Solution anode glow discharge atomic emission spectrum device assisted by micro magnetic field

Abstract

The invention relates to the technical field of atomic emission spectrum analysis and detection, in particular to a miniature magnetic field assisted solution anode glow discharge atomic emission spectrum device which comprises a sample injection system, a waste liquid discharge system, an excitation source system, a magnetic field system and an analysis and detection system. The tip of the platinum needle is used as a cathode, and the fountain-shaped convex liquid surface of the overflowing solution of the ceramic tube is used as a discharge anode, so that a liquid discharge system is constructed. The tip of the cathode platinum needle discharges to form point discharge; the ceramic tube has hydrophilicity, so that the overflowed solution can stably flow out, and the discharge stability is enhanced; an external magnetic field can cool a cathode platinum needle and deflect charged particles in the plasma to generate a magnetic confinement effect; the continuity of the test system can be realized through sample introduction of the flow injection sample injector; the surge flask is additionally arranged between the flow injection sampler and the ceramic tube, so that the pulsation of the flow injection sampler can be reduced, and the stability of discharge plasma is improved.

Description

Technical Field

[0001] The invention relates to the technical field of atomic emission spectrum analysis and detection, in particular to a micro-magnetic field assisted solution anode glow discharge atomic emission spectrum device. Background Art

[0002] With the development of science and technology, heavy metal pollution incidents caused by illegal mining and excessive discharge in the heavy metal industry have become frequent, seriously threatening human health and ecological safety. Therefore, real-time monitoring of heavy metals in environmental water bodies is of great significance to ecological safety and human health.

[0003] Currently, commonly used methods for determining heavy metals in water include atomic absorption spectroscopy (AAS), atomic fluorescence spectroscopy (AFS), and inductively coupled plasma-atomic emission spectroscopy / mass spectrometry (ICP-AES / MS). These analytical instruments offer advantages such as high sensitivity, low detection limits, and a wide dynamic range. However, they are bulky, expensive, energy-intensive, and consume large amounts of gas, making them inadequate for on-site detection during emergencies. In recent years, the emergence of novel microplasma excitation sources, such as electrolyte cathode glow discharge (ELCAD), atmospheric pressure glow discharge (APGD), solution cathode glow discharge (SCGD), and solution anodic glow discharge (SAGD), has provided new avenues for the development of portable emission spectrometers due to their compact design, simple operation, low cost, low energy consumption, and zero gas consumption. However, the sensitivity of these microplasma excitation sources for some elements is unsatisfactory. Therefore, various approaches have been used to improve their detection sensitivity, such as the addition of suitable organic substances or surfactants and the use of hydride generation (HG), cold vapor generation (CVG), and photochemical vapor generation (PVG) techniques in the sampling system. Although these devices have excellent performance and a wide detection range, they require inert gas and cooling devices, which makes the instruments expensive and difficult to miniaturize, automate, and integrate. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention provides a miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer. This device requires no gas consumption or cooling. The magnetic field exerts a magnetic confinement effect on the plasma, further enhancing the sensitivity of elemental signal detection. The magnetic field also cools the platinum needle in the discharge cathode.

[0005] In order to achieve the above purpose, the technical solutions provided by this patent are as follows:

[0006] A miniature magnetic field assisted solution anode glow discharge atomic emission spectrometer Figure 1 , characterized by: including a sample injection system, a waste liquid discharge system, an excitation source system, a magnetic field system and an analysis and detection system;

[0007] The injection system includes a sample pool 1, a flow injection injector 3 and a buffer bottle 4; the sample pool 1 is connected to the flow injection injector 3 through a silicone tube 2, the flow injection injector 3 is connected to a ceramic tube 6 in a liquid reservoir 5 through another silicone tube, and the buffer bottle 4 is connected between the flow injection injector 3 and the liquid reservoir 5;

[0008] The waste liquid discharge system includes a liquid reservoir 5 and a waste liquid discharge outlet 8. The liquid reservoir 5 is arranged on the supporting translation platform, and the waste liquid discharge outlet 8 is arranged at the bottom of the liquid reservoir 5. The waste liquid discharge outlet 8 discharges waste liquid through a soft rubber tube.

[0009] The excitation source system includes a DC regulated power supply 14, a platinum needle 9, a graphite carbon tube 7 and a ceramic tube 6. The positive electrode 15 of the DC regulated power supply 14 is connected to the graphite carbon tube 7 through a line after being connected to a series resistor 13. The lower end of the graphite carbon tube 7 is inserted into the liquid reservoir 5. The ceramic tube 6 is inserted into the graphite carbon tube 7. The upper end of the ceramic tube 6 is higher than the graphite carbon tube 7. The solution delivered from the flow injection injector 3 overflows from the upper end of the ceramic tube 6 to form a fountain-shaped convex liquid surface, and the convex liquid surface serves as a liquid discharge anode; the negative electrode 16 of the DC regulated power supply 14 is connected to the platinum needle 9 through a line, and the platinum needle 9 serves as a discharge cathode; a glow discharge plasma 12 is generated between the liquid discharge anode and the discharge cathode;

[0010] The magnetic field system includes an N-pole circular permanent magnet 10 and an S-pole circular permanent magnet 11 with N and S poles facing each other, and a glow discharge plasma 12 is located at the center of the magnetic field with N and S poles facing each other.

[0011] The analysis and detection system includes a lens 17, a fiber optic probe 18, a fiber optic spectrometer 19 and a data processing system 20; a lens 17 is provided on one side of the glow discharge plasma 12, and the lens 17 is fixed on the translation stage, and a fiber optic probe 18 is provided on the other side of the lens 17. The lens 17 focuses the glow discharge plasma 12 into the fiber optic probe 18, and the fiber optic probe 18 is connected to the fiber optic spectrometer 19. The fiber optic spectrometer 19 is used to receive signals from the fiber optic probe 18, and the fiber optic spectrometer 19 outputs the received signals to the data processing system 20 for analysis and detection.

[0012] Preferably, the shape of the upper end of the graphite tube 7 is a cross groove slope, a plane or a conical slope ( Figure 2 ).

[0013] Preferably, the support platform and translation stage have micron-level precision, and both are adjustable three-dimensional translation stages. The position of ceramic tube 6 is adjusted by adjusting the support platform, allowing the distance between platinum needle 9 and the convex surface of the overflowing solution in ceramic tube 6 to be adjustable. Simultaneously, the position of lens 17 is adjusted by adjusting the translation stage, aligning the glow generated by the interaction between platinum needle 9 and the convex surface of the overflowing solution, the center of lens 17, and optical fiber probe 18. This allows the glow discharge plasma to be focused by lens 17 and then enter optical fiber probe 18.

[0014] Preferably, the diameter of the lens 17 is 5-13 cm.

[0015] Preferably, the outer diameter of the graphite carbon tube 7 is 3-5 mm, the depth of the lower end of the graphite carbon tube 7 inserted into the liquid reservoir is 1-2 cm, the inner diameter of the ceramic tube 6 is 1-2 mm, and the diameter of the platinum needle 9 is 0.8-1.3 mm.

[0016] Preferably, the liquid storage tank 5 is a cylindrical glass container with a diameter of 2-3 cm and a height of 4-5 cm.

[0017] Preferably, the N-pole circular permanent magnet 10 and the S-pole circular permanent magnet 11 are placed on a supporting platform, and the diameter of the N-pole circular permanent magnet 10 and the S-pole circular permanent magnet 11 is 18-30 mm, and the thickness is 5-10 mm.

[0018] The beneficial effects of the present invention are:

[0019] 1. This invention constructs a liquid discharge system using the tip of a platinum needle as the cathode and the fountain-like convex surface of the overflowing solution from a ceramic tube as the discharge anode. Platinum is used as the cathode electrode material because it is an inert metal and is not easily corroded. Discharge from the tip of the platinum needle creates a sharp discharge, resulting in low power consumption, high excitation efficiency, and high sensitivity. The use of a ceramic tube is primarily due to the ceramic's hydrophilicity, which allows for smooth outflow of the overflowing solution and enhances discharge stability.

[0020] 2. The present invention introduces a magnetic field unit within the glow region, which increases the sensitivity of detected elements and expands the detection range through magnetic confinement. Furthermore, the magnetic field cools the platinum needle. Therefore, the system requires no cooling device, no additional gas environment, and no sample introduction components such as an atomizer, facilitating miniaturization.

[0021] 3. The automatic switching function of the flow injection injector of the present invention can complete continuous injection and realize the automation of the system; adding a buffer bottle between the flow injection injector and the ceramic tube can eliminate the instability of the solution caused by the pulsation of the peristaltic pump in the flow injection injector, thereby obtaining a more stable glow discharge plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural schematic diagram of a miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer provided by the present invention; in the figure: 1 is a sample cell, 2 is a first silicone tube, 3 is a flow injection injector, 4 is a buffer bottle, 5 is a liquid storage tank, 6 is a ceramic tube, 7 is a graphite carbon tube, 8 is a waste liquid outlet, 9 is a platinum needle, 10 is an N-pole circular permanent magnet, 11 is an S-pole circular permanent magnet, 12 is a glow discharge plasma, 13 is a resistor, 14 is a DC regulated power supply, 15 is the positive electrode of the power supply, 16 is the negative electrode of the power supply, 17 is a lens, 18 is a fiber optic probe, 19 is a fiber optic spectrometer, and 20 is a data processing system;

[0023] Figure 2 These are photos of the graphite carbon tubes provided in Examples 1, 2 and 3 of the present invention when the upper ends thereof have different shapes.

[0024] Figure 3 1 is the relationship between the Tl signal intensity of graphite carbon tubes of different shapes provided in Examples 1, 2 and 3 of the present invention (a is the cross groove slope, b is the plane, and c is the tapered slope).

[0025] Figure 4 Photographs of glow discharge plasma taken when the upper end of the graphite carbon tube provided in Example 3 of the present invention is a conical slope, where (a) is a 0T magnetic field and (b) is a 0.55T magnetic field.

[0026] Figure 5 This is a full spectrum of the glow discharge emission spectrum provided in Example 3 of the present invention, wherein (a) is a 0T magnetic field; (b) is a 0.55T magnetic field.

[0027] Figure 6 This is the relationship between the Tl signal intensity of the coexisting ion pair provided in Example 3 of the present invention, wherein the discharge gap is 1.3 mm, the solution flow rate is 3.0 mL / min, the discharge voltage is 550 V, and the pH is 1.6.

[0028] Figure 7 This is the relationship between the signal intensity at Tl 377.8 nm and time provided in Example 3 of the present invention, wherein the discharge gap is 1.3 mm, the solution flow rate is 3.0 mL / min, the discharge voltage is 550 V, and the pH is 1.6.

[0029] Figure 8 Example 3 of the present invention provides the relationship between signal intensity and Tl concentration at 0T and 0.55T magnetic field strengths, wherein the discharge gap is 1.3mm, the solution flow rate is 3.0mL / min, the discharge voltage is 550V, and the pH is 1.6. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0031] A miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer ( Figure 1 ), characterized in that it includes a sample injection system, a waste liquid discharge system, an excitation source system, a magnetic field system and an analysis and detection system;

[0032] The injection system includes a sample pool 1, a buffer bottle 4 and a flow injection injector 3; the sample pool 1 is connected to the flow injection injector 3 through a first silicone tube 2, the flow injection injector 3 is connected to a ceramic tube 6 in a liquid reservoir 5 through another silicone tube, and the buffer bottle 4 is connected between the flow injection injector 3 and the liquid reservoir 5;

[0033] The waste liquid discharge system includes a liquid reservoir 5 and a waste liquid discharge outlet 8. The liquid reservoir 5 is arranged on the supporting translation platform, and the waste liquid discharge outlet 8 is arranged at the lower part of the liquid reservoir 5. The waste liquid discharge outlet 8 discharges waste liquid through a soft rubber tube.

[0034] The excitation source system includes a DC regulated power supply 14, a platinum needle 9, a graphite carbon tube 7 and a ceramic tube 6. The positive electrode 15 of the DC regulated power supply 14 is connected to the graphite carbon tube 7 through a line after being connected to a series resistor 13. The lower end of the graphite carbon tube 7 is inserted into the liquid reservoir 5. The ceramic tube 6 is inserted into the graphite carbon tube 7. The upper end of the ceramic tube 6 is higher than the graphite carbon tube 7. The solution delivered from the flow injection injector 3 overflows from the upper end of the ceramic tube 6 to form a fountain-shaped convex liquid surface, and the convex liquid surface serves as a liquid discharge anode; the negative electrode 16 of the DC regulated power supply 14 is connected to the platinum needle 9 through a line, and the platinum needle 9 serves as a discharge cathode; a glow discharge plasma 12 is generated between the liquid discharge anode and the discharge cathode;

[0035] The magnetic field system includes an N-pole circular permanent magnet 10 and an S-pole circular permanent magnet 11 with N and S poles facing each other, and a glow discharge plasma 12 is located at the center of the magnetic field with N and S poles facing each other.

[0036] The analysis and detection system includes a lens 17, a fiber optic probe 18, a fiber optic spectrometer 19 and a data processing system 20; a lens 17 is provided on one side of the glow discharge plasma 12, and the lens 17 is fixed on the translation stage, and a fiber optic probe 18 is provided on the other side of the lens 17. The lens 17 focuses the glow discharge plasma 12 into the fiber optic probe 18, and the fiber optic probe 18 is connected to the fiber optic spectrometer 19. The fiber optic spectrometer 19 is used to receive signals from the fiber optic probe 18, and the fiber optic spectrometer 19 outputs the received signals to the data processing system 20 for analysis and detection.

[0037] Preferably, the shape of the upper end of the graphite carbon tube 7 is a cross groove slope, a plane or a conical slope ( Figure 2 ).

[0038] Preferably, the precision of the support platform and the translation stage is in the micron level, and both the support platform and the translation stage adopt an adjustable three-dimensional translation stage; the position of the ceramic tube 6 is adjusted by adjusting the support platform, so that the distance between the platinum needle 9 and the fountain-shaped convex liquid surface of the overflowing solution of the ceramic tube 6 can be adjusted. At the same time, the position of the lens 17 is adjusted by adjusting the translation stage, so that the glow generated by the interaction between the platinum needle 19 and the convex liquid surface of the overflowing liquid, the center of the lens 17 and the optical fiber probe 18 are in a straight line, so that the glow discharge plasma is focused by the lens 17 and enters the optical fiber probe 18.

[0039] Preferably, the diameter of the lens 17 is 5-13 cm.

[0040] Preferably, the diameter of the graphite carbon tube 7 is 3-5 mm, the depth of the lower end of the graphite carbon tube 7 inserted into the liquid reservoir is 1-2 cm, the inner diameter of the ceramic tube 6 is 1-2 mm, and the diameter of the platinum needle 9 is 0.8-1.3 mm.

[0041] Preferably, the liquid storage tank 5 is a cylindrical glass container with a diameter of 2-3 cm and a height of 4-5 cm.

[0042] Preferably, the N-pole circular permanent magnet 10 and the S-pole circular permanent magnet 11 are placed on a supporting platform, and the diameter of the N-pole circular permanent magnet 10 and the S-pole circular permanent magnet 11 is 18-30 mm, and the thickness is 5-10 mm.

[0043] Example 1

[0044] The DC regulated power supply used was an LW100J2, providing a voltage of 0-1000V and a current of 0-500mA. A 1-5kΩ shunt resistor was connected in series between the graphite carbon tube and the positive terminal of the DC regulated power supply. The diameter of the platinum needle was 0.8-1.3mm, the distance between the upper end of the ceramic tube and the upper end of the graphite carbon tube was 3-6mm, the outer diameter of the graphite carbon tube was 3-5mm, and the lower end of the graphite carbon tube was inserted into the liquid reservoir to a depth of 1-2cm. The volume of the liquid reservoir was 125-500mL.

[0045] The N and S poles of the circular magnet are 1-2 cm apart, and the glow discharge plasma is located at the center of the magnetic field where the N and S poles face each other. The liquid reservoir, platinum needle, and circular magnet all utilize a support platform. Both the support platform and translation stage are adjustable three-dimensional translation stages with micron-level precision, allowing for adjustable distances between the platinum needle and the overflow convex surface of the ceramic tube, as well as between the circular magnet and the glow plasma.

[0046] Open the flow injection injector, 3 mg L -1 The Tl standard solution was injected into the sampler at a rate of 3 mL min -1 The liquid enters the buffer bottle and flows into the ceramic tube at a flow rate of 100 nm. The overflow liquid in the ceramic tube flows into the liquid storage tank along the outer wall of the graphite carbon tube.

[0047] The anode is a graphite carbon tube (5 cm long and 1.5 mm in diameter) Figure 2 In the ceramic tube a), the upper end of the graphite carbon tube is 7 mm away from the upper end of the ceramic tube. The upper end of the graphite carbon tube has a cross-grooved slope. The cathode is a platinum needle, and the anode and cathode are 2 mm apart. When the discharge voltage applied between the two electrodes increases to 550-600 V, the current is 11-15 mA, and the external resistance is 2 kΩ, the solution around the anode platinum needle is broken down, generating a stable glow and forming a stable glow discharge plasma.

[0048] During the discharge process, a circular magnet is added to create a magnetic confinement effect on the plasma, making it more stable. The plasma then passes through a lens into a fiber optic probe, which transmits the signal to a spectrometer. Finally, a data processing system analyzes the optical signal, completing the qualitative or quantitative detection of the Tl element in the solution. By analyzing the element's characteristic spectrum, the composition and concentration of the metal element in the substance being tested can be determined, enabling online detection of metal elements in solution.

[0049] Example 2

[0050] The DC regulated power supply used was an LW100J2, providing a voltage of 0-1000V and a current of 0-500mA. A 1-5kΩ shunt resistor was connected in series between the graphite rod and the positive terminal of the DC regulated power supply. The diameter of the platinum needle was 0.8-1.3mm, the distance between the upper end of the ceramic tube and the upper end of the graphite carbon tube was 3-6mm, the diameter of the graphite carbon tube was 3-5mm, and the lower end of the graphite carbon tube was inserted into the liquid reservoir to a depth of 1-2cm. The volume of the liquid reservoir was 125-500mL.

[0051] The N and N poles of the circular magnet are 1-2 cm apart, and the glow discharge plasma is located at the center of the magnetic field where the N and N poles face each other. The liquid reservoir, platinum needle, and circular magnet all utilize a support platform. Both the support platform and translation stage are adjustable three-dimensional translation stages with micron-level precision, allowing for adjustable distances between the platinum needle and the overflow surface of the ceramic tube, as well as between the circular magnet and the glow plasma.

[0052] Open the flow injection injector, 3 mg L -1 The Tl standard solution was injected into the sampler at a rate of 3 mL min -1 The liquid flows into the ceramic tube through the buffer bottle at a flow rate, and the overflow liquid in the ceramic tube flows into the liquid storage tank along the outer wall of the graphite carbon tube.

[0053] The anode is a 5 cm long, 1.5 mm diameter embedded graphite carbon tube ( Figure 2 b) In the ceramic tube, the upper end of the graphite carbon tube is 7 mm from the upper end of the ceramic tube. The upper end of the graphite carbon tube is flat. The cathode is a platinum needle. The anode and cathode are 2 mm apart. When the discharge voltage applied between the two electrodes increases to 550-600 V, the current is 11-15 mA, and the external resistance is 2 kΩ, the electrolyte surrounding the anode platinum needle breaks down, generating a stable glow and forming a stable glow discharge plasma.

[0054] During the discharge process, a circular magnet is added to create a magnetic confinement effect on the plasma, making it more stable. The plasma then passes through a lens into a fiber optic probe, which transmits the signal to a spectrometer. Finally, a data processing system analyzes the optical signal, completing the qualitative or quantitative detection of the Tl element in the solution. By analyzing the element's characteristic spectrum, the composition and concentration of the metal element in the substance being tested can be determined, enabling the detection of metal elements in solution.

[0055] Example 3

[0056] The DC regulated power supply uses LW100J2 DC regulated power supply, providing voltage 0-1000V and current 0-500mA. Figure 2c) A 1-5 kΩ shunt resistor is connected in series with the positive terminal of the DC regulated power supply. The diameter of the platinum needle is 0.8-1.3 mm, the distance between the upper end of the ceramic tube and the upper end of the graphite carbon tube is 3-6 mm, the diameter of the graphite carbon tube is 3-5 mm, the depth of the lower end of the graphite carbon tube inserted into the liquid reservoir is 1-2 cm, and the volume of the liquid reservoir is 125-500 mL.

[0057] The N and S poles of the circular magnet are 1-2 cm apart, and the glow discharge plasma is at the center of the magnetic field where the N and S poles are opposite. The liquid reservoir, platinum needle, and circular magnet all use a support platform. The support platform and translation stage are both adjustable three-dimensional translation stages with micron-level accuracy, so that the distance between the platinum needle and the overflow liquid surface of the ceramic tube can be adjusted, and the distance between the circular magnet and the glow plasma can be adjusted.

[0058] Open the flow injection injector, 3 mg L -1 The Tl standard solution was injected into the sampler at a rate of 3 mL min -1 The liquid flows into the ceramic tube through the buffer bottle at a flow rate, and the overflow liquid in the ceramic tube flows into the liquid storage tank along the outer wall of the graphite carbon tube.

[0059] The anode is a 5 cm long, 1.5 mm diameter ceramic tube embedded with a graphite carbon tube. The upper end of the graphite carbon tube is 7 mm from the upper end of the ceramic tube, and the upper end of the graphite carbon tube is inclined. The cathode is a platinum needle, with the cathode and anode 2 mm apart. When the discharge voltage applied between the two electrodes is increased to 550-600 V, the current is 11-15 mA, and the external resistance is 2 kΩ, the electrolyte surrounding the anode platinum needle breaks down, generating a stable glow and forming a stable glow discharge plasma. During the discharge process, the addition of a circular magnet creates a magnetic confinement effect on the plasma, which further stabilizes the discharge plasma. The plasma then passes through a lens into a fiber optic probe, which transmits the signal to a spectrometer. Finally, a data processing system analyzes the optical signal to complete the qualitative or quantitative detection of the Tl element in the solution. By analyzing the characteristic spectrum of the element, the composition and concentration of the metal element in the substance being tested can be obtained, thus enabling the detection of metal elements in solution.

[0060] Figure 3 Figure 3 shows the changes in emission spectrum signal intensity under different graphite tube morphologies. It can be seen that the emission intensity is highest when the upper end of the graphite carbon tube is an inclined surface, and the emission signal intensity of the Tl element is lowest when the upper end of the graphite carbon tube is a flat surface, which proves that the performance is best when the upper end of the graphite carbon tube is an inclined surface. Figure 4The figures show discharge images of glow plasma taken by an ICCD camera under magnetic fields of 0T (a) and 0.55T (b). Comparing the two images, it can be seen that after the magnetic field is applied, the volume of the plasma decreases, resulting in an increase in the electron density in this area, indicating that the introduction of the magnetic field produces a magnetic confinement effect on the plasma region. A large number of high-energy electrons in the plasma are affected by the Lorentz force, which causes their movement paths to change, and then they are pinched and confined within the effective field, increasing the collision frequency of the plasma and thus improving the excitation efficiency of the elements.

[0061] Figure 5 The emission spectra with and without magnetic field are shown. In the emission spectra, there is OH (A 2 Σ + →X 2 The spectrum of П,309.0-315.8nm) is generated because the high-energy electrons (energy greater than 10eV) in the plasma bombard the gaseous water molecules, causing the water molecules to be excited, ionized and decomposed into OH. Since the discharge is carried out in an air environment, the molecular band spectrum of N2 (C 3 Пu→B 3 П g ,337-391.4nm). At the same time, due to the Tl dissolved in the solution + After the ions enter the plasma region, they are atomized and the atomic emission line of Tl (377.8nm) is observed. However, after the magnetic field is introduced ( Figure 2 b) The emission intensity of Tl increases, indicating that the magnetic field significantly enhances the excitation of Tl. The above information shows that magnetic field-assisted solution anodic glow discharge can be used to detect Tl in solution.

[0062] Figure 6 K is the recovery rate of Tl interference in the presence of coexisting ions. + , Ca 2+ 、Na + Mg 2+ 、Cu 2+ 、Mn 2+ 、Fe 3+ , Pb 2+ 、Zn 2+ 、SO4 2- 、Cl - Plasma was used as interfering ions. The results showed that most interfering ions had a greater interference on Tl element when there was no magnetic field. After adding a magnetic field, the recovery rate increased and the interference decreased. Figure 7 The relative standard deviation is 3.8 when there is no magnetic field, and it is 2.3 when the magnetic field is added, indicating that the stability of the plasma increases after the magnetic field is added. Figure 8Figure 2 is the standard curve of Tl element with and without magnetic field. It can be seen from the figure that the standard curves obtained with and without magnetic field have a good linear relationship.

[0063] Table 1 shows the relevant parameters of Tl after linear fitting under 0T and 0.55T magnetic field conditions. It can be seen that the correlation coefficient R 2 are all greater than 0.99, indicating that they have good linear relationships; the detection limits of Tl in the absence of a magnetic field are 6.6 μg L -1 However, the detection limit of Tl decreased to 2.1 μg L under 0.55T magnetic field. -1 After adding the magnetic field, the sensitivity increased by 2.2 times, the detection limit decreased by 3.1 times, and the energy consumption decreased from 3.2-15W to 2.7-13.4W, indicating that the magnetic field-assisted solution anode glow discharge atomic emission spectrometry device has the advantages of low power consumption, high sensitivity, and low detection limit.

[0064] Table 1 Analytical performance and indicators for determination of Tl

[0065]

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer, characterized by: Including sampling system, waste liquid discharge system, excitation source system, magnetic field system and analysis and detection system; The injection system comprises a sample pool (1) and a buffer bottle (4), wherein the sample pool (1) is connected to a flow injection injector (3) via a silicone tube (2), the flow injection injector (3) is connected to a ceramic tube (6) in a liquid reservoir (5) via another silicone tube, and the buffer bottle (4) is connected between the flow injection injector (3) and the liquid reservoir (5); The waste liquid discharge system comprises a liquid reservoir (5), the liquid reservoir (5) being arranged on a supporting translation platform, a waste liquid discharge outlet (8) being arranged at the lower portion of the liquid reservoir (5), and the waste liquid discharge outlet (8) discharges the waste liquid in the liquid reservoir (5) through a soft rubber hose; The excitation source system comprises a DC regulated power supply (14), a platinum needle (9), a graphite carbon tube (7) and a ceramic tube (6); the positive electrode (15) of the DC regulated power supply (14) is connected to the graphite carbon tube (7) via a line after being connected to a series resistor (13); the lower end of the graphite carbon tube (7) is inserted into a liquid storage tank (5); a ceramic tube (6) is provided inside the graphite carbon tube (7); the upper end of the ceramic tube (6) is higher than the graphite carbon tube (7); the solution transported from the flow injection injector (3) overflows from the upper end of the ceramic tube (6) to form a fountain-shaped convex liquid surface, and the convex liquid surface serves as a liquid discharge anode; the negative electrode (16) of the DC regulated power supply (14) is connected to the platinum needle (9) via a line, and the platinum needle (9) serves as a discharge cathode; a glow discharge plasma (12) is generated between the liquid discharge anode and the discharge cathode; The magnetic field system comprises an N-pole circular permanent magnet (10) and an S-pole circular permanent magnet (11) with N-pole opposite to each other, and the glow discharge plasma (12) is located at the magnetic field center of the N-pole; The analysis and detection system comprises a lens (17), an optical fiber probe (18), an optical fiber spectrometer (19) and a data processing system (20); a lens (17) is provided on one side of the glow discharge plasma (12), the lens (17) is fixed on a translation stage, and an optical fiber probe (18) is provided on the other side of the lens (17); the lens (17) focuses the glow discharge plasma (12) into the optical fiber probe (18), the optical fiber probe (18) is connected to the optical fiber spectrometer (19), the optical fiber spectrometer (19) is used to receive signals from the optical fiber probe (18), and the optical fiber spectrometer (19) outputs the received signals to the data processing system (20) for analysis and detection.

2. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The shape of the upper end of the graphite carbon tube (7) is a cross groove slope, a plane or a conical slope.

3. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The support platform and the translation stage have a precision of micron level, and both the support platform and the translation stage adopt an adjustable three-dimensional translation stage. The position of the ceramic tube (6) is adjusted by adjusting the support platform, so that the distance between the platinum needle (9) and the convex liquid surface of the ceramic tube (6) is adjustable. At the same time, the position of the lens (17) is adjusted by adjusting the translation stage, so that the glow generated by the interaction between the platinum needle (9) and the convex liquid surface, the center of the lens (17) and the optical fiber probe (18) are on the same straight line, so that the glow discharge plasma (12) enters the optical fiber probe (18) after being focused by the lens (17).

4. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The diameter of the lens (17) is 5-13 cm.

5. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The outer diameter of the graphite carbon tube (7) is 3-5 mm, the depth of the lower end of the graphite carbon tube (7) inserted into the liquid storage tank is 1-2 cm, the inner diameter of the ceramic tube (6) is 1-2 mm, and the diameter of the platinum needle (9) is 0.8-1.3 mm.

6. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The liquid storage tank (5) is a cylindrical glass container with a diameter of 2-3 cm and a height of 4-5 cm.

7. The miniature magnetic field-assisted solution anode glow discharge atomic emission spectrometer according to claim 1, characterized in that: The N-pole circular permanent magnet (10) and the S-pole circular permanent magnet (11) are placed on a supporting platform. The diameter of the N-pole circular permanent magnet (10) and the S-pole circular permanent magnet (11) are 18-30 mm, and the thickness is 5-10 mm.

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