Method and apparatus for predicting interferences in mass spectrometry

Abstract

A method of predicting mass spectrometric interference in a mass spectrometric analysis method using an inductively coupled plasma mass spectrometer is provided. According to the present invention: a mass spectrometric analysis method and an associated response factor are selected from a database in which a plurality of mass spectrometric analysis methods each specifying a mass spectrometric analysis condition and a response factor for each mass spectrometric analysis method indicating a correlation between an element and a signal intensity of the element are stored; an application is selected from an application library in which applications specifying a kind and a content of elements are collected; signal intensities of each element specified in the selected application and signal intensities of interference components corresponding to each element are estimated; and mass spectrometric interference predicted for each element is displayed.

Description

Technical Field

[0001] This invention relates to ICP-MS (Inductively Coupled Plasma Mass Spectrometry), and more specifically, to a method and apparatus capable of assessing the effects of interference on a mass spectrometry analysis method that can be performed in ICP-MS without performing any actual measurements. The method of this invention can be executed according to a computer program, and the computer program can be implemented in an ICP-MS apparatus. Background Technology

[0002] ICP-MS is used to analyze inorganic elements, especially metals present in trace amounts, and is widely used in many fields, including semiconductors, geology, and the environment. ICP-MS can perform essentially simultaneous multi-element analysis of most elements in the periodic table, and can also quantitatively determine element concentrations with excellent sensitivity at the parts-per-billion (ppb) or parts-per-trillion (ppt) level.

[0003] In ICP-MS, an inductively coupled argon plasma at atmospheric pressure is used as the ionization source. Analyte element ions generated in the plasma are introduced into a high-vacuum mass analyzer in the form of a beam via a differential pumping system, where they are separated and determined based on their mass-to-charge ratio (m / z). In one example, the analyte element is dissolved in the sample solution and delivered by a pump, along with an element added as an internal standard, to a nebulizer that generates a sample aerosol. The sample aerosol is supplied to the plasma, where it undergoes desolvation, atomization, and ionization. The resulting element ions are transported from the atmospheric pressure plasma to the mass analyzer through an interface comprising two perforated cones (called the sampling cone and the intercept cone) and an ion lens assembly.

[0004] Due to the aforementioned configuration, when detecting weak signals from target elements, the ICP-MS apparatus may be affected by mass spectrometric interference from argon or coexisting elements in the plasma, potentially leading to signal intensity reduction. Mass spectrometric interference is a phenomenon where components from another source overlap in mass with the analyte being measured, and various types of mass spectrometric interference, such as isotope interference, polyatomic ion interference, and double-charged ion interference, can affect the accuracy of analytical results. Therefore, it is necessary to reduce or eliminate interference through appropriate methods to ensure the reliability of quantitative values.

[0005] To eliminate the effects of mass spectrometry interference, ICP-MS devices typically include a collision / reaction cell downstream of the ion lens assembly. The collision / reaction cell is designed to prevent interference with the measurement signal by introducing a reactant gas (such as hydrogen) or an inert gas (such as helium) with relatively low molecular weight. This allows polyatomic / molecular ions in the incident ion beam to react with the reactant gas molecules and be selectively neutralized, or to collide with the inert gas molecules and lose kinetic energy. In some cases, a device is also used where mass analyzers are arranged in series upstream and downstream of the collision / reaction cell to more selectively eliminate mass spectrometry interference. Summary of the Invention

[0006] Practical measurements using an ICP-MS apparatus require predicting interfering components for each individual sample, selecting the internal standard element to be used, and setting plasma conditions, gas conditions in the collision / reaction cell, integration time in the mass analyzer, etc., to create an analytical method suitable for that sample. If satisfactory results are not obtained, the measurements must be repeated to search for measurement conditions and optimize the method. This is a tedious task that requires a significant amount of time and effort.

[0007] JP-A 2010-169412 discloses a method for semi-quantitative analysis of spectral data from ICP luminescence analysis against a basic database to determine principal component elements. The basic database is modified by extracting information related to the principal component elements from an interference database. Using the modified basic database, the interference level at a predetermined measurement wavelength is calculated, and the interference level and limit of quantitation at that wavelength are displayed. This method analyzes emission spectral data obtained after actual sample measurement and does not disclose any evaluation methods performed without measurement.

[0008] JP-A 2008-45901 describes a technique for automatically determining conditions (such as carrier gas flow rate in aerosols and plasma radio frequency (RF) power) using a computer program, taking advantage of the sensitivity of a specific metal ion and its correlation with that metal oxide ion. This technique is particularly suitable for optimizing plasma conditions to avoid interference based on high matrix samples, but without pre-assessing anticipated interferences in the determination.

[0009] The problem this invention aims to solve is to pre-estimate the spectral interference in a mass spectrometry analysis method feasible in ICP-MS, and the extent to which the spectral interference contributes to the assumed signal intensity of the sample being measured, thereby providing an assessment of the reliability of quantitative results based on this mass spectrometry analysis method without performing actual measurements. Furthermore, another problem this invention aims to solve is to provide the assessment results obtained in this manner to the user in an easily understandable form, and to present information about the assessment content and details where necessary.

[0010] According to one embodiment of the present invention, a method for predicting mass spectrometry interference in a mass spectrometry analysis method used in an inductively coupled plasma mass spectrometry (ICP-MS) analysis apparatus is provided. The method includes: selecting a mass spectrometry analysis method and associated response factors from a database storing multiple mass spectrometry analysis methods, each specifying one or more mass spectrometry analysis conditions, and storing a response factor for each mass spectrometry analysis method, the response factor indicating the correlation between an element and the signal intensity of the element; selecting an application from an application library collecting applications specifying the type and abundance of elements; estimating the signal intensity corresponding to each element specified in the selected application and the signal intensity corresponding to the interfering components of the elements; and displaying the predicted mass spectrometry interference for each element.

[0011] As mentioned above, actual measurements using an ICP-MS device require setting various conditions to create an analytical method. However, according to the present invention, it is possible to predict what kind of mass spectrometry interference will occur when the created mass spectrometry method is executed using an inductively coupled plasma mass spectrometry (ICP-MS) analyzer without performing any actual measurements. A database stored in a memory, hard disk, or the like stores various mass spectrometry analysis methods and their corresponding sets of response factors. Each mass spectrometry analysis method can specify one or more mass spectrometry analysis conditions, including at least one of plasma conditions, cell conditions, and sample introduction conditions. Furthermore, sample uptake time, internal standard element, mass-to-charge ratio used in the mass analyzer, or integration time, etc., can also be specified.

[0012] Plasma conditions may include: RF power conditions; sampling depth, i.e., the positional relationship between the load coil and the sampling cone; central tube gas flow rate, including nebulizer gas, supplementary gas, and dilution / optional gas; central tube gas type, such as commonly used argon, oxygen added in the case of organic samples, and helium considered in the case of laser ablation; and / or wet / dry conditions, such as GC-ICP-MS or LA-ICP-MS conditions.

[0013] Pool conditions, i.e. conditions related to the collision / reaction pool, may include: the use or non-use of pool gas; the type of pool gas (e.g., He, H2, O2, 10% NH3 / He, CH4, or mixtures thereof); and / or interference reduction mechanisms (e.g., KED (kinetic energy discrimination), CID (collision-induced dissociation), and / or reaction), etc.

[0014] Each mass spectrometry analysis method specifies the aforementioned mass spectrometry analysis conditions individually, and the database stores response factors corresponding to each mass spectrometry analysis method. These response factors indicate the correlation between an element and its signal intensity. That is, when a user selects a mass spectrometry analysis method, a corresponding set of response factors is selected. However, the response coefficient can also be modified according to the configuration of the inductively coupled plasma mass spectrometry analysis device, such as whether the mass analyzer is a single quadrupole or a triple quadrupole, or according to the design of the interface and ion optical system.

[0015] The application library can include a collection of applications for different matrices, such as drinking water applications, seawater applications, and sediment / soil extract applications. Each application specifies the type and concentration of elements. Users select the desired application from the library. This application library can also be stored as a database on memory, hard drive, etc. Furthermore, applications can be added or existing applications can be modified as needed.

[0016] When a user selects a mass spectrometry method, the response factor specified for that method is also selected. Furthermore, when a user selects an application, the signal intensities of each element specified in the selected application, as well as the signal intensities of the interfering components corresponding to each element, are estimated. User selections can be made via an input interface (e.g., keyboard or mouse). The signal intensities of the interfering components can be estimated, for example, based on pre-obtained interfering ion information regarding the m / z values ​​and generation rates of compound ions and multiply charged ions generated during the ionization of the elements. Interfering ion information, for example, provides estimated signal intensities of the interfering components for the plasma conditions corresponding to the mass spectrometry method and the cell conditions used in the collision / reaction cell, respectively. Interfering ion information can be stored in a database like other data. The signal intensities of each element specified in the application can be determined by scanning the m / z value range of that element, for example, by multiplying the element concentration specified in the application by the element's response factor and considering isotopic abundance.

[0017] For each element specified in the application, the signal intensity corresponding to the interfering component can be estimated by referring to the types and formation rates of interfering ions, as well as the types and isotopic abundances of isotopes of these elements. Examples of such interfering components include isotopes of other elements, polyatomic / molecular ions originating from other elements, and multivalent ions of other elements. The monovalent ion M, representing the interfering m / z values, is... + The ions, usually known as M ++ MO + MH + MAr + MM + MOH +These are examples of interfering ions. Furthermore, the generation ratio of these interfering ions can be obtained by pre-calculating the ratio of the signal from a sample of known concentration to the signal of the resulting interfering ions. In one embodiment, the types and generation ratios of interfering ions can be pre-listed for each element and stored as a table in the computer's memory for reference. Since the generation rate of interfering ions may vary depending on the mass spectrometry analysis conditions, multiple tables indicating the generation rate of interfering ions can be prepared based on plasma conditions, cell gas conditions, etc. The signal intensity of each interfering ion can be estimated by multiplying the corresponding element concentration specified in the application by the generation ratio of the interfering ion.

[0018] Since the types and abundances of isotopes for each m / z value are known, the signal intensity of each isotope can be estimated by multiplying the signal intensity of the element containing that isotope by its corresponding isotopic abundance. In this way, the signal intensity corresponding to each element and the signal intensity corresponding to the interfering components of each element can be estimated, and the predicted mass spectrometry interference for each element can be displayed.

[0019] The predicted mass spectrometry interference for each element can be displayed as an interference level. The interference level is based on a comparison between the signal intensity corresponding to each element and the signal intensity corresponding to the interfering component of each element. For example, it can be displayed as a percentage, a star rating, and / or a heatmap. This allows users to understand the impact of the interference at a glance.

[0020] The predicted mass spectrometry interferences for each element can be displayed alongside a periodic table image. For example, heatmaps or coloring can be applied to each element in the periodic table to provide a visual and intuitive understanding of the impact of the interferences.

[0021] According to another embodiment of the present invention, a computer program is provided for predicting mass spectrometry interferences in a mass spectrometry method used in an inductively coupled plasma mass spectrometry (ICP-MS) analyzer. In one embodiment, the computer program causes a computer to perform the following steps: selecting a mass spectrometry method and associated response factors from a database storing multiple mass spectrometry methods, each specifying one or more mass spectrometry conditions, and storing a response factor for each mass spectrometry method, the response factor indicating the correlation between an element and the signal intensity of the element; selecting an application from an application library collecting applications specifying the type and abundance of elements; estimating the signal intensity corresponding to each element specified in the selected application and the signal intensity corresponding to the interfering components of the elements; and displaying the predicted mass spectrometry interferences for each element. The estimation step may include: estimating the signal intensity corresponding to the interfering components based on a table storing pre-obtained information on the m / z values ​​and generation rates of compound ions and multiply charged ions generated during the ionization of the elements. The step may further include the step of: correcting the response factors according to the device configuration of the ICP-MS analyzer.

[0022] The computer program may be provided as a downloadable program from a storage medium or via a network, or it may be executed via a network without downloading. The computer program may also be implemented in an ICP-MS device and can be used to enable the mass spectrometry analysis method to be used in practical measurements after evaluation.

[0023] In terms of apparatus, the present invention can be an apparatus for predicting mass spectrometric interferences in a mass spectrometry method used in an inductively coupled plasma mass spectrometry (ICP-MS) analyzer. The apparatus, for example, is operatively connected to the ICP-MS analyzer. That is, the apparatus can be connected to operate in association with the ICP-MS analyzer, and can be built into the ICP-MS analyzer itself or externally connected to it.

[0024] In one embodiment, the apparatus includes: a database storing multiple mass spectrometry methods, each specifying one or more mass spectrometry analysis conditions, and storing a response factor for each mass spectrometry method, the response factor indicating the correlation between an element and the signal intensity of the element; and an application library collecting applications specifying the types and amounts of elements. The apparatus may include a processor, such as a CPU. The processor is capable of performing processing including: selecting a mass spectrometry method and associated response factor from the database, selecting an application from the application library, and estimating the signal intensity corresponding to each element specified in the selected application and the signal intensity corresponding to the interfering components of each element. This enables the prediction of mass spectrometry interference for each element and the display of the predicted mass spectrometry interference on a display. The processing may further include correcting the response factor according to the apparatus configuration of the inductively coupled plasma mass spectrometry analysis apparatus.

[0025] According to the present invention, users can evaluate the interference effects in a predetermined or desired application for existing or desired mass spectrometry analysis methods without performing any actual measurements. Based on this evaluation, users can modify, for example, plasma conditions, tuning conditions of the collision / reaction cell, etc., to improve the mass spectrometry analysis method. This reduces the time required to create a mass spectrometry analysis method in ICP-MS, while also facilitating the development of methods that provide reliable results and improving the analytical accuracy and reliability of quantitative results. Attached Figure Description

[0026] [ Figure 1 ] Figure 1 This is a schematic diagram illustrating an example of an apparatus capable of performing mass spectrometry analysis as conceived by the prediction method according to the present invention. [ Figure 2 ] Figure 2 This is a flowchart illustrating an exemplary algorithm according to one embodiment of the present invention. [ Figure 3 ] Figure 3 This is a graph illustrating exemplary response factors that can be used in this invention, showing examples of response coefficients under helium mode and high-sensitivity plasma conditions. [ Figure 4 ] Figure 4 This is a table illustrating exemplary applications that can be used in this invention. [ Figure 5 ] Figure 5 This is a flowchart depicting an algorithm for estimating mass spectrometry interference according to one embodiment of the present invention. [ Figure 6 ] Figure 6 This is an example display of prediction results shown in association with an image of the periodic table. [ Figure 7 ] Figure 7 This is another example of a prediction result displayed in association with an image of the periodic table. [ Figure 8 ] Figure 8 This is yet another example of a prediction displayed in association with a periodic table image. [ Figure 9 ] Figure 9 This is a table illustrating an exemplary relationship between interference levels and reliability. Detailed Implementation

[0027] Figure 1 This is a schematic diagram illustrating an example of a mass spectrometry apparatus capable of performing mass spectrometry analyses contemplated by the prediction method according to the invention. While such an apparatus is not actually used for measurements during the implementation of the invention, it can be used for practical measurements once a useful mass spectrometry analysis method is finally obtained.

[0028] Figure 1 The ICP mass spectrometry analysis apparatus 100 shown includes: an inductively coupled plasma ion source 130; an interface 140 for extracting elemental ions generated from the sample from the plasma; an ion lens assembly 150 for accelerating the extracted ions and delivering them as an ion beam; a collision / reaction cell 160 disposed downstream of the ion lens assembly; a mass filter 170 for separating elemental ions according to their mass; and a detector 180.

[0029] In the sample collection unit 110, a peristaltic pump 111 draws the sample 112 from the vial and delivers it to the nebulizer 121, which extends from one end of the temperature-controlled nebulization chamber 122 provided in the sample introduction unit 120. The sample collection unit 110 may include multiple vials, each containing the sample to be measured, various standard solutions, tuning solutions, calibration solutions, rinsing solutions, etc., and can automatically switch between them. The nebulizer 121 uses high-pressure argon (Ar) gas to atomize the sample to form a sample aerosol. This aerosol is blown into the ion source 130 after large droplets are removed by the nebulization chamber 122.

[0030] Ion source 130 has an ICP torch 131. This torch includes a series of concentric quartz tubes through which argon gas flows, these tubes being disposed within an RF coil 132. The RF magnetic field generated by the coil excites Ar atoms passing through the torch, thereby enabling the generation and maintenance of a high-energy plasma. Sample aerosol is blown into the plasma, where it undergoes desolvation, atomization, and ionization.

[0031] In interface 140, ions are extracted from the plasma via sampling cone 141 and intercept cone 142. The extracted ions are then accelerated by ion lens assembly 150 and delivered as an ion beam into a collision / reaction cell 160 located downstream of ion lens assembly 150. Ion lens assembly 150 may include extraction electrode 151, a series of focusing lenses 152, and an off-axis mounted omega lens 153. Gas may be introduced into collision / reaction cell 160, as indicated by reference numeral 161. Such cells are known to remove polyatomic molecular ions from the incident ion beam that could interfere with the mass spectrometry, such as those comprising elements derived from carrier gas, plasma gas, and auxiliary gas, through charge transfer reactions and kinetic energy reduction induced by collisions with gas molecules. Cell 160 may also include a multi-electrode arrangement, such as a quadrupole mass filter 162.

[0032] A mass analyzer, including a mass filter 170 and a detector 180, is positioned downstream of the collision / reaction cell. The mass filter 170 may include, for example, a quadrupole mass filter 171, comprising four parallel rods to which an RF and DC voltage are applied. For any given combination of RF and DC voltage applied to the rods, the mass filter delivers only ions with a specific mass-to-charge ratio to the detector 180. This allows ions of different elements to be separated by the mass filter and then measured by the detector 180. The detector 180 includes an electron multiplier tube detector 181 positioned immediately downstream of the mass filter. The ion signal at each mass-to-charge ratio is amplified and then measured using a multichannel counting device. The elemental signal intensity (in counts per second (CPS)) measured within a specified integration time is proportional to the concentration of that element in the sample solution.

[0033] The sample acquisition unit 110, sample introduction unit 120, inductively coupled plasma ion source 130, collision / reaction cell 160, mass filter 170, and other components can all be controlled by the system controller of the ICP mass spectrometry analyzer, which in turn can be controlled by a computer (such as a personal computer). The method of the present invention can be implemented as a computer-executed program. The computer configured to execute such a program and the ICP mass spectrometry analyzer 100 including such a computer also fall within the scope of the apparatus of the present invention.

[0034] That is, according to one example, the method according to the invention can be implemented as follows: Figure 1The computer program executed by the illustrated personal computer predicts mass spectrometry interferences in a mass spectrometry analysis method that can be executed using the apparatus configuration of the illustrated inductively coupled plasma mass spectrometry analysis device. For example, a database incorporated into or connected to the personal computer via a wired or wireless connection can store multiple mass spectrometry analysis methods, each specifying one or more mass spectrometry analysis conditions, and for each mass spectrometry analysis method, storing response factors indicating the correlation between elements and the signal intensities obtained for those elements.

[0035] The database may include an application library that collects applications specifying element types and concentrations. The application library may include multiple applications with different matrix elements, such as drinking water applications, seawater applications, and sediment / soil extract applications. Users can add or modify applications as needed.

[0036] The user, via an input interface, instructs the computer (processor) to select mass spectrometry analysis methods and associated response factors from a database, and to choose applications from an application library. The computer then executes processing according to the program to estimate the signal intensity corresponding to each element specified in the selected application, as well as the signal intensity corresponding to the interfering components of each element. The processing results, i.e., the predicted mass spectrometry interference for each element, can be displayed on the personal computer's monitor or... Figure 1 The monitor screen of the ICP-MS device shown. Example

[0037] Figure 2 A basic flowchart of an algorithm according to an embodiment of the present invention is shown. As described above, when a mass spectrometry analysis method and application specifying a predetermined response factor are selected from a database, the signal intensity at each mass-to-charge ratio within a predetermined m / z value range is calculated based on the response factor. That is, the database stores the response factor. The response factor indicates the correlation between an element and its signal sensitivity. The correlation depends on the cell gas conditions (e.g., no-gas mode, helium mode, high-energy helium mode, and hydrogen mode), plasma conditions, sample introduction conditions (including lens configuration), and other conditions.

[0038] For example, while low-temperature plasma has advantages such as suppressing carrier gas ionization, reducing background noise, and improving the sensitivity of light elements, it also has disadvantages. Specifically, for samples with high matrix content, the matrix effect becomes more pronounced, and elements with high ionization potentials are less likely to be ionized. The response factor defines the relationship between each element and its signal sensitivity, taking into account the above conditions. This invention obtains estimated values ​​of the signals of each element and the signals of interfering components under the various conditions described above. Figure 3 The example shown illustrates the response coefficients under helium mode and high-sensitivity plasma conditions. The Y-axis represents the signal strength per unit concentration (CPS), and the X-axis represents the atomic number.

[0039] Let F SQ (E) represents the response factor of each element E. The response factor F of each isotope i [m / z] of element E. SQ (i) The calculations are as follows. It should be noted that all the following calculations can be performed using the processors, memory, latches, registers, and other known components described above. Where Abd(i,E) represents the relative abundance of each isotope i [m / z] of element E. The signal intensity I(i,E) of each isotope i [m / z] of element E is calculated as follows: Where C(E) is the concentration of element E, which can be obtained from the application selected by the user (such as drinking water application, seawater application, sediment extract application, or soil extract application), or it can be any value corresponding to that application. Figure 4 The application of seawater is shown as an example.

[0040] Therefore, the signal strength I(M) for each mass-to-charge ratio M is calculated as follows: For example, the signal strength at m / z 50 includes contributions from titanium, vanadium, and chromium isotopes, calculated as follows:

[0041] Next, the signal intensity of each mass spectrometry interference component is calculated for all m / z values. Figure 5 A flowchart illustrating the calculation of the signal intensity generated by the mass spectrometry interference component for each m / z value is shown. The signal intensity generated by the mass spectrometry interference component can be calculated using the signal intensities contained in a dataset pre-obtained for all m / z values. For each m / z value, the mass spectrometry interference component originating from the element can be identified based on the generation rate. The generation rate is defined for each element based on pre-defined actual measurements for each condition setting, including cell gas and plasma conditions. The signal intensity I of the mass spectrometry interference component originating from the source element is shown. n (M) can be calculated as follows: Among them, M source R(n) represents the m / z value corresponding to the source element and the generation rate of the mass spectrometry interference component.

[0042] Examples of interfering components include polyatomic / molecular ions originating from other elements, and multivalent ions from other elements. Monovalent ions M, which interfere with each m / z value, are another example. + The ions, M is known ++MO + MH + MAr + MM + MOH + Furthermore, since the types and isotopic abundances of isotopes at each m / z value are known, the signal intensity of each isotope as an interfering component, expressed in CPS, can be estimated by multiplying the signal intensity of the element having that isotope by the corresponding isotopic abundance. When M[m / z] cannot be identified as corresponding to a specific element and an isotope exists at that m / z value, the signal contribution from each isotope can be calculated. The signal intensity I′(M) used for calculation... i The following can be calculated: Where I(M) i, j () is the signal intensity of each isotope calculated based on isotopic abundance. E represents the set of elements containing such isotopes. For example, a mass-to-charge ratio of 50 m / z represents a set of titanium, vanadium, and chromium.

[0043] Therefore, the total signal intensity I of the mass spectral interference component that may be superimposed on the signal at the mass-to-charge ratio M [m / z] intfs (M) is calculated as follows: Where I n This represents the signal intensity of a single mass spectrometry interference component. The expected total signal intensity I measured at the mass-to-charge ratio M [m / z] is... meas (M) can be calculated as follows:

[0044] Next, the concentration corresponding to each m / z value is calculated. Let I(M iso ) represents the isotope M corresponding to a certain element. iso Signal strength at [m / z]. I(M iso Based on the basic m / z value M base The signal strength at a given location is calculated, and this fundamental m / z value is the m / z value of a representative isotope of the element. Let A(M) iso ) represents isotope M iso The natural isotopic abundance of [m / z], and I(M base ) represents the basic m / z value M defined for this element. base The signal strength at that location. At this time, I(M) iso The calculation is as follows: The intensity used in the calculation needs to exceed the minimum count I. min .

[0045] Count the number of isotopes that meet the following conditions:

[0046] When the number of isotopes is 1, isotope M iso [m / z] is considered to represent the majority of the signal at the m / z value M, and has this isotope M iso The "element" in [m / z] refers to the element predicted for the m / z value M. In other cases, the m / z value M cannot be identified as corresponding to a specific element. For an m / z value M that can be identified as corresponding to a specific element, the corresponding concentration C(M) is calculated as follows:

[0047] exist Figure 3 In the illustrated procedure, the determination reliability of each m / z value is ultimately predicted based on potential interferences. That is, the potential interferences at each m / z value can be assessed based on the signal intensity of the mass spectrometry interference components obtained as described above. This assessment can be performed, for example, based on the interference level [%].

[0048] The interference level IL(M) [%] was calculated as the total signal intensity I of the mass spectrometry interference component expected to be measured at the target m / z value. intfs (M) relative to signal strength I meas The ratio of (M).

[0049] According to the present invention, all m / z values ​​for which the signal strength has been calculated can be evaluated based on the interference level. Figure 9 An example is shown showing the relationship between interference level and reliability, where the interference level is divided into five levels.

[0050] exist Figures 6 to 9 In each of the figures, the interference levels obtained in this way are displayed together with the periodic table image. The prediction results for each element (i.e., Cr, Ti, and S) are also displayed in relation to the interference levels. Therefore, according to the present invention, the reliability of the determination to be performed for elements with determined m / z values ​​can be understood at a glance, and the details of the evaluation results for each element can also be understood. Furthermore, the evaluation results for individual elements can be configured to be displayed by selecting the corresponding element on the periodic table image with a pointer or on a touch panel.

[0051] Figure 6For seawater applications, the reliability predictions for all elements to be measured are shown on the periodic table in dark gray (no problem: see Cr, Mn, Fe, etc.) or under lines (warning level: see Ni, Cu, Zn, etc.). This example clearly and intuitively illustrates the extent to which interferences are superimposed on each isotope for each element. It also displays the interference levels for each isotope of Cr and information on interfering ions for the selected isotopes.

[0052] exist Figure 7 In the middle, with Figure 6 Similarly, predictions for drinking water applications are shown on the periodic table using dark gray and diagonally lined cells. For titanium, predictions for m / z 47 and 49 are shown. The results indicate no overlap interference at m / z 47, while strong overlap interference caused by sulfur exists at m / z 49. Figure 8 In the study, a five-level grayscale heatmap was used to display the predicted results for drinking water applications on the periodic table, showing a high predicted concentration of sulfur. Industrial applicability

[0053] The interference prediction method and apparatus provided by this invention can be widely applied in the field of mass spectrometry analysis, including the selection of useful mass spectrometry analysis methods. List of reference numerals

[0054] 100 Inductively Coupled Plasma Mass Spectrometry Analyzer 110 Sample Collection Department 120 Sample Introducing Section 130 Inductively Coupled Plasma Ion Source 140 interface 150 Ion Lens Assembly 160 Collision / Reaction Pool 170 quality filter 180 detector

Claims

1. A method for predicting mass spectrometry interferences in a mass spectrometry analysis method used in an inductively coupled plasma mass spectrometry analysis apparatus, the method comprising: Select a mass spectrometry analysis method and associated response factor from a database that stores multiple mass spectrometry analysis methods, each specifying one or more mass spectrometry analysis conditions, and stores a response factor for each mass spectrometry analysis method, the response factor indicating the correlation between an element and the signal intensity of the element; Select an application from the application library, which collects applications with specified types and amounts of elements; Estimate the signal strength corresponding to each element specified in the selected application and the signal strength corresponding to the interference components of each element; as well as This displays the predicted mass spectrometry interference for each of the elements.

2. The method according to claim 1, wherein, The mass spectrometry analysis conditions include at least one of plasma conditions, cell conditions, and sample introduction conditions.

3. The method according to claim 2, wherein, The plasma conditions include radio frequency power conditions, sampling depth, central tube gas flow rate, central tube gas type, and / or wet / dry conditions.

4. The method according to claim 2, wherein, The pool conditions include whether or not pool gas is used, the type of pool gas, and / or interference reduction mechanisms.

5. The method according to claim 1, wherein, The response factor is corrected according to the device configuration of the inductively coupled plasma mass spectrometry analysis apparatus.

6. The method according to claim 1, wherein, The application library includes multiple applications with different base elements.

7. The method according to claim 6, wherein, The applications include drinking water applications, seawater applications, and sediment / soil extract applications.

8. The method according to claim 1, wherein, Based on the comparison between the signal intensity corresponding to each element and the signal intensity corresponding to the interference component of each element, the predicted mass spectrometry interference for each element is displayed in the form of interference level.

9. The method according to claim 8, wherein, The display format for the interference level includes percentage display, star rating display, and / or heatmap.

10. The method according to claim 1, wherein, The predicted mass spectrometry interferences for each element are displayed together with an image of the periodic table.

11. The method according to claim 1, wherein, Based on the pre-obtained m / z values ​​and generation rates of the compound ions and multiply charged ions generated during the ionization process of each element, the signal intensity corresponding to the interference component is estimated.

12. The method according to claim 11, wherein, The interfering ion information was obtained for various condition settings, including plasma conditions and measurement conditions used in the collision / reaction cell.

13. A computer program for predicting mass spectrometric interferences in a mass spectrometry method used in an inductively coupled plasma mass spectrometry analysis apparatus, the computer program causing a computer to perform the following steps: Select a mass spectrometry analysis method and associated response factor from a database that stores multiple mass spectrometry analysis methods, each specifying one or more mass spectrometry analysis conditions, and stores a response factor for each mass spectrometry analysis method, the response factor indicating the correlation between an element and the signal intensity of the element; Select an application from the application library, which collects applications with specified types and amounts of elements; Estimate the signal strength corresponding to each element specified in the selected application and the signal strength corresponding to the interference components of each element; as well as This displays the predicted mass spectrometry interference for each of the elements.

14. The computer program according to claim 13, wherein, The estimation step includes estimating the signal intensity corresponding to the interference component based on a table, which stores pre-obtained information on the m / z values ​​and generation rates of the compound ions and multiply charged ions generated during the ionization process of each element.

15. The computer program according to claim 13, wherein, The step further includes the following step: correcting the response factor according to the device configuration of the inductively coupled plasma mass spectrometry analysis device.

16. An apparatus for predicting mass spectrometric interferences in a mass spectrometry method used in an inductively coupled plasma mass spectrometry (ICP-MS) analyzer, the apparatus comprising: The database stores multiple mass spectrometry analysis methods, each specifying one or more mass spectrometry analysis conditions, and stores a response factor for each mass spectrometry analysis method, the response factor indicating the correlation between an element and the signal intensity of the element; Application library, which collects applications that specify the types and amounts of elements; A processor capable of performing processing including: selecting a mass spectrometry analysis method and associated response factor from the database, selecting an application from the application library, and estimating the signal intensity corresponding to each element specified in the selected application and the signal intensity corresponding to the interference component of each element. as well as A display for showing the predicted mass spectrometry interference for each of the elements.

17. The apparatus of claim 16, further comprising: The table stores pre-obtained information on the m / z values ​​and generation rates of interfering ions of compound ions and multiply charged ions generated during the ionization process of each element.

18. The apparatus according to claim 16, wherein, The process further includes: correcting the response factor according to the device configuration of the inductively coupled plasma mass spectrometry analysis device.

19. The apparatus according to claim 16, wherein, The device is operatively connected to the inductively coupled plasma mass spectrometry (ICP-MS) analyzer.

Images