Device for detecting trace heavy metals in soil, plants and water bodies

Abstract

The utility model relates to the technical field of X-ray detection, and discloses a device for detecting trace heavy metals in soil, plants and water, which comprises a shielding layer, a control sliding table module and an X-ray total reflection system are arranged in the shielding layer, a sample inlet, a cooling fan and a horizontal slide rail are arranged on the shielding layer, a sample table can be drawn out along the horizontal slide rail, and the X-ray total reflection system is arranged on the sample table. The X-ray total reflection system comprises an X-ray tube, a light guide and a detector, and the height and angle of X-rays can be adjusted by controlling the sliding table module. According to the utility model, X-rays pass through the light guide to form an incident angle with an extremely small angle, total reflection is generated on the surface of the sample table, so that background noise generated on the sample table is greatly reduced, and meanwhile, the silicon drift detector is adopted, so that the detection capability is greatly improved, and a relatively good detection capability on trace or trace elements in soil is realized; and the mass is light, the movement and the transportation are convenient, and greater portability is provided for testers.

Description

Technical Field

[0001] This utility model relates to the field of X-ray detection technology, and in particular to a device for detecting trace heavy metals in soil, plants and water. Background Technology

[0002] With social development, heavy metal pollution and food safety issues are receiving increasing attention. Detection devices are indispensable in research on soil and water pollution, as well as the bioaccumulation of pollutants by plants.

[0003] X-ray fluorescence analysis technology has attracted much attention from scientists due to its speed and convenience. X-rays excite the characteristic fluorescence of elements in the sample, which is then recorded and analyzed by a detection device. The detection principle is simple and the actual operation is convenient. Compared with inductively coupled plasma mass spectrometry or inductively coupled plasma atomic emission spectrometry, X-ray fluorescence analysis technology has higher operability when testing the same area under the requirements of trace element concentration in soil environment. It can be used for mobile detection and rapid sample preparation without dangerous chemical reagents. The detection time and cost are huge advantages of X-ray fluorescence analysis.

[0004] However, traditional X-ray fluorescence analysis is inconvenient to operate, difficult to perform, slow to detect, low sensitive, and has a high detection limit. It is mainly used to analyze elements such as Fe, Ca, P, and S in soil with high content. It cannot detect trace or ultra-trace elements with content of 100 ppb to 100 ppm. It is generally used for semi-quantitative and qualitative analysis. In addition, traditional X-ray fluorescence analysis has a large background noise in the fluorescence signal during detection. Furthermore, existing detection devices are relatively large and inconvenient to move and transport. Utility Model Content

[0005] The purpose of this invention is to provide a device for detecting trace heavy metals in soil, plants, and water, so as to reduce the noise generated in the detection process of existing technologies, improve the detection sensitivity, simplify the operation, and make it more convenient to move and transport.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A device for detecting trace heavy metals in soil, plants, and water includes a shielding layer, a control slide module, an X-ray total reflection system, and a high-voltage power supply module. The shielding layer is a square shell with a sample inlet. An inlet baffle is located outside the sample inlet and can be opened or closed. A horizontal slide rail is located inside the shielding layer, and a sample stage is slidably mounted on the horizontal slide rail. The upper surface of the sample stage has a first groove for placing the sample, and the sample stage can be pulled out from the sample inlet. The control slide module includes a Z-axis displacement slide and a θ-axis angular displacement slide. The Z-axis displacement slide is fixed to the bottom inside the shielding layer, and the top of the Z-axis displacement slide is connected to the θ-axis angular displacement slide. The Z-axis displacement slide can push the θ-axis angular displacement slide to move up and down. An X-ray total reflection system is located on the top of the θ-axis angular displacement slide.

[0008] The X-ray total internal reflection system includes a base, an X-ray tube, a light guide, and a detector. The base is fixed to the top of an θ-axis angular displacement slide, which allows the base to swing. The X-ray tube and light guide are fixed to the base. The light guide includes an upper fixing block, a lower fixing block, two monocrystalline silicon glass pieces, and two ultra-thin tantalum metal sheets. The lower fixing block is fixed to the base, and the upper fixing block is located on top of the lower fixing block and connected by bolts. Both the upper and lower fixing blocks have grooves, which are arranged opposite each other. The two monocrystalline silicon glass pieces are respectively fixed in the grooves of the upper and lower fixing blocks. The two tantalum metal sheets are symmetrically sandwiched between the two monocrystalline silicon glass pieces, forming a narrow slit between the two monocrystalline silicon glass pieces and the two tantalum metal sheets for X-rays to pass through. The detector is located directly above the sample stage. The X-ray tube is powered by a high-voltage power supply module.

[0009] Furthermore, the trace heavy metal detection device also includes a three-channel power module. The shielding layer is equipped with an air inlet, an air outlet, and a main power interface connected to the three-channel power module. Both the air inlet and the air outlet are equipped with cooling fans. The three-channel power module supplies power to the high-voltage power module, the detector, and the cooling fans, respectively.

[0010] Furthermore, a lead rubber insulation layer is installed on the inner side of the entrance baffle.

[0011] Furthermore, the entrance baffle is connected to the shielding layer via a hinge.

[0012] Furthermore, the θ-axis angular displacement slide is electrically controlled, and the shielding layer is equipped with a controller interface that connects to the θ-axis angular displacement slide. The controller interface is used to connect an external computer to control the size of the θ angle in real time.

[0013] Furthermore, the detector employs a silicon drift detector with a resolution of 125 eV FWHM and a photosensitive area of ​​20 mm². 2 The input power supply is 5VDC.

[0014] Furthermore, two data transmission interfaces are provided on the shielding layer. The two data transmission interfaces are connected to the detector and the high-voltage power supply module, respectively, and the external computer is used for data transmission and power control, respectively.

[0015] Furthermore, the θ-axis angular displacement slide swing amplitude is ±10°, and the minimum swing angle is 0.05°.

[0016] Furthermore, Ag is used as the target material in the X-ray tube.

[0017] Furthermore, the sample stage is made of single-crystal silicon glass with a surface accuracy of λ / 10, where λ is 6332.8 nm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This utility model uses a 6101 stainless steel shielding layer as the outer shell, which can effectively prevent X-rays from penetrating the human body and causing harm when using this device. In addition, compared with the traditional X-ray fluorescence analysis method, which can only analyze elements such as Fe, Ca, P and S in high concentrations in soil, this utility model combines the principle of total internal reflection of X-rays and uses an X-ray silicon drift detector, which can significantly reduce the background noise of the fluorescence signal during use. Currently, experiments have shown that the detection limit of this utility model has reached 50 ppb, which has a good detection capability for trace or ultra-trace elements in soil.

[0020] 2. In this invention, the X-ray tube uses Ag as the target material, ensuring sensitivity to heavy metal elements while also possessing the ability to test light elements such as Na, Mg, Al, P, and S. Furthermore, its maximum power is 50W, the maximum energy of the primary X-ray is 50keV, and the maximum current reaches 1mA, ensuring the intensity of the primary X-ray. The X-ray photon beam per unit time is approximately 10¹⁴, and the detection time is generally set at 300s to ensure sufficient excitation of the sample.

[0021] 3. The sample stage of this invention uses smooth quartz glass with a flatness of less than L / 10. Only a small amount of solution or suspension sample needs to be evaporated to form an extremely thin film on the surface. Compared with other traditional testing methods, this invention is simple and time-saving to prepare sample solutions or soluble substances. It does not require carrying dangerous chemical reagents, poses no danger to non-professionals, and is easier to learn. After dissolving in pure water, take 5μL of the sample and drop it in the center of the quartz glass. Evaporate the water at 30°C and test directly. For insoluble or sparingly soluble substances, crush and sieve them using a crusher or mortar and pestle, add deionized water to make a uniformly dispersed suspension, and then take 5μL of the sample and drop it in the center of the quartz glass. Evaporate the water at 30°C and test.

[0022] 4. This utility model is equipped with both a Z-axis displacement slide and a θ-axis angular displacement slide. The θ-axis angular displacement slide is electrically controlled, which has high control precision, an swing amplitude of ±10°, and a minimum swing angle of 0.05°. It can accurately adjust the X-ray angle and height. In addition, this utility model is lightweight, easy to move and transport, and uses a 220VAC power supply, which can be directly connected to a household power supply and operated through a laptop. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the front structure of the shielding layer in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the rear structure of the shielding layer in an embodiment of the present invention;

[0025] Figure 3 This is a partial structural view of the sample inlet and inlet baffle of an embodiment of this utility model;

[0026] Figure 4 This is a schematic diagram of the X-ray total internal reflection system according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the optical guide structure according to an embodiment of the present invention;

[0028] Figure 6 This is an exploded view of the optical guide in an embodiment of this utility model;

[0029] Figure 7 This is a schematic diagram of the narrow optical guide slit in an embodiment of the present invention;

[0030] Reference numerals: 1. Shielding layer; 1-1. Sample inlet; 1-2. Air inlet; 1-3. Air outlet; 1-4. Main power interface; 1-5. Data transmission interface; 1-6. Controller interface; 2. Three-way power module; 3. High-voltage power module; 4. Inlet baffle; 5. Hinge; 6. Horizontal slide rail; 7. Sample stage; 7-1. First groove; Air inlet; 8. Cooling fan; Air outlet; 9. Lead rubber isolation layer; 10. Z-axis displacement slide; 11. θ-axis angular displacement slide; 12. Base; 13. X-ray tube; 14. Light guide; 14-1. Upper fixing block; 14-1-1. Second groove; 14-2. Lower fixing block; 14-3. Monocrystalline silicon glass; 14-4. Tantalum sheet; 14-5. Narrow slit; 15. Detector. Detailed Implementation

[0031] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] A device for detecting trace heavy metals in soil, plants, and water includes a shielding layer 1, within which a control slide module, an X-ray total reflection system, a three-way power supply module 2, and a high-voltage power supply module 3 are installed.

[0033] like Figure 1 , Figure 2 , Figure 3 As shown, the shielding layer 1 is a square shell. The front of the shielding layer 1 is provided with a sample inlet 1-1, and the rear is provided with an air inlet 1-2, an air outlet 1-3, a main power interface 1-4, two data transmission interfaces 1-5, and a controller interface 1-6. The sample inlet 1-1 is provided with an inlet baffle 4, which is connected to the shielding layer 1 by a hinge 5. The inlet baffle 4 can be opened or closed. The shielding layer 1 is also provided with a horizontal slide rail 6, on which a sample stage 7 is provided. The sample stage 7 can slide back and forth on the horizontal slide rail 6. The upper surface of the sample stage 7 is provided with a first groove 7-1 for placing the sample, and the sample stage 7 can be pulled out from the sample inlet 1-1. The groove 7-1 is used to place the sample.

[0034] In this embodiment, the shielding layer 1 is made of 6101 stainless steel with a thickness of 3mm and the external dimensions of the shielding layer 1 are 340mm×340mm×476mm. The inlet baffle 4 is made of 304 stainless steel and has a size of 110×110mm. The sample stage is made of single-crystal silicon glass with a size of 35mm×35mm×5mm and a surface accuracy of λ / 10, where λ is 6332.8nm. The groove 7-1 on the sample stage 7 has a size of 25mm×25mm and a depth of 3mm.

[0035] The two data transmission interfaces 1-5 and the controller interface 1-6 are standard network ports and standard USB ports, respectively. The main power interface 1-4 is a three-prong socket with a rated voltage of AC 220V and a rated power of 60W.

[0036] Cooling fans 8 are installed at air inlets 1-2 and air outlets 1-3 respectively. The cooling fans 8 have external dimensions of 120mm×120mm×38mm, rated voltage of 12V, rated power of 2.5w, and air intake volume of 148CFM.

[0037] The inner side of the inlet baffle 4 is provided with a lead rubber isolation layer 9 of 0.5 equivalent, and it is bonded to the inlet baffle 4 with double-sided adhesive.

[0038] like Figure 4 As shown, the control slide module includes a Z-axis displacement slide 10 and an θ-axis angular displacement slide 11. The Z-axis displacement slide 10 is fixed to the bottom of the inner side of the shielding layer 1. The top of the Z-axis displacement slide 10 is connected to the θ-axis angular displacement slide 11. The Z-axis displacement slide 10 can push the θ-axis angular displacement slide 11 to move up and down. An X-ray total internal reflection system is installed on the top of the θ-axis angular displacement slide 11. The X-ray total internal reflection system includes a base 12, an X-ray tube 13, a light guide 14, and a detector 15. The base 12 is fixed to the top of the θ-axis angular displacement slide 11, and the θ-axis angular displacement slide 11 can make the base 12 swing. The X-ray tube 13 and the light guide 14 are fixed on the base 12.

[0039] like Figure 5 , Figure 6 , Figure 7 As shown, the light guide 14 includes an upper fixing block 14-1, a lower fixing block 14-2, two monocrystalline silicon glass pieces 14-3, and two ultra-thin tantalum metal sheets 14-4. The lower fixing block 14-2 is fixed on the base, and the upper fixing block 14-1 is set on top of the lower fixing block 14-2 and connected by bolts. Both the upper fixing block 14-1 and the lower fixing block 14-2 are provided with grooves 14-1-1, and the second grooves 14-1-1 are arranged opposite to each other. The two monocrystalline silicon glass pieces 14-3 are respectively fixed in the grooves of the upper fixing block 14-1 and the lower fixing block 14-2. The two tantalum metal sheets 14-4 are symmetrically sandwiched between the two monocrystalline silicon glass pieces 14-3, and a narrow slit 14-5 is formed between the two monocrystalline silicon glass pieces 14-3 and the two tantalum metal sheets 14-4 for X-rays to pass through.

[0040] The detector 15 is positioned directly above the sample stage 7 and 2 mm away from the upper surface of the sample stage 7.

[0041] In this embodiment, the two monocrystalline silicon glass pieces 14-3 are 25mm×25mm×5mm in size, and the two pieces of tantalum metal 14-4 are 5mm×25mm×0.02mm in size. The resulting narrow slit 14-5 is 25mm×15mm×0.02mm in size. When X-rays pass through the light guide 14, the divergence angle of the X-rays can be reduced to 0.0013°.

[0042] In this embodiment, the power supply includes a three-channel power module 2 and a high-voltage power module 3. The three-channel power module 2 has three output channels with DC voltages of 5V, 24V, and 12V respectively. The three-channel power module 2 supplies power to the high-voltage power module 3, the detector 15, and the cooling fan 8 respectively. The high-voltage power module 3 supplies power to the X-ray tube 13. The high-voltage power module 3 has an input voltage of 24VDC, a maximum current of 5A, an output voltage of 0-50kV, a current of 0-2mA, a maximum power of 75W, a weight of 2.3kg, and external dimensions of 217.9mm×75.6mm×100mm.

[0043] The Z-axis displacement slide 10 is a manual displacement slide with a stroke of 20mm and an accuracy of 0.05mm. It can move the X-ray tube 13 and the light guide 14 up and down to adjust them to a suitable height.

[0044] The θ-axis angular displacement slide 11 is an electric swing slide. The θ-axis angular displacement slide 11 is connected to the controller interface 1-6. The controller interface 1-6 is used to connect to an external computer. The computer controls the size of the θ angle in real time. The swing amplitude of the θ-axis angular displacement slide 11 is ±10°, and the minimum swing angle is 0.05°.

[0045] In this embodiment, the horizontal slide rail 6 is made of POM and has a maximum stroke of 87mm, allowing the sample stage 7 to slide freely on the horizontal slide rail 6, and the closest distance to the X-ray port of the light guide 14 is 8.37mm.

[0046] Detector 15 employs an X-ray silicon drift detector with a resolution of 125 eV FWHM and a photosensitive area of ​​20 mm². 2 The input power is 5VDC, and the external dimensions are 154.1mm×75mm×28.3mm.

[0047] X-ray tube 13 is an end-window type X-ray tube that uses Ag as the target material. The maximum energy of the emitted X-rays is 50keV, the maximum voltage of the X-ray tube is 50kV, the maximum current is 1mA, the actual operating voltage is 30kV, the current is 300μA, and the maximum power is 50W.

[0048] The two data transmission interfaces 1-5 on the shielding layer 1 are connected to the detector 15 and the high-voltage power supply module 3, respectively, and are used for data transmission and power control by connecting to an external computer.

[0049] Instructions for use of this utility model embodiment:

[0050] When using this device, first connect the main power interface 1-4. After all the equipment, including the X-ray tube 13, cooling fan 8, and detector 15, are powered on, use a laptop with a network cable interface to connect to the two data transmission interfaces 1-5 of the device.

[0051] When using this equipment for the first time, the following precautions should be taken: First, preheat the X-ray tube 13 using the control computer. Adjust the current and voltage to the required values. Connect the controller interface 1-6 of the θ-axis angular displacement slide 11. Check if the electrical control box is functioning correctly. Adjust the θ angle to 0°. Check if the detector 15 is functioning correctly. Do not turn on the high voltage of the X-ray tube 13; only turn on the detector 15 for testing and observe the feedback data. Then, turn on the high voltage of the X-ray tube 13 and the detector 15 for testing. Check if the energy spectrum of the detector 15 shows a continuous spectrum of Ag element characteristic peaks. Next, place the Si block on the sample stage 7, turn on the high voltage of the X-ray tube 13, and the detector 15 for testing. Observe if a continuous spectrum of Si element characteristic peaks appears. Adjust the height of the X-ray tube 13 to be the same level as the sample stage 7. Drop 10 μL of a 100 ppm ferric nitrate solution onto the Si block, evaporate it to dryness, place it on the sample stage, and push it into the equipment. Turn on the high voltage of the X-ray tube 13 and the detector 15 for testing. Adjust the height of the X-ray tube 13 to the optimal position based on the test results. Pull out sample stage 7, remove the Si block, clean it, and set it aside. Adjust the X-ray tube 13 to form a very small angle with sample stage 7. Drop 10 μL of a 1 ppm multi-element mixed solution onto the Si block, evaporate it to dryness, and place it on sample stage 7. Turn on the high voltage of X-ray tube 13 and turn on detector 15 to perform the test. Based on the test results, adjust the angle of sample stage 7.

[0052] For subsequent use, simply pull out the sample stage 7, remove the quartz glass, carefully wipe it with alcohol, then rinse it with deionized water and evaporate it to dryness for later use. Each time a sample is tested, depending on its approximate concentration, if the concentration is low, you can first add 10 μL of silanol as a hydrophobic agent. After evaporation, a thin water-conducting film will form, allowing the added sample to accumulate on the quartz glass as much as possible. Then add 5–10 μL of the sample to be tested, evaporate it at low temperature, place it on the sample stage, push in the equipment, close the inlet baffle 4, open the testing software, adjust to the required voltage (0–50 kV) and current (0–1 mA), adjust the testing time (300–1000 s), and then turn on the X-ray 13 and detector 15 for testing. After the test is completed, pull out the sample stage 7, remove the quartz glass, carefully wipe it with alcohol, then rinse it with deionized water and evaporate it to dryness for later use.

[0053] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for detecting trace heavy metals in soil, plants, water bodies, characterized in that, The application relates to a shielding layer, a control sliding table module, an X-ray total reflection system and a high-voltage power supply module. The X-ray total reflection system comprises a base, an X-ray tube, a light guide and a detector, the base is fixed on the top of the theta-axis angular displacement sliding table, the theta-axis angular displacement sliding table can swing the base, the X-ray tube and the light guide are fixed on the base; the light guide comprises an upper fixed block, a lower fixed block, two single-crystal silicon glasses and two ultra-thin metal tantalum sheets, the lower fixed block is fixed on the base, the upper fixed block is arranged on the top of the lower fixed block and is connected through bolts, the upper fixed block and the lower fixed block are both provided with second grooves, the two second grooves are oppositely arranged, the two single-crystal silicon glasses are respectively fixed in the two second grooves, the two metal tantalum sheets are symmetrically clamped between the two single-crystal silicon glasses, and a long and narrow gap is formed between the two single-crystal silicon glasses and the two metal tantalum sheets for X-ray passing; the detector is arranged directly above the sample table; and the X-ray tube is powered by the high-voltage power supply module.

2. The trace heavy metal detection device of claim 1, wherein, The shielding layer is provided with an air inlet, an air outlet and a total power supply interface connected with a three-path power supply module, the air inlet and the air outlet are provided with cooling fans, and the three-path power supply module respectively supplies power for the high-voltage power supply module, the detector and the cooling fans.

3. The trace heavy metal detection device of claim 1, wherein, A lead rubber isolation layer is arranged in the entrance baffle.

4. The trace heavy metal detection device of claim 3, wherein, The entrance baffle is connected with the shielding layer through a hinge.

5. The trace heavy metal detection device of claim 1, wherein, The theta-axis angular displacement sliding table is controlled by electricity, the shielding layer is provided with a controller interface connected with the theta-axis angular displacement sliding table, and the controller interface is used for real-time control of the size of the theta angle by an external computer terminal.

6. The trace heavy metal detection device of claim 1, wherein, The detector is a silicon drift detector with a resolution of 125 eV FWHM and a sensitive area of 20 mm 2 The input power is 5 VDC.

7. The trace heavy metal detection device of claim 1, wherein, The shielding layer is provided with two data transmission interfaces connected with the detector and the high-voltage power supply module respectively, and an external computer terminal is used for data transmission and power control respectively.

8. The trace heavy metal detection device of claim 5, wherein, The swinging range of the theta-axis angular displacement sliding table is + / -10 degrees, and the minimum swinging angle is 0.05 degrees.

9. The trace heavy metal detection device of claim 1, wherein, The X-ray tube adopts Ag as a target material.

10. The trace heavy metal detection device of claim 1, wherein, The sample table is single-crystal silicon glass, and the surface precision is lambda / 10, wherein lambda is 6332.8 nm.

Images