Sample introduction device for ICP-MS

Abstract

The invention discloses a sampling device for ICP-MS (Inductively Coupled Plasma Mass Spectrometry) in the technical field of instrumental analysis. The sampling device comprises a liquid inlet mechanism and an atomization mechanism, the liquid inlet mechanism is used for inputting a liquid sample into the atomization mechanism, the atomization mechanism comprises a concentric atomizer and an atomization chamber, the concentric atomizer is communicated with the atomization chamber, and the atomization chamber is communicated with a waste liquid barrel and an ICP torch pipe; a self-cleaning mechanism is arranged on a communication path of the concentric atomizer and the atomizing chamber, the self-cleaning mechanism comprises a movable cylinder, the movable cylinder is rotationally connected into a nozzle of the concentric atomizer, contact electrodes are symmetrically arranged in the movable cylinder, and when the movable cylinder is blocked, the contact electrodes form a path; the contact electrode is electrically connected with a torsion mechanism and a reverse blowing mechanism, the torsion mechanism is used for twisting the movable cylinder when the contact electrode forms a path, and the reverse blowing mechanism is used for intercepting carrier gas input into the concentric atomizer and reversely blowing the carrier gas out of a nozzle of the concentric atomizer. According to the invention, self-cleaning can be carried out when blockage occurs in the sample introduction process, and sample analysis interruption caused by blockage is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of instrumental analysis, and specifically relates to a sample introduction device for ICP-MS. BACKGROUND

[0002] Inductively coupled plasma mass spectrometry (ICP-MS) has become an indispensable analytical tool in the fields of environmental monitoring, food safety, geological exploration, biomedicine and semiconductors due to its extremely low detection limit, high sensitivity and rapid multi-element analysis capability. The analysis process of the technology mainly includes three core links of sample introduction, ionization and mass spectrometry detection. Among them, the sample introduction system (i.e. the sample introduction device) as the key link connecting the sample to be tested and the high-temperature plasma directly determines the accuracy and reliability of the analysis results.

[0003] A typical ICP-MS sample introduction device is composed of a peristaltic pump, a nebulizer, a spray chamber and connecting pipelines, and its main function is to convert liquid samples into fine aerosols and transport them into the plasma for ionization. However, in the actual analysis process, clogging of the sample introduction system is a common problem that seriously affects continuous analysis, especially when dealing with complex samples such as high-salinity, suspended particles or organic matrix.

[0004] The prior art usually indirectly infers the occurrence of clogging by monitoring abnormal analysis data. For example, when the signal intensity of the internal standard element is observed to suddenly drop, the analysis precision significantly deteriorates (the RSD value abnormally increases), or the sample signal response continuously deviates from the calibration curve, the operator will suspect whether the sample introduction system is clogged. This judgment method has serious after-the-fact and lagging nature.

[0005] Especially in the early stage of clogging (micro-clogging stage), the nebulizer nozzle or capillary is only partially blocked, and the most direct manifestation is the slow decrease in atomization efficiency, resulting in a slow and gradual decrease in the sensitivity of all elements. Since this decrease is gradual and may be misjudged as normal fluctuations in instrument state, unstable plasma or sample matrix effect, it is difficult to be effectively detected by observing real-time signal data in real time. The operator often cannot identify and intervene in the early stage of the problem.

[0006] When the early signs of micro-clogging are ignored, the degree of clogging further aggravates until it is completely blocked, which causes the sample signal to suddenly interrupt or completely disappear. At this time, not only the current sample data being analyzed is declared invalid, but also the sequence analysis usually needs to be interrupted, and maintenance operations such as stopping, disassembling, cleaning or replacing parts are required. This not only causes waste of precious samples and loss of instrument time, but also may lead to failure of the entire analysis sequence, seriously affecting the analysis efficiency and output quality of the laboratory.

[0007] In view of the defects of the prior art, it is urgent to develop a sample injection device with real-time monitoring and self-cleaning function to realize early warning and automatic processing of blockage, thereby improving the analysis reliability, automation level and operation efficiency of ICP-MS. SUMMARY

[0008] In order to solve the above problems, the purpose of the present application is to provide a sample injection device for ICP-MS, which can self-clean when blockage occurs during the sample injection process, reducing the interruption of sample analysis caused by blockage.

[0009] In order to achieve the above purpose, the technical scheme of the present application is as follows: A sample injection device for ICP-MS, comprising a liquid inlet mechanism and an atomization mechanism; the liquid inlet mechanism is used for inputting liquid sample to the atomization mechanism, the atomization mechanism comprises a concentric atomizer and an atomization chamber, the concentric atomizer is communicated with the atomization chamber, and the atomization chamber is communicated with a waste liquid barrel and an ICP torch pipe; a self-cleaning mechanism is arranged on the communication path between the concentric atomizer and the atomization chamber, the self-cleaning mechanism comprises a movable cylinder, the movable cylinder is rotationally connected in the nozzle of the concentric atomizer, and symmetrical contact electrodes are arranged in the movable cylinder; when the movable cylinder is blocked, the contact electrodes form a passage; the contact electrodes are electrically connected with a torsion mechanism and a backflush mechanism, the torsion mechanism is used for torsioning the movable cylinder when the contact electrodes form the passage, and the backflush mechanism is used for intercepting the carrier gas input into the concentric atomizer and blowing out from the nozzle of the concentric atomizer in the reverse direction.

[0010] Working principle: the symmetrical contact electrodes arranged in the movable cylinder constitute an open circuit. In normal sampling, the two electrodes are separated by non-conductive carrier gas (such as argon) and sample mist flow, and the circuit is in an open state. When micro-blockage occurs, the conductive sample liquid film or droplet (the sample liquid generally forms an acidic aqueous solution after acid pretreatment, so it has conductivity) gradually covers the electrodes, thereby forming a conductive path between the two contact electrodes, and the circuit is connected.

[0011] The passage signal formed by the contact electrodes will immediately trigger two parallel execution mechanisms--the torsion mechanism and the backflush mechanism, starting a short but powerful automatic cleaning cycle: After receiving the electrical signal, the torsion mechanism drives the movable cylinder to perform rapid and limited-angle reciprocating torsion at its connection. The shear and torsion force generated by the reciprocating torsion can effectively mechanically strip the viscous liquid film or soft deposits attached to the inner wall of the concentric atomizer and the nozzle.

[0012] Almost at the same time, the backflush mechanism acts. It first intercepts the carrier gas flow path normally flowing to the concentric atomizer, and then turns the high-pressure carrier gas flow into the nozzle of the concentric atomizer in the reverse direction. This high-speed reverse gas flow directly impacts the loosened blockage caused by torsion force, blowing it away from the blockage position, thereby completely unblocking the nozzle.

[0013] The above scheme has the following beneficial effects: 1. The scheme directly detects the earliest possible time of the blockage event (micro-blockage stage), overturning the traditional lag mode of indirect inference by analyzing signals. The problem is solved at the embryonic stage, avoiding the development of micro-blockage into complete blockage.

[0014] 2. The scheme greatly improves the analysis efficiency and automation level, avoiding analysis interruption: there is no need to pause the analysis sequence, disassemble and clean or replace the concentric atomizer due to blockage, ensuring the continuity and integrity of long-term and large-batch sample analysis.

[0015] 3. The cleaning action is automatically completed inside the system without disassembly, avoiding damage risk or secondary pollution caused by human operation.

[0016] Further, the twisting mechanism includes a movable slot formed in the side wall of the concentric atomizer, a first electromagnet and an iron core are arranged in the movable slot, the iron core is in sliding fit with the movable slot, the iron core is fixedly connected with the movable cylinder, a spring is arranged between the iron core and the first electromagnet, and the first electromagnet is electrically connected with the contact electrode.

[0017] Beneficial effect: the contact electrode is disconnected, the first electromagnet is powered off, and there is no magnetism. At this time, the iron core is in the initial position (e.g. pushed to one end of the movable slot) under the pre-pressure of the spring, and the movable cylinder connected therewith is also in the default initial angle. When the contact electrode forms a path due to the bridging of the blockage, the circuit is connected, the first electromagnet is powered on instantaneously, and a strong magnetic field is generated. The electromagnet generates a magnetic force to attract the iron core, overcome the elastic force of the spring, and make the iron core slide quickly in the movable slot. The iron core drives the movable cylinder to rotate (i.e. twist).

[0018] The power-on response time of the first electromagnet is in the millisecond level, which can provide strong magnetic attraction force instantaneously to drive the iron core and the movable cylinder to produce a quick and powerful twisting action.

[0019] Further, the backflushing mechanism includes a groove formed in the inner side wall of the gas inlet end of the concentric atomizer, a guide plate is rotatably connected in the groove side wall, a torsional spring is arranged at the connection between the guide plate and the groove side wall, the torsional spring is used to support the guide plate to reset, a second electromagnet is further arranged in the groove side wall, the second electromagnet is opposite to the guide plate, the guide plate is made of magnetic material, and the second electromagnet is used to generate a magnetic field with the same magnetic property as the guide plate; the groove is communicated with a reverse channel, the outlet of the reverse channel faces the movable cylinder, and the gas flow direction in the reverse channel is opposite to that of the sample liquid.

[0020] Beneficial effect: the second electromagnet is powered off, and no magnetic field is generated. Under the support of the torsion spring, the guide plate remains in the reset state, and is flat and collected in the side wall of the groove, and the surface is smooth and flush with the inner wall of the concentric atomizer air inlet end. At this time, the carrier gas (such as Ar gas) from the gas source can flow along the normal path without any obstruction, enter the concentric atomizer core, and after mixing with the sample liquid, be sprayed forward (toward the nozzle) to form a high-speed gas flow for atomization.

[0021] When the contact electrode forms a path, the signal reaches the second electromagnet at the same time. The second electromagnet is powered on instantaneously, and generates a magnetic field of the same magnetic property as the guide plate (i.e. same magnetic poles) according to the design. According to the principle of same magnetic poles repelling each other, the magnetic field generated by the second electromagnet generates a strong repulsive force (thrust) on the guide plate made of magnetic material. This repulsive force overcomes the elastic force of the torsion spring and pushes the guide plate to quickly rotate and pop out of the groove, like a barrier across the air flow channel. The popped-out guide plate almost instantaneously cuts off the normal carrier gas flow path flowing forward. At the same time, the carrier gas intercepted by the guide plate is forced to enter the reverse channel connected with the groove. The high-pressure gas is sprayed out of the outlet of the reverse channel at high speed. Since the outlet is directed towards the movable cylinder and the direction is opposite to the sample flow direction, a strong counter-blowing gas flow is formed, which directly hits the nozzle area where clogging may occur.

[0022] When the cleaning pulse ends, the second electromagnet is powered off, and the magnetic field disappears. The repulsive force on the guide plate disappears, and the elastic force of the torsion spring drives the guide plate to rotate in the opposite direction, so that it is re-collected in the groove and returns to the state of being flush with the inner wall. The carrier gas flow path returns to normal, and continues to transport the sample forward for atomization.

[0023] Further, the light source emitter and the light detector are arranged on the path of communication between the concentric atomizer and the atomization chamber, the light source emitter is used for emitting light to the atomized aerosol, and the light detector is used for capturing the Tyndall image formed after the light passes through the aerosol; the control unit is used for judging the atomization condition of the aerosol based on the Tyndall image, and further judging whether the concentric atomizer is clogged, and controlling the operation of the torsion mechanism and the back-blowing mechanism based on the judgment result.

[0024] Beneficial effect: according to the Tyndall effect, when light passes through a colloidal dispersion system (such as an aerosol), it will be scattered by suspended small particles, so that a light path can be observed on the side of the light propagation path. The density and particle size distribution of the aerosol directly affect the intensity and shape of the light path.

[0025] Normal state: when the atomization is good, the aerosol particles are small, uniform and high in density, and have a strong scattering effect on light, so the light detector can capture a Tyndall light spot with high intensity, stable and uniform shape.

[0026] Abnormal state (initial stage of clogging): When the concentric atomizer starts to clog, the atomization efficiency decreases. The most direct manifestation is: The total amount of aerosol generated decreases → leading to the overall intensity of scattered light weakening.

[0027] The particle size distribution of atomization changes (more large droplets) → leading to changes in the morphology and uniformity of scattered light.

[0028] The control unit receives and analyzes the image signals from the light detector in real time. Through pre-set algorithms (such as comparing the baseline intensity, analyzing the uniformity of light spot gray scale distribution, etc.), it can sensitively identify the gradual trend of the above light intensity and morphology.

[0029] Optical monitoring captures the direct physical manifestation of the decrease in atomization efficiency, which may even detect abnormalities earlier than electrode monitoring. Because in some cases, the clogging material may not have connected the electrode yet, but the atomization effect has already deteriorated. This further advances the early warning time point, truly achieving prevention before the problem occurs.

[0030] Electrode monitoring may produce false signals due to changes in the conductivity of the sample itself (such as different acidity), accidental passage of bubbles, and other factors. Optical monitoring verifies from another physical dimension (optical properties).

[0031] Furthermore, the control unit is also used to determine whether the contact electrode is a false touch based on the Tyndall image, and control the on-off of the circuit of the twisting mechanism and the blowback mechanism; if it is determined to be a true clogging, the circuit is immediately closed to perform the cleaning action; if it is determined to be a false touch, the circuit remains open and the cleaning action is not performed.

[0032] Beneficial effects: fundamentally eliminate false cleaning, and ensure the absolute continuity of the analysis sequence and the integrity of the data. The system can intelligently distinguish between real clogging and transient interference, avoiding the sudden activation of blowback and twisting due to an accidental bubble or particle at the most inappropriate time (such as when a valuable sample is being data collected), thereby ensuring the seamless continuity of the analysis process without human intervention.

[0033] Furthermore, the control unit determines the aerosol atomization condition based on the following logic: analyze the intensity and uniformity of the Tyndall image; compare the intensity and uniformity with the pre-set intensity reference range and pre-set uniformity reference range, respectively; if the intensity continuously falls below the pre-set intensity reference range and / or the uniformity continuously deviates from the pre-set uniformity reference range, it is determined that the atomization state is abnormal, indicating that clogging has occurred.

[0034] Beneficial effects: Monitoring two interrelated but independent physical parameters (intensity and uniformity) at the same time is equivalent to providing double evidence for diagnosis, which is much more accurate than single parameter judgment (such as relying on intensity alone), greatly reducing the misdiagnosis rate.

[0035] Further, the control unit is also used to record the aerosol atomization condition at each moment, and based on the change of the aerosol atomization condition within the continuous time node, analyze and judge the blocking trend, draw the degradation curve of the performance of the concentric atomizer, and predict the time node of complete cleaning or replacement based on the degradation curve; and the display unit is used to display the prediction result.

[0036] Beneficial effects: The control unit analyzes the historical data and draws the change of intensity and uniformity over time into a curve. Under normal circumstances, it is a relatively stable straight line.

[0037] When the performance starts to degrade, the curve will show a slow but continuous downward or deterioration trend. Through algorithms such as linear regression, moving average analysis, etc., the control unit can quantify this degradation rate. Based on the current performance value, the degradation rate, and the preset performance failure threshold (such as intensity less than 50% of the normal value), a prediction model is established. This model can extrapolate the performance degradation curve, so as to calculate when (for example: after how many hours of operation) the performance will reach the critical point that requires complete cleaning or replacement.

[0038] The performance degradation curve provides objective and quantitative data to evaluate the status of the concentric atomizer, changing the uncertainty of relying on the experience and feeling of the operator for judgment in the past. Predictive maintenance based on the actual health status of the equipment. Maintenance is only carried out when necessary, maximizing the service life of the concentric atomizer, while absolutely avoiding unexpected failures without warning.

[0039] Further, the light source emitter is a laser diode, and the light detector is a CCD or CMOS image sensor; the display unit is integrated into the control software interface of the ICP-MS host, and is used to visually display the real-time Dallay image, intensity and uniformity values, historical performance degradation curve and predicted maintenance time node.

[0040] Beneficial effects: The laser light source ensures the stability and high intensity of the Dallay effect signal, so that it can be clearly captured even when the aerosol density starts to decrease slightly, greatly improving the monitoring sensitivity and facilitating the identification of the earliest micro-blockage.

[0041] Further, the outlet end of the reverse channel is provided with a one-way mechanism, which only allows the carrier gas to flow out of the reverse channel.

[0042] Beneficial effect: when the instrument is working normally, the pressure inside the concentric atomizer (nozzle) is close to or slightly higher than atmospheric pressure. At this time, there is no gas flow or low pressure in the reverse channel, and the one-way mechanism is tightly closed under the action of its own structure or external atmospheric pressure. It ensures that the normally generated aerosol and sample droplets will not flow back into the reverse channel, thereby avoiding sample residue, cross contamination or crystallization in the channel itself.

[0043] Further, a pressure sensor is arranged in the reverse channel of the concentric atomizer for monitoring the pressure of the carrier gas; and the control unit is further configured to, when the back flushing mechanism is actuated, if the pressure value monitored by the pressure sensor does not rise to the expected back flushing pressure value within a preset time, the control unit determines that the back flushing mechanism is faulty or the reverse channel is blocked, and triggers an alarm information to be sent to the display unit.

[0044] Beneficial effect: the pressure sensor is precisely arranged inside the reverse channel for directly monitoring the pressure change in the special gas path. When the system is working normally and no back flushing is performed, the pressure in the reverse channel is atmospheric pressure (or a known baseline pressure value). When the back flushing mechanism is triggered, the flow guide plate intercepts the flow, and the high-pressure carrier gas rushes into the reverse channel, which theoretically causes the pressure in this place to rise sharply to a very high, predictable expected back flushing pressure value (this value can be determined in advance by experiment and stored in the control unit) within a very short time.

[0045] If the pressure value does not reach the expected back flushing pressure within a preset time, it indicates that the reverse channel may have a fault (such as the flow guide plate being stuck or the reverse channel being blocked), which avoids the continuous deterioration of the micro-blockage due to the failure of back flushing, and ensures the actual effect of the self-cleaning mechanism. If the pressure is always zero or lower than the baseline, it may be that the reverse channel is blocked; if the pressure rises slowly or does not reach the threshold, it may be that the flow guide plate is not tightly sealed or the electromagnet has insufficient magnetic force. The control unit accurately determines the fault type according to the pressure data, avoids the disassembly of the entire sample introduction system for troubleshooting by the operator, and improves the maintenance efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The figure is a schematic diagram of the sample introduction of the sample introduction device for ICP-MS.

[0047] Figure 2 The figure is a schematic diagram of the internal structure of the concentric atomizer in the sample introduction device for ICP-MS.

[0048] Figure 3 The figure is a schematic diagram of the internal structure of the concentric atomizer in the sample introduction device for ICP-MS. Figure 2 The figure is a schematic diagram of the internal structure of the concentric atomizer in the sample introduction device for ICP-MS.

[0049] Figure 4 The figure is a schematic diagram of the internal structure of the concentric atomizer in the sample introduction device for ICP-MS. Figure 3 The figure is a schematic diagram of the internal structure of the concentric atomizer in the sample introduction device for ICP-MS.

[0050] Figure 5 For Figure 2 Local enlarged view at N in the middle.

[0051] The reference signs in the drawings of the specification comprise: 1, sample; 2, peristaltic pump; 3, concentric atomizer; 4, atomization chamber; 5, waste liquid barrel; 6, ICP torch tube; 301, air inlet end; 302, light source emitter; 303, light detector; 304, nozzle; 305, movable cylinder; 306, contact electrode; 307, reverse channel; 308, guide plate; 309, groove; 310, second electromagnet; 311, movable slot; 312, spring; 313, iron core; 314, first electromagnet. DETAILED DESCRIPTION

[0052] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar reference signs indicate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are for the purpose of explaining the present application only, and are not to be understood as limiting the present application.

[0053] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "vertical", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0054] In the description of the present application, unless otherwise specified and limited, it should be noted that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection or electrical connection, it can be the communication between the two elements, it can be direct connection, or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by those skilled in the art according to the specific circumstances.

[0055] The specific embodiments are described in detail below: The embodiments are substantially as described in the accompanying Figures 1-5As shown: a sample injection device for ICP-MS, mainly comprising a liquid inlet mechanism and an atomization mechanism; the liquid inlet mechanism is used for inputting liquid sample 1 to the atomization mechanism, the atomization mechanism comprises a concentric atomizer 3 and an atomization chamber 4, the concentric atomizer 3 adopts a Meinhard type concentric atomizer 3, the concentric atomizer 3 communicates with the atomization chamber 4, and the atomization chamber 4 is communicated with a waste liquid barrel 5 and an ICP torch pipe 6. Preferably, the liquid inlet mechanism comprises a peristaltic pump 2, a sample 1 tube and a sample needle. The rotation speed of the peristaltic pump 2 is set to 2 mL / min, and the sample 1 is pumped from the sample 1 tube to the sample 1 capillary of the concentric atomizer 3 through a silica gel tube (this is a prior art, which is described in detail herein).

[0056] A self-cleaning mechanism is arranged on the communication path between the concentric atomizer 3 and the atomization chamber 4, and the self-cleaning mechanism comprises a movable cylinder 305, as shown in Figure 2 and Figure 3 As shown, an annular groove is formed in the nozzle 304 of the concentric atomizer 3 (the nozzle 304 is the place where gas and liquid are mixed to form a high-speed gas flow to atomize the liquid), and the movable cylinder 305 is rotationally connected in the annular groove, as shown in Figure 3 and Figure 4 As shown, the movable cylinder 305 is symmetrically embedded with contact electrodes 306, preferably, the contact electrodes 306 are arc-shaped structures, when the movable cylinder 305 is blocked, the conductive medium (the blocking material generated by the sample 1 liquid) is attached and connected between the contact electrodes 306, and a passage is formed between the two contact electrodes 306; the contact electrodes 306 are electrically connected with a torsion mechanism and a backflush mechanism, the torsion mechanism is used for torsion of the movable cylinder 305 when the passage is formed in the contact electrodes 306, specifically, the torsion mechanism comprises an arc-shaped movable groove 311 formed in the side wall of the concentric atomizer 3, a first electromagnet 314 and an iron core 313 are embedded in the movable groove 311, the iron core 313 is in sliding fit with the movable groove 311, the iron core 313 is welded and fixed with the movable cylinder 305, a spring 312 is adhesively fixed between the iron core 313 and the first electromagnet 314, and the first electromagnet 314 is electrically connected with the contact electrodes 306 through wires.

[0057] The backflush mechanism is used for intercepting the carrier gas input into the concentric atomizer 3 and blowing out from the nozzle 304 of the concentric atomizer 3 in the reverse direction. Specifically, as shown in Figure 2 and Figure 5As shown, the back flushing mechanism includes a groove 309 opened on the inner side wall of the gas inlet end 301 of the concentric atomizer 3 (the position of carrier gas input, in this embodiment, the carrier gas is pure 99.999% argon), a flow guide plate 308 is rotatably connected in the side wall of the groove 309, a torsional spring is sleeved on the rotating shaft, and the two ends of the torsional spring are respectively embedded in the flow guide plate 308 and the side wall of the groove 309. The torsional spring is used to support the flow guide plate 308 to reset. A second electromagnet 310 is also embedded in the side wall of the groove 309, and the second electromagnet 310 is opposite to the flow guide plate 308. The flow guide plate 308 is made of a magnetic material, and the second electromagnet 310 is used to generate a magnetic field with the same magnetic property as the flow guide plate 308. The groove 309 is communicated with a reverse channel 307, and the outlet of the reverse channel 307 faces the movable cylinder 305, and the gas flow direction in the reverse channel 307 is opposite to the flow direction of the sample 1 liquid (combined with the attached Figure 3 Preferably, the outlet end of the reverse channel 307 is provided with a one-way mechanism (such as a one-way valve: umbrella valve, etc.), which only allows the carrier gas to flow out of the reverse channel 307. In this embodiment, the one-way mechanism is a rotating plate (not shown in the figure), and the rotating plate and the outlet end of the reverse channel 307 are also rotatably connected through a rotating shaft, and a torsional spring is also sleeved on the rotating shaft. When the sample injection device is working normally, the pressure in the nozzle 304 is close to or slightly higher than the atmospheric pressure. At this time, there is no gas flow or low pressure in the reverse channel 307, and the rotating plate is kept tightly closed (i.e. tightly adheres to the inner wall of the nozzle 304) under the action of the external atmospheric pressure. When high-pressure carrier gas is introduced into the reverse channel 307, the pressure in the channel rises sharply, and when the pressure exceeds the opening pressure (torsional spring force) of the one-way mechanism and the external atmospheric pressure, the rotating plate is pushed away, and the high-pressure gas is successfully sprayed out, forming a reverse blowing gas flow.

[0058] Preferably, a light source emitter 302 and a light detector 303 are also arranged on the communication path between the concentric atomizer 3 and the atomization chamber 4. Preferably, the light detector 303 is symmetrically installed on the right side of the atomization chamber 4, and the light source emitter 302 is a laser diode, and the light detector 303 is a CCD or CMOS image sensor. The light source emitter 302 is used to emit light to the atomized aerosol, and the light detector 303 is used to capture the Tyndall image formed after the light passes through the aerosol.

[0059] The control unit is also used to judge the atomization condition of the aerosol based on the Tyndall image. Specifically, the intensity and uniformity of the Tyndall image are analyzed, and the intensity and uniformity are compared with the preset intensity reference range and the preset uniformity reference range respectively. If the intensity continuously falls below the preset intensity reference range and / or the uniformity continuously deviates from the preset uniformity reference range, it is judged that the atomization state is abnormal. Then it is judged whether the concentric atomizer 3 is blocked, and the operation of the torsion mechanism and the back flushing mechanism is controlled based on the judgment result.

[0060] The control unit is also used to determine whether the contact electrode 306 is a false touch based on the Tyndall image, and control the on-off of the circuit of the first electromagnet 314 and the second electromagnet 310; if it is determined to be a blockage, the circuit is immediately closed to start the self-cleaning program; if it is determined to be a false touch, the circuit remains open and no cleaning action is performed.

[0061] The control unit is also used to record the aerosol atomization condition at each moment, and analyze and determine the blockage trend based on the change of the aerosol atomization condition within the continuous time nodes, draw a degradation curve of the performance of the concentric atomizer 3, and predict the time node of complete cleaning or replacement based on the degradation curve; and further comprising a display unit integrated in the control software interface of the ICP-MS host, used for visual display of the real-time Tyndall image, intensity and uniformity numerical value, historical performance degradation curve and predicted maintenance time node.

[0062] Preferably, a pressure sensor is further included, which is embedded in the reverse channel 307 of the concentric atomizer 3 and used to monitor the carrier gas pressure; the control unit is also used to determine that the electromagnet is faulty or the reverse channel 307 is blocked when the second electromagnet 310 is powered on, and the pressure value monitored by the pressure sensor does not rise to the expected backblowing pressure value within a preset time, and an alarm information is sent to the display unit.

[0063] The specific implementation process is as follows: Normal sampling stage: Start the ICP-MS instrument, and continuously input the carrier gas (high-purity argon) into the carrier gas inlet of the concentric atomizer 3 at a set flow rate (usually 0.8-1.2 L / min).

[0064] Start the peristaltic pump 2 to pump the liquid sample 1 into the sample 1 capillary of the concentric atomizer 3 at a constant flow rate. At the atomizer nozzle 304, the high-speed gas flow meets the liquid to form uniform and fine aerosols. After these aerosols enter the atomization chamber 4, the larger droplets are separated and discharged, and the fine droplets are transported to the ICP torch 6 along with the carrier gas, and are ionized in the high-temperature plasma for mass spectrometric detection.

[0065] During this period, the laser beam emitted by the laser diode penetrates the aerosol cloud emitted from the nozzle 304, producing a significant Tyndall effect. The CCD image sensor continuously captures the image of the light path and transmits it to the control unit, which calculates the gray average value (intensity) and standard deviation (uniformity) of the image in real time, and compares it with the preset reference range set in the initialization stage. If the value is within the normal range, the system determines that the atomization state is good.

[0066] At this time, the contact electrodes 306 are separated by the airflow and mist droplets, and the circuit is in an open state. The deflector 308 is tightly collected in the groove 309 under the action of the torsional spring, and is flush with the inner wall of the concentric atomizer 3, without any obstruction to the normal airflow. The one-way valve (turning plate) at the outlet of the reverse channel 307 is in a closed state due to the absence of internal pressure.

[0067] Micro-plugging and intelligent identification process: When processing high-salinity or complex matrix sample 1, dissolved substances or micro-particles in the sample 1 may gradually deposit on the inner wall of the movable cylinder 305 at the nozzle 304, forming a micro-plug.

[0068] The most direct impact of this process is the slow reduction of atomization efficiency. The performance is as follows: a) The total amount of aerosol generated is reduced -> the overall intensity of the Tyndall image shows a slow and continuous downward trend.

[0069] b) The atomization particle size distribution is poor, and large droplets increase -> the uniformity of the Tyndall light spot (such as the image gray scale standard deviation) continuously deteriorates, and the light spot appears irregular light and dark distribution.

[0070] At the same time, the conductive sample 1 liquid film or deposit will adhere to the inner wall of the movable cylinder 305, bridging the two symmetrical contact electrodes 306, making them form a path, generating an electrical signal.

[0071] After receiving the electrode signal, the control unit does not immediately trigger cleaning, but starts a double verification mechanism: It immediately retrieves and analyzes the optical monitoring data (i.e. Tyndall image) in the current and previous period of time.

[0072] If the optical signal (intensity and uniformity) also shows a continuously deteriorating trend starting from the same time point, the control unit determines that it is a true blockage.

[0073] If only the electrode path signal is present, and the optical signal is stable and normal, the control unit determines that it is a false touch (possibly caused by a single bubble or particle accidentally passing through), and ignores the signal, only records the event log, and the system continues to sample normally, thereby effectively preventing false actions.

[0074] Self-cleaning trigger and execution process (taking the case of determining a true blockage): Once the control unit confirms the occurrence of a blockage, it immediately sends a short pulse current to the first electromagnet 314 of the torsional mechanism and the second electromagnet 310 of the backflush mechanism at the same time.

[0075] Torsion action: First electromagnet 314 is powered instantly to generate a strong magnetic force, attracting the iron core 313 to slide quickly in the active slot 311 against the spring 312. Since the iron core 313 is fixedly connected to the active cylinder 305, this linear motion is converted into a rapid torsion of the active cylinder 305. This action generates a strong mechanical shearing force on the blockage attached to the inner wall, causing it to loosen and peel off. After the pulse current ends (or the blockage is cleared), the first electromagnet 314 is powered off, and the spring 312 pushes the iron core 313 and the active cylinder 305 to reverse torsion and reset. This rapid forward and reverse torsion can efficiently break and peel off the deposits.

[0076] At the same time, the second electromagnet 310 is powered on to generate a magnetic field of the same magnetic property as the flow guide plate 308. According to the principle of same property repulsion, a strong magnetic repulsion instantly pushes the flow guide plate 308 against the spring's elastic force, causing it to quickly pop out of the groove 309 to the center of the airflow passage, completely cutting off the normal forward flow path of the carrier gas.

[0077] The cut-off high-pressure carrier gas has nowhere to go, and the pressure rises sharply, forcing it to flow into the reverse channel 307 connected to the groove 309. The high-pressure gas pushes the rotating plate at the outlet of the reverse channel 307 to open, forming a high-speed, pulse-like reverse purge gas flow that is ejected from the outlet and directly hits the inner wall of the active cylinder 305. This reverse gas flow works in conjunction with the torsion action: the torsion mechanism scrapes off the blockage, and the reverse blowing gas flow then blows it away, completely clearing the nozzle 304.

[0078] After the cleaning pulse ends, the first and second electromagnets 310 are powered off. The flow guide plate 308 quickly returns to the groove 309 under the action of the torsion spring, re-establishing the smooth flow of the airflow passage. The one-way valve (rotating plate) closes under the action of its own torsion spring and external atmospheric pressure, sealing the reverse channel 307. The system immediately returns to the normal sampling state.

[0079] The control unit continuously monitors the optical signal that follows. If the intensity and uniformity of the Tyndall image quickly returns to the normal baseline range, it proves that the cleaning is successful, and the system records a successful cleaning event.

[0080] During the reverse blowing action, the control unit reads the data of the pressure sensor in the reverse channel 307. If the pressure value fails to rise as expected, it is determined that the reverse blowing mechanism may have a fault (such as electromagnet failure, flow guide plate 308 jamming, or reverse channel 307 blockage), and an explicit warning message (such as "reverse blowing failure, please check and maintain") is immediately generated on the display unit, prompting the operator to intervene, thereby avoiding the system running silently in a fault state.

[0081] Predictive maintenance process: The control unit continuously records the atomization health data (intensity and uniformity values) during each analysis process. After a long-term operation, the system software can draw the degradation curve of the performance of the concentric atomizer 3 (such as the slow downward trend of sensitivity over time). By analyzing this trend through an algorithm, the system can predict the time point when the performance drops to an unacceptable level, and give an early warning to the operator through the display unit (such as "concentric atomizer 3 needs to be cleaned after 70 hours"). This allows the laboratory manager to plan maintenance when the instrument is idle, achieve predictive maintenance, maximize instrument operating efficiency and service life, and avoid interruptions due to sudden complete blockage during important analysis tasks.

[0082] The above-mentioned is only the embodiment of the present application, and the common knowledge of the specific structure and / or characteristics in the scheme is not described in detail. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A sample introduction device for ICP-MS, comprising a liquid inlet mechanism and an atomization mechanism; the liquid inlet mechanism is used for inputting a liquid sample (1) to the atomization mechanism, the atomization mechanism comprises a concentric atomizer (3) and an atomization chamber (4), the concentric atomizer (3) is communicated with the atomization chamber (4), and the atomization chamber (4) is communicated with a waste liquid tank (5) and an ICP torch pipe (6); characterized in that: A self-cleaning mechanism is arranged on a communication path between the concentric atomizer (3) and the atomization chamber (4), and the self-cleaning mechanism comprises a movable cylinder (305) which is rotationally connected in a nozzle (304) of the concentric atomizer (3), and symmetrical contact electrodes (306) are arranged in the movable cylinder (305), and the contact electrodes (306) form a passage when the movable cylinder (305) is blocked; the contact electrodes (306) are electrically connected with a torsion mechanism and a back-blowing mechanism, the torsion mechanism is used for torsion of the movable cylinder (305) when the contact electrodes (306) form the passage, and the back-blowing mechanism is used for intercepting carrier gas input into the concentric atomizer (3) and reversely blowing out from the nozzle (304) of the concentric atomizer (3).

2. The sample introduction device for ICP-MS according to claim 1, characterized by: The torsion mechanism comprises a movable groove (311) which is arranged in a side wall of the concentric atomizer (3), a first electromagnet (314) and an iron core (313) are arranged in the movable groove (311), the iron core (313) is in sliding fit with the movable groove (311), the iron core (313) is fixedly connected with the movable cylinder (305), a spring (312) is arranged between the iron core (313) and the first electromagnet (314), and the first electromagnet (314) is electrically connected with the contact electrodes (306).

3. The sample introduction device for ICP-MS of claim 1, wherein: The back-blowing mechanism comprises a groove (309) which is arranged in a side wall of an air inlet end (301) of the concentric atomizer (3), a guide plate (308) is rotationally connected in the side wall of the groove (309), a torsion spring is arranged at a connection position of the guide plate (308) and the side wall of the groove (309) and is used for supporting the guide plate (308) to reset, a second electromagnet (310) is further arranged in the side wall of the groove (309), the second electromagnet (310) is arranged opposite to the guide plate (308), the guide plate (308) is made of a magnetic material, and the second electromagnet (310) is used for generating a magnetic field which has the same magnetism as the guide plate (308); and the groove (309) is communicated with a reverse channel (307), an outlet of the reverse channel (307) faces the movable cylinder (305), and a gas flow direction in the reverse channel (307) is opposite to a sample (1) liquid flow direction.

4. The sample introduction device for ICP-MS according to claim 3, characterized by: The concentric atomizer (3) and the atomization chamber (4) are further communicated with a light source emitter (302) and a light detector (303), the light source emitter (302) is used for emitting light to the atomized aerosol, and the light detector (303) is used for capturing a Tyndall image formed after the light passes through the aerosol; and a control unit is further arranged, and the control unit is used for judging the aerosol atomization condition based on the Tyndall image, judging whether the concentric atomizer (3) is blocked, and controlling operation of the torsion mechanism and the back-blowing mechanism based on a judgment result.

5. The sample introduction device for ICP-MS of claim 4, wherein: The control unit is further used for judging whether the contact electrodes (306) are false touch based on the Tyndall image, and controlling on-off of a circuit of the torsion mechanism and the back-blowing mechanism; if it is judged that the concentric atomizer (3) is blocked, the circuit is immediately closed, and a cleaning action is performed; and if it is judged that the contact electrodes (306) are false touch, the circuit is kept off, and the cleaning action is not performed.

6. The sample introduction device for ICP-MS of claim 4, wherein: The control unit judges the aerosol atomization condition based on the following logic: intensity and uniformity of the Tyndall image are analyzed; the intensity and the uniformity are compared with a preset intensity reference range and a preset uniformity reference range, respectively; If the intensity continuously falls below the preset intensity reference range and / or the uniformity continuously deviates from the preset uniformity reference range, it is determined that the atomization state is abnormal, and it is determined that clogging occurs.

7. The sample introduction device for ICP-MS of claim 6, wherein: The control unit is also used to record the aerosol atomization condition at each moment, analyze and determine the clogging trend based on the change of the aerosol atomization condition within the continuous time nodes, draw the degradation curve of the performance of the atomizer, and predict the time node of complete cleaning or replacement based on the degradation curve; and further comprising a display unit, which is used to display the prediction results.

8. The sample introduction device for ICP-MS of claim 7, wherein: The light source emitter (302) is a laser diode, and the light detector (303) is a CCD or CMOS image sensor; the display unit is integrated in the control software interface of the ICP-MS host, and is used to visually display the real-time Tyndall image, intensity and uniformity values, historical performance degradation curve and predicted maintenance time node.

9. The sample introduction device for ICP-MS of claim 3, wherein: The outlet end of the reverse channel (307) is provided with a one-way mechanism that only allows the carrier gas to flow out of the reverse channel (307).

10. The sample introduction device for ICP-MS of claim 7, wherein: Further comprising a pressure sensor arranged in the reverse channel (307) of the concentric atomizer (3) for monitoring the carrier gas pressure; the control unit is also used to determine that the back flushing mechanism fails or the reverse channel (307) is clogged and trigger an alarm information to be sent to the display unit if the pressure value monitored by the pressure sensor does not rise to the expected back flushing pressure value within a preset time when the back flushing mechanism is actuated.

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