A device for rapidly diagnosing matrix effects of a sampling substrate for laser micro-area chemical analysis

Abstract

The application discloses a kind of laser micro area chemical analysis sampling matrix effect rapid diagnostic device, the device includes laser for generating ablation laser, the dynamic ablation plume morphology formed by laser ablation sample is generated by probe light system The shadow formed by uniform irradiation of probe laser is transiently captured by first camera, then first camera will laser ablation plume macroscopic transient topography be transferred to computer;Ablation laser is focused on sample surface to form dynamically evolving plasma, and plasma spectrum signal is collected by spectrum signal receiver and is detected by spectrometer, and after spectrum data is imported into computer, the micro evolution law of ion, atomic, molecular spectrum signal in plasma at different times can be inverted;Microscopic spectroscopy and macroscopic ablation plume morphology method are combined, and the matrix difference of different samples under the same experimental conditions is diagnosed in real time on line, which is beneficial to select matrix matching standard sample to carry out laser micro area chemical analysis high-precision major and trace element content analysis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of geochemical analysis, and particularly relates to a device for rapidly diagnosing sampling matrix effect in laser micro-area chemical analysis. BACKGROUND

[0002] The laser sampling technology has been widely applied in many technical fields for material composition analysis, such as laser-induced breakdown spectroscopy (LIBS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), laser ablation inductively coupled plasma optical emission spectroscopy (LA-ICP-OES), laser ablation / ionization mass spectrometry (LAI-MS), and laser ablation microwave-induced plasma optical emission spectroscopy (LA-MIP-OES), as a sample introduction or ionization means. The laser ablation inductively coupled multi-receiving cup plasma mass spectrometry (LA-MC-ICP-MS) combining the laser ablation sampling technology with the mass spectrometry analysis technology has gradually become a powerful tool for micro-area in-situ element and isotope analysis of solid samples, due to its small sample consumption, fast testing speed, wide sample analysis range, high spatial resolution, and high analysis accuracy and precision.

[0003] However, the LA-ICP-MS accurate age analysis is often limited by the extreme lack of matrix matching standards and limited instrument analysis sensitivity, and the element fractionation and matrix effect have always seriously restricted the accuracy and precision of the analysis results, resulting in that some paragenetic minerals, such as calcium titanate, phosphorite, wolframite, fluorcarbonate cerium, garnet, monazite, titanite, rutile, and uranium ore, are greatly restricted in U-Pb dating analysis due to the lack of matrix matching standards. Therefore, there is an urgent need for a green, simple, effective, applicable, and easy-to-promote method to diagnose the matrix effect, select samples with small matrix effect gap as standard samples for calibration of the samples to be tested, and realize the selection and application of approximately non-matrix matching standards. SUMMARY

[0004] The present application aims to provide a device for rapidly diagnosing sampling matrix effect in laser micro-area chemical analysis, which is used for studying the dynamic morphology change of laser ablation plume when different types of pulsed laser ablate solid samples, combining the evolution law of micro ion, atom, and molecule spectra, revealing the laser and material interaction mechanism, and simultaneously used for sample matrix effect difference diagnosis, which is conducive to selecting matrix approximately matching standard samples and realizing accurate major and trace element content chemical analysis.

[0005] To achieve the above object, the technical scheme provided by the present application is as follows:

[0006] A device for rapidly diagnosing matrix effect of sampling substrate in laser micro-area chemical analysis, comprising a laser, a lens group, a first beam splitter, an ablation cell, a probe light system, a high-speed response detector, an oscilloscope, a shutter controller, a shutter, a pulse delay control generator, a first camera, a first filter, a computer, a spectrometer and a spectral signal receiver;

[0007] The laser is used to generate ablation laser, and the ablation laser is focused on the surface of the sample after being shaped by the lens group and passing through the first beam splitter and a focusing lens.

[0008] The sample is placed in a sealed cavity of the ablation cell, and the ablation cell is provided with three optical glass windows, one of which is used for transmission of ablation laser and reflected light, and the other two are arranged in parallel for transmission of probe light.

[0009] The relative time delay of laser pulses of the laser and the probe light system is measured in real time by two high-speed response detectors in combination with the oscilloscope, and the shutter controller controls the on-off of the laser of the laser and the probe light system through two shutters; the pulse delay control generator controls the relative response delay of the laser, the probe light system and the shutter controller, the dynamic ablation plume morphology formed by the ablation of the sample by the ablation laser is irradiated by the probe light, the shadow formed after passing through the first filter is captured by the first camera in an instant, and then the first camera transmits the macroscopic transient morphology of the laser ablation plume to the computer.

[0010] The pulse delay control generator also controls the relative delay of the laser and the spectrometer, the ablation laser is focused on the surface of the sample to form a dynamically evolving plasma, the plasma spectrum signal is reflected and collected by the spectral signal receiver after passing through the focusing lens and the first beam splitter, and then sent to the spectrometer, the spectral data are imported into the computer and processed by combining the machine learning algorithm to obtain the evolution law of the ion, atomic and molecular spectrum signals in the plasma at different times; and the macroscopic transient morphology of the laser ablation plume obtained by the first camera is used to diagnose the difference of matrix effect under the same experimental conditions.

[0011] Further, the device further comprises a precise three-dimensional moving platform, a second beam splitter, a second filter and a second camera.

[0012] The ablation cell is located on a precise three-dimensional moving platform, and the second beam splitter is located between the first beam splitter and the focusing lens; after the reflected light passes through the optical glass window and the second beam splitter, the second camera obtains a high-definition photo of the sample surface in the ablation cell by filtering light through the second filter; the second camera transmits image data to the computer, and the machine vision software in the computer identifies and transmits a control signal to the precise three-dimensional moving platform to control the movement of the precise three-dimensional moving platform, so that the automatic focusing of the ablation laser on the sample surface and the observation and selection of the ablation position are realized.

[0013] Further, the second camera is a high-resolution camera.

[0014] Further, the probe light system further comprises a frequency doubling crystal and a collimating lens.

[0015] The probe laser generated by the probe light system is frequency-doubled by the frequency doubling crystal, and then forms a parallel light beam by the collimating lens to irradiate the ablation plume.

[0016] Further, the ablation cell is provided with an air inlet and an air outlet, which are connected to a three-way air inlet pipeline and an air outlet pipeline respectively.

[0017] One channel of the three-way air inlet pipeline is connected to the carrier gas to realize the transmission of the aerosol after sampling, and the air outlet pipeline is connected to the inductively coupled plasma mass spectrometer for sampling operation; the other channel of the three-way air inlet pipeline is connected to a molecular pump, and when in use, the channel connected to the carrier gas and the air outlet are closed, and the ablation cell is pumped to vacuum, so that the plasma spectrum signal formed by the ablation laser is collected by the spectrometer under vacuum conditions, and the first camera takes a photo of the ablation plume morphology in real time.

[0018] Further, the first camera is a high-resolution camera.

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] The present application has important role in the field of geochemical analysis, and the dynamic morphology change of the laser ablation plume when the ablation environment is different for different types of pulsed laser ablation solid samples is studied, the evolution law of ion, atom and molecule spectrum is combined, the laser and material interaction mechanism is revealed, and the sample matrix effect difference diagnosis is used, which is beneficial to select the standard sample with approximate matching matrix, and realizes accurate major and trace element content chemical analysis. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic diagram of the laser micro-area chemical analysis sampling matrix effect rapid diagnosis device of the present application.

[0022] In the diagram: 1-Spectrometer, 2-Laser, 3-Pulse delay control generator, 4-Shutter controller, 5-Detector laser system, 6-Lens group, 7-First shutter, 8-First detector, 9-Oscilloscope, 10-Second detector, 11-Frequency doubling crystal, 12-Collimating lens, 13-Second shutter, 14-Spectral signal receiver, 15-First beam splitter, 16-Second beam splitter, 17-Focusing lens, 18-Three-way air inlet pipe, 19-Precision three-dimensional moving platform, 20-Etching cell, 21-Air outlet pipe, 22-Second camera, 23-First camera, 24-First filter, 25-Computer, 26-Second filter, 27-Sample, 28-First optical glass window, 29-Second optical glass window, 30-Third optical glass window. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for explaining the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0024] This invention provides a rapid diagnostic device for matrix effects in laser micro-area chemical analysis sampling. A short-wavelength nanosecond or femtosecond laser outputs a laser pulse as an ablation laser, which, after beam shaping, is focused onto the sample surface. The sample is placed in a laser ablation cell, which is positioned above a three-dimensional control platform and its position is controlled by the platform. The ablation cell can be evacuated or filled with different types of gas. A machine vision autofocusing system, including a movable precision three-dimensional platform, a high-resolution camera, and machine vision control software on a computer, enables automatic focusing of the ablation laser and observation and selection of the ablation location. Another short-wavelength nanosecond or femtosecond laser outputs a laser pulse as a probe laser, which, after beam shaping, becomes a parallel beam perpendicularly incident on the sample surface and then passes through a filter before entering the high-resolution camera. The ablation feather formed by the ablation laser ablation of the sample, and the shadow cast by the probe light, are transiently captured by the camera. The delay of both laser beams is controlled by a pulse delay control generator. The plasma spectral signal generated by the ablation laser is reflected and collected by a receiver, then sent to a spectrometer. Machine learning algorithms are used to process the spectral data, retrieving the evolution patterns of ion, atom, and molecular spectral signals at different times. A pulse delay control generator synchronously or delays the operation of the pump laser, probe laser, spectrometer, and camera. The camera monitors the ablation area and captures real-time images of the ablation plume and surface morphology. Two high-speed response detectors, combined with an oscilloscope, are used to detect the time delay of the two laser beams in real time. The evolution patterns of the microscopic spectral signal obtained from the spectrometer, combined with the macroscopic transient morphology of the laser ablation plume obtained from the high-response camera, allow for real-time online diagnosis of matrix effect differences under the same experimental conditions. This facilitates the selection of matrix-matched standard samples for high-precision analysis of major and trace element content in laser micro-area chemical analysis.

[0025] This invention plays an important role in fields such as geochemical analysis. It studies the dynamic morphological changes of laser ablation plumes when different types of pulsed laser ablation solid samples are subjected to ablation environments. Combined with the evolutionary laws of ion, atom, and molecular spectra at the microscopic level, it reveals the interaction mechanism between laser and matter. At the same time, it can be used to diagnose differences in sample matrix effects, which is beneficial for selecting standard samples with approximately matching matrices and achieving accurate chemical analysis of major and trace element contents.

[0026] The laser micro-area chemical analysis sampling matrix effect rapid diagnostic device of the present invention includes a spectrometer, a laser, a pulse delay control generator, a shutter controller, a probe light system, a lens group, a shutter, a detector, an oscilloscope, a spectral signal receiver, a frequency doubling crystal, a collimating lens, a beam splitter, a focusing lens, a three-way air inlet pipe, a three-dimensional movable platform, a specially designed three-optical-window sealed ablation cell, an air outlet pipe, a high-resolution camera, a filter, and a computer;

[0027] like Figure 1As shown, after the ablation laser 2 is shaped by the lens group 6, it passes through the first beam splitter 15 and the second beam splitter 16, and continues to output beams. These beams are then focused onto the surface of the sample 27 by the focusing lens 17 to complete the ablation.

[0028] Sample 27 is placed in a sealed cavity of ablation tank 20 above a precision three-dimensional moving platform 19. The bottom of the ablation tank 20 is fixed to the precision three-dimensional moving platform 19. Three windows with optical glass (such as calcium fluoride glass) are provided on the top of the ablation tank 20 to facilitate the transmission of laser and probe light. The first optical glass window 28 is used for ablation laser transmission, while the second optical glass window 29 and the third optical glass window 30 are used for probe laser transmission. Reflected light passes upward through the first optical glass window 28 and the second beam splitter 16, and is then filtered out by the second filter 26. This allows the second camera 22 to obtain a high-resolution image of the sample surface within the ablation tank 20. The second camera 22 transmits the image data to the computer 25, where machine vision software identifies and feeds back signals to control the movement of the precision three-dimensional moving platform 19, thereby achieving automatic and precise self-focusing of the laser relative to the sample surface. Simultaneously, it precisely locates the ablation position, achieving in-situ micro-area sampling of the sample.

[0029] The ablation cell 20 has air inlets and outlets on its front and rear sides, respectively connected to a three-way air inlet pipe 18 and an outlet pipe 21. One channel of the three-way air inlet pipe 18 can be used to introduce carrier gas for aerosol transport after sampling, and the outlet pipe 21 connects to an inductively coupled plasma mass spectrometer (ICP-MS) for sample introduction. The other channel can be connected to a molecular pump. During use, the channel for introducing carrier gas and the outlet 21 are closed, and the ablation cell 20 is evacuated to a vacuum. This allows the spectrometer 1 to acquire the plasma spectral signal generated by the ablation laser and the first camera 23 to take real-time photographs of the ablation plume morphology under vacuum conditions. High-resolution cameras can be used for both the first and second cameras.

[0030] The accurate relative time delay between the optical pulse signals of laser 2 and probe optical system 5 is measured in real time using two high-speed response detectors combined with oscilloscope 9. The first detector 8 detects the optical pulse signal of laser 2, and the second detector 10 detects the optical pulse signal of probe optical system 5, in order to accurately determine the relative time delay between the two pulses. Shutter controller 4 controls the first shutter 7 and the second shutter 13, thereby controlling the laser's on / off state. Pulse delay control generator 3 controls the relative response delay between laser 2, probe optical system 5, shutter controller 4, and spectrometer 1. The dynamic ablation feather morphology formed by the laser 2 focused on the surface of sample 27 is frequency-doubled by probe optical system 5 through frequency doubling crystal 11, and then collimated by collimating lens 12 to form a parallel beam illuminating the ablation feather. The probe light and the resulting shadow are filtered out by first filter 24 before being transiently captured by first camera 23, and the image data is then transmitted to computer 25 for real-time observation. The pulse delay control generator 3 controls the laser 2 and the spectrometer 1 to work with a relative delay. The laser 2 is finally focused on the surface of the sample 27 to form a dynamically evolving plasma. After the plasma spectral signal is reflected, it is collected by the spectral signal receiver 14 through the second beam splitter 16 and the first beam splitter 15, and then sent to the spectrometer 1. The spectrometer 1 imports the spectral data into the computer 25 and combines it with machine learning algorithms to process the spectral data, thereby reversing the evolution law of ion, atom and molecule spectral signals in the plasma at different times.

[0031] In summary, the device of this invention enables synchronous or delayed control of the pump laser, probe laser, and spectrometer by a pulse delay control generator. A camera monitors the ablation region and captures real-time images of the ablation surface morphology. Artificial intelligence technology enables automatic control of the three-dimensional control platform, achieving laser self-focusing on the sample surface. Two high-speed response detectors detect the time delay of the two laser beams in real time. The evolution of microscopic spectral signals is obtained from the spectrometer, and combined with the macroscopic transient morphology of the laser ablation plume obtained from the high-response CCD camera, real-time online diagnosis of matrix effect differences under the same experimental conditions is performed. This facilitates the selection of matrix-matched standard samples for high-precision analysis of major and trace element content in laser micro-area chemical analysis.

[0032] Application areas: This invention can be used in fields such as geochemical analysis and laser-matter interactions.

[0033] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for rapid diagnosis of matrix effects in sampling for laser microchemical analysis, characterized in that it comprises: The device comprises a laser, a lens group, a first beam splitter, an ablation cell, a probe light system, a high-speed response detector, an oscilloscope, a shutter controller, a shutter, a pulse delay control generator, a first camera, a first filter, a computer, a spectrometer and a spectrum signal receiver; The laser is used to generate ablation laser, which is shaped by the lens group, transmitted through the first beam splitter, and focused on the sample surface by a focusing lens to complete ablation. The sample is placed in the sealed cavity of the ablation cell, which is provided with three optical glass windows, one of which is used for transmission of ablation laser and reflected light, and the other two are arranged in parallel for transmission of probe light; the ablation cell is provided with an air inlet and an air outlet, which are connected to a three-way air inlet pipeline and an air outlet pipeline respectively; one channel of the three-way air inlet pipeline is connected to a carrier gas to realize transmission of aerosol after sampling, and the air outlet pipeline is connected to an inductively coupled plasma mass spectrometer for sampling operation; the other channel of the three-way air inlet pipeline is connected to a molecular pump, which is closed when in use to form a vacuum in the ablation cell, so that the spectrometer can collect plasma spectrum signals formed by the ablation laser under vacuum conditions, and the first camera can take real-time photos of the ablation plume morphology. The relative time delay of laser pulses of the laser and the probe light system is measured in real time by two high-speed response detectors combined with an oscilloscope, and the shutter controller controls the on-off of the laser of the laser and the probe light system through two shutters; the pulse delay control generator controls the relative response delay of the laser, the probe light system and the shutter controller, the dynamic ablation plume morphology formed by the ablation laser ablation of the sample is irradiated by the probe light generated by the probe light system, and the shadow formed by the irradiation is captured by the first camera after passing through the first filter, and then the first camera transmits the macroscopic transient morphology of the laser ablation plume to the computer; The pulse delay control generator also controls the relative delay of the laser and the spectrometer, the ablation laser is focused on the sample surface to form a dynamically evolving plasma, the plasma spectrum signal is reflected through the focusing lens and the first beam splitter, and then collected by the spectrum signal receiver, and then sent to the spectrometer, the spectrum data is imported into the computer and further processed by combining with the machine learning algorithm, so as to inverse the microscopic evolution law of ion, atomic and molecular spectrum signals in the plasma at different times; combined with the macroscopic transient morphology of the laser ablation plume obtained by the first camera, the real-time diagnosis of the matrix effect difference under the same experimental conditions is carried out. The device further comprises a precise three-dimensional moving platform, a second beam splitter, a second filter and a second camera. The ablation cell is located on the precise three-dimensional moving platform, and the second beam splitter is located between the first beam splitter and the focusing lens; the reflected light transmits through the optical glass window and the second beam splitter, and then filters through the second filter, so that the second camera obtains a high-definition photo of the sample surface in the ablation cell; the second camera transmits the image data to the computer, and then the machine vision software in the computer identifies and feeds back the control signal to the precise three-dimensional moving platform controller to control the movement of the precise three-dimensional moving platform, so as to realize the automatic focusing of the ablation laser on the sample surface and the observation and selection of the ablation position.

2. The apparatus according to claim 1, wherein The second camera is a high-resolution camera.

3. The apparatus according to claim 1, wherein The probe light system further comprises a frequency doubling crystal and a collimating mirror. The probe laser generated by the probe light system passes through the frequency doubling crystal for frequency doubling, and then is irradiated to the ablation plume in the form of parallel light beams by the collimating mirror.

4. The apparatus according to claim 1, wherein The first camera is a high-resolution camera.

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