Elemental analysis apparatus

Abstract

To provide a technology with which, in elementary analysis using a calibration curve associated with internal standard elements, it is possible to easily discover that the quantitative value of the element being analyzed is not an appropriate value.SOLUTION: Provided is an elementary analyzing device 1 comprising: an internal standard candidate element setting unit 42 that sets internal standard candidate element information in which the element to be analyzed is associated with a plurality of internal standard candidate elements; a standard sample measurement unit 43 that measures a standard sample that includes the element to be analyzed and the plurality of internal standard candidate elements by a known amount; a calibration curve creation unit 44 that creates, for each element to be analyzed, a calibration curve that corresponds to each internal standard candidate element, on the basis of the internal standard candidate element information and the measured result of the standard sample; an analysis target sample measurement unit 45 that measures the sample to be analyzed in which internal standard candidate elements are added by a prescribed amount for each; a quantitative value calculation unit 46 that calculates a quantitative value using the measured intensity of each element to be analyzed that was obtained by measuring the sample to be analyzed, the measured intensity of the plurality of internal standard candidate elements, and the calibration curve; and a quantitative value display unit 47 that displays the quantitative value of each element to be analyzed that was calculated for each internal standard candidate element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an elemental analyzer for quantifying elements contained in a sample. [Background technology]

[0002] Inductively coupled plasma mass spectrometers are used to quantify elements contained in various liquid samples, such as environmental water collected from rivers, lakes, and other sources, as well as drinking water. An inductively coupled plasma mass spectrometer is equipped with an inductively coupled plasma ion source and a mass analyzer. The inductively coupled plasma ion source generates inductively coupled plasma from argon gas, and atomized liquid samples are introduced into the plasma to generate atomic ions from the liquid samples. The atomic ions generated by the inductively coupled plasma ion source are introduced into the mass analyzer, where they are separated according to their mass-to-charge ratio and detected by an ion detector.

[0003] In inductively coupled plasma mass spectrometry, when analyzing a liquid sample containing an element with a larger mass than the target element, the Coulomb repulsion acting between the two ions in the mass analyzer tends to cause the target element ions to deviate from their intended flight path, resulting in a decrease in their measured intensity. Therefore, even if the content (concentration) of the target element is the same in two liquid samples, the measured intensity of the target element will differ between a sample containing an element with a larger mass than the target element and a sample not containing an element with a larger mass than the target element. To accurately quantify the target element in inductively coupled plasma mass spectrometry, it is necessary to eliminate the influence of these other ions. For this purpose, a technique known as the internal standard method is used (see, for example, Patent Document 1).

[0004] The internal standard method is a method for quantifying an analyte element based on the measured intensity of the analyte element and the measured intensity of an internal standard element that is previously assigned to the analyte element. In the internal standard method, a calibration curve is created by performing measurements using a standard sample prior to measuring the analyte sample. When creating a calibration curve, multiple standard samples containing specified amounts of the internal standard element and different known amounts of the analyte element are prepared, and the measured intensity of the internal standard element and the measured intensity of the analyte element are measured for each standard sample. Inductively coupled plasma mass spectrometry typically quantifies multiple types of analyte elements in a single measurement, so a calibration curve is created by assigning an internal standard element to each of the multiple analyte elements.

[0005] The internal standard element is selected so that it is not contained in the sample to be analyzed and has a magnitude similar to that of the target element when affected by other ions in the mass spectrometer. As described above, the magnitude of the influence from other ions depends on the mass relationship between the target element and the other ions. Therefore, an element with a mass close to that of the target element is generally selected as the internal standard element. When measuring the target element, a known amount of the internal standard element is added to the sample, and the intensities of the internal standard element and the target element are measured. The target element contained in the target sample is quantified based on the ratio of the two measured intensities obtained in this way, the amount of internal standard element added, and the calibration curve. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-324476 Summary of the Invention [Problem to be solved by the invention]

[0007] In the internal standard method, the measured intensity of the internal standard element can sometimes be abnormal, making it impossible to accurately quantify the target element, due to reasons such as the presence of a matrix or impurities in the sample being analyzed that have an unexpected effect on the element selected as the internal standard. However, if an inexperienced person is performing the analysis, they may not notice such an abnormality and may end up using an incorrect quantitative value as the analysis result.

[0008] The problem to be solved by the present invention is to provide a technique that can easily detect when the quantitative value of an analyte element is not appropriate in elemental analysis in which an analyte element contained in an analyte sample is quantified using a calibration curve created by associating the analyte element with an internal standard element. [Means for solving the problem]

[0009] In order to solve the above problems, the elemental analysis method according to the present invention comprises: setting internal standard candidate element information in which one or more analysis target elements are associated with a plurality of internal standard candidate elements, measuring a plurality of standard samples each containing one or more target elements to be analyzed in known amounts and each containing a plurality of candidate internal standard elements associated with the one or more target elements to be analyzed in known amounts, the standard samples having mutually different contents of the target elements to be analyzed; based on the information on the internal standard candidate elements, for each of the one to more target elements, creating a calibration curve corresponding to each of the multiple target elements using the measurement intensities of the multiple target elements and the measurement intensities of the target elements obtained by measuring the multiple standard samples; measuring an analysis sample containing unknown amounts of the one or more analysis target elements to which predetermined amounts of the plurality of internal standard candidate elements have been added; calculating a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample and the measurement intensities of each of the multiple candidate internal standard elements, and the calibration curve; displaying the quantitative values ​​calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; For each of the one or more target elements, a final quantitative value is determined based on the quantitative value calculated for each of the candidate internal standard elements. It is something.

[0010] Further, an elemental analyzer according to the present invention, which is made to solve the above problems, an internal standard candidate element setting unit that accepts designation of one or more target elements and designation of multiple candidate internal standard elements for measurement of the target elements, and sets internal standard candidate element information that associates the multiple candidate internal standard elements with each of the one or more target elements; a standard sample measurement unit for measuring a plurality of standard samples, each of which contains one or more target elements to be analyzed in known amounts and each of which contains a plurality of candidate internal standard elements associated with the one or more target elements to be analyzed in known amounts, and which have mutually different contents of the target elements to be analyzed; a calibration curve creation unit that creates a calibration curve corresponding to each of the one to more target elements based on the candidate internal standard element information, using the measurement intensities of the candidate internal standard elements obtained by measuring the standard samples and the measurement intensities of the target element; an analyte sample measurement unit for measuring an analyte sample containing unknown amounts of the one or more analyte elements to which the plurality of internal standard candidate elements have been added in predetermined amounts; a quantitative value calculation unit that calculates a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample, the measurement intensities of each of the multiple candidate internal standard elements, and the calibration curve; a quantitative value display unit that displays a quantitative value calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; Equipped with. [Effects of the Invention]

[0011] In the elemental analysis method and elemental analysis apparatus according to the present invention, first, internal standard candidate element information is created, in which one or more analyte elements are associated with multiple internal standard candidate elements. Furthermore, multiple standard samples are prepared, each containing known amounts of one or more analyte elements and known amounts of multiple internal standard candidate elements associated with the one or more analyte elements, but with different contents of the analyte elements. For each standard sample, the one or more analyte elements and the corresponding internal standard candidate elements are measured. The contents of the multiple internal standard candidate elements contained in the standard sample need only be known, and may be the same or different from one another. A calibration curve is then created for each analyte element based on the measured intensities of the analyte element and the multiple internal standard candidate elements obtained by measuring the standard sample. Then, a sample to be analyzed, to which predetermined amounts of multiple internal standard candidate elements have been added, is measured. Quantitative values ​​of each of the multiple internal standard candidate elements are calculated for each analyte element using the measured intensities of the analyte element and the multiple internal standard candidate elements obtained by the measurement, the added amounts of each internal standard candidate element, and the calibration curve. In the present invention, quantitative values ​​for one analyte element are calculated from multiple internal standard candidate elements, so even if any of the quantitative values ​​is abnormal, the abnormal value can be easily detected simply by comparing the multiple quantitative values ​​with each other. The final quantitative value of the analyte element can be determined based on quantitative values ​​calculated from the calibration curves of the other internal standard candidate elements, excluding the abnormal value. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing the configuration of a main part of an inductively coupled plasma mass spectrometer, which is an embodiment of an elemental analysis apparatus according to the present invention. [Figure 2] 1 is a flowchart of an embodiment of an elemental analysis method according to the present invention, using the plasma mass spectrometer of the present embodiment. [Figure 3] 10 is an example of a screen for individually specifying an element to be analyzed and a candidate internal standard element in this embodiment. [Figure 4] 10 is an example of a screen for specifying a candidate internal standard element for each element to be analyzed in this embodiment. [Figure 5] 10 is a display example of calibration curves of multiple internal standard candidate elements in this embodiment. [Figure 6] 10 is a display example of the quantitative values ​​of the elements to be analyzed in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] An inductively coupled plasma mass spectrometer (ICP-MS) as an embodiment of an elemental analysis apparatus according to the present invention will be described below with reference to the drawings.

[0014] 1 is a diagram showing the configuration of the main parts of an inductively coupled plasma mass spectrometer 1 of this embodiment. This inductively coupled plasma mass spectrometer 1 is roughly composed of a plasma ionization section 10, a mass analysis section 30, and a control and processing section 40.

[0015] The plasma ionization unit 10 includes a plasma torch 20, which includes a sample flow tube through which a liquid sample atomized by a nebulizer gas flows, a plasma gas tube formed around the sample flow tube, and a cooling gas tube formed around the plasma gas tube. The sample flow tube is connected to an autosampler 11 that introduces the liquid sample and a nebulizer gas source 12 that supplies a nebulizer gas that atomizes the liquid sample introduced from the autosampler 11. The plasma gas tube is also connected to a plasma gas source 13. The cooling gas tube is also connected to a cooling gas source (not shown) that supplies a cooling gas. Argon gas, for example, is used as the nebulizer gas, cooling gas, and plasma gas. In the plasma ionization unit 10, argon plasma 21 is generated at the tip of the plasma torch 20, and atomic ions are generated from the liquid sample by introducing the atomized liquid sample into the argon plasma 21.

[0016] The mass analysis section 30 comprises a first vacuum chamber 31 having a skimmer formed at the entrance facing the argon plasma 21, and a second vacuum chamber 32 having a skimmer formed between the first vacuum chamber 31 and a quadrupole mass filter 321 and a detector 322 disposed inside for detecting ions separated by the quadrupole mass filter 321.

[0017] The control and processing unit 40 includes a memory unit 41 and, as functional blocks, an internal standard candidate element setting unit 42, a standard sample measurement unit 43, a calibration curve creation unit 44, an analysis target sample measurement unit 45, a quantitative value calculation unit 46, a quantitative value display unit 47, and a quantitative value determination unit 48. The control and processing unit 40 is actually a personal computer, and each of the above functional blocks is realized by executing a pre-installed elemental analysis program on the processor. In addition, an input unit 60 such as a keyboard and mouse, and a display unit 70 such as a liquid crystal display are connected to the control and processing unit 40.

[0018] The memory unit 41 stores in advance information on the measurement conditions for each element (such as the flow rate of the nebulizer gas, the flow rate of the plasma gas, and the mass-to-charge ratio of the ions generated from each element) used when measuring standard samples and samples to be analyzed.

[0019] Next, the procedure for analyzing a sample using the inductively coupled plasma mass spectrometer 1 of this embodiment will be described with reference to the flowchart of FIG.

[0020] The user prepares in advance a plurality of standard samples, each containing a different amount of the element to be analyzed and containing known amounts of a plurality of elements that can be used as internal standard elements, and sets these in the autosampler 11. The standard samples are prepared, for example, by appropriately diluting a commercially available single-element standard solution or mixed standard solution.

[0021] After a standard sample is placed in the autosampler 11, when a command to measure the standard sample is given, the internal standard candidate element setting unit 42 reads out the elements registered in the memory unit 41 and displays a list on the screen of the display unit 70. For example, as shown in FIG. 3, this is displayed as a list in which each element pre-registered in the memory unit 41 is associated with a check box for selecting it as an analyte element and a check box for selecting it as an internal standard candidate element. The internal standard candidate element setting unit 42 prompts the user to specify the analyte element and the internal standard candidate element on this screen. At this time, the internal standard candidate element setting unit 42 prompts the user to select multiple internal standard candidate elements. Note that the element currently selected as the analyte element (As in FIG. 3) cannot be entered into the check box so that it cannot be selected as an internal standard candidate element. The following description will be given using an example in which As (arsenic) and Se (selenium) are specified as the analyte elements and Ga (gallium), Y (yttrium), In (indium), and Te (tellurium) are specified as the internal standard candidate elements.

[0022] When the user specifies an analyte element (As, Se) and multiple internal standard candidate elements (Ga, Y, In, Te) by a predetermined operation such as checking a checkbox and pressing a confirm button (step 1), the internal standard candidate element setting unit 42 sets internal standard candidate element information that associates all of the specified multiple internal standard candidate elements with each specified analyte element (step 2), and saves this information in the memory unit 41. As a result, all possible combinations (2 x 4 = 8 combinations) of the analyte element and the internal standard candidate element are automatically set by the internal standard candidate element setting unit 42 as the internal standard candidate element information.

[0023] The user may use the internal standard candidate element information set here as is, or may narrow down the internal standard candidate elements for each analyte element. For ease of explanation, only two analyte elements and four internal standard candidate elements are selected here, resulting in a total of eight possible combinations. However, if the user specifies a large number of analyte elements and internal standard candidate elements, the number of combinations becomes enormous. In such cases, the user may narrow down the internal standard candidate element information as appropriate. If the mass-to-charge ratio ranges of the elements specified as analyte elements and the mass-to-charge ratio ranges of the elements specified as internal standard candidate elements are both wide, setting the internal standard candidate element information using all possible combinations will include combinations of analyte elements and internal standard candidate elements with large differences in mass-to-charge ratio. The degree to which the analyte element is affected by other ions varies depending on the mass relationship between the analyte element and the other ions, the ionization potential, and other factors. Therefore, it is generally recommended to select elements with masses or ionization potentials similar to those of the analyte element as internal standard candidate elements. Therefore, for each target element, it is advisable to narrow down the internal standard candidate elements to those having a mass-to-charge ratio and / or an ionization potential close to that of the target element.

[0024] After creating all possible combinations of candidate internal standard element information, the candidate internal standard element setting unit 42 displays the combinations on the display unit 70. When the user confirms the displayed candidate internal standard element information and performs a predetermined operation, such as pressing the OK button, the candidate internal standard element setting unit 42 confirms all possible combinations of candidate internal standard element information set in step 2. On the other hand, when the user performs a predetermined operation to instruct editing of the displayed candidate internal standard elements, the candidate internal standard element setting unit 42 displays a screen for changing the candidate internal standard element for each target element. An example of this is shown in FIG. 4. This screen displays a list of target elements and a list of candidate internal standard elements. When the user selects one target element and multiple candidate internal standard elements from the list of candidate internal standard elements, new candidate internal standard element information in which the two elements are associated is stored in the storage unit 41. FIG. 4 shows a state in which the checkbox for Te is cleared from the candidate internal standard elements for As, one of the target elements (Ga, Y, and In are selected as candidate internal standard elements). Pressing the Enter button in this state associates Ga, Y, and In as candidate internal standard elements with the analyte element As. The following explanation will be given using an example in which In has also been excluded from the candidate internal standard elements for the analyte element Se (Ga, Y, and Te have been associated as candidate internal standard elements). In other words, the total of eight combinations of analyte elements and candidate internal standard elements are now narrowed down to six (three each for As and Se).

[0025] Once the internal standard candidate element information is set, the standard sample measurement unit 43 reads out the measurement conditions (mass-to-charge ratio, etc.) for each of the analyte element and the internal standard candidate element from the storage unit 41, creates a method file describing the measurement conditions, and creates a batch file for executing these. In this example, five types of standard samples (one of which is a blank sample containing no analyte element) with different contents (concentrations) of the analyte element are measured in sequence.

[0026] After the standard sample measurement unit 43 has created the batch file, when the user performs a predetermined operation such as pressing a measurement execution button, the standard sample measurement unit 43 sequentially introduces the five types of standard samples set in the autosampler 11 into the plasma torch 20, ionizes them with argon plasma 21, and measures them for each mass-to-charge ratio in the mass analysis unit 30 (step 3). The measurement data obtained by the detector 322 of the mass analysis unit 30 is sequentially transmitted to the control and processing unit 40 and stored in the memory unit 41.

[0027] Upon completion of the measurement of the standard samples, the calibration curve creation unit 44 creates, for each target element, a calibration curve for each target element of the internal standard candidate element associated with that target element, based on the measurement intensities of the target element and the candidate internal standard elements obtained by measuring the five standard samples, and the amounts of the target element and the candidate internal standard elements contained in each standard sample, and displays the created calibration curve on the screen of the display unit 70 (step 4).

[0028] Figure 5 shows an example of a calibration curve created for each internal standard candidate element. This example shows the calibration curves for the measured intensity of the target element, As, when Ga, Y, and In are used as internal standard candidate elements.

[0029] In this example, in addition to the graph of the calibration curve of As created for each internal standard candidate element (top), the set concentration of the analyte element in each of the five standard samples (BLK and STD1 to STD4), the ratio of the measured intensity of the analyte element to the measured intensity of each internal standard candidate element, and the concentration calculated by quantifying the analyte element from the calibration curve based on the intensity ratio are displayed in a table format (bottom).

[0030] The table in Figure 5 has an "Exclude" column and check box, which are used to create a calibration curve by excluding the measurement data of the standard sample, and are not used in the example in Figure 5. Also, the notations CAL1 to CAL5 in the classification column indicate that the standard samples are for creating a calibration curve.

[0031] Thereafter, when the user places the sample to be analyzed in the autosampler 11 and instructs the measurement of the sample to be analyzed, the sample measurement unit 45 reads out the measurement conditions (mass-to-charge ratio, etc.) of the two target elements (As and Se) and the internal standard candidate elements (Ga, Y, In, Te) designated for each target element from the memory unit 41, creates a method file describing the measurement conditions, and creates a batch file for executing them.

[0032] Next, based on the created batch file, the analysis sample measurement unit 45 sequentially introduces the analysis samples set in the autosampler 11 into the plasma torch 20, ionizes them with argon plasma 21, and measures them for each mass-to-charge ratio in the mass analysis unit 30 (step 5). The measurement data obtained by the detector 322 of the mass analysis unit 30 is sequentially transmitted to the control and processing unit 40 and stored in the memory unit 41.

[0033] When the measurement of the analysis samples is completed, the quantitative value calculation unit 46 calculates the quantitative value of the analysis element for each analysis sample based on the measured intensity of the analysis element, the measured intensity of the internal standard candidate element associated with the analysis element, and the calibration curve created for the internal standard candidate element (see FIG. 5) (step 6).

[0034] When the quantitative value calculation unit 46 calculates the quantitative values ​​of each target element contained in each target sample (at this point, the number of quantitative values ​​is the same as the number of candidate internal standard elements associated with each target element), the quantitative value display unit 47 displays these quantitative values ​​on the screen of the display unit 70 (step 7).

[0035] 6 is an example of the display of quantitative values ​​of the analysis target elements by the quantitative value display unit 47. In this example, the quantitative values ​​obtained for each analysis target element and for each internal standard candidate element designated for the analysis target element for four analysis target samples (Blank, N1 to N3) are displayed in table form. Note that the entry UNK in the classification column indicates that the analysis target is an unknown sample group (Unknown).

[0036] The user checks the quantitative values ​​calculated from the calibration curves of the candidate internal standard elements for each of the analyte elements As and Se, and selects one of the candidate internal standard elements that yields the most appropriate quantitative value. Once the candidate internal standard element is selected by the user, the quantitative value determination unit 48 determines the quantitative value obtained from the calibration curve of that candidate internal standard element as the final quantitative value (final quantitative value) of the analyte element (step 8). The quantitative value determination unit 48 also stores the candidate internal standard element selected by the user in the memory unit 41 together with the quantitative value as the internal standard element used to determine the quantitative value of the analyte element. For the analyte element As, three quantitative values ​​have been calculated based on the measured intensities and calibration curves of the three candidate internal standard elements (Ga, Y, and In). Therefore, the user selects one of these as the internal standard element to be used for quantifying the analyte element, and determines the quantitative value calculated from the calibration curve of that internal standard element as the final quantitative value. Furthermore, for the target element Se, three quantitative values ​​have been calculated based on the measured intensities and calibration curves of three candidate internal standard elements (Ga, Y, and Te). The user then selects one of these as the internal standard element to be used for quantifying the target element, and determines the quantitative value calculated from the calibration curve of that internal standard element as the final quantitative value (Step 8).

[0037] In conventional inductively coupled plasma analyzers, when determining an internal standard element for an analyte, a calibration curve is created by associating one internal standard element with each analyte element. After measuring the analyte, quantitative values ​​are calculated using the calibration curve for the corresponding internal standard element. In other words, only one quantitative value is calculated for each analyte element. Therefore, if the measured intensity of the internal standard element becomes abnormal due to reasons such as the presence of a matrix or impurities in the analyte sample that have an unexpected effect on the element selected as the internal standard, only an unskilled technician may notice the abnormality and use an incorrect quantitative value as the analytical result.

[0038] In addition, if a user notices that the quantitative value of an analyte element obtained from the initially selected internal standard element is abnormal, the user has traditionally changed the internal standard element to another one and recalculated the quantitative value of the analyte element. To accomplish this, the user must perform the tedious steps of changing the internal standard element associated with the analyte element to another element, creating a calibration curve for quantifying the analyte element using the new internal standard element, and then calculating the quantitative value of the analyte element using that calibration curve. Similarly, when verifying the validity of a quantitative value of an analyte element calculated from a calibration curve for a certain internal standard element, the user must first calculate the quantitative value, record it, change the internal standard element to another element, create a calibration curve for quantifying the analyte element using the new internal standard element, and then calculate the quantitative value of the analyte element using that calibration curve. This tedious process must also be performed.

[0039] In contrast, in the inductively coupled plasma mass spectrometer 1 of this embodiment, as described above, multiple candidate internal standard elements are specified for one analyte element to set internal standard candidate element information, and a calibration curve is created for each of the multiple candidate internal standard elements from the measurement intensity data obtained by measuring a standard sample. After measuring the analyte sample, a quantitative value is calculated for each analyte element using the calibration curves of the multiple candidate internal standard elements associated with that element. In other words, multiple quantitative values ​​are calculated for each analyte element. The user can simultaneously view and compare the multiple quantitative values ​​calculated in this manner. If the analyte sample contains a matrix or impurities that have an unexpected effect on one of the elements selected as the candidate internal standard element, only the quantitative value calculated from the calibration curve of the affected candidate internal standard element will be an abnormal value, and the abnormality of that value can be easily identified by comparing it with other quantitative values. Furthermore, the correct final quantitative value can be easily determined by simply selecting a normal quantitative value calculated using the calibration curves of other candidate internal standard elements.

[0040] The above embodiment is merely an example and can be modified appropriately in accordance with the spirit of the present invention.

[0041] In the above embodiment, the internal standard candidate element setting unit 42 generates all possible combinations of internal standard candidate element information, then displays the combinations on the display unit 70, allowing the user to narrow down the combinations as needed. However, after the internal standard candidate element setting unit 42 generates all possible combinations of internal standard candidate element information, the measurement of the standard sample may be performed without requiring the user to confirm the information. This allows the internal standard candidate element information to be generated without requiring the user to perform any additional work, and calibration curves can be created for comprehensive combinations of the analyte elements and the internal standard candidate elements. On the other hand, narrowing down the analyte elements and the internal standard candidate elements as in the above embodiment reduces the number of combinations of the analyte elements and the internal standard candidate elements, thereby reducing the burden associated with the process of generating the calibration curve and the process of calculating the quantitative values. Furthermore, in the above embodiment, the combinations of the analyte elements and the internal standard candidate elements are narrowed down before measuring the standard sample. However, this narrowing down may be performed after measuring the standard sample and before measuring the analyte samples in step 5.

[0042] In the above example, the user selects one of the internal standard candidate elements, and the quantitative value calculated from the measured intensity and the calibration curve of that internal standard candidate element is set as the final quantitative value. However, the method for determining the final quantitative value is not limited to this, and can be changed as appropriate, for example, by automatically selecting an internal standard candidate element that satisfies a predetermined criterion and determining the final quantitative value. For example, the predetermined criterion can be the smallest error when creating the calibration curve (the difference between the set concentration in FIG. 5 and the concentration calculated from the calibration curve) or the closest mass to the analyte element.

[0043] Although the above example is an inductively coupled plasma mass spectrometer, the same configuration as above can be adopted in various analytical instruments that use an internal standard element when quantifying the elements to be analyzed, such as an inductively coupled plasma optical emission spectrometry (ICP-OES), which measures the intensity of light emitted from the plasma of elements contained in a liquid sample at wavelengths specific to each element.

[0044] [Aspect] It will be appreciated by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0045] (Section 1) An elemental analyzer according to one aspect of the present invention comprises: an internal standard candidate element setting unit that accepts designation of one or more target elements and designation of multiple candidate internal standard elements for measurement of the target elements, and sets internal standard candidate element information that associates the multiple candidate internal standard elements with each of the one or more target elements; a standard sample measurement unit for measuring a plurality of standard samples, each of which contains one or more target elements in known amounts and each of which contains a plurality of candidate internal standard elements associated with the one or more target elements in known amounts, and which have different contents in the target elements; a calibration curve creation unit that creates a calibration curve corresponding to each of the one to more target elements based on the candidate internal standard element information, using the measurement intensities of the candidate internal standard elements obtained by measuring the standard samples and the measurement intensities of the target element; an analyte sample measurement unit for measuring an analyte sample containing unknown amounts of the one or more analyte elements to which the plurality of internal standard candidate elements have been added in predetermined amounts; a quantitative value calculation unit that calculates a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample, the measurement intensities of the multiple candidate internal standard elements, and the calibration curve; a quantitative value display unit that displays a quantitative value calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; Equipped with.

[0046] (Section 5) Furthermore, an elemental analysis method according to one aspect of the present invention includes: setting internal standard candidate element information in which one or more analysis target elements are associated with a plurality of internal standard candidate elements, measuring a plurality of standard samples each containing one or more target elements to be analyzed in known amounts and each containing a plurality of candidate internal standard elements associated with the one or more target elements to be analyzed in known amounts, the standard samples having mutually different contents of the target elements to be analyzed; based on the information on the internal standard candidate elements, for each of the one to more target elements, creating a calibration curve corresponding to each of the multiple target elements using the measurement intensities of the multiple target elements and the measurement intensities of the target elements obtained by measuring the multiple standard samples; measuring an analysis sample containing unknown amounts of the one or more analysis target elements to which predetermined amounts of the plurality of internal standard candidate elements have been added; calculating a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample and the measurement intensities of each of the multiple candidate internal standard elements, and the calibration curve; displaying the quantitative values ​​calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; For each of the one or more target elements, a final quantitative value is determined based on the quantitative value calculated for each of the candidate internal standard elements. It is something.

[0047] In the elemental analyzer of paragraph 1 and the elemental analysis method of paragraph 5, input specifying one or more analyte elements and multiple internal standard candidate elements is first accepted. Next, internal standard candidate element information is set, in which each analyte element is associated with the specified multiple internal standard candidate elements. This sets internal standard candidate element information containing all possible combinations of analyte elements and internal standard candidate elements. Furthermore, multiple standard samples are prepared, each containing known amounts of one or more analyte elements and known amounts of multiple internal standard candidate elements associated with the one or more analyte elements, but with different contents of the analyte elements. For each standard sample, the one or more analyte elements and the corresponding internal standard candidate elements are measured. The contents of the multiple internal standard candidate elements contained in the standard sample need only be known, and may be the same or different from each other. A calibration curve is then created for each analyte element based on the measured intensities of the analyte element and the multiple internal standard candidate elements obtained by measuring the standard sample. Then, a sample to be analyzed, to which a predetermined amount of each of the multiple candidate internal standard elements has been added, is measured, and a quantitative value is calculated for each of the multiple candidate internal standard elements using the measured intensity of the target element obtained by the measurement, the measured intensities of the multiple candidate internal standard elements, and the calibration curves for each candidate internal standard element. With the elemental analyzer of paragraph 1 and the elemental analysis method of paragraph 5, quantitative values ​​are calculated for one target element from each of the multiple candidate internal standard elements, allowing the user to simultaneously check and compare these quantitative values. Therefore, even if any quantitative value is abnormal, the abnormal value can be easily discovered simply by comparing the multiple quantitative values.

[0048] (Section 2) 2. The elemental analyzer according to claim 1, The internal standard candidate element setting unit accepts, for each analysis target element, designation of a plurality of internal standard candidate elements to be associated with the analysis target element, and sets the internal standard candidate element information.

[0049] The elemental analyzer of paragraph 2 can reduce the number of combinations of the target element and the candidate internal standard element, thereby reducing the load associated with the process of creating a calibration curve and the process of calculating quantitative values.

[0050] (Section 3) The elemental analyzer according to claim 1 or 2, further comprising: a quantitative value determination unit that receives an input for selecting one of the plurality of quantitative values ​​displayed by the quantitative value display unit for each of the one to plurality of analysis target elements, and determines the selected quantitative value as the analysis result; Equipped with.

[0051] In the elemental analyzer of paragraph 3, the user can determine the final quantitative value for each analyte element by simply comparing the quantitative values ​​calculated based on the ratios of the measured intensities of multiple internal standard candidate elements and the calibration curves and selecting one of them. Alternatively, the quantitative value determination unit may extract one internal standard candidate element according to a predetermined criterion and automatically select the quantitative value calculated from that internal standard candidate element. In this case, the predetermined criterion can be, for example, the smallest error in creating the calibration curve (the difference between the set concentration and the concentration calculated from the calibration curve in Figure 5) or the closest mass to the analyte element.

[0052] (Section 4) In the elemental analyzer according to any one of claims 1 to 3, The elemental analyzer is an inductively coupled plasma mass spectrometer or an inductively coupled plasma optical emission spectrometer.

[0053] The configuration of the elemental analyzer described in paragraphs 1 to 3 can be suitably used in an inductively coupled plasma mass spectrometer or an inductively coupled plasma optical emission spectrometer. [Explanation of symbols]

[0054] 1...Inductively coupled plasma mass spectrometer 10...Plasma ionization unit 11...Autosampler 12...Nebulizer gas supply source 13...Plasma gas supply source 20...Plasma torch 21...Argon plasma 30…Mass spectrometry department 31...1st vacuum chamber 32…Second vacuum chamber 321...Quadrupole mass filter 322...detector 40...Control and processing section 41...Storage section 42...Internal standard candidate element setting section 43...Standard sample measurement section 44...Calibration curve creation section 45...Analysis sample measurement section 46...Quantitative value calculation section 47...Quantitative value display section 48...Quantitative value determination unit 60...Input section 70…Display section

Claims

1. an internal standard candidate element setting unit that accepts designation of one or more target elements and designation of multiple candidate internal standard elements for measurement of the target elements, and sets internal standard candidate element information that associates the multiple candidate internal standard elements with each of the one or more target elements; a standard sample measurement unit for measuring a plurality of standard samples, each of which contains one or more target elements in known amounts and each of which contains a plurality of candidate internal standard elements associated with the one or more target elements in known amounts, and which have different contents in the target elements; a calibration curve creation unit that creates a calibration curve corresponding to each of the one to more target elements based on the candidate internal standard element information, using the measurement intensities of the candidate internal standard elements obtained by measuring the standard samples and the measurement intensities of the target element; an analyte sample measurement unit for measuring an analyte sample containing unknown amounts of the one or more analyte elements to which the plurality of internal standard candidate elements have been added in predetermined amounts; a quantitative value calculation unit that calculates a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample, the measurement intensities of the multiple candidate internal standard elements, and the calibration curve; a quantitative value display unit that displays a quantitative value calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; An elemental analyzer comprising:

2. 2. The elemental analyzer according to claim 1, wherein the internal standard candidate element setting unit accepts, for each analysis target element, designation of a plurality of internal standard candidate elements to be associated with the analysis target element, and sets the internal standard candidate element information.

3. moreover, an analysis result determination unit that receives an input for selecting one of the plurality of quantitative values ​​displayed by the quantitative value display unit for each of the one to plurality of analysis target elements, and determines the selected quantitative value as the analysis result; The elemental analyzer according to claim 1 or 2, comprising:

4. 3. The elemental analyzer according to claim 1, which is an inductively coupled plasma mass spectrometer or an inductively coupled plasma optical emission spectrometer.

5. setting internal standard candidate element information in which one or more analysis target elements are associated with a plurality of internal standard candidate elements, measuring a plurality of standard samples each containing one or more target elements to be analyzed in known amounts and each containing a plurality of candidate internal standard elements associated with the one or more target elements to be analyzed in known amounts, the standard samples having mutually different contents of the target elements to be analyzed; based on the information on the internal standard candidate elements, for each of the one to more target elements, creating a calibration curve corresponding to each of the multiple target elements using the measurement intensities of the multiple target elements and the measurement intensities of the target elements obtained by measuring the multiple standard samples; measuring an analysis sample containing unknown amounts of the one or more analysis target elements to which predetermined amounts of the plurality of internal standard candidate elements have been added; calculating a quantitative value of each of the one to multiple target elements using the measurement intensity of the target element obtained by measuring the target sample and the measurement intensities of each of the multiple candidate internal standard elements, and the calibration curve; displaying the quantitative values ​​calculated for each of the one or more target elements for analysis and for each of the candidate internal standard elements; For each of the one or more target elements, a final quantitative value is determined based on the quantitative value calculated for each of the candidate internal standard elements. This is an elemental analysis method.

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