Water-based wide temperature range scintillation liquid complex system, and radioactive detection method and sensor thereof

Abstract

The application discloses a water-based wide-temperature-range scintillation liquid compounding system, a radioactive detection method and a sensor, and the system is composed of a scintillator, nonionic, anionic and zwitterionic surfactants, a cosolvent, a solvent and water; by regulating the polymerization chain length of the nonionic surfactant, the HLB value is accurately controlled, the surface tension is optimized, and the efficient connection of the scintillation phase and the radionuclide water phase is realized; the anionic surfactant reduces the interfacial tension, and ensures the uniform dispersion of components; the zwitterionic surfactant dynamically adjusts the HLB value through the dissociation degree of the charge group, and the dissociation degree of the charge group can change with temperature, and the micelle structure stability is dynamically adjusted in a wide temperature range. The scintillation liquid has excellent detection efficiency and extremely low detection limit, and has outstanding water containing performance and temperature adaptability, and brings more efficient and accurate technical support to the field of radioactivity detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radionuclide detection materials and sensor technology, and particularly relates to a water-based wide-temperature-range scintillation liquid compounding system, a radionuclide detection method and a sensor. BACKGROUND

[0002] As a core material in the fields of nuclear radiation detection, particle physics experiments, environmental monitoring and medical imaging, scintillation liquid realizes the detection and analysis of radiation sources by converting the energy of radioactive particles into visible light signals. The global annual demand exceeds 5 million liters, and the market size exceeds 1 billion US dollars. However, the current high-performance scintillation liquid market mainly relies on imports, and there are problems such as long import cycle and high price (such as PerkinElmer's Ultima Gold LLT series). Under the influence of complex international situation and trade policy, it brings pressure and uncertainty to the development of domestic related industries.

[0003] Although the existing scintillation liquid technology has achieved certain breakthroughs in the field of radioactive detection, and the light output stability of some products in specific scenarios has reached the industry standard, there are still two significant bottlenecks when facing actual application scenarios: first, the current mainstream scintillation liquid generally has limited compatibility with water, and the water holding capacity is less than 40%. This means that when facing natural high-water-content samples such as blood, body fluids, and high-humidity soil, complicated dehydration or extraction treatment is required, which not only increases the detection cost but also may cause loss of radioactive substances due to the pretreatment process. Second, the stability of the current mainstream scintillation liquid in the conventional laboratory temperature range of <15℃ and >30℃ is poor. For example, in the summer high-temperature environment in the south, the surfactant micelles may collapse due to high-temperature dehydration, resulting in turbidity of the solution and a sharp drop in fluorescence efficiency. In the winter low-temperature environment in the north, the micelle structure may lose solubilizing ability due to low-temperature contraction, and the water phase is precipitated in the form of ice crystals, directly affecting the accuracy of the detection results. This "fear of heat in the south and fear of cold in the north" characteristic makes it difficult for the same batch of scintillation liquid to be used nationwide, especially in outdoor operations and cross-regional emergency monitoring scenarios, which requires separate customization of the formula for different regions, significantly increasing the technical application threshold.

[0004] Therefore, in view of the above problems, the present application provides a water-based wide-temperature-range scintillation liquid compounding system, a radionuclide detection method and a sensor, a high-performance scintillation liquid compounding system with wide-temperature-range adaptability, high water holding capacity and low detection limit, which effectively breaks through the multiple bottlenecks of existing technology in water compatibility, temperature range stability and detection sensitivity. SUMMARY

[0005] The purpose of this invention is to address the multiple core defects of existing scintillation fluids, including insufficient aqueous phase compatibility, limited temperature range stability, insufficient detection sensitivity, and significant quenching effect of the scintillator itself. This invention provides a water-based, wide-temperature-range scintillation fluid composite system, along with its radioactivity detection method and sensor. This composite system can be directly coupled with a radioactivity detection sensor. The homogeneous dispersion formed by the system can closely contact the sensor's detection end, reducing optical signal loss and enabling the sensor to more efficiently capture the scintillation light converted from radiation energy. The scintillation fluid provided by this invention not only increases the aqueous phase volume capacity to 70%, nearly 80% higher than current mainstream scintillation fluid products (such as Ultima Gold LLT), achieving homogeneous stability across the entire temperature range of 10℃ to 40℃; but also utilizes micellar solubilization and wavelength transfer technology to... 3 H detection limit as low as 3.66×10 -3 Bq / mL, effectively overcoming multiple bottlenecks in existing technologies in terms of aqueous phase compatibility, temperature range stability and detection sensitivity, combining technological innovation with supply chain autonomy.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for detecting radioactivity in a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants includes the following steps:

[0008] S1. Sample preparation: Take a water sample or a high-aqueous phase sample containing the target radionuclide. No dehydration or organic phase extraction is required.

[0009] S2. Scintillation fluid mixing: The sample of the target radionuclide is mixed with a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants at a volume ratio of 1:1, and stirred at a speed of 200-300 r / min for 10-30 seconds to form a uniform, clear and stable dispersion system.

[0010] S3. Setting detection conditions: Transfer the uniformly dispersed system obtained in step S2 into a liquid scintillation counter bottle and place it in a liquid scintillation counter with an integrated radioactivity detection sensor (the radioactivity detection sensor is a photoelectric sensing component adapted to scintillation light signals, used to capture visible light signals emitted by the scintillator); set the detection temperature to 10℃~40℃, the photomultiplier tube voltage to 800~1200V, and the counting time to 1~10 minutes.

[0011] S4. Signal Acquisition and Analysis: The scintillation light signal is acquired by the radioactivity detection sensor in the liquid scintillation counter. After the sensor converts the light signal into an electrical signal, it is processed by a multi-channel pulse analyzer, and finally the activity concentration of the target radionuclide is calculated.

[0012] The water-based wide-temperature-range scintillation fluid compound system, comprising multiple surfactants with synergistic effects, includes the following components by mass percentage:

[0013] The composition includes 1-5% scintillator, 20-45% nonionic surfactant, 2-10% anionic surfactant, 0.2-2% amphoteric surfactant, 3-20% cosolvent, 30-50% solvent, and 0.5-3% water.

[0014] The scintillator comprises a first scintillator and a second scintillator. The first scintillator is selected from one or more of 2,5-diphenyloxazole (PPO), 2-phenyloxazole (PO), 2,5-di(4-methylphenyl)oxazole (MPPO), terphenyl (TP), and 2-phenyl-5-(4-diphenyl)-1,3,4-oxazole (PBD). The second scintillator is selected from one or more of 1,4-bis(2-methylstyryl)benzene (bis-MSB), 1,4-bis[2-(5-phenyl)oxazolyl]benzene (POPOP), 1,4-bis[2-(4-methyl-5-phenyloxazolyl)]benzene (DMPOPOP), and 2-(4'-diphenyl)-6-phenylbenzoxazole (PBBO). The second scintillator accounts for 5% to 20% of the total scintillator, more preferably 1% to 2.5%.

[0015] More preferably, the content of the scintillator is 1-2.5%.

[0016] Preferably, the mass ratio of the zwitterionic surfactant to the anionic surfactant is 1:8 to 40 to optimize charge balance and micelle compactness.

[0017] Preferably, the detection limit of the system is ≤3.66×10⁻⁶. 3 Bq / mL, with a wide temperature range of 10℃~40℃, and a water capacity of 70% (volume fraction).

[0018] Preferably, the amount of the nonionic surfactant is 20-45%, more preferably 20-35%, and even more preferably 30-35%.

[0019] Preferably, the nonionic surfactant is selected from isomeric tridecyl alcohol polyoxyethylene ethers (E / TO series, such as E-1310 and TO-3, TO-8, TO-10), branched secondary alcohol polyoxyethylene ethers (SA series, such as SA-9, SA-15), nonylphenol polyoxyethylene ethers (NP / CO series, such as NP-40, CO-520 / 630 / 720), alkyl glycosides (APG series, such as APG0810, APG1214), and polyoxyethylene polyoxypropylene block copolymers (Pluronic series, ...). Such as L64, F127), polyoxyethylene polyoxypropylene glycerol ether (GPE-1025), fatty alcohol polyoxyethylene ether (AEO series, such as AEO-7, AEO-9), octylphenol polyoxyethylene ether (OP series, such as OP-10), polyoxyethylene lauryl ether (Brij series, such as Brij30, Brij52), polyethylene glycol monoalkyl ether (MPEG series, such as MPEG-200 and MPEG-400) and lauryl alcohol polyoxyethylene ether (MOA series, such as MOA-3) one or more.

[0020] More preferably, the nonionic surfactant is selected from one or more of the following: nonylphenol polyoxyethylene ether (NP-10), nonylphenol polyoxyethylene ether (NP-40), polyoxyethylene (5) nonylphenyl ether (CO-520), polyoxyethylene (9) nonylphenyl ether (CO-630), polyoxyethylene (12) nonylphenyl ether (CO-720), polyethylene glycol monoalkyl ether (TO-8), lauryl alcohol polyoxyethylene ether (MOA-3), isomeric tridecyl alcohol polyoxyethylene ether (X-100), and fatty alcohol polyoxyethylene ether (AEO-7).

[0021] Preferably, the amount of the anionic surfactant is 2-10%, more preferably 4-8%.

[0022] Preferably, the anionic surfactant is selected from one or more of sulfate esters, phosphate esters, carboxylates, alkylbenzene sulfonates, α-olefin sulfonates, succinate sulfonates, alkyl glycoside phosphates, isomeric alcohol polyoxyethylene ether phosphates, fatty alcohol polyoxyethylene ether phosphates, and alkylphenol polyoxyethylene ether phosphates.

[0023] More preferably, the anionic surfactant is selected from one or more of the following: ammonium lauryl sulfate, potassium alkylphenol ether phosphate, sodium dodecylbenzene sulfonate, sodium dioctyl succinate sulfonate, APG-1214 phosphate, isomeric tridecyl ether phosphate (TXP-5), fatty alcohol polyoxyethylene ether phosphate (AEO-3P, AEO-9P), and alkylphenol polyoxyethylene ether phosphate (APE-4P, APE-10P).

[0024] Preferably, the amount of the zwitterionic surfactant is 0.2-2%, more preferably 0.3-0.5%.

[0025] Preferably, the zwitterionic surfactant is selected from one or more of the following types: amino acid type, betaine type, imidazoline type, and amine oxide type.

[0026] More preferably, the zwitterionic surfactant is selected from one or more of cocamidopropyl betaine (CAPB), dodecyl dimethyl betaine (BS-12K), dodecyl dimethyl sulfobetaine (SDBS-12), dodecyl imidazoline sulfobetaine, and dodecyl dimethylamine oxide (OA-12).

[0027] Preferably, the co-solvent is selected from high-boiling-point polar solvents, including one or more of diethylene glycol butyl ether, diethylene glycol hexyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether, tripropylene glycol n-butyl ether, tripropylene glycol monomethyl ether, and triethylene glycol methyl ether; more preferably, the co-solvent is diethylene glycol butyl ether and tripropylene glycol n-butyl ether.

[0028] Preferably, the amount of the co-solvent is 3-20%, more preferably 4-12%, and even more preferably 8-10%; wherein the ratio of diethylene glycol butyl ether to tripropylene glycol n-butyl ether is 8-20:1.

[0029] Preferably, the solvent is selected from one or more of toluene, xylene, cyclohexane, n-hexane, 1,4-dichlorobenzene, methanol, ethanol, ethylene glycol, isopropanol, dimethyl sulfoxide, sulfolane, fluorocarbons, decahydronaphthalene, and 2,6-diisopropylnaphthalene.

[0030] More preferably, the solvent is 2,6-diisopropylnaphthalene, which has the characteristics of low fluorescence background interference, high energy transfer capability and strong tolerance to polar substances such as water and alcohols.

[0031] Preferably, the small amount of pure water may interact with the hydrophilic groups of the surfactant to stabilize the mixed micelle structure, adjust the hydrophilic-hydrophobic balance to enhance solubility, and at the same time help the cosolvent exert its effect, adjust the properties of the main solvent, and enhance the stability and flowability of the system.

[0032] Preferably, the preparation method of the above-mentioned multi-surfactant synergistic water-based wide-temperature-range scintillation fluid compound system includes the following steps:

[0033] (1) Under light-protected conditions at 25-30°C, the first and second scintillators are added to a mixed solvent with a volume ratio of solvent to co-solvent of 2-4:1. The mixture is stirred at a stirring rate of 400-600 rpm or under ultrasonic assistance with an ultrasonic power of 100-300 W and an ultrasonic time of 15-60 min until it is completely dissolved. The dissolution temperature is controlled at 25-30°C and the dissolution time is 30-60 min.

[0034] (2) Add nonionic surfactant → amphoteric surfactant → anionic surfactant in sequence according to the ratio. The interval between each type of surfactant is 10 to 15 minutes. At the same time, maintain the stirring rate at 400 to 600 rpm to form a homogeneous solution system. The water-based wide temperature range scintillation liquid compound system with synergistic effect of multiple surfactants can be obtained.

[0035] Preferably, in step (1), the dissolution step ensures that the scintillator is completely dissolved by temperature-controlled stirring, thus avoiding degradation of the scintillator due to local overheating.

[0036] Preferably, the ultrasonic assistance is used to achieve rapid and uniform dispersion of the scintillator.

[0037] Preferably, in step (2), the surfactants are added in the order of nonionic surfactant → amphoteric surfactant → anionic surfactant. The formation efficiency of the interfacial adsorption layer is optimized by the gradient addition order, thereby improving the uniformity of the system.

[0038] Preferably, the water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants can be further supplemented with 0.1-0.5% antioxidant to improve long-term storage stability.

[0039] Preferably, by regulating the polymer chain length of the nonionic surfactant and precisely controlling the hydrophilic-lipophilic balance (HLB) value, the surface tension reduction efficiency of the liquid is optimized, achieving efficient connection between the scintillation phase and the aqueous monolayer of the radioactive nuclide, and optimizing the solubilization ability of the aqueous phase.

[0040] Preferably, the anionic surfactant reduces the interfacial tension between different phases in the system, promotes uniform dispersion of each component, effectively avoids phase separation, and ensures the stability of the scintillation fluid performance.

[0041] Preferably, the zwitterionic surfactant can further fine-tune the overall HLB value of the system by adjusting the degree of dissociation of its charged groups, while the degree of dissociation of its charged groups can change with temperature, thereby dynamically adjusting the stability of the micelle structure over a wide temperature range.

[0042] Preferably, the cosolvent function is to adjust the polarity of the system and bind to the scintillator molecules through hydrogen bonding, thereby improving the dissolution rate and dispersion uniformity of the scintillator and avoiding a decrease in fluorescence efficiency due to insufficient dissolution.

[0043] Furthermore, the scintillator functions as an energy trap and fluorescence converter; the first scintillator absorbs radiant energy, and the second scintillator transfers the wavelength to the visible light region. The nonionic surfactant forms a mixed micelle core, adjusts the HLB value, and enhances the solubility of the aqueous phase. The anionic surfactant and the zwitterionic surfactant work synergistically with the nonionic surfactant to stabilize the micelle interface charge. The cosolvent optimizes solvent compatibility, and the solvent, as the main solvent, needs to have a low fluorescence background. The water optimizes the stability of the micelle structure.

[0044] This application also claims a radioactive detection sensor for implementing the above detection method, comprising: a sample reaction module for mixing and stirring the water sample with the scintillation fluid compound system in a proportion;

[0045] The temperature control module is used to maintain the temperature of the mixed liquid after the reaction within a wide temperature range of 10℃ to 40℃.

[0046] The optical detection module includes a photomultiplier tube for receiving scintillation light signals, with an operating voltage of 800–1200V;

[0047] The signal processing module is used to perform multi-channel pulse analysis on the acquired optical signals and calculate the radioactivity concentration.

[0048] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0049] 1. The scintillation fluid compound system of the present invention can be applied to multiple fields such as nuclear medicine diagnosis, environmental pollution monitoring, nuclear waste monitoring and treatment, radiation safety detection and scientific research. In particular, for complex samples such as biological body fluids with water content ≤70% and industrial wastewater, it can be directly detected without extraction pretreatment, meeting the needs of accurate detection with a wide temperature range (10℃~40℃) and high compatibility in multiple scenarios.

[0050] 2. This invention uses the low-toxicity solvent 2,6-diisopropylnaphthalene (LD50) 50 (>5000mg / kg, compliant with EU REACH standards) This product replaces traditional toxic aromatic hydrocarbons and, combined with a synergistic blend of multiple surfactants, achieves three major performance breakthroughs: 70% aqueous phase volume capacity (80% higher than imported products), and stable without stratification within a temperature range of 10℃~40℃. 3 H detection limit as low as 3.66×10 - 3 Bq / mL; it also has non-flammable and low volatility properties, balancing high performance and environmental friendliness;

[0051] 3. This invention uses domestically produced high-purity reagents to construct the formula, which has excellent performance and lower cost compared to imports, significantly enhancing market competitiveness. The preparation process is simple and easy to implement, suitable for the production needs of large, medium and small enterprises, promoting technological innovation in related domestic industries, accelerating the progress of scientific research projects, and providing an efficient and economical solution for enhancing my country's international competitiveness in the field of radioactive detection. Attached Figure Description

[0052] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0053] Figure 1 This is the ultraviolet absorption spectrum of the scintillation fluid compound system of Example 1 of the present invention;

[0054] Figure 2 This is the fluorescence emission spectrum of the scintillation fluid compound system of Example 1 of the present invention;

[0055] Figure 3 This is a test diagram of the water holding capacity of the scintillation fluid compound system of Example 1 of the present invention and the imported Ultima Gold LLT scintillation fluid;

[0056] Figure 4 This is a temperature stability test chart of the scintillation fluid compound system of Example 1 of the present invention and the imported Ultima Gold LLT scintillation fluid;

[0057] Figure 5 This is a diagram showing the quenching standard curve of Embodiment 1 of the present invention;

[0058] Figure 6 These are test diagrams of the scintillation liquid water holding capacity of Embodiment 1 and Comparative Examples 1 to 6 of the present invention. Detailed Implementation

[0059] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0060] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0061] Example 1

[0062] See appendixFigure 1 -Appendix Figure 6 This embodiment provides a method for radioactivity detection using a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants, comprising the following steps:

[0063] S1. Sample preparation: Take a water sample or a high-aqueous phase sample containing the target radionuclide. No dehydration or organic phase extraction is required.

[0064] S2. Scintillation fluid mixing: The sample of the target radionuclide is mixed with the water-based wide temperature range scintillation fluid compound system with the synergistic effect of multiple surfactants at a volume ratio of 1:1, and stirred at 300 r / min for 20 seconds to form a uniform, clear and stable dispersion system.

[0065] S3. Setting detection conditions: Transfer the homogeneous dispersion system obtained in step S2 into a liquid scintillation counter bottle, place it in a liquid scintillation counter, set the detection temperature to 30℃, the photomultiplier tube voltage to 1000V, and the counting time to 5 minutes.

[0066] S4. Signal Acquisition and Analysis: The scintillation light signal is acquired by a liquid scintillation counter, and after processing by a multichannel pulse analyzer, the activity concentration of the target radionuclide is calculated.

[0067] The scintillator is composed of a first scintillator and a second scintillator, wherein the first scintillator is 2,5-diphenyloxazole (PPO) and the second scintillator is 1,4-bis(2-methylstyryl)benzene (bis-MSB);

[0068] The nonionic surfactant is polyoxyethylene (5) nonylphenyl ether (CO-520);

[0069] The anionic surfactant is alkylphenol polyoxyethylene ether phosphate APE-10P;

[0070] The zwitterionic surfactant is dodecyl dimethyl betaine;

[0071] The co-solvent is selected from high-boiling-point polar solvents, and the co-solvent is diethylene glycol butyl ether and tripropylene glycol n-butyl ether;

[0072] The solvent is 2,6-diisopropylnaphthalene;

[0073] The preparation method of the above-mentioned multi-surfactant synergistic water-based wide-temperature-range scintillation fluid compound system includes the following steps:

[0074] (1) Under light-protected conditions at 25°C, 0.5g of the first scintillator PPO and 0.05g of the second scintillator bis-MSB were added to a mixed solvent consisting of 8g of 2,6-diethylpropylnaphthalene, 2g of diethylene glycol butyl ether, 0.25g of tripropylene glycol n-butyl ether and 0.5g of pure water, respectively, and stirred at 500rpm for 30min until completely dissolved;

[0075] (2) Then add 7g of nonionic surfactant polyoxyethylene (5) nonylphenyl ether (CO-520), 0.1g of amphoteric surfactant dodecyl dimethyl betaine and 1.6g of anionic surfactant alkylphenol polyoxyethylene ether phosphate APE-10P in sequence. The interval between each type of surfactant is 12min. At the same time, the stirring speed is maintained at 500rpm to form a homogeneous solution system, and the water-based wide temperature range scintillation liquid compound system with synergistic effect of multiple surfactants can be obtained.

[0076] Various tests were conducted on the water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants prepared in Example 1, as detailed below:

[0077] Test 1: Absorption Spectrum Test: A test stock solution was prepared by diluting the self-developed scintillation fluid from Example 1 100 times. During the test, the stock solution was diluted 100 times and placed in a fluorescent cuvette. The absorption spectrum of the new scintillation fluid system was measured using a UV spectrophotometer. Figure 1 As shown.

[0078] Test 2: Fluorescence emission spectrum test: A test stock solution was prepared by diluting the self-developed scintillation fluid from Example 1 100 times. During the test, the stock solution was diluted 100 times and placed in a fluorescence cuvette. The fluorescence emission spectrum of the newly developed scintillation fluid system was measured using a fluorescence spectrophotometer. Figure 2 As shown.

[0079] Test 3: Water Holding Capacity Test: The water holding capacity of the self-developed scintillation fluid and the imported Ultima Gold LLT scintillation fluid of this invention was tested. The scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid were mixed with distilled water in different proportions. The corresponding water content at which milky white turbidity appeared was observed, which indicates the maximum water holding capacity of the two scintillation fluids. Figure 3 As shown, the maximum water capacity of the new scintillation fluid system is about 70%, while the maximum water capacity of the imported Ultima GoldLLT scintillation fluid is only about 40%.

[0080] Test 4: Temperature Stability Test: Temperature stability test of the self-developed scintillation fluid of this invention and the imported Ultima Gold LLT scintillation fluid: Take 0.5 mL each of the scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid, and add 0.5 mL of water to prepare colorless and transparent homogeneous solutions. Place the two homogeneous solutions in water baths at 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ and 40℃ respectively. Figure 4 As shown, the novel scintillation fluid system of this invention maintains a clear and transparent homogeneous solution state throughout the entire temperature range of 10℃ to 40℃, exhibiting excellent wide-temperature stability. In contrast, the imported UltimaGold LLT scintillation fluid exhibits obvious turbidity and stratification at 40℃, with a sharp drop in transmittance, indicating that its high-temperature adaptability has significant defects.

[0081] Test 5: Plotting the quenching standard curve: using PerkinElmer. 3 H standard sources (10 series quenched and 1 unquenched source) were used to detect sources with known activity using an ultra-low background liquid scintillation spectrometer (LSA-3000) with a built-in high-resolution radioactivity detection sensor. Eleven different efficiency count values ​​were obtained based on the ratio of the detected activity to the known activity of the source. Furthermore, quenching relationship curves were obtained based on the TDCR value (triple detection efficiency ratio, which measures the triple coincidence and double coincidence count rates of three PMTs, i.e., Nt and Nd; TDCR is the ratio of the three-tube to two-tube coincidence count rates, Nt / Nd). Figure 5 As shown.

[0082] Test 6: Detection Efficiency (E%) Test: Detection efficiency (E%) test of the self-developed scintillation fluid of this invention and the imported Ultima Gold LLT scintillation fluid: Take 20 mL each of the scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid, and place them in a low-background fluorescent glass bottle for testing. Add 100 Bq of radioactive solution dissolved in n-hexadecane to each bottle. 3 H is used as the radiation source; the counting efficiency measurements of the self-developed scintillation fluid and the imported Ultima Gold LLT scintillation fluid of this invention are shown in Table 1. According to the measured TDCR value, when substituted into the FSI quenching relationship curve prepared in test 5, the counting efficiencies of the scintillation fluids are 57.68% and 56.56%, respectively; the prepared novel scintillation fluid has higher detection efficiency.

[0083] Table 1

[0084]

[0085]

[0086] Test 7: Background (Nd) Test: Background (Nd) test of the self-developed scintillation fluid of this invention and the imported Ultima Gold LLT scintillation fluid: Take 20 mL each of the scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid, put them into a low background fluorescence glass bottle for testing, and then put it into an LSA-3000. Select the counting analysis and CPM measurement mode. Then enter the energy spectrum analysis interface, select start, and the instrument starts fully automatic measurement. The background values ​​of the self-developed scintillation fluid and the imported LLT scintillation fluid under natural conditions are 20.83 cpm and 20.69 cpm, respectively. The background value of the self-developed new scintillation fluid is almost the same as that of the imported Ultima Gold LLT scintillation fluid.

[0087] Test 8: Detection Limit (MDA) Test: The detection limit (MDA) test of the self-developed scintillation fluid of the present invention and the imported Ultima Gold LLT scintillation fluid: 12 mL of the scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid were dissolved in 8 mL of water and placed in a low-background fluorescence glass bottle for testing. Then, following the steps of Test 6 and Test 7, the detection efficiency and background value of the scintillation fluid were measured over a long period of time (above 1000 min). The detection limit measurements of the self-developed scintillation fluid of the present invention and the imported Ultima Gold LLT scintillation fluid are shown in Table 2.

[0088] Table 2

[0089]

[0090] Calculated according to internationally recognized formulas:

[0091]

[0092] The value of K is related to the specified precision, and is usually taken as 3, T s and T b Measurement times for the sample and background, respectively; n b is the background count rate (cpm), E% is the counting efficiency, and V (mL) is the actual volume of the pure test sample.

[0093] When the sample measurement time is long, (K / T) can be omitted. s ) 2 If we take K=3, the formula further simplifies to:

[0094]

[0095] By substituting the values, the detection limits of the self-developed scintillation fluid and the imported Ultima Gold LLT scintillation fluid can be calculated to be 3.66 Bq / L and 4.89 Bq / L, respectively. The self-developed scintillation fluid has a lower detection limit than the imported Ultima Gold LLT scintillation fluid.

[0096] Test 9: Anti-quenching ability test: Anti-quenching ability test of the self-developed scintillation fluid of the present invention and the imported Ultima Gold LLT scintillation fluid: Take 20 mL each of the scintillation fluid prepared in Example 1 and the imported Ultima Gold LLT scintillation fluid, put them into a low background fluorescence glass bottle for testing, and add 100 Bq of radioactive solution dissolved in n-hexadecane. 3 H is used as a radioactive source for nuclide selection measurement. 3 H, and each added 50 μL of carbon tetrachloride as a quenching agent; the counting efficiency measurements of the self-developed scintillation fluid and the imported Ultima Gold LLT scintillation fluid after adding the quenching agent are shown in Table 3. According to the measured TDCR value, when substituted into the FSI quenching relationship curve prepared in Test 5, it can be concluded that the counting efficiencies of the self-developed scintillation fluid and the imported Ultima Gold LLT scintillation fluid after adding the quenching agent are 33.75% and 33.54%, respectively, and there is no significant difference in their anti-quenching performance.

[0097] Table 3

[0098] Sample name Nt Nd TDCR E％ Self-made scintillation solution 1237.21 3792.02 0.3263 33.75 Imported Ultima Gold LLT scintillation solution 1122.39 3563.75 0.3149 33.54

[0099] Comparative Example 1

[0100] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0101] Only nonionic surfactants were added in this comparative example.

[0102] Comparative Example 2

[0103] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0104] Only zwitterionic surfactants were added in this comparative example.

[0105] Comparative Example 3

[0106] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0107] Only anionic surfactants were added in this comparative example.

[0108] Comparative Example 4

[0109] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0110] In this comparative example, only nonionic surfactants and amphoteric surfactants were added.

[0111] Comparative Example 5

[0112] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0113] Only amphoteric and anionic surfactants were added in this comparative example.

[0114] Comparative Example 6

[0115] This comparative example is based on Example 1 above, and the similarities with Example 1 above will not be repeated.

[0116] In this comparative example, only nonionic and anionic surfactants were added.

[0117] The components and amounts added in Example 1 and Comparative Examples 1 to 6 are listed in Table 4.

[0118] Table 4

[0119]

[0120]

[0121] Using the test method described in Test 3, the water-holding capacity of the scintillation fluids of Example 1 and Comparative Examples 1 to 6 was tested. Strictly following the "water-holding capacity test method" in Test 3, at room temperature of 25°C, an equal volume of deionized water was added to each comparative example scintillation fluid system and the scintillation fluid of the self-developed example, so that the volume ratio of the water phase reached 50%. By comparing and observing the turbidity of the system and the phase separation phenomenon, the differences in the solubilization capacity of different surfactant compounding schemes on the water phase were evaluated.

[0122] Figure 6 The comparison of the water-holding capacity of Example 1 and Comparative Examples 1 to 6 is presented visually. At room temperature (25°C), Example 1 was clear and transparent with no stratification or turbidity at 50% water content; while Comparative Examples 1 to 6 all showed significant turbidity and stratification at 50% water content, with white flocculent precipitates visible in the system. This experimental phenomenon clearly demonstrates that the comparative scintillation fluids formulated with single or binary surfactants cannot effectively solubilize the aqueous medium, while the multi-surfactant synergistic formulation system proposed in this invention constructs a more stable supramolecular micelle network, significantly improving the water-holding capacity of the scintillation fluid.

[0123] The above results effectively verify the uniqueness and innovation of the compound design of this invention in overcoming traditional technical bottlenecks. It not only breaks through the technical limitations of traditional single / binary surfactant systems in terms of water capacity and temperature stability, but also achieves a significant improvement in detection efficiency under conditions with high aqueous phase content, providing a novel material solution for the field of radiation detection that combines environmental adaptability and detection reliability.

[0124] In summary, the scintillation fluid compound system of this invention is applicable to multiple fields such as nuclear medicine diagnostics, environmental pollution monitoring, nuclear waste monitoring and treatment, radiation safety detection, and scientific research. Especially for complex samples such as biological fluids with a water content ≤70% and industrial wastewater, it allows for direct detection without extraction pretreatment, meeting the requirements for accurate detection over a wide temperature range (10℃~40℃) and with high compatibility in various scenarios. This invention uses the low-toxicity solvent 2,6-diisopropylnaphthalene (LD50) 50 (>5000mg / kg, compliant with EU REACH standards) This product replaces traditional toxic aromatic hydrocarbons and, combined with a synergistic blend of multiple surfactants, achieves three major performance breakthroughs: 70% aqueous phase volume capacity (80% higher than imported products), and stable without stratification within a temperature range of 10℃~40℃. 3 H detection limit as low as 3.66×10 -3 Bq / mL; it also possesses non-flammability and low volatility, balancing high performance and environmental friendliness; this invention uses domestically produced high-purity reagents to construct the formula, resulting in excellent performance and lower costs compared to imports, significantly enhancing market competitiveness; the preparation process is simple and easy to implement, adaptable to the production needs of large, medium, and small enterprises, promoting technological innovation in related domestic industries, accelerating the progress of scientific research projects, and providing an efficient and economical solution for enhancing my country's international competitiveness in the field of radioactive detection.

[0125] The above-described embodiments are merely one implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for detecting radioactivity in a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants, characterized in that, Includes the following steps: S1. Sample preparation: Take a water sample containing the target radionuclide. No dehydration or organic phase extraction is required. S2. Scintillation fluid mixing: The sample of the target radionuclide is mixed with a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants at a volume ratio of 1:1, and stirred at a speed of 200~300r / min for 10~30 seconds to form a uniform, clear and stable dispersion system. S3. Setting detection conditions: Transfer the homogeneous dispersion system obtained in step S2 into a liquid scintillation counter bottle, place it in a liquid scintillation counter, set the detection temperature to 10℃~40℃, the photomultiplier tube voltage to 800~1200V, and the counting time to 1~10 minutes. S4. Signal Acquisition and Analysis: The scintillation light signal is acquired by a liquid scintillation counter, and after processing by a multichannel pulse analyzer, the activity concentration of the target radionuclide is calculated. The water-based wide-temperature-range scintillation fluid compound system, comprising multiple surfactants with synergistic effects, includes the following components by mass percentage: Scintillator 1-5%, nonionic surfactant 20-45%, anionic surfactant 2-10%, amphoteric surfactant 0.2-2%, cosolvent 3-20%, solvent 30-50%, water 0.5-3%; The scintillator is composed of a first scintillator and a second scintillator. The first scintillator is selected from one or more of 2,5-diphenyloxazole, 2-phenyloxazole, 2,5-di(4-methylphenyl)oxazole, parabenzylbenzene, and 2-phenyl-5-(4-diphenyl)-1,3,4-oxazole. The second scintillator is selected from one or more of 1,4-bis(2-methylstyryl)benzene, 1,4-bis[2-(5-phenyl)oxazolyl]benzene, 1,4-bis[2-(4-methyl-5-phenyloxazolyl)]benzene, and 2-(4'-diphenyl)-6-phenylbenzoxazole. The amount of the second scintillator in the scintillator is 5% to 20%.

2. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The mass ratio of the zwitterionic surfactant to the anionic surfactant is 1:8~40.

3. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The detection limit of the system is ≤3.66×10⁻ 3 Bq / mL, with a wide temperature range of 10℃~40℃, and a water capacity of up to 70%.

4. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The nonionic surfactant is selected from one or more of the following: isotridecyl alcohol polyoxyethylene ether, branched secondary alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, alkyl glycoside, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene polyoxypropylene glycerol ether, fatty alcohol polyoxyethylene ether, octylphenol polyoxyethylene ether, polyoxyethylene lauryl ether, polyethylene glycol monoalkyl ether, and lauryl alcohol polyoxyethylene ether.

5. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The anionic surfactant is selected from one or more of the following: sulfate esters, phosphate esters, carboxylates, alkylbenzene sulfonates, α-olefin sulfonates, succinate sulfonates, alkyl glycoside phosphates, isomeric alcohol polyoxyethylene ether phosphates, fatty alcohol polyoxyethylene ether phosphates, and alkylphenol polyoxyethylene ether phosphates.

6. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The zwitterionic surfactant is selected from one or more of the following types: amino acid type, betaine type, imidazoline type, and amine oxide type.

7. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The co-solvent is selected from high-boiling-point polar solvents, including one or more of diethylene glycol butyl ether, diethylene glycol hexyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether, tripropylene glycol n-butyl ether, tripropylene glycol monomethyl ether, and triethylene glycol methyl ether.

8. The method for radioactivity detection of a water-based wide-temperature-range scintillation fluid compound system with synergistic effects of multiple surfactants as described in claim 1, characterized in that, The solvent is selected from one or more of toluene, xylene, cyclohexane, n-hexane, 1,4-dichlorobenzene, methanol, ethanol, ethylene glycol, isopropanol, dimethyl sulfoxide, sulfolane, fluorocarbons, decahydronaphthalene, and 2,6-diisopropylnaphthalene.

9. A radioactive detection sensor for implementing the detection method according to any one of claims 1 to 8, characterized in that, include: The sample reaction module is used to mix and stir the water sample with the scintillation fluid compound system in a certain proportion. The temperature control module is used to maintain the temperature of the mixed liquid after the reaction within a wide temperature range of 10℃ to 40℃. The optical detection module includes a photomultiplier tube for receiving scintillation light signals, with an operating voltage of 800~1200V; The signal processing module is used to perform multi-channel pulse analysis on the acquired optical signals and calculate the radioactivity concentration.

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