell in real time, which is an important condition both for experiments with different state parameters (temperature and pressure) and constant parameters, which lead to significant fluctuations in the critical density of the solvent and low uniformity of the magnetic field inside the cell.

Analysis of the patent materials shows that the use of this cell is extremely ineffective, and this drawback inevitably leads to a decrease in the signal-to-noise ratio.

The technical result of the utility model is a new design of a high-pressure cell, the use of which makes it possible to control fluctuations in the critical density of the solvent and, as a consequence, to increase the signal-to-noise ratio in experiments on nuclear magnetic resonance by increasing the uniformity of the magnetic field.

The specified technical result is achieved by the fact that a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical parameters of state, containing a sapphire ampoule fixed in the ampoule holder, coupled with the inlet port and the connector by means of a threaded connection, according to the utility model, is equipped with a threaded hole with a diameter of 2 , 00-2.10 mm with cone seal for high pressure capillary entry.

The technical solution makes it possible to control fluctuations in the critical density of the solvent during the NMR experiment and, as a consequence, to increase the signal-to-noise ratio.

Equipping the cell with a threaded hole 2.00-2.10 mm in diameter with a conical seal for introducing a high-pressure capillary made it possible to conduct nuclear magnetic resonance experiments at supercritical state parameters with real-time monitoring of the pressure in the cell. This technical solution allows you to control the natural slight decrease or increase in pressure and, as a result, has a positive effect on minimizing fluctuations in the critical density of the solvent and the signal-to-noise ratio.

Thus, the features of a utility model can achieve the claimed technical result.

The utility model is illustrated by drawings.

FIG. 1 shows a 3D model of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical parameters of state in a ready-to-use form.

FIG. 2 shows a 3D model of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical parameters of state in a longitudinal section.

FIG. 3 shows a drawing of an inlet port as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters.

FIG. 4 shows a drawing of the inlet port as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters (top view).

FIG. 5 shows a drawing of an ampoule holder as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters.

FIG. 6 shows a drawing of an ampoule holder as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters (top view).

FIG. 7 shows a drawing of a connector with a threaded hole 2.00-2.10 mm in diameter with a conical seal for introducing a high-pressure capillary as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters.

FIG. 8 shows a drawing of a connector as a structural component of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical state parameters (top view).

The high-pressure cell contains a high-pressure ampoule made of synthetic sapphire single crystal 1 (Fig. 1, Fig. 2) having the following parameters: outer diameter - 5 mm, inner diameter - 3 mm, total length - 87 mm, the flange of the ampoule has a diameter - 8 mm and a height of 7 mm. The ampoule is fixed in the ampoule holder 2 (Fig. 1, Fig. 2, Fig. 5, Fig. 6), made of high-quality heat-strengthened aviation duralumin - D16T, which, in turn, is connected to the inlet port 3 (Fig. 1, Fig. . 2, Fig. 3, Fig. 4), also made of high-quality heat-strengthened aviation duralumin - D16T, the ampoule is filled through a special capillary fixed in the connector 4, with a threaded hole 2.00-2.10 mm in diameter with a conical seal for insertion high-pressure capillary (Fig. 1, Fig. 2, Fig. 7, Fig. 8), made of heat-resistant stainless steel, resistant to aggressive media - AISI 316L. To achieve the best tightness inside the cell body and to minimize pressure changes during the experiment, the O-ring of the connector was made of Teflon 5 (Fig. 2), the O-ring of the ampoule 6 (Fig. 2) was made of silicone rubber resistant to CO ₂ , and also a sealing ring of the ampoule made of caprolon 7 (Fig. 2).

Assembly of a high-pressure cell for recording nuclear magnetic resonance spectra at supercritical parameters of state.

On the high-pressure ampoule 1 (Fig. 1, Fig. 2) under the flange is the sealing ring of the ampoule made of caprolon 7 (Fig. 2), then the high-pressure ampoule is placed in the ampoule holder 2 (Fig. 1, Fig. 2, Fig. 5 , fig. 6). A pre-assembled assembly from the inlet port 3 (Fig. 1, Fig. 3, Fig. 4), connector 4 with a threaded hole 2.00-2.10 mm in diameter with a conical seal for introducing a high-pressure capillary (Fig. 1, Fig. 2, Fig. 7, Fig. 8) and the O-ring of the Teflon connector 5 (Fig. 2), through the O-ring of the ampoule 6 (Fig. 2), made of silicone rubber resistant to CO ₂ , is connected to the high-pressure ampoule by means of a threaded connection 1 (Fig. 1, Fig. 2), previously located in the ampoule holder 2 (Fig. 1, Fig. 2, Fig. 5, Fig. 6). This screw connection is tightened with an open-end torque wrench with a tightening torque of 9 N * m. To control the quality of the assembly, the assembled cell for recording nuclear magnetic resonance spectra at supercritical state parameters is pressurized, and possible leaks are checked using a leak detector (for example, Ion Science GasCheck 5000is).

The cell works as follows.

Using an external source of high pressure (manual press or electric high pressure pump) into an assembled cell consisting of a high pressure ampoule 1 (Fig. 1, Fig. 2), made of a synthetic sapphire single crystal, ampoule holder 2 (Fig. 1, Fig. . 2, Fig. 5, Fig. 6), inlet port 3 (Fig. 1, Fig. 2, Fig. 3, Fig. 4) and connector 4 with a threaded hole 2.00-2.10 mm in diameter with a conical seal for introducing a high capillary pressure (Fig. 1, Fig. 2, Fig. 7, Fig. 8), previously placed in the safety box and filled with the test sample. Through a capillary securely fixed to the connector 4 (Fig. 1, Fig. 2, Fig. 7, Fig. 8) the required solvent is supplied at a given pressure, which through the adjacent channel of the inlet port 3 (Fig. 1, Fig. 2, Fig. 3, Fig. 4) and the ampoule holder 2 (Fig. 1, Fig. 2, Fig. 5, Fig. 6) falls into the high-pressure ampoule 1 (Fig. 1, Fig. 2). Then the cell with a high-pressure capillary attached to the connector 4 (Fig. 1, Fig. 2, Fig. 7, Fig. 8) is removed from the safety box and immediately placed into the NMR spectrometer sensor, where it is heated for subsequent registration of NMR spectra ... Due to the presence of continuous interaction of the cell with an external source, through a high-pressure capillary fixed in connector 4 with a threaded hole 2.00-2.10 mm in diameter with a conical seal for introducing a high-pressure capillary (Fig. 1, Fig. 2, Fig. 7 , Fig. 8), it is possible to control the pressure during the NMR experiment. At the end of the experiment, the cell is removed from the NMR spectrometer sensor, the cell is decompression, its sequential disassembly, and washing.

Thus, the use of a utility model equipped with a threaded hole for the introduction of a high-pressure capillary with a diameter of 2.00-2.10 makes it possible to carry out NMR experiments at supercritical parameters of state with control of the pressure inside the cell in real time, with a high uniformity of the magnetic field, which, of course, , affects the signal-to-noise ratio. The approbation of the utility model showed that the claimed technical result was achieved, and the signal-to-noise ratio was significantly increased in comparison with the prototype, due to an increase in the uniformity of the magnetic field. The achievement of the technical result is due to the equipment of the cell with a threaded hole for the introduction of a high-pressure capillary with a diameter of 2.00-2.10 mm, which made it possible to control the pressure in the cell in real time, which, in turn, makes it possible to control the natural slight decrease or increase in pressure and, as a consequence, it has a positive effect on the uniformity of the magnetic field and the signal-to-noise ratio.

Claims (1)

A high-pressure cell for recording nuclear magnetic resonance spectra at supercritical parameters of state, containing a sapphire ampoule fixed in the ampoule holder, mated to the inlet port and connector by means of a threaded connection, characterized in that it is equipped with a threaded hole 2.00-2.10 in diameter mm with cone seal for high pressure capillary entry.

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