JPH1164251A - Instrument and method for qualitative analysis of sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide objective high-accuracy qualitative analysis by eliminating the discrepancy between measured data and standard data. SOLUTION: Intensity and angle of diffraction of diffracted X-rays coming out of a sample when the sample is irradiated with X-rays are measured, and the measured data about the measured diffracted X-rays are calculated based on the measured intensity and angle of diffraction. Then, the standard data having the peak position corresponding to that of the measured data within an allowable tolerance are retrieved by comparing the measured data with the standard data about the peak positions of the already known diffracted X-rays for various kinds of materials. Then, the standard data having a discrepancy from the peak position of the measured data are extracted from among the retrieved standard data and corrected, so that the peak position of the extracted standard data may become coincident with that of the measured data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a qualitative analyzer for a sample using an X-ray diffraction method and a method therefor.

[0002]

2. Description of the Related Art Qualitative analysis of a sample using an X-ray diffraction method is performed by performing an X-ray diffraction measurement on an unknown substance (sample), obtaining a diffraction X-ray peak position (measurement data) of the sample, and obtaining a known value. Compared with the diffraction X-ray peak position (standard data) of the substance, if any of the peak positions of the measurement data coincide with the peak positions of the standard data, it is determined that the known substance is contained in the sample. This is an analysis method for determination.

FIG. 5 is a flowchart showing a conventional sample qualitative analysis means using the X-ray diffraction method, and FIG.
FIG. 6 is a diagram illustrating a display example of measurement data and standard data corresponding to the flow of the flowchart in FIG. 5. According to the conventional sample qualitative analysis means, first, a sample is filled in a sample plate and mounted on a sample stage of an X-ray diffractometer. Next, as shown in FIG. 5, the X-ray diffraction apparatus is driven to perform X-ray diffraction measurement on the sample (S101). In X-ray diffraction measurement, X
When a line is irradiated at an arbitrary angle θ, a diffracted X-ray emitted from the same sample at a diffraction angle of 2θ is detected. By this X-ray diffraction measurement, the relationship between the intensity (I) of the diffracted X-ray of the sample as shown in FIG. 6A and the diffraction angle (2θ) at which the diffracted X-ray is emitted is measured.

Next, a peak position of the diffracted X-ray is calculated from the measurement result obtained by the X-ray diffraction measurement (S102),
Measurement data relating to the diffraction X-ray peak position of the sample as shown in FIG.

The peak position of the diffracted X-ray has a specific pattern depending on the substance, and the peak position pattern for each known substance is standardized in advance and is known.
For example, there is “ICDD data” as a set of standard data of diffraction X-ray peak positions for known substances. On the other hand, when the sample to be measured is a mixture of a plurality of substances (generally, the sample is such a mixture), the peak position patterns of the substances contained in the samples are mixed in the measurement data. It will be.

Therefore, the peak position pattern of the measured data is compared with the peak position pattern of the known substance (S
103, see FIG. 6 (c)), if the peak position pattern of the measured data includes a pattern that matches the peak position pattern of the known substance, it is detected, and the known substance is included in the sample. It is determined that there is.

For this reason, the conventional qualitative analyzer uses various known methods to determine whether the peak position pattern of the measured data contains a peak position pattern that matches the peak position pattern of a known substance within a predetermined error range. The peak position pattern (standard data) of the known substance extracted and extracted automatically for each substance and the peak position pattern (measurement data) of the sample are displayed on a display device such as a CRT display (S104, FIG. 6 (d)). ), And the inspector visually inspected the displayed standard data and measurement data to make a final decision. Then, the standard data determined to be included in the measurement data is registered, and these data are printed on the same scale, thereby completing the qualitative analysis.

[0008]

The peak position pattern of a substance is such that when a constituent element of a crystal changes, such as a rock mineral or a solid solution, the peak position of a diffraction X-ray shifts. Also, in the X-ray diffraction measurement under heating,
The peak position of the substance contained in the sample may shift due to the thermal expansion of the sample. As described above, the peak position pattern in the measurement data often does not match the standard data due to various factors, and even if the same substance is used, the peak position pattern is generally shifted. .

Conventionally, the deviation of the peak position pattern between the measured data and the standard data (δ in FIG.
An error was allowed, and the display device displayed each data in a state where such a deviation was generated, and the inspector made a judgment in consideration of the error. The analysis result is registered and printed with the peak position pattern between the measurement data and the standard data being shifted.

[0010] However, if the inspector makes a judgment while the deviation δ remains between the measured data and the standard data, the judgment result of the inspector becomes subjective, and thus the analysis results vary, and the analysis accuracy is degraded. There was a possibility that it would be. The present invention has been made in view of such circumstances, and it is an object of the present invention to eliminate a gap between measured data and standard data and to realize objective and highly accurate qualitative analysis.

[0011]

According to the present invention, there is provided a qualitative analyzer for a sample using an X-ray diffraction method, which comprises the following constitution. Diffraction X-ray measuring means for measuring the intensity and diffraction angle of the diffracted X-rays emitted from the sample when the sample is irradiated with X-rays Based on the intensity and the diffraction angle of the diffracted X-rays measured by the diffracted X-ray measuring means, Arithmetic means for calculating measurement data relating to the diffraction X-ray peak position Storage means for storing standard data relating to the diffraction X-ray peak position for various substances Comparison between the measurement data and the standard data Comparison means for searching for standard data having a peak position corresponding to the peak position Among the searched standard data, standard data having a deviation from the peak position of the measured data is extracted, and the peak position of the standard data is measured. Correction means for making correction so that the peak position substantially matches

According to the present invention having such a configuration, the peak position of the standard data is corrected so as to substantially coincide with the peak position of the measured data. Therefore, a comparative analysis between the corrected standard data and the measured data is performed. Can be easily and objectively performed.

In the present invention having the above-described configuration, the correcting means may shift the peak position of the standard data to be corrected. As described above, by shifting the peak position of the standard data calculated in advance with reference to the peak position of the measurement data, the measurement data and the standard data can be substantially matched easily.

Further, the correction means may recalculate the peak position by changing the lattice spacing at a fixed ratio with respect to the material of the standard data to be corrected. in this way,
By changing the lattice position at a fixed ratio and recalculating the peak position for the substance of the standard data, the deviation of the diffraction angle between the qualitatively analyzed measurement data and the standard data such as ICDD can be reduced. Moreover, the distinction between measurement data that has not been qualitatively analyzed becomes clear. As a result, the standard data and the measured data can be compared and analyzed with higher accuracy.

Further, the correction means may recalculate the peak position by changing the lattice constant for the material of the standard data to be corrected. In this way, by recalculating the peak position by changing the lattice constant of the substance of the standard data, the deviation of the diffraction angle between the qualitatively analyzed measurement data and the standard data such as ICDD can be further reduced. In addition, the distinction between measurement data that has not been qualitatively analyzed becomes clearer. As a result, the standard data and the measured data can be compared and analyzed with higher accuracy.

The above-described qualitative analyzer of the present invention may be configured to include output means for outputting the measured data and the standard data corrected by the correction means, and the required standard stored in the storage means. A configuration including a data updating unit for updating the data to the standard data corrected by the correcting unit may be employed.

The method for qualitatively analyzing a sample according to the present invention
When the sample is irradiated with X-rays, the intensity and the diffraction angle of the diffracted X-rays emitted from the sample are measured, and based on the measured intensity and the diffraction angle of the diffracted X-rays, measurement data on the peak position of the diffracted X-rays is obtained. Calculate and compare the measured data with standard data on the peak position of diffracted X-rays that are known for various substances. Standard data having a peak position corresponding to the peak position of the measured data within an arbitrary allowable range And, among the retrieved standard data, extract standard data having a deviation from the peak position of the measured data, and correct the peak position of the standard data so as to substantially match the peak position of the measured data. It is characterized by: According to the method of the present invention as well, the peak position of the standard data is corrected so as to substantially coincide with the peak position of the measured data, so that the comparative analysis between the corrected standard data and the measured data can be easily and objectively performed. Becomes possible.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram schematically showing a sample qualitative analyzer according to an embodiment of the present invention, and FIG. 2 is a block diagram of a control unit constituting a part of the same device. As shown in FIG. 1, the sample qualitative analyzer according to this embodiment includes an X-ray diffraction measurement unit 1
The X-ray diffraction measurement unit 1 includes an X-ray generator 11, a goniometer 12, and an X-ray detector 13.

The structure of the X-ray diffraction measurement unit 1 is well known in the art. A sample S to be measured is mounted on a sample stage provided at the center of rotation of the goniometer 12, and X-ray diffraction X-rays are emitted from the ray generator 11 at an angle of θ, and the intensity (I) of diffracted X-rays emitted at an angle of 2θ is detected by an X-ray detector 13. The goniometer 12 is a kind of goniometer. The goniometer 12 adjusts an X-ray irradiation angle (θ) and detects a diffraction angle (2θ) at which diffracted X-rays are emitted. That is, the X-ray diffraction measurement unit 1 has a function as a diffraction X-ray measurement unit that measures the intensity and diffraction angle of the diffracted X-rays emitted from the sample S when the sample S is irradiated with the X-rays. .

As shown in FIG. 2, the control unit 2 includes a central processing unit (CPU) 21, a ROM / RAM 22, a storage unit 23, an X-ray detector interface (SC I / O) 2
4, a goniometer interface 25, a keyboard interface 26, a display unit interface 27, a printer interface 28, and a mode switching unit 29.

The ROM / RAM 22 is a memory for storing a control program and the like. The central processing unit 21 controls the X-ray diffraction measurement unit 1 according to the control program stored in the ROM / RAM 22 in advance. , Necessary arithmetic processing, etc., to perform the qualitative analysis of the sample automatically.

Various information and analysis results required for qualitative analysis of the sample are registered in the storage unit 23. As various kinds of information necessary for qualitative analysis of a sample, for example, there is standard data on a peak position of a diffracted X-ray for various known substances. That is, the storage unit 23 has a function as a storage unit for the standard data. This standard data includes
For example, the content of “ICDD data” as described above is registered.

In this embodiment, as the standard data, the vertical axis represents the diffraction X-ray intensity (I), the horizontal axis represents the diffraction angle (2θ) of the diffraction X-ray, and the peak position of the diffraction X-ray intensity I is represented by the diffraction angle ( 2θ) is displayed in the form of a diffraction pattern. In addition,
As will be described later, the measurement data also includes the diffraction X on the horizontal axis.
The diffraction angle (2θ) of the X-ray is taken, and the peak position of the diffracted X-ray intensity (I) is processed in the form of a diffraction pattern indicating the diffraction angle (2θ).

The X-ray detector interface 24 is connected to the X-ray detector 13 in the X-ray diffraction measurement unit 1 described above, and inputs the intensity (I) of the diffracted X-ray detected by the X-ray detector 13. . Goniometer interface 25
Is connected to the goniometer 12 in the X-ray diffraction measurement unit 1 described above, outputs a control command from the central processing unit 21 to the goniometer 12, and detects the detection angle (2θ) of the diffracted X-ray sent from the goniometer 12. )
Enter

The keyboard interface 26 is connected to a keyboard 31 as input means. The display unit interface 27 has a CRT
A display unit 32 such as a display is connected, and a printer 33 is connected to the printer interface 28. Here, the display unit 32 and the printer 33 function as output means for outputting the analysis result.

The central processing unit 21 described above uses the intensity (I) of the diffracted X-ray measured by the X-ray diffraction measurement unit 1.
Functions as calculation means for calculating measurement data relating to the diffraction X-ray peak position based on the diffraction angle (2θ), and compares the measurement data with the standard data to determine the peak position (2θ) of the measurement data within an arbitrary allowable range. ), Comparing means for searching for standard data having a peak position (2θ) corresponding to the standard data, and extracting standard data having a deviation from the peak position (2θ) of the measured data from the searched standard data. It has a function as a correcting means for correcting the peak position (2θ) of the data so as to substantially match the peak position (2θ) of the measurement data. These functions are
It is executed according to a control program stored in the OM / RAM 22.

In this embodiment, in order to cause the central processing unit 21 to execute processing as correction means, a correction control program including the following three correction modes is previously stored in the RO.
It is stored in the M / RAM 22. Each peak position of the standard data to be corrected is shifted by an arbitrary amount (shift mode). For the material of the standard data to be corrected, the peak position (2θ) is calculated again by changing the lattice spacing at a fixed ratio (lattice spacing calculation mode). For the material of the standard data to be corrected, the peak position (2θ) is calculated again by changing the lattice constant (lattice constant calculation mode).

Selection of these correction modes is performed by the mode switching section 29. That is, when a mode selection signal is input by operating the keyboard 31, the mode switching unit 29 determines this mode selection signal,
The correction control program in the correction mode selected from the correction control programs stored in the RAM 22 is started.

Here, when the shift mode is selected, the shift (2θ) of the peak position between the standard data to be compared and the measured data is calculated, and the diffraction pattern (vertical axis I, In the horizontal axis 2θ), the diffraction angle (2
θ) is shifted by the calculated shift amount.

When the lattice spacing calculation mode is selected, the peak position (2θ) is recalculated by appropriately changing the lattice spacing of the substance according to the standard data to be compared. The peak position (2θ) of the standard data is corrected to substantially match the peak position (2θ) of the measurement data. Note that the lattice spacing of the substance and the diffraction X-ray intensity (I)
The following equation holds between the peak position (2θ) and d = λ / 2 sin (2θ / θ) (d: lattice spacing, λ: wavelength of X-ray used for X-ray diffraction measurement)

Further, when the lattice constant calculation mode is selected, the lattice position of the substance relating to the standard data to be compared is appropriately changed, and the peak position (2θ) is recalculated. Is corrected so that it substantially matches the peak position (2θ) of the measurement data.

Next, an embodiment of a method for qualitative analysis of a sample using the above-described qualitative analyzer will be described. FIG. 3 is a flowchart showing a procedure of a qualitative analysis method of a sample according to the embodiment of the present invention, and FIG. 4 is a diagram showing a display example of measurement data and standard data corresponding to the flow of the flowchart of FIG. First, the sample S is filled in a sample plate and mounted on the sample stage of the goniometer 12 in the X-ray diffraction measurement unit 1 shown in FIG. Next, as shown in FIG. 3, the X-ray diffraction measurement unit 1 is driven to perform X-ray diffraction measurement on the sample S (S1). In the X-ray diffraction measurement, the sample S
When a line is irradiated at an arbitrary angle θ, a diffracted X-ray emitted from the sample S at a diffraction angle of 2θ is detected.

Here, the diffraction angle (2θ) is measured in an arbitrary angle range (for example, 3 ° ≦ 2θ ≦ 80 °) in an arbitrary angle unit (for example, 0.02 °). The detection data of the diffraction X-ray intensity (I) obtained by the X-ray diffraction measurement is sent from the X-ray detector 13 to the control unit 2. In addition, scan data relating to the diffraction angle (2θ) in the X-ray diffraction measurement is sent from the goniometer 12 to the control unit 2.

Thereafter, the central processing unit 21 determines the diffraction X-ray intensity (I) and the diffraction angle (2θ) of the sample S based on the input data of the diffraction X-ray intensity (I) and the diffraction angle (2θ).
And the diffraction X as shown in FIG.
Obtained as a line intensity distribution figure.

Next, the central processing unit 21 calculates the peak position of the diffracted X-ray from the above-described diffracted X-ray intensity distribution pattern (FIG. 4A), and obtains the measured data relating to the peak position of the diffracted X-ray of the sample S. In the form of a diffraction pattern indicating the peak position (2θ) of the diffracted X-ray as shown in FIG.
2).

Subsequently, the central processing unit 21 calls up standard data on various substances stored in the storage unit 23 in advance, and executes comparison with the measured data (S3, FIG. 4).
(C)). Normally, the sample S is composed of a plurality of substances, and the measurement data shows the peak positions (2θ) of the diffracted X-rays relating to those substances. The central processing unit 21 detects standard data having a coincidence among the peak positions (2θ).

However, as described above, when the constituent elements of the crystal change, such as rock minerals and solid solutions, the peak position pattern of the substance (2θ)
Shifts. In the X-ray diffraction measurement under heating, the peak position (2θ) of the substance contained in the sample S may be shifted due to the thermal expansion of the sample S. As described above, the peak position pattern in the measurement data often does not match the standard data due to various factors, and even if the same substance is used, the peak position pattern is generally shifted.

Therefore, when comparing the measured data with the standard data, an arbitrary allowable range (for example, 0.1 ° to 0.1 °) is used.
2 °) is set in advance, and standard data having substantially the same peak position within the allowable range is searched.

Next, a correction is performed to make the peak position of the standard data (hereinafter simply referred to as standard data) extracted by the search coincide with the peak position of the measured data (S4). Here, when the measurement data is to be corrected, all the peak positions are uniformly shifted by the correction, and as a result, the peak positions that match the standard data before the correction are shifted by the correction. Become. Therefore, there is an inconvenience that it is not possible to display all of the searched standard data and measured data in agreement.

Therefore, in the embodiment of the present invention, by making the standard data the object of correction, it is possible to make each standard data coincide with the measured data. That is, the central processing unit 21 corrects the peak position of the standard data according to the correction mode selected in advance, so that the peak position substantially matches the corresponding peak position of the measurement data.

As a result of the correction processing, a diffraction pattern in a form in which the measured data and the respective standard data coincide with each other is obtained. These diffraction patterns are output to the display unit 32 at the same scale in response to a command from the central processing unit 21 (S5, see FIG. 4D). The inspector can easily and objectively determine the substance contained in the sample S by visually inspecting the diffraction pattern displayed on the same scale as described above.

Further, among the standard data stored in the central processing unit 21, the data corrected as described above is updated to the corrected content by a command from the central processing unit 21. That is, the central processing unit 21 has a function as a data updating unit that updates the required standard data stored in the storage unit 23 to the corrected standard data.

Further, when a print command of the qualitative analysis result is issued by operating the keyboard 31, the central processing unit 21
Outputs to the printer 33 the information of the diffraction pattern in a form in which the measured data and the respective standard data coincide with each other, and the printed output of the diffraction pattern is executed. On the other hand, if the correction mode is not selected, the measurement data and the standard data that matches within the allowable range are displayed and printed in a form in which the deviation has occurred as before (S6).

The present invention is not limited to the above embodiment. For example, the peak positions of the measurement data and the standard data can be handled by converting the diffraction angle (2θ) into the lattice spacing (d). in this case,
After inputting the diffraction X-ray intensity (I) and the diffraction angle (2θ) of the sample from the X-ray diffraction measurement unit, the central processing unit converts the diffraction angle (2θ) into the lattice spacing (d). Is executed.

[0045]

As described above, according to the present invention, the peak position of the standard data is corrected so as to substantially coincide with the peak position of the measured data. Can be easily and objectively analyzed, and an objective and high-precision qualitative analysis can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a sample qualitative analyzer according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control unit constituting a part of the device.

FIG. 3 is a flowchart showing a procedure of a qualitative sample analysis method according to the embodiment of the present invention.

FIG. 4 is a diagram showing a display example of measurement data and standard data corresponding to the flow of the flowchart of FIG. 3;

FIG. 5 is a flowchart showing a conventional sample qualitative analysis means using an X-ray diffraction method.

FIG. 6 is a diagram showing a display example of measurement data and standard data corresponding to the flow of the flowchart of FIG. 5;

[Explanation of symbols]

 1: X-ray diffraction measurement unit 2: control unit 11: X-ray generator 12: goniometer 13: X-ray detector 21: central processing unit 22: ROM / RAM 23: storage unit 24: X-ray detector interface 25: goniometer Interface 26: Keyboard interface 27: Display interface 28: Printer interface 29: Mode switching unit

Claims (7)

[Claims] 1. A qualitative analyzer for a sample using an X-ray diffraction method, wherein a diffraction X-ray measurement for measuring an intensity and a diffraction angle of a diffraction X-ray emitted from the sample when the sample is irradiated with X-rays. Means, calculating means for calculating measurement data relating to the peak position of the diffracted X-ray based on the intensity and the diffraction angle of the diffracted X-ray measured by the diffracted X-ray measuring means, and the peak position of the diffracted X-ray for various substances Storage means for storing standard data relating to the measurement data; comparison means for comparing the measurement data with the standard data to search for standard data having a peak position corresponding to the peak position of the measurement data within an arbitrary allowable range; Standard data having a deviation from the peak position of the measured data is extracted from the standard data thus obtained, and the peak position of the standard data is substantially matched with the peak position of the measured data. Qualitative analyzer of samples comprising the positive correcting means. 2. The sample qualitative analyzer according to claim 1, wherein said correcting means shifts each peak position of the standard data to be corrected. 3. The qualitative analyzer for a sample according to claim 1, wherein the correction unit is configured to correct a standard data substance to be corrected.
A qualitative sample analyzer for recalculating peak positions by changing lattice spacing at a fixed ratio. 4. The apparatus for qualitative analysis of a sample according to claim 1, wherein the correction means relates to a substance of the standard data to be corrected.
A qualitative analyzer for a sample, wherein a peak position is calculated again by changing a lattice constant. 5. The sample qualitative analyzer according to claim 1, further comprising an output unit that outputs the measurement data and the standard data corrected by the correction unit. A qualitative analyzer for the sample. 6. The qualitative sample analysis apparatus according to claim 1, wherein the required standard data stored in the storage unit is updated to the standard data corrected by the correction unit. A qualitative analyzer for a sample, comprising: 7. When a sample is irradiated with X-rays, the intensity and the diffraction angle of the diffracted X-rays emitted from the sample are measured, and the peak of the diffracted X-ray is determined based on the measured intensity and the diffraction angle of the diffracted X-rays. In addition to calculating the measurement data on the position, the measurement data was compared with standard data on the peak position of the diffracted X-ray known for various substances, and the peak position of the measurement data was corresponded within an arbitrary allowable range. The standard data having the peak position is searched, and the standard data having a deviation from the peak position of the measured data is extracted from the searched standard data, and the peak position of the standard data is substantially equal to the peak position of the measured data. A method for qualitative analysis of a sample, wherein the method is performed so as to match.