Low-temperature steady-state sampling device and method for ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis of unstable liquid sample

Abstract

The invention discloses a low-temperature steady-state sampling device and method for ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis of an unstable liquid sample. The low-temperature steady-state sampling device comprises a low-temperature control module and an online degassing module which are sequentially arranged in a flow path from a sample source to an ICP-MS atomizer, the low-temperature control module is used for cooling the liquid sample in the flow path and maintaining the liquid sample in a preset low-temperature state; and the online degassing module is used for removing gas contained in the liquid sample in the flow path. The sample is maintained in a preset low-temperature state of 1-10 DEG C through the low-temperature control module, the decomposition rate of the unstable liquid sample can be reduced, generation of gas is reduced from the source, and a foundation is laid for subsequent stable analysis; the gas contained in the sample can be effectively removed by combining the online degassing module, so that the gas generated by sample decomposition entering the plasma is reduced, the disturbance of the plasma state is avoided, the stable operation of the plasma is ensured, and the analysis continuity and the signal stability are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of analytical chemistry, in particular to a low-temperature steady-state sample introduction device and method for ICP-MS analysis of unstable liquid samples. BACKGROUND

[0002] With the continuous progress of semiconductor manufacturing process, the purity requirement of wet electronic chemicals (such as cleaning agents, etching solutions) used in the process has reached G4 (ppb level) or even G5 (ppt level). The metal impurity content of high-purity hydrogen peroxide (H2O2) as a key cleaning and etching component directly affects the yield and performance of chips. ICP-MS is the main analysis method for monitoring its purity.

[0003] However, H2O2 is extremely unstable in chemical properties and can slowly decompose into water and oxygen (2H2O2→2H2O+O2↑) at room temperature. During the sample introduction process of ICP-MS, this instability is significantly amplified, causing a series of serious technical problems: 1. Disturbance of plasma state: During the process of passing through the peristaltic pump tube, connecting pipeline and entering the atomizer, the sample will accelerate decomposition and produce a large amount of oxygen due to friction, environmental temperature change and shear force. These oxygen enters the central channel along with the aerosol and rushes into the high-temperature argon plasma. The influx of oxygen will cause the so-called "plasma load effect", leading to a decrease in plasma temperature, a change in ionization efficiency, and thus a dramatic fluctuation in analysis signal and a decrease in sensitivity. In the case of high H2O2 concentration, the plasma may even be extinguished, interrupting the analysis.

[0004] 2. Unstable sample delivery: The micro-bubbles produced by the decomposition of H2O2 will form an air plug in the small sample introduction pipeline, causing discontinuous and unstable delivery of the peristaltic pump. This pulsed sample delivery makes the amount of liquid entering the atomizer vary, and the density of the aerosol also changes dramatically, ultimately resulting in extremely unstable noise signals on the detector, leading to poor precision (relative standard deviation RSD) of the analysis results.

[0005] 3. Safety and reproducibility issues: The decomposition rate of H2O2 is difficult to accurately control, making the conditions of each analysis inconsistent, which seriously affects the reproducibility and reliability of the analysis results.

[0006] Currently, the conventional methods in the industry are limited and ineffective. For example, high dilution of the sample can slow down the decomposition, but will severely sacrifice the analysis sensitivity, which cannot meet the needs of ultra-trace analysis. Some ICP-MS is equipped with a cooled mist chamber, which functions to cool the aerosol after its formation to reduce the solvent vapor entering the plasma; however, it cannot solve the problem of decomposition of H2O2 in the liquid line before entering the atomizer, so it has little effect on stabilizing the H2O2 sample analysis.

[0007] Therefore, there is an urgent need for a new sample introduction device and method that can inhibit the decomposition of H2O2 in the entire sample introduction process from the root cause and eliminate the already generated gas interference. SUMMARY

[0008] The purpose of the present application is to provide a low-temperature steady-state sample introduction device and method for ICP-MS analysis of unstable liquid samples to solve the problems raised in the background art. To achieve the above purpose, the present application provides the following technical solutions: The first aspect of the present application provides a low-temperature steady-state sample introduction device for ICP-MS analysis of unstable liquid samples, comprising a low-temperature control module and an online degassing module arranged in the flow path from the sample source to the ICP-MS atomizer in sequence; the low-temperature control module is used to cool and maintain the liquid sample in the flow path at a preset low-temperature state; the online degassing module is used to remove the gas contained in the liquid sample in the flow path.

[0009] Preferably, the preset low-temperature state is 1-10°C, preferably 2-5°C.

[0010] Preferably, the low-temperature control module comprises a sample introduction line, a heat exchange component, a refrigeration component, a temperature sensor and a temperature control unit; the refrigeration component and the temperature sensor are respectively electrically connected with the temperature control unit; the sample introduction line is connected between the sample source and the online degassing module, the heat exchange component is in contact with the liquid sample in the sample introduction line for heat exchange, the refrigeration component is connected with the heat exchange component, and the temperature sensor is used to monitor the temperature of the liquid sample in the sample introduction line.

[0011] Preferably, the refrigeration component is a semiconductor refrigeration sheet.

[0012] Preferably, the heat exchange component is a cooling jacket, which is wrapped outside the sample introduction line.

[0013] Preferably, the online degassing module comprises a hydrophobic gas permeable membrane line, which is connected between the sample introduction line and the ICP-MS atomizer.

[0014] Preferably, the online degassing module further comprises a degassing chamber and a degassing device, the hydrophobic gas-permeable membrane tubing is placed in the degassing chamber, and the degassing device is in communication with the degassing chamber.

[0015] Preferably, the components in the low-temperature control module and the online degassing module that are in direct contact with the liquid sample in the flow path are preferably made of perfluoroalkoxy polymer or polytetrafluoroethylene.

[0016] Preferably, the liquid sample is a hydrogen peroxide solution with a concentration greater than or equal to 10% (w / w).

[0017] The second aspect of the present application provides a low-temperature steady-state sampling method for ICP-MS analysis of unstable liquid samples, comprising the following steps: Cooling: cooling and maintaining the liquid sample at a preset low-temperature state before the liquid sample reaches the ICP-MS atomizer from the sample source; Degassing: removing the gas contained in the cooled liquid sample before the liquid sample reaches the ICP-MS atomizer; Analysis: introducing the liquid sample treated by cooling and degassing into the ICP-MS atomizer for analysis.

[0018] The present application has the following beneficial effects: the present application can significantly reduce the decomposition rate of unstable liquid samples by maintaining the sample at a preset low-temperature state of 1-10°C through the low-temperature control module, thereby reducing the generation of gas from the source and laying a foundation for subsequent stable analysis; and the online degassing module can effectively remove the gas contained in the sample, thereby avoiding the formation of air plugs in the flow path, ensuring the continuity and stability of sample delivery, reducing the noise of the detector signal, improving the analysis precision, reducing the gas generated by sample decomposition into the plasma, avoiding the disturbance of the plasma state, ensuring the stable operation of the plasma, and ensuring the continuity of the analysis and the stability of the signal; the device has a reasonable modular structure and can be used as a "plug and play" accessory to seamlessly connect with existing ICP-MS equipment, and has strong universality and practicality. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The structure diagram of the low-temperature steady-state sampling device for ICP-MS analysis of unstable liquid samples of the present application.

[0021] Figure 2 Structure diagram of the low-temperature control module of the present application.

[0022] Figure 3 Structure diagram of the online degassing module of the present application.

[0023] Figure 4 Flow chart of the low-temperature steady-state sample introduction method for ICP-MS analysis of unstable liquid samples of the present application.

[0024] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner so as not to affect the understanding of the reader. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0027] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0028] In addition, the terms "mount", "set", "provided with", "connect", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0029] As Figure 1As shown, the present embodiment discloses a low-temperature steady-state injection device for ICP-MS analysis of unstable liquid samples, which is hydrogen peroxide solution with concentration greater than or equal to 10% (w / w). The injection device is integrated in the flow path of the liquid sample from the sample source / sample container to the ICP-MS atomizer, which includes a full-range low-temperature control module 1 and an online degassing module 2 arranged in the flow path between the sample source and the ICP-MS atomizer in sequence.

[0030] The full-range low-temperature control module 1 is used for active and constant low-temperature control of the liquid sample in the flow path, which cools and maintains the liquid sample in the flow path at a preset low-temperature state. The preset low-temperature state is 1-10°C, preferably 2-5°C, which can effectively inhibit the decomposition rate of the unstable liquid sample without adversely affecting the properties of the sample.

[0031] The online degassing module 2 is connected in series after the full-range low-temperature control module 1 and before the atomizer, which is used to remove trace gases (such as oxygen) generated by the decomposition of the liquid sample online while maintaining the liquid sample lossless.

[0032] In a preferred embodiment, referring to Figure 2 The full-range low-temperature control module 1 includes a sample injection pipeline 11, a heat exchange component 12, a refrigeration component 13, a temperature sensor 14, and a temperature control unit 15. The refrigeration component 13 and the temperature sensor 14 are electrically connected to the temperature control unit 15. The sample injection pipeline 11 is connected between the sample source and the online degassing module 2 for transporting the liquid sample. The heat exchange component 12 directly or indirectly exchanges heat with the liquid sample in the sample injection pipeline 11 to cool the liquid sample; as an example, the heat exchange component 12 is preferably a cooling jacket, which is wrapped outside the sample injection pipeline 11, has a large contact area, and can improve the heat exchange efficiency to ensure uniform cooling of the sample in the sample injection pipeline 11. The refrigeration component 13 is connected to the heat exchange component 12 to provide cold energy for the heat exchange component 12; as an example, the refrigeration component 13 is preferably a semiconductor refrigeration sheet, which is attached to the outside of the heat exchange component 12, has the advantages of high refrigeration efficiency and convenient control. The temperature sensor 14 is used to monitor the temperature of the liquid sample in the sample injection pipeline 11 and transmit the temperature signal to the temperature control unit 15; the temperature control unit 15 dynamically adjusts the operating power of the refrigeration component 13 according to the deviation between the real-time temperature signal fed back by the temperature sensor 14 and the preset temperature value, thereby realizing precise control of the sample temperature.

[0033] In a preferred embodiment, referring to Figure 3 The online degassing module 2 includes a hydrophobic gas-permeable membrane pipeline 21, which is connected between the sample injection pipeline 11 and the ICP-MS atomizer, and the gas contained in the liquid sample can be separated out through the hydrophobic gas-permeable membrane when the liquid sample flows through the pipeline.

[0034] To further improve the degassing efficiency, in a preferred embodiment, referring to Figure 3 The online degassing module 2 further comprises a degassing chamber 22 and a degassing device 23, the hydrophobic gas-permeable membrane pipeline 21 is placed in the degassing chamber 22, and the degassing device 23 is in communication with the degassing chamber 22; the degassing device 23 can create a specific environment, such as a negative pressure environment or the introduction of inert gas, to promote the rapid removal of gas from the hydrophobic gas-permeable membrane pipeline 21 and be collected or discharged, thereby improving the gas removal efficiency and laying a solid foundation for the accuracy and stability of ICP-MS trace element analysis.

[0035] As an example, the degassing chamber 22 and the degassing device 23 can adopt a negative pressure degassing mode: the degassing device 23 is a vacuum pump, a negative pressure environment is constructed by the vacuum pump in communication with the degassing chamber 22, and the diffusion acceleration effect of gas molecules under low pressure conditions is utilized to promote the high-efficiency penetration of dissolved gas in high-purity hydrogen peroxide solution through the membrane to complete the removal. In another embodiment, the degassing chamber 22 and the degassing device 23 can also adopt an inert purge mode: high-purity argon and other inert purge gases are supported to be connected, based on the gas displacement principle, the gas components to be removed in the solution are quickly displaced and carried out.

[0036] To avoid contamination of device components to the liquid sample and ensure the accuracy of the analysis results, in a preferred embodiment, all components in the low-temperature control module 1 and the online degassing module 2 that are in direct contact with the liquid sample in the flow path (including the sample inlet pipeline 11, the hydrophobic gas-permeable membrane pipeline 21, the pipeline joints, etc.) are made of chemically inert, corrosion-resistant, and low-metal-leaching materials, preferably perfluoroalkoxy polymer or polytetrafluoroethylene materials.

[0037] Based on the same inventive concept as the above low-temperature steady-state sample introduction device for ICP-MS analysis of unstable liquid samples, the present embodiment also discloses a low-temperature steady-state sample introduction method for ICP-MS analysis of unstable liquid samples, referring to Figure 4 , comprising the following steps: S1, cooling: before the liquid sample reaches the ICP-MS atomizer from the sample source, the liquid sample is cooled and maintained at a preset low temperature state. Specifically, before the liquid sample reaches the ICP-MS atomizer from the sample source, the liquid sample is cooled and maintained at a preset low temperature state by the low-temperature control module 1, the preset low temperature state is 1-10°C, preferably 2-5°C. The temperature control unit 15 controls the operation of the refrigeration unit 13, the refrigeration unit 13 exchanges heat with the liquid sample in the sample inlet pipeline 11 through the heat exchange unit 12, and the temperature sensor 14 monitors the sample temperature in real time and feeds back to the temperature control unit 15 to realize stable temperature control.

[0038] S2, degassing: before the cooled liquid sample reaches the ICP-MS nebulizer, the gas contained in the liquid sample is removed. Specifically, the liquid sample flows through the hydrophobic gas-permeable membrane pipeline 21, and under the specific environment created by the removal device 23, the gas in the sample permeates the hydrophobic gas-permeable membrane into the removal chamber 22, and is treated by the removal device 23.

[0039] S3, analysis: the liquid sample treated by cooling and degassing is introduced into the ICP-MS nebulizer for analysis to obtain accurate data related to trace impurities in the sample.

[0040] Performance comparison experiment: Example: using the device and method disclosed in the embodiment, the preset low temperature state is set, the target temperature is set to 4°C, the 30% (w / w) G5 grade high-purity hydrogen peroxide solution is continuously analyzed for 2 hours, and the internal standard element 103 Rh signal is monitored. The results show that, 103 the relative standard deviation (RSD) of the Rh signal is 1.8%, the signal intensity has no significant downward trend throughout the process, and the plasma has been running stably.

[0041] Comparative example: using the same ICP-MS directly connected to the sample source, the same batch of 30% H2O2 sample is analyzed. Within 10 minutes after the start of analysis, it can be observed that the internal standard signal fluctuates sharply and irregularly, and the RSD exceeds 15%. After about 30 minutes, due to excessive oxygen load, the plasma is automatically extinguished, and the analysis is forced to stop.

[0042] The performance comparison experiment proves that the present application can effectively solve the instability problem of ICP-MS analysis of unstable liquid samples, and obtain analysis performance that traditional methods cannot achieve.

[0043] Based on the above examples, the low-temperature steady-state sample introduction device and method for ICP-MS analysis of unstable liquid samples of the present application have at least the following advantages compared with the prior art: 1. effectively inhibit sample decomposition: by maintaining the sample at a preset low temperature state of 1-10°C through the low temperature control module, the decomposition rate of the unstable liquid sample can be significantly reduced, the generation of gas is reduced from the source, and the foundation for subsequent stable analysis is laid. 2. improve sample delivery stability: the online degassing module can effectively remove the gas contained in the sample, avoid the formation of air plugs in the flow path due to bubbles, ensure the continuity and stability of sample delivery, reduce the noise of the detector signal, and improve the analysis precision. 3. ensure stable operation of the plasma: reduce the gas generated by sample decomposition entering the plasma, avoid disturbance of the plasma state, ensure stable operation of the plasma, and ensure the continuity of the analysis and the stability of the signal. 4. Reduce the risk of sample contamination: the components in direct contact with the sample are made of perfluoroalkoxy polymer or polytetrafluoroethylene material, which reduces the risk of sample contamination by the components and ensures the accuracy of the analysis results.

[0044] 5. Convenient operation and strong applicability: the device adopts a modular structure design and is reasonable in design, can be used as a "plug and play" accessory to seamlessly dock with the existing ICP-MS equipment, has strong versatility and practicality, and is convenient to operate and suitable for ICP-MS analysis of various unstable liquid samples such as hydrogen peroxide solution with a concentration greater than or equal to 10% (w / w).

[0045] For the embodiments of the present application, it should also be noted that the embodiments and features in the embodiments of the present application can be combined with each other to obtain new embodiments without conflict.

[0046] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. The protection scope of the present application should be subject to the protection scope of the claims. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solutions of the present application, and any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application are still within the scope of the technical solutions of the present application.

Claims

1. A low temperature steady state sample introduction device for ICP-MS analysis of unstable liquid samples, characterized in that, The application relates to a low-temperature control module (1) and an online degassing module (2) which are arranged in sequence in a flow path from a sample source to an ICP-MS atomizer; the low-temperature control module (1) is used for cooling and maintaining a liquid sample in the flow path at a preset low-temperature state; and the online degassing module (2) is used for removing gas contained in the liquid sample in the flow path.

2. A low temperature steady state sample introduction device for ICP-MS analysis of an unstable liquid sample according to claim 1, characterized in that, The preset low-temperature state is 1-10 DEG C, preferably 2-5 DEG C.

3. The low temperature steady state sample introduction device for ICP-MS analysis of unstable liquid samples according to claim 1, characterized in that, The low-temperature control module (1) comprises a sample inlet pipeline (11), a heat exchange part (12), a refrigeration part (13), a temperature sensor (14) and a temperature control unit (15); the refrigeration part (13) and the temperature sensor (14) are electrically connected with the temperature control unit (15) respectively; the sample inlet pipeline (11) is connected between a sample source and the online degassing module (2); the heat exchange part (12) is in contact with the liquid sample in the sample inlet pipeline (11) for heat exchange; the refrigeration part (13) is connected with the heat exchange part (12); and the temperature sensor (14) is used for monitoring the temperature of the liquid sample in the sample inlet pipeline (11).

4. A low temperature steady state sample introduction device for the ICP-MS analysis of unstable liquid samples according to claim 3, characterized in that, The refrigeration part (13) is a semiconductor refrigeration sheet.

5. A low temperature steady state sample introduction device for the ICP-MS analysis of unstable liquid samples according to claim 3, characterized in that, The heat exchange part (12) is a cooling jacket which is wrapped outside the sample inlet pipeline (11).

6. The low temperature steady state sample introduction device for ICP-MS analysis of unstable liquid samples of claim 1, wherein, The online degassing module (2) comprises a hydrophobic gas-permeable membrane pipeline (21) which is connected between the sample inlet pipeline (11) and an ICP-MS atomizer.

7. A low temperature steady state sample introduction device for the ICP-MS analysis of unstable liquid samples according to claim 6, characterized in that, The online degassing module (2) further comprises a removal chamber (22) and a removal device (23); the hydrophobic gas-permeable membrane pipeline (21) is arranged in the removal chamber (22); and the removal device (23) is in communication with the removal chamber (22).

8. The low temperature steady state sample introduction device for ICP-MS analysis of unstable liquid samples of claim 1, wherein, The components in the low-temperature control module (1) and the online degassing module (2) which are in direct contact with the liquid sample in the flow path are preferably made of perfluoroalkoxy polymer or polytetrafluoroethylene.

9. The low temperature steady state sample introduction device for ICP-MS analysis of unstable liquid samples of claim 1, wherein, The liquid sample is a hydrogen peroxide solution with a concentration greater than or equal to 10% (w / w).

10. A method for low temperature steady state sample introduction for ICP-MS analysis of unstable liquid samples, characterized in that, The application further discloses a method for analyzing a liquid sample by using the low-temperature control module (1) and the online degassing module (2), and the method comprises the following steps: cooling: cooling and maintaining the liquid sample at a preset low-temperature state before the liquid sample reaches an ICP-MS atomizer from a sample source; degassing: removing gas contained in the liquid sample before the cooled liquid sample reaches the ICP-MS atomizer; analysis: introducing the liquid sample which has been subjected to the cooling and degassing treatment into the ICP-MS atomizer for analysis.

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