Split type atomizer for ICP-MS and its manufacturing, assembling and particle size control method

Abstract

The application discloses a split type atomizer for ICP-MS and a manufacturing, assembling and particle size control method thereof, and belongs to the technical field of atomization devices. The atomizer comprises a main body shell, a gas path interface, a gas path channel, a central capillary, an atomization nozzle and an inverted taper joint. External gas enters the gas path channel through the gas path interface, and forms a high-speed shearing airflow at the atomization nozzle; sample solution is transported to a gas-liquid intersection area through the central capillary, and is sheared and broken by the high-speed airflow to form aerosol mist droplets. The inverted taper joint is used for fixing, sealing and positioning the central capillary, and the atomization nozzle is detachably connected with the main body shell, so that the nozzle structure can be quickly replaced and controlled. By optimizing the nozzle structure, the gas path convergence form and the capillary outlet position, the application can obtain a particle size distribution mainly in the form of fine mist droplets under typical atomization conditions, thereby improving sample utilization and reducing memory effect, and has the advantages of replaceable nozzle, flexible control and strong working condition adaptability.

Description

Technical Field

[0001] This invention relates to the field of atomization device technology, and more specifically, to a split-type atomizer for ICP-MS and its manufacturing, assembly and particle size control methods. Background Technology

[0002] Inductively coupled plasma mass spectrometry (ICP-MS) is a highly sensitive technique for trace element and isotope analysis, and its analytical performance largely depends on the efficiency of the sample introduction system. The sample introduction system typically consists of a nebulizer and a nebulization chamber. The nebulizer converts the liquid sample into aerosol microdroplets, while the nebulization chamber filters the aerosols, removing large droplets and allowing only small droplets to enter the plasma. Ideally, the droplet size distribution should be mainly concentrated in the 1 to 15 micrometer range. If the droplet size is too large, it can easily lead to increased plasma load, insufficient desolvation, intensified matrix effects, salt deposition at the interface cone, and signal drift. If the droplets are too small, the effective sample volume may be reduced due to low transmission efficiency, affecting analytical sensitivity. Furthermore, in single-particle ICP-MS analysis, the stability of droplet formation directly affects key performance indicators such as missed particle events, pulse broadening, relative standard deviation of peak height, and arrival time jitter.

[0003] Currently, commercially available ICP-MS atomizers, such as quartz concentric atomizers, glass atomizers, metal atomizers, and machined polymer atomizers, generally suffer from high processing costs, long structural iteration cycles, and difficulties in quickly optimizing nozzle geometry parameters. Especially for corrosive sample systems, the suitability of these materials is limited. In recent years, additive manufacturing technology has been attempted for the integrated molding of atomizers, offering advantages such as the ability to achieve complex internal flow channel designs, shorten iteration cycles, and enable low-cost customization. However, fully integrated 3D-printed atomizers still face many challenges in practical applications: for example, the manufacturing precision of key micro / nano structures such as nozzles is limited by the printing process and cannot be compared with precision machining; it is difficult to select a single material with strength, precision, and corrosion resistance for the main structure and wetted structure; once the nozzle becomes clogged, the entire atomizer is difficult to disassemble and clean, resulting in high maintenance costs; and if the nozzle geometry needs to be changed for parameter optimization, the entire atomizer often needs to be reprinted, leading to complex variable control and poor experimental reproducibility.

[0004] Therefore, it is necessary to provide a novel nebulizer structure that concentrates high-precision manufacturing on critical components such as the nozzle, while using low-cost, rapid manufacturing for non-critical load-bearing or non-liquid-contact structures such as the main body shell. By adopting a modular design, while ensuring assembly coaxiality and sealing, it achieves rapid nozzle replacement, adjustable particle size distribution, and easy instrument maintenance. This not only improves the nebulizer's yield and adaptability to various operating conditions but also provides a stable, efficient, and flexible sample introduction solution for ICP-MS analysis. Summary of the Invention

[0005] The purpose of this invention is to provide a split-type atomizer for ICP-MS and its manufacturing, assembly and particle size control method. The aim is to solve the problems of high manufacturing cost, long iteration cycle, difficult nozzle replacement and inconvenient particle size control of existing atomizers by designing the atomizer body and nozzle separately and manufacturing them in sections using different additive manufacturing processes. This will enable high-precision manufacturing of key components of the atomizer and low-cost rapid iteration of the main structure.

[0006] To solve the above-mentioned technical problems, the technical solution proposed in this application is as follows:

[0007] A split-type atomizer for ICP-MS includes: The main body shell has an axially extending inner cavity; A gas passage interface is provided on the main body shell and is used to connect to external high-purity gas; An air passage is provided inside the main body shell, communicates with the air passage interface, and extends to the front end of the main body shell; A central capillary tube is arranged axially along the main body shell in the inner cavity for transporting sample solution; Atomizing nozzle, which is detachably installed at the front end of the main body shell, and together with the air passage and the outlet of the central capillary, forms an atomizing zone; An inverted conical joint is disposed at the rear end of the main body shell and is used to fix and seal the central capillary tube; The main body shell is manufactured using a fused deposition modeling process, and the atomizing nozzle is formed using a photopolymerization process.

[0008] Furthermore, the material of the main body shell is polylactic acid; the minimum feature size of the nozzle of the atomizing head is 10 μm; the main body shell does not directly contact the sample solution, and the liquid interface of the sample solution is defined by the central capillary and the inverted conical connector.

[0009] Furthermore, the atomizing nozzle is provided with a nozzle structure, which is a Laval type nozzle; the atomizing nozzle and the main body shell are detachably connected by a threaded structure.

[0010] Furthermore, the central capillary is a PEEK capillary with an inner diameter of 25-500 μm and an outer diameter of 1 / 32 inch or 1 / 16 inch; the outlet end of the central capillary is coaxially arranged with the nozzle outlet end of the atomizing nozzle, and the outlet end of the central capillary is recessed inward by 0.1-0.5 mm relative to the nozzle outlet end of the atomizing nozzle.

[0011] Furthermore, the air passage interface is arranged in a direction perpendicular to or inclined to the axis of the main body shell; the air passage includes a vertical air intake section, a transition section, and a front acceleration section.

[0012] Furthermore, the inverted conical joint includes one or more of an inverted conical sealing surface, a clamping thread, a ferrule, or a sealing gasket, used for axial clamping, radial positioning, and liquid sealing of the central capillary.

[0013] Furthermore, the air passage forms an annular air gap near the atomizing nozzle, and the width of the annular air gap is 300-500μm.

[0014] Furthermore, the atomizing nozzle includes a replaceable nozzle core, and different nozzle cores have different nozzle orifice diameters, air gap widths, taper angles, outlet fillets, outlet chamfers, or inner surface roughness.

[0015] Furthermore, the atomizer also includes a detachable atomization chamber or observation chamber, which is connected to the main body shell or the atomizing nozzle, and is used to switch between particle size characterization mode and ICP-MS on-machine testing mode without changing the assembly reference of the central capillary and the atomizing nozzle.

[0016] Furthermore, under the operating conditions of atomizing gas flow rate of 0.5-2.0 L / min and sample flow rate of 0.01-0.1 mL / min, the volume fraction of droplets with a diameter of 1-15 μm in the volume distribution generated by the nebulizer is not less than 80%.

[0017] On the other hand, this application also claims protection for a method for manufacturing, assembling, and controlling the particle size of the aforementioned split-type atomizer, including the following steps: S1: Manufacture the main body shell and form an air passage interface and an air passage on the main body shell; S2: Manufacture an atomizing nozzle and form a nozzle structure in the atomizing nozzle; S3: Select the central capillary, cut it to the predetermined length, deburr it and clean it; S4: Insert the central capillary tube into the main body shell, and fix and seal it through the inverted conical joint; S5: Assemble the atomizing nozzle to the front end of the main body shell, so that the air passage, the outlet of the central capillary, and the atomizing nozzle together form an atomizing zone; S6: By adjusting the nozzle orifice diameter, air gap width, outlet position of the central capillary, atomizing gas flow rate, and sample flow rate, the droplet volume distribution is mainly concentrated in 1-15μm.

[0018] Furthermore, in step S2, a rounded corner or chamfer is provided at the nozzle outlet edge of the atomizing nozzle, with a rounded corner radius or chamfer size of 5-100μm.

[0019] Furthermore, in step S6, a laser particle size analyzer, high-speed camera, or transmission efficiency test method is used to provide feedback on the droplet size distribution and atomization stability, and the atomizing nozzle is iteratively screened based on Dv(10), Dv(50), Dv(90), Span, and 1-15μm volume fraction.

[0020] Compared with the prior art, the present invention achieves the following beneficial technical effects: This application's split-type nebulizer significantly reduces manufacturing costs and iteration cycles by detachably connecting the main shell and the atomizing nozzle using a partitioned additive manufacturing process. Simultaneously, high-precision manufacturing is concentrated in the nozzle area, improving yield and assembly consistency. A central capillary fixed with an inverted conical connector defines the liquid interface, reducing sample corrosion and memory effects. The replaceable atomizing nozzle facilitates cleaning and maintenance and supports systematic screening of nozzle geometry parameters using a single variable. The synergistically optimized gas path and nozzle structure produce narrow-distribution fine droplets, effectively improving sample introduction efficiency and the stability of ICP-MS analysis signals. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a split-type atomizer for ICP-MS according to the present invention.

[0023] Figure 2 This is a graph showing the droplet size distribution of the atomized liquid generated using the atomizer in an embodiment of the present invention.

[0024] In the diagram: 1-Main body shell; 11-Air path interface; 12-Air path channel; 2-Atomizing nozzle; 21-Nozzle structure; 3-Atomizing zone; 4-Central capillary; 5-Inverted conical connector. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In one embodiment of this application, a split-type atomizer for ICP-MS is provided. Please refer to... Figure 1The core of this nebulizer lies in its modular "three-part" design, consisting of a main shell 1, a detachable atomizing nozzle 2, and a central capillary 4 independently fixed by an inverted conical connector 5. Specifically, the main shell 1 serves as the structural framework and assembly reference for the entire nebulizer. It is an axially extending cylindrical structure with an axially extending internal cavity for housing and positioning the central capillary 4. The main shell 1 has an air passage interface 11 for connecting to an external high-pressure gas source; this interface can be a standard pneumatic quick-connect fitting or a threaded pagoda connector. An air passage 12 is also provided inside the main shell 1. This air passage 12 starts from the root of the air passage interface 11, extends into the interior of the main shell 1, and finally leads to the front end of the main shell 1, guiding external gas to the atomization area. The central capillary 4, serving as the sample solution delivery channel, is arranged along the axial direction of the main shell 1 within its internal cavity. The atomizing nozzle 2 is an independent, detachable component mounted on the front end of the main body shell 1. Once installed, its internal space, together with the outlet of the gas passage 12 and the front outlet of the central capillary tube 4, forms an atomization zone 3. Here, high-speed gas interacts with the liquid sample to complete atomization. At the rear end of the main body shell 1, an inverted conical connector 5 is provided. This connector 5, through a structure such as a clamping nut and a ferrule, firmly fixes and seals the central capillary tube 4 within the inner cavity of the main body shell 1, ensuring precise axial positioning and preventing leakage or shaking. Specifically, in this embodiment, the main body shell 1 is not manufactured using traditional machining or integrated 3D printing, but rather using fused deposition modeling (FDM). Meanwhile, the atomizing nozzle 2, which requires extremely high precision, is formed using a higher-resolution photopolymerization process (SLA / DLP). This strategy of differentiating different components and selecting different additive manufacturing processes is one of the key inventive points of this invention. It allows the atomizer to significantly reduce the manufacturing cost and iteration difficulty of the main body shell while ensuring the precision of key parts such as the nozzle.

[0027] In one embodiment of this application, to further optimize the performance and cost of the atomizer, the materials and processes for the main body shell 1 and the atomizing nozzle 2 are specifically defined. The main body shell 1 is manufactured using FDM technology, and its material is polylactic acid (PLA), which is an environmentally friendly material that is inexpensive, easy to print, and has a certain mechanical strength. Since the liquid sample flow path of the entire atomizer is completely confined inside the central capillary 4, the inner wall and internal structure of the main body shell 1 do not come into direct contact with the sample solution, so the selection of PLA material is safe and economical. For the atomizing nozzle 2, it is formed using a high-precision micro-nano photopolymerization process, so that the minimum feature size of the nozzle structure 21 can reach 10 micrometers, which is crucial for achieving a fine flow channel design and obtaining an ideal droplet size distribution. Through this design, the atomizer realizes the manufacturing concept of "high precision for critical parts and low cost for non-critical parts".

[0028] In one embodiment of this application, to enhance the atomization efficiency of the atomizer, particularly by increasing the relative velocity of the gas-liquid two-phase flow to obtain finer droplets, the nozzle structure 21 within the atomizing nozzle 2 is designed as a Laval-type nozzle. This Laval-type nozzle has a special geometry of contraction followed by expansion. When high-pressure gas flows through it, it reaches sonic speed at the throat and accelerates to supersonic speed in the expansion section, thereby generating extremely strong shear force to efficiently break the liquid sample into micron-sized aerosols. Simultaneously, to achieve convenient, stable, and repeatable assembly and disassembly between the atomizing nozzle 2 and the main housing 1, a precision threaded connection is used. This threaded connection not only ensures the coaxiality and airtightness of the connection but also allows operators to replace the atomizing nozzle 2 by hand without any special tools, greatly facilitating subsequent parameter selection and routine maintenance.

[0029] In one embodiment of this application, the material selection, specifications, and installation position of the central capillary 4 are meticulously designed. The central capillary 4 is made of PEEK (polyetheretherketone), a special engineering plastic with excellent chemical inertness, high-temperature resistance, and mechanical strength. It can withstand almost all common chemical reagents, including high-concentration acids, alkalis, and organic solvents, ensuring the reliability of analysis on complex matrix samples. Its inner diameter can be selected between 25 micrometers and 500 micrometers according to the sample flow rate requirements, while its outer diameter is standardized to 1 / 32 inch or 1 / 16 inch for compatibility with common chromatographic connectors and inverted conical connectors 5. During assembly, the outlet end of the central capillary 4 is strictly coaxially arranged with the nozzle outlet end of the atomizing nozzle 2. Furthermore, the outlet end of the central capillary 4 is not protruding or flush with the nozzle outlet end, but rather recessed inwards relative to the nozzle outlet end, i.e., it is arranged in a "recessed" manner. Extensive experiments have shown that when the indentation distance is precisely controlled within the range of 0.1 mm to 0.5 mm, the Venturi negative pressure generated by the Laval nozzle can most stably draw the liquid out of the indented capillary and form a stable liquid cone at the nozzle plane. At the same time, the indentation structure can effectively protect the liquid cone from interference from external airflow, thereby obtaining the most stable and finest atomization effect.

[0030] In one embodiment of this application, the specific layout and structure of the air passage are optimized. The air passage interface 11 is not arranged along the axial direction, but is arranged on the side of the main body shell 1, and its axis can be perpendicular to or inclined to the axis of the main body shell 1. This side air intake method can shorten the distance between the external air supply pipeline and the atomizer, making the structure more compact. Accordingly, the air passage 12 located inside the main body shell 1 is designed as a three-section structure with distinct functions: first, a vertical air intake section that is directly connected to the air passage interface 11; then, a transition section connecting the vertical air intake section and the front end structure, which adopts large rounded corners or smooth curved surfaces to reduce airflow eddies and pressure loss; and finally, an acceleration section located at the front end, which is usually a ring-shaped tapering structure, used to accelerate the gas and guide it to the atomizing nozzle 2.

[0031] In one embodiment of this application, the specific configuration of the inverted tapered joint 5 is defined. The inverted tapered joint 5 is an assembly integrating fixing, sealing, and positioning functions, and specifically may include a clamping nut with a chamfered sealing surface, a ferrule for gripping the capillary tube, and a sealing washer for auxiliary sealing. When the clamping nut is tightened, the chamfered sealing surface compresses the ferrule and the sealing washer, causing them to contract radially, thereby tightly gripping the outer wall of the central capillary tube 4. This structure can simultaneously apply axial clamping force to the central capillary tube 4, accurately position it radially, and achieve a highly airtight liquid-tight seal, ensuring that the position of the capillary tube does not change after long-term use or multiple disassembly and assembly.

[0032] In one embodiment of this application, the width of the annular air gap—a key geometric parameter affecting atomization efficiency—was specifically optimized. In the acceleration section at the front end of the gas path channel 12, an annular gap, i.e., the annular air gap, is formed near the atomizing nozzle 2, surrounding the central capillary 4. The width of this annular air gap is a core parameter determining the gas jet velocity and shear force. Through extensive theoretical calculations and experimental verification, this embodiment preferably controls the width of the annular air gap within the range of 300 to 500 micrometers. At this width, the gas can achieve a sufficiently high linear velocity to break up the liquid, while avoiding excessive back pressure or easy clogging due to an overly narrow air gap.

[0033] In one embodiment of this application, to further enhance the atomizer's adaptability to different application scenarios, the atomizing nozzle 2 is designed as an assembly containing a replaceable nozzle core. This means that operators can change key geometric parameters such as nozzle orifice diameter, air gap width, taper angle, outlet radius, outlet chamfer, or inner surface roughness simply by replacing the internal nozzle core, without replacing the entire atomizing nozzle housing. This design makes conducting detailed atomization mechanism studies or optimizing atomization conditions for specific samples more economical and efficient.

[0034] In one embodiment of this application, the atomizer is further configured with a detachable atomizing chamber or a transparent observation chamber. This atomizing chamber or observation chamber can be connected to the main housing 1 or the atomizing nozzle 2 via a quick-connect interface. When connected to the observation chamber and used in conjunction with a high-speed camera system, the atomizer can be easily switched to "particle size characterization mode" to study the atomization morphology and droplet breakup process under different parameters. When switching to "ICP-MS on-machine testing mode," simply remove the observation chamber and connect the atomizer directly to the atomizing chamber interface of the ICP-MS. More importantly, since the assembly reference of the central capillary 4 and the atomizing nozzle 2 remains unchanged throughout the switching process, the atomization performance data obtained in the two modes are highly comparable, which is crucial for systematically optimizing atomizer performance.

[0035] In one embodiment of this application, by employing all the aforementioned optimized designs, particularly the combination of the Laval nozzle, the recessed capillary, and the 300-500 micrometer annular air gap, this nebulizer exhibits superior nebulization performance under typical ICP-MS operating conditions. Specifically, when the nebulizing gas flow rate (e.g., high-purity argon) is set at 0.5 to 2.0 L / min and the sample solution flow rate is set at 0.01 to 0.1 mL / min, the aerosol generated is measured using a laser particle size analyzer. The results show that the volume fraction of droplets with a diameter of 1 to 15 micrometers within the "efficient transport window" is not less than 80%. Under more optimized conditions, this proportion can even exceed 90%. This means that the nebulizer of this invention can convert the vast majority of the sample into fine droplets that can be effectively utilized by ICP-MS, thereby significantly improving analytical sensitivity and stability, and reducing matrix effects and interface cone contamination.

[0036] In one embodiment of this application, a method for manufacturing, assembling, and controlling the aforementioned split-type atomizer is also provided. This method is a closed-loop, iterative process. Specifically, it includes the following steps: In step S1, the main body shell 1 is first manufactured using fused deposition modeling (FDM) based on a pre-designed 3D model. During the printing process, the mounting base for the air passage interface 11, the complete air passage channel 12, and the threaded or snap-fit ​​structures for connecting other components need to be precisely formed. After printing, the air passage channel 12 needs to be purged to remove internal support material and debris.

[0037] In step S2, a high-precision stereolithography (SLA / DLP) 3D printing process is used to manufacture the atomizing nozzle 2. During the printing process, fine features such as the Laval nozzle and annular air gap must be precisely formed. After printing, the nozzle edge quality is inspected under a microscope and ultrasonic cleaning is performed.

[0038] In step S3, select a PEEK central capillary tube 4 of suitable length and inner diameter. Cut it to the designed length using a special cutter, and then deburr the end face of the tube with fine sandpaper to ensure a smooth end face. Finally, perform ultrasonic cleaning in isopropanol and deionized water in sequence, and then dry it for later use.

[0039] In step S4, the processed central capillary tube 4 is inserted through the rear end of the main body shell 1, with its front end extending beyond the front end face of the main body shell 1. Then, the various components of the inverted conical joint 5 are sequentially fitted onto the central capillary tube 4, and with the assistance of the positioning fixture, the central capillary tube 4 is pulled back to the predetermined recessed position. Finally, the clamping nut of the inverted conical joint 5 is tightened to securely fix and seal the central capillary tube 4.

[0040] In step S5, the manufactured atomizing nozzle 2 is precisely installed onto the front end of the main body shell 1 by screwing it in, ensuring that the positioning surfaces of the two fit tightly together, so that the air passage 12, the outlet of the central capillary tube 4 and the atomizing nozzle 2 together form a complete atomization zone 3.

[0041] In step S6, the assembled nebulizer is connected to the gas source and liquid system, and the nebulizing gas and sample liquid flow are started. Then, by adjusting a series of key parameters, such as replacing the nebulizer nozzle 2 with one of different nozzle diameters, fine-tuning the indentation of the central capillary 4 through the inverted conical connector 5, and adjusting the nebulizing gas flow rate or sample solution flow rate, the ultimate goal is to concentrate the generated droplet volume distribution mainly within the 1 to 15 micrometer range, which is most favorable for ICP-MS analysis.

[0042] In one embodiment of this application, step S2 of the above method is further optimized. Specifically, when designing and manufacturing the three-dimensional model of the atomizing nozzle 2, a small rounded or chamfered feature is intentionally provided at the edge of its nozzle outlet. The radius or size of this rounded or chamfered feature is controlled within the range of 5 micrometers to 100 micrometers. The purpose of this is to eliminate tiny burrs or stress concentration points generated at the nozzle edge due to processing or long-term use, as these tiny defects are common causes of atomized jet deflection, the generation of undesirable large satellite droplets, and atomization instability. By increasing this rounded or chamfered feature, the atomizer can achieve a more stable and uniform atomization cone angle and droplet distribution.

[0043] In one embodiment of this application, step S6 of the above method is further defined to form a closed-loop feedback control system. Specifically, when adjusting the atomization performance, a laser particle size analyzer can be used to measure the droplet size distribution in real time, or a high-speed camera system can be used to directly observe the droplet breakup morphology in the atomization zone. These real-time acquired test data (such as Dv(10), Dv(50), Dv(90), Span value, and 1-15 micrometer volume fraction) are used as feedback signals. Based on these feedback signals, the operator determines whether the current atomization performance has reached the preset target. If not, based on the feedback information, it is determined whether to replace the atomizing nozzle 2 with a different parameter (e.g., a smaller nozzle orifice diameter or a narrower air gap), or to fine-tune the capillary indentation, or to optimize the gas-liquid flow rate. Through this "test-feedback-screening-iteration" cyclic process, the optimal atomizing nozzle 2 structure and optimal operating parameters for a specific application can be efficiently screened.

[0044] Example: Particle size testing To verify the actual effect of the atomizer of this invention, we manufactured a specific atomizer prototype according to the above-described embodiments and conducted particle size distribution tests on it. In this prototype, a Laval-type nozzle was used, with an annular air gap width of 400 micrometers. The central capillary 4 was made of PEEK material with an inner diameter of 100 micrometers, and the indentation distance between its outlet end and the nozzle outlet end was 0.3 millimeters. The test conditions were: the atomizing gas was high-purity nitrogen (for laboratory characterization), with a stable flow rate of 1.2 liters / minute; the sample was deionized water, delivered via a syringe pump at a constant flow rate of 0.05 milliliters / minute. The testing instrument used was a Spraytec laser particle size analyzer equipped with a 300-millimeter lens and an optical path of 20.0 millimeters, measured in Open Spray mode. The measurement results are as follows: Figure 2 As shown in the table below, the median diameter Dv(50) of the droplet volume distribution is 5.37 μm, and Dv(90) is 10.12 μm, with a volume fraction of 97.54% of the droplets having a diameter in the range of 1 to 15 μm. This result fully demonstrates that the technical solution of the present invention can stably produce aerosols with concentrated and fine particle sizes, which are very suitable for ICP-MS analysis, and greatly improves the sample transport efficiency and utilization.

[0045] Table 1. Main instrument parameters and statistical results for particle size testing

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A split-type atomizer for ICP-MS, characterized in that, include: The main body shell (1) has an axially extending inner cavity; Gas interface (11), the gas interface (11) is disposed on the main body shell (1) and is used to connect to external high-purity gas; Air passage (12), the air passage (12) is disposed inside the main body shell (1), communicates with the air passage interface (11), and extends to the front end of the main body shell (1); A central capillary tube (4) is arranged in the inner cavity along the axial direction of the main body shell (1) for transporting sample solution; Atomizing nozzle (2) is detachably installed at the front end of the main body shell (1) and forms an atomizing zone (3) together with the air passage (12) and the outlet of the central capillary (4). A tapered connector (5) is provided at the rear end of the main body shell (1) for fixing and sealing the central capillary tube (4). The main body shell (1) is manufactured using a fused deposition modeling process, and the atomizing nozzle (2) is formed using a photopolymerization process.

2. The split-type atomizer according to claim 1, characterized in that: The material of the main shell (1) is polylactic acid; the minimum feature size of the nozzle (2) is 10 μm; the main shell (1) does not directly contact the sample solution, and the liquid interface of the sample solution is defined by the central capillary (4) and the inverted conical connector (5).

3. The split-type atomizer according to claim 1, characterized in that: The atomizing nozzle (2) is provided with a nozzle structure (21), which is a Laval type nozzle; the atomizing nozzle (2) and the main body shell (1) are detachably connected by a threaded structure.

4. The split-type atomizer according to claim 1, characterized in that: The central capillary (4) is a PEEK capillary with an inner diameter of 25-500 μm and an outer diameter of 1 / 32 inch or 1 / 16 inch. The outlet end of the central capillary (4) is coaxially arranged with the nozzle outlet end of the atomizing nozzle (2), and the outlet end of the central capillary (4) is recessed inward by 0.1-0.5 mm relative to the nozzle outlet end of the atomizing nozzle (2).

5. The split-type atomizer according to claim 1, characterized in that: The air passage interface (11) is arranged in a direction perpendicular to or inclined to the axis of the main body shell (1); the air passage (12) includes a vertical air intake section, a transition section and a front acceleration section.

6. The split-type atomizer according to claim 1, characterized in that: The inverted cone joint (5) includes one or more of an inverted cone sealing surface, a clamping thread, a ferrule, or a sealing gasket, and is used to axially clamp, radially position, and liquid-tightly seal the central capillary (4).

7. The split-type atomizer according to claim 1, characterized in that: The air passage (12) forms an annular air gap near the atomizing nozzle (2), and the width of the annular air gap is 300-500 μm.

8. The split-type atomizer according to claim 1, characterized in that: The atomizing nozzle (2) includes a replaceable nozzle core, and different nozzle cores have different nozzle diameters, air gap widths, taper angles, outlet fillets, outlet chamfers or inner surface roughness.

9. The split-type atomizer according to claim 1, characterized in that: The atomizer also includes a detachable atomizing chamber or observation chamber, which is connected to the main body shell (1) or the atomizing nozzle (2) to switch between particle size characterization mode and ICP-MS on-machine test mode without changing the assembly reference of the central capillary (4) and the atomizing nozzle (2).

10. The split-type atomizer according to claim 1, characterized in that: Under the operating conditions of 0.5-2.0 L / min atomizing gas flow rate and 0.01-0.1 mL / min sample flow rate, the volume fraction of droplets with a diameter of 1-15 μm in the volume distribution generated by the nebulizer is not less than 80%.

11. A method for manufacturing, assembling, and particle size control of a split-type atomizer as described in any one of claims 1 to 10, characterized in that, Includes the following steps: S1: Manufacture the main body shell (1) and form an air passage (11) and an air passage (12) on the main body shell (1). S2: Manufacture an atomizing nozzle (2) and form a nozzle structure in the atomizing nozzle (2); S3: Select the central capillary (4), cut it to the predetermined length, deburr it and clean it; S4: Insert the central capillary tube (4) into the main body shell (1) and fix and seal it through the inverted conical joint (5); S5: Assemble the atomizing nozzle (2) to the front end of the main body shell (1) so that the air passage (12), the outlet of the central capillary (4) and the atomizing nozzle (2) together form the atomizing zone (3). S6: By adjusting the nozzle orifice diameter, air gap width, outlet position of the central capillary (4), atomizing gas flow rate and sample flow rate, the droplet volume distribution is mainly concentrated in 1-15 μm.

12. The method according to claim 11, characterized in that: In step S2, a rounded corner or chamfer is provided at the nozzle outlet edge of the atomizing nozzle (2), with a rounded corner radius or chamfer size of 5-100 μm.

13. The method according to claim 11, characterized in that: In step S6, a laser particle size analyzer, high-speed camera or transmission efficiency test is used to provide feedback on droplet size distribution and atomization stability, and the atomizing nozzle (2) is iteratively screened based on Dv(10), Dv(50), Dv(90), Span and 1-15 μm volume fraction.

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