Method for detecting total alpha and total beta radioactivity in a nasal swab sample

Abstract

The present application relates to a kind of total alpha and total beta radioactivity detection method in nasal cavity wiping sample, belong to the field of radioactivity measurement, by using thermoplastic polyurethane swab to carry out nasal cavity wiping sampling, using organic solvent as dissolving solution to dissolve the wiping head of thermoplastic polyurethane swab, add the scintillation solution suitable for alpha / beta discrimination measurement to dissolving solution, oscillation makes sample mix, alpha / beta discrimination measurement is carried out to the prepared sample.The total alpha and total beta radioactivity detection method in nasal cavity wiping sample disclosed in the present application can realize the rapid dissolution of wiping material in scintillation solution, effectively avoid the attenuation effect of wiping material on liquid scintillation measurement, improve the detection efficiency and measurement accuracy of alpha and beta radioactivity in nasal cavity wiping sample.

Description

Technical Field

[0001] The invention belongs to the field of radioactivity measurement, and in particular relates to a method for detecting total alpha and total beta radioactivity in a nasal swab sample. Background Art

[0002] Radioactive aerosols enter the human body through the respiratory system, and inhalation is one of the main pathways of internal radiation exposure. A report from the International Commission on Radiological Protection (ICRP) indicates that over 45% of aerosol particles with a median aerodynamic diameter of 5 μm in inhaled air are deposited in the anterior nasal passages. Therefore, detecting radioactivity in nasal swabs or mucus samples can effectively determine whether a person has been contaminated by airborne radioactivity.

[0003] Nasal swab testing has been widely used to monitor radioactive internal contamination of personnel in nuclear facilities during routine operation and accident situations. 239 Pu, 240 Pu, 241 Pu, 241 Am, 90 For difficult-to-detect α and β radionuclides such as Sr, the following methods have been reported: 1) The Japan Atomic Energy Agency's Nuclear Fuel Cycle Engineering Laboratory (JAEA-NFCEL) uses an air filter (40 mm diameter disc) wrapped around a conventional cotton swab tip for nasal swab sampling. After the filter is removed, measurements are made using a ZnS (Ag) scintillator detector; 2) Chengdu University of Technology uses conventional cotton swabs for nasal swab sampling, followed by measurements using a self-made α particle swab detector (mainly consisting of a cotton swab holder and a gold-silicon surface barrier detector); 3) Los Alamos National Laboratory (LANL) uses conventional cotton swabs for nasal swab sampling, removes the swab tip, immerses it in scintillation fluid, and measures it using a liquid scintillation spectrometer; 4) Atomic Energy of Canada's Chalk River Nuclear Laboratory (AECL-CRNL) uses polyurethane foam swabs for nasal swab sampling. After the swab tip is removed, it is immersed in scintillation fluid and measured using a liquid scintillation spectrometer for α / β discrimination.

[0004] Compared to solid-state detector measurements, liquid scintillation α / β discrimination measurements can achieve simultaneous determination of α and β radioactivity when applied to nasal swab sample analysis. They have high detection sensitivity for both α and β radioactivity, are easy to prepare, and can automatically change samples during measurement, offering significant technical advantages in nasal swab analysis applications. However, existing liquid scintillation analysis methods for nasal swab samples still have significant technical deficiencies. Whether using conventional cotton swabs or polyurethane foam swabs, the swab material attenuates α and β particles during liquid scintillation α / β discrimination measurements, reducing the detection efficiency and discrimination effectiveness of α and β particles. Summary of the Invention

[0005] In view of the defects in the prior art, the purpose of the present invention is to provide a method for detecting total α and total β radioactivity in nasal swab samples, which has the technical advantages of being quick, simple and with high measurement accuracy.

[0006] To achieve the above objectives, the present invention adopts a technical solution: a method for detecting total α and total β radioactivity in nasal swab samples, the method comprising the following steps:

[0007] S1. Nasal swab sampling using thermoplastic polyurethane swabs;

[0008] S2, dissolving the thermoplastic polyurethane swab using an organic solvent as a dissolving liquid;

[0009] S3. Add scintillation fluid suitable for α / β discrimination measurement to the dissolved solution and shake to mix the sample.

[0010] S4. Perform α / β discrimination measurement on the prepared samples.

[0011] Furthermore, in step S2, an organic solvent is used as a dissolving liquid to dissolve the wiping head of the thermoplastic polyurethane swab.

[0012] Furthermore, the wiping head of the thermoplastic polyurethane swab is thermoplastic polyurethane hot melt adhesive.

[0013] Furthermore, the organic solvent used as the dissolving liquid in step S2 is at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0014] Furthermore, in step S3, scintillation fluid is added so that the volume ratio of the dissolving liquid to the scintillation fluid is in the range of 0.1-1.

[0015] Furthermore, in step S4, a liquid scintillation spectrometer is used to perform α / β discrimination measurement on the prepared sample.

[0016] The beneficial technical effect of the present invention is that the method for detecting total α and total β radioactivity in nasal swab samples disclosed by the present invention provides a simple, fast and reliable method for detecting total α and total β radioactivity in nasal swab samples in response to the needs of detecting α and β radioactive aerosol contamination in personnel. Nasal swab sampling is performed using a thermoplastic polyurethane swab, the swab head material is dissolved using an organic solution, and the α / β discrimination measurement of the liquid scintillator is performed after mixing with the scintillation liquid. The swab material can be completely dissolved in the scintillation liquid, effectively avoiding the attenuation effect of the swab material on α and β particles. Compared with the existing nasal swab sample detection technology, the detection efficiency of α and β nuclides in nasal swab samples is significantly improved and the interference of the swab material on radioactivity measurement is eliminated. In addition, after adjusting the shape of the swab sampling swab, the method is suitable for the detection of α and β radioactive surface contamination in the environment and workplace. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of a method for detecting total α and total β radioactivity in a nasal swab sample according to Example 1 of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1

[0020] like Figure 1 As shown, an embodiment of the present invention provides a method for detecting total α and total β radioactivity in a nasal swab sample, the method comprising the following steps:

[0021] S1. Nasal swab sampling using thermoplastic polyurethane swabs;

[0022] S2, using an organic solvent as a dissolving liquid to dissolve the wiping head of the thermoplastic polyurethane swab;

[0023] The wiping head material is thermoplastic polyurethane hot melt adhesive, and the organic solvent is selected from at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0024] S3. Add scintillation fluid suitable for α / β discrimination measurement to the dissolved solution and shake to mix the sample.

[0025] The volume ratio of the dissolving solution to the scintillation fluid ranges from 0.1 to 1.

[0026] S4. Use a liquid scintillation analyzer to perform α / β discrimination measurement on the prepared samples.

[0027] Example 2

[0028] The detection efficiency of α and β radioactivity using a liquid scintillation spectrometer was determined using the method for detecting total α and β radioactivity in nasal swab samples provided in Example 1 of the present invention. The method comprises: taking two nasal sampling swabs, adding pure α and pure β radioactive substances to the swab tips, respectively; performing radioactivity measurements according to the method for detecting total α and β radioactivity in nasal swab samples provided in Example 1 of the present invention; and calculating the detection efficiency of α and β radioactivity using a liquid scintillation spectrometer based on the measurement results. The detailed steps are as follows:

[0029] 1) Preparation of α-radioactive spiked samples: Take a thermoplastic polyurethane swab and add 0.1 mL of 210 Po solution, the solution matrix is ​​1mol / L HNO3, 210 The Po activity is 5.8 Bq. The wipe head is then placed in a 20 mL standard liquid scintillation bottle and the sample is recorded as sample 1.

[0030] 2) Preparation of β-radioactive spiked samples: Take a thermoplastic polyurethane swab and add 0.1 mL of90 Sr solution, the solution matrix is ​​1 mol / L HNO3, where 90 Sr and 90 Y is in long-term radioactive equilibrium, 90 The Sr activity is 21.3 Bq. The wipe head is then placed in a 20 mL standard liquid scintillation bottle and the sample is recorded as sample 2.

[0031] 3) Blank sample: Take a thermoplastic polyurethane swab and add 0.1 mL of 1 mol / L HNO3 solution to the swab tip. Then, place the swab tip in a 20 mL standard liquid scintillation vial. This sample is recorded as Sample 3.

[0032] 4) Add 3 mL of N,N-dimethylformamide to each of samples 1, 2, and 3 and shake for 30 seconds to dissolve the wiper.

[0033] 5) Add 10 mL of commercially available scintillation fluid suitable for α / β discrimination measurement to each of Samples 1, 2, and 3, and shake for 10 seconds to mix the solution and scintillation fluid.

[0034] 6) Measure the sample for 600 s using a liquid scintillation meter equipped with an α / β discrimination measurement module.

[0035] 7) According to the counting rate of sample 1 and sample 3 in the α signal area, the liquid scintillation meter is 210 The detection efficiency of Po is 98.2%. According to the counting rate of sample 2 and sample 3 in the β signal area, the liquid scintillator has a good detection efficiency of 98.2%. 90 Sr / 90 The detection efficiency of Y is 97.6%.

[0036] Example 3

[0037] The accuracy of the method for detecting total α and total β radioactivity in nasal swab samples provided in Example 1 of the present invention was verified by quantitatively adding α and β radioactive substances to the nasal sampling swab as a spiked sample with known radioactivity, measuring the total α and total β radioactivity in the nasal swab sample according to the method for detecting total α and total β radioactivity in the nasal swab sample provided in Example 1 of the present invention, and verifying whether the measured values ​​were consistent with the theoretical values. The detailed steps are as follows:

[0038] 1) Preparation of spiked samples: Take a thermoplastic polyurethane swab and add 0.05 mL of 210 Po solution (solution matrix is ​​1 mol / L HNO3 solution, 210 Po activity is 3.2Bq) and 0.05mL 90 Sr solution (solution matrix is ​​1 mol / L HNO3, where 90 Sr and 90 Y is in long-term radioactive equilibrium, 90The swab head was then placed in a 20 mL standard liquid scintillation vial and recorded as Sample 4.

[0039] 2) Blank sample: Take a thermoplastic polyurethane swab and add 0.1 mL of 1 mol / L HNO3 solution to the swab tip. Then, place the swab tip in a 20 mL standard liquid scintillation vial. This sample is recorded as Sample 5.

[0040] 3) Add 3 mL of N,N-dimethylformamide to each of samples 4 and 5 and shake for 30 seconds to dissolve the wiper.

[0041] 4) Add 10 mL of commercially available scintillation fluid suitable for α / β discrimination measurement to each of samples 4 and 5, and shake for 10 seconds to mix the solution and scintillation fluid.

[0042] 5) Measure the sample for 600 s using a liquid scintillation meter equipped with an α / β discrimination measurement module.

[0043] 6) According to the counting rate of samples 4 and 5 in the α signal area and the counting rate of samples 5 in the α signal area, the 210 The detection efficiency of Po can be calculated to obtain the 210 The Po activity is 3.4Bq.

[0044] According to the counting rates of samples 4 and 5 in the β signal region and the 90 Sr / 90 The detection efficiency of Y can be calculated to obtain 90 Sr+ 90 The Y activity is 20.9 Bq. It can be seen that the radioactivity measurement is performed using the total α and total β radioactivity detection method in the nasal swab sample provided in Example 1 of the present invention. The test measurement value is consistent with the theoretical value, and the measurement accuracy is high.

[0045] As can be seen from the above examples, the present invention discloses a method for detecting total α and total β radioactivity in nasal swab samples. The method comprises using a thermoplastic polyurethane swab for nasal swab sampling, dissolving the swab head of the thermoplastic polyurethane swab using an organic solvent as a dissolving liquid, adding a scintillation fluid suitable for α / β discrimination measurement to the dissolving liquid, oscillating the sample to mix it, and performing α / β discrimination measurement on the prepared sample. The method disclosed in the present invention for detecting total α and total β radioactivity in nasal swab samples can achieve rapid dissolution of the swab material in the scintillation fluid, effectively preventing the attenuation effect of the swab material on the liquid scintillation measurement, and improving the detection efficiency and measurement accuracy of α and β radioactivity in nasal swab samples.

[0046] The method described in the present invention is not limited to the embodiments described in the specific implementation manner. Those skilled in the art may derive other implementation manners based on the technical solution of the present invention, which also fall within the scope of the technical innovation of the present invention.

Claims

1. A method for detecting total alpha and total beta radioactivity in a nasal swab sample, the method comprising the following steps: S1. Nasal swab sampling using thermoplastic polyurethane swabs; S2, dissolving the thermoplastic polyurethane swab using an organic solvent as a dissolving liquid; S3. Add scintillation fluid suitable for α / β discrimination measurement to the dissolved solution and shake to mix the sample. S4. performing α / β discrimination measurement on the prepared samples; In step S2, an organic solvent is used as a dissolving liquid to dissolve the wiping head of the thermoplastic polyurethane swab, which can achieve rapid dissolution of the wiping material in the scintillation liquid and effectively avoid the attenuation effect of the wiping material on the liquid scintillation measurement; The wiping head of the thermoplastic polyurethane swab is thermoplastic polyurethane hot melt adhesive.

2. A method for detecting total α and total β radioactivity in a nasal swab sample according to claim 1, characterized in that: The organic solvent used as the dissolving liquid in step S2 is at least one of N,N-dimethylformamide and dimethyl sulfoxide.

3. A method for detecting total α and total β radioactivity in a nasal swab sample according to claim 1, characterized in that: In step S3, scintillation fluid is added so that the volume ratio of the dissolving liquid to the scintillation fluid is in the range of 0.1-1.

4. A method for detecting total α and total β radioactivity in a nasal swab sample according to claim 1, characterized in that: In step S4, a liquid scintillation spectrometer is used to perform α / β discrimination measurement on the prepared sample.

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