Method for determining arsenic content

Abstract

Provided is a technique for the highly sensitive quantification of As in a target sample in which Pb may be admixed. Provided is a method for determining the arsenic content in a target sample in which lead may be admixed, wherein this method uses: the intensity of the Kα line for arsenic in the spectrum of a target sample measured by using energy-dispersive X-ray fluorescence analysis; a first calibration curve for arsenic; and a first correction coefficient for correcting the arsenic-related overlap with lead. The first calibration curve and first correction coefficient in this method are obtained by using a plurality of standard samples that include a first standard sample that does not contain arsenic.

Description

How to Determine Arsenic Content

[0001] The present disclosure relates to a method for determining the arsenic content, and more particularly to a method for determining the arsenic content in a target sample that may be contaminated with lead.

[0002] It has been known that in analysis using energy dispersive X-ray fluorescence spectrometry, the peak energy of the characteristic X-rays of arsenic (As) Kα rays and the peak energy of the characteristic X-rays of lead (Pb) Lα rays are close to each other. This has led to the problem that the peak of the Kα rays of As and the peak of the Lα rays of Pb overlap in the X-ray fluorescence spectrum, causing one peak to interfere with the other peak in the quantitative determination of As or Pb.

[0003] Regarding the quantification of Pb in a sample containing a mixture of As and Pb, Japanese Patent Laid-Open Publication No. 2007-003331 (Patent Document 1) discloses a technique for quantifying Pb by utilizing the intensity of Pb Lβ rays when a peak of As Kβ rays is detected in the spectrum of the sample.

[0004] Japanese Patent Application Laid-Open No. 2007-003331

[0005] In recent years, there has been a demand for highly sensitive quantification of As, particularly in pharmaceutical or food analysis using energy dispersive X-ray fluorescence spectrometry. In samples containing a mixture of As and Pb, as mentioned above, the Kα peak of As overlaps with the Lα peak of Pb. Therefore, it is conceivable to use the Kβ peak of As for the quantification of As.

[0006] However, the peak intensity of the Kβ ray of As is about one-fifth of the peak intensity of the Kα ray of As, making it difficult to quantify As with high sensitivity. Furthermore, the peak of the Kβ ray of As overlaps with the peak of the Lα ray of Hg. Therefore, if a sample contains Hg, it is difficult to quantify As even if the peak intensity of the Kβ ray is used.

[0007] The present disclosure has been made in view of the above circumstances, and its purpose is to provide a technique for quantifying As with high sensitivity in a target sample that may contain Pb.

[0008] A method according to an aspect of the present disclosure is a method for identifying the arsenic content in a target sample possibly containing lead, by using the arsenic Kα ray intensity in a spectrum of the target sample measured according to energy dispersive X-ray fluorescence spectrometry, a first calibration curve for arsenic, and a first correction coefficient for correcting overlap of arsenic with lead, wherein the first calibration curve and the first correction coefficient are determined using a plurality of standard samples including a first standard sample that does not contain arsenic.

[0009] According to one aspect of the present disclosure, a technique is provided for highly sensitive quantification of As in a target sample that may be contaminated with Pb.

[0010] 1 is a diagram showing an example of an As calibration curve created using six types of standard samples containing a mixture of Pb and As. It shows a spectrum measured according to energy dispersive X-ray fluorescence spectrometry of a certain sample. It is a diagram showing an example of a calibration curve defined by the term "bj·Ij+cj" in equation (1) created from multiple standard samples containing a mixture of Pb and As. It is a diagram showing an overall configuration of an analysis system including an energy dispersive X-ray fluorescence analyzer. It is a diagram showing the hardware configuration of an information processing device 20. It is a diagram showing an example of a screen displayed in creating a correction equation. It is a diagram showing another example of a screen displayed in creating a correction equation. It is a diagram showing an example of a screen displaying the created correction equation. It is a flowchart of processing performed in the information processing device 20 to quantify the As concentration in an unknown sample.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0012] [Summary of the Disclosure] The present disclosure mainly describes a method for identifying the As content in a target sample in which Pb and As may be present together.

[0013] Figure 1 shows an example of an As calibration curve created using six types of standard samples containing a mixture of Pb and As. In Figure 1, the horizontal axis represents the standard value (As concentration in the standard samples).

[0014] In Figure 1, the vertical axis represents the measured intensity ratio for As. This measured intensity ratio means, for example, the value obtained by dividing the NET intensity value in an energy region (e.g., 10.30 to 10.80 keV) including the peak of the As Kα line in the spectrum by the integrated value of the intensity in the optimal background region (e.g., 10.50 to 13.50 keV). The NET intensity is the area value of the portion surrounded by the peak spectrum and the background. The detected intensity in the background region is derived, for example, according to the Statistically Sensitive Non-Linear Iterative Peak Clipping (SNIP) algorithm. For the SNIP algorithm, see, for example, "Background elimination using the SNIP algorithm for Bragg reflections from a protein crystal measured by a TOF single-crystal neutron diffractometer" (URL: https: / / iopscience.iop.org / article / 10.1088 / 1742-6596 / 664 / 7 / 072049 / pdf#:~:text=The%20statistics%2Dsensitive%20non%2Dlinear,the%20background%20under%20a%20peak.).

[0015] In FIG. 1, line L11 represents the calibration curve. FIG. 1 shows points P10 to P60, each representing the measurement value of six standard samples used to create the calibration curve. In the example of FIG. 1, the accuracy (σ) of the calibration curve is 1.71 ppm. Some of points P10 to P60 deviate relatively significantly from the calibration curve. This is thought to be due to the fact that the Pb concentrations are not constant among the six standard samples. This factor will be examined in more detail with reference to FIG. 2.

[0016] Figure 2 shows the spectrum of a sample measured by energy dispersive X-ray fluorescence spectroscopy. The sample in Figure 2 contains As and Pb. As shown by waveform W11, the Kα peak of As and the L peak of Pb overlap in the spectrum in Figure 1.

[0017] Since the Pb concentration is not constant among the six types of standard samples, it is assumed that the intensity of the Pb L-line peak that overlaps with the As Kα-line peak is not constant. This is thought to be one of the reasons why some of points P10 to P60 in Figure 1 deviate relatively significantly from the calibration curve.

[0018] In the present disclosure, the As content in a target sample is determined using not only a calibration curve but also a correction coefficient corresponding to the overlap of the As Kα line and the Pb L line. The following formula (1) represents the correction formula used to determine the As content.

[0019] Wj = bj · Ij + cj - pk · Wk (1) In formula (1), Wj represents the concentration of As. bj, cj, and pk represent constants. Ij represents the above-mentioned measured intensity ratio. Wk represents the concentration of Pb. More specifically, W represents the concentration. b and c represent constants. j represents As. p represents a constant. k represents Pb.

[0020] In equation (1), the term "bj·Ij+cj" on the right side represents a linear function of the measured intensity ratio, such as a calibration curve. The term "pk·Wk" on the right side represents a term that corrects the influence of overlap with the Pb peak. In equation (1), the term "bj·Ij+cj" constitutes an example of a first calibration curve, and the term "pk·Wk" constitutes an example of a first correction coefficient.

[0021] 3 shows an example of a calibration curve defined by the term "bj·Ij+cj" in formula (1) created from multiple standard samples containing a mixture of Pb and As. In FIG. 3, line L21 represents the straight line of "Wj=bj·Ij+cj".

[0022] In Fig. 3, points P10 to P60 are shown, similarly to Fig. 1. Note that the multiple standard samples used to create the calibration curve in Fig. 3 are different from the six types of standard samples to which points P10 to P60 correspond.

[0023] According to equation (1), the concentration Wj of As is derived as the value obtained by subtracting the correction term "pk · Wk" from the term "bj · Ij + cj." This means that in FIG. 3, points P20, P30, P40, P50, and P60 are each represented as the value obtained by subtracting the correction term "pk · Wk" from points P21, P31, P41, P51, and P61 on line L21, respectively. In the example of FIG. 3, the accuracy (σ) of the calibration curve is 0.023 ppm. Points P20, P30, P40, P50, and P60 are identified as the corrected points of points P21, P31, P41, P51, and P61 on line L21, respectively.

[0024] As described above, according to the present disclosure, by using formula (1), the As content in a target sample containing a mixture of Pb and As can be more accurately determined.

[0025] 4 is a diagram showing the overall configuration of an analysis system including an energy dispersive X-ray fluorescence analyzer. The X-ray fluorescence analysis system 100 includes an X-ray fluorescence analyzer 10, an information processing device 20, a display 40, and an input unit 34.

[0026] The X-ray fluorescence analyzer 10 is an energy dispersive X-ray fluorescence analyzer that measures the concentration of elements contained in a sample S, and is composed of a sample chamber 1 and a measurement chamber 5. The spaces inside the sample chamber 1 and the measurement chamber 5 are airtightly enclosed by a housing 3, and the interior can be kept in a vacuum, helium atmosphere, or air atmosphere as necessary.

[0027] The sample chamber 1 is provided with a sample stage 2 at the bottom. An opening 4 is formed in the sample stage 2. A sample S is placed on the sample stage 2 so as to cover the opening 4. The sample S is placed on the sample stage 2 so that the measurement position is exposed from the opening 4.

[0028] The XY stage 14 is configured to be able to move the sample S along the in-plane direction of the sample stage 2. The driving mechanism 15 can drive the XY stage 14 in two in-plane axial directions that are perpendicular to each other. This makes it possible to automatically adjust the measurement position of the sample S.

[0029] The measurement chamber 5 is equipped with an X-ray tube 7 and a detector 8 on its wall surface 6. The X-ray tube 7 irradiates primary X-rays toward the sample S. The X-ray tube 7 has a filament that emits thermions and a target that converts the thermions into predetermined primary X-rays and emits them. The primary X-rays emitted by the X-ray tube 7 are irradiated onto the measurement position of the sample S through the opening 4. Secondary X-rays (fluorescent X-rays) emitted by the sample S are incident on the detector 8, and the energy and intensity of the fluorescent X-rays are measured.

[0030] A shutter 9, a primary X-ray filter 11, a collimator 13, and an imaging unit 16 are installed in the measurement chamber 5. The shutter 9, the primary X-ray filter 11, and the collimator 13 are configured to be slidable by a drive mechanism 12 in a direction perpendicular to the plane of the paper in FIG.

[0031] The shutter 9 is made of an X-ray absorbing material such as lead, and can be inserted into the optical path of the primary X-rays to block the primary X-rays when necessary.

[0032] The primary X-ray filter 11 is made of a metal foil selected according to the purpose, and attenuates background components of the primary X-rays emitted from the X-ray tube 7 to improve the S / N ratio of required characteristic X-rays. In an actual device, a plurality of primary X-ray filters 11 made of different types of metal are used, and the primary X-ray filter 11 selected according to the purpose is inserted into the optical path of the primary X-rays by a drive mechanism 12.

[0033] The collimator 13 is an aperture with a circular opening in the center, and determines the size of the primary X-ray beam that irradiates the sample S. The collimator 13 is made of an X-ray absorbing material such as lead or brass. In an actual device, multiple collimators 13 with different opening diameters are arranged side by side in a direction perpendicular to the plane of the paper in FIG. 1 , and the collimator 13 selected according to the purpose is inserted into the primary X-ray beam line by the driving mechanism 12.

[0034] The imaging unit 16 is installed at the bottom of the measurement chamber 5. The imaging unit 16 is configured to capture an image of the measurement position of the sample S through an opening 4 formed in the sample stage 2. The imaging unit 16 includes an imaging element partitioned into a plurality of pixels, such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device). Image data from the imaging unit 16 is transmitted to an information processing device 20.

[0035] 5 is a diagram showing the hardware configuration of the information processing device 20. The information processing device 20 is mainly composed of a CPU (Central Processing Unit) 22, which is an arithmetic processing unit. The information processing device 20 may be, for example, a personal computer.

[0036] The information processing device 20 further includes a storage unit that non-temporarily stores programs and data. The information processing device 20 operates in accordance with the programs executed by the CPU 22. The storage unit includes a read-only memory (ROM) 24, a random access memory (RAM) 26, and a hard disk drive (HDD) 30. Note that specific examples of the storage unit are not limited to these.

[0037] The information processing device 20 further has an I / O (Input / Output) interface 28 and a communication interface 32. The communication interface 32 is an interface that allows the information processing device 20 to communicate with external devices including the X-ray fluorescence analyzer 10. The I / O interface 28 is an interface for input to or output from the information processing device 20. As shown in FIG. 2 , the I / O interface 28 is connected to an input unit 34 and a display 40. The input unit 34 is, for example, a keyboard and / or a mouse, and accepts input, including instructions for the information processing device 20, from the operator.

[0038] Returning to FIG. 4, the information processing device 20 is connected with the input unit 34 and the display 40 as well as the X-ray tube 7, the detector 8, and the imaging unit 16.

[0039] The information processing device 20 controls the X-ray fluorescence analyzer 10 based on the measurement conditions and the like input by the input unit 34. Specifically, the information processing device 20 controls the tube voltage, tube current, irradiation time, and the like of the X-ray tube 7, and also drives each of the shutter 9, primary X-ray filter 11, and collimator 13.

[0040] During measurement, the information processing device 20 acquires the spectrum of the secondary X-rays detected by the detector 8. The information processing device 20 performs quantitative analysis of each element based on the spectrum of the secondary X-rays detected by the detector 8.

[0041] The information processing device 20 further controls the imaging by the imaging unit 16, and before measurement, automatically detects a measurement position of the sample S based on image data acquired by the imaging unit 16. The information processing device 20 further selects a collimator 13 having an optimal opening diameter for the detected measurement position from among a plurality of collimators 13. The display 40 can display the image of the sample S imaged by the imaging unit 16, as well as the format of a report created by the information processing device 20.

[0042] [Creating the Correction Formula] The correction formula shown above as formula (1) is reproduced below.

[0043] Wj = bj · Ij + cj - pk · Wk (1) Three constants (bj, cj, pk) are required to create equation (1). To derive these three constants, multiple standard samples are prepared.

[0044] (Standard Samples A to F) Six types of standard samples A to F will be described below as examples of a plurality of standard samples.

[0045] Standard sample A is ultrapure water. Standard sample B is a sample prepared by diluting a reagent containing a mixture of As and Pb by a factor of 10. The As concentration is 1.5 ppm and the Pb concentration is 0.5 ppm.

[0046] Standard sample C was prepared by diluting a reagent containing a mixture of As and Pb by a factor of 5. The As concentration was 3.0 ppm and the Pb concentration was 1.0 ppm.

[0047] Standard sample D was prepared by diluting a reagent containing a mixture of As and Pb by a factor of 2. The As concentration was 7.5 ppm and the Pb concentration was 2.5 ppm.

[0048] Standard sample E is a stock solution of a reagent containing a mixture of As and Pb. The As concentration is 14.634 ppm and the Pb concentration is 4.878 ppm.

[0049] Standard sample F is a solution containing Pb but not As. The Pb concentration is 10.0 ppm.

[0050] (Determining Constants) A spectrum is measured for each of the six types of standard samples using the X-ray fluorescence analyzer 10. Then, Ij (measured intensity ratio of As) is determined from each spectrum. Note that Ij for standard samples A to C corresponds to points P10 to P30, respectively, in FIG. 3. Ij for standard samples D and E corresponds to points P50 and P60, respectively, in FIG. 3. Ij for standard sample F corresponds to point P40 in FIG. 3.

[0051] Then, for each of the six standard samples, Wj (As concentration), Wk (Pb concentration), and Ij are applied to equation (1), resulting in six equations with three unknown constants bj, cj, and pk.

[0052] Then, from these six equations, the constants bj, cj, and pk are identified by multiple regression analysis using the least squares method. The identified constants bj, cj, and pk are used to create a correction equation for As shown as equation (1).

[0053] Similarly, a correction formula for Pb is created. The correction formula for Pb is expressed by the following formula (2).

[0054] Wk=bk·Ik+ck−pj·Wj (2) In formula (2), Ik represents the measured intensity ratio for Pb. This measured intensity ratio means, for example, the value obtained by dividing the NET intensity (peak area) value in an energy region including the Pb Lα line peak in the spectrum (e.g., 10.32 to 10.82 keV) by the integrated value of the intensity in the background region of the spectrum (e.g., a part of the range from 10.50 to 15.00 keV).

[0055] In equation (2), the term "bk·Ik+ck" constitutes an example of a second calibration curve, and the term "pj·Wj" constitutes an example of a second correction coefficient.

[0056] The spectra of the eight standard samples can also be used to create a correction equation for Pb. From each spectrum, Ik (measured intensity ratio of Pb) is identified. Then, for each of the six standard samples, Wk (Pb concentration), Wj (As concentration), and Ik are applied to equation (2). This results in six equations with three unknown constants bk, ck, and pj.

[0057] Then, from these six equations, the constants bk, ck, and pj are identified by multiple regression analysis using the least squares method. The identified constants bk, ck, and pj are used to create a correction equation for Pb shown as equation (2).

[0058] The correction formula may be created by the information processing device 20. Fig. 6 is a diagram showing an example of a screen displayed when creating the correction formula. Fig. 7 is a diagram showing another example of a screen displayed when creating the correction formula.

[0059] The screen 410 in Fig. 6 includes input fields for setting various conditions related to the creation of a correction formula. For example, the input field 411 sets a method for determining the constants b, c, and p. In the example of Fig. 6, multiple regression analysis is set. The screen 420 in Fig. 7 includes an area 421 for inputting the As concentration in each standard sample and an area 422 for inputting the Pb concentration in each standard sample. After acquiring the As and Pb concentrations in each standard sample and the spectrum of each standard sample, the information processing device 20 identifies the measurement intensity ratio from the spectrum and creates a correction formula.

[0060] 8 is a diagram showing an example of a screen displaying the created correction formula. Screen 430 in FIG. 8 includes a field 431 displaying the calibration curve (W=b·I+c−p·W) specified by the correction formula. Six points P80 to P85 corresponding to the measured intensity ratios of the six types of samples are shown on the calibration curve.

[0061] 8, the As concentrations at points P81 to P85 are corrected in accordance with the correction formula that has been created, and the corrected As concentrations are shown as points P91 to P95.

[0062] 9 is a flowchart of a process performed by the information processing device 20 to quantify the As concentration in an unknown sample. In one implementation example, this process is performed by the CPU 22 executing a given program. Before the process of FIG. 9 is performed, the above equations (1) and (2) are stored in the HDD 30, and the spectrum of the unknown sample is measured.

[0063] 9, in step S10, information processing device 20 acquires Ij (measured intensity ratio of As) and Ik (measured intensity ratio of Pb) from the spectrum of the unknown sample.

[0064] In step S20, the information processing device 20 calculates a provisional Wj according to the following equation (1A) which includes some of the constants in equation (1).

[0065] Wj=bj·Ij+cj (1A) In step S30, the information processing device 20 calculates a provisional Wk according to the following equation (2A) which includes some of the constants in equation (2).

[0066] Wk=bk·Ik+ck (2A) In step S40, the information processing device 20 calculates a provisional Wj according to equation (1). Here, the latest Wk (Wk calculated in the immediately preceding step S30 or step S50) is used.

[0067] In step S50, the information processing device 20 calculates a provisional Wk according to equation (2). Here, the latest Wj (Wj calculated in the immediately preceding step S20 or step S40) is used.

[0068] In step S60, the information processing device 20 determines whether the difference between the latest Wj and the immediately previous Wj is less than a predetermined threshold d. If the information processing device 20 determines that the difference is equal to or greater than the threshold d (NO in step S60), the information processing device 20 returns control to step S40. As a result, the control of steps S40 to S60 is repeated until the difference becomes less than the threshold d. If the information processing device 20 determines that the difference is less than the threshold d (YES in step S60), the information processing device 20 ends the process of FIG. 9. In the process of FIG. 9, the latest Wj is identified as the concentration of As in the unknown sample. Also, in the process of FIG. 9, the latest Wk is identified as the concentration of Pb in the unknown sample.

[0069] In the present embodiment described above, correction formula (1) is used to identify the concentration (content) of As in an unknown sample. A sample containing Pb but not As is used as one of a plurality of standard samples for creating correction formula (1). In this sense, standard sample H constitutes an example of a first standard sample.

[0070] Correction formula (1) includes three constants (bj, cj, pk). In order for correction formula (1) to derive an accurate As concentration, at least three types of standard samples with different As to Pb concentration ratios are required. However, standard samples are generally prepared from a single reagent with a specific As to Pb concentration ratio. When standard samples are prepared using such a reagent, the As to Pb concentration ratio remains constant among the multiple standard samples, even if multiple standard samples with different dilution ratios are prepared.

[0071] If only standard samples with the same As and Pb concentration ratios are available and an operator lacks knowledge of the method described in this embodiment, the operator will correct the As concentration by inputting a fixed value as the correction coefficient (the value corresponding to the “pk·Wk” term in Equation (1)). However, there are differences between analytical instruments. Therefore, the correction coefficients to be used among multiple analytical instruments may be similar, but will not necessarily be the same. When analyzing trace amounts, the correction coefficient due to the differences between instruments becomes an analytical error and is added to the quantitative value. For example, when analyzing As −2.0 ppm, if the correction method of this method is used, the quantitative value of As will be 2.01 ppm, but if a fixed value is used, the quantitative value of As may be 2.25 ppm. Therefore, without knowledge of this embodiment, precise quantification is impossible.

[0072] Preparing multiple standard samples with different As / Pb concentration ratios places a heavy burden on the operator. In particular, with the X-ray fluorescence analyzer 10, it is common to perform tasks such as creating correction equation (1) approximately once every two weeks to check the stability of the analyzer. It is therefore desirable to avoid placing a heavy burden on the operator at this frequency as much as possible.

[0073] In contrast, in this embodiment, a sample containing only Pb but no As is used as one of the multiple standard samples. By using a standard sample containing only Pb but no As, a standard sample prepared from the above-mentioned reagent, and a standard sample containing neither As nor Pb, highly accurate correction coefficients and correction formulas can be provided while minimizing the burden on the operator.

[0074] Furthermore, by using multiple standard samples prepared from the above reagents at different dilutions, the number of standard samples used to create the correction formula can be increased without excessively increasing the burden on the operator.

[0075] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0076] (Item 1) A method according to one aspect is a method for identifying the arsenic content in a target sample that may contain lead, by using the arsenic Kα ray intensity in a spectrum of the target sample measured according to energy dispersive X-ray fluorescence spectrometry, a first calibration curve for arsenic, and a first correction coefficient for correcting overlap of arsenic with lead, wherein the first calibration curve and the first correction coefficient may be determined using a plurality of standard samples including a first standard sample that does not contain arsenic.

[0077] The analytical method described in paragraph 1 provides a technique for quantifying As with high sensitivity in a target sample that may contain Pb.

[0078] (Item 2) In the method according to item 1, the plurality of standard samples may further include one or more standard samples containing arsenic and lead.

[0079] According to the method described in the second paragraph, the accuracy of the first calibration curve and the first correction coefficient can be improved without imposing an excessive burden on the operator, thereby improving the accuracy of the identified arsenic content.

[0080] (Item 3) In the method according to item 1, the plurality of standard samples may further include two or more standard samples containing arsenic and lead in equal proportions.

[0081] According to the method described in the third paragraph, the accuracy of the first calibration curve and the first correction coefficient can be improved without imposing an excessive burden on the operator, thereby improving the accuracy of the identified arsenic content.

[0082] (Item 4) In the method according to any one of Items 1 to 3, the plurality of standard samples may further include one or more standard samples that are free of both arsenic and lead.

[0083] According to the method described in the fourth paragraph, the accuracy of the first calibration curve and the first correction coefficient can be improved without imposing an excessive burden on the operator, thereby improving the accuracy of the identified arsenic content.

[0084] (Item 5) In the method according to any one of items 1 to 4, the content of lead in the target sample may be further used to identify the content of arsenic.

[0085] According to the method described in paragraph 5, in determining the arsenic content, the influence of overlapping peaks of arsenic and lead in the spectrum measured by energy dispersive X-ray fluorescence spectrometry can be reliably eliminated.

[0086] (Item 6) The method according to item 5 may further include determining the lead content in the target sample using the intensity of the Lα line of lead in the spectrum, a second calibration curve for lead, and a second correction coefficient for correcting overlap of lead with arsenic.

[0087] According to the method described in item 6, in determining the arsenic content, the influence of overlapping peaks of arsenic and lead in the spectrum measured by energy dispersive X-ray fluorescence spectrometry can be more reliably eliminated.

[0088] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above-described embodiments, and is intended to include all modifications within the meaning and scope of the claims. Furthermore, it is intended that each technique in the embodiments can be implemented alone or, if necessary, in combination with other techniques in the embodiments to the extent possible.

[0089] 10 X-ray fluorescence analysis device, 20 information processing device, 100 X-ray fluorescence analysis system, 410, 420, 430 screen, 411 input field, 421, 422 area, 431 field.

Claims

1. A method for identifying the arsenic content in a target sample possibly containing lead, by utilizing the arsenic Kα ray intensity in the spectrum of the target sample measured according to energy dispersive X-ray fluorescence spectrometry, a first calibration curve for arsenic, and a first correction coefficient for correcting overlap of arsenic with lead, wherein the first calibration curve and the first correction coefficient are determined using a plurality of standard samples including a first standard sample that does not contain arsenic.

2. The method of claim 1, wherein the plurality of standard samples further includes one or more standard samples containing arsenic and lead.

3. The method of claim 1, wherein the plurality of standard samples further comprises two or more standard samples containing arsenic and lead in equal proportions.

4. The method of claim 1, wherein the plurality of standard samples further includes one or more standard samples that are both free of arsenic and free of lead.

5. The method of claim 1, further comprising determining the arsenic content based on the lead content in the target sample.

6. The method of claim 5, further comprising determining the lead content in the target sample using the intensity of the lead Lα line in the spectrum, a second calibration curve for lead, and a second correction factor for correcting for overlap with arsenic for lead.

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