Single-Photon-Based AFS Dispersion Detection System and Its Detection Method

Abstract

The present invention relates to the technical field of atomic fluorescence detection, and particularly to a single-photon-based AFS dispersion detection system and its detection method. The detection system includes a sample injection module, an atomization module, a light source excitation module, a spectral signal collection module, and a spectral signal processing module. The sample injection module is used to send the 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 generate the atomic fluorescence spectrum line of the target element, the spectral signal collection module is used to expand and receive the atomic fluorescence spectrum line of the target element in space for imaging, and the spectral signal processing module is used to analyze the imaging data and obtain the concentration of the target element by calculation. The spectral signal collection module includes an incident slit, a dispersion element, and a matrix position-sensitive anode single-photon counting imaging detector. The present invention can resolve spectral interference signals and directly deduct them during the detection process.

Description

Technical Field

[0001] The present invention belongs to the technical field of atomic fluorescence detection, and particularly relates to a single-photon-based AFS dispersion detection system and a detection method thereof. Background Art

[0002] China is a major country in the application of atomic fluorescence (Atomic Fluorescence Spectrometry, AFS). AFS instruments have become important conventional detection instruments and are widely used in environmental detection, food hygiene, water quality detection and other fields; Instrument products based on the combined technology of hydride generation method and atomic fluorescence spectrometry (Hydride generation-Atomic Fluorescence Spectrometry, HG-AFS) can effectively detect and analyze 12 inorganic metal elements such as arsenic (As), antimony (Sb), bismuth (Bi), mercury (Hg), etc., and have the advantages of small matrix interference and high sensitivity.

[0003] Existing AFS instruments mainly use dispersion detection methods to achieve atomic fluorescence detection. The dispersion detection methods include filter wavelength selection method, rotating grating single-channel scanning method and array detector full-spectrum direct reading method. According to the type of dispersion detection method, AFS instruments are divided into filter wavelength selection type detection system, rotating grating single-channel scanning type detection system and array detector full-spectrum direct reading type detection system. The filter wavelength selection type detection system using the dispersion detection method of multiple filter replacements is difficult to meet the requirements of simultaneous and rapid detection of multiple elements; The rotating grating single-channel scanning type detection system has a large volume and a long optical path, which will cause obvious attenuation of the fluorescence signal intensity, affect the detection sensitivity, and the system structure is relatively complex, containing mechanical transmission components, and the detection speed is slow; The array detector full-spectrum direct reading type detection system usually uses CCD or CMOS to directly detect the scattered spectrum, but its application in the AFS detection field is limited due to its insufficient ability to detect weak ultraviolet signals.

[0004] In view of the development needs of existing AFS instruments, an AFS spectral detection system is proposed, which uses a digital micromirror device (DMD) as a spatial light modulator, a grating as a spectroscope, and a PMT as a detector. Since the PMT does not have the ability to select spectra, it is necessary to control the flipping of the micromirror array of the DMD to achieve wavelength selection. However, existing commercial DMDs need to use ultraviolet enhancement methods such as window replacement to achieve spatial light modulation of spectra below 270nm. Therefore, the AFS spectral detection system is not suitable for ultraviolet spectral detection.

[0005] None of the above-mentioned AFS instruments can detect spectral signals in different bands simultaneously or can only detect partial spectral data each time, and cannot measure the excited fluorescence and spectral interference simultaneously. Summary of the Invention

[0006] In view of this, the present invention aims to provide a single-photon-based AFS dispersion detection system and its detection method to solve the technical problems that the prior art cannot detect spectral signals in different bands simultaneously or can only detect partial spectral data each time, and cannot measure the excited fluorescence and spectral interference simultaneously.

[0007] To achieve the above object, the technical solution of the present invention is realized as follows:

[0008] A single-photon-based AFS dispersion detection system includes a sample injection module, an atomization module, and a light source excitation module. The sample injection module is used to send the sample into the atomization module, the atomization module is used to atomize the sample, and the light source excitation module is used to excite the sample to cause the outer electrons of the target element in the sample to be excited and transition, generating the atomic fluorescence spectrum line of the target element. It is characterized in that the single-photon-based AFS dispersion detection system further includes a spectral signal collection module and a spectral signal processing module; wherein,

[0009] The spectral signal collection module includes an incident slit, a dispersion element, and a planar position-sensitive anode single-photon counting imaging detector. The incident slit is used to collimate the atomic fluorescence spectrum line of the target element, the dispersion element is used to expand the collimated atomic fluorescence spectrum line in space according to the wavelength, and the planar position-sensitive anode single-photon counting imaging detector is used to collect the atomic fluorescence spectrum line after wavelength expansion.

[0010] The spectral signal processing module includes an equivalent pixel coordinate acquisition unit, a scattering interference signal acquisition unit, a correspondence determination unit, a scattering interference spectral database establishment unit, a target element atomic fluorescence spectrum line set establishment unit, a target element non-interference atomic fluorescence spectrum line set acquisition unit, a target element test standard curve drawing unit, a photon count total value acquisition unit, and a target element concentration calculation unit; wherein,

[0011] The equivalent pixel coordinate acquisition unit is used to acquire the equivalent pixel coordinates formed by the electron cloud emerging from the microchannel plate position at the current moment t0 when a blank sample without elements is sent into the single-photon-based AFS dispersion detection system. The equivalent pixel coordinates (X t0 Y t0 ) are calculated as follows:

[0012] ;

[0013] ;

[0014] In the formula, C represents the capacitance per unit area of the microchannel plate, k represents the interelectrode modulation coefficient, L represents the diameter of the microchannel plate, I and V respectively represent current and voltage, and respectively represent the coordinate deviations of the electron cloud clusters in the x and y directions, and represent the charge coefficient;

[0015] The correspondence determination unit is used to collect the atomic fluorescence spectra of the scattered interference signals within the time T m analyze the distribution of the scattered interference signals at the positions corresponding to the atomic fluorescence of different wavelengths, and determine the relationship between the equivalent pixel coordinates and the scattered interference signals;

[0016] The scattered interference spectrum database establishment unit is used to establish a scattered interference spectrum database according to the relationship between the equivalent pixel coordinates and the scattered interference signals , the scattered interference spectrum database is:

[0017] ;

[0018] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the scattered interference signals;

[0019] The target element atomic fluorescence spectrum set establishment unit is used to obtain the positional relationship between the atomic fluorescence spectra and the equivalent pixel coordinates excited by different concentrations of the target element in each test sample when performing atomic fluorescence excitation on each test sample containing different concentrations of the target element, and establish a target element atomic fluorescence spectrum set F , the target element atomic fluorescence spectrum set F is:

[0020] F ;

[0021] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectrum of the target element;

[0022] The target element non-interference atomic fluorescence spectrum set acquisition unit is used to confirm the intersection between the target element atomic fluorescence spectrum set F and the scattered interference spectrum database , and remove this intersection from the target element atomic fluorescence spectrum set F to obtain a target element non-interference atomic fluorescence spectrum set P that is not interfered by the scattered interference signals , the target element non-interference atomic fluorescence spectrum set P that is not interfered by the scattered interference signals is:

[0023] P ;

[0024] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target elements that are not interfered by the scattered interference signals;

[0025] The target element test standard curve drawing unit is used to record the total photon count obtained by different concentrations of the target element in each test sample within Tm time as the signal intensity, and draw the target element test standard curve according to the relationship between the concentration of the target element and the signal intensity;

[0026] The total photon count value acquisition unit is used to perform atomic fluorescence excitation on the actual sample containing the target element with unknown concentration, based on the set of non-interfering atomic fluorescence spectral lines P of the target element , and obtain the total photon count value V of the target element in the actual sample within Tm time that is not interfered by the scattered interference signal t ;

[0027] The target element concentration calculation unit is used to substitute the total photon count value V t into the target element test standard curve, and calculate the concentration of the target element in the actual sample according to the relationship between the concentration and the signal intensity.

[0028] Furthermore, the sample injection 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.

[0029] Furthermore, the atomization module is a flame atomizer.

[0030] Furthermore, the light source excitation module includes N light sources, which are 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.

[0031] Furthermore, the continuous light source uses a xenon arc lamp, and the sharp-line light source uses a hollow cathode lamp.

[0032] A single-photon-based AFS dispersion detection method, which is realized by using the above-mentioned single-photon-based AFS dispersion detection system, includes the following steps:

[0033] S1: Feed a blank sample without elements into the single-photon-based AFS dispersion detection system, and the atomic fluorescence spectral lines of the scattering interference signals are collected at different equivalent pixel positions of the area array position-sensitive anode single-photon counting imaging detector;

[0034] S2: Obtain the equivalent pixel coordinates formed by the electron cloud emerging from the microchannel plate position at the current moment t0. The calculation formula for the equivalent pixel coordinates (X t0 Y t0 ) is as follows:

[0035] ;

[0036] ;

[0037] In the formula, C represents the capacitance per unit area of the microchannel plate, k represents the interelectrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent current and voltage respectively, and represent the coordinate deviation values of the electron cloud in the x-direction and y-direction respectively, and represent the charge coefficients;

[0038] S3: Collect the atomic fluorescence spectral lines of the scattering interference signals within time T m , analyze the distribution of the scattering interference signals at the positions corresponding to the atomic fluorescence of different wavelengths, and determine the relationship between the equivalent pixel coordinates and the scattering interference signals;

[0039] S4: Establish a scattering interference spectral database according to the relationship between the equivalent pixel coordinates and the scattering interference signals. The scattering interference spectral database is:

[0040] ;

[0041] In the formula, ~ represent the equivalent pixel coordinates corresponding to the scattering interference signals respectively;

[0042] S5: Feed each test sample containing different concentrations of the target element into the single-photon-based AFS dispersion detection system in sequence for excitation, obtain the positional relationship between the atomic fluorescence spectral lines and the equivalent pixel coordinates excited by different concentrations of the target element in each test sample, and establish a set F of the atomic fluorescence spectral lines of the target element. The set F of the atomic fluorescence spectral lines of the target element is:

[0043] F ;

[0044] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target element;

[0045] S6: Confirm the set F of atomic fluorescence spectral lines of the target element and the scattered interference spectral database and remove the intersection from the set F of atomic fluorescence spectral lines of the target element to obtain the set P of atomic fluorescence spectral lines of the target element that is not interfered by the scattered interference signal, the set P of atomic fluorescence spectral lines of the target element that is not interfered by the scattered interference signal is:

[0046] P ;

[0047] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target element that are not interfered by the scattered interference signal;

[0048] S7: Record the total photon count obtained by different concentrations of the target element in each test sample within Tm time as the signal intensity, and draw the test standard curve of the target element according to the relationship between the concentration of the target element and the signal intensity;

[0049] S8: Send the actual sample containing the target element with unknown concentration into the AFS dispersion detection system based on single photons for excitation, and obtain the total photon count value V of the target element in the actual sample without being interfered by the scattered interference signal within Tm time t ;

[0050] S9: Substitute the total photon count value V t into the test standard curve of the target element, and obtain the concentration of the target element in the actual sample according to the relationship between the concentration and the signal intensity.

[0051] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0052] (1) Through the dispersion method, the fluorescence signal and the spectral interference signal can be distinguished by different equivalent pixel positions of the detector, the spectral interference signal can be directly deducted, and the intensity of the target spectral signal can be directly accumulated. There is no need to analyze the spectral signals in the entire spectral band, effectively improving the detection efficiency.

[0053] (2) For the atomic fluorescence signal of the target element that overlaps with the spectral interference region, the present invention can directly deduct the intensity of the spectral interference signal in the detection result to obtain the fluorescence signal that is not affected by the spectral interference.

[0054] (3) The present invention uses a planar position-sensitive anode single-photon counting imaging detector, which can collect fluorescence signals and spectral interferences that appear simultaneously during a single detection process, avoiding the uncertainty in the accuracy of detection results caused by time-division multiplexing in traditional methods. Description of the Drawings

[0055] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0056] Figure 1 It is a schematic structural diagram of a single-photon-based AFS dispersion detection system according to an embodiment of the present invention;

[0057] Figure 2 It is a schematic diagram of multiple atomic fluorescence spectral lines of four target elements according to an embodiment of the present invention;

[0058] Figure 3 It is a schematic diagram of three atomic fluorescence spectral lines of element A according to an embodiment of the present invention;

[0059] Figure 4 It is a schematic diagram of the relationship between the spectral signal intensities formed by one atomic fluorescence spectral line of element A according to an embodiment of the present invention;

[0060] Figure 5 It is a schematic diagram of the test standard curve of element A according to an embodiment of the present invention;

[0061] Figure 6 It is a schematic diagram of the test standard curves of elements A, B, C, and D according to an embodiment of the present invention.

[0062] Description of the Reference Numerals:

[0063] Sampling 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, planar position-sensitive anode single-photon counting imaging detector 43, spectral signal processing module 5. Detailed Embodiments

[0064] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0065] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0066] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is 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 should not be construed as a limitation to 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 specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0067] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0068] Next, reference will be made to the attached Figure 1 - attached Figure 6 and in combination with the embodiments to detail the present invention.

[0069] As Figure 1 shown, the single-photon-based AFS dispersion detection system provided by the embodiment of the present invention includes a sample introduction module 1, an atomization module 2, a light source excitation module 3, a spectral signal collection module 4, and a spectral signal processing module 5. Among them, the sample introduction module 1 is used to send the sample into the atomization module; the atomization module 2 is used to atomize the sample; the light source excitation module 3 is used to excite the sample to cause the outer electrons of the target element in the sample to be excited and transition, generating the atomic fluorescence spectrum line of the target element; the spectral signal collection module 4 is used to expand and receive the atomic fluorescence spectrum line 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 through calculation.

[0070] The sample injection 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. Among them, the carrier gas tank 11 is connected to the gas-liquid inlet of the gas-liquid separator 15 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 15 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 2 through a pipeline.

[0071] 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 for reaction, generating hydrides and hydrogen of the target elements contained in the sample, and entering the gas-liquid separator 16 under the propulsion of the carrier gas to separate the water vapor in the sample, and then entering the atomization module 2.

[0072] The atomization module 2 uses a flame atomizer. After high-temperature treatment by the flame atomizer, the target elements to be measured in the sample are atomized and an argon-hydrogen flame is formed.

[0073] The light source excitation module 3 includes N light sources, which are distributed on N lamp positions around the atomization module 2, where 2 ≤ N ≤ 4, and each light source is a sharp-line light source or a continuous light source.

[0074] Furthermore, the continuous light source uses a xenon arc lamp, and the sharp-line light source uses a hollow cathode lamp.

[0075] One light source corresponds to one target element. The present invention can realize the simultaneous detection of 2-4 target elements. The target elements include 12 inorganic metal elements such as arsenic (As), antimony (Sb), bismuth (Bi), mercury (Hg), etc. If one light source is to be used, any one of the 12 inorganic metal elements can be detected separately.

[0076] The spectral signal collection module 4 includes an incident slit 41, a dispersion element 42, and a matrix position-sensitive anode single-photon counting imaging detector 43. The incident slit 41 is used to collimate the atomic fluorescence spectrum line of the target element. The dispersion element 42 is used to expand the collimated atomic fluorescence spectrum line in space according to the wavelength. The dispersion element 42 uses a flat-field concave grating to disperse and spectrally analyze the atomic fluorescence spectrum line. The matrix position-sensitive anode single-photon counting imaging detector 43 is used to collect the atomic fluorescence spectrum line after wavelength expansion, and the atomic fluorescence of different wavelengths is collected by different equivalent pixels of the matrix position-sensitive anode single-photon counting imaging detector 43.

[0077] During detection, each optical device in the spectral signal collection module 4 is fixed, that is, the spectral signal collection module 4 as a whole is fixed. The image formed by the area array position-sensitive anode single-photon counting imaging detector 43 is a slit image formed through the incident slit 41.

[0078] Due to Charge-coupled device (CCD) and Complementary metal oxide semiconductor (CMOS), but they have relatively large inherent dark current noise, and their detection ability for weak ultraviolet band signals needs to be improved. And the typical application field of atomic fluorescence is trace and ultra-trace element detection, and the main spectral signals are distributed in the 180 - 320 nm band. Therefore, existing conventional CCD or CMOS imaging detectors, even imaging detectors such as ICCD and EMCCD, are not suitable for this type of spectral detection system. So, the present invention uses the area array position-sensitive anode single-photon counting imaging detector 43 as the imaging detector. The surface of this imaging detector is composed of 104 - 107 microchannel plates (MCPs) with their inner walls coated with secondary electron emission materials and parallel to each other. Each two channels form an independent "V"-type electron multiplication device. The anode detector structure based on MCP is similar to a micro PMT matrix. The spectral to be detected is converted into photoelectrons through the photoelectric effect by the photocathode. After passing through the inner wall of the MCP, the photoelectrons are multiplied to form an electron cloud. Under the action of the electric field, the electron cloud accelerates and falls 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 is input into a computer through the subsequent processing circuit for decoding and imaging.

[0079] The spectral signal processing module 5 includes an equivalent pixel coordinate acquisition unit, a scattered interference signal acquisition unit, a correspondence determination unit, a scattered interference spectral database establishment unit, a target element atomic fluorescence spectral line set establishment unit, a target element non-interference atomic fluorescence spectral line set acquisition unit, a target element test standard curve drawing unit, a photon counting total value acquisition unit, and a target element concentration calculation unit.

[0080] The equivalent pixel coordinate acquisition unit is used to obtain the equivalent pixel coordinates formed by the electron cloud emerging from the microchannel plate position at the current moment t0 when a blank sample without elements is sent into the single-photon-based AFS dispersion detection system. The calculation formula for the equivalent pixel coordinates (X t0 Y t0 ) is as follows:

[0081] ;

[0082] ;

[0083] In the formula, C represents the capacitance per unit area of the microchannel plate, k represents the interelectrode modulation coefficient, L represents the diameter of the microchannel plate, I and V respectively represent current and voltage, and respectively represent the coordinate deviations of the electron cloud clusters in the x and y directions, and represent the charge coefficient.

[0084] The correspondence determination unit is used to collect the atomic fluorescence spectral lines excited by the blank sample within T m time, analyze the distribution of the scattered interference signals at the corresponding positions of the atomic fluorescence at different wavelengths, and determine the relationship between the equivalent pixel coordinates and the scattered interference signals.

[0085] The scattered interference spectral database establishment unit is used to establish a scattered interference spectral database according to the relationship between the equivalent pixel coordinates and the scattered interference signals , the scattered interference spectral database is:

[0086] ;

[0087] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the scattered interference signals, is the coordinate of the starting position point in the scattered interference spectral database, is the coordinate of the ending position point in the scattered interference spectral database.

[0088] The target element atomic fluorescence spectral line set establishment unit is used to obtain the positional relationship between the atomic fluorescence spectral lines and the equivalent pixel coordinates excited by different concentrations of the target element in each test sample when performing atomic fluorescence excitation on each test sample containing different concentrations of the target element, and establish a target element atomic fluorescence spectral line set F , the target element atomic fluorescence spectral line set F is:

[0089] F ;

[0090] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the target element atomic fluorescence spectral lines, is the coordinate of the starting position point in the target element atomic fluorescence spectral line set, is the coordinate of the ending position point in the target element atomic fluorescence spectral line set.

[0091] The target element non-interference atomic fluorescence spectral line set acquisition unit is used to confirm the target element atomic fluorescence spectral line set F and the intersection with the scattered interference spectral database is removed from the target element atomic fluorescence spectral line set F to obtain the target element non-interference atomic fluorescence spectral line set P that is not interfered by the scattered interference signal The target element non-interference atomic fluorescence spectral line set P that is not interfered by the scattered interference signal is:

[0092] P ;

[0093] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target element that are not interfered by the scattered interference signal, is the starting position point coordinate in the target element non-interference atomic fluorescence spectral line set that is not interfered by the scattered interference signal, is the ending position point coordinate in the target element non-interference atomic fluorescence spectral line set that is not interfered by the scattered interference signal.

[0094] The target element test standard curve drawing unit is used to record the total photon count obtained by different concentrations of the target element in each test sample within Tm time as the signal intensity, and draw the target element test standard curve according to the relationship between the concentration of the target element and the signal intensity.

[0095] The total photon count value acquisition unit is used to, when performing atomic fluorescence excitation on the actual sample containing the target element, based on the target element non-interference atomic fluorescence spectral line set P obtain the total photon count value V of the target element in the actual sample within Tm time that is not interfered by the scattered interference signal t .

[0096] The target element concentration calculation unit is used to substitute the total photon count value V t into the target element test standard curve, and calculate the concentration of the target element in the actual sample according to the relationship between the concentration and the signal intensity.

[0097] The above content details the single-photon-based AFS dispersion detection system provided by the present invention. Corresponding to the single-photon-based AFS dispersion detection system, the present invention also provides a single-photon-based AFS dispersion detection method, which is implemented by using the above single-photon-based AFS dispersion detection system, and specifically includes the following steps:

[0098] S1: Send the blank sample without elements into the single-photon-based AFS dispersion detection system, and the atomic fluorescence spectral lines of the scattered interference signal are collected by different equivalent pixel positions of the area array position-sensitive anode single-photon counting imaging detector.

[0099] A blank sample refers to a sample without elements, which only contains a carrier solution. By testing the blank sample, the distribution position of the scattering interference signal can be determined.

[0100] S2: Obtain the equivalent pixel coordinates formed by the electron cloud emerging from the position of the microchannel plate at the current moment t0. The calculation formula for the equivalent pixel coordinates (X t0 Y t0 ) is as follows:

[0101] ;

[0102] ;

[0103] In the formula, C represents the capacitance per unit area of the microchannel plate, k represents the interelectrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent current and voltage respectively, and represent the coordinate deviation values of the electron cloud in the x - direction and y - direction respectively, and represent the charge coefficients.

[0104] S3: Collect the atomic fluorescence spectral lines of the scattering interference signal within time T m , analyze the distribution of the scattering interference signal at the positions corresponding to the atomic fluorescence of different wavelengths, and determine the relationship between the equivalent pixel coordinates and the scattering interference signal.

[0105] S4: Establish a scattering interference spectral database according to the relationship between the equivalent pixel coordinates and the scattering interference signal , and the scattering interference spectral database is:

[0106] ;

[0107] In the formula, ~ represent the equivalent pixel coordinates corresponding to the scattering interference signal respectively, is the coordinate of the starting position point in the scattering interference spectral database, is the coordinate of the ending position point in the scattering interference spectral database.

[0108] When the blank sample is sent into the single - photon - based AFS dispersion detection system, no spectral signal will be excited. If a spectral signal is detected during the detection of the blank sample, the detected spectral signal is considered as a scattering interference signal, and its distribution can be obtained through coordinates.

[0109] S5: Sequentially send each test sample containing the target element at different concentrations into the single-photon-based AFS dispersion detection system for excitation, obtain the positional relationship between the atomic fluorescence spectral lines and the equivalent pixel coordinates excited by the target element at different concentrations in each test sample, and establish the atomic fluorescence spectral line set F of the target element , the atomic fluorescence spectral line set F of the target element is:

[0110] F ;

[0111] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target element, is the coordinate of the starting position point in the atomic fluorescence spectral line set of the target element, is the coordinate of the ending position point in the atomic fluorescence spectral line set of the target element.

[0112] The test sample is a sample containing the target element, and the concentration of the target element is known. Sending multiple test samples containing the target element at different concentrations into the single-photon-based AFS dispersion detection system can excite atomic fluorescence signals of different intensities.

[0113] Figure 2 shows the positional relationship of the equivalent pixel coordinates of the different atomic fluorescence spectral lines of four target elements, namely element A, element B, element C, and element D, on the area array position-sensitive anode single-photon counting imaging detector.

[0114] As Figure 2 shown, for the multiple atomic fluorescence spectral lines spectrally imaged by the flat-field concave grating for the four target elements, the wavelengths of the atomic fluorescence spectral lines excited by different target elements correspond to different equivalent pixel positions on the area array position-sensitive anode single-photon counting imaging detector, and the depth indicates the signal strength.

[0115] Figure 3 shows three atomic fluorescence spectral lines of element A.

[0116] As Figure 3 shown, the analysis of the atomic fluorescence spectral lines of element A can obtain the positional relationship between each spectral signal spectrally dispersed by the flat-field concave grating and the equivalent pixel coordinates.

[0117] Figure 4 shows the spectral signal intensity relationship formed by one atomic fluorescence spectral line of element A.

[0118] As Figure 4 shown, by obtaining the spectral intensity correspondence relationship through the signal count value at the equivalent pixel position of the area array position-sensitive anode single-photon counting imaging detector, the spectral peak on the Figure 4 left can be generated.

[0119] S6: Confirm the atomic fluorescence spectral line set F of the target element and the scattering interference spectral database to find their intersection, and remove this intersection from the atomic fluorescence spectral line set F of the target element to obtain the atomic fluorescence spectral line set P of the target element that is not interfered by the scattering interference signal The atomic fluorescence spectral line set P of the target element that is not interfered by the scattering interference signal is as follows:

[0120] P ;

[0121] In the formula, ~ respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectral lines of the target element that are not interfered by the scattering interference signal, is the coordinate of the starting position point in the non-interference atomic fluorescence spectral line set of the target element that is not interfered by the scattering interference signal, is the coordinate of the ending position point in the non-interference atomic fluorescence spectral line set of the target element that is not interfered by the scattering interference signal.

[0122] S7: Record the total photon count obtained for different concentrations of the target element in each test sample within Tm time as the signal intensity, and plot the test standard curve of the target element based on the relationship between the concentration of the target element and the signal intensity.

[0123] Figure 5 shows the test standard curves for the concentration of element A from concentration 1 to concentration 4.

[0124] The present invention can simultaneously measure multiple target elements. For example, it can simultaneously measure element A, element B, element C, and element D. The test standard curves for the four target elements are as Figure 6 shown.

[0125] S8: Feed the actual sample containing the target element with unknown concentration into the single-photon-based AFS dispersion detection system for excitation to obtain the total photon count value V of the target element in the actual sample without being interfered by the scattering interference signal within Tm time t .

[0126] The actual sample refers to a sample containing the same target element as the test sample, but the concentration of the target element is unknown.

[0127] Obtain the total photon count value V of the target element in the actual sample without being interfered by the scattering interference signal within Tm time according to steps S1 - S6 t .

[0128] S9: The total photon count value V tBring the test standard curve of the target element, and obtain the concentration of the target element in the actual sample according to the relationship between the concentration and the signal intensity.

[0129] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0130] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A single-photon based AFS dispersion detection 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 sample, and the light source excitation module is used to excite the sample to make the electrons outside the nuclei of the target element in the sample excited and transitioned to generate the atomic fluorescence spectrum of the target element; characterized in that: The single-photon based AFS dispersion detection system also includes a spectral signal collection module and a spectral signal processing module; wherein, The spectral signal collection module includes an incident slit, a dispersion element, and a planar array position-sensitive anode single-photon counting imaging detector. 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 imaging detector is used to collect the atomic fluorescence spectrum after the wavelength is expanded; The spectral signal processing module includes an equivalent pixel coordinate acquisition unit, a scattering interference signal acquisition unit, a corresponding relationship determination unit, a scattering interference spectrum database establishment unit, a target element atomic fluorescence spectrum line set establishment unit, a target element non-interference atomic fluorescence spectrum line set acquisition unit, a target element test standard curve drawing unit, a photon count sum value acquisition unit and a target element concentration calculation unit; wherein, The equivalent pixel coordinate acquisition unit is used to obtain the equivalent pixel coordinates formed by the electron cloud emitted from the position of the microchannel plate at the current time t0 when a blank sample without elements is sent to the AFS dispersion detection system based on single photons. The equivalent pixel coordinates (X t0 Y t0 ) is calculated as follows: ； ； In the formula, C represents the capacitance per unit area of ​​the microchannel plate, k represents the inter-electrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent the current and voltage respectively. and Respectively represent the electron cloud coordinate deviation values ​​in the x-direction and y-direction, and represents the charge coefficient; The corresponding relationship determination unit is used to determine T m The atomic fluorescence spectrum of the scattered interference signal within a certain time period is collected, the distribution of the scattered interference signal at the position corresponding to the atomic fluorescence of different wavelengths is analyzed, and the relationship between the equivalent pixel coordinates and the scattered interference signal is determined; The scattered interference spectrum database establishment unit is used to establish a scattered interference spectrum database according to the relationship between the equivalent pixel coordinates and the scattered interference signal. , scattering interference spectrum database for: ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the scattered interference signals; The target element atomic fluorescence spectrum line set establishment unit is used to obtain the positional relationship between the atomic fluorescence spectrum lines excited by the target elements of different concentrations in each test sample and the equivalent pixel coordinates when performing atomic fluorescence excitation on each test sample containing the target elements of different concentrations, and establish the target element atomic fluorescence spectrum line set F , target element atomic fluorescence spectrum set F for: F ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectrum lines of the target elements; The target element non-interference atomic fluorescence spectrum line set acquisition unit is used to confirm the target element atomic fluorescence spectrum line set F Interference spectroscopy database with scattering The intersection between the target element atomic fluorescence spectrum set F The non-interfering atomic fluorescence spectrum line set P of the target element that is not interfered by the scattering interference signal is obtained. , the non-interfering atomic fluorescence spectrum line set P of the target element that is not interfered by the scattered interference signal for: P ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectrum of the target element that is not interfered by the scattered interference signal; The target element test standard curve drawing unit is used to record the total photon counts obtained by the target element of different concentrations in each test sample within the Tm time as the signal intensity, and draw the target element test standard curve according to the relationship between the concentration of the target element and the signal intensity; The photon count sum value acquisition unit is used to perform atomic fluorescence excitation on an actual sample containing a target element of unknown concentration based on the non-interfering atomic fluorescence spectrum line set P of the target element. , obtain the total photon count value V of the target element in the actual sample within the Tm time without interference from the scattered interference signal t ; The target element concentration calculation unit is used to convert the total photon count value V t Bring in the target element test standard curve, and calculate the concentration of the target element in the actual sample based on the relationship between concentration and signal intensity.

2. The single-photon based AFS dispersion detection 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 based AFS dispersion detection system according to claim 1 or 2, characterized in that: The atomization module is a flame atomizer.

4. The single-photon based AFS dispersion detection system according to claim 3, 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 based AFS dispersion detection 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. A single-photon based AFS dispersion detection method, implemented using the single-photon based AFS dispersion detection system according to any one of claims 1 to 5, characterized in that: The steps include: S1: A blank sample without elements is sent into the single-photon based AFS dispersion detection system, and the atomic fluorescence spectrum of the scattered interference signal is collected by different equivalent pixel positions of the array position-sensitive anode single-photon counting imaging detector; S2: Obtain the equivalent pixel coordinates formed by the electron cloud emitted from the microchannel plate position at the current time t0. The equivalent pixel coordinates (X t0 Y t0 ) is calculated as follows: ； ； In the formula, C represents the capacitance per unit area of ​​the microchannel plate, k represents the inter-electrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent the current and voltage respectively. and Respectively represent the electron cloud coordinate deviation values ​​in the x-direction and y-direction, and represents the charge coefficient; S3: To T m The atomic fluorescence spectrum of the scattered interference signal within a certain time period is collected, the distribution of the scattered interference signal at the position corresponding to the atomic fluorescence of different wavelengths is analyzed, and the relationship between the equivalent pixel coordinates and the scattered interference signal is determined; S4: Establish a scattering interference spectrum database based on the relationship between equivalent pixel coordinates and scattering interference signals , scattering interference spectrum database for: ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the scattered interference signals; S5: Send each test sample containing target elements of different concentrations into the single-photon based AFS dispersion detection system for excitation, obtain the positional relationship between the atomic fluorescence spectrum lines excited by target elements of different concentrations in each test sample and the equivalent pixel coordinates, and establish the target element atomic fluorescence spectrum line set F , target element atomic fluorescence spectrum set F for: F ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectrum lines of the target elements; S6: Confirm the target element atomic fluorescence spectrum line set F Interference Spectrum Database with Scattering The intersection between the target element atomic fluorescence spectrum set F The target element atomic fluorescence spectrum line set P is obtained without interference from scattered interference signals. , the target element atomic fluorescence line set P is not interfered by the scattered interference signal for: P ； In the formula, ~ They respectively represent the equivalent pixel coordinates corresponding to the atomic fluorescence spectrum of the target element that is not interfered by the scattered interference signal; S7: The total photon counts obtained within the Tm time for the target element of different concentrations in each test sample are recorded as the signal intensity, and a target element test standard curve is drawn according to the relationship between the concentration of the target element and the signal intensity; S8: Send the actual sample containing the target element of unknown concentration into the single-photon based AFS dispersion detection system for excitation, and obtain the total photon count value V of the target element in the actual sample within the Tm time without interference from the scattering interference signal t ; S9: The total photon count value V t Bring in the target element test standard curve and obtain the concentration of the target element in the actual sample based on the relationship between concentration and signal intensity.

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