3D printing pump-free sample injection point discharge atomic emission spectrum analysis device and method for detecting arsenic

Abstract

The invention discloses a 3D printing pump-free sample injection point discharge atomic emission spectrum analysis device and method for detecting arsenic, and belongs to the technical field of atomic emission spectrum analysis. Comprising a 3D printing integrated device, an external gas path system and a spectrum detection system, the 3D printing integrated device comprises a 3D printing module, a quartz glass sheet, a quartz capillary tube, two tungsten filament electrodes and a microsyringe; the external gas path system comprises a small argon steel cylinder, two argon pipelines, a gas flow meter and a trace gas flow meter; the spectrum detection system comprises an optical fiber and a small CCD spectrometer. The method comprises the following steps: injecting an arsenic-containing solution sample into a reaction chamber of a 3D printing device by using a microsyringe, converting the arsenic-containing solution sample into a gaseous analyte through hydride generation, blowing the gaseous analyte into a discharge chamber by argon, exciting an atomic emission spectrum of arsenic by using micro plasma, radially collecting a spectral signal from the outside of a quartz capillary by using a bare optical fiber, and transmitting the spectral signal to a CCD (Charge Coupled Device); and finally, the concentration of the arsenic in the sample can be obtained through calculation. The method has the characteristics of high excitation efficiency, strong anti-interference capability, low cost, open source sharing, environmental friendliness and the like.

Description

Technical Field

[0001] This application relates to the field of atomic emission spectroscopy analysis technology, and in particular to a 3D-printed pumpless tip discharge atomic emission spectroscopy analysis device and method for detecting arsenic. Background Technology

[0002] For the detection of metal ions, atomic emission spectrometry is a commonly used method, but it is often limited by application scenarios. The large size, complex structure, high gas consumption, and high operating costs of these instruments often limit their use to the laboratory. To meet the requirements of some trace and rapid on-site analyses, instrument integration and miniaturization are crucial. Microplasma-based atomic emission spectrometry has emerged as a promising method for portable, low-cost, and rapid trace analysis. Tip discharge generates high-energy plasma capable of exciting atomic emission spectra, but the inherently small discharge volume limits the effective introduction of analytes, which is a major bottleneck for sensitivity and repeatability. Among chemical vapor generation methods, hydride generation stands out for its high efficiency, arsenic selectivity, and compatibility with water samples. However, integrating hydride generation with microplasma systems remains challenging due to dead volume, sample loss, and dependence on peristaltic pumps and complex tubing.

[0003] 3D printing (additive manufacturing) is an advanced manufacturing process that uses digital models to build three-dimensional entities by layering materials. Its computer-controlled precision forming process demonstrates significant advantages in achieving high-degree-of-freedom design, rapid prototyping, and the formation of complex geometries, providing a new technological path for the manufacture of complex devices. Compared to traditional machining, 3D printing not only enables the integrated forming of complex geometries, significantly reducing assembly errors and leakage risks, but also offers significant advantages such as easy integration, low manufacturing costs, rapid iteration, and cross-platform sharing. 3D printing's cross-platform sharing mechanism based on open-source design files makes it possible to reproduce equipment across multiple laboratories. Therefore, it is possible to integrate gas-liquid pipelines, reaction chambers, and detection components using 3D printing technology, thereby minimizing leakage risks, dead volumes, and assembly errors. This capability opens up new avenues for miniaturized, open-source, and field-deployed analysis platforms. Summary of the Invention

[0004] This invention addresses the technical problems existing in the background art by proposing a 3D-printed pumpless capillary tip discharge atomic emission spectrometry (CPI) device and method for arsenic detection. The device utilizes 3D printing technology to construct an integrated capillary tip discharge hydride generation atomic emission spectrometry (CPI) device, integrating the gas-liquid pipeline, reaction chamber, and excitation source. This significantly reduces the device's size and minimizes dead volume loss caused by the pipeline. Compared to traditional tip discharge, the capillary restricts the diffusion of micro-plasma and gaseous analytes, allowing more gaseous analytes to enter the micro-plasma for excitation, thus improving sample excitation efficiency. The use of a micro-injector and a micro-gas flow meter enables sample detection with low sample and gas consumption.

[0005] To solve the technical problem, the technical solution of the present invention is as follows:

[0006] A 3D-printed pumpless tip discharge atomic emission spectrometer for detecting arsenic, the device comprising: an integrated module, an external gas path system, and a spectroscopic detection system;

[0007] The integrated module internally forms a reaction chamber and a discharge mounting area located at the end of a quartz capillary. The reaction chamber has a sample inlet at the top and a carrier gas inlet on the side. A quartz capillary is inserted and fixed within the discharge mounting area, creating a discharge space for a tip discharge micro-plasma within its inner cavity. Two electrodes are spaced axially within the quartz capillary to form a tip discharge micro-plasma between the electrodes within the capillary's inner cavity. The quartz capillary is connected to the gas outlet of the reaction chamber, used to introduce and transport the gaseous analyte generated in the reaction chamber into the capillary's inner cavity. A plasma sustaining gas inlet is located on the discharge mounting area, used to introduce sustaining gas into the end of the quartz capillary, allowing the sustaining gas and gaseous analyte to enter the capillary's inner cavity and flow through the discharge area. The side end of the quartz capillary serves as a downstream outlet for gas discharge.

[0008] The quartz capillary is a hollow, straight quartz tube with two ports on either side. Inside the discharge chamber, there are two air inlets perpendicular to the tube. Two tungsten wires are inserted from the two ports of the capillary. The gas outlet of the reaction chamber is connected to one of the vertical air inlets of the quartz capillary via an internal channel of the 3D printing module, used to transport the gaseous analyte generated in the reaction chamber into the capillary. The discharge chamber is located between the two electrodes inside the quartz capillary, and it is connected to the other vertical air inlet through an internal channel of the 3D printing module to introduce discharge gas, thereby forming a stable tip discharge micro-plasma within the quartz capillary.

[0009] The quartz capillary is not sealed; rather, it receives gaseous analytes from the reaction chamber and discharge gas from the second gas path, mixes and discharges them inside the tube, and is fixed by mounting holes on the 3D printing module.

[0010] The discharge chamber is essentially a section of space inside a capillary; it has two functions:

[0011] Electrode installation:

[0012] Two tungsten wires are inserted from both sides of the discharge chamber;

[0013] Entering the interior of the quartz capillary;

[0014] A discharge gap is formed inside the tube;

[0015] Gas introduction:

[0016] Ar gas is first introduced into the internal channel of the 3D printing module;

[0017] Then from the internal channel → capillary port → inside the tube;

[0018] The external gas path system is used to provide independently controllable airflow to the carrier gas inlet of the reaction chamber and the air inlet of the discharge chamber, respectively.

[0019] The spectral detection system includes an optical fiber spectral probe disposed on the side of the quartz capillary for collecting the spectral signals emitted by the microplasma.

[0020] Furthermore, the two electrodes are tungsten wire electrodes arranged in parallel, including a right tungsten wire electrode and a left tungsten wire electrode.

[0021] Furthermore, the fiber optic spectral probe includes a bare optical fiber, the end face of which is radially aligned with the middle of the quartz capillary.

[0022] Furthermore, the external gas path system includes a gas source (preferably a small argon cylinder), a main path, a main flow meter (gas flow meter), and two parallel branch paths. The gas source is connected to the main path, the main flow meter (gas flow meter) is installed on the main path, the main path is connected to the two parallel branch paths, a micro gas flow meter is installed on the first gas path, and the flow rate of the second gas path is jointly controlled by the main flow meter and the first gas path flow meter, or a micro gas flow meter can be installed separately; one branch path is connected to the carrier gas inlet, and the other branch path is connected to the gas inlet.

[0023] Furthermore, the gas source is an inert gas source.

[0024] Furthermore, the inert gas is argon.

[0025] Furthermore, the inner cavity of the quartz capillary constitutes the discharge space of the tip discharge microplasma, i.e., the discharge chamber. A 3D-printed pumpless tip discharge atomic emission spectrometry method for detecting arsenic, the method being applied to any of the above-described devices, the method comprising:

[0026] S1: Turn on the external gas path system and supply power to the electrode to form a stable tip discharge micro-plasma in the quartz capillary;

[0027] S2: Inject an arsenic-containing sample solution and a hydride generating reagent into the reaction chamber through the injection port, so that they react to generate gaseous arsenic hydride;

[0028] S3: The carrier gas introduced through the carrier gas inlet purges and transports the gaseous arsenic hydride to the discharge chamber, where it is excited to generate an atomic emission spectrum in the micro-plasma within the quartz capillary.

[0029] S4: The atomic emission spectrum is acquired by the spectral detection system, and the arsenic concentration in the sample is calculated based on the intensity of the characteristic spectral lines of arsenic and the calibration curve.

[0030] This application has the following advantages:

[0031] (1) The innovative use of 3D printing technology integrates the gas-liquid pipeline, reaction chamber and excitation source into one unit, reducing the size of the device.

[0032] (2) The use of a micro-syringe-based injection method to replace the traditional peristaltic pump achieves precise micro-sample delivery with low dead volume and low sample loss.

[0033] (3) A micro gas flow meter was used to control the gas flow rate, which enabled the maintenance of micro plasma and the delivery of gaseous analytes with low gas consumption.

[0034] (4) Capillary tip discharge serves as the excitation source, effectively confining the gaseous analytes and microplasma inside the capillary. The gaseous analytes can enter the microplasma more effectively and fully participate in the excitation process, thereby improving the excitation efficiency.

[0035] (5) The capillary tip discharge serves as an excitation source and is integrated with the atomic emission spectroscopy analysis device. It is small in size, low in power consumption, low in cost, and easy to operate, which is conducive to the miniaturization and integration of atomic emission spectroscopy analysis instruments and their application in on-site analysis. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the 3D-printed pumpless micro-sample hydride generation capillary tip discharge atomic emission spectrometry analysis device for detecting arsenic according to the present invention.

[0038] Figure 2 This is a schematic diagram of the internal structure of the 3D printing module;

[0039] Figure 3 This invention employs hydride generation as a sample introduction method for the detection of arsenic and obtains characteristic atomic emission spectra.

[0040] Figure 4 This invention uses hydride generation as a sample introduction method for the detection of arsenic, and obtains a calibration curve.

[0041] Figure 5 This invention employs hydride generation as a sample introduction method for the detection of tin, and obtains characteristic atomic emission spectra.

[0042] Figure 6 This invention employs hydride generation as a sample introduction method for the detection of germanium and obtains characteristic atomic emission spectra.

[0043] Explanation of icon numbers:

[0044] 1-Micro-injector; 2-Left tungsten wire electrode; 3-Right tungsten wire electrode; 4-Quartz capillary; 5-Discharge chamber; 6-Reaction chamber; 7-Quartz glass plate; 8-First gas path; 9-Second gas path; 10-Gas flow meter; 11-Micro gas flow meter; 12-Small argon cylinder; 13-Bare optical fiber; 14-Power supply. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Example 1:

[0047] like Figure 1 and 2 As shown, this application provides a 3D-printed pumpless micro-sample hydride generation capillary tip discharge atomic emission spectrometry analysis device for the detection of arsenic, such as... Figure 1 As shown, it includes a micro-injector 1, a left tungsten wire electrode 2, a right tungsten wire electrode 3, a quartz capillary tube 4, a discharge chamber 5, a reaction chamber 6, a quartz glass plate 7, a first gas path 8, a second gas path 9, a gas flow meter 10, a micro gas flow meter 11, a small argon gas cylinder 12, a bare optical fiber 13, and a power supply 14.

[0048] The micro-sampler 1 is used to inject trace amounts of sample and hydride-generating chemical reagents into the reaction chamber 6 through the injection port; the left tungsten wire electrode 2 is an important component of the tip discharge system, mainly used to generate micro-plasma; the right tungsten wire electrode 3 is an important component of the tip discharge system, mainly used to generate micro-plasma; the quartz capillary 4 restricts the diffusion of micro-plasma and gaseous analytes, allowing more gaseous analytes to enter the micro-plasma for excitation, thus improving the sample excitation efficiency; the discharge chamber 5 is used for tip discharge to form micro-plasma to excite the emission spectrum of the analyte atoms; the reaction chamber 6 is used for the mixing and reaction of trace amounts of sample and hydride-generating chemical reagents to generate gaseous analytes; the quartz glass plate 7 seals the reaction chamber 6 for easy observation of the reaction; the first gas path 8 purges the gaseous analytes generated in the reaction chamber 6 into the capillary tip discharge micro-plasma excitation source; the second gas path 9 maintains the gas atmosphere required for micro-plasma discharge; the gas flow meter 10 controls the total gas flow rate; the micro gas flow meter 11 controls the gas flow rate of the two branches 8 and 9. The small argon cylinder 12 provides argon gas as a carrier gas and discharge gas, which is broken down by high voltage to generate a tip discharge micro-plasma. The bare optical fiber 13 collects the light from the atomic emission spectrum and transmits it to a small CCD spectrometer to obtain the characteristic atomic emission spectrum of the analyte arsenic and measure the intensity of its atomic emission lines. The power supply 14 serves as the power source for the tip discharge micro-plasma.

[0049] The specific structure of the 3D printing integrated module is as follows: The 3D printing integrated module includes a reaction chamber 6 and a discharge chamber 5; the reaction chamber 6 is covered with a quartz glass plate 7 to form a sealed space for observing the reaction, and has an opening on the left side as the gas path 8 inlet, and openings on the top as the sample injection ports for the micro-sampler 1; the discharge chamber 5 has a quartz capillary tube 4 inserted into the fixing hole of the 3D printing module, and two tungsten wire electrodes 2 and 3 are inserted into the quartz capillary tube from both sides and fixed at a fixed distance to generate discharge micro-plasma, the quartz capillary tube 4 is provided with gas inlet and outlet, and the opening above the tungsten wire electrode inlet on the left side of the discharge chamber 5 is used as the gas path 9 inlet.

[0050] The external gas path system consists of a small bottle of high-purity argon gas 12, whose total flow rate is controlled by a gas flow meter 10. The gas is then divided into two gas paths 8 and 9, whose flow rates are controlled by a micro gas flow meter 11. These paths are connected to the inlet of the reaction chamber 6 of the 3D printing device to purge the gaseous analytes generated in the reaction chamber 6 into the capillary tip discharge micro-plasma excitation source and the inlet of the discharge chamber 5 to maintain the gas atmosphere required for micro-plasma discharge.

[0051] The spectral detection system includes a bare optical fiber 13 and a small CCD spectral detector. The bare optical fiber 13 is placed outside the quartz capillary tube 4 to collect spectral signals radially and then transmits them to the small CCD spectral detector for spectral acquisition.

[0052] Furthermore, the 3D printing module measures 2.5 × 1.5 × 3 cm (length × width × height), the reaction chamber 6 is teardrop-shaped, 9.6 mm high, 1.1 mm wide at the top, 6 mm wide at the bottom, and 9.7 mm deep; the quartz glass plate 7 measures 15 × 10 × 0.2 mm (length × width × height).

[0053] Furthermore, the quartz capillary 4 is 30 mm long, with an inner diameter of 0.8 mm and an outer diameter of 1.5 mm. The tungsten wire electrodes 2 and 3 are 40 mm long, and the distance between the two tungsten wire electrodes 2 and 3 is 2 mm.

[0054] Furthermore, a 1.5 mm diameter circular hole is used as the inlet for gas passages 8 and 9, and a 0.7 mm diameter circular hole is used as the inlet for micro-syringe 1.

[0055] Furthermore, the bare optical fiber 13 has a diameter of 1 mm.

[0056] This application discloses a 3D-printed pump-free micro-sample hydride generation capillary tip discharge atomic emission spectrometry method for detecting arsenic. The method utilizes the aforementioned 3D-printed pump-free micro-sample hydride generation capillary tip discharge atomic emission spectrometry analysis device for arsenic detection. The specific process is as follows:

[0057] After turning on the power supply 14 and the two gas channels 8 and 9 and waiting for the gas flow and discharge to stabilize, the sample solution containing the analyte element arsenic and the hydride reaction reagent are injected into the reaction chamber 6 through the injection port using the micro-syringe 1. The gaseous analyte element produced is swept into the capillary tip discharge micro-plasma excitation source by the gas flow entering from the gas inlet of the reaction chamber 6, and is excited to generate an atomic emission spectrum signal.

[0058] Specifically, to make it more intuitive, we will focus on the intersection of the two gas paths at the capillary inlet:

[0059] First gas path 8 (sample transport line): carrying gaseous arsenic hydride (AsH3), flows out from reaction chamber 6 and arrives at the inlet of quartz capillary 4.

[0060] Second gas path 9 (plasma lifeline): The external gas path connects to the internal channel of the 3D printing module, and meets and mixes with the first gas path at another inlet of the quartz capillary 4.

[0061] Mixing and Excitation: After the two gas streams mix inside capillary 4, they are jointly introduced into the interior of capillary 4 and flow into discharge chamber 5 (micro-plasma). AsH3 is excited here.

[0062] Unified discharge: All gases (waste gas after reaction, residual argon, etc.) are discharged as a whole from the side end of the capillary. The bare optical fiber 13 collects the light of the atomic emission spectrum transmitted through the quartz capillary 4 and transmits it to a small CCD spectrometer to obtain the characteristic atomic emission spectrum of the analyte element arsenic, and measures the intensity of its atomic emission spectral lines. Finally, the arsenic concentration of the solution sample is calculated using the calibration curve.

[0063] In one exemplary embodiment, the 3D-printed pumpless micro-sample hydride-generating capillary tip discharge atomic emission spectrometry analysis device for arsenic detection uses capillary tip discharge as the sample excitation source: An arsenic solution containing dilute hydrochloric acid and borohydride reagent are injected into the reaction chamber 6 using a micro-injector 1. The mixture reacts to generate a gaseous analyte. Under the action of the gas path 8, the gaseous analyte enters the capillary tip discharge excitation source, is excited, and generates an atomic emission spectrum signal. The bare optical fiber 13 collects the light transmitted through the quartz capillary 4 and transmits it to a small CCD spectrometer to obtain the characteristic atomic emission spectrum and calibration curve (linear range 10-3000 μg L⁻¹) of the analyte arsenic. Figure 3 and 4 As shown.

[0064] In one exemplary embodiment, a tin-containing sample solution is analyzed using the 3D-printed pumpless micro-sample hydride generation capillary tip discharge atomic emission spectrometry analysis device and method of this application, ultimately obtaining a characteristic atomic emission spectrum, such as... Figure 5 As shown.

[0065] In one exemplary embodiment, a sample solution containing germanium is analyzed using the 3D-printed pumpless micro-sample hydride generation capillary tip discharge atomic emission spectrometry analysis device and method of this application, ultimately obtaining a characteristic atomic emission spectrum, such as... Figure 6 As shown.

[0066] In this device, 3D printing technology is used to integrate the gas-liquid pipeline, reaction chamber, and excitation source, significantly reducing the device's volume and minimizing dead volume loss caused by the pipelines. Compared to traditional tip discharge, the capillary restricts the diffusion of micro-plasma and gaseous analytes, allowing more gaseous analytes to enter the micro-plasma for excitation, thus improving sample excitation efficiency. The use of a micro-injector 1 and a micro-gas flow meter 11 enables sample detection with low sample and gas consumption. It can be seen that the 3D-printed pump-free micro-sample hydride capillary tip discharge atomic emission spectrometry analysis device and method of this invention has the advantages of high excitation efficiency, strong anti-interference ability, low cost, open-source sharing, and environmental friendliness when detecting arsenic.

[0067] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0068] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A 3D-printed pumpless tip discharge atomic emission spectrometer for detecting arsenic, characterized in that, The device includes: an integrated module, an external gas path system, and a spectral detection system; The integrated module internally forms a reaction chamber and a discharge mounting area located at the end of a quartz capillary. The reaction chamber has a sample inlet at the top and a carrier gas inlet on the side. A quartz capillary is inserted and fixed within the discharge mounting area, creating a discharge space for a tip discharge micro-plasma within its inner cavity. Two electrodes are spaced axially within the quartz capillary to form a tip discharge micro-plasma between the electrodes within the capillary's inner cavity. The quartz capillary is connected to the gas outlet of the reaction chamber, used to introduce and transport the gaseous analyte generated in the reaction chamber into the capillary's inner cavity. A plasma sustaining gas inlet is located on the discharge mounting area, used to introduce sustaining gas into the end of the quartz capillary, allowing the sustaining gas and gaseous analyte to enter the capillary's inner cavity and flow through the discharge area. The side end of the quartz capillary serves as a downstream outlet for gas discharge. The external gas path system is used to provide independently controllable airflow to the carrier gas inlet of the reaction chamber and the air inlet of the discharge chamber, respectively. The spectral detection system includes an optical fiber spectral probe disposed on the side of the quartz capillary for collecting the spectral signals emitted by the microplasma.

2. The apparatus according to claim 1, characterized in that, The two electrodes are tungsten wire electrodes arranged in parallel.

3. The apparatus according to claim 1, characterized in that, The fiber optic spectral probe includes a bare optical fiber, the end face of which is radially aligned with the middle of the two electrodes in the quartz capillary.

4. The apparatus according to claim 1, characterized in that, The external gas path system includes a gas source, a main path, a main flow meter, and two parallel branch paths. The gas source is connected to the main path, the main flow meter is installed on the main path, the main path is connected to the two parallel branch paths, and each branch path is equipped with a micro gas flow meter; one branch path is connected to the carrier gas inlet, and the other branch path is connected to the air inlet.

5. The apparatus according to claim 4, characterized in that, The gas source is an inert gas source.

6. The apparatus according to claim 5, characterized in that, The inert gas used is argon.

7. The apparatus according to claim 1, characterized in that, The integrated module is a one-piece molded structure made using 3D printing technology.

8. The apparatus according to claim 1, characterized in that, The reaction chamber is covered with a quartz glass plate to form a sealed space.

9. The apparatus according to claim 1, characterized in that, The inner cavity of the quartz capillary forms the discharge space of the tip discharge micro-plasma, which is the discharge chamber.

10. A pumpless tip discharge atomic emission spectrometry method for detecting arsenic using 3D printing, characterized in that, The method is applied to the apparatus according to any one of claims 1-9, and the method includes: After turning on the power supply and both gas lines and waiting for the gas flow and discharge to stabilize, the sample solution containing the analyte arsenic and the hydride reaction reagent are injected into the reaction chamber through the injection port using a microsyringe. The gaseous analyte arsenic is then purged into the discharge chamber by the gas flow entering from the reaction chamber inlet, where it is excited and generates an atomic emission spectrum signal. The bare optical fiber collects the light from the atomic emission spectrum passing through the quartz capillary and transmits it to a small CCD spectrometer to obtain the characteristic atomic emission spectrum of the element to be measured, and measures the intensity of its atomic emission spectral lines. Finally, the arsenic concentration of the solution sample is obtained by calculation using the calibration curve.

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