CN107167834B - Detect the SERS active-substrate and its preparation method and application of thermoneutron radiation - Google Patents

Abstract

The invention discloses a SERS active substrate for detecting thermal neutron radiation. The SERS active substrate for detecting thermal neutron radiation is obtained by modifying a surface-enhanced Raman active substrate with thermal neutron radiation responsive molecules to the surface of an aminated glass slide. obtained base. The invention also discloses the preparation method and application of the SERS active substrate for detecting thermal neutron radiation. The present invention effectively utilizes the characteristics of nanometer materials, and uses a Raman spectrometer for detection, which greatly reduces the detection cost. The present invention has the advantages of low cost, rapidity, simplicity, sensitivity and good repeatability. Probes based on surface-modified thermal neutron radiation responsive molecules are sensitive to thermal neutrons and produce SERS changes, which can realize rapid detection of thermal neutron radiation.

Description

SERS active substrate for detecting thermal neutron radiation and its preparation method and application

technical field

The invention belongs to the technical field of SERS sensing, and in particular relates to a SERS active substrate for detecting thermal neutron radiation, a preparation method and application thereof.

technical background

Neutrons can have a small, hard-to-detect charge and can be thought of as neutral particles, slightly more massive than protons. Express neutron: the energy is between 10MeV and 50MeV. in:

Fast neutrons: the energy is between 0.5MeV and 10MeV.

Medium-energy neutrons: the energy is between 1keV and 0.5MeV.

Slow neutrons: energy between 0 and 1keV, including epithermal neutrons, thermal neutrons, cold neutrons and resonant neutrons. Among them, thermal neutrons with an energy of about 0.025eV are called thermal neutrons. With the vigorous development of nuclear technology, neutron radiation has gradually entered human life. On the one hand, nuclear technology is used for cancer radiotherapy, power generation, etc.; on the other hand, nuclear radiation poses serious pollution and threats to living organisms and nature. Therefore, its precise detection and effective control are very important.

The most suitable boron trifluoride proportional counter tube for measuring thermal neutrons is filled with ¹⁰ BF ₃ gas, commonly known as ¹⁰ BF ₃ counter tube. After the neutron enters the counting tube, it undergoes (n, α) nuclear reaction with boron; in addition, the scintillator of the ¹⁰ boron scintillation counting tube is ZnS(Ag) plus boron compound, and the (n, α) nuclear reaction is used to detect neutrons; There are ³ He counter tubes, which are made by using the principle of nuclear reaction (n, p) of neutrons and helium.

Surface-enhanced Raman scattering (SERS), as a spectroscopic analysis technique with development potential, has been applied in various fields such as chemistry, physics, biology, medicine, environmental monitoring, and public safety. Non-toxic, non-destructive, high sensitivity and strong reproducibility are its great advantages. Therefore, the combination of Raman techniques holds great promise in the evaluation of thermal neutron radiation processes.

Contents of the invention

Purpose of the invention: The technical problem to be solved by the present invention is to provide a SERS active substrate for detecting thermal neutrons.

The technical problem to be solved by the invention is to provide a method for preparing a SERS active substrate for detecting thermal neutrons.

The technical problem to be solved by the present invention is to provide the application of the SERS active substrate for detecting thermal neutrons in detecting thermal neutron radiation.

The technical problem to be solved by the present invention is to provide a material for detecting thermal neutron radiation.

The final technical problem to be solved by the present invention is to provide a method for detecting thermal neutron radiation.

Technical solution: In order to solve the above technical problems, the present invention provides that the SERS active substrate for detecting thermal neutrons is a surface-enhanced Raman active substrate with thermal neutron radiation responsive molecules.

Specifically, it is a substrate obtained by modifying the above surface-enhanced Raman active substrate with thermal neutron radiation responsive molecules to the surface of an aminated glass slide.

Wherein, the above thermal neutron radiation responsive molecule is one or more of 3-mercaptobenzene ¹⁰ boronic acid, 4-mercaptobenzene ¹⁰ boronic acid, 3-aminobenzene ¹⁰ boronic acid or 4-aminobenzene ¹⁰ boronic acid.

Wherein, the above-mentioned surface-enhanced Raman active substrate is a single element of gold, silver, copper or a liquid phase suspension of multiple elements compounded or a liquid phase suspension modified by a single element or multiple elements of gold, silver, copper A solid surface-enhanced Raman active substrate obtained on the surface of a solid support.

Wherein, the surface-enhanced Raman active substrate is a gold nanoshell probe, and the diameter of the gold nanoshell in the gold nanoshell probe is 100 nm to 300 nm.

Preferably, the diameter of the gold nanoshell in the above gold nanoshell probe is 165-175 nm.

The content of the present invention also includes the preparation method of the above-mentioned SERS active substrate for detecting thermal neutrons, comprising the following steps:

1) Preparation of surface-enhanced Raman active substrate: the surface-enhanced Raman active substrate is a single element of gold, silver, copper or a liquid phase suspension compounded by multiple elements or a single element or multiple elements of gold, silver, copper The liquid-phase suspension compounded by the two elements is modified on the surface of the solid-phase carrier to obtain a solid-phase surface-enhanced Raman active substrate;

2) Preparation of a surface-enhanced Raman active substrate for detecting thermal neutron radiation: modifying thermal neutron radiation-responsive molecules in a surface-enhanced Raman active substrate to obtain a SERS active substrate for detecting thermal neutron radiation.

Specifically, the preparation method based on the active substrate of the gold nanoshell probe for detecting thermal neutrons comprises the following steps:

1) Preparation of gold nanoshells;

2) Preparation of probes: modifying molecules responsive to thermal neutron radiation on the surface of gold nanoshells to obtain gold nanoshell probes for detecting thermal neutron radiation;

3) Preparation of the SERS active substrate of the gold nanoshell probe for detecting thermal neutron radiation: modify the gold nanoshell probe for detecting thermal neutron radiation to the surface of an aminated glass slide, and fully wash it to prepare a ready-to-use detection substrate. SERS-active substrates for thermal neutron-irradiated gold nanoshell probes.

Specifically, the preparation method of the SERS active substrate of the gold nanoshell probe for detecting thermal neutron radiation is as follows: prepare different concentrations of gold nanoshell probe suspensions with thermal neutron radiation responsive molecules; After co-incubating the needle suspension with the aminated glass slides, they were fully washed with deionized water, dried naturally, and then detected by SERS. The group with the most stable ratio of SERS characteristic peak intensities was selected as the optimal condition.

Wherein, the ratio of the intensity of the characteristic peak is the ratio of the intensity at 1574 cm ^-1 to that at 1585 cm ^-1 .

Wherein, the above thermal neutron radiation responsive molecule is one or more of 3-mercaptobenzene ¹⁰ boronic acid, 4-mercaptobenzene ¹⁰ boronic acid, 3-aminobenzene ¹⁰ boronic acid or 4-aminobenzene ¹⁰ boronic acid.

The content of the present invention also includes the application of the above-mentioned SERS active substrate for detecting thermal neutrons in detecting thermal neutron radiation.

The content of the present invention also includes a material for detecting thermal neutron radiation, which includes the SERS active substrate for detecting thermal neutron radiation.

The content of the present invention also includes a method for detecting thermal neutron radiation. The detection method is to expose the SERS active substrate for detecting thermal neutron radiation to radiation aperture moderation of the neutron radiation source by paraffin and lead block. The neutron source aperture after the absorption of γ-ray and γ-ray is taken out to measure its surface-enhanced Raman spectrum, and the intensity or dose of neutron radiation can be calculated according to the ratio of the characteristic spectral line intensity.

Wherein, the above-mentioned environment to be tested is different radiation time or different distances in the neutron radiation source.

Wherein, the method for detecting the neutron radiation process based on SERS is as follows: obtain the base SERS spectrum and the SERS spectrum of the probe, and compare and prove that there is no difference; according to the ratio of the characteristic peak intensity in the base SERS spectrum and the The corresponding relationship between thermal neutron radiation time and radiation distance, data processing, and the relationship between the relative intensity ratio of the SERS spectrum of the substrate in the process are summarized.

The working principle of the present invention: the present invention utilizes thermal neutron radiation-sensitive signal molecules with obvious SERS signals, and modifies them on the surface of gold nanoshells to obtain probes. The diameter of the gold nanoshell is 165-175nm, and the gold nanoshell with a diameter within this range has a strong resonance for the 785nm laser. Among them, the probe based on surface-modified 4-mercaptobenzene ¹⁰ boronic acid is sensitive to thermal neutron radiation and produces SERS changes, which can realize the evaluation of thermal neutron radiation intensity; based on this principle, combined with the cheap and Rapid preparation, combined with rapid and cost-effective detection of thermal neutron radiation. Through the evaluation of different radiation times and radiation distances, the relative intensity changes of a series of SERS characteristic peaks are obtained, and the detection of the neutron radiation process is realized.

Beneficial effect: compared with the prior art, the present invention has the following advantages:

(1) In the present invention, after the gold nanoshell probe is assembled on the surface of the functionalized glass slide, it interacts with the radiated thermal neutrons, and the SERS signal changes significantly with time and the change of the sample to realize thermal neutron detection The evaluation of the spectroscopic detection method improves the accuracy of thermal neutron detection through the moderation of the radiation aperture of the neutron radiation source and the absorption of gamma rays by paraffin and lead block.

(2) The present invention effectively utilizes the characteristics of nanomaterials and uses Raman spectrometer for detection, which greatly reduces the detection cost. The present invention has the advantages of low cost, fast, simple, sensitive and good repeatability. Probes based on surface-modified thermal neutron radiation-responsive molecules react sensitively to thermal neutrons and produce SERS changes, which can realize the evaluation of thermal seed radiation; based on this principle, combined with the cheap and rapid preparation of SERS active substrates, the two The combination of the two enables fast and cost-effective detection of neutron radiation. Through the evaluation of different radiation times and radiation distances, the relative intensity changes of a series of SERS characteristic peaks are obtained, and the detection of the neutron radiation process is realized.

Description of drawings

Figure 1 shows the schematic diagram of the gold nanoshell probe-based SERS active substrate for detecting thermal neutron radiation. The figure illustrates the preparation process and detection process of the substrate;

Figure 2 shows the scanning electron microscope picture of the prepared gold shell, the scanning electron microscope picture of the constructed substrate, the Raman characterization diagram of the preparation process of the thermal neutron-responsive SERS substrate, and the uniformity evaluation diagram of the prepared base;

Figure 3 shows the comparison of the SERS spectrum of the probe based on the gold nanoshell substrate and the SERS spectrum of the idealized radiation after the probe is completely reacted;

Figure 4 shows the SERS detection results after the thermal neutron detection substrate is irradiated in the neutron radiation source for different times and the change line graph of the corresponding relative intensity;

Figure 5 shows the thermal neutron detection substrate at different radiation distances in the neutron radiation source, the SERS detection results after 20 minutes of radiation and the line graph of the change of the corresponding relative intensity;

Figure 6 shows a comparison of the SERS spectrum of the probe molecule based on the silver nanoshell substrate and the SERS spectrum of the idealized radiation after the probe is completely reacted;

Fig. 7 shows the SERS detection results after the thermal neutron detection suspension is irradiated in the neutron radiation source for different times and the line graph of the change of the corresponding relative intensity.

Detailed ways

Example 1 Synthesis of gold nanoshells and construction of solid-phase surface-enhanced Raman active substrates

1. Synthesis of gold nanoshells:

First, carry out amination modification on the surface of _SiO2 with a diameter of about 110nm and adsorb 2-3nm gold nanoparticles to form composite particles. The formed composite particles are the precursors for the growth of gold nanoshells; then use hydrogen peroxide as the reducing agent, Under the catalysis of the surface of the precursor, the chloroauric acid is continuously reduced and deposited on the surface, thereby forming a complete gold nanoshell with a certain thickness. Then centrifuge at 3000rpm for 10min, discard the supernatant, collect the precipitate, resuspend to obtain a gold nanoshell suspension (OD _700nm = 1.0), and store in the dark for future use. The diameter of the gold nanoshell is 165-175nm, and the gold nanoshell with a diameter within this range has a strong resonance to the laser of 785nm (the nanomaterial can also be prepared by other methods except this embodiment).

2. Preparation of solid-phase surface-enhanced Raman active substrate:

Take a volumetric flask with a volume of 100mL, add 15.4g of 4-mercaptobenzene ¹⁰ boronic acid dissolved in 100mL of 10% ethanol aqueous solution, and ultrasonically mix. Common commercial glass slides were washed with ethanol three times for 30 minutes each time; after drying, they were immersed in 1% (v/v) aminopropyltriethoxysilane ethanol solution for 24 hours , and washed three times with ethanol. Then dry it to obtain an aminated glass slide, which is cut into small pieces with an area of 0.5 cm×0.5 cm with a glass knife. 10 μL (OD _700nm =2.0) of the above-prepared gold nanoshell suspension was taken out and dropped onto an aminated glass slide with an area of 0.5 cm×0.5 cm, and the substrate construction was completed after 30 minutes. Each piece of the substrate was placed in a centrifuge tube containing 1 mL of 4-mercaptobenzene ¹⁰ boric acid solution and soaked for 24 hours. Afterwards, the slides were taken out and washed three times with deionized water and ethanol respectively to obtain active substrates.

Principle verification:

Take a volumetric flask with a volume of 100mL, add 13.2g of sodium thiophenate dissolved in 100mL of aqueous solution to it, and mix well by ultrasonic. Common commercial glass slides were washed with ethanol three times for 30 minutes each time; after drying, they were immersed in 1% (v/v) aminopropyltriethoxysilane ethanol solution for 24 hours , and washed three times with ethanol. Then dry it to obtain an aminated glass slide, which is cut into small pieces with an area of 0.5 cm×0.5 cm with a glass knife. 10 μL (OD _700nm =2.0) of the gold nanoshell suspension was taken out and dropped onto an aminated glass slide with an area of 0.5 cm×0.5 cm, and the substrate construction was completed after 30 minutes. Each piece of the base was placed in a centrifuge tube filled with 1 mL of sodium thiophenate solution and soaked for 24 hours. Afterwards, the glass slide was taken out and washed three times with deionized water and ethanol respectively to obtain a substrate of sodium thiophenate. By comparing the SERS spectra of sodium thiophenate and 4-mercaptobenzene ¹⁰ boronic acid, the feasibility of the experiment was judged. The specific results are shown in Figure 3.

The detection experiment of embodiment 2 different neutron radiation time

For the synthesis of the neutron radiation-responsive substrate, refer to the method in Example 1, and details will not be repeated in this example.

Evaluation of solid-phase surface-enhanced Raman active substrates: the substrates were attached to the back of paraffin wax and lead block packaging blocks, placed in the radiation tunnel, and the substrates obtained by the same treatment were placed in the same position of the tunnel, and irradiated for different times each time. The radiation time is: 10 seconds, 20 seconds, 40 seconds, 60 seconds, 120 seconds, 180 seconds, 300 seconds, 600 seconds, 1200 seconds.

Experimental results: The SERS spectra of 10 randomly selected detection points on each substrate were recorded using a surface-enhanced Raman spectrometer, and the average spectrum was calculated, recorded and drawn as an integrated map, as shown in Figure 4A. From top to bottom, it corresponds to the blank group, 10 seconds, 20 seconds, 40 seconds, 60 seconds, 120 seconds, 180 seconds, 300 seconds, 600 seconds, and 1200 seconds. And according to the change of the spectrum, the relative ratio of the intensities of the reference peaks 1574cm ^-1 and 1585cm ^-1 was selected to draw a line graph as shown in Figure 4B. It can be seen from the results that the irradiated part of 4-mercaptobenzene ¹⁰ boronic acid, a natural component, is converted into thiophenol at different irradiation times. The result can be seen intuitively from the spectrogram and the line graph. In addition, when the irradiation time reaches 300 seconds or later, the spectrum does not change significantly, and the corresponding relative intensity tends to be stable, which indicates that the ¹⁰ boron contained in the substrate that can interact with thermal neutrons has been completely reacted.

The detection experiment of embodiment 3 different neutron radiation distances

For the synthesis of the substrate responding to neutron radiation, refer to the method in Example 1, which will not be repeated in this example.

Evaluation of solid-phase surface-enhanced Raman active substrates: the substrates are attached to the back of paraffin wax and lead block packaging blocks, placed in the radiation tunnel, and the substrates obtained by the same treatment are placed in different positions of the tunnels, and the distance from the stakeout point is 0cm , 2cm, 4cm, 6cm, 8cm, 10cm, each radiation time is 1200 seconds.

Experimental results: The SERS spectra of 10 randomly selected detection points on each substrate were recorded using a surface-enhanced Raman spectrometer, and the average spectra were obtained, recorded and drawn as an integrated map, as shown in Figure 5A. The corresponding radiation distances from top to bottom are 0cm, 2cm, 4cm, 6cm, 8cm, and 10cm, and according to the spectral changes, the relative ratio of the intensity of the reference peak 1574cm ^-1 to 1585cm ^-1 is selected and drawn as shown in Figure 5B line chart. It can be seen from the results that at different radiation distances, the irradiated part of the natural component 4-mercaptobenzene ¹⁰ boronic acid is converted into thiophenol in different amounts. The result can be seen intuitively from the spectrogram and the line graph. As the distance increases, the content of thiophenol on the substrate surface decreases gradually, and the rate of decrease changes from fast to slow. The results further illustrate the feasibility and sensitivity of the method.

Example 4 Synthesis of silver nanoshells and construction of solid-phase surface-enhanced Raman active substrates

1. Synthesis of silver nanoshells:

First, 25 mg of SiO ₂ nanospheres with a diameter of 110 ± 5 nm were uniformly dispersed in 13 mL of ethanol; then 1 g of polyvinylpyrrolidone was dissolved in the above solution; in 2 mL of water); then the two solutions were mixed and stirred for a few minutes; finally, the mixed solution was divided into reaction kettles and reacted at 120°C for 12 hours. After the reaction, after the reaction kettle was naturally cooled, centrifuge at 5000rpm for 2min, wash with ethanol several times to obtain the silver nanoshell suspension, and collect it into 1mL. The diameter of the silver nano shell is 165-175nm.

2. Preparation of solid-phase surface-enhanced Raman active substrate:

Take a volumetric flask with a volume of 100mL, add 15.4g of 4-mercaptobenzene ¹⁰ boronic acid dissolved in 100mL of 10% ethanol aqueous solution, and ultrasonically mix. Common commercial glass slides were washed with ethanol three times for 30 minutes each time; after drying, they were immersed in 1% (v/v) aminopropyltriethoxysilane ethanol solution for 24 hours , and washed three times with ethanol. Then dry it to obtain an aminated glass slide, which is cut into small pieces with an area of 0.5 cm×0.5 cm with a glass knife. 10 μL of the above-mentioned silver nanoshell suspension was taken out and dropped onto an aminated glass slide with an area of 0.5 cm×0.5 cm, and the substrate construction was completed after 30 minutes. Each piece of the substrate was placed in a centrifuge tube containing 1 mL of 4-mercaptobenzene ¹⁰ boric acid solution and soaked for 24 hours. Afterwards, the glass slide was taken out, and washed three times with deionized water and ethanol respectively to obtain an active substrate (except for this embodiment, other methods can also be used to prepare the nanomaterial).

Each piece of the base was placed in a centrifuge tube filled with 1 mL of sodium thiophenate solution and soaked for 24 hours. Afterwards, the glass slide was taken out and washed three times with deionized water and ethanol respectively to obtain a substrate of sodium thiophenate. By comparing the SERS spectra of sodium thiophenate and 4-mercaptobenzene ¹⁰ boronic acid, the feasibility of the experiment was judged. The specific results are shown in Figure 6. It can be seen from the results that, on the one hand, there is no significant difference between the SERS results of this type of probe molecules adsorbed on silver nanoshells and those after adsorption on gold nanoshells; The base of the shell was used in this test.

Example 5 Suspended Surface of Liquid Phase Enhanced Raman Active Substrate Experiments with Different Radiation Times

Suspended surface-enhanced Raman active substrate evaluation in liquid phase: each centrifuge tube contains 200 μL of 10% (v/v) ethanol aqueous solution of 1 mM 4-mercaptobenzene ¹⁰ boronic acid, and then takes 10 μL of the gold nanoshell prepared in Example 1 to suspend The solution was mixed with it for 24 hours. Attach the centrifuge tubes to the paraffin and lead blocks respectively, put them into the radiation channel, place them in the same position and irradiate them for different times. The radiation time is 0, 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes and 20 minutes.

Experimental results: The treated samples were centrifuged to collect the precipitates. Then centrifuge and resuspend several times to remove unadsorbed residues, and finally disperse into 10 μL of water, and then drop it on a solid-phase glass slide or silicon wafer, etc., and then record 10 random selections of each substrate by SERS spectrum point, an averaged spectrum is obtained, as shown in Figure 7A. Corresponding to the control group, 1min, 2min, 3min, 5min, 10min, 20min groups from top to bottom. According to the spectral change, the relative ratio of the reference peak intensities at 1574 cm ^-1 and 1585 cm ^-1 was chosen to draw the line graph shown in Figure 7B. By comparing the results in Figure 4, it can be seen that the sensitivity of the detection using the solid phase substrate is higher, and the required detection time is shorter.

Claims (9)

1. The SERS active substrate for detecting thermal neutron radiation is characterized in that, the SERS active substrate for detecting thermal neutron radiation is a surface-enhanced Raman active substrate with thermal neutron radiation responsive molecules, and the thermal neutron radiation responsive The molecule is one or more of 3-mercaptobenzene ¹⁰ boronic acid, 4-mercaptobenzene ¹⁰ boronic acid, 3-aminobenzene ¹⁰ boronic acid or 4-aminobenzene ¹⁰ boronic acid. 2. The SERS active substrate for detecting thermal neutron radiation according to claim 1, characterized in that, the surface-enhanced Raman active substrate is the suspension of a single element of gold, silver, copper or a composite liquid phase of multiple elements A solid-phase surface-enhanced Raman active substrate obtained by modifying a single element or multiple elements of gold, silver, and copper on the surface of a solid-phase support. 3. The SERS active substrate for detecting thermal neutron radiation according to claim 1, wherein the surface-enhanced Raman active substrate is a gold nanoshell probe, and the gold nanoshell in the gold nanoshell probe The diameter is 100nm~300nm. 4. the preparation method of the SERS active substrate of detection thermal neutron radiation described in any one of claim 1～3, is characterized in that, comprises the following steps: 1) Preparation of surface-enhanced Raman active substrate: The surface-enhanced Raman active substrate is a liquid phase suspension of a single element or multiple elements of gold, silver, and copper, or a single or multiple element of gold, silver, and copper The liquid-phase suspension compounded by the two elements is modified on the surface of the solid-phase carrier to obtain a solid-phase surface-enhanced Raman active substrate; 2) Preparation of surface-enhanced Raman active substrates for thermal neutron radiation detection: modify thermal neutron radiation-responsive molecules in surface-enhanced Raman active substrates to obtain SERS active substrates for thermal neutron radiation detection. 5. the preparation method of the SERS active substrate that detects thermal neutron radiation according to claim 4 is characterized in that, described thermal neutron radiation response molecule is 3-mercaptobenzene ¹⁰ boronic acid, 4-mercaptobenzene ¹⁰ boronic acid, 3-mercaptobenzene 10 boronic acid, - one or more of aminobenzene ¹⁰ boronic acid or 4-aminobenzene ¹⁰ boronic acid. 6. The application of the SERS active substrate for detecting thermal neutron radiation according to any one of claims 1 to 3 in detecting thermal neutron radiation. 7. A material for detecting thermal neutron radiation, characterized in that the material comprises the SERS active substrate for detecting thermal neutron radiation according to any one of claims 1 to 3. 8. A method for detecting thermal neutron radiation, characterized in that, the detection method is to expose the SERS active substrate for detecting thermal neutron radiation according to any one of claims 1 to 3 to the environment to be tested, take out Measure its surface-enhanced Raman spectrum, and calculate the intensity or dose of thermal neutron radiation according to the ratio of characteristic spectral line intensities. 9 . The method for detecting thermal neutron radiation according to claim 8 , characterized in that, the environment to be tested is a thermal neutron radiation source that radiates at different times or at different distances.