A detection method for detecting content of chemical elements by using flame photometric spectral curve

Abstract

A detection method for detecting chemical element content by using flame photometric spectral curve, comprising data preparation and detection steps, the data preparation comprises: obtaining standard spectral constant matrix containing all to-be-detected chemical elements by experimental measurement; the detection step comprises: S1. finding maximum light intensity value point in input light intensity matrix; S2. checking whether wavelength value belongs to characteristic wavelength value, yes, entering step S4, otherwise, entering step S3; S3. discarding maximum light intensity value point and re-performing step S1; S4. determining chemical element type according to characteristic wavelength value and calculating concentration value; S5. obtaining intermediate matrix; S6. judging whether intermediate matrix meets continuous detection condition, yes, continuously repeating steps S1-S5 until not meeting continuous detection condition, and terminating process. The present application can complete single compound and mixture analysis and detection.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry technology, and relates to detection technology, specifically a detection method for detecting the content of chemical elements using flame photometric spectral curves. Background Technology

[0002] Detecting sulfur, phosphorus, nitrogen, arsenic, and chlorine-containing poisons using flame photometry is a new technology in poison detection. Previously, flame photometry instruments primarily focused on detecting sulfur and phosphorus poisons. These instruments utilized the characteristic wavelengths of the flame generated when sulfur and phosphorus molecules burn and decompose in a hydrogen flame. The light signals were then converted into electrical signals via a dual-channel system, filtered, and converted into electrical signals. These signals were then processed by a microprocessor system to determine the type and concentration of the poison.

[0003] The existing technology has the following drawbacks: First, a single filter can only detect one type of toxic substance, and the detection of mixtures must be performed using multiple channels or by constantly changing filters; second, the "characteristic spectral lines" are not unique to any particular substance, and many substances may also emit light at the characteristic spectral lines of a certain toxic substance, albeit at lower intensities. When the concentration of non-target compounds is high, false alarms may occur. Summary of the Invention

[0004] To overcome the technical defects of the existing technology, this invention discloses a detection method for detecting the content of chemical elements using flame photometric spectral curves.

[0005] The detection method for determining the content of chemical elements using flame photometric spectroscopy curves as described in this invention includes data preparation, detection steps, and a derived formula for detecting the content of chemical elements. The data preparation includes:

[0006] The standard spectral constant matrix K = [K] containing all the chemical elements to be tested was obtained through experimental measurement. ij ], K ij The subscript i represents different chemical elements, and the subscript j represents different wavelengths λ1, λ2, ... λ. n n is the number of test cases, K ij Let be a constant relating the light intensity and concentration of a certain chemical element at a specific wavelength; where wavelengths λ1, λ2, ..., λ3 are constants. n To define multiple wavelengths distributed within the measurement interval;

[0007] At wavelengths λ1, λ2, ..., λ n In this process, characteristic wavelengths are selected based on the light intensity values ​​of chemical elements at various wavelengths. Each characteristic wavelength corresponds to a light intensity peak of a certain chemical element, and this wavelength is defined as the characteristic wavelength λ of that chemical element. xmax, define the set of all characteristic wavelength as peak wavelength set λ;

[0008] For the measured substance, flame photometric spectral analysis is performed to form an input light intensity matrix, and the detection step includes:

[0009] S1. Find the maximum light intensity value point in the input light intensity matrix A, and the maximum light intensity value of the maximum light intensity value point is A xmax , the corresponding wavelength value λ xmax ;

[0010] S2. Check whether the wavelength value λ xmax belongs to the characteristic wavelength value in the peak wavelength set λ of the standard spectral constant matrix K, if yes, go to step S4, otherwise go to step S3;

[0011] S3. Discard the maximum light intensity value point obtained in step S1 in the input light intensity matrix, and then re-perform step S1 after discarding;

[0012] S4. Determine the chemical element type X according to the characteristic wavelength value, and calculate the concentration value C x =A xmax / K xmax ; wherein K xmax is the spectral constant of the standard spectral constant matrix K corresponding to the characteristic wavelength value λ xmax ;

[0013] And according to C x , the current peak light intensity matrix A D is calculated;

[0014] A D =C x ×K x ; K x is a row vector representing x chemical elements in the standard spectral constant matrix;

[0015] S5. Subtract the current peak light intensity matrix from the input light intensity matrix in step S1 to obtain an intermediate matrix

[0016] Am=A- A1;

[0017] S6. Determine whether the intermediate matrix meets the continuous detection condition, if yes, continue to replace the input light intensity matrix with the intermediate matrix in step S1, continue to find the maximum light value and the corresponding wavelength value, and repeat steps S1-S5 until the continuous detection condition is not met, and the process is terminated.

[0018] After termination, the concentration value C x obtained during the implementation of steps S1-S5 each time is used to obtain the chemical element type and concentration contained in the measured substance.

[0019] Preferably, in the step S6, if the maximum value of the absolute value of any matrix element in the intermediate matrix is greater than a set threshold value, the intermediate matrix is returned to step S1, otherwise the process is terminated.

[0020] Preferably, the chemical element to be detected is sulfur, phosphorus, nitrogen, arsenic, chlorine.

[0021] Preferably, the flame photometric spectrum obtained in the data preparation and detection step is a spectrum collected by burning in a hydrogen flame.

[0022] The detection method for detecting the content of chemical elements using the flame photometric spectrum curve can complete the element analysis and detection of single compounds and mixtures, and reduce false positives and false negatives in the detection process. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a specific embodiment of the detection method of the present application;

[0024] Figure 2 is a spectrum curve of a mixture of sulfur and phosphorus elements, Figure 2 The abscissa is the wavelength, and the ordinate is the light intensity. EMBODIMENT

[0025] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0026] The non-chemical elements of the present application generally refer to substances containing sulfur, phosphorus, nitrogen, arsenic, chlorine and other elements that are harmful to the human body in actual application; the following describes the detection of chemical substances containing five typical elements of sulfur, phosphorus, nitrogen, arsenic and chlorine.

[0027] First, the flame photometric test standard spectrum constant matrix K = [K ij ] of chemical elements containing sulfur, phosphorus, nitrogen, arsenic and chlorine is obtained by experimental measurement. ij The subscript i represents different chemical elements, such as i = 1 for sulfur S, 2 for phosphorus P, and the subscript j represents different wavelengths λ1, λ2,... λ n n is the number of test points, and K ij is the spectral constant of a certain chemical element at a certain wavelength.

[0028] The set concentration is a concentration value within the linear range of concentration and light intensity. Since the concentration value does not affect the wavelength point corresponding to the light intensity peak, and the light intensity peak is in a nearly linear positive relationship with the concentration value, the most typical concentration of the light intensity curve of the substance can be selected during the experiment.

[0029] Wavelength λ1, λ2,... λ nTypically, multiple wavelength points are uniformly distributed within the wavelength range of a typical peak distribution. For example, in the wavelength range of 300-900 nanometers, elements such as sulfur, phosphorus, arsenic, and chlorine can all achieve wavelength peaks. Therefore, n wavelength points uniformly distributed within the 300-900 nanometer range can be selected as λ1, λ2, ..., λ. n .

[0030] At wavelengths λ1, λ2, ..., λ n Within this context, the wavelength at which various chemical elements achieve peak light intensity at a given concentration is defined as the set of peak wavelengths λ. A peak wavelength is defined as the wavelength with the highest light intensity among all wavelengths greater and less than that wavelength within a given wavelength range. Figure 2 As shown, B1, B2, and B3 can be considered as three peaks.

[0031] The peak wavelength set λ is generally defined as the set of wavelengths at which all chemical elements achieve their peak values ​​within a specific wavelength range. Within this selected wavelength range, such as... Figure 2 As shown, a single element may achieve a peak at multiple different wavelengths, and each wavelength in the set of peak wavelengths λ can achieve a peak intensity at at least one chemical element.

[0032] For example, sulfur reaches its light intensity peak at λ2, and phosphorus reaches its peak at λ3 and λ7. In this case, λ2, λ3 and λ7 are included in the peak wavelength set λ.

[0033] If a chemical element reaches a peak value at a certain wavelength, then that wavelength is defined as the characteristic wavelength value of that chemical element.

[0034] The spectrum of the measured substance is filtered and denoised to form the input light intensity matrix A=[A x A x The light intensity value of the substance being tested containing chemical element x within the measurement range.

[0035] The specific testing process is as follows:

[0036] S1. Find the point with the maximum light intensity value in the input light intensity matrix A. The maximum light intensity value of the point with the maximum light intensity value is A. xmax The corresponding wavelength value λ xmax ;

[0037] S2. Check the wavelength value λ xmax If the wavelength value belongs to the characteristic wavelength value in the peak wavelength set λ, proceed to step S4; otherwise, proceed to step S3.

[0038] S3. Discard the maximum light intensity value obtained in step S1 in the input light intensity matrix, and then repeat step S1;

[0039] S4. Determine the chemical element species x by the characteristic wavelength value, calculate the concentration value C x =A xmax / K xmax ; wherein K xmax is the standard spectral constant matrix K corresponding to the spectral constant when the characteristic wavelength value is λ xmax ; and according to C x , the current peak light intensity matrix A D

[0040] A D =C x ×K x

[0041] K x is a row vector in the standard spectral constant matrix containing the chemical element x poison K;

[0042] S5. Subtract the current peak light intensity matrix from the input light intensity matrix to obtain an intermediate matrix

[0043] Am=A- A1;

[0044] S6. Determine whether the intermediate matrix meets the continued detection condition, if yes, continue to replace the input light intensity matrix with the intermediate matrix in step S1, continue to find the maximum light intensity value and the corresponding wavelength value for the intermediate matrix, repeat steps S1 to S5 until the continued detection condition is not met, and terminate the process.

[0045] For example, the standard spectral constant matrix K is as follows, assuming n=9, the underlined K 11 , K 22 , K 33 , K 44 , K 55 , K 27 , K 36 , K 18 corresponding wavelengths are the characteristic wavelength values of sulfur, phosphorus, nitrogen, arsenic, and chlorine elements:

[0046] λ1, λ 12 , λ3, λ4, λ5, λ6, λ7, λ8, λ9.

[0047] [1S \ K 11 , K 12 , K 13 , K 14 , K 15 , K 16 , K 17 , K 18 , K 19

[0048] 2P \K 21 ,K 22 , K 23 , K 24 , K 25 , K 26 , K 27 , K 28 , K 29

[0049] 3N\K 31 , K 32 , K 33 , K 34 , K 35 , K 36 , K 37 , K 38 , K 39

[0050] 4AS\K 41 , K 42 , K 43 , K 44 , K 45 , K 46 , K 47 , K 48 , K 49

[0051] 5Cl\K 51 , K 52 , K 53 , K 54 , K 55 , K 56 , K 57 , K 58 , K 59 ]

[0052] Input light intensity matrix

[0053] A=[ A1, A2, A3, A4, A5, A6, A7, A8, A9]

[0054] For example, the value of A3 is the largest among all light intensities A1-A9, and the corresponding wavelength λ3 is the characteristic wavelength value of nitrogen N element in the standard spectrum constant matrix K, which indicates that the detected substance contains nitrogen;

[0055] If the value of A9 is the largest among all light intensities A1-A9, and the corresponding wavelength λ9 is not the characteristic wavelength value of any chemical element in the standard spectrum constant matrix K, then A9 is discarded, and the input light intensity matrix after discarding is

[0056] [A1, A2, A3, A5, A6, A7, A8, A9] The above judgment is performed again. Among A1, A2, A3, A5, A6, A7, A8, A9, it is found that A7 has the largest value, and the corresponding wavelength λ7 is the characteristic wavelength value of phosphorus P in the standard spectral constant matrix K. This indicates that the detected substance also contains phosphorus.

[0057] For example, in the input light intensity matrix A=[A1, A2, A3, A4, A5, A6, A7, A8, A9]

[0058] If the value of A4 is the largest among all light intensities A1-A9, and the corresponding wavelength λ4 is the characteristic wavelength value of arsenic (As) in the standard spectral constant matrix K, then the substance being tested contains arsenic.

[0059] Calculate the concentration value C x =A4 / K xmax K xmax The spectral constant K corresponding to the characteristic wavelength value λ4 in the standard spectral constant matrix K. 44 ,

[0060] Since the spectral constant corresponding to the characteristic wavelength value is the most accurate, the concentration value C can be calculated. x C is calculated using the spectral constant corresponding to the characteristic wavelength value. x =A4 / K 44 .

[0061] Calculate C x Then, calculate the current peak light intensity matrix A. D =C x ×K x

[0062] K x For K xmax That is, K in the standard spectral constant matrix K 44 The row vector

[0063] [K 41 K 42 K 43 , K 44 K 45 K 46 K 47 K 48 K 49 ];

[0064] A D =[ C x *K 41 C x *K 42 C x *K 43 Cx * K 44 、C x *K 45 、C x *K 46 、C x *K 47 、C x *K 48 、C x *K 49 ];

[0065] intermediate matrix Am = A - A D ;

[0066] Am = [A1 - C x *K 41 , A2 - C x *K 42 , A3 - C x *K 43 , A4 - C x * K 44 , A5 - C x *K 45 , A6 - C x *K 45 , A7 - C x *K 47 , A8 - C x *K 48 , A9 - C x *K 49 ]

[0067] One embodiment of the determination of whether the intermediate matrix Am meets the continue detection condition is to take the absolute value of all the matrix elements, and if any one of the absolute values is greater than a set threshold value, it indicates that the substance being tested may still contain other chemical elements, and the steps S1-S5 are repeated for analysis, i.e. it is possible to obtain other chemical elements with lower content. Until all the absolute values are less than or equal to the set threshold value, it indicates that the concentration value represented by the light intensity in the intermediate matrix has been reduced to the point where it is no longer meaningful to detect, and further analysis is not required. The setting of the set threshold value is set according to the detection accuracy, for example, it is considered that when the detection concentration of any one element reaches the minimum limit indicated by the instrument, the detection can be terminated, and the corresponding set threshold value is set.

[0068] After termination, the concentration values C x obtained during each S1 to S5 step are used to obtain the types and concentrations of chemical elements contained in the substance being tested.

[0069] The foregoing is merely preferred embodiments of the present application, and the preferred embodiments in each preferred embodiment can be arbitrarily combined and used if not obviously contradictory or with a certain preferred embodiment as a prerequisite. The embodiments and specific parameters in the embodiments are only for the purpose of clearly describing the inventor's verification process, and are not intended to limit the patent protection scope of the present application. The patent protection scope of the present application is still subject to its claims, and any equivalent structural changes made by using the content of the specification and drawings of the present application should also be included in the protection scope of the present application.

Claims

1. A method for detecting the content of chemical elements using flame photometric spectroscopy, characterized in that, This includes data preparation, detection steps, and the derived formulas for detecting the content of chemical elements. The data preparation includes: The standard spectral constant matrix K = [K] containing all the chemical elements to be tested was obtained through experimental measurement. ij ], K ij The subscript i represents different chemical elements, and the subscript j represents different wavelengths λ1, λ2, ... λ. n n is the number of test points, K ij Let be a constant relating the light intensity and concentration of a certain chemical element at a specific wavelength; where wavelengths λ1, λ2, ..., λ3 are constants. n To define multiple wavelengths distributed within the measurement interval; At wavelengths λ1, λ2, ..., λ n In this process, characteristic wavelengths are selected based on the light intensity values ​​of chemical elements at various wavelengths. Each characteristic wavelength corresponds to a light intensity peak of a certain chemical element, and this wavelength is defined as the characteristic wavelength λ of that chemical element. xmax The set of all characteristic wavelengths is defined as the peak wavelength set λ. The substance to be tested is subjected to flame photometric spectroscopy analysis to form an input light intensity matrix. The detection steps include: S1. Find the point with the maximum light intensity value in the input light intensity matrix A. The maximum light intensity value of the point with the maximum light intensity value is A. xmax The corresponding wavelength value λ xmax ; S2. Check the wavelength value λ xmax If a wavelength value belongs to the set of peak wavelengths λ in the standard spectral constant matrix K, proceed to step S4; otherwise, proceed to step S3. S3. Discard the maximum light intensity value obtained in step S1 in the input light intensity matrix, and then repeat step S1. S4. Determine the type of chemical element X based on the characteristic wavelength value, and calculate the concentration value C. x =A xmax / K xmax ;where K xmax The standard spectral constant matrix K is at a characteristic wavelength of λ. xmax The corresponding spectral constant; And according to C x Calculate the current peak light intensity matrix A D ; A D =C x ×K x ;K x Let x be the row vector representing the chemical element x in the standard spectral constant matrix; S5. Subtract the current peak light intensity matrix from the input light intensity matrix in step S1 to obtain the intermediate matrix. Am = A - A1; S6. Determine whether the intermediate matrix meets the conditions for continuing detection. If yes, return the intermediate matrix to step S1 to replace the input light intensity matrix and continue to find the maximum light intensity value and the corresponding wavelength value. Repeat steps S1-S5 until the conditions for continuing detection are no longer met, and terminate the process. After termination, the concentration value C obtained during each of steps S1-S5 is used as the basis for calculation. x This allows us to obtain the types and concentrations of chemical elements contained in the substance being tested.

2. The detection method for detecting chemical element content using flame photometric spectroscopy curves as described in claim 1, characterized in that, In step S6, if the detection condition is that the maximum absolute value of any matrix element in the intermediate matrix is ​​greater than a set threshold, then the intermediate matrix is ​​returned to step S1; otherwise, the process is terminated.

3. The detection method for detecting chemical element content using flame photometric spectroscopy curves as described in claim 1, characterized in that, The chemical elements to be tested are sulfur, phosphorus, nitrogen, arsenic, and chlorine.

4. The detection method for detecting chemical element content using flame photometric spectroscopy curves as described in claim 1, characterized in that, The flame photometric spectrum obtained in the data preparation and detection steps is the spectrum collected during combustion in a hydrogen flame.

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