Method for measuring deuteration rate of heavy water by nuclear magnetic resonance hydrogen spectroscopy

Abstract

The invention relates to a method for measuring the deuteration rate of heavy water by nuclear magnetic resonance hydrogen spectroscopy, which comprises the following steps: S1, weighing 0.03-0.08 g of sodium acetate or potassium acetate solid, adding into a beaker, adding 3-8g of heavy water into the beaker, fully shaking up, and taking the mixed liquid into a nuclear magnetic tube; s2, putting the nuclear magnetic tube into a nuclear magnetic resonance spectrometer, testing at normal temperature, and determining hydrogen spectrum chemical shift and hydrogen spectrum area of the heavy water and the sodium acetate according to a nuclear magnetic hydrogen spectrogram; and S3, quantitatively calculating the deuteration rate in the heavy water. According to a traditional mass spectrometry method, before the deuteration rate of heavy water is detected, heavy water and metal need to react, deuterium gas is generated, and then detection is conducted through high-resolution mass spectrometry, and the process is complex and long in consumed time. Compared with the prior art, the method has the advantages that the heavy water is directly detected by adopting the nuclear magnetic resonance hydrogen spectrum method, additional chemical reaction and gas treatment steps are not needed, and the operation process is obviously simplified, so that the detection efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical analysis, and in particular to a method for measuring the deuteration rate of heavy water by nuclear magnetic resonance hydrogen spectroscopy. Background Art

[0002] As one of the most abundant elements in the universe, the research and application of hydrogen isotopes have shown great value in many scientific and industrial fields. Among them, deuterium (2H or D), as a stable isotope of hydrogen, has become a key material in many scientific research and industrial applications due to its unique physical and chemical properties.

[0003] Deuterium is relatively rare in its natural state, with an abundance of only 0.015 atomic % D, which means that it is quite challenging to directly obtain a high-purity deuterium source in the natural environment. However, it is this rarity that gives deuterium its irreplaceable nature in specific fields. For example, in nuclear magnetic resonance (NMR) analysis, heavy water (D2O), as the basic raw material of the deuterium source, is widely used as a nuclear magnetic solvent because it can significantly reduce the interference of background signals and improve the sensitivity and accuracy of analysis. In addition, in the field of modern agriculture, heavy water is used to study the water absorption and metabolic processes of plants, providing an important tool for water-saving and drought-resistant crop breeding. In the field of biomedicine, compounds labeled with heavy water can be used for drug metabolism and kinetics research, helping scientists better understand the behavior of drugs in vivo. At the same time, heavy water and its derivatives also play an important role as molecular building blocks in the synthesis of new materials, drugs and biomarkers.

[0004] The preparation and purification technology of heavy water is the basis for its wide application. Ordinary water (H2O) is composed of two 1H atoms and one 16O atom, while heavy water (D2O) is composed of two D atoms and one 16O atom. This structural difference leads to significant differences in the physical and chemical properties of heavy water and ordinary water, thus making it possible for its application in various fields.

[0005] However, the deuterium substitution rate of heavy water (i.e. the content ratio of D atoms in heavy water) directly affects its application effect. Therefore, accurate analysis of the deuterium substitution rate of heavy water is not only a key step to ensure its quality, but also an important prerequisite for promoting its in-depth application in the fields of nuclear magnetic solvents, modern agriculture, biomedicine, molecular building blocks, etc.

[0006] Chinese patent CN115266981B relates to a method for determining the deuteration rate of a substance by GC-MS, wherein a certain amount of a sample before deuteration and a sample solution after deuteration to be tested are prepared and tested by GC-MS; the main peaks of the samples before and after deuteration are integrated after deducting the blank, and the ions, response values ​​and abundance percentages of the main peaks are extracted; the main peak ions, response values ​​and abundance percentages before and after deuteration are extracted, and the deuteration rates of the samples are calculated. However, this method is too complicated. If only the deuteration rate in heavy water is measured, the detection efficiency is low using a GC-MS gas chromatograph-mass spectrometer, which is not conducive to practical application.

[0007] In view of the wide application of heavy water in many fields and its unique physical and chemical properties, the efficient and accurate analysis of the deuterium substitution rate of heavy water is not only of great scientific value, but also of significant practical significance. This requires the development of more accurate and efficient heavy water deuterium substitution rate analysis technology to meet the strict requirements of heavy water quality in different fields. Summary of the invention

[0008] In order to overcome the problem of low analysis efficiency in the prior art for determining the deuterium substitution rate in heavy water, the present invention aims to provide a method for determining the deuterium substitution rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy, so as to efficiently and accurately analyze the deuterium substitution rate of heavy water.

[0009] To achieve the purpose of the present invention, the specific technical solutions provided by the present invention are as follows:

[0010] A method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy comprises the following steps:

[0011] S1. Weigh 0.03-0.08g of sodium acetate or potassium acetate solid, add 3-8g of heavy water to the sodium acetate or potassium acetate solid, mix thoroughly, and take the mixed liquid into a nuclear magnetic tube;

[0012] S2. Place the NMR tube in a NMR instrument for testing at room temperature, and determine the hydrogen spectrum chemical shift and hydrogen spectrum area of ​​heavy water and sodium acetate according to the NMR hydrogen spectrum;

[0013] S3. Quantitatively calculate the deuterium substitution rate in heavy water.

[0014] Preferably, the deuterium substitution rate of heavy water is measured in a range of 0.01% to 99.99%.

[0015] Preferably, in step S1, sodium acetate or potassium acetate solid is added to a dry beaker, and then heavy water is added to the dry beaker, and the mixture is thoroughly mixed by ultrasonication.

[0016] Preferably, in step S1, 0.5 mL of the mixed liquid is placed in a nuclear magnetic resonance tube.

[0017] Preferably, in step S2, the resonance frequency of the nuclear magnetic resonance spectrometer is 400 MHz to 800 MHz.

[0018] Preferably, in step S2, the conditions of the nuclear magnetic resonance test are: the quality control does not rotate; the detection temperature is 298.0 (± 0.1) K; the number of empty scans is 4 times; the number of scans is 32 times; the spectrum width is 8000 Hz; the number of sampling points is 65536; the sampling time is 4 seconds; the relaxation delay time is 60 seconds; the excitation center position is δ4.79 (H2Oδ4.76); and the pulse is 90° pulse excitation.

[0019] Preferably, in step S3, quantitative calculation is performed according to formulas (1) and (2):

[0020] The mass of water in the sample is calculated according to formula (1):

[0021]

[0022] The deuterium substitution rate of the sample is calculated according to formula (2):

[0023]

[0024] Among them, m s M is the mass of water remaining in the sample on the machine; W,S is the molar mass of water; M W,Q is the molar mass of the internal standard substance sodium acetate or potassium acetate; H Q is the number of hydrogen atoms corresponding to the quantitative peak of the internal standard substance sodium acetate; H S A is the number of hydrogen atoms corresponding to the water quantitative peak; S A is the integrated area of ​​the water quantitative peak; Q M is the quantitative peak integral area of ​​the internal standard substance sodium acetate; Q M is the mass of the internal standard substance sodium acetate in the sample; s is the mass of heavy water in the sample loaded on the machine; R is the deuterium substitution rate of heavy water.

[0025] The method for determining the deuterium substitution rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy of the present invention has the following beneficial effects:

[0026] 1. Before detecting the deuteration rate of heavy water, the traditional mass spectrometry method needs to react heavy water with metal to generate deuterium gas and then detect it by high-resolution mass spectrometry. This process is not only complicated but also time-consuming. In contrast, the present invention uses nuclear magnetic resonance hydrogen spectroscopy to directly detect heavy water without the need for additional chemical reactions and gas treatment steps, which significantly simplifies the operation process and thus improves the detection efficiency.

[0027] 2. In the mass spectrometry detection process, there may be an incomplete reaction problem, which affects the accuracy and reliability of the test results. However, the present invention uses nuclear magnetic resonance hydrogen spectroscopy to determine the deuterated rate of heavy water, without the need for secondary treatment, avoiding the problem of incomplete reaction, and thus providing more accurate and reliable test results. At the same time, nuclear magnetic resonance technology itself has the characteristics of high precision and high resolution, which further ensures the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the standard H NMR spectrum of the mixed solution in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the preferred embodiments.

[0030] Example 1

[0031] Please refer to Figure 1 This embodiment provides a method for quantitative analysis of chlorosilane by liquid nuclear magnetic resonance, which can mainly include the following steps:

[0032] S1. Take 0.05g of sodium acetate solid and add it to a dry beaker. Then add 5g of heavy water to the beaker, shake well, and take 0.5ml of the mixed liquid into an NMR tube.

[0033] S2. Place the NMR tube in a NMR spectrometer with a resonance frequency of 400 MHZ and test at room temperature. Determine the hydrogen spectrum chemical shift and hydrogen spectrum area of ​​heavy water and sodium acetate according to the NMR hydrogen spectrum. The hydrogen spectrum areas of water and sodium acetate are A and B, respectively. S and A Q ;

[0034] like Figure 1 As shown, Figure 1 The horizontal axis is the hydrogen spectrum chemical shift of water and sodium acetate. Figure 1 The horizontal coordinate 4.58ppm is the hydrogen spectrum chemical shift of water, and the area of ​​this peak is A S ; The horizontal axis 1.69ppm is the hydrogen spectrum chemical shift of sodium acetate, and the area of ​​the peak is A Q .

[0035] S3. Quantitatively calculate the deuterium substitution rate in heavy water according to the following formula: The mass of water in the sample is calculated according to formula (1):

[0036]

[0037]

[0038] The deuterium substitution rate of the sample is calculated according to formula (2):

[0039]

[0040]

[0041] Among them, m s M is the mass of water remaining in the sample on the machine; W,S is the molar mass of water; M W,Q is the molar mass of the internal standard substance sodium acetate or potassium acetate; H Q is the number of hydrogen atoms corresponding to the quantitative peak of the internal standard substance sodium acetate; H S A is the number of hydrogen atoms corresponding to the water quantitative peak; S A is the integrated area of ​​the water quantitative peak; Q M is the quantitative peak integral area of ​​the internal standard substance sodium acetate; Q M is the mass of the internal standard substance sodium acetate in the sample; s is the mass of heavy water in the sample loaded on the machine; R is the deuterium substitution rate of heavy water.

[0042] The principle of the method of determining the deuteration rate of heavy water by nuclear magnetic resonance hydrogen spectroscopy is: the nuclear magnetic resonance spectrometer distinguishes different types of hydrogen according to their different chemical environments; different chemical environments of hydrogen are manifested as different chemical shifts in the standard nuclear magnetic hydrogen spectrum; different concentrations of hydrogen correspond to different areas of nuclear magnetic hydrogen spectrum. Since the chemical environments of hydrogen atoms in heavy water and sodium acetate are different, the chemical shifts in nuclear magnetic resonance are different, so the relative content of water in heavy water in the mixed sample can be quantified according to the corresponding hydrogen areas of heavy water of different concentrations.

[0043] Example 2

[0044] S1. Take 0.03g of sodium acetate solid and add it to a dry beaker. Then add 3g of heavy water to the beaker, shake well, and take 0.5ml of the mixed liquid into an NMR tube.

[0045] S2. Place the NMR tube in a NMR spectrometer with a resonance frequency of 400 MHZ and test at room temperature;

[0046] S3. Quantitative calculation of the deuterium substitution rate in heavy water:

[0047]

[0048]

[0049] Example 3

[0050] S1. Take 0.08g of sodium acetate solid and add it to a dry beaker. Then add 8g of heavy water to the beaker, shake well, and take 0.5ml of the mixed liquid into an NMR tube.

[0051] S2. Place the NMR tube in a NMR spectrometer with a resonance frequency of 400 MHZ and test at room temperature;

[0052] S3. Quantitative calculation of the deuterium substitution rate in heavy water:

[0053]

[0054]

[0055] The above-mentioned method of analyzing the deuterium substitution rate of heavy water by nuclear magnetic hydrogen spectroscopy can quantitatively analyze the deuterium substitution rate of heavy water under the premise of being fast, accurate, convenient, highly sensitive, leaving no residue and not destroying the sample.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy, characterized in that: The following steps are involved: S1. Weigh 0.03-0.08g of sodium acetate or potassium acetate solid, add 3-8g of heavy water to the sodium acetate or potassium acetate solid, mix thoroughly, and take the mixed liquid into a nuclear magnetic tube; S2. Place the NMR tube in a NMR instrument for testing at room temperature, and determine the hydrogen spectrum chemical shift and hydrogen spectrum area of ​​heavy water and sodium acetate according to the NMR hydrogen spectrum; S3. Quantitatively calculate the deuterium substitution rate in heavy water.

2. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: The deuterium substitution rate of heavy water is measured in a range of 0.01% to 99.99%.

3. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: In step S1, sodium acetate or potassium acetate solid is added into a dry beaker, and then heavy water is added into the dry beaker, and the mixture is thoroughly mixed by ultrasonication.

4. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: In step S1, 0.5 mL of the mixed liquid is placed in a nuclear magnetic resonance tube.

5. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: In step S2, the resonance frequency of the nuclear magnetic resonance spectrometer is 400 MHz to 800 MHz.

6. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: In step S2, the conditions of the NMR test are as follows: the quality control does not rotate; the detection temperature is 298.0 (± 0.1) K; the number of empty scans is 4 times; the number of scans is 32 times; the spectrum width is 8000 Hz; the number of sampling points is 65536; the sampling time is 4 seconds; the relaxation delay time is 60 seconds; the excitation center position is δ4.79 (H2Oδ4.76); and the pulse is 90° pulse excitation.

7. The method for determining the deuteration rate of heavy water by hydrogen nuclear magnetic resonance spectroscopy according to claim 1, characterized in that: In step S3, quantitative calculation is performed according to equations (1) and (2): The mass of water in the sample is calculated according to formula (1): The deuterium substitution rate of the sample is calculated according to formula (2): Among them, m s M is the mass of water remaining in the sample on the machine; W,S is the molar mass of water; M W,Q is the molar mass of the internal standard substance sodium acetate or potassium acetate; H Q is the number of hydrogen atoms corresponding to the quantitative peak of the internal standard substance sodium acetate; H S A is the number of hydrogen atoms corresponding to the water quantitative peak; S A is the integrated area of ​​the water quantitative peak; Q M is the quantitative peak integral area of ​​the internal standard substance sodium acetate; Q M is the mass of the internal standard substance sodium acetate in the sample; s is the mass of heavy water in the sample loaded on the machine; R is the deuterium substitution rate of heavy water.

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