JP2019158587A - Quantitative analysis method - Google Patents

Abstract

To provide a quantitative analysis method allowing for quantitative analysis of concentration of an element to be analyzed included in human hair or animal hair.SOLUTION: The quantitative analysis method of the present invention calculates the concentration of an element to be analyzed included in an analysis sample, using: a first XRF spectrum obtained by detecting a secondary X-ray including fluorescence X-ray generated in the analysis sample by irradiating the analysis sample with primary X-ray using a fluorescence X-ray analyzer; a second XRF spectrum obtained by irradiating the analysis sample with the primary X-ray with a sample of the fluorescence X-ray analyzer as a blank; and a calibration curve, the analysis sample is human hair or animal hair, the quantitative analysis method includes the steps of: calculating an intensity ratio by using formula: the intensity ratio=(first net X-ray intensity - second net X-ray intensity)/(first background intensity - second background intensity); and calculating concentration of the element to be analyzed included in the analysis sample from the intensity ratio using the calibration curve.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a quantitative analysis method for calculating the concentration of an analysis target element contained in hair or animal hair using a fluorescent X-ray analyzer.

The human body requires essential minerals such as calcium, potassium, magnesium, iron, zinc and copper in order to make organs and tissues work smoothly. Knowing the excess and deficiency of essential minerals in the body is important for health management. In particular, calcium is one of information transmission substances, and calcium deficiency may cause disease. However, the calcium concentration in the blood is kept constant by homeostasis, and the excess or deficiency of calcium in the body cannot be examined by measuring the calcium concentration in the blood.
On the other hand, hair takes in and holds minerals in the body. For this reason, the excess or deficiency of mineral can be investigated by examining the mineral concentration of hair.
There are known methods for examining the mineral concentration in hair using ICP emission / mass spectrometry, atomic absorption spectrometry, or the like. However, these methods require a large amount of hair. Moreover, it is necessary to dissolve hair in an acid solution, and much time and labor are required for analysis.
Moreover, the method of measuring the density | concentration of the mineral contained in hair using a fluorescent X ray analysis method is known (for example, refer patent document 1). When the fluorescent X-ray analysis method is used, there are advantages such that the necessary amount of hair necessary for the analysis can be suppressed, and the time-consuming pretreatment can be omitted.

WO2014 / 132383A1

In conventional hair analysis using X-ray fluorescence analysis, a peak derived from sulfur contained in hair is used as an internal standard. However, there are individual differences in the sulfur concentration of hair. Moreover, the peak intensity derived from sulfur is considerably larger than the peak intensity of calcium, zinc, iron and the like. For this reason, the peak derived from sulfur is not suitable for use as an internal standard.
The present invention has been made in view of such circumstances, and provides a quantitative analysis method capable of simply and quantitatively analyzing the concentration of an analysis target element contained in hair or animal hair.

The present invention provides a first XRF obtained by detecting secondary X-rays including fluorescent X-rays (XRF) generated in the analysis sample by irradiating the analysis sample with primary X-rays using an X-ray fluorescence analyzer. Quantitative analysis method for calculating concentration of element to be analyzed contained in analysis sample from spectrum, second XRF spectrum obtained by irradiating primary X-ray with sample of fluorescent X-ray analyzer as blank, and calibration curve The analysis sample is hair or animal hair, and a step of calculating an intensity ratio using the following equation (1) and an analysis included in the analysis sample from the intensity ratio using the calibration curve And a step of calculating a concentration of the target element.
Intensity ratio = (first net X-ray intensity−second net X-ray intensity) / (first background intensity−second background intensity) (1), where the first background intensity is the object of analysis The intensity added to the first XRF spectrum due to a cause other than the fluorescent X-ray derived from the element to be analyzed in the energy range of the peak of the fluorescent X-ray derived from the element, and the second background intensity is derived from the element to be analyzed in the energy range Intensity added to the second XRF spectrum due to causes other than fluorescent X-rays, and the first net X-ray intensity is a peak intensity obtained by subtracting the first background intensity from the measured X-ray intensity of the first XRF spectrum in the energy range. Yes, the second net X-ray intensity is calculated from the measured X-ray intensity of the second XRF spectrum in the energy range. It is the peak intensity obtained by subtracting the de strength.

In the quantitative analysis method of the present invention, the concentration of the element to be analyzed contained in the analysis sample is calculated from the first XRF spectrum of the analysis sample, the second XRF spectrum of the blank sample, and the calibration curve.
The quantitative analysis method of the present invention includes a step of calculating an intensity ratio using the equation (1). In the numerator equation (1), the second net X-ray intensity is subtracted from the first net X-ray intensity to calculate the third net X-ray intensity (first net X-ray intensity−second net X-ray intensity = first 3 net X-ray intensity). The first net X-ray intensity is the amount of fluorescent X-rays generated by the analysis target element contained in the analysis sample and the amount of fluorescent X-rays generated by the analysis target element contained in the constituent members of the fluorescent X-ray analyzer. The second net X-ray intensity is considered to represent the amount of fluorescent X-rays generated by the analysis target element included in the constituent members of the fluorescent X-ray analyzer. For this reason, it is considered that the third net X-ray intensity represents the amount of fluorescent X-rays generated by the analysis target element contained in the analysis sample. The third net X-ray intensity increases as the amount of analysis sample increases.
In the denominator equation of equation (1), the third background intensity is calculated by subtracting the second background intensity from the first background intensity (first background intensity−second background intensity = third background intensity). . The first background intensity is considered to represent the sum of the amount of scattered radiation due to the elements contained in the analysis sample and the amount of scattered radiation due to the elements contained in the constituent members of the fluorescent X-ray analyzer. Intensity is considered to represent the sum of the amount of scattered radiation due to elements contained in the constituent members of the fluorescent X-ray analyzer. For this reason, it is considered that the third background intensity represents the amount of scattered radiation due to the elements contained in the analysis sample. The third background intensity increases as the amount of analysis sample increases.
Further, in Expression (1), the third net X-ray intensity is divided by the third background intensity to calculate an intensity ratio. Since both the third net X-ray intensity and the third background intensity increase as the amount of the analysis sample increases, fluctuations in the amount of the analysis sample (for example, the thickness of the hair) can be corrected by this division. Therefore, the calculated intensity ratio is considered to be a value corresponding to the concentration of the analysis target element contained in the analysis sample.

The quantitative analysis method of the present invention includes a step of calculating the concentration of the element to be analyzed from the intensity ratio using a calibration curve. By this step, the concentration of the analysis target element contained in the analysis sample can be calculated.
The analysis sample is hair or animal hair. Therefore, by the quantitative analysis method of the present invention, the concentration of the element to be analyzed contained in hair or animal hair can be quantitatively analyzed easily.

It is a schematic sectional drawing of the fluorescent-X-ray-analysis apparatus used with the quantitative analysis method of this invention. It is explanatory drawing of the analysis of the XRF spectrum by the quantitative analysis method of this invention. It is a graph which shows the relationship between the diameter of the hair used as an analysis sample, and background intensity | strength. It is the XRF spectrum of an analysis sample, and the XRF spectrum of a blank sample. (A) is a calibration curve showing the relationship between the concentration of sulfur (S) in the hair and the intensity ratio, and (b) is a calibration curve showing the relationship between the concentration of calcium (Ca) in the hair and the intensity ratio. Yes, (c) is a calibration curve showing the relationship between the concentration of iron (Fe) in hair and the strength ratio, and (d) is a calibration curve showing the relationship between the concentration of zinc (Zn) in hair and the strength ratio. Is a line.

The quantitative analysis method of the present invention is obtained by detecting secondary X-rays including fluorescent X-rays generated in the analysis sample by irradiating the analysis sample with primary X-rays using a fluorescent X-ray analyzer. Quantitative analysis that calculates the concentration of the target element contained in the analytical sample from the 1XRF spectrum, the second XRF spectrum obtained by irradiating the primary X-ray with the sample of the X-ray fluorescence analyzer as a blank, and the calibration curve In the method, the analysis sample is hair or animal hair, and is included in the analysis sample from the step of calculating an intensity ratio using the following formula (1) and the intensity ratio using the calibration curve. Calculating the concentration of the element to be analyzed.
Intensity ratio = (first net X-ray intensity−second net X-ray intensity) / (first background intensity−second background intensity) (1), where the first background intensity is the object of analysis The intensity added to the first XRF spectrum due to a cause other than the fluorescent X-ray derived from the element to be analyzed in the energy range of the peak of the fluorescent X-ray derived from the element, and the second background intensity is derived from the element to be analyzed in the energy range Intensity added to the second XRF spectrum due to causes other than fluorescent X-rays, and the first net X-ray intensity is a peak intensity obtained by subtracting the first background intensity from the measured X-ray intensity of the first XRF spectrum in the energy range. Yes, the second net X-ray intensity is calculated from the measured X-ray intensity of the second XRF spectrum in the energy range. It is the peak intensity obtained by subtracting the de strength.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

FIG. 1 is a schematic cross-sectional view of a fluorescent X-ray analyzer 10 used in the quantitative analysis method of the present embodiment. The X-ray fluorescence analyzer 10 is an energy dispersive X-ray fluorescence analyzer.
The X-ray fluorescence analyzer 10 includes an X-ray tube 5 that generates X-rays, a sample holder 3 for setting an analysis sample 2 in an analysis field, and a detector 6 for detecting fluorescent X-rays. The detector 6 is a semiconductor detector.
The analysis sample 2 is hair or animal hair. The analysis target element is, for example, calcium, potassium, magnesium, sulfur, iron, zinc, or copper.

  The primary X-ray 8 generated by the X-ray tube 5 is irradiated to the analysis sample 2 set in the analysis field. The primary X-ray 8 irradiated to the analysis sample 2 ejects inner shell electrons of elements contained in the analysis sample 2 to the outer shell. When the outer shell electrons fall into the vacant inner shell, the surplus energy is emitted as fluorescent X-rays (specific X-rays). An XRF spectrum can be obtained by detecting the secondary X-ray 9 including the fluorescent X-ray with the detector 6. Since the fluorescent X-ray has an element-specific wavelength (energy), the element contained in the analysis sample 2 can be qualitatively analyzed from the energy of the XRF spectrum, and the element contained in the analysis sample 2 can be determined from the X-ray intensity of the energy. Quantitative analysis is possible.

Secondary X-rays 9 incident on the detector 6 include fluorescent X-rays generated by the elements contained in the analysis sample 2, scattered rays by the elements contained in the analysis sample 2 (X-rays from which the primary X-rays are scattered), Examples include fluorescent X-rays generated by elements contained in the constituent members (device members, sample holders, etc.) of the fluorescent X-ray analyzer 10, scattered rays caused by elements contained in the constituent members of the fluorescent X-ray analyzer 10. The XRF spectrum obtained from the output of the detector 6 represents the amount of these fluorescent X-rays and the amount of these scattered rays.
Since X-ray fluorescence has a wavelength (energy) specific to the element, it appears as an intensity peak in the energy range in the XRF spectrum. Scattered rays are mainly X-rays whose wavelengths are continuously distributed, and therefore appear as background intensity in the XRF spectrum.

FIG. 2 is a diagram schematically showing an XRF spectrum. The amount of fluorescent X-ray derived from the analysis target element contained in the secondary X-ray 9 appears as the net X-ray intensity of the peak of the analysis target element shown in FIG. 2, and the amount of scattered radiation contained in the secondary X-ray 9 is It appears as the background intensity shown in FIG.
The background intensity is the intensity added to the XRF spectrum due to causes other than the fluorescent X-rays derived from the analysis target element in the peak energy range of the fluorescent X-rays derived from the analysis target element. Causes other than fluorescent X-rays are mainly scattered rays. The background intensity is an integrated intensity in the energy range. When the detection intensity of the detector 6 is represented by a count number, the integrated intensity can be calculated by adding the count numbers in the background intensity range indicated by the diagonal lines in FIG. Further, when the detection intensity of the detector 6 is represented by an arbitrary intensity, the area of the background intensity range indicated by the oblique lines in FIG. 2 can be set as the integrated intensity.
Since the background intensity mainly represents the amount of scattered radiation, the more the material that scatters primary X-rays, the greater the background intensity. That is, the background intensity increases as the amount of the analysis sample 2 increases.

  The energy range of the peak of the fluorescent X-ray derived from the analysis target element is an energy range indicated by ROI in the fluorescent X-ray analysis. For example, when the analysis target element is sulfur (S), the energy range is 2.19 keV to 2.43 keV. For example, when the analysis target element is calcium (Ca), the energy range is 3.55 keV to 3.83 keV. For example, when the analysis target element is iron (Fe), the energy range is 6.22 keV to 6.57 keV. For example, when the analysis target element is zinc (Zn), the energy range is 8.43 keV to 8.83 keV.

The net X-ray intensity is a peak intensity obtained by subtracting the background intensity from the measured X-ray intensity of the XRF spectrum in the peak energy range of the fluorescent X-ray derived from the analysis target element. Net X-ray intensity is the integrated intensity in the energy range.
When the detection intensity of the detector 6 is represented by a count number, the integrated intensity can be calculated by adding the count numbers in the range of the net X-ray intensity indicated by the oblique lines in FIG. Further, when the detected intensity is represented by an arbitrary intensity, the area in the range of the net X-ray intensity indicated by the oblique lines in FIG. 2 can be set as the integrated intensity.
Since the net X-ray intensity is considered to represent the amount of fluorescent X-rays from the analysis target element, the net X-ray intensity increases as the number of analysis target elements generating fluorescent X-rays increases. That is, the net X-ray intensity increases as the amount of the analysis sample 2 increases. For example, when the analysis sample 2 is hair, even if the hair has the same length and the same composition, the net X-ray intensity obtained differs depending on the thickness of the hair.

In the quantitative analysis method of this embodiment, the analysis sample 2 is set in the analysis field of view of the fluorescent X-ray analyzer 10 to obtain a first XRF spectrum. For example, hair (analytical sample) is set in the analytical field of view of the fluorescent X-ray analyzer 10 as shown in FIG. 1, and the primary X-ray 8 generated by the X-ray tube 5 is irradiated to the analytical sample 2 to analyze the analytical sample. The first XRF spectrum can be obtained by detecting the secondary X-ray 9 from 2 with the detector 6.
The first XRF spectrum is generated by the amount of fluorescent X-rays generated by the elements contained in the analytical sample 2, the amount of scattered radiation by the elements contained in the analytical sample 2, and by the elements contained in the constituent members of the fluorescent X-ray analyzer 10. It is considered to represent the total amount of fluorescent X-rays and the amount of scattered radiation due to elements contained in the constituent members of the fluorescent X-ray analyzer 10.
The first net X-ray intensity of the peak of the analysis target element and the first background intensity in the energy range are calculated from the first XRF spectrum. When there are a plurality of analysis target elements, the calculation is performed for each analysis target element. As the peak of the element to be analyzed, a peak of Kα ray can be used.

In the quantitative analysis method of the present embodiment, the second XRF spectrum is obtained using the sample as a blank without setting the analysis sample 2 in the X-ray fluorescence analyzer 10. The measurement conditions for the second XRF spectrum are the same as the measurement conditions for the first XRF spectrum. For example, the primary X-ray 8 is generated by the X-ray tube 5 as a blank without setting the analysis sample 2 in the analysis visual field of the fluorescent X-ray analyzer 10 as shown in FIG. The second XRF spectrum can be obtained by detecting at.
The second XRF spectrum represents the sum of the amount of fluorescent X-rays generated by the elements contained in the constituent members of the fluorescent X-ray analyzer 10 and the amount of scattered radiation by the elements contained in the constituent members of the fluorescent X-ray analyzer 10. Conceivable.
The second net X-ray intensity of the peak of the analysis target element and the second background intensity in the energy range are calculated from the second XRF spectrum. When there are a plurality of analysis target elements, the calculation is performed for each analysis target element. As the peak of the element to be analyzed, a peak of Kα ray can be used.

The intensity ratio is calculated by applying the first and second net X-ray intensities and the first and second background intensities calculated for the analysis target element to Equation (1). When there are a plurality of analysis target elements, the intensity ratio is calculated for each analysis target element.
Intensity ratio = (first net X-ray intensity−second net X-ray intensity) / (first background intensity−second background intensity) (1)
In the numerator equation (1), the second net X-ray intensity is subtracted from the first net X-ray intensity to calculate the third net X-ray intensity (first net X-ray intensity−second net X-ray intensity = first 3 net X-ray intensity). The first net X-ray intensity includes the amount of fluorescent X-rays generated by the analysis target element included in the analysis sample 2 and the amount of fluorescent X-rays generated by the analysis target element included in the constituent members of the fluorescent X-ray analyzer 10. The second net X-ray intensity is considered to represent the amount of fluorescent X-rays generated by the analysis target element included in the constituent members of the fluorescent X-ray analyzer 10. For this reason, the third net X-ray intensity is considered to represent the amount of fluorescent X-rays generated from the analysis target element contained in the analysis sample 2. The third net X-ray intensity increases as the amount of the analysis sample 2 increases.
When the peak of the analysis target element does not appear in the second XRF spectrum of the blank sample, the second net X-ray intensity is set to zero.

  In the denominator equation of equation (1), the third background intensity is calculated by subtracting the second background intensity from the first background intensity (first background intensity−second background intensity = third background intensity). . The first background intensity is considered to represent the sum of the amount of scattered radiation due to the elements contained in the analytical sample 2 and the amount of scattered radiation due to the elements contained in the constituent members of the fluorescent X-ray analyzer 10. The background intensity is considered to represent the sum of the amount of scattered radiation due to elements contained in the constituent members of the fluorescent X-ray analyzer 10. For this reason, the third background intensity is considered to represent the amount of scattered radiation due to the elements contained in the analysis sample 2. The third background intensity increases as the amount of the analysis sample 2 increases.

  In Expression (1), the intensity ratio is calculated by dividing the third net X-ray intensity by the third background intensity. Since the third net X-ray intensity and the third background intensity both increase as the amount of the analysis sample 2 increases, the variation in the amount of the analysis sample 2 can be corrected by this division. Therefore, the calculated intensity ratio is considered to be a value corresponding to the concentration of the analysis target element contained in the analysis sample 2. For example, when the analysis sample 2 is hair, the thickness of the hair can be corrected by the equation (1).

From the calculated intensity ratio, the concentration of the element to be analyzed is calculated using a calibration curve. By this step, the concentration of the analysis target element contained in the analysis sample 2 can be calculated.
When there are a plurality of analysis target elements, the concentration can be calculated for each analysis target element. For example, when the analysis sample 2 is hair and the analysis target element is S, Ca, Fe, or Zn, the concentration of these elements in the hair can be calculated.

The calibration curve measures the first XRF spectrum of the analytical sample 2 (standard sample, etc.) whose concentration of the detection target element is known in advance, and uses the first XRF spectrum and the second XRF spectrum of the blank sample to calculate the intensity from equation (1). The ratio can be calculated and created from the element concentration known in advance and the calculated intensity ratio.
Further, the analytical sample after the first XRF spectrum is measured may be subjected to ICP emission analysis to measure the element concentration to create a calibration curve.
The calibration curve can be an expression showing the relationship between the intensity ratio and the concentration.

First XRF analysis experiment Using a tabletop fluorescent X-ray analyzer, XRF analysis was performed using hairs of different thicknesses as analysis samples. For the sample, seven hairs (65 μm to 95 μm in diameter) of the same person with different thicknesses were used.
In this experiment, one hair was pinned into an opening of a cylindrical sample holder (made of plastic), and the hair (analytical sample) was fixed to the sample holder with tape so that the linear hair entered the visual field for analysis. Then, XRF analysis was performed on hairs having different thicknesses to obtain XRF spectra. By stretching the hair in a straight line, the length of the hair entering the analysis field becomes the same, and the volume of the hair in the analysis field changes depending on the thickness of the hair. Note that no polypropylene film is used.
Rhodium (Rh) was used as the target of the X-ray tube, the tube voltage of the X-ray tube was 50 kV, and the tube current was 1.0 mA. Further, an ND filter was used and the collimator diameter was 9 mm. In addition, analysis was performed for 600 seconds in an air atmosphere.

The background intensity (integrated intensity) in the energy range of 10 keV to 11 keV was calculated from the XRF spectrum as the analysis result. The relationship between the thickness of the hair used for the analysis sample and the calculated background intensity is shown in FIG.
As can be seen from FIG. 3, it was found that the background intensity increased as the thickness of the hair increased. When primary X-rays enter the hair, the primary X-rays are scattered by the elements contained in the hair and scattered rays are emitted. Since the amount of elements contained in the hair increases as the thickness of the hair increases, it is considered that the scattered radiation increases. It is considered that the background intensity increased with the increase of the scattered radiation. Therefore, it was found that there is a correlation between the volume of the analysis sample and the background intensity.

XRF analysis was performed on analysis samples 1 to 6 in which the experimental mass of the second XRF analysis was changed. As an analysis sample, a hair standard sample (NIES CRM No. 13 hair) manufactured by National Institute for Environmental Studies was used. The concentration of sulfur (S) in the standard sample is 5000 ppm, the concentration of calcium (Ca) is 746 ppm, the concentration of iron (Fe) is 127 ppm, and the concentration of zinc (Zn) is 157 ppm. The standard sample is a powder sample (particle size of 100 μm or less). As shown in FIG. 1, a polypropylene film (thickness: 4 μm) is placed under a cylindrical sample holder, and 5.32 mg, XRF analysis was performed using 11.7 mg, 24.8 mg, 34.5 mg, 48.7 mg or 53.8 mg of the analytical sample. Further, XRF analysis was performed as a blank sample without placing the analysis sample on the film.
Rhodium (Rh) was used as the target of the X-ray tube, and the tube voltage of the X-ray tube was 50 kV. The tube current was optimized for each measurement sample in the range of 0.1 mA to 1.0 mA. Further, an ND filter was used and the collimator diameter was 9 mm. In addition, analysis was performed for 60 seconds in an air atmosphere.

  FIG. 4 shows an XRF spectrum that is an analysis result when the mass of the analysis sample is 53.8 mg and an XRF spectrum that is an analysis result of the blank sample. In the XRF spectrum of the analytical sample, peaks of sulfur, calcium, iron, copper, zinc, etc. were confirmed. Also, peaks of iron, copper, etc. were confirmed in the XRF spectrum of the blank sample. This peak is considered to be the detection of fluorescent X-rays generated from iron or copper contained in the constituent members of the fluorescent X-ray analyzer. The background intensity was generally larger in the XRF spectrum of the analytical sample than in the blank sample. This difference in background intensity is considered to be caused by the scattered light of the analysis sample.

Next, net X-ray intensity and background intensity of sulfur, calcium, iron, and zinc peaks were calculated from the obtained XRF spectrum. And the intensity ratio represented by following Formula was computed in the energy range of the peak of each element.
Intensity ratio = (Analytical sample net X-ray intensity−Blank sample net X-ray intensity) / (Analytical sample background intensity−Blank sample background intensity) (2)
Moreover, the average value, the standard deviation, and the relative standard deviation were calculated for the intensity ratio of each element of the analytical samples 1 to 6. The calculation results are shown in Table 1.

When the mass of the analysis sample was changed, the intensity ratio of the analysis samples 1 to 6 was found to be the same value, although there was some variation. Therefore, it was found that the amount of the analysis sample can be appropriately corrected by correcting the net X-ray intensity with the background intensity as in the above formula (2). That is, the thickness of the hair, the amount of the sample, and the like can be appropriately corrected by correcting the expression (2).
Next, a calibration curve was created using the average value of the intensity ratios of the analytical samples 1 to 6 for each element shown in Table 1 and the concentration of each element of the analytical sample (standard sample). The prepared calibration curve is shown in FIGS.

Quantitative analysis experiment
Quantitative analysis of mineral elements contained in hair was performed by XRF analysis. An analysis sample 7 obtained by cutting one forehead hair (about 2.5 cm) into four pieces was placed on a polypropylene film as shown in FIG. 1, and XRF analysis was repeated five times. In addition, XRF analysis is repeated five times by placing analytical samples 8 (total of 8) obtained by cutting 2 hairs (approximately 2.5 cm) of the same person into 4 pieces on a polypropylene film as shown in FIG. went. Further, XRF analysis was performed as a blank sample without placing the analysis sample on the film.
Rhodium (Rh) was used as the target of the X-ray tube, the tube voltage of the X-ray tube was 50 kV, and the tube current was 1.0 mA. Further, an ND filter was used and the collimator diameter was 9 mm. In addition, analysis was performed for 600 seconds in an air atmosphere.

  Next, the net X-ray intensity and background intensity of the sulfur, calcium, iron, and zinc peaks are calculated from the obtained XRF spectrum, and the intensity ratio is calculated by the above equation (2) in the energy range of each element peak. Calculated. And the density | concentration of each element contained in the analytical samples 7 and 8 was computed from the calculated intensity ratio and the calibration curve shown in FIG. In addition, an average value, a standard deviation, and a relative standard deviation were calculated for the concentrations of each element in the analytical samples 7 and 8. The calculation results for the analysis sample 7 are shown in Table 2, and the calculation results for the analysis sample 8 are shown in Table 3.

From the sulfur (S) concentrations shown in Tables 2 and 3, the accuracy of the quantitative method using the intensity ratio and the calibration curve could be confirmed. In addition, variation in the concentration of calcium (Ca) and zinc (Zn) could be reduced. Moreover, it was confirmed that the analytical sample 8 having a large amount of hair has higher quantitative accuracy than the analytical sample 7.
It was found that there was variation in the calculated iron (Fe) concentration. This is presumably because the iron concentration in the hair is low and the net X-ray intensity of the iron peak in the blank sample is high.

2: Analytical sample 3: Sample holder 4: Polypropylene film 5: X-ray tube 6: Detector 7: Camera 8: Primary X-ray 9: Secondary X-ray 10: X-ray fluorescence analyzer

Claims (2)

A first XRF spectrum obtained by detecting secondary X-rays including fluorescent X-rays generated in the analysis sample by irradiating the analysis sample with primary X-rays using an X-ray fluorescence analyzer, and the fluorescent X-rays A quantitative analysis method for calculating a concentration of an analysis target element contained in the analysis sample from a second XRF spectrum obtained by irradiating primary X-rays with a sample of an analyzer as a blank and a calibration curve,
The analysis sample is hair or animal hair,
Calculating an intensity ratio using equation (1) below;
Calculating a concentration of an element to be analyzed contained in the analysis sample from the intensity ratio using the calibration curve.
Intensity ratio = (first net X-ray intensity−second net X-ray intensity) / (first background intensity−second background intensity) (1)
Here, the first background intensity is an intensity added to the first XRF spectrum due to a cause other than the fluorescent X-ray derived from the analysis element in the energy range of the peak of the fluorescent X-ray derived from the analysis element,
The second background intensity is an intensity added to the second XRF spectrum due to causes other than the fluorescent X-ray derived from the analysis target element in the energy range,
The first net X-ray intensity is a peak intensity obtained by subtracting the first background intensity from the measured X-ray intensity of the first XRF spectrum in the energy range.
The second net X-ray intensity is a peak intensity obtained by subtracting the second background intensity from the measured X-ray intensity of the second XRF spectrum in the energy range.   The quantitative analysis method according to claim 1, wherein the element to be analyzed is calcium, potassium, magnesium, sulfur, iron, zinc, or copper.