Atomic fluorescence excitation beam adjustment system and adjustment method based on single photon

Abstract

The present invention relates to the field of atomic fluorescence detection technology, and in particular to a single-photon-based atomic fluorescence excitation beam adjustment system and an adjustment method thereof. The system includes a sampling module, an atomization module, a light source excitation module, an electric displacement platform and a spectral imaging module. The sampling module is used to feed a sample into the atomization module, the atomization module is used to atomize the sample, the light source excitation module is used to excite the sample to produce an atomic fluorescence spectrum of a target element, the electric displacement platform is used to adjust the position of a light source in the light source excitation module, and the spectral imaging module is used to perform spectral imaging on the atomic fluorescence spectrum of the target element, and analyze the imaging data to adjust the light source to the optimal excitation position. The present invention combines the atomic fluorescence spectrum with the imaging of the flame excitation area, and can effectively adjust the excitation position to the optimal state, no longer relying on human eye observation and empirical judgment, and improving the accuracy of the detection result.

Description

Technical Field

[0001] The invention belongs to the technical field of atomic fluorescence detection, and in particular relates to an AFS excitation light beam adjustment system based on single photons and an adjustment method thereof. Background Art

[0002] my country is a major country in the application of atomic fluorescence spectroscopy (AFS). AFS instruments have become important routine detection instruments and are widely used in environmental testing, food hygiene, water quality monitoring and other fields. Instrument products based on hydride generation-atomic fluorescence spectroscopy (HG-AFS) can effectively detect and analyze 12 inorganic metal elements such as arsenic (As), antimony (Sb), bismuth (Bi), and mercury (Hg), and have the advantages of low matrix interference and high sensitivity.

[0003] Existing AFS instruments mainly use the dispersion detection method to achieve atomic fluorescence detection. The general process of the dispersion detection method is: the sample to be tested enters the atomizer after the hydride reaction, the target element in the sample to be tested is atomized and forms an argon-hydrogen flame, and the atomic fluorescence spectrum of the target element in the argon-hydrogen flame is excited by the excitation light beam. The atomic fluorescence spectrum is first collimated by the slit and then projected onto the dispersion element. The atomic fluorescence spectrum is dispersed and then evenly projected onto the imaging detector.

[0004] If the excitation beam is not aligned with the optimal reaction position of the argon-hydrogen flame, the excitation process of the target element will be limited, including: 1. Most of the atomized target elements cannot be effectively excited, resulting in distortion of the test results. Since the atomic fluorescence detection method mainly detects heavy metal elements in samples such as food and agricultural products, these heavy metal elements are harmful to the human body. The most direct manifestation is that the toxic and harmful target elements in the sample to be tested are not fully excited, resulting in the mistaken belief that there is not enough toxic and harmful substances in the sample to be tested. 2. The atomic fluorescence signal intensity of the entire detection process is weak, and elements with less content cannot be effectively detected, which reduces the performance indicators of the instrument.

[0005] At present, the correction of the excitation position is mainly through human observation and experience judgment. The excitation light source is manually adjusted and the signal strength change is judged to confirm whether the excitation position is adjusted to the optimal state. However, the direct problem caused by this method is that the adjustment of the optimal state in each detection process often has to be judged through experience, and the repeatability and standardization of the optimal state adjustment cannot be guaranteed, which will lead to deviations in the detection performance of each instrument, and even different detection results due to different operators. Summary of the invention

[0006] In view of this, the present invention aims to provide an excitation beam adjustment system and an adjustment method for atomic fluorescence dispersion detection, so as to solve the technical problem that the prior art relies on human eye observation and experience judgment, resulting in low accuracy of detection results.

[0007] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0008] A single-photon based AFS excitation beam adjustment system includes a sample injection module, an atomization module and a light source excitation module. The sample injection module is used to send a sample into the atomization module. The atomization module is used to atomize a target element in the sample to form an argon-hydrogen flame. The light source excitation module is used to excite the target element to make the electrons outside the nucleus of the target element transition and generate the atomic fluorescence spectrum of the target element. The single-photon based AFS excitation beam adjustment system also includes an electric displacement platform, a two-dimensional precision displacement platform and a spectral imaging module.

[0009] The electric displacement platform is used to adjust the position and angle of the light source excitation module;

[0010] The spectral imaging module includes a spectral signal collection submodule and a spectral signal processing submodule;

[0011] The spectral signal collection submodule includes an incident slit, a dispersion element, and a planar array position-sensitive anode single-photon counting imager. The incident slit is used to collimate the atomic fluorescence spectrum of the target element, the dispersion element is used to expand the collimated atomic fluorescence spectrum in space according to the wavelength, and the planar array position-sensitive anode single-photon counting imager is used to collect the atomic fluorescence spectrum after the wavelength expansion;

[0012] The two-dimensional precision displacement platform is used to adjust the position of the spectral signal collection submodule to achieve slit scanning imaging;

[0013] The spectral signal processing submodule includes an imaging splicing unit, an atomic fluorescence spectrum line identification unit, and a light source adjustment unit;

[0014] The imaging splicing unit is used to splice the spectral imaging of different excitation areas of the argon-hydrogen flame to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame;

[0015] The atomic fluorescence spectrum recognition unit is used to determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectrum image; if it appears, the position and angle of the light source in the light source excitation module are kept unchanged; if it does not appear and a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame, the light source adjustment unit sends an adjustment instruction to the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, and the electric displacement platform corrects the posture deviation of the light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if it does not appear and a light source scattering interference signal excited by the light source appears in the lower half of the argon-hydrogen flame, the light source adjustment unit sends an adjustment instruction to the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, and the electric displacement platform corrects the posture deviation of the light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

[0016] Furthermore, the sampling module includes a carrier gas tank, a sample tank, a reducing agent tank, a peristaltic pump, a reactor, a gas-liquid separator and a waste liquid recovery device. The carrier gas tank is connected to the gas-liquid inlet of the gas-liquid separator through a pipeline, the sample tank and the reducing agent tank are connected to the inlet of the peristaltic pump through a pipeline, the outlet of the peristaltic pump is connected to the inlet of the reactor through a pipeline, the outlet of the reactor is connected to the gas-liquid inlet of the gas-liquid separator through a pipeline, the waste liquid discharge port of the gas-liquid separator is connected to the waste liquid recovery device, and the gas-liquid outlet of the gas-liquid separator is connected to the atomization module through a pipeline.

[0017] Furthermore, the atomization module is a flame atomizer.

[0018] Furthermore, the light source excitation module includes N light sources distributed at N lamp positions around the atomization module, 2≤N≤4, and each light source is a sharp line light source or a continuous light source.

[0019] Furthermore, the continuous light source is a xenon arc lamp, and the sharp line light source is a hollow cathode lamp.

[0020] Furthermore, the number of the electric displacement platforms is the same as the number of the light sources, and each light source is mounted on a corresponding electric displacement platform.

[0021] An excitation beam adjustment method for atomic fluorescence dispersion detection is implemented using the above-mentioned excitation beam adjustment system, comprising the following steps:

[0022] S1: The sample to be tested is sent into the excitation beam adjustment system for excitation, and the atomic fluorescence spectrum excited by the target element in the sample to be tested is collected by different equivalent pixel positions of the area array position-sensitive anode single photon counting imager;

[0023] S2: By controlling the two-dimensional precision displacement platform to adjust the spectral signal collection submodule, different excitation areas of the argon-hydrogen flame are scanned and spliced ​​to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame after splicing;

[0024] S3: Determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectral image; if so, keep the position and angle of the light source in the light source excitation module unchanged; if not and a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame, then the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if not and a light source scattering interference signal excited by the light source appears in the lower half of the argon-hydrogen flame, then the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

[0025] Furthermore, the spectrum image is equally divided from top to bottom into the upper half area of ​​the argon-hydrogen flame, the central area of ​​the argon-hydrogen flame, and the lower half area of ​​the argon-hydrogen flame;

[0026] The spectral imaging detection method is used to identify the atomic fluorescence spectrum lines excited by the target element in the spectral image and the light source scattering interference signal excited by the light source;

[0027] The spectral imaging detection method is used to identify whether the atomic fluorescence spectrum lines excited by the target element appear in the central area of ​​the argon-hydrogen flame;

[0028] The spectral imaging detection method is used to identify whether a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame or the lower half of the argon-hydrogen flame.

[0029] Furthermore, if no atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame and a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame, the irradiation position of the light source is lowered through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if no atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame and a light source scattering interference signal excited by the light source appears in the lower half of the argon-hydrogen flame, the irradiation position of the light source is raised through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

[0030] Compared with the prior art, the invention can achieve the following beneficial effects:

[0031] The present invention combines atomic fluorescence spectrum with flame excitation area imaging, which can effectively adjust the excitation position to the optimal state, no longer rely on human observation and experience judgment, and improve the accuracy of the detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0033] Figure 1 A schematic diagram of the structure of an excitation beam adjustment system for atomic fluorescence dispersion detection according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of a scenario in which images of different excitation areas of an argon-hydrogen flame are stitched together according to an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of a situation in which the light source excitation position of an embodiment of the present invention is relatively high;

[0036] Figure 4 A schematic diagram of a situation in which the light source excitation position of an embodiment of the present invention is relatively low.

[0037] Description of reference numerals:

[0038] Injection module 1, carrier gas tank 11, sample tank 12, reducing agent tank 13, peristaltic pump 14, reactor 15, gas-liquid separator 16, waste liquid recovery tank 17, atomization module 2, light source excitation module 3, spectral signal collection module 4, incident slit 41, dispersion element 42, array position-sensitive anode single photon counting imager 43, spectral signal processing module 5. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0042] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0043] The following will refer to the attached Figure 1 -Attached Figure 4 The invention is described in detail with reference to the embodiments.

[0044] The excitation beam adjustment system for atomic fluorescence dispersion detection provided in an embodiment of the present invention comprises a sample injection module 1, an atomization module 2, a light source excitation module 3, an electric displacement platform (not shown in the figure), a two-dimensional precision displacement platform (not shown in the figure) and a spectral imaging module; wherein the sample injection module 1 is used to feed the sample into the atomization module; the atomization module 2 is used to atomize the target element in the sample; the light source excitation module 3 is used to excite the atomized target element, so that the electrons outside the nucleus of the target element are excited to transition, and the atomic fluorescence spectrum of the target element is generated; the spectral imaging module is used to perform spectral imaging on the atomic fluorescence spectrum of the target element.

[0045] The sampling module 1 includes a carrier gas tank 11, a sample tank 12, a reducing agent tank 13, a peristaltic pump 14, a reactor 15, a gas-liquid separator 16 and a waste liquid recovery tank 17; wherein the carrier gas tank 11 is connected to the gas-liquid inlet of the gas-liquid separator 16 through a pipeline, the sample tank 12 and the reducing agent tank 13 are connected to the inlet of the peristaltic pump 14 through a pipeline, the outlet of the peristaltic pump 14 is connected to the inlet of the reactor 15 through a pipeline, the outlet of the reactor 15 is connected to the gas-liquid inlet of the gas-liquid separator 16 through a pipeline, the waste liquid discharge port of the gas-liquid separator 16 is connected to the waste liquid recoverer, and the gas-liquid outlet of the gas-liquid separator 16 is connected to the atomization module 2 through a pipeline.

[0046] The sample stored in the sample tank 12 and the reducing agent stored in the reducing agent tank 13 are pumped into the reactor 12 by the peristaltic pump 14 to react, generating hydrides and hydrogen of the target elements contained in the sample, which enter the gas-liquid separator 16 under the propulsion of the carrier gas to separate the water vapor in the sample, and then enter the atomization module 2.

[0047] The atomization module 2 adopts a flame atomizer. After high-temperature treatment by the flame atomizer, the target element in the sample is atomized and an argon-hydrogen flame is formed.

[0048] The light source excitation module 3 includes N light sources, which are distributed in N lamp positions around the atomization module 2, 2≤N≤4, and each light source is a sharp line light source or a continuous light source. The continuous light source adopts a xenon arc lamp, and the sharp line light source adopts a hollow cathode lamp.

[0049] One light source corresponds to one target element. The present invention can realize the simultaneous detection of 2-4 target elements, including 12 inorganic metal elements such as arsenic (As), antimony (Sb), bismuth (Bi), and mercury (Hg). If one light source is used, any one of the 12 inorganic metal elements can be detected separately.

[0050] The number of electric displacement platforms is the same as the number of light sources. Each light source is installed on a corresponding electric displacement platform. The position and angle of the light source are adjusted by the electric displacement platform, thereby adjusting the atomic fluorescence excitation position of the target element.

[0051] The spectral imaging module includes a spectral signal collection module 4 and a spectral signal processing module 5. The spectral signal collection module 4 is used to expand and receive the atomic fluorescence spectrum of the target element in space for imaging; the spectral signal processing module 5 is used to analyze the imaging data and obtain the concentration of the target element by calculation.

[0052] The spectral signal collection module 4 includes an incident slit 41, a dispersion element 42, and an array position-sensitive anode single photon counting imager 43. The incident slit 41 is used to collimate the atomic fluorescence spectrum of the target element. The dispersion element 42 is used to expand the collimated atomic fluorescence spectrum in space according to the wavelength. The dispersion element 42 adopts a flat-field concave grating to disperse and split the atomic fluorescence spectrum. The array position-sensitive anode single photon counting imager 43 is used to collect the atomic fluorescence spectrum after wavelength expansion. Atomic fluorescence of different wavelengths is collected by different equivalent pixels of the array position-sensitive anode single photon counting imager 43.

[0053] When the optical devices in the spectral signal collection module 4 are fixed, that is, the spectral signal collection module 4 as a whole is fixed, the imaging of the area array position-sensitive anode single-photon counting imaging detector 43 is a slit image formed through the incident slit 41 .

[0054] The present invention installs the spectral signal collection module 4 as a whole on a two-dimensional precision displacement platform, and drives the spectral signal collection module 4 to move as a whole through the two-dimensional precision displacement platform to realize scanning imaging of the incident slit 41, obtain multiple slit images, and finally splice them to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame.

[0055] Due to the charge-coupled device (CCD) and complementary metal oxide semiconductor (CMOS), the detection capability of weak ultraviolet band signals needs to be improved because of the inherent dark current noise. And the typical application field of atomic fluorescence is element trace and ultra-trace detection, and the main spectral signal is distributed in the 180-320nm band, so the existing conventional CCD or CMOS imaging detectors, and even ICCD and EMCCD imaging detectors are not suitable for this type of spectral detection system. Therefore, the present invention adopts a planar position-sensitive anode single photon counting imager 43 as an imaging detector. The surface of the imaging detector is composed of 104~107 mutually parallel microchannel plates (Microchannel Plate, MCP) with secondary electron emission materials coated on the inner wall, and every two pipes form an independent "V" type electron multiplier device. The structure of the anode detector based on MCP is similar to a miniature PMT matrix. The spectrum to be detected is converted into photoelectrons through the photoelectric effect through the photocathode. After the photoelectrons pass through the inner wall of the MCP, they are multiplied to form an electron cloud. Under the action of the electric field, the electron cloud is accelerated to fall on the position-sensitive anode. The position-sensitive anode obtains the center position of the multiplied electron cloud through a certain position decoding principle, and then inputs it into the computer for decoding and imaging through subsequent processing circuits.

[0056] The spectral signal processing module 5 includes an imaging splicing unit, an atomic fluorescence spectrum line recognition unit and a light source adjustment unit; wherein the imaging splicing unit is used to splice the images of different excitation areas of the argon-hydrogen flame to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame; the atomic fluorescence spectrum line recognition unit is used to determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectral image; if so, the position and angle of each light source in the light source excitation module are kept unchanged; if not and a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame, the light source adjustment unit According to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, an adjustment instruction is issued to the electric displacement platform, and the electric displacement platform corrects the posture deviation of each light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if the light source scattering interference signal excited by the light source does not appear and appears in the lower half of the argon-hydrogen flame, the light source adjustment unit issues an adjustment instruction to the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, and the electric displacement platform corrects the posture deviation of each light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

[0057] The present invention divides the spectral image into three equal areas from top to bottom, each area occupies 1 / 3 of the size of the spectral image, the top area is used as the upper half area of ​​the argon-hydrogen flame, the middle area is used as the central area of ​​the argon-hydrogen flame, and the bottom area is used as the lower half area of ​​the argon-hydrogen flame.

[0058] The light source scattering interference signal refers to the scattering interference produced by substances such as aerosols and water vapor when the light source excites the atomic fluorescence spectrum.

[0059] The temperature in the upper half and the center of the argon-hydrogen flame is relatively high. Substances such as aerosols and water vapor will be evaporated by the argon-hydrogen flame. The light source scattering interference signal usually exists in the lower half of the argon-hydrogen flame. As long as the position of the light source is adjusted so that the excited atomic fluorescence spectrum converges to the center of the argon-hydrogen flame, the light source scattering interference signal can be avoided from affecting the detection results.

[0060] The above content describes in detail the excitation beam adjustment system for atomic fluorescence dispersion detection provided by the present invention. Corresponding to the excitation beam adjustment system, the present invention also provides an excitation beam adjustment method for atomic fluorescence dispersion detection, which is implemented by using the above excitation beam adjustment system and specifically includes the following steps:

[0061] S1: The sample to be tested is sent into the excitation beam adjustment system for excitation, and the atomic fluorescence spectrum excited by the target element in the sample to be tested is collected by different equivalent pixel positions of the area array position-sensitive anode single photon counting imager.

[0062] S2: By controlling the two-dimensional precision displacement platform to adjust the spectral signal collection submodule, different excitation areas of the argon-hydrogen flame are scanned and spliced ​​to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame after splicing.

[0063] S3: Determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectral image; if so, keep the position and angle of the light source in the light source excitation module unchanged; if not and a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame, then the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if not and a light source scattering interference signal excited by the light source appears in the lower half of the argon-hydrogen flame, then the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

[0064] The spectral imaging detection method is used to identify the atomic fluorescence spectrum lines excited by the target elements in the spectral image and the light source scattering interference signals excited by the light source.

[0065] The wavelengths of atomic fluorescence signals and light source scattering interference signals are different, and they can be distinguished through the characteristic spectral line library of different elements (the wavelengths of characteristic spectral lines of different elements are different). The light source scattering interference signal is actually a hill-like band spectral signal of 280-320nm, while the atomic fluorescence signal is a line spectral signal. The wavelength in the spectral image is detected by the spectral imaging detection method to identify the atomic fluorescence signal and the light source scattering interference signal.

[0066] The spectral imaging detection method is used to identify whether the atomic fluorescence spectrum lines excited by the target element appear in the central area of ​​the argon-hydrogen flame.

[0067] The spectral imaging detection method is used to identify whether a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame or the lower half of the argon-hydrogen flame.

[0068] The spectral imaging detection method can be used to obtain the wavelengths of spectral signals distributed in different regions. The region in which the atomic fluorescence signal excited by the target element and the light source scattering interference signal appear in the argon-hydrogen flame can be identified and analyzed by the spectrum and imaging signals. The specific detection method of the spectral imaging detection method is an existing technology, so it will not be repeated here.

[0069] When the excitation beam converges to the center of the argon-hydrogen flame, it is in the best excitation position in the fluorescence excitation area, and there is no need to adjust the position of the light source; when the excitation beam cannot converge to the center of the argon-hydrogen flame, the atomic fluorescence signal obtained cannot reach the best state, which will affect the detection performance and indicators. Therefore, it is necessary to first determine whether the excitation beam is in the center of the argon-hydrogen flame.

[0070] If it is observed through the spectral image that there is no strong atomic fluorescence signal of the target element in the central area of ​​the argon-hydrogen flame, and a small amount of light source scattering interference signal appears in the upper half of the argon-hydrogen flame due to the excitation of the light source, it means that the light source is at a high position and does not irradiate the central area of ​​the argon-hydrogen flame. It is necessary to lower the irradiation position of the light source through the electric displacement platform so that the excitation beam converges to the central area of ​​the argon-hydrogen flame.

[0071] If it is observed through the spectral image that there is no strong atomic fluorescence signal of the target element in the central area of ​​the flame, and a small amount of light source scattering interference signal appears in the lower half of the argon-hydrogen flame due to the excitation of the light source, it means that the light source is in a low position and does not irradiate the central area of ​​the argon-hydrogen flame. It is necessary to raise the irradiation position of the light source through the electric displacement platform so that the excitation beam converges to the central area of ​​the argon-hydrogen flame.

[0072] The present invention adjusts the light source once to form an image, and determines whether the excitation beam of the light source is at the optimal excitation position. If not, it is adjusted again until the excitation beam of the light source converges to the central area of ​​the argon-hydrogen flame.

[0073] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0074] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-photon atomic fluorescence excitation beam adjustment system, comprising a sample injection module, an atomization module and a light source excitation module, wherein the sample injection module is used to feed the sample into the atomization module, the atomization module is used to atomize the target element in the sample to form an argon-hydrogen flame, and the light source excitation module is used to excite the target element to make the electrons outside the nucleus of the target element transition to generate the atomic fluorescence spectrum of the target element; characterized in that: The single-photon-based atomic fluorescence excitation beam adjustment system also includes an electric displacement platform, a two-dimensional precision displacement platform and a spectral imaging module; The electric displacement platform is used to adjust the position and angle of the light source excitation module; The spectral imaging module includes a spectral signal collection submodule and a spectral signal processing submodule; The spectral signal collection submodule includes an incident slit, a dispersion element, and a planar array position-sensitive anode single-photon counting imager. The incident slit is used to collimate the atomic fluorescence spectrum of the target element, the dispersion element is used to expand the collimated atomic fluorescence spectrum in space according to the wavelength, and the planar array position-sensitive anode single-photon counting imager is used to collect the atomic fluorescence spectrum after the wavelength expansion; The two-dimensional precision displacement platform is used to adjust the position of the spectral signal collection submodule to achieve slit scanning imaging; The spectral signal processing submodule includes an imaging splicing unit, an atomic fluorescence spectrum line identification unit, and a light source adjustment unit; The imaging splicing unit is used to splice the spectral imaging of different excitation areas of the argon-hydrogen flame to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame; The atomic fluorescence spectrum line recognition unit is used to determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectrum image; If it occurs, keep the position and angle of the light source in the light source excitation module unchanged; If the light source scattering interference signal excited by the light source does not appear and appears in the upper half of the argon-hydrogen flame, the light source adjustment unit sends an adjustment instruction to the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, and the electric displacement platform corrects the posture deviation of the light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if the light source scattering interference signal excited by the light source does not appear and appears in the lower half of the argon-hydrogen flame, the light source adjustment unit sends an adjustment instruction to the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, and the electric displacement platform corrects the posture deviation of the light source according to the adjustment instruction, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

2. The single-photon atomic fluorescence excitation beam adjustment system according to claim 1, characterized in that: The sampling module includes a carrier gas tank, a sample tank, a reducing agent tank, a peristaltic pump, a reactor, a gas-liquid separator and a waste liquid recovery device. The carrier gas tank is connected to the gas-liquid inlet of the gas-liquid separator through a pipeline, the sample tank and the reducing agent tank are connected to the inlet of the peristaltic pump through a pipeline, the outlet of the peristaltic pump is connected to the inlet of the reactor through a pipeline, the outlet of the reactor is connected to the gas-liquid inlet of the gas-liquid separator through a pipeline, the waste liquid discharge port of the gas-liquid separator is connected to the waste liquid recovery device, and the gas-liquid outlet of the gas-liquid separator is connected to the atomization module through a pipeline.

3. The single-photon atomic fluorescence excitation beam adjustment system according to claim 1 or 2, characterized in that: The atomization module is a flame atomizer.

4. The single-photon atomic fluorescence excitation beam adjustment system according to claim 3 is characterized in that: The light source excitation module includes N light sources distributed on N lamp positions around the atomization module, 2≤N≤4, and each light source is a sharp line light source or a continuous light source.

5. The single-photon atomic fluorescence excitation beam adjustment system according to claim 4, characterized in that: The continuous light source is a xenon arc lamp, and the sharp line light source is a hollow cathode lamp.

6. The single-photon atomic fluorescence excitation beam adjustment system according to claim 4, characterized in that: The number of the electric displacement platforms is the same as the number of the light sources, and each light source is mounted on a corresponding electric displacement platform.

7. A method for adjusting an atomic fluorescence excitation beam based on a single photon, implemented by using the atomic fluorescence excitation beam adjustment system based on a single photon according to any one of claims 1 to 6, characterized in that: The steps include: S1: The sample to be tested is sent into the excitation beam adjustment system for excitation, and the atomic fluorescence spectrum excited by the target element in the sample to be tested is collected by different equivalent pixel positions of the area array position-sensitive anode single photon counting imager; S2: By controlling the two-dimensional precision displacement platform to adjust the spectral signal collection submodule, different excitation areas of the argon-hydrogen flame are scanned and spliced ​​to form a spectral image of the entire excitation area of ​​the argon-hydrogen flame after splicing; S3: Determine whether the atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame in the spectrum image; if so, keep the position and angle of the light source in the light source excitation module unchanged; If the light source scattering interference signal excited by the light source does not appear and appears in the upper half of the argon-hydrogen flame, the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if the light source scattering interference signal excited by the light source does not appear and appears in the lower half of the argon-hydrogen flame, the position deviation of the light source is corrected through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

8. The method for adjusting the single-photon atomic fluorescence excitation beam according to claim 7, characterized in that: The spectral image is divided into the upper half of the argon-hydrogen flame, the central area of ​​the argon-hydrogen flame, and the lower half of the argon-hydrogen flame from top to bottom; The spectral imaging detection method is used to identify the atomic fluorescence spectrum lines excited by the target element in the spectral image and the light source scattering interference signal excited by the light source; The spectral imaging detection method is used to identify whether the atomic fluorescence spectrum lines excited by the target element appear in the central area of ​​the argon-hydrogen flame; The spectral imaging detection method is used to identify whether a light source scattering interference signal excited by the light source appears in the upper half of the argon-hydrogen flame or the lower half of the argon-hydrogen flame.

9. The method for adjusting the single-photon atomic fluorescence excitation beam according to claim 8, characterized in that: If no atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame and a light source scattering interference signal excited by the light source appears in the upper area of ​​the argon-hydrogen flame, the irradiation position of the light source is lowered through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame; if no atomic fluorescence spectrum line excited by the target element appears in the central area of ​​the argon-hydrogen flame and a light source scattering interference signal excited by the light source appears in the lower area of ​​the argon-hydrogen flame, the irradiation position of the light source is raised through the electric displacement platform according to the imaging data relationship between the central area of ​​the argon-hydrogen flame and the light source scattering interference signal, so that the excitation light beam converges to the central area of ​​the argon-hydrogen flame.

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