A dynamic sealed sample cell for a laser ablation system

Abstract

The application discloses a dynamic sealing sample cell for a laser ablation system, which comprises a sample cell, a sample cell shell, a collection cup, an air inlet, an air outlet, a sample support and a sample cell base; the air inlet and the air outlet are arranged on the sample cell shell, and the sample support is arranged on the sample cell base; the collection cup is connected with the air outlet and fixed in the interior of the sample cell shell; the sample cell shell is a cover shell with an open lower end, the upper surface of the sample cell base is a smooth plane, and the lower end of the sample cell shell and the upper surface of the sample cell base are in slidable sealing contact. In addition to the sample, the collection cup and the small sample support lifting platform, no other articles exist, so that the influence of external pollution on the detection quality is greatly avoided, and the good sealing property reduces the uneven air flow distribution caused by the position effect in the sample cell, so that the detection signal sensitivity and stability are improved.

Description

Technical Field

[0001] This invention belongs to the field of laser ablation technology, and particularly relates to a dynamic sealed sample cell for a laser ablation system. Background Technology

[0002] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) uses a laser to emit a laser beam, which is then focused onto a specific area of ​​the sample using an objective lens. The energy of the pulsed laser is used to directly ablate the solid sample into tiny particles, which form an aerosol with a carrier gas. The particles are then ionized by an inductively coupled plasma (ICP) source and introduced into the mass spectrometer for elemental detection.

[0003] LA-ICP-MS consists of two parts: a laser ablation solid sample introduction system and an inductively coupled plasma mass spectrometer. Currently, the most common laser ablation sample introduction systems on the market consist of a laser, an optical path system, a field lens, and a sample cell. The sample cell is further composed of a sample cup (some with an XY motion mechanism), a sample holder, a moving platform, and a gas path.

[0004] In laser ablation plasma mass spectrometry (LA-1CP-MS), the sample to be analyzed is first placed in the sample cell. The sample aerosol generated during laser ablation of the sample surface is carried into the plasma mass spectrometer by a carrier gas for elemental and isotopic analysis. The sample cell, used for sample placement and laser ablation, is one of the main components affecting the analytical performance of LA-1CP-MS. Therefore, the design of the sample cell is crucial. Particles mix during transport from the ablation zone to the ICP, and different sample cell designs will have a significant impact on the elemental analysis signal intensity, signal stability, elemental fractionation, and sample preparation efficiency.

[0005] There are currently three common types of sample cells on the market, which can be found in [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 .

[0006] like Figure 1 As shown, the sample cell has only one outlet, corresponding to the inlet, horizontally extending through the side of the sample chamber. The moving platform is located below the sample cell and is completely isolated from it. The moving platform changes the position of the sample within the sample cell by moving the entire sample cell. This design is prone to generating eddies on the sides of the sample cell. Only aerosols in the middle of the sample cell and near the outlet are easily transported, while aerosols in many corner areas are not well transported, easily generating eddies, ultimately affecting the stability and accuracy of the analytical results. In addition, the limited number of samples that can be placed in the sample chamber leads to cumbersome and frequent sample changes, resulting in low work efficiency. Furthermore, the detection speed of this design is also very slow.

[0007] like Figure 2As shown, the sample cell employs dual air inlets on both sides, with several gas dispersion tubes added after the inlet pipes to improve the uniformity of the airflow. A sample holder is placed in the center of the sample cell, which can be moved in and out for loading or removing samples. Above the sample holder is a small sample cup, which is fixed in the sample cell via its XY axis. The position of the small cup can be moved by controlling the XY axis. An outlet pipe is connected to the side of the small cup, leading to the outside of the sample cell. The sample cell is placed on a main moving platform, which is completely isolated from the sample cell. The main moving platform moves the entire sample cell, thereby changing the position of the sample within it. The small cup moves in the opposite direction to the moving platform in the XY direction. Although the sample is centered in the atmosphere, positional effects still occur at different locations within the sample cell, resulting in uneven sample injection.

[0008] like Figure 3 As shown, the sample cell employs dual air inlets on both sides, with several gas dispersion tubes added after the inlet pipes to improve the uniformity of the airflow. A small cup is placed in the center of the sample cell and fixed inside. An inlet pipe connects to each side of the small cup, with the outlet located on the side of the cup. Below the small cup are the sample holder and the moving platform, both located inside the sample cell. The sample holder rests on the moving platform, allowing it to move in and out of the sample cell for loading or removing samples. By controlling the movement of the moving platform, the sample's position in the XY directions within the sample cell can be adjusted. This design ensures stable and uniform airflow within the sample cup, ultimately achieving stable mass spectrometry analysis signals. However, because the moving platform is located inside the sample cell, its mechanical components and lubricating oil are prone to contamination, interfering with the final detection results.

[0009] In summary, the existing sample cell design has the following main problems:

[0010] 1. Uneven airflow can occur at different locations in the sample cell, affecting the stability of the analytical signal;

[0011] 2. The mechanical devices and lubricating oil of the mobile platform can easily cause contamination, interfering with the final test results;

[0012] 3. The lack of flexibility in the sample cell leads to slow detection speed and low detection efficiency. Summary of the Invention

[0013] In view of this, one of the objectives of the present invention is to provide a dynamically sealed sample cell for a laser ablation system. Apart from the sample, the collection cup, and the sealed small sample holder lifting platform, there are no other items, which greatly avoids the impact of external contamination on the detection quality. Furthermore, the better sealing performance reduces the uneven airflow distribution caused by the position effect within the sample cell, thereby improving the sensitivity and stability of the detection signal.

[0014] To achieve the above objectives, the first aspect of the present invention provides a dynamically sealed sample cell for a laser ablation system, comprising: a sample cell housing, a collection cup, an air inlet, an air outlet, a sample holder, and a sample cell base.

[0015] The air inlet and air outlet are provided on the sample cell shell, and the sample holder is provided on the sample cell base;

[0016] The collection cup and the air outlet are connected and fixed inside the sample cell housing;

[0017] The sample cell housing is a cover-shaped structure with an opening at one end. The upper surface of the sample cell base is a smooth plane. The lower end of the sample cell housing and the upper surface of the sample cell base are in slidable, sealed contact.

[0018] Preferably, the sample cell housing is a glass cylinder with an opening at the bottom and smooth edges, and the sample cell base is a glass with a flat and smooth surface.

[0019] Preferably, it also includes a sample holder lifting platform, which includes a sample platform, a lifting assembly and a sealing assembly, and the sample holder lifting platform is mounted on the sample pool base;

[0020] The upper end of the lifting assembly is connected to the lower end of the sample platform;

[0021] The sealing assembly is located outside the lifting assembly. The upper end of the sealing assembly is connected to the lower end of the sample platform, and the lower end of the sealing assembly is connected to the upper surface of the sample pool base.

[0022] Preferably, the sealing component is a bellows.

[0023] Preferably, it also includes a mobile platform, which is disposed at the lower end of the sample pool base.

[0024] Preferably, the mobile platform is a high-precision three-axis mobile platform.

[0025] Preferably, the sample cell shell has multiple evenly distributed air inlets on both sides.

[0026] The beneficial effects of this invention are:

[0027] (1) Apart from the sample, the collection cup and the sealed small sample holder lifting platform, there are no other items in this invention, which greatly avoids the impact of external contamination on the detection quality. In addition, the good sealing performance reduces the uneven airflow distribution caused by the position effect in the sample cell, thereby improving the sensitivity and stability of the detection signal.

[0028] (2) The present invention greatly reduces the sample cell volume, reduces the amount of carrier gas used, reduces the cost of a single analysis, increases the detection speed, and can also detect multiple samples at the same time. Attached Figure Description

[0029] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figures 1 to 3 This is a schematic diagram of a sealed sample cell in the prior art;

[0031] Figure 4 This is a schematic diagram of the structure of the dynamically sealed sample cell disclosed in the embodiments of the present invention;

[0032] 1 Sample; 2 Sample holder; 3 Moving platform; 4 Laser; 5 Objective lens; 6 Sample cell housing; 7 Sample cell base; 8 Sample holder lifting platform; 9 Sealing assembly; 10 Collection cup. Detailed Implementation

[0033] One of the core aspects of this invention is to provide a dynamic sealed sample cell for a laser ablation system. The sample cell contains no other items besides the sample, the collection cup, and the sealed small sample holder lifting platform. This greatly avoids external contamination affecting the detection quality. Furthermore, the good sealing performance reduces the uneven airflow distribution caused by positional effects within the sample cell, thereby improving the sensitivity and stability of the detection signal.

[0034] 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, and 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.

[0035] from Figure 4As shown, the dynamic sealed sample cell for a laser ablation system disclosed in this embodiment includes a sample cell housing 6, a collection cup 10, an air inlet, an air outlet, a sample holder 2, and a sample cell base 7. The air inlet and air outlet are disposed on the sample cell housing 6, and the sample holder 2 is disposed on the sample cell base 7. The collection cup 10 and the air outlet are connected and fixed inside the sample cell housing 6. The sample cell housing 6 is an outer shell shape with an opening at the lower end, and the upper surface of the sample cell base 7 is a smooth plane. The lower end of the sample cell housing 6 and the upper surface of the sample cell base 7 are in slidable sealed contact. The moving platform 3 is disposed at the lower end of the sample cell base 7.

[0036] The sample cell housing 6 is a fixed glass cylinder with an open bottom and smooth edges. The lower edge of the cylinder is in close contact with the upper surface of the sample cell base 7, forming a movable, sealed space. Several evenly distributed small air inlets are located on both sides of the sample cell housing 6 for air intake. The sample cell housing 6 is fixed together with the laser galvanometer and other components and does not need to be moved. The objective lens 5 can be accessed from above the cylinder.

[0037] The collection cup 10 is located in the center inside the sample cell housing 6. An air inlet pipe is connected to each side of the collection cup 10 to fix it inside the sample cell housing 6, and the air outlet is on the side.

[0038] The sample cell base 7 is a flat and smooth glass surface that can be in close contact with the sample cell housing 6. When the sample cell base 7 moves, it forms a dynamic seal with the sample cell housing 6, and the sample cell housing 6 and the sample cell base 7 form a movable sealed space. The sample holder 2 is set above the sample cell base 7 and is used to hold the sample.

[0039] In a preferred embodiment, the dynamically sealed sample cell further includes a sample holder 2 lifting platform, which comprises a sample platform, a lifting assembly, and a sealing assembly 9. The sample holder 2 lifting platform is mounted on the sample cell base 7. The upper end of the lifting assembly is connected to the lower end of the sample platform. The sealing assembly 9 is located outside the lifting assembly, with its upper end connected to the lower end of the sample platform and its lower end connected to the upper surface of the sample cell base 7. The sealing assembly 9 is a corrugated pipe to reduce contamination within the sample cell. By controlling the height of the lifting platform, the Z-axis position of the sample in the sample cell can be controlled, ensuring both good sealing and accurate focusing.

[0040] In a preferred embodiment, the dynamically sealed sample cell further includes a moving platform 3, which is disposed at the lower end of the sample cell base 7. The moving platform 3 is a high-precision three-axis moving platform 3, which is integrated with the sample cell base 7 and the sample holder 2. By controlling the high-precision three-axis moving platform 3 to move precisely on the XY axis, the sample cell base 7, the sample holder 2, and the sample are moved in the XY axis direction, thereby changing the horizontal position of the sample in the sample cell.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0042] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dynamically sealed sample cell for a laser ablation system, characterized in that, include: Sample cell housing, collection cup, air inlet, air outlet, sample holder, and sample cell base; The air inlet and air outlet are provided on the sample cell shell, and the sample holder is provided on the sample cell base; The collection cup and the air outlet are connected and fixed inside the sample cell housing; The sample cell housing is a cover-shaped structure with an opening at one end. The upper surface of the sample cell base is a smooth plane. The lower end of the sample cell housing and the upper surface of the sample cell base are in slidable and sealed contact. The lower end of the sample cell housing and the upper surface of the sample cell base form a movable sealed space. The sample cell base can move in the XY axis direction to change the horizontal position of the sample in the dynamic sealed sample cell.

2. The dynamically sealed sample cell according to claim 1, characterized in that, The sample cell housing is a glass cylinder with an opening at the bottom and smooth edges, and the sample cell base is a glass with a flat and smooth surface.

3. The dynamically sealed sample cell according to claim 1, characterized in that, It also includes a sample holder lifting platform, which includes a sample platform, a lifting component and a sealing component, and the sample holder lifting platform is mounted on the sample pool base; The upper end of the lifting assembly is connected to the lower end of the sample platform; The sealing assembly is located outside the lifting assembly. The upper end of the sealing assembly is connected to the lower end of the sample platform, and the lower end of the sealing assembly is connected to the upper surface of the sample pool base.

4. The dynamically sealed sample cell according to claim 3, characterized in that, The sealing component is a bellows.

5. The dynamically sealed sample cell according to claim 1, characterized in that, It also includes a mobile platform, which is located at the lower end of the sample cell base.

6. The dynamically sealed sample cell according to claim 5, characterized in that, The mobile platform is a high-precision three-axis mobile platform.

7. The dynamically sealed sample cell according to claim 1, characterized in that, The sample cell shell has multiple evenly distributed air inlets on both sides.

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