Method for determining CO stable isotope abundance percentage content

Abstract

The invention belongs to the technical field of isotope abundance detection, and discloses a method for determining CO stable isotope abundance percentage content. According to the method, detection parameters of the gas isotope mass spectrometer are set, a sample introduction pipeline of the gas isotope mass spectrometer is vacuumized, and then CO gas is introduced into the gas isotope mass spectrometer through the sample introduction pipeline for detection; and calculating the CO stable isotope abundance percentage content according to a detection result. According to the method, the gas isotope mass spectrometer is adopted to detect the < 13 > C isotope abundance in the < 13 > CO and < 12 > CO mixed gas, the sensitivity, the accuracy and the repeatability of a detection result are high through accurate control of the vacuum degree of a pipeline before detection and careful adjustment of detection conditions in the detection process, the detection steps are simple and rapid, the cost is low, and the method is suitable for industrial production. A foundation is laid for optimization of a 12CO and 13CO isotope separation technology, and meanwhile, powerful support is provided for scientific research and related research in the industrial field.

Description

Technical Field

[0001] The invention relates to the technical field of isotope abundance detection, and in particular to a method for determining the abundance percentage of CO stable isotopes. Background Art

[0002] Different atoms of the same element with the same number of protons but different numbers of neutrons are called isotopes. Isotopic molecules of CO include 12 C 16 O. 13 C 16 O. 12 C 18 O. 13 C 18 O, etc. These isotope molecules have a wide range of applications in scientific research. For example, they can be used as important tracers and analytical tools when studying the physical and chemical properties of molecular gases. Their isotope molecules can also be used to study the changes in CO concentration in the earth's atmosphere and the metabolic process of CO in organisms.

[0003] The stable isotopes of C in the CO molecule are 12 C. 13 C two types, 13 C isotopes as tracer atoms have been widely used in various research fields such as life sciences, clinical diagnosis, food safety, ecological environment, new drug development, metabolism, etc. For example, 13 CO gas, as an important starting material, can be used to synthesize a variety of carbon-13 labeled compounds: 13 C-urea is the raw material of the carbon-13 urea breath test kit, which is mainly used in the diagnosis of Helicobacter pylori. It is currently mainly produced by CO low-temperature distillation. 13 CO, specific use 12 CO and 13 The difference in CO volatility can be achieved 12 CO and 13 CO isotope separation, however, the existing isotope separation technology can produce 13 The abundance of C isotope products is low, and the industry has made a variety of technical improvements. 13 The detection of C isotope product abundance is one of the keys to technological improvement.

[0004] Existing 13 There are many methods for detecting the abundance of C isotopes, such as nuclear magnetic resonance, mass spectrometry, and gas chromatography. However, the above detection methods still have problems such as cumbersome detection steps and low detection accuracy. 13 Rapid and accurate detection of the abundance of C isotope products to optimize 12 CO and 13CO isotope separation technology is an issue that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining the abundance percentage of stable isotopes of CO, 13 The detection method of C isotope product abundance has problems such as complicated detection steps and low detection accuracy.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for determining the abundance percentage of stable isotopes of CO, comprising the following steps:

[0008] Setting the detection parameters of the gas isotope mass spectrometer, evacuating the sampling pipeline of the gas isotope mass spectrometer, and then introducing the CO gas into the gas isotope mass spectrometer through the sampling pipeline for detection; calculating the abundance percentage of the CO stable isotope according to the detection results;

[0009] Wherein, the CO gas is 12 CO and 13 CO mixed gas.

[0010] Preferably, in the above method for determining the abundance percentage of stable isotopes of CO, the vacuum degree of the vacuum pumping is 1×10 -5 ~5×10 -5 Pa.

[0011] Preferably, in the above-mentioned method for determining the percentage abundance of stable isotopes of CO, the detection parameters of the gas isotope mass spectrometer are: the ionization source is an electron bombardment type; the detector is a Faraday cup; the scanning range is 16 to 40; the acceleration voltage is 10 to 50 kV; the ion source temperature is 60 to 150° C.; and the electron energy is 70 to 110 eV.

[0012] Preferably, in the above-mentioned method for determining the abundance percentage of CO stable isotopes, the method for calculating the abundance percentage of CO stable isotopes according to the test results is: according to the relative intensity I of the mass numbers 28 and 29 obtained from the test results 28 and I 29 , the CO stable isotope abundance percentage is calculated by the formula.

[0013] Preferably, in the above-mentioned method for determining the percentage abundance of CO stable isotopes, the formula is CO stable isotope abundance percentage = I 29 / (I 28 +I 29 )×100%.

[0014] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention uses a gas isotope mass spectrometer to 13 CO and 12 CO in mixed gas 13 The key to the above detection method lies in the precise control of the vacuum degree of the pipeline before detection and the careful adjustment of the detection conditions during the detection process. In order to ensure the purity of the gas in the pipeline, the gas pressure in the pipeline is reduced to an extremely low level (1×10 -5 ~5×10 -5 Pa), thereby eliminating the potential impact of external impurities on the test results, thereby improving the detection accuracy of the gas isotope mass spectrometer. At the same time, the mass spectrometry parameters such as scanning range, acceleration voltage, ion source temperature and electron energy were optimized to further improve the accuracy of the detection effect and obtain specific detection results. 13 CO, 12 CO mixed gas detection method. The detection method of the present invention can realize 13 CO and 12 CO mixed gas 13 The accurate detection of C isotope abundance is not only highly sensitive, accurate and repeatable, but also simple, fast and low-cost. 12 CO and 13 This has laid a solid foundation for the optimization of CO isotope separation technology and provided strong support for related research in scientific research and industry. DETAILED DESCRIPTION

[0016] The present invention provides a method for determining the abundance percentage of stable isotopes of CO, comprising the following steps:

[0017] The detection parameters of the gas isotope mass spectrometer were set, the sampling pipeline of the gas isotope mass spectrometer was evacuated, and then the CO gas was introduced into the gas isotope mass spectrometer through the sampling pipeline for detection; the abundance percentage of the CO stable isotope was calculated according to the detection results.

[0018] In the present invention, the CO gas is preferably 12 CO and 13 CO mixed gas.

[0019] In the present invention, the vacuum degree of the vacuum pumping is preferably 1×10 -5 ~5×10 -5 Pa, more preferably 2×10 -5 ~4×10 -5 Pa, more preferably 3×10 -5 Pa.

[0020] In the present invention, the detection parameters of the gas isotope mass spectrometer are: the ionization source is preferably an electron bombardment type; the detector is preferably a Faraday cup; the scanning range is preferably 16 to 40; the acceleration voltage is preferably 10 to 50 kV, further preferably 20 to 50 kV, and more preferably 40 kV; the ion source temperature is preferably 60 to 150°C, further preferably 80 to 130°C, and more preferably 120°C; the electron energy is preferably 70 to 110 eV, further preferably 100 to 110 eV, and more preferably 110 eV.

[0021] In the present invention, the method for calculating the abundance percentage of stable isotopes of CO according to the test results is as follows: the relative intensity I of the mass numbers 28 and 29 obtained according to the test results is 28 and I 29 , the CO stable isotope abundance percentage is calculated by the formula.

[0022] In the present invention, the formula is:

[0023]

[0024] Where E is the abundance percentage of CO stable isotope.

[0025] In the present invention, the gas isotope mass spectrometer is a conventional commercially available gas isotope mass spectrometer in the art, and the present invention does not limit the model of the gas isotope mass spectrometer.

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for determining the abundance percentage of CO stable isotopes, comprising the following steps:

[0029] Set the detection parameters of the gas isotope mass spectrometer and evacuate the sampling line of the gas isotope mass spectrometer to a vacuum degree of 2×10 -5 Pa, then 12 CO and 13 The mixed gas of CO is introduced into the gas isotope mass spectrometer through the sampling pipeline for detection; the relative intensity I of the mass numbers 28 and 29 is obtained according to the detection results. 28 and I 29, 98.6% and 32.5% respectively. The stable isotope abundance percentage of CO calculated by the formula is 24.8%. After repeated detection, the relative intensity of mass numbers 28 and 29 is I 28 and I 29 The CO stable isotope abundance percentage is 25% calculated by the formula. The average value of the CO stable isotope abundance percentage detected twice is 24.9%.

[0030] Among them, the detection parameters of the gas isotope mass spectrometer are: the ionization source is electron bombardment type; the detector is a Faraday cup; the scanning range is 16 to 40; the acceleration voltage is 20 kV; the ion source temperature is 100°C; and the electron energy is 110 eV.

[0031] Example 2

[0032] This embodiment provides a method for determining the abundance percentage of CO stable isotopes, comprising the following steps:

[0033] Set the detection parameters of the gas isotope mass spectrometer and evacuate the inlet line of the gas isotope mass spectrometer to a vacuum degree of 1×10 -5 Pa, then 12 CO and 13 The mixed gas of CO is introduced into the gas isotope mass spectrometer through the sampling pipeline for detection; the relative intensity I of the mass numbers 28 and 29 is obtained according to the detection results. 28 and I 29 , respectively 95.2% and 27.3%. The stable isotope abundance percentage of CO calculated by the formula is 22.3%. After repeated detection, the relative intensity of mass numbers 28 and 29 is I 28 and I 29 The CO stable isotope abundance percentage is 22.1% calculated by the formula. The average value of the CO stable isotope abundance percentage of the two tests is 22.2%.

[0034] Among them, the detection parameters of the gas isotope mass spectrometer are: the ionization source is electron bombardment type; the detector is a Faraday cup; the scanning range is 16 to 40; the acceleration voltage is 40kV; the ion source temperature is 80°C; and the electron energy is 80eV.

[0035] Example 3

[0036] This embodiment provides a method for determining the abundance percentage of CO stable isotopes, comprising the following steps:

[0037] Set the detection parameters of the gas isotope mass spectrometer and evacuate the sample inlet line of the gas isotope mass spectrometer to a vacuum degree of 5×10 -5 Pa, then12 CO and 13 The mixed gas of CO is introduced into the gas isotope mass spectrometer through the sampling pipeline for detection; the relative intensity I of the mass numbers 28 and 29 is obtained according to the detection results. 28 and I 29 , 99.1% and 30.8% respectively. The stable isotope abundance percentage of CO calculated by the formula is 23.7%. After repeated detection, the relative intensity of mass numbers 28 and 29 is I 28 and I 29 The CO stable isotope abundance percentage is 24.1% calculated by the formula. The average value of the CO stable isotope abundance percentage of the two tests is 23.9%.

[0038] Among them, the detection parameters of the gas isotope mass spectrometer are: the ionization source is electron bombardment type; the detector is a Faraday cup; the scanning range is 16 to 40; the acceleration voltage is 30 kV; the ion source temperature is 120°C; and the electron energy is 100 eV.

[0039] Example 4

[0040] This embodiment provides a method for determining the abundance percentage of CO stable isotopes, comprising the following steps:

[0041] Set the detection parameters of the gas isotope mass spectrometer and evacuate the sample inlet line of the gas isotope mass spectrometer to a vacuum degree of 5×10 -5 Pa, then 12 CO and 13 The mixed gas of CO is introduced into the gas isotope mass spectrometer through the sampling pipeline for detection; the relative intensity I of the mass numbers 28 and 29 is obtained according to the detection results. 28 and I 29 , 96.7% and 36.9% respectively. The stable isotope abundance percentage of CO calculated by the formula is 27.6%. After repeated detection, the relative intensity of mass numbers 28 and 29 is I 28 and I 29 The CO stable isotope abundance percentage is 26.7% calculated by the formula. The average value of the CO stable isotope abundance percentage of the two tests is 27.2%.

[0042] Among them, the detection parameters of the gas isotope mass spectrometer are: the ionization source is electron bombardment type; the detector is a Faraday cup; the scanning range is 16 to 40; the acceleration voltage is 50 kV; the ion source temperature is 90°C; and the electron energy is 70 eV.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the abundance percentage of stable isotopes of CO, characterized in that: The following steps are involved: Setting the detection parameters of the gas isotope mass spectrometer, evacuating the sampling pipeline of the gas isotope mass spectrometer, and then introducing the CO gas into the gas isotope mass spectrometer through the sampling pipeline for detection; calculating the abundance percentage of the CO stable isotope according to the detection results; Wherein, the CO gas is 12 CO and 13 CO mixed gas.

2. The method for determining the abundance percentage of stable isotopes of CO according to claim 1, characterized in that: The vacuum degree of the vacuum pumping is 1×10 -5 ~5×10 -5 Pa.

3. The method for determining the abundance percentage of stable isotopes of CO according to claim 2, characterized in that: The detection parameters of the gas isotope mass spectrometer are: the ionization source is an electron bombardment type; the detector is a Faraday cup; the scanning range is 16-40; the acceleration voltage is 10-50 kV; the ion source temperature is 60-150° C.; and the electron energy is 70-110 eV.

4. The method for determining the abundance percentage of stable isotopes of CO according to claim 1 or 2, characterized in that: The method for calculating the abundance percentage of stable isotopes of CO according to the test results is as follows: the relative intensity I of the mass numbers 28 and 29 obtained from the test results is 28 and I 29 , the CO stable isotope abundance percentage is calculated by the formula.

5. The method for determining the abundance percentage of stable isotopes of CO according to claim 4, characterized in that: The formula is CO stable isotope abundance percentage = I 29 / (I 28 +I 29 )×100%.

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