Particle analysis system, particle analysis method, particle purification device, and method for producing purified particle-containing solution

Abstract

Provided is a particle analysis system with which particles in a sample solution can be analyzed with high accuracy. A particle analysis system 100A comprises, as main parts: a particle purification device 1A; a sample solution supply unit 2 that supplies a sample solution containing particles to be analyzed to the particle purification device 1A; an extraction liquid supply unit 3 that supplies an extraction liquid to the particle purification device 1A; and an analysis device 4 that analyzes particles contained in the sample solution discharged from the particle purification device 1A. The particle purification device 1A extracts and removes dissolved ions from a sample solution containing particles and dissolved ions, by passing the dissolved ions through an ion permeable membrane. The analysis device 4 is an ICP-MS device, and can perform particle analysis by a single particle inductively coupled plasma mass spectrometry method.

Description

PARTICLE ANALYSIS SYSTEM AND PARTICLE ANALYSIS METHOD, PARTICLE REFINING DEVICE AND METHOD FOR MANUFACTURING A REFINED PARTICLE-CONTAINING SOLUTION

[0001] (Citation of Related Applications) This application claims the benefit of and priority to Japanese Patent Application No. 2023-140724, filed on August 31, 2023. Priority to the aforementioned patent application is expressly claimed, and the entire disclosure of that application is incorporated herein by reference for all purposes.

[0002] The present disclosure relates to particle analysis systems and methods for analyzing particles in a solution, particle purification devices and methods for producing purified particle-containing solutions, and in certain embodiments, to analytical techniques in single particle inductively coupled plasma mass spectrometry (SP-ICP-MS).

[0003] In recent years, advances in nanotechnology have led to the development of a variety of nanomaterials, whose applications are expanding into a wide range of fields. As a result, there is an increasing demand for measuring these diverse nanomaterials. Meanwhile, inductively coupled plasma mass spectrometry (ICP-MS), which can detect metal elements in solution with high sensitivity, is widely used for impurity analysis in various industries, including semiconductors, pharmaceuticals, chemicals, and the environment. Furthermore, a method for measuring the particle size distribution of nanoparticles, a type of nanomaterial, has been established using ICP-MS; this method is known as single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS).

[0004] SP-ICP-MS is an analytical technique based on the fact that the size of ion clusters varies depending on particle size when particles are ionized by plasma and introduced into a mass spectrometer, and by measuring changes in ion signals in an extremely short period of time, it is possible to obtain peak signals corresponding to particle size. Measurements using SP-ICP-MS can obtain information on particle size from the height of the peak signal (signal intensity), and information on the number of particles from the number of peak signals, thereby obtaining the particle size distribution of particles in a sample solution.

[0005] On the other hand, when dissolved ions are present in a sample solution together with the particles to be analyzed, the accuracy of particle measurement may be reduced due to signals (noise) derived from the dissolved ions, depending on the type of dissolved ions. This problem is particularly pronounced when the dissolved ions contain the same metal element as the metal element contained in the particles to be analyzed. Small peak signals derived from small particles may be buried in the signals (noise) derived from the dissolved ions and become indistinguishable, resulting in a significant reduction in particle measurement accuracy. Therefore, an improvement in this regard has been desired.

[0006] As a method for improving the decrease in measurement accuracy of particles resulting from such dissolved ions, Patent Document 1 reports a method in which measurement data obtained by the SP-ICP-MS method is statistically processed to separate particle signal portions from ion signal portions.

[0007] Japanese Patent Application Laid-Open No. 2020-68202

[0008] One aspect of an embodiment of the present disclosure is a particle analysis system having a particle purification device that extracts and removes dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane, and an analysis apparatus that analyzes the particles contained in the sample solution from which the dissolved ions have been removed by the particle purification device.

[0009] Another aspect of an embodiment of the present disclosure is a method for analyzing particles, which uses a particle purification device equipped with an ion-permeable membrane to remove dissolved ions from a sample solution containing particles and the dissolved ions, and then analyzes the solution with an analytical instrument.

[0010] Furthermore, one aspect of an embodiment of the present disclosure is a particle purification device having a sample solution flow path through which a sample solution containing particles and dissolved ions flows, at least one extract flow path through which an extract flow path flows, and at least one ion-permeable membrane, wherein the sample solution flow path and the extract flow path are positioned opposite each other via the ion-permeable membrane, and the dissolved ions contained in the sample solution are extracted and removed into the extract.

[0011] Furthermore, one aspect of an embodiment of the present disclosure is a method for producing a purified particle-containing solution, in which a sample solution containing the particles to be purified and the dissolved ions is circulated through the sample solution flow path of the above-mentioned particle purification device, while the extract is circulated through the extract flow path, thereby moving the dissolved ions into the extract in the extract flow path and removing the dissolved ions from the sample solution.

[0012] 1A is a conceptual diagram of a particle analysis system 100A of a first embodiment equipped with a particle purification device 1A. FIG. 1B is a conceptual cross-sectional view of the particle purification device 1A. FIG. 1C is an explanatory diagram of dissolved ion removal from a sample solution using the particle purification device 1A. FIG. 1D is an explanatory diagram of a signal obtained when particles are detected in ICP-MS measurement. FIG. 1E is an explanatory diagram of a signal obtained when dissolved ions are detected in ICP-MS measurement. FIG. 1F is an explanatory diagram of a signal obtained when particles and dissolved ions are detected in ICP-MS measurement. FIG. 1G is a conceptual diagram of a particle analysis system 100B of a second embodiment equipped with a particle purification device 1B. FIG. 1H is a conceptual cross-sectional view of the particle purification device 1B. FIG. 1I is an explanatory diagram of dissolved ion removal from a sample solution using the particle purification device 1B. FIG. 1J is a diagram showing the particle recovery rates of Experimental Example 2 (cellulose membrane) and Experimental Example 3 (PTFE membrane). FIG. 1J is an ICP-MS measurement result of the sample solution of Experimental Example 4. FIG. 1J is an enlarged view of FIG. 10. FIG. 1J is an ICP-MS measurement result of the sample solution of Experimental Example 5. FIG. 1J is an enlarged view of FIG. Fig. 1 is a diagram showing the correlation between Al ion concentration and the signal intensity of an ion signal and ion removal rate. Fig. 2 is a diagram showing the correlation between Al ion concentration and the lower limit of particle particle size detection. Fig. 3 is a diagram showing the ICP-MS measurement results of the sample solution of Experimental Example 7. Fig. 4 is a diagram showing the correlation between particle purification treatment voltage and ion removal rate.

[0013] The method of separating particle signal portions from ion signal portions described in Patent Document 1 is merely data processing, and cannot directly remove dissolved ions present in the sample solution, so there are limitations to improving the accuracy of particle measurement.

[0014] Therefore, it is expected to provide a particle analysis system and particle analysis method that extract and remove dissolved ions from a sample solution containing particles and dissolved ions, and analyze the sample solution containing purified particles, as well as a particle purification device that extracts and removes dissolved ions from a sample solution containing dissolved ions, and purifies the sample solution containing particles.

[0015] Hereinafter, the present disclosure will be described in detail with reference to the following embodiments. However, the present disclosure is not limited to the following embodiments. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from the actual ones. Furthermore, the drawings may include portions in which the dimensional relationships and ratios of elements differ from one another.

[0016] Furthermore, when the expression "~" is used in this specification, it is used as an expression that includes the numerical values ​​before and after it. Furthermore, in this specification, the expression "A and / or B" includes "A only," "B only," and "both A and B."

[0017] <1. Particle Analysis System> The particle analysis system of the present disclosure is a particle analysis system (hereinafter referred to as "the particle analysis system of the present disclosure" or simply "particle analysis system") that includes a particle purification device that extracts and removes dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane, and an analysis apparatus that analyzes the particles contained in the sample solution from which the dissolved ions have been removed by the particle purification device.

[0018] The particle analysis system of the present disclosure can be used in a particle analysis method in which dissolved ions are removed from the sample solution using a particle purification device equipped with an ion-permeable membrane. In the particle analysis method using the particle analysis system of the present disclosure, at least one of the size, composition, and concentration of particles in the sample solution is determined.

[0019] In this specification, the term "ion-permeable membrane" refers to a membrane that allows ions to pass through but does not allow particles to pass through. Details of the ion-permeable membrane used in the particle purification device will be described later.

[0020] The particle analysis system of the present disclosure can purify particles in a sample solution by removing dissolved ions contained in the sample solution in a particle purification device, thereby improving the accuracy of analysis of particles to be analyzed by an analytical device.

[0021] In this specification, "purifying particles in a sample solution" means removing dissolved ions in the sample solution and reducing the concentration of dissolved ions to increase the purity of the particles. In other words, purifying particles in a sample solution does not only mean completely removing dissolved ions from the sample solution, but also includes removing some of the dissolved ions from the sample solution.

[0022] In conventional particle analysis systems, when dissolved ions are present in a sample solution containing particles to be analyzed, these dissolved ions can become measurement noise (background), reducing measurement accuracy. This reduction in measurement accuracy is particularly pronounced when the dissolved ions to be removed contain the same metal element as the particles. In contrast, the particle analysis system of the present disclosure uses a particle purification device to extract and remove dissolved ions from the sample solution by passing them through an ion-permeable membrane, even when dissolved ions are present in the sample solution, thereby improving measurement accuracy.

[0023] The type of particles to be analyzed is not particularly limited as long as it can be analyzed using the particle analysis system of the present disclosure, but is typically particles containing metals or metal compounds (metal oxides, metal hydroxides, metal nitrides, metal carbides). Examples of types of particles to be analyzed include metals such as aluminum, gold (Au), silver (Ag), copper (Cu), and nickel; metal oxides such as aluminum oxide, zinc oxide, magnesium oxide, titanium oxide, and silicon oxide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; metal nitrides such as aluminum nitride, silicon nitride, and boron nitride; and metal carbides such as boron carbide, titanium carbide, and silicon carbide. The particles to be analyzed may be of one type or a mixture of two or more types. Furthermore, the particles to be analyzed may have a surface modified.

[0024] Furthermore, the size (particle size) of the particles to be analyzed is not particularly limited as long as it can be analyzed by the particle analysis system of the present disclosure, and although it depends on the type of analysis device used, it is typically 2 nm to 500 nm. When the analysis device is an ICP-MS device, the size (particle size) of the particles to be analyzed is, for example, 10 nm to 200 nm.

[0025] The dissolved ions to be removed are not particularly limited, but examples include alkali metal ions, alkaline earth metal ions, various metal ions such as aluminum, gold, silver, copper, and nickel, carboxylate ions such as formic acid, acetic acid, succinic acid, citric acid, and oleic acid, and organic ions such as polyethyleneimine and polyethylene glycol derivatives.

[0026] When the dissolved ions to be removed are dissolved ions containing the same metal element as the particles, the improvement in measurement accuracy in the particle analysis system of the present disclosure is remarkable. Here, "dissolved ions containing the same metal element as the particles" refers to M ions when the particles to be analyzed contain a metal (including alloys) or metal compound (typically metal oxide) containing the metal element M. For example, when the particles to be analyzed are iron oxide (Fe2O3) particles, Fe ２＋ and Fe 3＋ In the present disclosure, the combination of the particles to be analyzed and the dissolved ions to be analyzed that contain the same metal element as the particles to be analyzed is not particularly limited as long as it improves the measurement accuracy, but an example of such a combination is one in which the particles to be analyzed are Al2O3 particles and the dissolved ions are Al ions.

[0027] The solvent (dispersion medium) of the sample solution may be any solvent as long as it does not impair the objectives of the present disclosure, and may be appropriately selected taking into consideration the type and size of the particles to be analyzed, etc. Typical examples include water; alcohols such as methanol, ethanol, and propanol; and water-alcohol mixtures.

[0028] The particle refinement device and the analysis apparatus in the particle analysis system of the present disclosure will be described below.

[0029] <Particle Purification Device> The particle purification device of the present disclosure is a device that extracts and removes dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane.

[0030] The particle purification device constituting the particle analysis system of the present disclosure is used as a pretreatment device for a sample solution to be introduced into the analysis device in the particle analysis system of the present disclosure, but can also be used for other purposes, such as removing dissolved ions from a solution in which target metal particles and dissolved ions derived from their precursors coexist, thereby purifying the metal particles.

[0031] The ion-permeable membrane used in the particle purification device of the present disclosure may be any membrane that is impermeable to particles contained in the sample solution and selectively permeable to the dissolved ions to be removed, and may be selected appropriately depending on the type and size of the particles to be purified (analyzed), the type of dissolved ions to be removed, etc.

[0032] The ion-permeable membrane may be a microporous membrane or a non-porous membrane as long as it selectively passes dissolved ions to be removed, but typically a microporous membrane that has excellent permeability to the dissolved ions to be removed is used. When the ion-permeable membrane is a microporous membrane, the material and pore size of the microporous membrane need only be such that the particles to be analyzed contained in the sample solution do not pass through, and are appropriately selected in consideration of the type, particle size and concentration of the particles to be analyzed, the type and concentration of the dissolved ions, the type of solvent (dispersion medium), etc.

[0033] Examples of microporous membranes that can be used include known ultrafiltration membranes (pore size: about 10 to 100 nm), nanofiltration membranes (pore size: 2 to 10 nm), and reverse osmosis membranes (pore size: less than 2 nm).

[0034] The material of the microporous membrane is not limited as long as it does not impair the objectives of the present disclosure, but typically a resin (particularly a thermoplastic resin) is used. Specific examples of the resin constituting the microporous membrane include polyolefin, polystyrene, polysulfone, polyethersulfone, polyarylsulfone, polytetrafluoroethylene, fluororesins including polyvinylidene fluoride, and copolymers of these materials.

[0035] When the ion-permeable membrane is a microporous membrane, particles of the analysis target (target of purification) may be adsorbed to the pores of the microporous membrane, which may result in changes in the particle concentration and particle size distribution in the sample solution, making it impossible to perform an accurate analysis. Therefore, a microporous membrane that does not or hardly adsorbs particles of the analysis target can be selected as the ion-permeable membrane, and it is recommended to select a microporous membrane appropriate for the type and particle size (particle size distribution) of particles of the analysis target.

[0036] For example, when the analysis target is a hydrophilic particle (e.g., a metal oxide, etc.), a microporous membrane containing a hydrophobic resin (hydrophobic microporous membrane) can be used as the ion-permeable membrane (microporous membrane). Examples of hydrophobic resins include fluororesins, and examples of fluororesins include polytetrafluoroethylene (PTFE). That is, examples of hydrophobic microporous membranes include microporous membranes containing PTFE.

[0037] Commercially available hydrophobic microporous membranes include, for example, the "Poreflon (registered trademark) Membrane" series (PTFE resin) manufactured by Sumitomo Electric Fine Polymer, Inc.

[0038] Furthermore, when the object of analysis is a hydrophobic particle (e.g., a carbon material, a metal carbide, etc.), a microporous membrane containing a hydrophilic resin (hydrophilic microporous membrane) can be used as the ion-permeable membrane (microporous membrane). Examples of hydrophilic resins include cellulose and nylon. That is, examples of hydrophilic microporous membranes include microporous membranes containing cellulose or nylon. Note that cellulose here also includes natural cellulose, regenerated cellulose, and semi-synthetic cellulose obtained by modifying pure cellulose such as cellulose acetate.

[0039] Examples of commercially available hydrophilic microporous membranes include "Standard RC" (cellulose) manufactured by Repligen and "Membrane Filter" (nylon) manufactured by GVS.

[0040] The particle purification device of the present disclosure can have any configuration as long as it can extract and remove dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane.

[0041] One aspect of the particle purification device of the present disclosure is a particle purification device having a sample solution flow path through which a sample solution containing particles and dissolved ions flows, at least one extract flow path through which an extract flows, and at least one ion-permeable membrane, wherein the sample solution flow path and the extract flow path are positioned opposite each other via the ion-permeable membrane (corresponding embodiments will be described later (FIGS. 1A and 1B)).

[0042] In this specification, the "sample solution," "extract," and "feed liquid" constituting one embodiment of the particle purification device may be referred to as the "first solution," "second solution," and "third solution," respectively. The sample solution flow path, extract flow path, and feed liquid supply flow path may be referred to as the "first flow path," "second flow path," and "third flow path," respectively. The "ion-permeable membrane" and "electrode diaphragm" may be referred to as the "first membrane" and "second membrane," respectively.

[0043] This particle purification device can also be described as having a first flow path through which a first solution containing particles and dissolved ions flows, at least one second flow path through which an extractant, a second solution, flows, and at least one first membrane, in which the first flow path and the second flow path are positioned opposite each other via the first membrane.

[0044] In a particle purification device configured as described above, dissolved ions contained in a sample solution (first solution) flowing through a sample solution flow path (first flow path) permeate the ion-permeable membrane (first membrane) due to an ion concentration gradient formed through the ion-permeable membrane (first membrane) and migrate to an extract (second solution) flowing through an extract flow path (second flow path). In the particle purification device, the dissolved ions are removed from the sample solution by moving them to the extract, thereby obtaining a purified sample solution (purified particle-containing solution). When this purified sample solution is analyzed by an analyzer, the signal derived from the dissolved ions is reduced, allowing the analyzer to analyze particles in the sample solution with high accuracy. Corresponding embodiments will be described later ( FIGS. 6A and 6B ).

[0045] In another aspect, the particle purification device further comprises a pair of electrodes and a power source that generates a predetermined potential difference between the pair of electrodes, the pair of electrodes being positioned opposite each other and sandwiching the sample solution flow path and the extract flow path.

[0046] In another embodiment, an electrode diaphragm may be provided on the front surface of each of the pair of electrodes. The electrode diaphragm may be an ion exchange membrane or a bipolar membrane. The particle purification device of this embodiment includes: a plurality of third flow paths (feed liquid supply flow paths) through which a third solution (feed liquid) flows; a plurality of second membranes (electrode diaphragms) positioned in contact with and between the second flow path (extract flow path) and the third flow path (feed liquid supply flow path); and a plurality of electrodes positioned in contact with the third flow path (feed liquid supply flow path) and on the opposite side of the second membranes (electrode diaphragms), wherein the second membranes (electrode diaphragms), the third flow path (feed liquid supply flow path), and the electrodes are positioned opposite each other across the first flow path (sample solution flow path).

[0047] With this configuration, by generating a predetermined potential difference between the pair of electrodes, the potential gradient formed between the two electrodes facilitates the migration of dissolved ions in the sample solution flowing through the sample solution flow path through the ion permeable membrane into the extract flowing through the extract flow path, thereby improving the removal rate of dissolved ions from the sample solution (ion removal rate). Furthermore, by providing an electrode diaphragm in front of the electrodes, it is possible to prevent gases caused by electrolysis from entering the extract flow path and / or the sample solution flow path.

[0048] The power source for the particle purification device may be any power source as long as it does not impair the objectives of the present disclosure, but for example, a DC power source can be used. In particular, if the DC power source and pulse generating power source are used, the ion permeable membrane can be cleaned by applying a pulse voltage.

[0049] The analyzer in the particle analysis system of the present disclosure is used to analyze the physical properties (particle size, composition, concentration, etc.) of particles contained in a sample solution, and can be used appropriately depending on the physical properties to be evaluated. Examples of the analyzer include an atomic absorption spectrometer, an inductively coupled plasma (ICP) optical emission spectrometer, and an inductively coupled plasma mass spectrometer (ICP-MS).

[0050] In the particle analysis system of the present disclosure, an inductively coupled plasma mass spectrometer (ICP-MS) can be used as an analytical device. An ICP-MS device can measure element concentrations in a solution with high sensitivity and can simultaneously analyze multiple elements. Therefore, even when multiple particles composed of different elements are the analysis target, simultaneous, highly accurate analysis is possible. On the other hand, in an ICP-MS device, measurement accuracy may decrease if dissolved ions containing the same element as the particles to be analyzed coexist. However, in the particle analysis system of the present disclosure, the particle purification device removes dissolved ions from the sample solution, resulting in a purified sample solution, enabling highly accurate particle analysis.

[0051] The particle analysis system of the present disclosure can perform single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) by using an inductively coupled plasma mass spectrometry device (ICP-MS device) as the analysis device.

[0052] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the following embodiments and can be implemented with any modifications within the scope of the gist of the present disclosure. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples to facilitate understanding of the invention and do not limit the present disclosure unless otherwise specified. Furthermore, in all drawings, the same components are designated by the same reference numerals and their descriptions are omitted as appropriate.

[0053] 2. First Embodiment of Particle Analysis System Fig. 1A is a conceptual diagram of a particle analysis system 100A according to a first embodiment. Fig. 1B is a conceptual cross-sectional view of a particle purification device 1A used in the particle analysis system 100A.

[0054] In this embodiment, the particles to be analyzed are alumina (Al ２ O ３ ) particles, and Al ions (Al) as the dissolved ions to be removed. ３＋ An example in which a sample solution containing ) is used will be described.

[0055] As shown in FIG. 1A, the particle analysis system 100A mainly comprises a particle purification device 1A, a sample solution supply unit 2 that supplies a sample solution containing particles to be analyzed to the particle purification device 1A, an extractant supply unit 3 that supplies an acceptor solution to the particle purification device 1A, and an analyzer 4 that analyzes particles contained in the sample solution discharged from the particle purification device 1A.

[0056] Dissolved ions contained in a sample solution along with particles to be analyzed are one of the factors that cause a decrease in the S / N ratio in analysis. In the particle analysis system 100A, the particle purification device 1A is used to remove dissolved ions from the sample solution. In the particle purification device 1A, the dissolved ions contained in the sample solution are selectively removed from the sample solution by selectively permeating through an ion-permeable membrane and being extracted into the extract passing through the extract flow path. In this way, the purified sample solution from which the dissolved ions have been removed is supplied to the analysis device 4 located downstream of the sample solution flow path. This enables highly accurate analysis of particles in the sample solution.

[0057] In this embodiment, an inductively coupled plasma mass spectrometer (ICP-MS) is used as the analyzer 4, and the particles can be analyzed by the SP-ICP-MS method. The SP-ICP-MS method will be described later.

[0058] Each component of the particle analysis system 100A will be described in detail below.

[0059] 1B , particle purification device 1A of this embodiment has a structure in which a first flow path structure 17a composed of a first block 18a and a first gasket 19a, an ion-permeable membrane 12a and an ion-permeable membrane 12b, and a second flow path structure 17b composed of a second gasket 19b and a second block 18b are stacked in this order. Particle purification device 1A having such a structure includes sample solution flow path 11 through which a sample solution containing particles flows, and extract solution flow paths 13a and 13b, which are provided on both sides of sample solution flow path 11, separated by ion-permeable membranes 12a and 12b, and through which an extract solution flows. In other words, particle purification device 1A has sample solution flow path 11 through which a particle-containing sample solution flows, extract flow paths 13a and 13b through which an extract flows, and ion-permeable membranes 12a and 12b, with sample solution flow path 11 and extract flow path 13a facing each other via ion-permeable membrane 12a, and sample solution flow path 11 and extract flow path 13b facing each other via ion-permeable membrane 12b. That is, particle purification device 1A is a particle purification device with a laminated flat plate structure including extract flow path 13a, ion-permeable membrane 12a, sample solution flow path 11, ion-permeable membrane 12b, and extract flow path 13b.

[0060] In the particle purification device 1A of this embodiment, ion-permeable membranes 12a and 12b are disposed on both sides of the sample solution flow path 11, but a particle purification device having an ion-permeable membrane disposed on only one side of the sample solution flow path 11 may also be used. In the configuration of the particle purification device 1A, the thickness of each of the sample solution flow path 11 and the extract flow paths 13a and 13b is determined taking into consideration the type and concentration of dissolved ions contained in the sample solution, the flow rates of the sample solution and the extract, and the like. Specifically, the thickness of each flow path is, for example, in the range of 100 to 500 μm.

[0061] In particle purification device 1A, sample solution supplied from sample solution supply unit 2 flows into sample solution flow path 11, and dissolved ions contained in the sample solution are extracted and removed into an extracting liquid. The purified sample solution from which the dissolved ions have been extracted and removed is then sent to analysis device 4. Note that a conventionally used liquid sending pump can be applied to sample solution supply unit 2.

[0062] The extract flow paths 13a, 13b are adjacent to ion-permeable membranes 12a, 12b arranged along the flow path direction. Extract flow paths 13a, 13b are supplied with extract from an extract supply unit 3 and discharged containing dissolved ions extracted and removed from the sample solution. A conventional liquid delivery pump can be used for the extract supply unit 3.

[0063] The alumina (Al ２ O ３ Since the ion-permeable membranes 12a and 12b are made of alumina (Al ２ O ３ ) particles, and Al ions (Al ３＋ An ion-permeable membrane that allows only ions to pass through is selected.

[0064] In this embodiment, PTFE membranes are used as the ion permeable membranes 12a and 12b. The PTFE membrane is a hydrophobic microporous membrane, and as will be described later in the examples, alumina (Al ２ O ３ ) particles are difficult to adsorb to the PTFE membrane. ３＋ ) selectively permeates the ion-permeable membrane and is extracted and removed into the extract in the extract flow path, and alumina (Al ２ O ３ ) The particles remain in the sample solution.

[0065] Next, with reference to FIG. 2, an operation method of the particle refining device 1A will be described.

[0066] A sample solution containing particles to be analyzed is supplied to sample solution flow path 11 at a predetermined flow rate, and an extract is supplied to extract flow paths 13a and 13b at a predetermined flow rate. In addition to the particles to be analyzed, the sample solution flowing through sample solution flow path 11 also contains dissolved ions that reduce the analytical accuracy. The dissolved ions in the sample solution permeate ion permeable membranes 12a and 12b due to an ion concentration gradient formed via ion permeable membranes 12a and 12b, and move into the extract flowing through extract flow paths 13a and 13b.

[0067] On the other hand, the particles to be analyzed cannot pass through the ion-permeable membrane and remain in the sample solution. As a result, dissolved ions that reduce the accuracy of particle analysis are extracted and removed from the sample solution, and the sample solution containing the particles to be analyzed is sent to the analyzer 4. This allows for accurate particle analysis.

[0068] The particle analysis system 100A includes an analysis device 4 that analyzes particles contained in a sample solution discharged from the sample solution flow path 11 of the particle purification device 1A. The analysis device 4 according to this embodiment is an ICP-MS (inductively coupled plasma mass spectrometry) device, and is capable of performing particle analysis by the SP-ICP-MS method (single particle inductively coupled plasma mass spectrometry).

[0069] The influence of dissolved ions contained in a sample solution in the SP-ICP-MS method will be described with reference to the figures: Fig. 3 is an explanatory diagram of a signal obtained when particles are detected in ICP-MS measurement, Fig. 4 is an explanatory diagram of a signal obtained when dissolved ions are detected in ICP-MS measurement, and Fig. 5 is an explanatory diagram of a signal obtained when particles and dissolved ions are detected in ICP-MS measurement.

[0070] In the SP-ICP-MS method, when the analysis target is particles, ion clusters are generated by the plasma, and the ion clusters are measured as peak signals (peak-shaped signals) by a mass spectrometer. The size of the ion clusters generated from particles varies depending on the particle size. As shown in Figure 3, the signal intensity (peak height) of the peak signal measured by the mass spectrometer is obtained depending on the size of the ion clusters generated from the particles. Furthermore, since particles are intermittently introduced into the ICP-MS device, the peak signals derived from the particles are also measured intermittently. Information about particle size can be obtained from the signal intensity (peak height) of the peak signal, and information about the number of particles can be obtained from the number of peak signals (peak number). The particle size distribution of the particles can be obtained from the obtained information about particle size and number.

[0071] When ions of the particles (metals) to be analyzed are contained in the sample solution as dissolved ions, the signal derived from the dissolved ions is detected as background (noise). As a result, the signal intensity of the signal derived from the dissolved ions (background) increases, as shown in Figure 4.

[0072] Furthermore, as the concentration of dissolved ions in the sample solution increases, the signal intensity of the signal derived from the dissolved ions increases, and the peak signal derived from the particles is buried in the signal derived from the dissolved ions (background). In particular, in the case of particles with small particle sizes, as shown in Figure 5, the peak signal derived from the particles is buried in the signal derived from the dissolved ions (background), making it impossible to distinguish the peak signal derived from the particles. In other words, the presence of dissolved ions reduces the accuracy of particle size analysis.

[0073] In the particle analysis system 100A of this embodiment, the use of a particle purification device makes it possible to extract and remove dissolved ions in a sample solution, so that peak signals derived from particles with small particle sizes can be distinguished without being buried in signals (background) derived from dissolved ions, thereby improving the accuracy of particle measurement in the analysis apparatus 4 (ICP-MS apparatus).

[0074] 3. Second Embodiment of Particle Analysis System A particle analysis system according to a second embodiment will be described with reference to the drawings. In the second embodiment, components having the same configuration as those in the first embodiment will be assigned the same reference numerals, and descriptions thereof may be omitted.

[0075] Fig. 6A is a conceptual diagram of a particle analysis system 100B according to a second embodiment. The particle analysis system 100B is a particle analysis system that uses a particle purification device 1B instead of the particle purification device 1A in the particle analysis system 100A described above. Fig. 6B shows a conceptual cross-sectional view of the particle purification device 1B used in the particle analysis system 100B.

[0076] As shown in the cross-sectional schematic diagram of FIG. 1B, the particle purification device 1B of this embodiment has a structure in which a first flow path structure 17a composed of a first block 18a and a first gasket 19a, an ion-permeable membrane 12a and an ion-permeable membrane 12b, and a second flow path structure 17b composed of a second gasket 19b and a second block 18b are stacked in this order. 6B , the particle purification device 1B includes a sample solution flow path 11 through which a sample solution containing particles flows, extract flow paths 13a and 13b that are provided on both sides of the sample solution flow path 11 with ion-permeable membranes 12a and 12b between them and through which an extract flows, a pair of electrodes 14a and 14b that sandwich the sample solution flow path 11 and the extract flow paths 13a and 13b, electrode diaphragms 15a and 15b that are provided in front of the pair of electrodes 14a and 14b, respectively, and feed liquid supply flow paths 16a and 16b that are provided between the electrodes 14a and 14b and the electrode diaphragms 15a and 15b, and a power source 5 that generates a predetermined potential difference between the electrodes 14a and 14b. Note that the power source 5 in this embodiment is a DC power source, but it may also include a pulse-generating power source. In other words, particle purification device 1B has sample solution flow path 11 through which a sample solution containing particles flows, extract flow paths 13a, 13b through which an extract flows, and ion-permeable membranes 12a, 12b, with sample solution flow path 11 and extract flow paths 13a, 13b positioned opposite each other via ion-permeable membranes 12a, 12b, and further has feed liquid supply flow paths 16a, 16b through which a feed liquid flows, electrode diaphragms 15a, 15b positioned between and in contact with the extract flow paths 13a, 13b and the feed liquid supply flow paths 16a, 16b, and electrodes 14a, 14b positioned opposite electrode diaphragms 15a, 15b and in contact with the feed liquid supply flow paths 16a, 16b, with sample solution flow path 11 interposed between electrode diaphragms 15a, 15b, and electrodes 14a, 14b.

[0077] That is, particle purification device 1B differs from the above-described particle purification device 1A in that a first flow path structure 17a has an electrode 14a, an electrode diaphragm 15a, and a feed liquid supply flow path 16a, and a second flow path structure 17b has an electrode 14b, an electrode diaphragm 15b, and a feed liquid supply flow path 16b, and in that it has a power source 5.

[0078] 7, particle purification device 1B has the above-described configuration, and as a driving force acting on dissolved ions contained in the sample solution, a potential gradient is superimposed on the above-described ion concentration gradient, causing anions to move to extract flow path 13a on the positive electrode 14a side and cations to move to extract flow path 13b on the negative electrode 14b side. As a result, dissolved ions can be extracted and removed from sample solution flow path 11 more efficiently.

[0079] Furthermore, although the particle purification device 1B has electrode diaphragms 15a and 15b provided on the front surfaces of the pair of electrodes 14a and 14b, the electrode diaphragms 15a and 15b may not be provided as long as they do not affect particle analysis.

[0080] In particle purification device 1B, a voltage is applied between the electrodes to promote the extraction and removal of dissolved ions, which can reduce the accuracy of particle analysis. However, if the applied voltage exceeds the electrolysis voltage of the solvent, water, oxygen is generated at the positive electrode and hydrogen is generated at the negative electrode due to the electrolysis of water. If these gases are mixed into the sample solution and introduced into a downstream analytical device along with the sample solution, this could reduce the analytical accuracy and cause equipment problems. To prevent gases resulting from the electrolysis from mixing into the sample solution, particle purification device 1B can be provided with an electrode diaphragm on the front surface of each of the pair of electrodes.

[0081] In the particle purification device 1B according to this embodiment, the electrode 14a is a positive electrode, the electrode 14b is a negative electrode, the electrode diaphragm 15a is a cation exchange membrane, and the electrode diaphragm 15b is an anion exchange membrane. The feed liquid supply flow path 16a (16b) is a flow path between the electrode 14a (14b) and the electrode diaphragm 15a (15b). By passing the feed liquid through this flow path, H generated by electrolysis due to application of a voltage between the electrodes 14a and 14b is circulated. + , O.H. - , hydrogen gas, and oxygen gas can be flushed out to clean the surface.

[0082] Although the embodiments of the present disclosure have been described above with reference to the drawings, the embodiments disclosed herein are illustrative in all respects and are not limiting. In particular, matters not expressly disclosed in the embodiments disclosed herein, such as operating conditions, various parameters, dimensions, weights, volumes, etc., do not deviate from the scope of ordinary practice by a person skilled in the art, and values ​​that can be easily assumed by a person skilled in the art can be used.

[0083] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0084] 1. Calculation of the Lower Detection Limit of Particles and Evaluation of the Recovery Rate of Particles In the examples of the particle analysis system of the present disclosure, the calculation of the lower detection limit of particles and the recovery rate of particles when using a particle purification device were evaluated.

[0085] [1-1. Particle Analysis System] Particles contained in a sample solution were analyzed using a particle analysis system 100B and particle purification device 1B configured as shown in Figures 6A and 6B. The particle purification device 1B in the particle analysis system 100B actually used was configured as follows. Note that a constant-volume pump (MP-2000, Tokyo Rikakikai Co., Ltd.) was used for the sample solution supply unit 2 and the extract supply unit 3, and an ICP-MS device (Agilent 8900 ICP-QQQ-MS, manufactured by Agilent) was used for the analysis device 4.

[0086] [Particle purification device (5 channels)] Electrode 14a (positive electrode): platinum-plated mesh Ion permeable membranes 12a, 12b: PTFE membrane (manufactured by Sumitomo Electric Fine Polymer Co., Ltd., trade name: Poiflon Membrane (HP-010-30), pore size 0.1 μm, membrane thickness 30 μm) Cellulose membrane (manufactured by Repligen, trade name: Standard RC tubing, molecular weight cutoff 6 to 7 kD, membrane thickness 77 μm) Nylon membrane (manufactured by GVS, trade name: Membrane Filter, pore size 1.2 μm, membrane thickness 126 μm) Electrode diaphragm 15a: cation exchange membrane (manufactured by AGC Engineering Co., Ltd., Selemion (registered trademark) CMV, thickness 130 μm) Electrode diaphragm 15b: anion exchange membrane (manufactured by AGC Engineering Co., Ltd., Selemion (registered trademark) AMV, thickness 130 μm) Electrode 14b (negative electrode): platinum-plated mesh The dimensions of the sample solution flow path 11, extract flow paths 13a and 13b, and feed solution supply flow paths 16a and 16b of the particle purification device 1B configured as described above are as follows: Sample solution flow path 11: width 5 mm, length 40 mm, thickness 127 μm Extract solution flow paths 13a and 13b: width 5 mm, length 40 mm, thickness 127 μm Feed solution supply flow paths 16a and 16b: width 5 mm, length 40 mm, thickness 127 μm

[0087] [1-2. Experimental Example 1 (Al ２ O ３ Preparation of Al particle dispersion solution ２ O ３ Powder (manufactured by Iolitec, Aluminum oxide (α-form) 80 nm) was transferred to a polypropylene container, ultrapure water (resistivity 18 MΩ cm or more) was added, and ultrasonic waves were irradiated for 10 minutes. This solution was diluted with ultrapure water to a particle concentration of 3 μg / L to prepare the solution of Experimental Example 1, which served as the evaluation standard.

[0088] [1-3. Preparation of Solutions of Experimental Example 2 (Cellulose Membrane) and Experimental Example 3 (PTFE Membrane) Using a Particle Purification Device] Solutions of Experimental Examples 2 and 3 (purified particle-containing solutions) were prepared using a particle purification device having a configuration similar to that of particle purification device 1B in FIG. 6B.

[0089] Unrefined Al ２ O ３The particle dispersion solution of Experimental Example 1 was introduced into particle purification devices with different ion-permeable membranes (cellulose membrane, PTFE membrane), and 3 mL of the solution emerging from the sample solution outlet of the particle purification device was recovered. The recovered solution when the ion-permeable membrane was a cellulose membrane was the solution of Experimental Example 2, and the recovered solution when the ion-permeable membrane was a PTFE membrane was the solution of Experimental Example 3. The particle purification device treatment conditions for the solutions of Experimental Examples 2 and 3 are as follows: Sample solution (Experimental Example 1) flow rate: 1.0 mL / min Sample solution (Experimental Example 1): Al ２ O ３ Particle 80nm dispersion liquid / Extract liquid: 10mM HNO ３ 1.0 mL / min Feed solution: 10 mM HNO ３ 0.5 mL / min Particle purification processing voltage: 0 V

[0090] [1-4. SP-ICP-MS Measurement] Measurements were carried out using the SP-ICP-MS method for Experimental Example 1 (unpurified), Experimental Example 2 (purified), and Experimental Example 3 (purified). The measurement conditions are as follows: Measurement element: Al (m / z 27) Measurement time: 60 s Sampling period: 0.1 ms Cell gas: No gas RF power: 1550 W Analysis mode: 1 element analysis Control software: Single nanoparticle application

[0091] [1-5. Calculation of particle recovery rate] In order to determine whether a signal is derived from particles based on the magnitude of the signal intensity in the signal intensity data obtained by SP-ICP-MS measurement, a particle detection lower limit was set. Peak signals showing a signal intensity equal to or greater than the particle detection lower limit were considered to be signals derived from particles and were counted as the number of detected particles. The particle recovery rate was calculated from the number of detected particles in each solution (Experimental Example 1, Experimental Example 2, Experimental Example 3).

[0092] Specifically, the following steps (A) to (C) were carried out.

[0093] (A) The total number of data points was calculated by dividing the data sampling time of the measured signal intensity data by the data sampling interval. In the measured signal intensity data, peak signals were arranged in ascending order of signal intensity, and the signals were classified into predetermined signal intensity widths (ranges). The number of signals was counted for each signal intensity width (range), starting from the signal classified into the signal intensity width (range) with the highest signal intensity. The number of signals was counted, and when the number of signals (count number) included in a predetermined signal intensity width (range) first reached 0.01% or more of the total number of data points, the highest signal intensity among the signals included in this predetermined signal intensity width (range) was identified. Signals below the identified signal intensity were considered to be signals derived from dissolved ions (ion signals). The signal intensities of all ion signals were statistically processed to determine the particle detection lower limit (I) for identifying signals derived from particles. ＤＬ ) was calculated. Statistical processing was performed using the following formula:

[0094] (X: average value of ion signal intensity, σ: standard deviation of ion signal intensity, σ coefficient is adjusted appropriately)

[0095] (B) In the signal intensity data obtained by SP-ICP-MS measurement, the particle detection limit (I ＤＬ ) were regarded as signals derived from particles, and the number of peak signals in each solution (Experimental Example 1, Experimental Example 2, Experimental Example 3) was counted as the number of detected particles.

[0096] (C) The particle recovery rates of Experimental Examples 2 and 3 were calculated by dividing the number of detected particles in Experimental Examples 2 and 3 by the number of detected particles in Experimental Example 1. The formula for calculating the particle recovery rate is shown below.

[0097] (N ｂｌａｎｋ : Number of detected particles in Experimental Example 1, N ｅｖａｌ : Number of detected particles in Experimental Example 2 or Experimental Example 3)

[0098] [1-6. Lower limit of particle detection] Figure 8 shows the ICP-MS measurement results for Experimental Example 1. As shown in Figure 8, peak signals and background signals were confirmed. The lower limit of particle detection for Experimental Example 1, Experimental Example 2, and Experimental Example 3 was determined according to the procedure described above in [1-5. Calculation of particle recovery rate].

[0099] [1-7. Particle Recovery Rate] The particle recovery rates of Experimental Examples 2 and 3 were calculated. Fig. 9 shows the particle recovery rates of Experimental Example 2 (cellulose membrane) and Experimental Example 3 (PTFE membrane). As shown in Fig. 9, the particle recovery rate of Experimental Example 3, in which a PTFE membrane was used as the ion permeable membrane of the particle purification device, was higher than the particle recovery rate of Experimental Example 2, in which a cellulose membrane was used. This is presumably because the use of a PTFE membrane, which is a hydrophobic porous membrane, as the ion permeable membrane reduced particle adsorption to the ion permeable membrane.

[0100] <2. Particle purification evaluation (Al ２ O ３ Particles and Al ions> Using the particle purification device, an evaluation was carried out to purify particles from a sample solution containing particles and dissolved ions.

[0101] [2-1. Preparation of Solutions Containing Particles and Dissolved Ions for Experimental Example 4 (Unpurified Particles) and Experimental Example 5 (Purified Particles)] An Al ion standard solution (Kanto Chemical, aluminum standard solution (Al 1000) for atomic absorption spectrometry) was added to the solution of Experimental Example 1 so that the Al ion concentration became a predetermined concentration, thereby preparing solutions of Experimental Example 4 (Al ion concentrations: 2.19 μg / L, 6.38 μg / L, and 16.2 μg / L).

[0102] The solution of Experimental Example 4 was introduced into a particle purification device (PTFE membrane), and 3 mL of the solution coming out of the sample solution outlet was recovered to prepare a solution (recovered solution) of Experimental Example 5. The particle purification device treatment conditions for the solution of Experimental Example 5 are as follows: Sample solution (Experimental Example 4) flow rate: 2.0 mL / min Sample solution (Experimental Example 4): Al ２ O ３ 80 nm particle dispersion + Al ions (2.19 μg / L, 6.38 μg / L, 16.2 μg / L) Extraction solution: 10 mM HNO ３ 1.0 mL / min Feed solution: 10 mM HNO ３0.5 mL / min Particle purification processing voltage: 0 V

[0103] [2-2. SP-ICP-MS Measurement] The solutions of Experimental Examples 4 and 5 were measured using the same method as in [1-2. SP-ICP-MS Measurement] above.

[0104] [2-3. Calculation of particle recovery rate] The particle recovery rates of the solutions of Experimental Examples 4 and 5 were calculated using the same method as in [1-3. Particle recovery rate] above.

[0105] Calculation of ion removal rate The ion removal rate was calculated from the average value of the signal intensities of the ion signals in Experimental Examples 1, 4, and 5. The formula for calculating the ion removal rate is shown below.

[0106] (C ｂｌａｎｋ : average value of signal intensity of ion signals in Experimental Example 1, C ４ : average value of signal intensity of ion signals in Experimental Example 4, C ５ : average value of signal intensity of ion signals in Experimental Example 5)

[0107] [2-5. Calculation of particle size detection lower limit] The calculated particle detection lower limit (I ＤＬ ) to the mass of the particle (m ＤＬ ) and calculate the mass of the particle (m ＤＬ ) is converted to particle size (nm) to obtain the particle size detection limit (D ＤＬ The formula for determining the particle size detection limit is shown below.

[0108]

[0109] (I ＤＬ : particle detection limit (cps), s: response coefficient (cps / ppb), t: integration time (s), V: sample flow rate (mL / min), η: spray efficiency, f: molar mass of particle / molar mass of element to be analyzed, ρ: particle density (g / cm ３ ))

[0110] [2-5. Particle Recovery Rate and Ion Removal Rate] Figure 10 shows the SP-ICP-MS measurement results for Experimental Example 4, and Figure 11 shows an enlarged view of the results. Figure 12 shows the SP-ICP-MS measurement results for Experimental Example 5, and Figure 13 shows an enlarged view of the results. As shown in Figures 10 and 11, the ion signal intensity for Experimental Example 4, in which particle purification was not performed using a particle purification device (PTFE membrane), was relatively high. On the other hand, as shown in Figures 12 and 13, the ion signal intensity for Experimental Example 5, in which particle purification was performed using a particle purification device (PTFE membrane), was reduced. The particle recovery rate and ion removal rate were calculated from the SP-ICP-MS measurement results for Experimental Examples 4 and 5, and the particle recovery rate was found to be 96±1.6%, and the ion removal rate was calculated to be 99±0.5%. Both high values ​​were obtained, demonstrating the excellent performance of the particle purification process using the particle purification device (PTFE membrane).

[0111] [2-6. Correlation between Al ion concentration and ion removal rate] The average value of the signal intensity of the ion signal and the ion removal rate were calculated for Experimental Example 4 (before particle purification treatment) and Experimental Example 5 (after particle purification treatment) at each Al ion concentration. Figure 14 shows the correlation between the Al ion concentration, the average value of the signal intensity of the ion signal, and the ion removal rate. As shown in Figure 14, although the ion removal rate decreased as the Al ion concentration increased, an ion removal rate of 90% or more could be maintained when the Al ion concentration was 6 μg / L or less.

[0112] [2-7. Lower limit of particle size detection] The lower limit of particle size detection at each Al ion concentration was determined from the lower limit of particle detection in Experimental Examples 4 and 5. Figure 15 shows the correlation between Al ion concentration and lower limit of particle size detection. As shown in Figure 15, the lower limit of particle size detection increased as the Al ion concentration increased, but the lower limit of particle size detection decreased when ions were removed by particle purification processing using the particle purification device.

[0113] 3. Evaluation of Particle Purification (Ag Particles and Ag Ions) Using the particle purification device described above, an evaluation was performed on the purification of particles from a sample solution containing particles and dissolved ions by applying a voltage. The following ion-permeable membranes were used for the ion-permeable membranes 12a and 12b. PTFE membrane (manufactured by Sumitomo Electric Fine Polymer Co., Ltd., product name: Poiflon Membrane (HP-010-30), pore size 0.1 μm, membrane thickness 30 μm) Cellulose membrane (manufactured by Repligen, product name: Standard RC tubing, molecular weight cutoff 6 to 7 kD, membrane thickness 77 μm) Nylon membrane (manufactured by GVS, product name: Membrane Filter, pore size 1.2 μm, membrane thickness 126 μm)

[0114] [3-1. Preparation of Solution of Experimental Example 6 (Ag Particle Dispersion)] Al ２ O ３ The same procedure as in [1-2. Experimental Example 1 (Al ２ O ３ The solution of Experimental Example 6 was prepared in the same manner as in [Preparation of Solution of Particle Dispersion].

[0115] [3-2. Preparation of Solutions Containing Particles and Dissolved Ions for Experimental Example 7 (Unpurified Particles) and Experimental Examples 8-1 to 8-3 (Particle Purification by Voltage Application)] An Ag ion standard solution (Kanto Chemical, silver standard solution (Ag1000) for atomic absorption spectrometry) was added to Experimental Example 6 so that the Ag ion concentration reached a predetermined concentration (3 μg / L), to prepare the solution of Experimental Example 7. Experimental Example 7 was introduced into a particle purification device (PTFE membrane, cellulose membrane, or nylon membrane), and 3 mL of the solution emerging from the sample solution outlet of the particle purification device was collected to prepare the solutions of Experimental Example 8-1 (PTFE membrane), Experimental Example 8-2 (cellulose membrane), and Experimental Example 8-3 (nylon membrane). The particle purification device treatment conditions for Experimental Example 8 are shown below. Sample solution (Experimental Example 7) flow rate: 2.0 mL / min Sample solution (Experimental Example 7): Ag particle 60 nm dispersion + Ag ions 3 μg / L Extraction solution: 10 mM HNO ３ 1.0 mL / min Feed solution: 10 mM HNO ３0.5 mL / min Particle purification processing voltage: 0 V, 20 V, 35 V

[0116] [3-3. SP-ICP-MS Measurement] Measurements of Experimental Examples 6, 7, and 8-1 to 8-3 were carried out by the same method as in [1-4. SP-ICP-MS Measurement] above.

[0117] [3-4. Calculation of particle recovery rate] The particle recovery rates of Experimental Examples 7 and 8 were calculated using the same method as in [1-5. Calculation of particle recovery rate] above.

[0118] [3-5. Calculation of ion removal rate] The ion removal rate was calculated from the average value of the signal intensity of the ion signals in Experimental Examples 7 and 8 using the same method as in [2-4. Calculation of ion removal rate] above.

[0119] [3-6. Particle recovery rate and ion removal rate] Figure 16 shows the ICP-MS measurement results for Experimental Example 7, and Figure 17 shows the SP-ICP-MS measurement results for Experimental Example 8-1 (PTFE membrane) as a representative example. As shown in Figure 16, the signal intensity of the ion signal for Experimental Example 7, in which particle purification was not performed with a particle purification device, was relatively large, but as shown in Figure 17, the signal intensity of the ion signal for Experimental Example 8-1, in which particle purification was performed with a particle purification device (PTFE membrane), was reduced.

[0120] [3-7. Correlation between Particle Refining Treatment Voltage and Ion Removal Rate] Particle refining treatment was performed by setting the particle refining treatment voltage to 0 V, 20 V, and 35 V. Figure 18 shows the correlation between the particle refining treatment voltage and the ion removal rate. As shown in Figure 18, the ion removal rate improved as the applied particle refining treatment voltage increased.

[0121] [3-8. Correlation between the type of ion-permeable membrane and the particle recovery rate and ion removal rate] Purification treatment of Ag particles (treatment voltage 0 V (no voltage applied)) was carried out using a particle purification device using a PTFE membrane, a cellulose membrane, or a nylon membrane as the ion-permeable membrane. Table 1 shows the results of particle recovery rate and ion removal rate.

[0122]

[0123] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0124] The present disclosure includes particle analysis systems of the following aspects: <1> A particle analysis system comprising: a particle purification device that extracts and removes dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane; and an analyzer that analyzes the particles contained in the sample solution from which the dissolved ions have been removed by the particle purification device. <2> The particle purification device comprises a sample solution flow path through which the sample solution flows, at least one extract flow path through which an extract flows, and at least one ion-permeable membrane, the sample solution flow path and the extract flow path being positioned opposite each other via the ion-permeable membrane, the particle analysis system comprising: a sample solution supply unit that supplies the sample solution containing the particles and the dissolved ions to the sample solution flow path of the particle purification device; an extract supply unit that supplies the extract to the extract flow path of the particle purification device; and an analyzer that analyzes the particles contained in the sample solution discharged from the sample solution flow path of the particle purification device. <3> The particle analysis system according to <2>, wherein the particle purification device further comprises a pair of electrodes and a power supply for generating a predetermined potential difference between the pair of electrodes, the pair of electrodes being positioned opposite each other and sandwiching the sample solution flow path and the extract flow path. <4> The particle analysis system according to <3>, wherein the power supply is a DC power supply and a pulse-generating power supply. <5> The particle analysis system according to any one of <1> to <4>, wherein the ion-permeable membrane in the particle purification device is a hydrophobic microporous membrane. <6> The particle analysis system according to <5>, wherein the hydrophobic microporous membrane is a microporous membrane containing polytetrafluoroethylene (PTFE) resin. <7> The particle analysis system according to any one of <1> to <4>, wherein the ion-permeable membrane in the particle purification device is a hydrophilic microporous membrane. <8> The particle analysis system according to <7>, wherein the hydrophilic microporous membrane is a microporous membrane containing cellulose or nylon. <9> The particle analysis system according to any one of <1> to <8>, wherein the analysis device is an inductively coupled plasma mass spectrometer (ICP-MS device). <10> The particle analysis system according to any one of <1> to <9>, wherein the particles to be analyzed are particles containing a metal or a metal compound.<11> The particle analysis system according to <10>, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles. <12> The particle analysis system according to any one of <1> to <11>, wherein the size of the particles to be analyzed is 2 nm or more and 500 nm or less.

[0125] The present disclosure includes the following particle analysis methods. <1a> A particle analysis method using a particle purification device equipped with an ion-permeable membrane to remove dissolved ions from a sample solution containing particles and dissolved ions, and analyzing the solution with an analytical instrument. <2a> The particle analysis method according to <1a>, wherein the particle purification device has a sample solution flow path through which the sample solution flows, at least one extract flow path through which an extract flows, and at least one ion-permeable membrane, the sample solution flow path and the extract flow path being positioned opposite each other via the ion-permeable membrane, and the dissolved ions contained in the sample solution are extracted and removed into the extract via the ion-permeable membrane. <3a> The particle analysis method according to <1a> or <2a>, wherein the analytical instrument is an inductively coupled plasma mass spectrometer (ICP-MS instrument). <4a> The particle analysis method according to any one of <1a> to <3a>, wherein the particles to be analyzed are particles containing a metal or a metal compound. <5a> The method for analyzing particles according to <4a>, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles. <6a> The method for analyzing particles according to any one of <1a> to <6a>, wherein the size of the particles to be analyzed is 2 nm or more and 500 nm or less.

[0126] The present disclosure includes the following particle purification devices and methods for producing purified particle-containing solutions. <1b> A particle purification device comprising: a sample solution flow path through which a sample solution containing particles and dissolved ions flows; at least one extract flow path through which an extract flows; and at least one ion-permeable membrane, wherein the sample solution flow path and the extract flow path are positioned opposite each other via the ion-permeable membrane, and wherein the dissolved ions contained in the sample solution are extracted and removed into the extract. <2b> The particle purification device according to <1b>, further comprising a pair of electrodes and a power supply for generating a predetermined potential difference between the pair of electrodes, the pair of electrodes being positioned opposite each other and sandwiching the sample solution flow path and the extract flow path. <3b> The particle purification device according to <2b>, wherein the power supply is a DC power supply and a pulse-generating power supply. <4b> The particle purification device according to any one of <1b> to <3b>, wherein the ion-permeable membrane in the particle purification device is a hydrophobic microporous membrane. <5b> The particle purification device according to <4b>, wherein the hydrophobic microporous membrane is a microporous membrane containing polytetrafluoroethylene (PTFE) resin. <6b> The particle purification device according to any one of <1b> to <3b>, wherein the ion-permeable membrane in the particle purification device is a hydrophilic microporous membrane. <7b> The particle purification device according to <6b>, wherein the hydrophilic microporous membrane is a microporous membrane containing cellulose or nylon. <8b> The particle purification device according to any one of <1b> to <7b>, wherein the particles to be purified are particles containing a metal or a metal compound. <9b> The particle purification device according to <8b>, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles. <10b> The particle purification device according to any one of <1b> to <9b>, wherein the size of the particles to be purified is 2 nm or more and 500 nm or less. <11b> A method for producing a purified particle-containing solution, comprising: passing a sample solution containing the particles to be purified and the dissolved ions through the sample solution flow path of a particle purification device described in any one of <1b> to <10b>; while passing an extract through the extract flow path, thereby transferring the dissolved ions into the extract in the extract flow path and removing the dissolved ions from the sample solution.<12b> The method for producing a purified particle-containing solution according to <11b>, which is a pretreatment for single particle inductively coupled plasma mass spectrometry (SP-ICP-MS).

[0127] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0128] DESCRIPTION OF SYMBOLS 1A, 1B Particle purification device 2 Sample solution supply section 3 Extraction liquid supply section 4 Analysis apparatus 5 Power supply 11 Sample solution flow path (first flow path) 12a, 12b Ion permeable membrane (first membrane) 13a, 13b Extraction liquid flow path (second flow path) 14a, 14b Electrode 15a, 15b Electrode diaphragm (second membrane) 16a, 16b Feed liquid supply flow path (third flow path) 17a, 17b Flow path structure 18a, 18b Block 19a, 19b Gasket 100A, 100B Particle analysis system W Electric wire

Claims

1. A particle analysis system comprising: a particle purification device that extracts and removes dissolved ions from a sample solution containing particles and dissolved ions by passing the dissolved ions through an ion-permeable membrane; and an analysis apparatus that analyzes the particles contained in the sample solution from which the dissolved ions have been removed by the particle purification device.

2. The particle purification device according to claim 1, wherein the particle purification device has a sample solution flow path through which the sample solution flows, at least one extraction liquid flow path through which an extract liquid flows, and at least one ion-permeable membrane, the sample solution flow path and the extraction liquid flow path being positioned opposite each other via the ion-permeable membrane, and the particle analysis system according to claim 1 further comprises: a sample solution supply unit that supplies the sample solution containing the particles and the dissolved ions to the sample solution flow path of the particle purification device; an extraction liquid supply unit that supplies the extraction liquid to the extraction liquid flow path of the particle purification device; and an analysis apparatus that analyzes the particles contained in the sample solution discharged from the sample solution flow path of the particle purification device.

3. The particle analysis system of claim 2, wherein the particle purification device further comprises a pair of electrodes and a power source that generates a predetermined potential difference between the pair of electrodes, the pair of electrodes being positioned opposite each other and sandwiching the sample solution flow path and the extraction liquid flow path.

4. A particle analysis system according to claim 3, wherein said power source is a DC power source and a pulse generating power source.

5. A particle analysis system according to any one of claims 1 to 4, wherein the ion-permeable membrane in the particle purification device is a hydrophobic microporous membrane.

6. The particle analysis system according to claim 5, wherein the hydrophobic microporous membrane is a microporous membrane containing polytetrafluoroethylene (PTFE) resin.

7. A particle analysis system according to any one of claims 1 to 4, wherein the ion-permeable membrane in the particle purification device is a hydrophilic microporous membrane.

8. The particle analysis system according to claim 7, wherein the hydrophilic microporous membrane is a microporous membrane comprising cellulose or nylon.

9. A particle analysis system according to any one of claims 1 to 8, wherein the analysis device is an inductively coupled plasma mass spectrometer (ICP-MS device).

10. A particle analysis system according to any one of claims 1 to 9, wherein the particles to be analyzed are particles containing a metal or a metal compound.

11. A particle analysis system according to claim 10, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles.

12. A particle analysis system according to any one of claims 1 to 11, wherein the size of the particles to be analyzed is 2 nm or more and 500 nm or less.

13. A method for analyzing particles, comprising using a particle purification device equipped with an ion-permeable membrane to remove dissolved ions from a sample solution containing particles and the dissolved ions, and then analyzing the solution with an analytical instrument.

14. A method for analyzing particles as described in claim 13, wherein the particle purification device has a sample solution flow path through which the sample solution flows, at least one extract solution flow path through which an extract solution flows, and at least one ion-permeable membrane, the sample solution flow path and the extract solution flow path being positioned opposite each other via the ion-permeable membrane, and the dissolved ions contained in the sample solution are extracted and removed into the extract solution via the ion-permeable membrane.

15. The method for analyzing particles according to claim 13 or 14, wherein the analytical instrument is an inductively coupled plasma mass spectrometer (ICP-MS instrument).

16. A method for analyzing particles according to any one of claims 13 to 15, wherein the particles to be analyzed are particles containing a metal or a metal compound.

17. The method for analyzing particles according to claim 16, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles.

18. A particle purification device comprising a sample solution flow path through which a sample solution containing particles and dissolved ions flows, at least one extraction liquid flow path through which an extraction liquid flows, and at least one ion-permeable membrane, wherein the sample solution flow path and the extraction liquid flow path are positioned opposite each other via the ion-permeable membrane, and which extracts and removes the dissolved ions contained in the sample solution into the extraction liquid.

19. A particle purification device as described in claim 18, further comprising a pair of electrodes and a power source for generating a predetermined potential difference between the pair of electrodes, the pair of electrodes being positioned opposite each other and sandwiching the sample solution flow path and the extract flow path.

20. The particle purification device of claim 19, wherein the power source is a DC power source and a pulse generating power source.

21. The particle purification device according to any one of claims 18 to 20, wherein the ion-permeable membrane in the particle purification device is a hydrophobic microporous membrane.

22. The particle purification device according to claim 21, wherein the hydrophobic microporous membrane is a microporous membrane containing polytetrafluoroethylene (PTFE) resin.

23. The particle purification device according to any one of claims 18 to 20, wherein the ion-permeable membrane in the particle purification device is a hydrophilic microporous membrane.

24. The particle purification device of claim 23, wherein the hydrophilic microporous membrane is a microporous membrane comprising cellulose or nylon.

25. A particle purification device according to any one of claims 18 to 24, wherein the particles to be purified are particles containing a metal or a metal compound.

26. The particle purification device according to claim 25, wherein the dissolved ions to be removed are dissolved ions containing the same metal element as the particles.

27. A particle purification device according to any one of claims 18 to 26, wherein the size of the particles to be purified is 2 nm or more and 500 nm or less.

28. A method for producing a purified particle-containing solution, comprising flowing a sample solution containing the particles to be purified and the dissolved ions through the sample solution flow path of a particle purification device described in any one of claims 18 to 27, while flowing the extract through the extract flow path, thereby moving the dissolved ions into the extract in the extract flow path and removing the dissolved ions from the sample solution.

29. The method for producing a purified particle-containing solution according to claim 28, which is a pretreatment for single particle inductively coupled plasma mass spectrometry (SP-ICP-MS).

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