CN108844927A - A kind of sample introduction system and its Atomic Fluorescence Spectrometer - Google Patents

Abstract

The invention provides a sample introduction system and an atomic fluorescence spectrometer thereof, which mainly include introduction, detection, control and gas path systems. The introduction system includes an inner electrode, an outer electrode and a reactor with a cavity, the reactor has a product outlet and a waste outlet connected to the cavity, and a carrier gas inlet is directly or indirectly connected to the cavity. communication, a sampling system communicates with the cavity and its nozzle protrudes into the cavity, one end of the internal electrode protrudes into the cavity and faces the nozzle, and the other end passes through the reactor The external electrode is connected to the external electrode through an AC power supply, and the external electrode is facing the end of the internal electrode extending into the cavity, and covers the outer wall of the nozzle or the outer wall of the reactor. The sample solution ejected from the nozzle collides with the inner electrode. Beneficial effects: the structure is simple, the operation is convenient, the analysis speed is fast, the analysis cost is low, the analysis efficiency is high, and the detection accuracy of each element can be ensured.

Description

A sample introduction system and its atomic fluorescence spectrometer

technical field

The invention relates to the technical field of analytical chemistry atomic spectrum analysis, in particular to a sample introduction system and an atomic fluorescence spectrometer thereof.

Background technique

Sample introduction technology has always been a key issue in analytical chemistry, especially for the analysis of trace and ultra-trace elements in complex matrix samples. The efficiency of sample introduction significantly affects the analytical properties of an analytical method, such as sensitivity, precision, and robustness.

Common sampling methods include pneumatic atomization, steam generation and electrothermal evaporation techniques. The pneumatic atomization sampling method has the advantages of simplicity, rapidity and good stability, but its sample introduction efficiency is low (<5%), and it is seriously interfered by the matrix. The vapor generation injection method significantly improves sample introduction efficiency (nearly 100%) and reduces matrix interference. However, it is severely interfered by transition metal elements (especially Ni, Co and Cu), and its sampling efficiency depends on the chemical form of the analyzed elements. In addition, the reducing agent Na/KBH ₄ used is expensive and unstable. The electrothermal evaporation sampling technology has the advantages of high sample introduction efficiency, less sample volume and direct analysis of liquid and solid samples, but it consumes a lot of power and has poor reproducibility (>10% RSD).

Recently, dielectric barrier discharge micro-plasma is used as an atomization source and a desorption ion source, such as the Chinese patent CN200910061663.3 titled mercury vapor generation method and device, which records: the cathode and anode of the DC power supply are sealed in the discharge device , a capillary is inserted upwardly into the discharge device from the lower end of the discharge device, and an electrolyte solution is first introduced to the bottom of the discharge device through the capillary, and the electrolyte solution becomes a part of the cathode because the cathode of the discharge device is connected , and then introduce the mercury-containing sample into the discharge device through the capillary. Since both the sample to be tested and the electrolyte solution are brought in through the capillary, the residue of the electrolyte solution on the capillary is likely to affect the subsequent detection results of the sample to be tested, and the sample to be tested that is sprayed upward from the capillary The droplet is relatively large, and when the large droplet enters the atomizer in the subsequent detection device, it will have a greater impact on the atomizer, which will reduce the stability of the signal.

Chinese patent CN201010520352.1 titled Mercury Form Analysis Method and Mercury Vapor Generator Based on Liquid Cathode Discharge states that the cathode and anode of the DC power supply are sealed in the discharge battery, and a capillary is inserted upward from the lower end of the discharge battery In the described discharge cell, at first import the mercury-containing sample to the bottom of the described discharge cell through the described capillary, and this mercury-containing sample also serves as the discharge cathode at the same time, but when the sample to be tested is used as the discharge cathode, the reaction that occurs in the plasma region is Oxidation reactions cannot induce mercury to realize vapor generation, so it is mainly the bombardment of positive charges on the liquid surface that causes mercury vapor generation. In addition, a large amount of water vapor will be generated when the positive charge bombards the liquid surface. When the formed large droplets enter the atomizer in the subsequent device, the detection of the atomizer and the fluorescence signal will be greatly affected, and the stability of the signal will be reduced.

In the Chinese patent CN201110414527.5 titled a method for generating atomic vapor based on dielectric barrier discharge, the atomic vapor generation device based on dielectric barrier discharge in the technical solution uses a micro-syringe to inject samples. Due to the plasma generated by dielectric barrier discharge It belongs to low-temperature plasma, so when using injection sampling, it is necessary to introduce the sample into the plasma area, which will increase the risk of electric shock; The temperature of the body and the injection speed are related, so the use of injection injection increases the instability of the signal, which will greatly reduce the stability of the method and the accuracy of the test results; finally, the interference of coexisting ions in this method is large, and it is difficult to Enables analysis of complex samples.

The technical scheme described in the Chinese patent CN201110207416.7, titled dielectric barrier discharge micro-plasma-induced evaporation sampling method, takes samples by dipping. On the one hand, repeated dipping of samples is cumbersome to operate; It is difficult to ensure that the sample taken by dipping is consistent every time, which reduces the stability of the method; finally, the applicable elements of this method are limited, only mercury.

Contents of the invention

In view of this, an embodiment of the present invention provides a sample introduction system and its atomic fluorescence spectrometer to overcome the above problems.

An embodiment of the present invention provides a sample introduction system based on dielectric barrier discharge induced vapor generation, comprising an inner electrode, an outer electrode, and a reactor with a cavity, and the reactor is provided with a product outlet communicating with the cavity and a waste discharge port, a carrier gas inlet communicates directly or indirectly with the cavity, a sampling system communicates with the cavity and its nozzle extends into the cavity, and one end of the inner electrode extends into the cavity The cavity is facing the nozzle, and the other end passes through the reactor and is connected to the external electrode through an AC power supply. The external electrode is facing the end of the internal electrode extending into the cavity, and covered The outer wall of the nozzle or the outer wall covering the reactor, the sample solution sprayed out by the nozzle will collide with the inner electrode when falling down.

Further, the sampling system is a nebulizer, which includes a plugged sampling hose at one end, a large vent tube with the nozzle at the other end, and an inlet connecting the sampling hose to the nozzle. The sample capillary, the carrier gas inlet is arranged in the large ventilation tube, the carrier gas flows between the large vent tube and the sample injection capillary and enters the cavity through the nozzle, and the sample solution It is located in the thin sampling tube and forms an aerosol when sprayed out by the nozzle.

Further, the outer electrode is a conductor electroplated on the outer wall of the nozzle or a conductive sheet wrapped around the outer wall of the nozzle or a conductive wire wound on the outer wall of the nozzle; the inside of the inner electrode is filled with conductive material, The outside is an insulating dielectric barrier layer, and the conductive material is connected to the external electrode through the AC power supply.

Further, the dielectric barrier layer is a hollow structure made of glass, quartz or ceramics, the conductive material filled inside is a saturated electrolyte solution or conductive glue, and the dielectric barrier layer is placed horizontally with the nozzle perpendicular to each other, the hollow structure includes a hollow sphere in the cavity and a hollow cylinder connected to the hollow sphere and partly protrudes out of the cavity, and the sampling system is located at the top of the reactor , the aerosol ejected by the nozzle collides with the hollow sphere when falling down.

Further, the product outlet is located below the internal electrode and higher than the waste discharge port, and the waste discharge port is located at the bottom of the reactor.

Further, the sampling system is located at the upper end of the reactor, which is a sampling tube with its nozzle facing downwards, and the external electrode is a conductor electroplated on the outer wall of the reactor or is wrapped around the outer wall of the reactor. A conductive sheet or a conductive wire wound on the outer wall of the reactor, the inside of the inner electrode is filled with a conductive material, and the outside is an insulating dielectric barrier layer, and the conductive material and the outer electrode are connected through the AC power supply , the inner electrode is arranged vertically, and its upper end is sealed, and the upper end of the inner electrode passes through the surrounding of the outer electrode and faces the nozzle.

Further, the nozzle is a horn-shaped structure facing downwards, and the maximum diameter of the horn-shaped structure is greater than or equal to the diameter of the inner electrode. When the sample solution falls from the horn structure to the surface of the dielectric barrier layer, it will A liquid film is formed on the surface of the dielectric barrier layer.

Further, the product outlet communicates with the reactor, is located above the outer electrode, and extends out of the upper end area surrounded by the outer electrode facing the inner electrode, and the carrier gas inlet is located on the outer electrode. Below, and on the side opposite to the product outlet, the waste outlet is located at the lower end region of the reactor, lower than the height of the carrier gas inlet.

Further, the carrier gas is an inert gas or a mixed gas of an inert gas and hydrogen or a mixed inert gas.

An embodiment of the present invention provides an atomic fluorescence spectrometer based on dielectric barrier discharge-induced vapor generation, including the above-mentioned sample introduction system based on dielectric barrier discharge-induced vapor generation, and also includes a detection system, a control system, and a gas circuit system. The detection system It is equipped with an atomizer, a hollow cathode light source surrounding the atomizer to excite fluorescent signals, a photomultiplier tube for converting fluorescent signals into electrical signals, and a signal processing unit connected to the photomultiplier tube device, the control system is provided with a control module and a display, the gas circuit system includes a hydrogen source and an argon source, and three ports of a tee are respectively connected with the product outlet of the sample introduction system, the atomizer The hydrogen source is communicated with the hydrogen source through a pipeline, the argon source is communicated with the carrier gas inlet of the sample introduction system and the atomizer, and the hydrogen source is directly communicated with the carrier gas inlet of the sample introduction system through a pipeline , the control module is connected with the gas circuit system and the detection system to control the output of the gas circuit system and the amount of hydrogen and argon, and to control the work of each component of the detection system, and the display is used for It displays the output hydrogen and argon volumes of the gas path system, and displays the working status of each component of the detection system and the processing results of the signal processor.

The beneficial effects brought by the technical solutions provided by the embodiments of the present invention are: (1) when using the sample introduction system and atomic fluorescence spectrometer thereof according to the present invention, no additional chemical reduction reagents need to be added, which saves chemical reagents and reduces Potential pollution caused by chemical reagents; (2) has the advantages of high vapor generation efficiency, strong tolerance to coexisting ions, and can realize the vapor generation of various elements; (3) replaces the hydrogenation in traditional atomic fluorescence spectrometers Vapor generation sampling system improves the sampling efficiency and reduces the volume of the atomic fluorescence spectrometer. The power consumption of the sample introduction system of the present invention is lower than 25W; (4) simple in structure and easy to operate. The advanced sample introduction system and its atomic fluorescence spectrometer can shorten the analysis time, reduce the analysis cost, improve the analysis efficiency, and can ensure the accuracy and reliability of the detection of each element.

Description of drawings

Fig. 1 is the schematic diagram of embodiment 1 of the sample introduction system based on the dielectric barrier discharge induced vapor generation of the present invention;

Fig. 2 is the schematic diagram of embodiment 2 of the sample introduction system based on the dielectric barrier discharge-induced vapor generation of the present invention;

3 is a schematic diagram of Embodiment 3 of the sample introduction system based on dielectric barrier discharge-induced vapor generation of the present invention;

Fig. 4 is that the present invention measures the fluorescent signal figure of blank and lead standard sample;

Fig. 5 is that the present invention measures the fluorescent signal figure of blank and cadmium standard sample;

6 is a schematic diagram of the structure and composition of the atomic fluorescence spectrometer based on dielectric barrier discharge-induced vapor generation in the present invention;

Fig. 7 is a schematic diagram of the internal structure composition of the detection system in the atomic fluorescence spectrometer based on dielectric barrier discharge induced vapor generation of the present invention.

The labels in the figure are: 6, 17-sampling system; 7-sampling thin tube; 8, 24, 30-carrier gas inlet; 9, 26, 34-AC power supply; 10, 22, 31-internal electrode; 11 , 20 - reactor; 12, 18, 27 - product outlet; 13, 21 - waste outlet; 14 - hollow sphere; 15, 23 - dielectric barrier; 16, 19, 28 - external electrode; 29 - external quartz tube ; 32 - inner quartz tube.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Please refer to Fig. 6 and Fig. 7, an embodiment of the present invention provides an atomic fluorescence spectrometer based on dielectric barrier discharge-induced vapor generation, including a sample introduction system 100, a detection system 200, a control system 300 and a gas path system, the The detection system 200 is provided with an atomizer 201, a hollow cathode lamp light source 202 surrounding the atomizer 201 to excite a fluorescent signal, a photomultiplier tube 203 for converting the fluorescent signal into an electrical signal, and the The photomultiplier tube 203 is connected to the signal processor 204 , the control system 300 is provided with a control module and a display, and the gas circuit system includes a hydrogen source 500 and an argon source 400 .

The sample introduction system 100 is a DBD-CVG (dielectric barrier discharge-induced vapor generation) sample introduction system, and the detection system 200 is an AFS detection system.

The three ports of a tee 600 are respectively connected with the product outlet of the sample introduction system 100, the atomizer 201 and the hydrogen source 500 through pipelines, and the argon source 400 is connected with the sample introduction system 100 The carrier gas inlet is communicated with the atomizer 201 , and the hydrogen source 500 is directly connected with the carrier gas inlet of the sample introduction system 100 through a pipeline. The purpose of the argon gas source 400 communicating with the carrier gas inlet of the sample introduction system 100 is to provide the sample introduction system 100 with a discharge gas for forming a plasma, and also as a carrier gas to help make the sample The introduction system 100 generates hydride vapors of the analyte elements, and the purpose of the hydrogen source 500 communicating with the carrier gas inlet of the sample introduction system 100 is that it is difficult for the auxiliary part to realize the vapor generation of the elements to be converted into hydrides. The purpose of the hydrogen source 500 being connected to the atomizer 201 through the tee 600 is to increase the hydrogen content entering the atomizer 201 so that the analyte can be reduced to The elemental atoms provide enough reducing agent, and at the same time, the speed of the element to be measured entering the atomizer 201 can be accelerated, so as to speed up the test process. The purpose of connecting the argon gas source 400 to the atomizer 201 is to form an argon gas wall in the atomizer 201, reduce the oxygen content in the atomizer 201, and provide the required amount for the atomization process. Restorative atmosphere.

After the element to be measured is reduced to elemental atoms by hydrogen and high temperature in the atomizer 201, it is excited by the hollow cathode lamp light source 202 surrounding the atomizer 201 and emits a fluorescent signal. The signal is converted into an electrical signal by the photomultiplier tube 203 and then received by the signal processor 204. The signal processor 204 analyzes and processes the received fluorescent signal to obtain the content of the element to be measured.

The control module is connected with the gas circuit system and the detection system 200 to control the output of the gas circuit system and the amount of hydrogen and argon, and to control the work of each component of the detection system 200. The display uses It is used to display the hydrogen and argon volumes output by the gas path system, and to display the working status of each component of the detection system 200 and the analysis and processing results of the signal processor 204 .

The DBD-CVG sample introduction system of the present invention includes inner electrodes 10 , 22 , 31 , outer electrodes 16 , 19 , 28 and reactors 11 , 20 with cavities. The reactors 11, 20 are provided with product outlets 12, 18, 27 and waste outlets 13, 21 communicating with the cavities.

Example 1

Please refer to Fig. 1, a sampling system 6 communicates with the cavity and its nozzle extends into the cavity. , the other end is provided with the large ventilation tube of the nozzle and the thin tube connecting the sampling hose 7 until the nozzle, a carrier gas inlet 8 is located at the large ventilation tube, and the carrier gas is in the ventilation tube. Flow between the large tube and the thin injection tube and enter the cavity through the nozzle, so that the carrier gas inlet 8 is indirect communication with the cavity, and the sample solution is located between the injection hose 7 and the cavity. In the thin tube of sample injection, and when sprayed out by the nozzle, it is vaporized or atomized to form an aerosol.

The reactor 11 is a bottle-shaped structure with a bottom seal and a bottleneck and a bottle mouth on the top. The large ventilation pipe passes through the bottleneck and seals the bottleneck, and part of the large ventilation pipe extends into the cavity Inside, the nozzle is an inverted cone and is located at the bottom of the large vent tube, which is a transparent glass tube through which the thin sample injection tube can be seen. One end of the thin sample injection tube is connected to the sample injection hose 7, and the other end extends downward until extending into the nozzle, so as to guide the sample solution in the injection hose 7 into the nozzle.

The external electrode 16 is a conductor electroplated on the outer wall of the nozzle or a conductive sheet wrapped around the outer wall of the nozzle or a conductive wire wound on the outer wall of the nozzle, and is located in the cavity. The inside of the internal electrode 10 is filled with conductive material, and the outside is an insulating dielectric barrier layer 15 . The conductive material and the external electrode 16 are connected to each other through wires and an AC power source 9 .

The dielectric barrier layer 15 is a hollow structure made of glass, quartz or ceramics, and the conductive material filled inside is a saturated electrolyte solution or conductive glue, and the hollow structure includes a hollow structure located in the cavity. The sphere 14 and the hollow cylinder connected to the hollow sphere 14 and partly passing through the cavity wall of the cavity protrude outside the cavity, the dielectric barrier layer 15 is placed horizontally and perpendicular to the nozzle, so The sampling system 6 is located at the top of the reactor 11, and the aerosol ejected by the nozzle collides with the hollow sphere 14 when falling down.

When the external electrode 16 and the internal electrode 10 are connected through the AC power supply 9, a stable plasma will be generated between the internal electrode 10 and the external electrode 16, and the sample solution will become the At the same time, the aerosol reacts chemically with the plasma to produce analyte element vapor (such as the vapor product of lead). Since the aerosol reacts with the plasma as soon as it is formed, the premature formation of the aerosol is avoided. The resulting aerosol condenses in the container or the loss of aerosol caused by diffusion and overflow. The vapor of the analyte element enters the AFS detection system along with the carrier gas discharged from the product outlet 12, and when the sample solution or the aerosol falls away from the nozzle and falls, the liquid droplets will collide with the hollow Sphere 14 collides, and one of the effects of described hollow sphere 14 here is to act as collision ball, is used for eliminating large droplet, effectively controls the amount that large droplet enters AFS detection system from described product outlet 12, thereby reduces The influence of large droplets on the atomizer improves the stability of the signal.

The product outlet 12 is located below the internal electrode 10 and higher than the waste outlet 13 , and the waste outlet 13 is located at the bottom of the reactor 11 . After the reacted solution is separated from gas and liquid in the reactor 11, the waste liquid is discharged by gravity through the waste discharge port 13, and the vapor of the analyte discharged through the product outlet 12 is combined with the vapor of the gas path system. The hydrogen gas provided by the hydrogen source is mixed and then introduced into the AFS detection system. In the AFS detection system, the atomization is first realized by the atomizer, and then excited by the hollow cathode light source, and then the light signal is converted into electricity by the photomultiplier tube. signal, and finally realize the recording of signal strength through the signal processing module and display.

Taking the sample solution as a lead-containing solution as an example, the distance between the nozzle and the hollow sphere 14 is 5mm, the injection speed of the lead-containing solution is 2ml min ^-1 , and the carrier gas is argon, from The carrier gas inlet 8 enters, and forms a negative pressure at the nozzle, thereby realizing that the lead-containing solution is injected from the sampling thin tube through self-suction, and finally forms the aerosol. The AC power supply 9 is a high-frequency AC power supply with a peak output voltage of 2000-15000V (about 14000V in this embodiment), so that stable plasma is generated between the inner electrode 10 and the outer electrode 16 body, the hollow cathode lamp is a lead hollow cathode lamp, and Fig. 4 is a fluorescent signal diagram using the present invention to measure a blank and a lead standard sample.

Example 2

Please refer to FIG. 2 , a sampling system 17 is located at the upper end of the reactor 20 , and is a sampling tube with its nozzle facing downwards, which is a trumpet-shaped structure facing downwards. The injection tube extends into the interior of the reactor 20 .

The outer electrode 19 is a conductor electroplated on the outer wall of the reactor 20 or a conductive sheet wrapped around the outer wall of the reactor 20 or a conductive wire wound on the outer wall of the reactor 20. The inner electrode 22 The inside is filled with conductive material, and the outside is an insulating dielectric barrier layer 23. The conductive material is connected to the external electrode 19 through the AC power source 26. Preferably, the conductive material is a metal rod or a graphite rod. The internal electrode 22 is arranged vertically, inserted into the reactor 20 from the bottom of the reactor 20 upwards, and its central axis coincides with the central axis of the nozzle. The tail portion of the internal electrode 22 is left outside the reactor 20, and is connected to the AC power supply 26 through the tail portion left outside, the upper end of the internal electrode 22 is sealed, and the upper end of the internal electrode 22 passes through The surrounding of the outer electrode 19 faces the nozzle.

The maximum diameter of the trumpet-shaped structure ≥ the diameter of the internal electrode 22, preferably slightly greater than or equal to the diameter of the internal electrode 22, so that the sample solution can be evenly introduced to the surface of the internal electrode 22, so that the When the sample solution falls from the horn structure to the surface of the dielectric barrier layer 23, a liquid film will be formed on the surface of the dielectric barrier layer 23, which can increase the contact area between the plasma and the sample solution.

The product outlet 18 is directly communicated with the reactor 20, located above the outer electrode 19, facing the inner electrode 22 and protruding from the upper end area surrounded by the outer electrode 19, and the carrier gas inlet 24 is located at the upper end area surrounded by the outer electrode 19. Below the outer electrode 19 and on the side opposite to the product outlet 18 , the waste outlet 21 is located at the lower end of the reactor 20 , lower than the height of the carrier gas inlet 24 .

After the AC power supply 26 is turned on, a stable plasma is formed between the inner electrode 22 and the outer electrode 19, and the liquid film on the inner electrode 22 is thin and uniform, and can quickly react with the plasma Produce the analyte element vapor containing the analyte element (such as the analyte element vapor containing cadmium element), the carrier gas entering from the carrier gas inlet 24 moves upwards, which can separate the gas-liquid to a certain extent, and then carry upward The element vapor to be measured is discharged to the product outlet 18 and introduced into the AFS detection system. In the AFS detection system, the atomization is first realized by an atomizer, then excited by a hollow cathode lamp, and then passed through a photomultiplier tube. The optical signal is converted into an electrical signal, and finally the signal strength is recorded through the signal processing module and the display. The waste liquid is discharged from the waste discharge port 21 under the action of its own gravity.

Taking the sample solution as a cadmium-containing solution as an example, the dielectric barrier layer 23 of the internal electrode 22 is a glass tube with an inner diameter of 2mm, an outer diameter of 3.5mm, and a length of 85mm, and the specification of the reactor 20 is an inner diameter of 5mm, outer diameter 7mm, length 95mm, also made of glass material, cadmium-containing solution flows into the reactor 20 from the nozzle at a flow rate of 3mL min ^-1 , the carrier gas (Ar: 300mL min ^-1 , H ₂ : 60 mL min ⁻¹ ) enters the reactor 20 through the carrier gas inlet 24 . The AC power supply 26 is a high-frequency AC power supply with a peak output voltage of 2000-15000V (about 14000V in this embodiment), so that stable plasma is generated between the inner electrode 22 and the outer electrode 19 body, the hollow cathode lamp is a cadmium hollow cathode lamp, and Fig. 5 is a fluorescent signal diagram of a blank and a cadmium standard sample measured using the present invention.

Example 3

Please refer to FIG. 3 , the DBD-CVG sample introduction system is a dipping type dielectric barrier discharge vapor generator. The dipping type dielectric barrier discharge device includes two concentric quartz tubes 29, 32, the length of the two quartz tubes 29, 32 is 80 mm, and one end of the inner quartz tube 32 is sealed. The cavity between the outer quartz tube 29 (outer diameter 8 mm, inner diameter 6 mm) and inner quartz tube 32 (outer diameter 4 mm, inner diameter 2 mm) serves as a discharge chamber. A copper rod is inserted into the inner quartz tube 32 as the inner electrode 31 , and the copper foil wrapped on the outer layer of the outer quartz tube 29 is used as the outer electrode 28 . The inner quartz tube 32 of the device adopts a detachable design and serves as a sampling tool. The sealed end of the inner quartz tube 32 is inserted into the sample containing mercury, and after sampling for 10 seconds, the inner quartz tube 32 loaded with the sample is inserted into the discharge chamber, and then the AC power supply 34 is connected, and the sample is discharged Under the action of the generated plasma, steam is generated and atomized, and the finally generated mercury vapor enters the AFS detection system through the product outlet 27 under the purging of the carrier gas entering from the carrier gas inlet 30, and is excited by the mercury hollow cathode lamp , and then convert the optical signal into an electrical signal through a photomultiplier tube, and finally record the signal intensity through a signal processing module and a display.

The carrier gas is not limited to the above gases, and may also be other inert gases or mixed inert gases. It can also be one or a mixed gas of Ar and He, and other reactive gases such as hydrogen, ethylene, methane, carbon dioxide, carbon monoxide, etc. can also be added.

The sample solution can be directly entered into the DBD-CVG sample introduction system to realize steam generation, or the effect of steam generation can be enhanced by adding small molecular organic substances such as formic acid, acetic acid, methanol, ethanol, etc. In addition, the pH value of the solution also depends on different The elements are selected for proper conditions to carry out vapor generation.

In this article, the orientation words such as front, rear, upper, and lower involved are defined by the parts in the drawings and the positions between the parts in the drawings, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the location words should not limit the scope of protection claimed in this application.

In the case of no conflict, the above-mentioned embodiments and features in the embodiments herein may be combined with each other.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. A sample introduction system based on dielectric barrier discharge-induced vapor generation, characterized in that: comprise an inner electrode, an outer electrode and a reactor with a cavity, the reactor is provided with a product outlet communicated with the cavity and a waste discharge port, a carrier gas inlet communicates directly or indirectly with the cavity, a sampling system communicates with the cavity and its nozzle extends into the cavity, and one end of the inner electrode extends into the cavity The cavity is facing the nozzle, and the other end passes through the reactor and is connected to the external electrode through an AC power supply. The external electrode is facing the end of the internal electrode extending into the cavity, and covered The outer wall of the nozzle or the outer wall covering the reactor, the sample solution sprayed out by the nozzle will collide with the inner electrode when falling down. 2. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 1, characterized in that: the sample introduction system is an atomizer, comprising a sample injection hose with a plug at one end and a plug at the other end. There is a large vent pipe of the nozzle and a thin sample tube connecting the sampling hose to the nozzle, the carrier gas inlet is arranged in the large vent pipe, and the carrier gas is connected between the large vent pipe and the large vent pipe. The sample solution flows between the thin tubes and enters the cavity through the nozzle, and the sample solution is located in the thin tube and forms an aerosol when sprayed out by the nozzle. 3. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 2, characterized in that: the external electrode is a conductor electroplated on the outer wall of the nozzle or a conductive sheet wrapping the outer wall of the nozzle or is A conductive wire wound on the outer wall of the nozzle; the inside of the inner electrode is filled with a conductive material, and the outside is an insulating dielectric barrier layer, and the conductive material is connected to the outer electrode through the AC power supply. 4. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 3, characterized in that: the dielectric barrier layer is a hollow structure made of glass, quartz or ceramics, and the conductive material filled inside It is a saturated electrolyte solution or conductive glue, the dielectric barrier layer is placed horizontally and perpendicular to the nozzle, and the hollow structure includes a hollow sphere in the cavity and a hollow sphere that is connected to the hollow sphere and partially protrudes The hollow cylinder outside the cavity, the sampling system is located at the top of the reactor, and the aerosol ejected by the nozzle collides with the hollow sphere when falling down. 5. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 4, characterized in that: the product outlet is located below the inner electrode and higher than the waste discharge port, and the waste discharge The port is located at the bottom of the reactor. 6. the sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 1, is characterized in that: described sample introduction system is positioned at the upper end of described reactor, is sampling tube, and its nozzle is arranged downwards, and The outer electrode is a conductor electroplated on the outer wall of the reactor or a conductive sheet wrapped around the outer wall of the reactor or a conductive wire wound on the outer wall of the reactor. The inside of the inner electrode is filled with conductive material, and the outer electrode It is an insulating dielectric barrier layer, the conductive material is connected to the external electrode through the AC power supply, the internal electrode is vertically arranged, and its upper end is sealed, and the upper end of the internal electrode passes through the surrounding of the external electrode, face the nozzle. 7. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 6, characterized in that: the nozzle is a horn-shaped structure facing downwards, and the maximum diameter of the horn-shaped structure is greater than or equal to the inner electrode When the sample solution falls from the horn structure onto the surface of the dielectric barrier layer, a liquid film will be formed on the surface of the dielectric barrier layer. 8. The sample introduction system based on dielectric barrier discharge induced vapor generation as claimed in claim 6, characterized in that: the product outlet communicates with the reactor, is located above the outer electrode, and faces the inner electrode protruding from the upper end area surrounded by the outer electrode, the carrier gas inlet is located below the outer electrode and on the side opposite to the product outlet, the waste discharge port is located in the lower end area of the reactor, lower than the height of the carrier gas inlet. 9. The sample introduction system based on dielectric barrier discharge induced vapor generation according to claim 1, wherein the carrier gas is an inert gas or a mixed gas of an inert gas and hydrogen or a mixed inert gas. 10. An atomic fluorescence spectrometer based on dielectric barrier discharge-induced vapor generation, characterized in that: comprising the sample introduction system based on dielectric barrier discharge-induced vapor generation according to any one of claims 1 to 9, also comprising a detection system, A control system and a gas path system, the detection system is equipped with an atomizer, a hollow cathode lamp light source surrounding the atomizer to excite a fluorescent signal, a photomultiplier tube for converting the fluorescent signal into an electrical signal, and A signal processor connected with the photomultiplier tube, a control module and a display are arranged in the control system, the gas circuit system includes a hydrogen source and an argon source, and three ports of a three-way are respectively introduced into the The product outlet of the system, the atomizer and the hydrogen source are communicated through pipelines, the argon source is communicated with the carrier gas inlet of the sample introduction system and the atomizer, and the hydrogen source is connected with the sample The carrier gas inlet introduced into the system is directly connected through a pipeline, and the control module is connected with the gas circuit system and the detection system to control the amount of hydrogen and argon output by the gas circuit system, and to control the output of the detection system. For the work of each component, the display is used to display the output hydrogen and argon volumes of the gas path system, display the working status of each component of the detection system, and display the processing results of the signal processor.