A method for detecting radioactive substances in food

Abstract

The present application relates to a kind of detection methods of radioactive material in food, comprising the steps of: obtaining food sample, by microwave digestion the food sample is rapidly ashed;Prepare detection microparticle, the detection microparticle can produce property change when contacting with radioactive material;The detection microparticle is mixed with the food sample after ashing;Separate the detection microparticle, detect the change signal of the detection microparticle;Output the radioactive detection result of the food sample.This method can quickly detect a large number of food samples by microwave digestion and detection microparticle method, the whole detection process is relatively simple, only a few steps are needed to complete detection, without complex operation and equipment, can provide rapid detection results, can quickly evaluate the safety of food in nuclear radiation emergency or in the scene that needs rapid detection such as airport / customs, etc.;In addition, this detection method does not need large equipment and complex laboratory conditions, can carry out rapid detection in the place that needs, can effectively help to realize the demand of food safety monitoring and radiation event emergency disposal.

Description

Technical Field

[0001] This invention relates to the field of food testing technology, and in particular to a method for detecting radioactive substances in food. Background Technology

[0002] Any nuclear and radiation emergency may release radioactive materials into the environment, polluting the air, food, drinking water, and human body surfaces, and then entering the human body through various routes to cause internal radiation exposure.

[0003] Taking the radioactive substance strontium-90 as an example, the determination of radioactive strontium-90 in food can currently be based on GB14883.3—2016 "National Food Safety Standard—Determination of Radioactive Substances Strontium-89 and Strontium-90 in Food" or HJ815-2016 "Radiochemical Analysis Method for Strontium-90 in Ash of Water and Biological Samples". There are three methods for determining strontium-90 in the standards: Method 1 is the di-(2-ethylhexyl)phosphoric acid extraction method (i.e., liquid-liquid extraction method); Method 2 is the ion exchange method (i.e., solid-phase extraction method); and Method 3 is the fuming nitric acid method.

[0004] However, regardless of which method is used, there are problems such as complicated experimental procedures and long time consumption. They cannot achieve efficient detection in response to nuclear and radiation emergencies, which is not conducive to carrying out timely intervention actions.

[0005] Therefore, how to quickly detect radioactive substances in food has become a pressing technical problem that needs to be solved. Summary of the Invention

[0006] This invention discloses a method for detecting radioactive substances in food, aiming to solve the technical problems existing in the prior art. The invention adopts the following technical solution:

[0007] This invention provides a method for detecting radioactive substances in food, comprising the following steps:

[0008] Obtain food samples and rapidly ashed them using microwave digestion;

[0009] Prepare detector particles that can undergo property changes when in contact with radioactive materials;

[0010] The detection particles were thoroughly mixed with the ashed food sample;

[0011] Separate the detection particles and detect the changing signals of the detection particles;

[0012] Output the radioactivity test results of food samples.

[0013] As a preferred technical solution, the step of rapidly ashing food samples via microwave digestion further includes:

[0014] Weigh the food sample to be digested and place it in the digestion container;

[0015] Add a digesting agent to the food sample;

[0016] Place the digestion container containing the food sample and digesting agent into the microwave digestion equipment and start the equipment to perform microwave digestion;

[0017] After microwave digestion is complete, remove the digestion container and cool it to obtain the ashed food sample.

[0018] As a preferred technical solution, the food sample is a solid food, a semi-solid food, or a liquid food.

[0019] As a preferred technical solution, the digesting agent includes nitric acid or hydrofluoric acid.

[0020] As a preferred technical solution, the step of preparing the detector particles further includes:

[0021] Preparation of magnetic nanoparticles;

[0022] The surface of magnetic nanoparticles is modified, including coating the surface of magnetic nanoparticles with a modifying material, which includes a material that can produce a property change when in contact with radioactive substances.

[0023] The detected particles were obtained.

[0024] As a preferred technical solution, the step of preparing magnetic nanoparticles further includes:

[0025] The target iron salt is dissolved in a solvent to obtain an iron ion solution;

[0026] By adding reducing agents and surfactants, precursors for magnetic nanoparticles are generated, and the size and dispersibility of the precursors are controlled.

[0027] Adjusting the temperature and pH value allows magnetic nanoparticles to gradually form;

[0028] Magnetic nanoparticles were obtained by screening, washing, and drying.

[0029] As a preferred technical solution, the target iron salt is selected from one or more of ferric chloride, ferrous chloride, ferric sulfate, and ferrous sulfate.

[0030] As a preferred technical solution, the step of modifying the surface of magnetic nanoparticles further includes:

[0031] Magnetic nanoparticles and silicon source are added to water or organic solvent and mixed to form a homogeneous sol.

[0032] Add the modified material to the sol and ensure uniform dispersion;

[0033] Add an appropriate amount of silane coupling agent to the sol to cause the modified material to undergo a coupling reaction with the silicon source;

[0034] At the target rotation speed, a modified material is deposited on the surface of magnetic nanoparticles using a sol-gel method to obtain surface-modified magnetic microspheres.

[0035] As a preferred technical solution, the modified material includes scintillator material, semiconductor material or nuclear magnetic resonance material.

[0036] As a preferred technical solution, the step of detecting the change signal of the probe particles also specifically includes:

[0037] The intensity and wavelength of emitted light are measured using a spectrometer;

[0038] Alternatively, changes in energy level structure can be detected using electron spectroscopy.

[0039] Alternatively, nuclear magnetic resonance imaging (NMR) can be used to monitor changes in nuclear spin state.

[0040] Compared with the prior art, one embodiment of the above invention has the following advantages or beneficial effects:

[0041] This invention provides a method for detecting radioactive substances in food. This method utilizes microwave digestion and particle detection to rapidly test large quantities of food samples. The entire testing process is relatively simple, requiring only a few steps and eliminating the need for complex operations and equipment. It provides rapid results, enabling quick assessment of food safety in scenarios requiring rapid detection, such as nuclear radiation emergencies or at airports / customs. Furthermore, this method does not require large equipment or complex laboratory conditions, allowing for rapid testing wherever needed, effectively supporting food safety monitoring and emergency response to radiation incidents. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0043] Figure 1 This is a flowchart of a preferred embodiment of the method for detecting radioactive substances in food disclosed in this invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0045] In the description of this invention, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] Traditional methods for detecting radioactive substances in food require sample pretreatment, laboratory analysis, and data processing. These processes are time-consuming, require large equipment or complex laboratory conditions, and require experienced operators, making them unsuitable for rapid detection in emergency situations.

[0048] To solve the above problems, refer to Figure 1 This embodiment discloses a method for detecting radioactive substances in food, aiming to shorten the detection process and meet the needs of rapid detection in special scenarios. The detection method includes steps S110 to S150, as follows:

[0049] Step S110: Obtain a food sample and rapidly ashing the food sample using microwave digestion.

[0050] In a preferred embodiment, the food sample may be a solid food, a semi-solid food, or a liquid food.

[0051] During microwave digestion, food samples can be heated rapidly and uniformly by microwave heating, which promotes the combustion and transformation of organic matter in the sample, thereby achieving rapid ashing. Compared with traditional heating methods, microwave digestion can significantly shorten the ashing time and improve ashing efficiency while maintaining the integrity of the sample.

[0052] In a preferred embodiment, the specific steps of microwave digestion include steps S111 to S114.

[0053] Step S111: Weigh the food sample to be digested and place it in the digestion container.

[0054] Preferably, the weight of the food sample directly affects the amount of digester used and the setting of reaction conditions during the digestion process. By weighing the food sample, the ratio of digester to sample can be accurately controlled, ensuring the accuracy and stability of reaction conditions during digestion. Secondly, weighing the food sample can serve as an important basis for recording experimental data, which is beneficial for subsequent data traceability and result verification. It also facilitates quality control by experimental personnel, avoids sample errors and experimental deviations, and improves the reliability and repeatability of the experiment.

[0055] Preferably, when selecting a digestion container, glass, ceramic, or special plastic can be used. The specific choice should be made according to the characteristics of the food sample, and no specific limitation is made in this embodiment.

[0056] Step S112: Add digesting agent to food sample.

[0057] Alternatively, nitric acid or hydrofluoric acid can be used as the digesting agent.

[0058] Step S113: Place the digestion container containing the food sample and digesting agent into the microwave digestion equipment and start the equipment to perform microwave digestion.

[0059] Preferably, the microwave digestion equipment is a microwave digester. After the digestion container is placed in the microwave digester, a comprehensive judgment is made based on the composition of the food sample, the composition of the digesting agent, and the material of the digestion container, and corresponding digestion parameters are set to ensure the efficiency of the digestion process, the accuracy of the digestion results, and the reliability of the data.

[0060] Preferably, based on different food sample types and digesting agents, preliminary experiments can be conducted to determine the optimal microwave power and time range, and then adjustments can be made according to the actual situation. Since different food samples have different microwave digestion temperatures and times, no specific limitations are made in this embodiment.

[0061] Step S114: After microwave digestion is complete, remove the digestion container and cool it to obtain the ashed food sample.

[0062] Preferably, after microwave digestion, the food sample is burned to become ash. More preferably, in this embodiment, since the subsequent detection of the ashed food sample based on the detection particles does not require acidity, no additional acid removal operation is needed, further shortening the entire detection process and operation time.

[0063] Step S120: Prepare detector particles that can undergo property changes when in contact with radioactive materials.

[0064] In existing technologies, ashing food samples need to be prepared into solutions first, and then radionuclides are detected by a low-background β meter. The process is cumbersome and the analysis of the detection results is complex, making it unsuitable for rapid detection. Therefore, in this embodiment, special detection particles need to be prepared in advance. When performing detection, the pre-prepared detection particles are used directly, without the need for on-site preparation.

[0065] In a preferred embodiment, the preparation step of the detection particles includes steps S121 to S123.

[0066] Step S121: Prepare magnetic nanoparticles.

[0067] First, the target iron salt is dissolved in a solvent to obtain an iron ion solution; optionally, the target iron salt is selected from one or more of ferric chloride, ferrous chloride, ferric sulfate and ferrous sulfate.

[0068] Then, a reducing agent is added to reduce the iron ions and generate a precursor for magnetic nanoparticles. At the same time, a surfactant is added to control the size and dispersibility of the precursor and to help stabilize the formation of nanoparticles.

[0069] Secondly, by adjusting the temperature and pH value, magnetic nanoparticles are gradually formed.

[0070] Finally, the resulting mixture is screened by centrifugation or other separation techniques, and the remaining impurities are washed with solvent; the washed nanoparticles are dried under appropriate conditions to obtain magnetic nanoparticles.

[0071] Step S122 involves modifying the surface of the magnetic nanoparticles. The modification includes coating the surface of the magnetic nanoparticles with a variable material, which includes a material that can produce a property change when in contact with radioactive substances.

[0072] In step S121 above, magnetic nanoparticles are first prepared to ensure that the detection particles can be sorted in one go based on magnetism when sorting the detection particles from the ashed food sample. In this step, by modifying the surface of the magnetic nanoparticles with a different material, the detection particles can undergo specific physical or chemical changes after being excited by nuclear radiation. By detecting these changes, the radionuclides in the food sample can be indirectly qualitatively or quantitatively detected. Furthermore, the detected signals are converted into meaningful data and the results are output to indicate the presence and content of radionuclides in the food sample.

[0073] When modifying the surface of magnetic nanoparticles, a certain amount of magnetic nanoparticles and silicon source (silicone ester) are first added to an aqueous solution or organic solvent and mixed to form a homogeneous solution. Then, the modifier is added to the sol and uniformly dispersed. The modifier can be a scintillator material, a semiconductor material, or a nuclear magnetic resonance (NMR) material. Scintillator materials can include cesium iodide (CsI), sodium cesium iodide (NaI(Tl)), or lead molybdate (PbMoO4), etc. These materials produce light scintillation upon exposure to nuclear radiation, and the radiation dose received by the sample can be determined based on the intensity and frequency of the scintillation. Semiconductor materials can be silicon (Si) or germanium (Ge), which exhibit changes in electronic energy level structure after exposure to nuclear radiation. The level of nuclear radiation can be determined by detecting the number of free electrons released. NMR materials can include iron oxide (Fe2O3), copper oxide (CuO), erbium oxide (Er2O3), etc. These materials produce specific NMR signals after exposure to nuclear radiation, which can be used for nuclear radiation detection.

[0074] Next, an appropriate amount of silane coupling agent (such as trimethoxysilane) is added to the sol to cause the modified material to undergo a coupling reaction with the silicon source. Finally, at a target rotation speed (such as 2000-18000 rpm), the modified material is deposited on the surface of the magnetic nanoparticles by the sol-gel method to obtain surface-modified magnetic microspheres.

[0075] Step S123: Dry the magnetic microspheres from step S122 to obtain the detection particles.

[0076] Step S130: Thoroughly mix the probe particles with the ashing food sample.

[0077] In a preferred embodiment, the detection particles can be directly mixed with the ashed food sample in a dry state, and the uniformity of the mixture can be ensured by ultrasonic vibration.

[0078] In another preferred embodiment, the detector particles can be suspended in a suitable solvent and fully dispersed by ultrasonic treatment or stirring. Then, the ashing food sample is added to the solution containing the detector particles, and the solution is then properly mixed. The detector particles and the food sample can be fully mixed by gentle stirring or shaking.

[0079] Step S140: Separate the probe particles and detect the change signals of the probe particles.

[0080] Preferably, since the detector particles are magnetic, they can be quickly separated by applying an external magnetic field. Especially in solution, after applying a magnetic field outside the container, the detector particles will be subjected to magnetic force and quickly settle or gather at the bottom or side of the container, thereby achieving the separation effect. Then, the supernatant can be carefully poured out or extracted to separate the magnetic microspheres. If further purification or treatment of the separated magnetic microspheres is required, a washing step can be performed.

[0081] Optionally, when modifying the surface of the magnetic microspheres, the surface can be modified with scintillator materials, semiconductor materials, or nuclear magnetic resonance materials, respectively. When modified with scintillator materials, the intensity and wavelength of emitted light are measured by a spectrometer to quantitatively or qualitatively detect nuclear radiation; when modified with semiconductor materials, changes in energy level structure are detected by electron spectroscopy to quantitatively or qualitatively detect nuclear radiation; when modified with nuclear magnetic resonance materials, changes in nuclear spin state are monitored by a nuclear magnetic resonance spectrometer to quantitatively or qualitatively detect nuclear radiation.

[0082] In a preferred embodiment, when the surface of the probe particle is a scintillator material, the detection method is as follows:

[0083] The spectrometer is set to fluorescence or emission mode. The detector particles are then placed in the spectrometer to excite them to emit light signals. The intensity and wavelength of the emitted light signals generated by the scintillator material on the surface of the detector particles are observed and recorded. The emission spectral data recorded by the spectrometer are used to analyze and process the spectral peaks, including the extraction and measurement of parameters such as peak intensity and peak position. Then, by comparing the spectral data of the detector particles with standard curves or reference data, nuclear radiation can be detected quantitatively or qualitatively.

[0084] In a preferred embodiment, when the surface of the probe particle is a semiconductor material, the detection method is as follows:

[0085] By placing the probe particles in an XPS instrument and using X-rays to excite the surface of the probe particles, causing them to emit electrons, the changes in the electronic energy level layout and chemical bond states of the semiconductor material on the surface of the probe particles can be observed by analyzing the energy level structure data obtained from XPS. Based on the changes in the characteristic peaks of the probe particles in the XPS spectrum and the adjustment of the energy level structure, the effects of nuclear radiation can be quantitatively or qualitatively detected. Then, by comparing the XPS spectral data of the probe particles with standard curves or reference data, nuclear radiation can be quantitatively or qualitatively detected.

[0086] In a preferred embodiment, when the surface of the probe particle is a nuclear magnetic resonance material, the detection method is as follows:

[0087] By placing the probe particles in a nuclear magnetic resonance (NMR) spectrometer and adjusting the magnetic field and radio frequency pulse parameters to excite the nuclear spins on the surface of the probe particles, the generated NMR signals, including peak shape, intensity, and frequency, can be observed and recorded. Based on the changing characteristics of the nuclear spin signals in the NMR spectrum, the effects of nuclear radiation can be quantitatively or qualitatively detected. By comparing the NMR spectrum data of the probe particles with standard curves or reference data, changes caused by nuclear radiation can be assessed and detected.

[0088] Step S150: Output the radioactivity detection results of the food sample.

[0089] Based on the detection results of the change signal in step S140 above, qualitative or quantitative detection results can be output according to requirements.

[0090] Specifically, when rapid detection is required, qualitative detection can be selected. When the signal change of the detected particles exceeds the preset threshold, it can be determined that there are radioactive nuclides in the food sample, or that it has been contaminated by radioactive nuclides. When more accurate detection results are required, quantitative detection can be selected. By comparing the difference between the signal curve of the detected particles and the standard curve, the content of radioactive nuclides in the food sample can be indirectly determined.

[0091] Compared with existing technologies, the detection method provided in this embodiment can quickly detect a large number of food samples by microwave digestion and particle detection. The entire detection process is relatively simple, requiring only a few steps to complete the detection. It does not require complex operations or equipment and can provide rapid detection results. It can quickly assess the safety of food in scenarios requiring rapid detection, such as nuclear radiation emergencies or airports / customs. In addition, this detection method does not require large equipment or complex laboratory conditions, and can be carried out rapidly wherever needed, effectively helping to meet the needs of food safety monitoring and emergency response to radiation incidents.

[0092] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0093] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0094] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0095] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose.

Claims

1. A method for detecting radioactive substances in food, characterized in that, Including the following steps: Obtain food samples and rapidly ashing the food samples using microwave digestion; Prepare detector microparticles, the detector microparticles being magnetic, and their surfaces being modified with a changing material, the changing material including scintillator materials, semiconductor materials, or nuclear magnetic resonance materials, the changing material being able to undergo a property change upon contact with radioactive materials; The detection particles are thoroughly mixed with the ashed food sample; The detection particles are separated by applying an external magnetic field, and the change signals of the detection particles are detected. Output the radioactivity test results of the food sample.

2. The method for detecting radioactive substances in food according to claim 1, characterized in that, The step of rapidly ashing the food sample via microwave digestion further includes: Weigh the food sample to be digested and place it in the digestion container; Add a digesting agent to the food sample; Place the digestion container containing the food sample and the digesting agent into the microwave digestion equipment and start the equipment to perform microwave digestion; After microwave digestion is complete, the digestion container is removed and cooled to obtain the ashed food sample.

3. The method for detecting radioactive substances in food according to claim 2, characterized in that, The food samples are solid food, semi-solid food, or liquid food.

4. The method for detecting radioactive substances in food according to claim 2, characterized in that, The digesting agent includes nitric acid or hydrofluoric acid.

5. The method for detecting radioactive substances in food according to claim 1, characterized in that, The step of preparing the detector particles further includes: Preparation of magnetic nanoparticles; The surface of the magnetic nanoparticles is modified, the modification including coating the surface of the magnetic nanoparticles with a variable material, the variable material including a material that can produce a property change when in contact with radioactive substances; The probe particles were obtained.

6. The method for detecting radioactive substances in food according to claim 5, characterized in that, The step of preparing magnetic nanoparticles further includes: The target iron salt is dissolved in a solvent to obtain an iron ion solution; A reducing agent and a surfactant are added to generate a precursor for the magnetic nanoparticles, and the size and dispersibility of the precursor are controlled. Adjusting the temperature and pH value allows the magnetic nanoparticles to gradually form; The magnetic nanoparticles were obtained by screening, washing, and drying.

7. The method for detecting radioactive substances in food according to claim 6, characterized in that, The target iron salt is selected from one or more of ferric chloride, ferrous chloride, ferric sulfate, and ferrous sulfate.

8. The method for detecting radioactive substances in food according to claim 6, characterized in that, The step of modifying the surface of the magnetic nanoparticles further includes: The magnetic nanoparticles and silicon source are added to water or an organic solvent and mixed to form a homogeneous sol. The modified material is added to the sol, ensuring uniform dispersion; Add an appropriate amount of silane coupling agent to the sol to cause the modified material to undergo a coupling reaction with the silicon source; At the target rotational speed, the modified material is deposited on the surface of the magnetic nanoparticles using a sol-gel method to obtain surface-modified magnetic microspheres.

9. The method for detecting radioactive substances in food according to claim 1, characterized in that, The step of detecting the change signal of the probe particles further includes: The intensity and wavelength of emitted light are measured using a spectrometer; Alternatively, changes in energy level structure can be detected using electron spectroscopy. Alternatively, nuclear magnetic resonance imaging (NMR) can be used to monitor changes in nuclear spin state.

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