Inductively coupled plasma mass spectrometry denudation pool for laser denudation

Abstract

The technical scheme of the invention discloses a denudation pool for laser denudation and inductively coupled plasma mass spectrometry, and relates to the field of LA-ICP-MS aerosol collection devices. The device comprises a base, a denudation pool body, a sample bearing assembly, an in-situ gas circuit assembly, a denudation laser assembly and a pressure control module, a driving module is arranged in the base, an ultrathin CaFglass window layer is embedded in the top of the denudation pool body, a polytetrafluoroethylene coating is sprayed on the inner wall of the denudation pool body, the sample bearing assembly comprises a three-dimensional fine adjustment sample table and a magnetic suction type sample frame, the in-situ gas circuit assembly adjusts the distance between a gas inlet pipe and a gas outlet pipe (1-4 mm) through double mechanical arms, and a focusing objective lens is coaxial with a conical collection opening of the gas outlet pipe. The pressure control module maintains micro-positive pressure in the cell. According to the denudation pool, the problems of aerosol retention and insufficient sensitivity of a traditional denudation pool can be solved, the aerosol washing time is shortened to about 0.6 s, and the multi-element signal intensity is improved by 2-7 times.

Description

Technical Field

[0001] This invention relates to the field of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and particularly to an aerosol collection and transmission device for high spatial resolution elemental analysis in a LA-ICP-MS system. Background Technology

[0002] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is widely used in micro-area elemental analysis and imaging, especially suitable for samples with fine structures or small volumes, such as geological samples and biological tissues. In this system, high spatial resolution elemental imaging places special requirements on aerosol acquisition and transmission devices, which is closely related to the core objectives and application scenarios of this technology. Specifically, it is reflected in: (1) revealing sample heterogeneity: for example, inclusions in geological minerals, impurity diffusion layers in semiconductor materials, and element-enriched regions in biological tissues, which require high-resolution imaging to observe the microscopic distribution patterns of elements. (2) locating trace elements: for elements with extremely low content (such as below ppm), high spatial resolution can avoid signal masking caused by macroscopic average detection and accurately capture local enrichment phenomena.

[0003] Laser ablation of samples generates aerosol particles (including ablation products), which must be transported to the mass spectrometer via a transmission device. Improper handling during transmission can directly reduce spatial resolution for the following reasons: If the aerosol mixes or diffuses within the transmission channel, particles ablated at different locations will interfere with each other, causing the mass spectrometry signal to fail to correspond to the original sample position, resulting in a "blurred" imaging result. For example, when the laser spot diameter is 5 μm, if the particle diffusion range in the transmission channel reaches 10 μm, the imaging resolution will decrease from 5 μm to 10 μm or even lower. Furthermore, larger aerosol particles may deposit due to gravity or adsorption on the inner wall of the channel, leading to particle size fractionation (larger particles suffer greater loss), which in turn causes elemental composition deviations (e.g., high-melting-point element particles are more likely to deposit), affecting the accuracy of imaging.

[0004] In the current field of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), improvements to the ablation cell revolve around "shortening elution time and optimizing spatial repeatability." The mainstream technical directions and limitations are as follows: Dual-volume ablation cell technology: To reduce gas flow diffusion, existing technologies mostly adopt a dual-volume structure, which is divided into two categories according to the displacement stage layout. When the displacement stage is external, a small-volume ablation cell needs to be moved by a motor to achieve positioning. Although the local cavity is reduced, the uneven gas flow distribution leads to a significant spatial position effect, and the aerosol transport path within the cell is long, with an elution time as long as 10-20 seconds. When the displacement stage is internal, the overall volume of the ablation cell increases (usually >30mL), which not only increases the consumption of carrier gas (helium) by more than 50%, but also increases the risk of sample cross-contamination. In addition, the large-volume cavity is prone to aerosol diffusion, and the sensitivity is difficult to meet the requirements of trace element detection.

[0005] Rapid elution ablation pool technology (such as CN202411984949.X): By shortening the airflow transmission distance through "air inlet channel surrounding sample outlet", the elution time is optimized to 5-8s, and the spatial repeatability RSD is reduced to 8-10%. However, there are still limitations. The structure of "fixed coaxial sample outlet + air blowing tube" is adopted, and the volume of the local cavity (inside the sample outlet) is still relatively large (diameter > 3mm). Aerosols are prone to secondary diffusion inside the tube. Moreover, no structure is designed to adapt to the aerosol extraction efficiency. Large aerosol particles are prone to deposit on the tube wall, resulting in limited improvement in sensitivity (multi-element signal intensity is only increased by 1-2 times), making it difficult to adapt to trace element detection in small spot (5-10μm) ablation scenarios.

[0006] To address the core pain points of existing technologies, namely "excessive diffusion due to large local volume, low aerosol extraction efficiency, and insufficient sensitivity," this application aims to solve the following technical problems: 1. Solve the aerosol diffusion problem caused by excessively large local cavity volume in existing ablation tanks (e.g., sample outlet diameter > 3mm), achieving "extraction upon generation" of aerosols and further shortening the washing time to less than 1 second; 2. Solve the problem of low aerosol extraction efficiency in existing fixed gas path structures, reducing the deposition of large aerosol particles and improving the signal intensity of multiple elements (especially the poorly ionized elements Be, P, and S); 3. Solve the problem of insufficient sensitivity in existing technologies when ablated small spots (5-10μm), ensuring the detection requirements of trace elements (ppm level), while also considering carrier gas consumption and spatial repeatability. Summary of the Invention

[0007] The objective of this invention is to improve the transport efficiency of aerosol particles generated by laser ablation by designing an in-situ extraction ablation cell. Furthermore, it enhances the sensitivity of LA-ICP-MS for elemental analysis and reduces elemental fractionation effects, offering the following benefits:

[0008] 1) Compared with the traditional cylindrical erosion pool, the designed in-situ extraction erosion pool has a smooth erosion signal peak without tailing, and the aerosol washing time is shortened from 28 s to 0.6 s.

[0009] 2) Compared with the traditional cylindrical ablation cell, the designed in-situ extraction ablation cell improves the signal intensity of different elements by 2-7 times, especially for poorly ionized elements (such as Be, P, S, etc.).

[0010] 3) Aerosol deposition around the erosion pit is significantly reduced, the number of large particles on the aerosol collection filter membrane is reduced, the average aerosol particle size is smaller, and the particle size distribution range is narrower, which can effectively reduce the element fractionation effect and improve the accuracy of element quantification.

[0011] This application claims an in-situ extraction ablation cell for laser ablation inductively coupled plasma mass spectrometry, characterized by comprising: a base, wherein a driving module is disposed within the base; an ablation cell body, wherein the ablation cell body is fixed to the base, an ultrathin CaF2 glass window layer is fitted on the top, and a polytetrafluoroethylene coating is sprayed on the inner wall; a sample carrying assembly, including a three-dimensional fine-tuning sample stage connected to the driving module, and a magnetic sample holder disposed on the sample stage via ball bearings; an in-situ gas path assembly, including a stainless steel inlet pipe, a stainless steel outlet pipe with a conical collection port at the end, and a dual robotic arm adjustment structure connecting the two gas pipes respectively, wherein the dual robotic arms can adjust the distance between the two gas pipes to 1-4 mm; an ablation laser assembly, including a laser generator and a focusing objective, wherein the focusing objective is disposed above the ablation cell body and coaxial with the conical collection port of the stainless steel outlet pipe; and a pressure control module, including a pressure sensor disposed in the ablation cell body, and an auxiliary inlet valve connected to the sensor.

[0012] Furthermore, the ultra-thin CaF2 glass window layer has a thickness of 0.3 mm and a light transmittance of ≥95%.

[0013] Furthermore, the positioning accuracy of the three-dimensional fine-tuning sample stage is 0.1 μm, and the positioning error of the drive module is ≤0.5 μm.

[0014] Furthermore, the inner diameter of the stainless steel inlet pipe and outlet pipe is 1-2 mm, the taper of the conical collection port is 30°-45° and the diameter is 0.5-1 mm, and the distance between the conical collection port and the sample surface is 1-2 mm during operation.

[0015] Furthermore, the dual robotic arms have a movement accuracy of 0.1mm and a movement range of ±5mm along the X / Y axes.

[0016] Furthermore, the pressure control module maintains the pressure in the erosion tank at 0.105-0.11 MPa, the auxiliary air inlet valve introduces pure helium, and the air inlet pipe introduces a helium-argon mixed carrier gas (volume ratio 9:1).

[0017] This application specifically addresses three core issues in aerosol transport and detection using traditional LA-ICP-MS ablation cells:

[0018] 1. Traditional cylindrical ablation tanks (volume > 30 mL) have many airflow vortices and long transport paths, resulting in severe aerosol diffusion and a washing time of up to 28 ± 4 s. This application eliminates airflow vortices and solves the problem of aerosol retention in the tank by using a small-volume cavity and in-situ acquisition design.

[0019] 2. Traditional ablation tanks have fixed gas paths and strong adsorption on the inner wall, making it easy for large aerosol particles to deposit. In particular, the signals of poorly ionized elements (Be, P, S) are weak and element fractionation is significant. This application solves the problems of low sensitivity and fractionation effect by using adjustable gas paths, polytetrafluoroethylene coating, and small-particle aerosol control.

[0020] 3. Traditional ablation pools cannot accurately match the micro-area acquisition requirements of 5-10μm small spot ablation, resulting in a decrease in spatial resolution; this application solves the problems of difficult point alignment and low aerosol capture efficiency in small spot ablation by using a three-dimensional fine-tuning sample stage and a movable acquisition port. Attached Figure Description

[0021] This specification will further illustrate embodiments by way of exemplary models, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0022] Figure 1 This is a schematic diagram of the cross-sectional structure of the designed in-situ extraction and erosion pool.

[0023] Figure 2 This is a top view schematic diagram of the designed in-situ extraction and erosion pool.

[0024] Figure 3 The results are simulations of airflow within the erosion tank under different distances between the air inlet and outlet.

[0025] Figure 4 This is a comparison chart of the washing time between the designed in-situ extraction erosion tank and the traditional cylindrical erosion tank.

[0026] Figure 5 It is the enhancement factor of the erosion signal of the designed in-situ extraction erosion pool compared to the traditional cylindrical erosion pool.

[0027] Figure 6 These are micrographs of the erosion pits when the designed in-situ extraction erosion pool and the traditional cylindrical erosion pool eroded NIST610.

[0028] Figure 7 These are photographs of the aerosol collection filter membrane and scanning electron microscope images of the collected aerosol particles.

[0029] In the figure: 1-base, 2-etching tank, 3-calcium fluoride glass, 4-sample stage, 5-inlet pipe, 6-outlet pipe, 7-right robotic arm, 8-left robotic arm. Detailed Implementation

[0030] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. It should be understood that these exemplary embodiments are given merely to enable those skilled in the art to better understand and implement this specification, and are not intended to limit the scope of this specification in any way. Unless obvious from the linguistic context or otherwise, the same reference numerals in the figures represent the same structures or operations.

[0031] Improving washout time hinges on reducing aerosol diffusion within the ablation cell, while enhancing sensitivity depends on minimizing aerosol deposition losses, increasing aerosol transport efficiency, and utilizing smaller aerosol particles for more thorough ionization in plasma. Current mainstream ablation cells are closed, single-volume structures, where aerosol particles generated during ablation easily diffuse and deposit, affecting acquisition efficiency and signal response, thus limiting the application of high-resolution imaging.

[0032] Please refer to Figure 1 and Figure 2 The present invention provides an ablation cell for laser ablation inductively coupled plasma mass spectrometry, which mainly includes: an ablation cell base, an ablation cell body, a transparent window layer composed of ultrathin CaF2 glass, a sample carrying platform, a stainless steel inlet pipe with an inner diameter of 1 mm-2 mm, a stainless steel outlet pipe with an inner diameter of 1 mm-2 mm, and a robotic arm fixed to the inlet and outlet pipes. The extraction tube can be moved in three dimensions by extending and retracting the robotic arm up, down, left, and right.

[0033] The ablation tank (2) is placed on the base (1). Above the ablation tank is a transparent window layer (3) composed of ultra-thin CaF2 glass (0.3mm) that can effectively transmit laser light. The sample stage (4) is located inside the ablation tank (2) for placing the sample. The stainless steel inlet pipe (5) is used to introduce carrier gas. The stainless steel outlet pipe (6) is located above the sample stage (4) for aerosol particle transport. The right robotic arm (7) is used for three-dimensional movement of the stainless steel inlet pipe (5). The left robotic arm (8) is used for three-dimensional movement of the stainless steel outlet pipe (6).

[0034] Specifically, the ablation tank (2) has a circular or square cavity structure when viewed from above; the transparent window layer (3) is located at the top center of the ablation tank (2), adapts to the boundary of the tank, covers the key area at the top of the tank, and ensures that the laser can penetrate vertically to the sample stage below; the sample stage (4) is a small platform in the view from above, located in the center of the ablation tank (2), corresponding to the transparent window layer (3) above and below. The sample is placed on the surface of the sample stage (4), and its position can be adjusted by the base drive module to ensure that the point to be ablated is aligned with the transparent window layer directly below; the stainless steel air inlet pipe (5) is a pipe section located inside the ablation tank (2), which is long and thin, located on one side of the sample stage (4), with the pipe opening facing the sample stage. The direction of the tube is fixed by the right robotic arm (7) and can be moved to the side of the sample stage with the adjustment of the robotic arm; the stainless steel exhaust pipe (6): the section of the tube inside the erosion tank (2) can be seen from above. It is also a long and thin tube, located directly above the sample stage (4). The tube opening is facing the area to be eroded on the sample stage surface. The tube body is fixed by the left robotic arm (8) and can be moved directly above the sample stage with the robotic arm to accurately align with different erosion points; the left robotic arm (8) and the right robotic arm (7): the two are connected to different positions on the outside of the erosion tank (2) from above. The main body of the robotic arm is rod-shaped and the end is connected to the corresponding air pipe. The position of the inlet and outlet air pipes in the horizontal direction can be adjusted by the extension and retraction of the robotic arm.

[0035] The distance between the stainless steel inlet and outlet pipes is a key factor affecting the airflow movement within the ablative etching tank. Software simulations were used to compare the airflow distribution and velocity changes within the tank under different pipe spacing. The standard cylindrical ablative etching tank has a large internal cavity, resulting in slow airflow velocity and airflow vortices at the inlet and outlet. This causes aerosol retention within the tank cavity, affecting aerosol elution time. In contrast, the self-designed ablative etching tank exhibits more regular airflow within the cavity as the distance between the two metal pipes decreases, with increased airflow velocity at the extraction points. This facilitates rapid aerosol elution. (Reference) Figure 3 When the distance between the two metal tubes is 1-4 mm, the airflow diffuses outward less. It is preferable to set the distance between the two tubes to 1 mm so that the airflow passes through the extraction point quickly without diffusion outward.

[0036] Figure 3 shows the airflow simulation diagram of the ablation tank. The left column shows the overall airflow in the tank, the middle column shows the cross-sectional view of the airflow in the tank, and the right column shows the airflow velocity diagram in the tank. It contains 4 sub-figures, corresponding to different types or parameters of ablation tanks: (a) standard cylindrical ablation tank airflow simulation; (b) self-designed ablation tank airflow simulation, with a 4 mm gap between the two air pipes; (c) self-designed ablation tank airflow simulation, with a 2 mm gap between the two air pipes; (d) self-designed ablation tank airflow simulation, with a 1 mm gap between the two air pipes. According to the simulation results, Figure (a): the left column shows that the airflow in the standard cylindrical ablation tank is irregularly diffused, with obvious airflow vortex areas; the cross-sectional view in the middle column shows that the airflow is unevenly distributed in the tank, with slow flow velocity near the tank wall and airflow stagnation in the central area; the velocity diagram in the right column shows that the overall flow velocity in the tank is low, and the velocity distribution varies greatly. The high velocity area is only concentrated near the air inlet, which cannot effectively cover the sample ablation area and easily leads to aerosol stagnation in the tank. Figure (b): The left column shows that the airflow has a directional flow trend in the cell, the diffusion range is reduced, and there are no obvious large-scale vortices; the cross-sectional view in the middle column shows that the airflow converges towards the outlet pipe after flowing out of the inlet pipe, and the flow path is relatively regular; the velocity diagram in the right column shows that the overall flow velocity in the cell is increased, and the high velocity area covers the sample ablation area and the vicinity of the outlet pipe, and the airflow transmission efficiency is significantly improved compared with the standard cylindrical ablation cell. Figure (c): The left column shows that the airflow diffusion range is further reduced, and it flows almost in a straight line along the inlet pipe → sample ablation area → outlet pipe; the cross-sectional view in the middle column shows that the airflow convergence effect is more obvious, and the airflow forms a high velocity channel in the sample ablation area with no stagnation area; the velocity diagram in the right column shows that the high velocity area is more concentrated, and the velocity value is higher than that in sub-figure (b), and the airflow's ability to carry aerosols is enhanced. Figure (d) (Self-designed ablation tank airflow simulation, with a 1mm gap between the two air pipes): The left column shows that the airflow is strictly directional, with no diffusion, and flows precisely along the path from the inlet pipe to the outlet pipe; the cross-sectional view in the middle column shows that the airflow is close to the sample surface, and after flowing out of the inlet pipe, it directly carries the aerosol generated by the sample ablation into the outlet pipe, without any diffusion in the tank; the velocity diagram in the right column shows that the flow velocity in the tank reaches the highest and is evenly distributed. The high-velocity area completely covers the sample ablation point and the outlet pipe opening, providing optimal airflow conditions for the rapid washing out of aerosols.

[0037] Figure 4 contains two subplots, which are the U element signal intensity-time curves when NIST610 standard samples are etched by a single pulse in different etch pools. The horizontal axis represents time (seconds), and the vertical axis represents signal intensity (counts / second).

[0038] Figure (a) (U signal diagram during single-pulse ablation of NIST610 in the designed in-situ extraction ablation cell): The curve is sharp and single-peaked, with no signal tailing phenomenon; the signal rises rapidly from the start time to the peak value (the peak signal intensity is relatively high), and then drops rapidly to the baseline level; the washout time of the U element signal (FW0.01M, i.e. the time span corresponding to 1% peak signal) is calculated from the curve to be 0.604±0.06 seconds, indicating that the aerosol has no retention in the cell and can be quickly transmitted to the detection end.

[0039] Figure (b) (U signal diagram of single-pulse ablation of NIST610 in a conventional cylindrical ablation cell): The curve is in the shape of "broad peak + long tail"; after the signal rises to the peak value, it cannot drop quickly, but falls back slowly, and the tailing phenomenon is serious; the washing time is 28±4 seconds, which is much longer than the designed in-situ extraction ablation cell, indicating that the airflow in the conventional ablation cell has a weak ability to carry aerosols, and aerosols are easy to diffuse and stay in the cell, resulting in signal tailing.

[0040] Figure 5 shows a bar chart, with the horizontal axis representing different elements to be detected (including Be, P, S, Cu, Pb, Zn, etc.) and the vertical axis representing the signal enhancement factor (i.e., the ratio of the signal intensity of the designed in-situ extraction ablation cell to the signal intensity of the traditional cylindrical ablation cell): For Be: the bar chart is the tallest, with a signal enhancement factor of 7 times, indicating that the designed ablation cell has the most significant signal enhancement effect on Be; For P and S: the bar chart is the second tallest, with a signal enhancement factor of 6-7 times, similar to Be, as poorly ionized elements, their signals are significantly enhanced in the designed ablation cell; For Cu, Pb, and Zn: the bar chart is relatively shorter, but the signal enhancement factor still reaches 2-5 times, with Cu showing a 5-fold enhancement and Pb and Zn showing a 4-fold enhancement. The signal intensity of conventional elements was also effectively enhanced. Overall trend: the designed in-situ extraction ablation cell showed better signal enhancement for poorly ionized elements (Be, P, S) than for conventional elements, and the signal intensity of all elements was higher than that of the traditional cylindrical ablation cell, which verified the advantages of the designed ablation cell in improving detection sensitivity.

[0041] Figure 6 contains six subfigures, showing optical microscope (OBM) and scanning electron microscope (SEM) images of the erosion pits generated after analyzing NIST610 standard samples in the designed in-situ extraction erosion pool and the traditional cylindrical erosion pool: Figure (a) (OBM image of erosion pits generated by NIST610 analysis in the designed in-situ extraction erosion pool): Under the optical microscope, the erosion pits are regularly circular with smooth edges, no obvious serrations or irregular protrusions, and no obvious residues inside. The diameter of the erosion pits matches the laser beam spot (60 μm) highly; Figure (b) (SEM image of erosion pits generated by NIST610 analysis in the designed in-situ extraction erosion pool): Under the SEM view, the bottom of the erosion pit is flat with no obvious depressions or protrusions, the pit walls are vertical, and there is no white layered material formed by aerosol deposition; Figure (c) (SEM image of the edge of the erosion pit, b) (Red box area in the image): After magnification, it can be seen that there is no accumulation of fine particles at the edge of the erosion pit, the edge lines are clear, and there is no "rough edge" phenomenon caused by aerosol gas phase redeposition; Figure (d) (Optical micrograph of erosion pit generated by NIST610 in a conventional cylindrical erosion pool): Under the optical microscope, the erosion pit is irregularly circular, the pit edge is rough, there are serrated protrusions, a small amount of white residue can be seen in the pit, the diameter of the erosion pit is slightly larger than the laser beam spot, and the morphological integrity is poor; Figure (e) (SEM image of erosion pit generated by NIST610 in a conventional cylindrical erosion pool): Under the SEM view, the bottom of the erosion pit is uneven, there are local depressions, the pit wall is tilted, and a large number of white sedimentary particles are attached to the pit and the pit wall, which are formed by the deposition of aerosols that were not effectively collected; Figure (f) (SEM image of the edge of the erosion pit, red box area in Figure e): After magnification, it can be seen that a large number of fine particles are accumulated at the edge of the erosion pit, the edge lines are blurred, there is obvious "rough edge" caused by aerosol gas phase redeposition, which seriously affects the morphological integrity of the erosion pit.

[0042] Figure 7 contains four sub-figures, showing photographs of aerosol collection filter membranes and SEM images of aerosol particles (including particle size distribution, not separately labeled, but implied in the SEM image analysis) after aerosol collection of NIST610 standard samples using a traditional cylindrical aerosol collection pool and a designed in-situ extraction aerosol collection pool: Figure (a) (aerosol collection filter membrane after aerosol collection of NIST610 using a traditional cylindrical aerosol collection pool): The filter membrane is circular (approximately 2-3 cm in diameter), with a wide coverage of contaminants on the surface. Besides the central area, significant aerosol particle residues are also present in the edge areas, accounting for approximately 60%-70% of the total filter membrane area. This indicates that the aerosol diffusion range in the traditional aerosol collection pool is large, making concentrated collection impossible; Figure (b) (aerosol collection of NIST610 using a designed in-situ extraction aerosol collection pool): (Afterwards, the aerosol collection filter membrane): The filter membrane is also circular, and the aerosol particles are only concentrated in the central area of ​​the filter membrane (about 1 cm in diameter). There are no obvious residues in the edge areas, and the residual area accounts for only 10%-20% of the total area of ​​the filter membrane. This indicates that the aerosol diffusion in the designed erosion pool is effectively suppressed, and centralized collection can be achieved; Figure (c) (morphology of aerosols generated by erosion in a traditional cylindrical erosion pool): Under the SEM view, the aerosol particles are irregular in shape, with a large number of blocky and flocculent aggregates. The particle size distribution range is wide (0.1-5 μm), with an average particle size of about 1.8 μm. Large particles (particle size > 2 μm) account for about 25%, which is not conducive to subsequent ICP-MS ionization; Figure (d) (morphology of aerosols generated by erosion in the designed in-situ extraction erosion pool): SEM From a visual perspective, aerosol particles are mainly spherical with no obvious aggregates. The particle size distribution range is narrow (0.1-1.5μm), with an average particle size of about 0.8μm. Large particles (particle size > 2μm) account for only 3%, while small particles account for a high proportion, making it easier to achieve complete ionization in ICP-MS and improve detection sensitivity.

[0043] Example 1: Comparison of Single-Pulse U Signals

[0044] To verify the effectiveness of the "in-situ adjustable gas path + small volume chamber" in this application, the U signal of the NIST610 standard was measured under the same conditions (energy density 6 J / cm², beam spot 60 μm, single pulse): In this application, the conical collection port of the gas outlet is precisely positioned 1-2 mm above the sample surface, and the distance between the two gas tubes is adjusted to 1 mm by the dual robotic arms. Combined with the small volume chamber (5-8 mL) and the anti-adsorption coating on the inner wall, the U signal peak is smooth without tailing (Figure 4a), and the elution time is 0.604±0.06 s. Traditional ablation chambers, due to their large chamber size and lack of in-situ collection, exhibit signal peak tailing (Figure 4b), and the elution time is 28±4 s. Therefore, this application solves the problem of traditional aerosol retention.

[0045] Example 2: Comparison of Multi-element Signal Intensities

[0046] To verify the effectiveness of the "anti-adsorption coating + mixed carrier gas" in this application, NIST610 multi-element signals were measured under the same conditions (energy density 6 J / cm², beam spot 60 μm, frequency 10 Hz): the anti-adsorption coating on the inner wall of this application reduces aerosol deposition, and the helium-argon mixed carrier gas protects elements that are difficult to ionize. The signals of Be, P, and S were increased by 5-7 times, and those of Cu, Pb, and Zn were increased by 2-5 times. Figure 5 Traditional ablation cells lack anti-adsorption design and use a single carrier gas, resulting in generally low signal strength. Therefore, this application solves the problem of insufficient sensitivity in traditional methods.

[0047] Example 3: Comparison of erosion pit morphology

[0048] To verify the effectiveness of the "pressure control + stable airflow" method in this application, NIST610 erosion pits were observed under the same conditions (energy density 6 J / cm², beam size 60 μm, frequency 10 Hz): The pressure control in this application maintained a slightly positive pressure within the pit, while the stable airflow prevented aerosol reverse deposition, resulting in smooth, residue-free edges on the erosion pits (Figures 6a-c). Traditional erosion pits lack pressure control, resulting in turbulent airflow and rough edges with deposits (Figures 6d-f). Therefore, this application solves the problem of reverse aerosol deposition in traditional methods.

[0049] Example 4: Comparison of Aerosol Properties

[0050] To verify the effectiveness of the "in-situ capture + airflow confinement" method in this application, aerosols were measured under the same conditions (energy density 6 J / cm², beam size 60 μm, frequency 10 Hz, 0.1 μm filter membrane): The aerosols in this application were precisely captured at the collection port, and the airflow confinement prevented agglomeration. The aerosol particles were small (average 0.8 μm) and narrowly distributed (Figures 7b and d), making them easily ionized. In contrast, aerosols in traditional ablation tanks diffused and agglomerated, resulting in large particles (average 1.8 μm) and a wide distribution (Figures 7a and 7c), making them difficult to ionize. Therefore, this application solves the problem of traditional aerosol fractionation.

[0051] This application addresses the challenges of aerosol acquisition and transport in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). It employs a comprehensive technical approach combining a compact chamber, an in-situ adjustable gas path, and precise control. The advantage lies in reducing aerosol particle deposition and dispersion through in-situ aerosol extraction, thereby achieving rapid aerosol extraction and improved sensitivity for elemental analysis. Structural design optimization includes a closed, small-volume ablation chamber (5-8 mL) with an inner wall coated with polytetrafluoroethylene (PTFE) to reduce aerosol adsorption. A 0.3 mm thick, ultra-thin CaF2 glass window with ≥95% transmittance is embedded at the top to ensure efficient laser penetration and compatibility with commonly used laser wavelengths such as 213 nm. In-situ adjustable gas path system: Equipped with stainless steel inlet / outlet pipes with an inner diameter of 1-2mm, the outlet pipe end has a tapered collection port with a taper of 30°-45° and a diameter of 0.5-1mm. Directional adjustment (X / Y axis ±5mm, accuracy 0.1mm) can be achieved via left / right dual robotic arms. Adjusting the distance between the inlet / outlet pipes (1-4mm) and the collection port position (1-2mm from the sample surface) enables "aerosol extraction upon generation." Precise drive and pressure control: The sample carrier uses a three-dimensional micro-adjustable sample stage with a positioning accuracy of 0.1μm, combined with a base-built-in drive module (positioning error ≤0.5μm), ensuring precise alignment of small spot erosion points. The erosion tank is equipped with a pressure sensor (accuracy ±0.001MPa) and an auxiliary inlet valve to maintain a slight positive pressure of 0.105-0.11MPa, preventing airflow vortices. Carrier gas and laser compatibility: Helium-argon mixed carrier gas (volume ratio 9:1, flow rate 500-800mL / min) is introduced through the inlet pipe, and pure helium gas (flow rate 100-200mL / min) is introduced through the auxiliary inlet; the laser component and the gas outlet are coaxially set (coaxiality error ≤0.1mm) to meet the requirements of 5-10μm small spot ablation.

[0052] This invention represents a breakthrough, offering simplicity and efficiency that can be rapidly deployed in solid micro-area analysis laboratories. Its advantages are as follows: 1. Significantly reduced elution time: When using single-pulse ablation of NIST610 standards, the aerosol elution time is reduced from the traditional 28±4s (FW0.01M) to 0.604±0.06s, with smooth peaks and no tailing, improving elution time stability (RSD≤5%), meeting the requirements for rapid micro-area imaging. 2. Significantly improved detection sensitivity: It exhibits a 2-7 fold increase in sensitivity for multi-element signal intensity, with the most significant increase (5-7 times) for poorly ionized elements (Be, P, S), and a 2-5 fold increase for common elements (Cu, Pb, Zn). It enables precise detection of ppm-level trace elements, solving the problem of insufficient sensitivity in traditional ablation pools for small-area spots. 3. Elemental Fractionation and Deposition Suppression: The average aerosol particle size is reduced from the traditional 1.8 μm to 0.8 μm, the particle size distribution range is narrowed from 0.1-5 μm to 0.1-1.5 μm, and the proportion of large particles (>2 μm) is reduced from 25% to 3%; the edges of the erosion pits are smooth (roughness <1 μm) with no obvious deposition, and the elemental fractionation coefficient is reduced by 60% (e.g., the fractionation coefficient of P element is reduced from 0.35 to 0.14), improving the accuracy of quantitative analysis (RSD≤3%). 4. Cost and Anti-Contamination Optimization: The small-volume chamber and efficient airflow design reduce helium consumption by 60% compared to traditional erosion tanks (from 800-1000 mL / min to 300-400 mL / min); the detachable and washable structure and low-adsorption coating reduce aerosol residue to below 0.01%, reducing cross-contamination and adapting to continuous testing of multiple samples.

[0053] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0054] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0055] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0056] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A laser ablation cell for inductively coupled plasma mass spectrometry (ICP-MS), characterized in that: The base contains a drive module; the ablation tank is fixed to the base, with an ultra-thin CaF2 glass window layer embedded on the top and a polytetrafluoroethylene coating sprayed on the inner wall. The sample carrying assembly includes a three-dimensional fine-tuning sample stage connected to the drive module, and a magnetic sample holder mounted on the sample stage via ball bearings; the in-situ gas path assembly includes a stainless steel inlet pipe, a stainless steel outlet pipe with a conical collection port at the end, and a dual-arm adjustment structure connecting the two gas pipes respectively, wherein the dual-arm can adjust the distance between the two gas pipes to 1-4 mm; the ablation laser assembly includes a laser generator and a focusing objective lens, wherein the focusing objective lens is located above the ablation tank and is coaxial with the conical collection port of the stainless steel outlet pipe; the pressure control module includes a pressure sensor located in the ablation tank and an auxiliary inlet valve connected to the sensor.

2. The erosion tank according to claim 1, characterized in that, The ultra-thin CaF2 glass window has a light transmittance of ≥95%.

3. The erosion tank according to claim 1, characterized in that, The positioning accuracy of the three-dimensional fine-tuning sample stage is 0.1 μm.

4. The erosion tank according to claim 1, characterized in that, The stainless steel inlet and outlet pipes have an inner diameter of 1-2 mm, the conical sampling port has a taper of 30°-45° and a diameter of 0.5-1 mm, and the distance between the port and the sample surface is 1-2 mm during operation.

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