Detection method and device for inductively coupled plasma mass spectrometry

Abstract

The invention belongs to the technical field of element detection equipment, and particularly relates to a detection method and device for inductively coupled plasma mass spectrometry, the device comprises a mass spectrometer body and a sampling mechanism, the sampling mechanism is mounted on the mass spectrometer body, and the sampling mechanism is used for extracting a sample solution; according to the invention, the sampling mechanism is improved, a sealed cleaning and soaking space is provided for the sampling tube by utilizing the lifting motion of the sample tube in cooperation with the sealing plug and the lifting groove in the taking interval of multiple test solutions, and pure water for cleaning enters and exits from the water storage tank through the change of the volume of the cleaning space, so that the automatic cleaning of the sampling tube is realized; in the taking process of different solutions, especially solutions with large viscosity, the phenomenon that various solutions are mixed can be effectively avoided, and especially when the solutions in the sample tube are not completely taken, the residual solutions in the sample tube can be effectively prevented from being polluted.

Description

Technical Field

[0001] The present invention belongs to the technical field of element detection equipment, and specifically relates to a detection method and device for inductively coupled plasma mass spectrometry. Background Art

[0002] Inductively coupled plasma mass spectrometry is a new analytical and testing technology developed in the 1980s of the 20th century. It combines the high-temperature (7000K) ionization characteristics of ICP with the advantages of sensitive and fast scanning of a quadrupole mass spectrometer through a unique interface technology, thus forming a new type of element / isotope analysis technology. And the plasma mass spectrometer is one of the instruments applying inductively coupled plasma mass spectrometry.

[0003] When testing aqueous sediments, soils, basic rocks or ultrabasic rocks by using plasma mass spectrometry, it is necessary to configure the sample into a sample solution, then insert the sampling catheter into the solution for sampling. After sampling, the solution sample is sent into the plasma light source through an atomizer, vaporized at high temperature, dissociated into ionized gas, the ions collected by a copper or nickel sampling cone form a molecular beam under a low vacuum of about 133.322 Pa, and then enter the quadrupole mass analyzer through an extraction plate with a diameter of 1 - 2 mm. After mass separation by a mass filter, it reaches the ion detector. According to the proportional relationship between the count of the detector and the concentration, the content of the element or the isotope ratio can be measured. Since intermittent sampling is required during sampling so that the particles on the display board impact to form an intermittent sample pattern, it is necessary for the staff to manually control the insertion and extraction of the sampling hose. At the same time, during the multi-concentration detection process, the staff also needs to manually switch different sample solutions. Meanwhile, the staff also needs to operate the control program of the equipment, thus making the sampling operation rather troublesome.

[0004] A related technology discloses a sample introduction device for an inductively coupled plasma mass spectrometer, with the application number CN2021107145139. In this scheme, the driving wheel device controls the driven wheel device to perform intermittent reciprocating motion, so that the slide plate device on the side controls the sampling device to achieve cyclic intermittent control of in-out-in sampling; at the same time, the cylinder installed on the top of the sampling device cooperates with the piston to achieve the effect of quantitative sampling. However, it is found in the actual application process that although the feeding operation is intermittent due to the movement of the slide plate device, because there are many types of solutions to be used during the actual sampling process, when switching the sampling solution, the sampling equipment is inserted into the solution, which easily causes the mixing of the solutions in the container, resulting in the scrapping of the solution after sampling, and does not conform to the experimental concept of energy conservation and environmental protection.

[0005] In view of this, the present invention proposes a detection method and device for inductively coupled plasma mass spectrometry to solve the above technical problems. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art and solve the above technical problems, the present invention proposes a detection method and device for inductively coupled plasma mass spectrometry.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows: A detection device for inductively coupled plasma mass spectrometry according to the present invention includes a mass spectrometer body and a sampling mechanism. The sampling mechanism is installed on the mass spectrometer body, and the sampling mechanism is used to extract a sample solution.

[0008] The sampling mechanism includes:

[0009] A sample disk, which is rotatably installed on the mass spectrometer body. The sample disk is equipped with evenly distributed sample tubes, and the sample disk is externally connected to a switching motor.

[0010] A sampling tube. A lifting groove is formed on the mass spectrometer body, and the sampling tube is slidably installed in the lifting groove.

[0011] An electric push rod, which is fixedly installed on the mass spectrometer body. The output end of the electric push rod extends into the lifting groove, and the electric push rod is used to push the sampling tube up and down.

[0012] A piston, which is slidably installed in the lifting groove. The sampling tube is fixedly installed below the piston.

[0013] A plunger. A drainage groove is formed in the piston. A one-way valve is installed in the drainage groove. The drainage groove is unidirectionally communicated with the sampling tube through the one-way valve. A plunger is installed in the drainage groove, and the output end of the electric push rod is fixedly connected to the plunger.

[0014] A sealing plug, which is fixedly installed at the bottom opening of the lifting groove. A tapered hole is formed in the sealing plug. The tapered hole is closed in the initial state and is matched with the sampling tube.

[0015] An injection tube, which extends into the lifting groove. When the piston is at the lowest position in the lifting groove, the drainage groove is aligned and communicated with the injection tube, and the injection tube is unidirectionally conductive.

[0016] A water storage tank and a cleaning tube. The water storage tank is installed on the mass spectrometer body, and the cleaning tube is installed on the water storage tank. The cleaning tube extends into the lifting groove.

[0017] Preferably, an elastic sheet is fixedly installed on the plunger, and the edge of the elastic sheet extends and is fixed on the upper surface of the piston.

[0018] Preferably, the cleaning pipe is composed of a liquid inlet pipe and a liquid outlet pipe. The liquid inlet pipe is fixedly installed on the piston, and the liquid outlet pipe is fixedly installed on the sealing plug. A permeable membrane plate is installed in the water storage tank. The liquid inlet pipe and the liquid outlet pipe are respectively located on both sides of the permeable membrane plate, and both the liquid inlet pipe and the liquid outlet pipe are one-way conduction pipes.

[0019] Preferably, a drainage ring is fixedly installed on the piston. The drainage ring is coaxially arranged with the sampling pipe and the lifting groove. The liquid inlet pipe is open above the drainage ring, and the drainage ring is used to guide the liquid flow to flow on the inner wall of the lifting groove and the outer wall of the sampling pipe.

[0020] Preferably, a switching groove is opened at the connection between the lifting groove and the sampling pipe. A switching plate is slidably installed in the switching groove. A first conduction valve and a second conduction valve are installed on the switching plate. Both the first conduction valve and the second conduction valve are one-way conduction, and the conduction directions are opposite. The switching plate is designed in a C shape.

[0021] Preferably, a three-way valve is fixedly installed at one end of the sampling pipe away from the lifting groove. A return pipe is installed on the three-way valve. The return pipe extends into the lifting groove, and when the piston is at the top end of the lifting groove, the return pipe is aligned and conducted with the drainage groove.

[0022] Preferably, a valve plate is hingedly installed in the three-way valve. A tension spring is fixedly installed at one end of the three-way valve facing the return pipe. In the initial state, the valve plate blocks the return pipe.

[0023] Preferably, the top end of the switching groove is designed in an H shape, and the opening of the switching groove is misaligned with the return pipe. When the piston pushes the switching plate to move to the top end of the switching groove, the drainage groove is aligned with the return pipe.

[0024] Preferably, a friction plate is fixedly installed on the switching plate, and the friction between the friction plate and the switching groove is greater than the gravity of the switching plate.

[0025] A detection method for inductively coupled plasma mass spectrometry, the method comprising the following steps:

[0026] S1. Preparation of standard working solution: The standard stock solution is serially diluted to 100 ug / l with 10% nitric acid solution and prepared freshly for use.

[0027] S2. Preparation of standard solution: Select suitable standard curve concentration points, transfer the standard working solution into the same group of 100 ml volumetric flasks, and dilute and make up the volume with 10% nitric acid solution.

[0028] S3. Preparation of sample: Take no less than 500 g of a representative sample that has been fully mixed. After the sample is air-dried, ground and sieved, it is mixed well and placed in a sealed container for storage at room temperature for later use.

[0029] S4. Preparation of sample solution: weigh the sample and mix it with nitric acid, perchloric acid and hydrofluoric acid in a polytetrafluoroethylene crucible and heat until evaporated to dryness, then mix it with aqua regia after cooling and heat to dissolve;

[0030] S5, reagent blank solution: prepare a blank solution without sample according to the above steps;

[0031] S6. Mass spectrometry detection: The sample solution, blank solution and other solutions are introduced into the sample tube in sequence, and the elements in the sample solution are detected by inductively coupled plasma mass spectrometry.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. The detection method and device for inductively coupled plasma mass spectrometry described in the present invention improve the sampling mechanism. In the interval of taking multiple test solutions, the lifting and lowering movement of the sample tube is utilized, and the sealing plug and the lifting groove are cooperated to provide a sealed cleaning and soaking space for the sampling tube. The volume of the cleaning space changes, so that the pure water for cleaning enters and exits the water storage tank, thereby realizing automatic cleaning of the sampling tube. In the process of taking different kinds of solutions, especially those with high viscosity, the phenomenon of mixing between multiple solutions can be effectively avoided. In particular, when the solution in the sample tube is not completely taken, the remaining solution in the sample tube can be effectively prevented from being contaminated.

[0034] 2. The detection method and device for inductively coupled plasma mass spectrometry described in the present invention changes the conduction direction of the sampling tube, so that during the lifting and lowering of the sampling tube and the piston, the sampling tube is always disconnected from the lifting groove, so that the flow path of pure water is relatively stable, which can not only prevent pure water from entering the sampling tube and affecting the solution taken, but also enable the pure water to stably flush the sampling tube, thereby enhancing the cleaning effect of the sampling tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] Figure 1 is a stereogram of the present invention;

[0037] Figure 2 It is a partial structural stereogram of the present invention;

[0038] Figure 3 It is a stereoscopic diagram of the assembly of the electric push rod, plunger and piston;

[0039] Figure 4 It is a stereogram of the switchboard;

[0040] Figure 5 is a transverse cross-sectional view of the present invention;

[0041] Figure 6 yesFigure 5 Partial enlarged view at location A in

[0042] Figure 7 is Figure 5 Partial enlarged view at location B in

[0043] Figure 8 is the method flowchart of the present invention;

[0044] In the figure: 1, mass spectrometer body; 11, sample tray; 12, sample tube; 13, switching motor; 2, sampling tube; 21, lifting groove; 22, electric push rod; 23, piston; 24, drainage groove; 25, plunger; 26, sealing plug; 27, injection tube; 28, elastic sheet; 3, water storage tank; 31, liquid inlet tube; 32, liquid outlet tube; 33, osmotic membrane plate; 4, drainage ring; 41, switching groove; 42, switching plate; 43, first conduction valve; 44, second conduction valve; 5, three-way valve; 51, return pipe; 52, valve plate; 53, tension spring; 54, friction plate. Detailed implementation manner

[0045] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.

[0046] As Figures 1 to 8 shown, a detection device for inductively coupled plasma mass spectrometry according to the present invention includes a mass spectrometer body 1 and a sampling mechanism, the sampling mechanism is installed on the mass spectrometer body 1, and the sampling mechanism is used for extracting a sample solution;

[0047] The sampling mechanism includes:

[0048] A sample tray 11, the sample tray 11 is rotatably installed on the mass spectrometer body 1, uniformly distributed sample tubes 12 are installed on the sample tray 11, and the sample tray 11 is externally connected to a switching motor 13;

[0049] A sampling tube 2, a lifting groove 21 is provided on the mass spectrometer body 1, and the sampling tube 2 is slidably installed in the lifting groove 21;

[0050] An electric push rod 22, the electric push rod 22 is fixedly installed on the mass spectrometer body 1, the output end of the electric push rod 22 extends into the lifting groove 21, and the electric push rod 22 is used for pushing the sampling tube 2 to move up and down;

[0051] A piston 23, the piston 23 is slidably installed in the lifting groove 21, and the sampling tube 2 is fixedly installed below the piston 23;

[0052] The plunger 25 is arranged inside the piston 23, and a drainage groove 24 is formed inside the piston 23. A one-way valve is installed in the drainage groove 24. The drainage groove 24 is in one-way communication with the sampling tube 2 through the one-way valve. A plunger 25 is installed in the drainage groove 24. The output end of the electric push rod 22 is fixedly connected to the plunger 25;

[0053] The sealing plug 26 is fixedly installed at the bottom opening of the lifting groove 21. A tapered hole is formed in the sealing plug 26. The tapered hole is closed in the initial state and is matched with the sampling tube 2;

[0054] The sampling tube 27 extends into the lifting groove 21. When the piston 23 is at the lowest position in the lifting groove 21, the drainage groove 24 is aligned and communicated with the sampling tube 27, and the sampling tube 27 is in one-way communication;

[0055] The water storage tank 3 and the cleaning tube. The water storage tank 3 is installed on the mass spectrometer body 1, the cleaning tube is installed on the water storage tank 3, and the cleaning tube extends into the lifting groove 21.

[0056] An elastic sheet 28 is fixedly installed on the plunger 25. The edge of the elastic sheet 28 extends and is fixed on the upper surface of the piston 23. The presence of the elastic sheet 28 can block the gap between the plunger 25 and the drainage groove 24 and enhance the sealing performance of the drainage groove 24.

[0057] When using an inductively coupled plasma mass spectrometer to sample the prepared sample solution, in order to enhance the automation and convenience of the sampling operation, and at the same time to prevent the mixing of various test solutions during the sampling process, the sampling mechanism in the present invention is improved to meet the above requirements.

[0058] Specifically, in the present invention, the sampling mechanism is installed on the mass spectrometer body 1. The inlet pipe 27 is directly connected to the atomization mechanism inside the mass spectrometer body 1 and is used to supply the test solution to the atomization mechanism. The sampling pipe 2 is used to extract the test solution placed in the sample tube 12. After the staff prepares the test solution, the test solution is filled into the sample tube 12 one by one in the extraction order. Under the control of the set program, the switching motor 13 cooperates with the sample tray 11. During the rotation process, the sample tube 12 is successively moved below the sampling pipe 2. At the same time, under the control of the program, the output end of the electric push rod 22 extends. Since the output end of the electric push rod 22 is directly connected to the plunger 25, and the plunger 25 is installed in the drainage groove 24 on the piston 23. When the plunger 25 moves downward, the plunger 25 first slides downward in the drainage groove 24, and then pushes the piston 23 downward, thereby causing the sampling pipe 2 to gradually descend in the lifting groove 21. During the descent of the sampling pipe 2, its bottom end first contacts the sealing plug 26, and then extends through the conical groove opened on the sealing plug 26. In the present invention, the sealing plug 26 is made of elastic rubber material. Therefore, during the relative movement between the sampling pipe 2 and the sealing plug 26, they are always in a sliding seal connection state. When the elongation of the electric push rod 22 reaches the preset value, at this time, the sampling pipe 2 is inserted into the solution in the sample tube 12, and the opening of the drainage groove 24 on the piston 23 is aligned and conducted with the inlet pipe 27. At this time, the electric push rod 22 performs a short-distance reciprocating motion, and the reciprocating motion distance is less than the depth of the drainage groove 24. When the electric push rod 22 drives the plunger 25 to perform a reciprocating motion, since the drainage groove 24 and the sampling pipe 2 are unidirectionally conducted by a one-way plug, under the action of negative pressure, the solution in the sample tube 12 is promoted to flow into the drainage groove 24 and flows from the drainage groove 24 into the inlet pipe 27, thereby realizing the extraction and pumping. During the solution extraction and pumping process, according to the preset program, the start and stop of the electric push rod 22 are controlled to make the solution pumping intermittent, so as to facilitate the formation of intermittent sample patterns by particle impact on the display board. When a certain solution is used up, at this time, under the control of the program, the electric push rod 22 contracts, pulling the plunger 25, the piston 23 and the sampling pipe 2 to rise and reset. During this process, since the inlet pipe 27 is unidirectionally conducted and the conduction direction is away from the lifting groove 21, the part of the lifting groove 21 below the piston 23 presents a negative pressure state. Under the action of negative pressure, the pure water in the water storage tank 3 is extracted into the lifting groove 21 through the cleaning pipe, thereby flushing the inner wall of the lifting groove 21 and the sampling pipe 2 gradually extending into the lifting groove 21. When the sample tray 11 moves, the electric push rod 22 pushes the sampling pipe 2 to descend again. At this time, the cleaning water in the lifting groove 21 flows back to the water storage tank 3, and the soaked sampling pipe 2 descends to a new sample tube 12 again, thereby extracting the solution in the sample tube 12.

[0059] The present invention improves the sampling mechanism. In the interval of taking multiple test solutions, the lifting movement of the sample tube 12 is utilized, and the sealing plug 26 and the lifting groove 21 are cooperated to provide a sealed cleaning and soaking space for the sampling tube 2. The volume of the cleaning space changes, so that the pure water for cleaning enters and exits the water storage tank 3, thereby realizing automatic cleaning of the sampling tube 2. In the process of taking different kinds of solutions, especially those with high viscosity, the phenomenon of mixing between multiple solutions can be effectively avoided. In particular, when the solution in the sample tube 12 is not completely taken, the remaining solution in the sample tube 12 can be effectively prevented from being contaminated.

[0060] As a preferred embodiment of the present invention, the cleaning pipe is composed of a liquid inlet pipe 31 and a liquid outlet pipe 32, the liquid inlet pipe 31 is fixedly installed on the piston 23, and the liquid outlet pipe 32 is fixedly installed on the sealing plug 26. A permeable membrane plate 33 is installed in the water storage tank 3, and the liquid inlet pipe 31 and the liquid outlet pipe 32 are respectively located on both sides of the permeable membrane plate 33, and the liquid inlet pipe 31 and the liquid outlet pipe 32 are both unidirectional guide pipes.

[0061] In order to reduce the amount of cleaning water used during frequent use, the cleaning pipe in the present invention is composed of a liquid inlet pipe 31 and a liquid outlet pipe 32, and the liquid inlet pipe 31 and the liquid outlet pipe 32 are both one-way conducting pipes. When the piston 23 and the sampling tube 2 move upward in the lifting tank 21, under the action of negative pressure, the liquid inlet pipe 31 extracts pure water from the liquid outlet pipe 32, and the pure water enters the lifting tank 21 to clean the sampling tube 2. Then, when the piston 23 and the sampling tube 2 descend again, under the action of gravity and pressure, the pure water in the liquid inlet pipe 31 is drawn out of the liquid outlet pipe 32, and the pure water enters the lifting tank 21 to clean the sampling tube 2. Next, the pure water in the lifting tank 21 enters the water storage tank 3 through the liquid outlet pipe 32. Since a permeable membrane plate 33 is installed in the water storage tank 3, and the liquid inlet pipe 31 and the liquid outlet pipe 32 are respectively located on both sides of the permeable membrane plate 33, the pure water circulates during multiple cleaning processes, and is filtered through the permeable membrane plate 33 during the flow process. In other embodiments of the present application, the liquid outlet pipe 32 can also be directly connected to the wastewater discharge channel, and the cleaning water can be directly discharged to enhance the cleaning effect on the sampling tube 2.

[0062] As a preferred embodiment of the present invention, a drainage ring 4 is fixedly installed on the piston 23, and the drainage ring 4 is coaxially arranged with the sampling tube 2 and the lifting groove 21. The liquid inlet pipe 31 is opened above the drainage ring 4, and the drainage ring 4 is used to guide the liquid to flow toward the inner wall of the lifting groove 21 and the outer wall of the sampling tube 2.

[0063] During the rising process of the piston 23, pure water is drawn into the liquid inlet pipe 31 under the action of negative pressure and flows out from the liquid inlet pipe 31. The outflowing pure water is guided to the inner wall of the lifting groove 21 and the outer wall of the sampling tube 2 respectively under the action of gravity and the drainage ring 4, and then the continuous flushing of pure water is used to enhance the cleaning effect of the outer wall of the sampling tube 2.

[0064] It should be noted that when the drainage ring 4 is designed, the clearance widths between its two sides and the inner wall of the lifting groove 21 and the outer wall of the sampling tube 2 are less than 2 mm. When pure water flows from the liquid inlet pipe 31 to the upper surface of the drainage ring 4, the smaller the clearance between the drainage ring 4 and the inner wall of the lifting groove 21 and the outer wall of the sampling tube 2, the more effectively the pure water can flow along the inner wall of the lifting groove 21 and the outer wall of the sampling tube 2 in a wall-attached manner.

[0065] As a preferred embodiment of the present invention, a switching groove 41 is provided at the connection between the lifting groove 21 and the sampling pipe 27. A switching plate 42 is slidably installed in the switching groove 41. A first on-off valve 43 and a second on-off valve 44 are installed on the switching plate 42. Both the first on-off valve 43 and the second on-off valve 44 are unidirectional conduction, and the conduction directions are opposite. The switching plate 42 is designed in a C shape.

[0066] A friction plate 54 is fixedly installed on the switching plate 42. The friction between the friction plate 54 and the switching groove 41 is greater than the gravity of the switching plate 42. The existence of the friction force can effectively prevent the switching plate 42 from moving by itself when it is not pushed by the piston 23.

[0067] During the upward movement of the piston 23, negative pressure is used to extract pure water for cleaning. When the piston 23 descends, pressure and gravity are used to promote the discharged pure water after cleaning to be discharged through the liquid outlet pipe 32. In order to further reduce the probability of pure water entering the sampling pipe 27, a switching groove 41 is provided in the present invention. A switching plate 42 is slidably installed in the switching groove 41. During the downward movement of the piston 23, as the piston 23 gradually descends, the piston 23 pushes the switching plate 42 to descend, so that the sampling pipe 27 is conducted with the first on-off valve 43. The conduction direction of the first on-off valve 43 faces the sampling pipe 27. Therefore, the solution pumped in the drainage groove 24 is pumped into the sampling pipe 2 through the first on-off valve 43. Then, when the piston 23 and the sampling pipe 2 rise, a negative pressure state exists in the lower part of the lifting pipe at this time. The existence of the negative pressure causes the first on-off valve 43 to close, which is convenient for pure water in the water storage tank 3 to enter the lifting groove 21. When the piston 23 continues to rise, due to the C-shaped design of the switching plate 42, the piston 23 pushes the switching plate 42 again, causing the switching plate 42 to rise. At this time, the second on-off valve 44 is aligned with the sampling pipe 27, and the conduction directions of the second on-off valve 44 and the first on-off valve 43 are opposite. Therefore, under the hydraulic action of the pure water in the lifting groove 21, the second on-off valve 44 closes. When the piston 23 descends again, the purified water can only be discharged through the liquid outlet pipe 32.

[0068] During the entire cleaning process, by changing the conduction direction of the sampling tube 2, it is ensured that during the up and down movement of the sampling tube 2 and the piston 23, the sampling tube 2 is always non-conductive with the lifting groove 21, making the flow path of pure water relatively stable. This can not only prevent pure water from entering the sampling tube 2 and affecting the solution to be taken, but also enable the pure water to stably flush the sampling tube 2, enhancing the cleaning effect on the sampling tube 2.

[0069] As a preferred embodiment of the present invention, a three-way valve 5 is fixedly installed at one end of the sampling tube 27 away from the lifting groove 21. A return pipe 51 is installed on the three-way valve 5, and the return pipe 51 extends into the lifting groove 21. When the piston 23 is at the top of the lifting groove 21, the return pipe 51 is aligned and conductive with the drainage groove 24.

[0070] A valve plate 52 is hingedly installed inside the three-way valve 5. A tension spring 53 is fixedly installed at one end of the three-way valve 5 facing the return pipe 51. In the initial state, the valve plate 52 blocks the return pipe 51.

[0071] Since the solution enters the atomization mechanism through the sampling tube 27, liquid will also remain in the sampling tube 27. To reduce the mixing between the solutions to be taken and affect the detection results, when the piston 23 and the sampling tube 2 rise and reset, at this time the sampling tube 2 is completely located in the lifting groove 21. The pure water for cleaning extracted from the lifting groove 21 enters the inside of the sampling tube 2 through the bottom opening of the sampling tube 2. At this time, the electric push rod 22 performs a small up and down movement again under the control of a pre-set program, causing the plunger 25 to move back and forth in the drainage groove 24, thereby forming a negative pressure in the drainage groove 24, prompting the pure water in the lifting groove 21 to enter the drainage groove 24 from the inside of the sampling tube 2 and enter the return pipe 51 from the drainage groove 24. As the hydraulic pressure in the return pipe 51 gradually increases, the water flow pushes the valve plate 52 to deflect, thereby making the return pipe 51 conductive with the sampling tube 27, and the sampling tube 27 is separated from the atomization mechanism. Under the action of gravity and the driving force of the water flow, the pure water enters the sampling tube 27 and the lifting groove 21 from the return pipe 51, and then cooperates with the plunger 25 to continuously move back and forth in the drainage groove 24, thereby making the water flow form a cycle. During the water flow cycle, the sampling tube 27, the sampling tube 2, and the drainage groove 24 are flushed, further reducing the probability of mixing between various liquids when taken, and improving the detection accuracy of the liquid.

[0072] The top of the switching groove 41 is designed in an H shape, and the switching groove 41 is misaligned with the opening of the return pipe 51. When the piston 23 pushes the switching plate 42 to move to the top of the switching groove 41, the drainage groove 24 is aligned with the return pipe 51.

[0073] The top of the switching groove 41 is set in an H shape, which can avoid the return pipe 51 during the up and down movement of the switching plate 42.

[0074] As a preferred embodiment of the present invention, the purpose of this method is to provide a method for detecting silver, aluminum, arsenic, barium, beryllium, bismuth, calcium, cadmium, cerium, cobalt, chromium, cesium, copper, dysprosium, erbium, europium, iron, gadolinium, holmium, indium, potassium, lanthanum, lithium, lutetium, magnesium, manganese, molybdenum, sodium, niobium, neodymium, nickel, phosphorus, lead, praseodymium, antimony, scandium, samarium, tin, strontium, tantalum, terbium, thorium, titanium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, and zinc in water system sediments, soils, basic rocks, and ultrabasic rocks by inductively coupled plasma mass spectrometry.

[0075] To achieve the above purpose, this method adopts the following technical solutions:

[0076] Reagents and materials:

[0077] Unless otherwise specified, all reagents used in this method are of analytical reagent grade. The experimental water meets the requirements of Grade 1 water specified in GB / T 6682;

[0078] Hydrofluoric acid solution (analytical reagent grade);

[0079] Perchloric acid solution (analytical reagent grade);

[0080] Nitric acid solution (analytical reagent grade);

[0081] Hydrochloric acid solution (analytical reagent grade);

[0082] 1% nitric acid solution: Pipette 10 ml of nitric acid solution and dilute it to 1000 ml with deionized water;

[0083] Standard stock solution: Purchase commercially available certified standard solutions;

[0084] Standard working solution: Gradually dilute the standard stock solution with 1% nitric acid solution and prepare it freshly before use;

[0085] Online internal standard solution: Purchase commercially available certified RH standard solution and prepare a solution with a concentration of 10 μg / ml with 1% nitric acid;

[0086] Mass spectrometry tuning solution: The tuning solution is provided by the instrument itself.

[0087] Instruments and equipment:

[0088] Note: The containers used should be boiled with dilute nitric acid before use.

[0089] Inductively coupled plasma mass spectrometer (ICP-MS);

[0090] Analytical balance: The weighing accuracy is up to 0.0001 g;

[0091] Ultra-pure water system;

[0092] 25 ml polytetrafluoroethylene crucible;

[0093] Laboratory sample crusher;

[0094] Preparation of test sample:

[0095] Take no less than 500 g of representative samples that have been fully mixed evenly. After the samples are air-dried, ground, and sieved, mix them evenly and put them into a sealed container for storage at room temperature for later use.

[0096] Detection steps:

[0097] Preparation of standard working solution: Gradually dilute the standard stock solution with 10% nitric acid solution to 100 μg / L, and prepare it immediately before use.

[0098] Preparation of standard solution: Select appropriate concentration points for the standard curve, transfer a certain volume of the standard working solution into a group of 100 ml volumetric flasks, dilute it to the mark with 10% nitric acid solution, and mix well.

[0099] Preparation of sample solution: Take no less than 500 g of representative samples that have been fully mixed evenly. After the samples are air-dried, ground, and sieved, mix them evenly and put them into a sealed container for storage at room temperature for later use. Weigh 0.1000 g (accurate to 0.0001 g) of the sample into a 25 ml polytetrafluoroethylene crucible, moisten it with a little water, then add 5 ml of nitric acid, 1 ml of perchloric acid, and 10 ml of hydrofluoric acid. Heat it on a graphite temperature-controlled electric hot plate (temperature controlled at 220 °C) in a fume hood to drive off the acid until it is evaporated to dryness. After taking it down and cooling, add 5 ml of aqua regia, place it on the graphite temperature-controlled electric hot plate until the sample is completely dissolved and the solution is clear. Take it down, cool slightly, then transfer it to a 50 ml volumetric flask, dilute it to the mark with pure water, mix well, and let it stand for measurement. Prepare the reagent blank solution according to the method of the above steps.

[0100] Mass spectrometry interference and correction: In ICP-MS measurement, the main mass spectrometry interferences include isobaric interference, refractory oxide interference, polyatomic complex ion interference, and double-charged ion interference, etc. Among them, the superposition of mass spectrometry peaks and polyatomic complex ion interference are relatively serious. The mass spectrometer has two modes: ordinary mode and helium collision mode. The helium collision mode can remove most of the polyatomic complex ion interferences. The present invention adopts the helium collision mode. For the superposition of mass spectrometry peaks, select appropriate concentration points for the standard curve, transfer a certain volume of the standard working solution of the interfering element into a group of 50 ml volumetric flasks, dilute it to the mark with 10% nitric acid solution, mix well, and after the instrument is preheated and stabilized, rinse it with ultrapure water until the signal reaches the lowest, and then measure the value of the interfered element.

[0101] The present invention uses the dual detector mode and adds the AMS argon dilution function, so that even if the intensity of some elements is relatively large, accurate testing can still be carried out. For the detection of trace elements, when the detection limit of the instrument is sufficient, increase the dilution factor to make the solid solubility of the sample less than 0.2%. The detection limit mainly depends on the test requirements of the sample, usually between 3 - 10 ng / g.

[0102] Selection of elements for isotope determination: Selecting measurement isotopes of elements with less interference and complex interference mechanisms can effectively reduce some mass spectrometry interferences.

[0103] Select Rh102.9 as the internal standard, and correct the interference formula for the elements to be determined. Then measure the standard solutions of each concentration in sequence. Taking the average value of three measurements as the ordinate and the concentration as the abscissa, plot the standard curve; introduce the dissolved sample solution into the inductively coupled plasma mass spectrometry for measurement, take the average value of three measurements, calculate the corresponding concentration from the standard curve, subtract the concentration of the corresponding blank solution, and calculate the content of the element.

[0104] Analysis steps:

[0105] 1. Digestion:

[0106] Preparation of sample solution: Take no less than 500 g of a representative sample that has been thoroughly mixed. After the sample is air-dried, ground, and sieved, mix it well and transfer it into a sealed container for storage at room temperature for later use. Weigh 0.1000 g (accurate to 0.0001 g) of the sample into a 25 ml polytetrafluoroethylene crucible, moisten it with a little water, then add 5 ml of nitric acid, 1 ml of perchloric acid, and 10 ml of hydrofluoric acid. Heat it on a graphite temperature-controlled electric hot plate (temperature controlled at 220 °C) in the fume hood to drive off the acid until it is evaporated to dryness. After taking it down and cooling, add 5 ml of aqua regia, place it on the graphite temperature-controlled electric hot plate until the sample is completely dissolved and the solution is clear. Then take it down, let it cool slightly, transfer it to a 50 ml volumetric flask, dilute it to the mark with pure water, mix it well, and let it stand for measurement.

[0107] Reagent blank solution: Prepare the blank solution according to the method of the above steps.

[0108] 2. Instrument reference conditions

[0109] Power: 1500 kw;

[0110] Carrier gas flow rate: 0.84 L / min;

[0111] Helium gas flow rate: 0.48 L / min;

[0112] AMS gas flow rate: 0.2 L / min;

[0113] 3. Standard curve plotting

[0114] Preparation of standard solution: Select appropriate concentration points for the standard curve. Pipette a certain volume of the standard stock solution into the same set of 100 ml volumetric flasks, dilute it to the mark with 10% nitric acid solution, and mix it well. Add the internal standard online and detect the samples with increasing concentration. Calculate the standard regression equation based on the signal count - concentration.

[0115] 4. Measurement

[0116] After igniting the plasma, the instrument is preheated and stabilized for 30 minutes. The sensitivity, oxides, and double charges of the instrument are tuned with a mass spectrometer tuning solution. The double-detector mode is calibrated with the tuning solution to meet the test requirements. The sample solution is introduced into the inductively coupled plasma mass spectrometer, and the internal standard is added online. The interference formula is filled in the interference element column to obtain the signal counts of each element to be measured and the internal standard element. According to the intensity ratio of each element to be measured and the internal standard element, the signal counts of each element to be measured after correction are obtained, and the concentration mass of each element is obtained by looking up the standard curve.

[0117] Blank experiment: Conduct duplicate blank experiments. Except for not adding samples, parallel determinations are carried out using exactly the same determination steps.

[0118] The advantages of this method are as follows: 1. Generally, the existing methods use microwave digestion, which takes a long time and has certain risks. This method is simple and fast, requires simple equipment, and is suitable for the determination of multiple elements in a large number of samples.

[0119] 2. Simultaneous determination of major, minor, and rare earth elements is achieved by a single sample dissolution and determination, reducing the use of other instruments and improving the analysis efficiency.

[0120] 3. Through interference correction, the determination of low contents of some elements is achieved, meeting the requirements of the "Quality Control Specifications for Geological and Mineral Laboratory Tests" DZ / T 0130.4 - 2006 for the element detection limit.

[0121] 4. The sample digestion equipment of this method is simple and the cost is low.

[0122] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A detection device for inductively coupled plasma mass spectrometry, comprising a mass spectrometer body (1) and a sampling mechanism, wherein the sampling mechanism is installed on the mass spectrometer body (1), and the sampling mechanism is used for extracting a sample solution; It is characterized in that: The sampling mechanism includes: A sample disk (11), the sample disk (11) is rotatably installed on the mass spectrometer body (1), uniformly distributed sample tubes (12) are installed on the sample disk (11), and the sample disk (11) is externally connected to a switching motor (13); A sampling tube (2), a lifting groove (21) is opened on the mass spectrometer body (1), and the sampling tube (2) is slidably installed in the lifting groove (21); An electric push rod (22), the electric push rod (22) is fixedly installed on the mass spectrometer body (1), the output end of the electric push rod (22) extends into the lifting groove (21), and the electric push rod (22) is used for pushing the sampling tube (2) to move up and down; A piston (23), the piston (23) is slidably installed in the lifting groove (21), and the sampling tube (2) is fixedly installed below the piston (23); A plunger (25), a drainage groove (24) is opened in the piston (23), a one-way valve is installed in the drainage groove (24), the drainage groove (24) is unidirectionally conducted with the sampling tube (2) through the one-way valve, a plunger (25) is installed in the drainage groove (24), and the output end of the electric push rod (22) is fixedly connected to the plunger (25); A sealing plug (26), the sealing plug (26) is fixedly installed at the bottom opening of the lifting groove (21), a tapered hole is opened on the sealing plug (26), the tapered hole is closed in the initial state, and the tapered hole is matched with the sampling tube (2); An injection tube (27), the injection tube (27) extends into the lifting groove (21), when the piston (23) is located at the bottommost of the lifting groove (21), the drainage groove (24) is aligned and conducted with the injection tube (27), and the injection tube (27) is unidirectionally conducted; A water storage tank (3) and a cleaning tube, the water storage tank (3) is installed on the mass spectrometer body (1), the cleaning tube is installed on the water storage tank (3), and the cleaning tube extends into the lifting groove (21).

2. The detection device for inductively coupled plasma mass spectrometry according to claim 1, wherein: An elastic sheet (28) is fixedly installed on the plunger (25), and the edge of the elastic sheet (28) extends and is fixed on the upper surface of the piston (23).

3. The detection device for inductively coupled plasma mass spectrometry according to claim 2, characterized in that: The cleaning tube is composed of a liquid inlet tube (31) and a liquid outlet tube (32), the liquid inlet tube (31) is fixedly installed on the piston (23), the liquid outlet tube (32) is fixedly installed on the sealing plug (26), a permeable membrane plate (33) is installed in the water storage tank (3), the liquid inlet tube (31) and the liquid outlet tube (32) are respectively located on both sides of the permeable membrane plate (33), and the liquid inlet tube (31) and the liquid outlet tube (32) are both one-way conduction tubes.

4. The detection device for inductively coupled plasma mass spectrometry according to claim 3, wherein: A drainage ring (4) is fixedly installed on the piston (23). The drainage ring (4) is coaxially arranged with the sampling tube (2) and the lifting groove (21). The liquid inlet pipe (31) is arranged with an opening above the drainage ring (4). The drainage ring (4) is used to guide the liquid flow to flow on the inner wall of the lifting groove (21) and the outer wall of the sampling tube (2).

5. The detection device for inductively coupled plasma mass spectrometry according to claim 4, characterized in that: A switching groove (41) is opened at the conduction part between the lifting groove (21) and the sampling pipe (27). A switching plate (42) is slidably installed in the switching groove (41). A first conduction valve (43) and a second conduction valve (44) are installed on the switching plate (42). Both the first conduction valve (43) and the second conduction valve (44) conduct unidirectionally, and the conduction directions are opposite. The switching plate (42) is designed in a C shape.

6. The detection device for inductively coupled plasma mass spectrometry according to claim 5, characterized in that: One end of the sampling pipe (27) far from the lifting groove (21) is fixedly installed with a three-way valve (5). A return pipe (51) is installed on the three-way valve (5). The return pipe (51) extends into the lifting groove (21). When the piston (23) is located at the top of the lifting groove (21), the return pipe (51) is aligned and conducted with the drainage groove (24).

7. The detection device for inductively coupled plasma mass spectrometry according to claim 6, characterized in that: A valve piece (52) is hingedly installed in the three-way valve (5). One end of the three-way valve (5) facing the return pipe (51) is fixedly installed with a tension spring (53). In the initial state, the valve piece (52) blocks the return pipe (51).

8. The detection device for inductively coupled plasma mass spectrometry according to claim 7, wherein: The top of the switching groove (41) is designed in an H shape. The switching groove (41) is misaligned with the opening of the return pipe (51). When the piston (23) pushes the switching plate (42) to move to the top of the switching groove (41), the drainage groove (24) is aligned with the return pipe (51).

9. The detection device for inductively coupled plasma mass spectrometry according to claim 8, characterized in that: A friction plate (54) is fixedly installed on the switching plate (42). The friction between the friction plate (54) and the switching groove (41) is greater than the gravity of the switching plate (42).

10. A detection method for inductively coupled plasma mass spectrometry, characterized in that: This method uses a detection device for inductively coupled plasma mass spectrometry described in claim 9. This method includes the following steps: S1. Preparation of standard working solution: Gradually dilute the standard stock solution with 10% nitric acid solution to 100 ug / l, and prepare it for use immediately as needed. S2. Preparation of standard solution: Select suitable standard curve concentration points, transfer the standard working solution into the same group of 100 ml volumetric flasks, and dilute and make up the volume with 10% nitric acid solution. S3. Preparation of sample: Take no less than 500 g of a representative sample that has been fully mixed. After the sample is air-dried, ground and sieved, mix it evenly and put it into a sealed container for storage at room temperature for standby. S4. Preparation of sample solution: Weigh the sample and mix it with nitric acid, perchloric acid and hydrofluoric acid in a polytetrafluoroethylene crucible and heat it to dryness. After cooling, mix it with aqua regia and heat it to dissolve. S5. Reagent blank solution: Prepare a blank solution without sample according to the method of the above steps. S6. Mass spectrometry detection: Introduce solutions such as the sample solution and the blank solution into the sample tube (12) in sequence, and use inductively coupled plasma mass spectrometry to detect the elements in the sample solution.

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