JP7045990B2 - Physical structure evaluation method - Google Patents

Description

The present invention relates to an analytical method. More specifically, the present invention evaluates the difference in the physical structure of the entire sample at low cost and quickly with high sensitivity for each component regardless of the number of components and the layer structure of the sample, and multiple factors are used. Regarding analysis methods that can be evaluated collectively.

In the field of organic electronics, organic films are mainly produced by a vapor deposition method. However, increasing the area and reducing the cost of devices are indispensable issues for the development of industry, and the development of processes by the coating method is becoming active as a means to solve them. It is known that the film quality of organic films has a great influence on device characteristics. The major problem is that the film quality of the organic film produced by the coating method is inferior to that produced by the vapor deposition method. Therefore, it is necessary to optimize the organic materials constituting the organic film, the process method, the process conditions, and the like.

Therefore, there is a need for a method for evaluating the difference in film quality between the film (deposited film) obtained by the vapor deposition method and the film (coating film) obtained by the coating method, or the difference between coating films having different production conditions. ing. In particular, the organic film is composed of a plurality of components and often has a multi-layer structure, and evaluation for each component is required. There are various factors in the film quality such as film density, orientation of substances constituting the film, crystallinity, cohesiveness and amorphousness, film hardness, film surface roughness, and film thickness. Therefore, various methods such as microscopic observation (optical microscope, SEM, TEM, AFM and SPM, etc.) and spectroscopic analysis (XRR, spectroscopic ellipsometry, Raman spectroscopy, FTIR, SAXS, WAXS and XRD) are used for film quality evaluation. Has been done.

For example, Non-Patent Document 1 describes molecular orientation evaluation by spectroscopic ellipsometry. Further, Non-Patent Documents 2 and 3 describe analysis of a thin film structure or the like using X-ray scattering or the like.

On the other hand, in the field of organic electronics, analysis using TOFMS, which can extract data for each chemical component, is also performed. Non-Patent Document 4 describes a technique for evaluating chemical deterioration in an organic light emitting diode by LDI-TOFMS. Non-Patent Document 5 describes a technique in which an organic film sample having a multi-layer structure is separated for each layer by LDI-TOFMS and the distribution of the constituent chemical components in the depth direction of the film is evaluated.

Daisuke Yokoyama, Journal of Organic Molecules and Bioelectronics Subcommittee Vol.22, No.4 (November 2011) 203-208 G. Gupta et al., Appl.Mater.Interfaces 2015, 7, 12309-12318 Yuko Kojima, SPring-8 Utilization Promotion Council Green Energy Study Group, "Nanostructure Analysis of Thin Films for Applied Organic Solar Cells", November 5, 2012, [online], [Search on April 13, 2016], Internet <http://www.spring8.or.jp/ext/ja/iuss/htm/text/12file/green_energy/7th/2.kojima.pdf> I.R. de Moraes et. Al., Organic Electronics 13 (2012) 1900-1907 Takaya Sato et al., "Study of Depth Direction Analysis of Organic Thin Films by Laser Desorption and Ionization", Abstracts of Mass Spectrometry General Discussion Vol. 62, Page. 131 (2014.05.07)

However, the prior art as described above has room for improvement in that it provides an analytical method capable of evaluating differences in the physical structure of a sample with high sensitivity at low cost or quickly, and evaluating a plurality of factors. rice field. Further, when the sample is composed of a plurality of components or has a multi-layer structure, analysis is often difficult.

For example, the techniques described in Non-Patent Documents 1 to 3 have been used to measure a limited number of factors. Therefore, when measuring a plurality of factors, it is necessary to combine a plurality of measurement methods, which poses a problem of cost and time for evaluation. The technique described in Non-Patent Document 1 calculates and evaluates the optical characteristics of the entire sample in principle by calculating the physical constants of the sample itself and the fitting parameters optimized by using a theoretically constructed formula. ing. Therefore, in the technique described in Non-Patent Document 1, when the sample is composed of a plurality of components or has a multi-layer structure, it is difficult to evaluate the separation of each component or each layer.

Further, in the conventional technique, it may be difficult to evaluate the physical structure of the sample from the viewpoint of sensitivity. The technique described in Non-Patent Document 1 is difficult to properly evaluate in a thin film sample of 100 nm or less as used in organic electronics because the fitting accuracy is lowered in principle.

Further, the techniques of Non-Patent Documents 2 and 3 using synchrotron radiation X-rays have high evaluation sensitivity, but are expensive in themselves and are used in a specific facility, so that the evaluation frequency is limited. In addition, when the sample is composed of a plurality of components or has a multi-layer structure, it is difficult to evaluate the separation of each component or each layer in principle, and the penetration depth of X-rays into the sample is limited. Therefore, it may not be possible to evaluate the entire sample. In particular, the GI-SAXS method or the GI-WAXS method used to improve the sensitivity is limited to the evaluation of only the sample surface.

The technique described in Non-Patent Document 4 evaluates chemical changes, not the physical structure of an organic film.

One aspect of the present invention has been made in view of the above-mentioned problems, and an object thereof is to quickly and inexpensively change the physical structure of the entire sample regardless of the number of constituent components and the layer structure of the sample. The purpose is to realize an analysis method capable of evaluating each component with high sensitivity and collectively evaluating a plurality of factors.

As a result of diligent studies to solve the above problems, the present inventors evaluated the difference in the physical structure of the sample with high sensitivity at low cost and quickly by analyzing the ionization behavior of the sample using MALDI-TOFMS. In addition, they have found that it is possible to realize an analysis method capable of evaluating a plurality of factors, and have completed the present invention. That is, the present invention includes the following configurations.

[1] An analysis method comprising an evaluation step of evaluating the physical structure of the sample based on the ionization behavior of the sample obtained by MALDI-TOFMS.

[2] The analysis method according to [1], wherein the sample is composed of a plurality of components and is evaluated for each component.

[3] The analysis method according to [1] or [2], wherein the sample is composed of a plurality of layers and is evaluated for each layer.

[4] The analytical method according to any one of [1] to [3], wherein the sample contains an organic film.

[5] The analysis method according to [4], wherein the organic film has a thickness of 0.1 nm to 2 μm.

[6] The analysis method according to any one of [1] to [5], wherein the sample is used in the field of organic electronics.

[7] The analysis method according to any one of [1] to [6], wherein the index of the ionization behavior is the ionic strength or the ion formation ratio obtained by MALDI-TOFMS.

[8] The ionization behavior is characterized in that it is obtained by changing any one or more selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere [1] to [7]. ] The analysis method according to any one of.

[9] The ionization behavior is characterized by being shown by a graph showing a change in ionic strength with a change in any one selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere. The analysis method according to any one of [1] to [8].

[10] The analysis method according to any one of [1] to [9], wherein the evaluation step is performed on a plurality of samples and the comparison step of comparing the results is included.

[11] The analysis method according to [10], wherein the plurality of samples are samples obtained by different production methods.

[12] The above-mentioned plurality of samples are samples obtained by being altered by any one selected from the group consisting of cooling, heat, light, electricity, pressure, reduced pressure, and leaving in the environment after production. The analysis method according to [10], which is a feature.

In one aspect of the present invention, the difference in the physical structure of the entire sample is quickly and inexpensively evaluated with high sensitivity for each component regardless of the number of components and the layer structure of the sample, and a plurality of factors are collectively evaluated. It has the effect of realizing a possible analysis method.

It is a figure which shows the graph which shows the ionic strength of the molecular ion of TPBi and Ir (t-buppy) 3 when the laser intensity is changed. It is a figure which shows the graph which shows the ionic strength of the molecular ion of TPBi and Ir (t-buppy) 3 when the laser frequency is changed. It is a figure which shows the graph which shows the ionic strength of B3PYMPM when the laser intensity is changed. It is a figure which shows the graph which shows the ionic strength of B3PYMPM when the laser frequency is changed. It is a figure which shows the mass spectrum of the vapor-deposited film of B3PYMPM when the laser intensity is changed. It is a figure which shows the mass spectrum of the coating film of B3PYMPM when the laser intensity is changed. It is a figure which shows the graph which shows the ionic strength of the dimer and the trimer of B3PYMPM when the laser intensity is changed. It is a figure which shows the graph which shows the ionic strength of the negative ion of B3PYMPM when the laser frequency is changed. It is a figure which shows the mass spectrum of the negative ion in the vapor deposition film of B3PYMPM when the laser frequency is changed. It is a figure which shows the mass spectrum of the negative ion in the coating film of B3PYMPM when the laser frequency is changed. It is a figure which shows the mass spectrum in the vapor-deposited film and the coating film of B3PYMPM when the laser frequency is changed. It is a figure which shows the measurement result by the synchrotron radiation soft X-ray absorption spectroscopy of the vapor-film deposition film and the coating film of B3PYMPM. It is a figure which shows the measurement result by GI-WAXS of the vapor deposition film and the coating film of B3PYMPM. It is a figure which shows the measurement result by GI-SAXS of the vapor-deposited film and the coating film obtained by mixing TPBi and Ir (t-buppy) 3. It is a figure which shows the measurement result of the organic multilayer thin film by MALDI-TOFMS.

Hereinafter, embodiments of the present invention will be described in detail, but these are aspects of the present invention, and the present invention is not limited to these contents. Unless otherwise specified in the present specification, "A to B" representing a numerical range means "A or more (including A and larger than A) and B or less (including B and smaller than B)".

The analysis method according to the embodiment of the present invention includes an evaluation step of evaluating the physical structure of the sample based on the ionization behavior of the sample obtained by MALDI-TOFMS.

[1. Evaluation process]
This step is a step of evaluating the physical structure of the sample based on the ionization behavior of the sample obtained by MALDI-TOFMS.

As shown in Examples described later, the present inventors observe a membrane sample (that is, a membrane sample having a similar chemical structure) obtained by different production methods using the same material by MALDI-TOFMS. , It was found that there is a difference in ionization behavior. Since these membrane samples use the same material, they have the same chemical composition. Therefore, it is considered that this difference in ionization behavior reflects the difference in physical structure.

Further, as shown in Examples described later, the present inventors may actually find a difference in physical structure when the membrane samples obtained by different production methods are evaluated by an analysis method other than MALDI-TOFMS. I'm checking. From the above, it is considered that according to this analysis method, it is possible to evaluate not the chemical structure of the sample but the physical structure of the sample.

Such an analysis method capable of evaluating the physical structure of a sample is very useful as a screening method for evaluating film quality in the development of a coating method, and is useful for improving the development speed and development accuracy.

Further, according to this analysis method, since MALDI-TOFMS is used, the cost is lower than that of the technique using synchrotron radiation X-rays as in Non-Patent Documents 2 and 3 described above. Further, since MALDI-TOFMS is used, the difference in the physical structure of the sample can be evaluated with high sensitivity, and a plurality of factors can be evaluated collectively.

<1-1. MALDI-TOFMS>
In the analysis method according to the embodiment of the present invention, MALDI-TOFMS is used. MALDI-TOFMS is an analysis method that combines a matrix-assisted laser desorption / ionization (MALDI) and a time-of-flight mass spectrometer (TOFMS).

In MALDI, first, a mixed crystal of a sample and a matrix (ionization aid) is prepared. Then, the mixed crystal is irradiated with a pulse of laser light. This adds protons or metal cations to generate ions. This ion is introduced into the mass spectrometer. Since MALDI uses a matrix, it is possible to perform mass spectrometry of polymer components that are easily decomposed by laser irradiation in the conventional ionization method. In the case of a component that is difficult to decompose, it can be measured without using a matrix.

TOFMS measures the mass-to-charge ratio (m / z) by measuring the time it takes for an accelerated charged particle (ion) to fly a certain distance. Ions with a large mass-to-charge ratio fly at low speed, and ions with a small mass-to-charge ratio fly at high speed. Therefore, ions with a large mass-to-charge ratio reach the ion detector later , and ions with a small mass-to-charge ratio reach the ion detector earlier . It is possible to measure the mass of the sample from the difference in flight time until it reaches this ion detector.

Conventionally, MALDI-TOFMS has been used for evaluating the chemical structure of a sample as described in Non-Patent Document 4. That is, MALDI-TOFMS was used for qualitative observation of the sample. On the other hand, in the analysis method according to the embodiment of the present invention, the physical structure of the sample is evaluated by analyzing the ionization behavior of the sample using MALDI-TOFMS.

Further, in MALDI-TOFMS, in order to improve the measurement sensitivity of the component to be measured, a pretreatment that changes the crystal state of the sample in various ways can be devised. Especially for a trace amount of a component or a component that is difficult to ionize, the detection sensitivity may change significantly due to a slight difference in the crystal state. Focusing on this point, the present inventors have found that the physical structure can be evaluated with high sensitivity by using MALDI-TOFMS. That is, the physical structure of the sample affects the direction and degree of transmission of the laser energy irradiated during ionization to each component constituting the sample. One embodiment of the present invention is an invention utilizing the fact that the difference in the way of transmission is reflected in the generation rate of ions detected by TOFMS.

<1-2. Sample>
The sample to be analyzed is not particularly limited as long as it is a sample containing an ionizable substance, and may be an organic substance, an inorganic substance, or a mixture thereof. The organic matter may be a single organic matter or a mixture of two or more different kinds of organic matter. Further, the inorganic substance may be a single inorganic substance or a mixture of two or more different kinds of inorganic substances. That is, the sample may be composed of a plurality of components. Then, in this case, each component may be evaluated by the analysis method according to the embodiment of the present invention. As described above, in the prior art, it may be difficult to evaluate a plurality of components for each component, but according to the analysis method according to the embodiment of the present invention, it is possible to evaluate each component.

Examples of the organic substance include aliphatic hydrocarbons, aromatic hydrocarbons, polycyclic aromatic hydrocarbons, compounds derived from heteroaromatic hydrocarbons or heteropolycyclic aromatic hydrocarbons, and rings in which rings are covalently bonded to each other. Examples thereof include linked compounds, compounds containing fullerene in the skeleton, compounds containing porphyrin or phthalocyanine in the skeleton, metal complex compounds containing these structures, and oligomers and polymers containing these structures.

Examples of the inorganic substance include those containing at least one of the following elements: [alkali metal element] Li, Na, K, Rb, Cs; [alkaline earth metal element] Be, Mg, Ca, Sr, Ba; [Lantanoid element] La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; [Actinoid element] Th, U; [Transition metal element] Sc , Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt , Au; [Boron group element] B, Al, Ga, In, Tl; [Carbon group element] Si, Ge, Sn, Pb; [Nictogen element] P, As, Sb, Bi; [Calcogen element] S, Se , Te; [halogen element] F, Cl, Br, I.

The shape of the sample is not particularly limited, but may be, for example, a powder sample or a film-shaped sample (hereinafter, also referred to as a film sample). Further, in the present specification, a membrane sample containing an organic substance may be referred to as an organic membrane. The organic film may contain an inorganic substance in addition to the organic substance. Further, the film sample may be a single-layer film or a multilayer film composed of two or more layers. That is, the sample may be composed of a plurality of layers. Then, in this case, the evaluation may be made for each layer by the analysis method according to the embodiment of the present invention. As described above, in the prior art, it may be difficult to evaluate a plurality of layers for each layer. As described in Non-Patent Document 5, according to LDI-TOFMS, ablation occurs on the surface of a sample by irradiating the sample with a laser. Therefore, according to the analysis method according to the embodiment of the present invention, it is possible to evaluate each layer by repeatedly irradiating and measuring the laser using MALDI-TOFMS.

From the above, according to the analysis method according to the embodiment of the present invention, it is possible to quickly evaluate the difference in the physical structure of the entire sample regardless of the number of constituent components and the layer structure of the sample.

Further, the sample may be made of an organic film, or may be provided with an organic film and other members. That is, the sample may contain an organic film. For example, the sample may contain members made of an inorganic substance such as an electrode and / or a solid sealing film.

The thickness of the membrane sample is not particularly limited, and may be 1 nm or less, 1 to 10 nm, 10 to 100 nm, 100 to 1000 nm, or 1 to 2 μm. It may be present, and may be 2 μm or more. In the present specification, a membrane sample having a thickness of 0.1 nm to 2 μm is also referred to as a thin film. The organic film may have a thickness of 0.1 nm to 2 μm. In the present specification, a sample that is an organic film and is a thin film is also referred to as an organic thin film.

The sample may be one used in the field of organic electronics. In the present specification, the material used in the field of organic electronics means, for example, a material used in an organic EL, an organic solar cell, an organic transistor, and the like. Organic thin films as described above are included in the materials used in the field of organic electronics.

Further, the above sample may contain, for example, the following components as components that can be used in the field of organic electronics: 2,2', 2''- (1,3,5-benzenetriyl)-. Tris (1-phenyl-1H-benzoimidazole) (hereinafter, also referred to as TPBi), iridium (III) tris (2- (4'-tert-butylphenyl) pyridinato) (hereinafter, also referred to as Ir (t-buppy) 3). ), Bis-4,6- (3,5-di-3-pyridylphenyl) -2-methylpyrimidine (hereinafter also referred to as B3PYMPM), Tris (8-quinolinolato) aluminum (hereinafter also referred to as Alq3), 4, 4'-bis (9H-carbazole-9-yl) biphenyl (hereinafter also referred to as CBP), N, N'-diphenyl-N, N'-di (m-tolyl) benzidine (hereinafter also referred to as TPD) and tris. (2-Phenylpyridinato) Iridium (III) (hereinafter, also referred to as Ir (ppy) 3) and the like.

B3PYMPM, Alq3, CBP, TPD and Ir (ppy) 3 are compounds represented by the following formulas (1) to (5), respectively.

The field in which the physical structure of the sample has a great influence on the performance of the product is not limited to the field of organic electronics. That is, the sample to be the subject of the analysis method according to the embodiment of the present invention is not limited to that used in the field of organic electronics. Similar to organic electronics, this also applies to the battery field such as storage batteries and fuel cells in which the flow of electrons or ions is generated. Also, films, resins, rubbers, carbon materials and metals, as well as films, resins, rubbers, carbon materials and metals whose physical structure affects gas permeability such as water vapor and oxygen, as well as mechanical strength against tension, tearing, twisting, pressurization, depressurization and temperature. This also applies to fields where composite materials are used.

When the sample is a membrane sample, the manufacturing method thereof is not particularly limited. According to the analytical method according to one embodiment of the present invention, it is possible to evaluate the difference in physical structure between the samples obtained by different production methods. For example, the membrane sample may be at least one of a coating film and a vapor-deposited film.

The thin-film deposition film is intended to be a film produced by a thin-film deposition method. Examples of the vapor deposition method include a physical vapor deposition method (PVD) and a chemical vapor deposition method (CVD). Examples of PVD include a vacuum vapor deposition method, a sputtering method, an ion plating method, a molecular beam epitaxy method (MBE), a laser ablation method, and the like. Examples of the CVD include thermal CVD, optical CVD, plasma CVD, and metalorganic vapor deposition (MOCVD).

The coating film is intended to be a film produced by the coating method. Examples of the coating method include an inkjet method, a spin coating method, a die coating method, a spraying method, a screen printing method and the like.

In addition, the membrane sample may be produced by a plating method, anodizing, a sol-gel method, or the like.

<1-3. Physical structure>
The analytical method according to one embodiment of the present invention evaluates the physical structure of a sample. As used herein, the physical structure of a sample is intended to be a property in which differences may appear between samples made of the same material. For example, the physical structure of a sample includes properties that are made of the same material and can show differences between samples obtained by different manufacturing methods. The above physical structure excludes a chemical structure (for example, the structure of a terminal group of a polymer, the molecular weight distribution, the composition of a copolymer, etc.).

The physical structure comprises, for example, one or more selected from the group consisting of molecular orientation, density, degree of mixing, crystallinity, radical generation state, charge trap state and interface state. May be good. When these physical structures are different, the way energy is transmitted by the laser of MALDI-TOFMS may be different. Therefore, it is presumed that these physical structures can be evaluated by the analytical method according to the embodiment of the present invention. These physical structures are important, for example, as the film quality of organic films. That is, the analytical method according to the embodiment of the present invention can evaluate a plurality of factors collectively.

The molecular orientation indicates whether the molecules constituting the sample are randomly oriented or oriented in a specific direction (for example, in a direction parallel to or perpendicular to the substrate on which the film is formed).

The density is an index indicating whether or not the molecule is clogged as an average of the entire sample. In other words, density is an indicator of whether or not there is a gap. Cohesiveness is an index indicating whether or not there is a state in which molecules are attracted to each other and aggregated in a certain part in the whole sample, or whether the amount of the part is large or small. It becomes. The cohesiveness also includes whether or not there are gaps (low density) and no gaps (high density) in the sample (whether or not the density is biased in the sample). It means to do.

The degree of mixing indicates, for example, whether or not a plurality of components contained in the sample are uniformly mixed in the sample as a whole. "Whether or not they are uniformly mixed" means that there are some parts in the sample where the component ratio is constant and some parts where the component ratio is not constant.

Crystallinity indicates whether or not it is crystallized. The degree of molecular packing in the crystal is also included in the physical structure.

The radical generation state indicates the presence / absence and distribution of radicals in the sample.

The state of the charge trap represents the presence / absence and distribution of the captured charge.

The state of the interface is the distance, amount, and attractive force of one component and another component in the case of a sample composed of multiple components or multiple layers (multilayer film). Indicates whether they are in close contact with each other. In the case of a sample composed of a multilayer film, the interface of each layer includes a state in which the components of the upper layer and the components of the lower layer are mixed during or after the preparation of the sample.

The physical structure also includes whether or not the molecules are bound by a weak force and whether or not the molecules are solvated.

Such physical structures may show differences between the inside and the surface of the sample. In addition, a difference may be seen between the upper layer portion and the lower layer portion (interface) of the membrane sample.

Further, in the coating film, the degree of residual solvent differs depending on whether or not it is dried, which may affect packing. Further, in the multilayer film obtained by the coating method, the vicinity of the interface of each layer may be dissolved due to the influence of the residual solvent. On the other hand, this does not occur with the multilayer film obtained by the vapor deposition method. As a result, it is possible that a difference in physical structure occurs between the vapor-film deposition film and the coating film.

In the conventional analysis method, only a limited item of the above-mentioned physical structure can be evaluated for one analysis method. On the other hand, in the analysis method according to the embodiment of the present invention, various physical structures as described above can be evaluated.

<1-4. Ionization behavior>
In the analysis method according to the embodiment of the present invention, the ionization behavior of the sample obtained by MALDI-TOFMS is used. As used herein, the ionization behavior is intended to be the behavior of ions when the components contained in the sample are ionized. Examples of the index of ionization behavior include the ionic strength obtained by MALDI-TOFMS or the ion production ratio.

The ions of interest in the analysis of ionization behavior are not particularly limited as long as they are the ions of the components contained in the sample. Since MALDI-TOFMS is used in the analysis method according to the embodiment of the present invention, attention is paid to the ionization behavior of a specific component in the sample based on the mass-to-charge ratio even if the sample is a mixture of a plurality of components. Can be analyzed. The ion of interest may be, for example, an ion of a component that can be used in the above-mentioned field of organic electronics.

The ions of interest are, for example, molecular ions (M ⁺ and M- ⁾ of the components contained in the sample, protonated molecules ([M + H] ⁺ ), sodium ion addition molecules ([M + Na] ⁺ ), and dehydrated molecules. ([MH] ⁺ ), polyvalent protonated molecule ([M + nH] ^{n +} ), deprotonated molecule ([MH] ⁻ ), polyvalent deprotonated molecule ([M—nH] ⁿ⁻ ), etc. Can be mentioned. Further, the ion of interest may be another addition ion, a fragment ion, a monomer, a dimer, a trimer, a tetramer, or a multimer of more than that. You may. It may be the one to which those ions are added. In the case of a sample containing a plurality of components, ions derived from the components may be added to each other. Ions derived from the solvent remaining in the sample prepared by the coating method may be added to the ions derived from the component derived from the sample. Ions derived from impurities unintentionally mixed may be added to ions derived from components derived from the sample when or after the sample is prepared. In the case of a sample containing an inorganic substance and an organic substance, an ion corresponding to the complex thereof may be used. Ions that have been altered by heat, light and / or electricity after sample preparation are also included. The above-mentioned ion may be a positive ion or a negative ion.

The ionic strength of each of these ions or the generation ratio of each ion may be used as an index of ionization behavior. For example, the index of the ionization behavior is preferably ion intensity, fragment ion formation ratio, addition ion formation ratio, positive ion to negative ion ratio, or protonation molecule to molecular ion formation ratio. These indicators can be suitably used for the evaluation of the physical structure.

The ionization behavior may be obtained under certain specific conditions, or may be obtained under a plurality of conditions. Preferably, the ionization behavior is obtained under a plurality of conditions, for example, it is obtained by changing a certain condition stepwise (or continuously). Specifically, the ionization behavior is preferably obtained by changing any one or more selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere. Those skilled in the art will appreciate that these conditions can be changed in the analysis by MALDI-TOFMS and that the ionization behavior can change with the change of these conditions. The physical structure of the sample can be evaluated by analyzing the change in the index of the ionization behavior due to the change in these conditions. The range in which these conditions are changed is not particularly limited, and may be appropriately selected depending on the type of sample, the type of ion of interest, and the like, and examples are shown below.

The laser intensity may be 0.1 to 10%, 10 to 60%, 20 to 55%, or 35 to 45, where the maximum intensity of the oscillating laser is 100%. It may be%, and it may be 40-55%. The laser intensity is not limited as long as the power can oscillate the laser. Generally, the higher the laser intensity, the greater the energy received by the sample and the easier it is to ionize, resulting in higher ionic strength. When the laser intensity is changed, it may be changed by 1% or by 10%.

The laser frequency may be 0.1 to 1000000 Hz or 10 to 1000 Hz. When the laser frequency is changed, it may be changed by 10 Hz or 100 Hz. The laser frequency is not limited as long as the laser can oscillate.

The laser wavelength may be 200 to 380 nm, 10 to 200 nm, 10 to 121 nm, 380 to 780 nm, 780 to 1400 nm, or 1400. It may be up to 3000 nm. The laser wavelength is not limited as long as the wavelength can oscillate the laser. When the laser wavelength is changed, it may be changed by 5 nm or by 50 nm.

The temperature may be absolute zero to -196 ° C, 196 to 0 ° C, 0 to 25 ° C, 25 to 40 ° C, 40 to 100 ° C. It may be 100 ° C. or higher. When the temperature is changed, it may be changed by 5 ° C. or by 10 ° C.

The measurement atmosphere may be nitrogen, argon, helium, air, oxygen or hydrogen.

According to the analysis method according to the embodiment of the present invention, since MALDI-TOFMS is used, various indicators of ionization behavior can be used as described above. Similarly, the ionization behavior can be evaluated when various conditions are changed. Therefore, it is possible to evaluate the sample from various viewpoints. That is, it is considered that various factors that affect the physical structure of the sample can be evaluated according to the analysis method according to the embodiment of the present invention, as compared with the conventional technique that can evaluate only a limited number of factors.

The ionization behavior may be represented as a graph or mass spectrum. This makes it easier to visually understand the ionization behavior.

The ionization behavior is preferably shown by a graph showing the change in ionic strength with any one change selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere. This makes it easy to visually understand the effect of ionization behavior on the physical structure of the sample. Examples of the graph include those in which the vertical axis represents ionic strength and the horizontal axis represents laser intensity, laser frequency, laser wavelength, temperature, measurement atmosphere, and the like. In this case, the ionic strength of the above-mentioned specific ion or the integrated ionic strength over the entire mass spectrum may be used as the vertical axis.

Further, as the mass spectrum, the one in which the ionic strength is on the vertical axis and the mass-to-charge ratio is on the horizontal axis can be mentioned. A plurality of mass spectra obtained when the above-mentioned laser intensity, laser frequency, laser wavelength, temperature or measurement atmosphere are changed may be used.

[2. Comparison process]
The analysis method according to the embodiment of the present invention may include a comparison step of performing the above evaluation step on a plurality of samples and comparing the results. The plurality of samples may be any sample for which it is desired to investigate whether or not there is a difference in the physical structure. This makes it possible to compare differences in physical structure between samples based on the ionization behavior.

For example, the plurality of samples may be samples obtained by different production methods. This makes it possible to compare the differences in physical structure due to the manufacturing method. Specifically, the plurality of samples may be a thin-film deposition film and a coating film.

Further, the plurality of samples may be samples obtained by being altered by any one selected from the group consisting of cooling, heat, light, electricity, pressure, reduced pressure and leaving in the environment after production. .. This makes it possible to compare differences in physical structure due to cooling, heat, light, electricity and / or leaving in the environment after manufacture. In addition, in this specification, leaving in an environment is intended to leave a sample in a specific environment. The specific environment refers to a certain environmental condition, for example, an environment of constant temperature and humidity at atmospheric pressure is intended.

The result of the evaluation step may be represented as a graph or mass spectrum as described above. This makes it possible to visually compare differences in physical structure.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[1. Sample preparation]
A thin-film deposition film was produced by a vacuum-film deposition method using a material described later. In addition, a coating film was produced by a spin coating method using the same material. Specifically, after the material was dissolved in a solvent, a coating film was prepared at a rotation speed of 2000 rpm. The coating film was dried (baked) at 110 ° C. for 30 minutes to prepare a coating film. Both the vapor deposition film and the coating film were made on a silicon substrate.

[2. Measurement by MALDI-TOFMS]
The ionic strength of the vapor-deposited film and the coating film prepared as described above was measured using MALDI-TOFMS. Here, the following [3. Ionization behavior with changes in laser intensity (1)] The common conditions in the measurement by MALDI-TOFMS carried out in the following will be described.

A thin-film deposition film and a coating film were placed on the measurement plate, and the measurement plate was installed in the MALDI-TOFMS apparatus. As the MALDI-TOFMS apparatus, JMS-S3000 manufactured by JEOL Ltd. was used.

For more detailed conditions, see the following [3. Ionization behavior with changes in laser intensity (1)] will be described below.

[3. Ionization behavior with changes in laser intensity (1)]
Using MALDI-TOFMS, the ionic strength was measured with the laser frequency set to 10 Hz and the laser intensity varied from 19% to 40%. Measurement was performed on a sample formed into a film having a thickness of 25 nm using 85% by weight of TPBi and 15% by weight of Ir (t-buppy) 3 as materials. Toluene was used as a solvent for dissolving the material at the time of preparing the coating film. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 1 is a diagram showing a graph showing the ionic strength of the molecular ions of TPBi and Ir (t-buppy) 3 when the laser intensity is changed. The vertical axis represents the ionic strength and the horizontal axis represents the laser intensity. The rhombus (diamond) represents the vapor-film deposition film, and the triangle represents the coating film.

FIG. 1A is a graph showing the ionic strength of the molecular ion of TPBi having m / z 653. As can be seen from (a) of FIG. 1, when focusing on TPBi, the vapor-deposited film had a higher ionic strength than the coating film in the range where the laser intensity was high.

FIG. 1B is a graph showing the ionic strength of the molecular ion of Ir (t-buppy) 3, which is m / z 821. As can be seen from (b) of FIG. 1, when focusing on Ir (t-buppy) 3, the difference between the vapor-film deposition film and the coating film was smaller than that of TPBi.

As described above, the difference between the vapor-deposited film and the coated film can be detected by analyzing the ionization behavior when the laser intensity is changed by the analysis method according to the embodiment of the present invention. Since the same material is used for the vapor-deposited film and the coating film, it is considered that the difference between them is not due to the chemical structure but due to the physical structure. That is, according to the analysis method according to the embodiment of the present invention, the physical structure of the sample can be evaluated using MALDI-TOFMS.

Further, the analysis method according to the embodiment of the present invention can be applied even when the sample is composed of a plurality of components. Further, according to the analysis method according to the embodiment of the present invention, it is possible to analyze each component. For example, this time, a difference in ionization behavior was observed between TPBi and Ir (t-buppy) 3. Therefore, it is considered that the physical structure can be evaluated with high sensitivity for each component of interest.

[4. Ionization behavior with changes in laser frequency (1)]
Using MALDI-TOFMS, the ionic strength was measured by changing the laser frequency from 10 Hz to 1000 Hz with the laser intensity set to 21%. As a sample, [3. Ionization behavior with changes in laser intensity (1)] was used. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 2 is a diagram showing a graph showing the ionic strength of the molecular ions of TPBi and Ir (t-buppy) 3 when the laser frequency is changed. The vertical axis represents the ionic strength and the horizontal axis represents the laser frequency. The diamonds represent the vapor deposition film and the triangles represent the coating film.

FIG. 2A is a graph showing the ionic strength of the molecular ion of TPBi having m / z 653. As can be seen from (a) of FIG. 2, when focusing on TPBi, the vapor-filmed film had a higher ionic strength than the coated film.

FIG. 2B is a graph showing the ionic strength of the molecular ion of Ir (t-buppy) 3, which is m / z 821. As can be seen from (b) of FIG. 2, the vapor-filmed film had a higher ionic strength than the coated film.

From the above, it is also possible to evaluate the difference in the physical structure of the sample by analyzing the ionization behavior when the laser frequency is changed by the analysis method according to the embodiment of the present invention. That is, according to the analysis method according to the embodiment of the present invention, the physical structure can be evaluated using various parameters.

Focusing on the tendency of the ionic strength with respect to the change in frequency, in FIG. 2 (b) corresponding to Ir (t-buppy) 3, the ionic strength is linearly positively correlated with the entire region of the measured frequency. Is shown. On the other hand, in FIG. 2 (a) corresponding to TPBi, the ionic strength shows a positive correlation up to 500 Hz, but it is greatly reduced at 1000 Hz. In other words, it appears that the influence on the change of frequency differs depending on the compound. Therefore, it is considered that factors affecting the film quality (physical structure) can be evaluated from different viewpoints by changing the type of the compound of interest.

Further, when focusing on Ir (t-buppy) 3 in (b) of FIG. 1 described above, there was almost no difference between the vapor-filmed film and the coating film, but in (b) of FIG. 2, Ir (t-buppy) 3 was obtained. Even when we focused on it, we found a difference between the vapor-film deposition film and the coating film. Since different results were obtained in FIGS. 1 and 2 as described above, it is considered that evaluation can be performed from different viewpoints depending on whether the laser intensity is changed or the laser frequency is changed.

[5. Ionization behavior with changes in laser intensity (2)]
Using MALDI-TOFMS, the ionic strength was measured with the laser frequency set to 10 Hz and the laser intensity varied from 35% to 54%. Measurement was performed on a sample formed into a film at 30 nm using B3PYMPM as a material. Chloroform was used as a solvent for dissolving the material at the time of preparing the coating film. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 3 is a diagram showing a graph showing the ionic strength of B3PYMPM which is m / z 555 ([M + H] ⁺ ). The vertical axis represents the ionic strength and the horizontal axis represents the laser intensity. The diamonds represent the vapor deposition film and the squares represent the coating film. From FIG. 3, when focusing on B3PYMPM, although the difference between the vapor-film deposition film and the coating film was small, a difference was observed in the range of the laser intensity of 41 to 44%. Further, from this, it can be seen that the ionization behavior of B3PYMPM tends to be different from the ionization behavior of TPBi described above. Therefore, it is considered that factors affecting the film quality can be evaluated from different viewpoints by changing the type of the compound of interest.

[6. Ionization behavior with changes in laser frequency (2)]
In FIG. 3 described above, a slight difference in ionic strength was observed between the vapor-deposited film and the coating film in the range of the laser intensity of 41 to 44%. Therefore, using MALDI-TOFMS, the ionic strength was measured by changing the laser frequency from 10 Hz to 1000 Hz with the laser intensity set to 44%. As a sample, [5. Ionization behavior with changes in laser intensity (2)] was used. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 4 is a diagram showing a graph showing the ionic strength of B3PYMPM having m / z 554 (M ⁺ ). The vertical axis represents the ionic strength and the horizontal axis represents the laser frequency. The diamonds represent the vapor deposition film and the squares represent the coating film. In FIG. 4, the coating film had a higher ionic strength than the vapor-deposited film. From this, it can be seen that the ionization behavior of B3PYMPM tends to be different from the ionization behavior of TPBi described above.

In addition, while the ionic strength of the vapor-film deposition film is almost constant with respect to changes in frequency, the ionic strength of the coating film is high up to 100 Hz, the ionic strength is greatly reduced at 250 Hz, and the ionic strength is almost constant up to 1000 Hz. rice field. It can be seen that these results show a tendency different from the ionization behavior of TPBi and Ir (t-buppy) 3 described above. That is, it is considered that factors affecting the film quality can be evaluated from different viewpoints by changing the type of the compound of interest.

[7. Ionization behavior with changes in laser intensity (3)]
Using MALDI-TOFMS, the ionic strength was measured with the laser frequency set to 10 Hz and the laser intensity varied from 40% to 44%. As a sample, [5. Ionization behavior with changes in laser intensity (2)] was used.

FIG. 5 is a diagram showing a mass spectrum of a thin-film vapor deposition film of B3PYMPM when the laser intensity is changed. (A) to (c) of FIG. 5 represent the case where the laser intensity is 40%, 41% and 44%, respectively.

FIG. 6 is a diagram showing a mass spectrum of a coating film of B3PYMPM when the laser intensity is changed. 6 (a) to 6 (c) represent the cases where the laser intensities are 40%, 41% and 44%, respectively.

In FIGS. 5 and 6, the polymer peak appeared as the laser intensity increased. Specifically, peaks of macromolecules such as dimers and trimers appeared. Further, in FIG. 6, as the laser intensity increased, the decomposition peaks (peaks of fragment ions) of small molecules increased. That is, it is considered that by using the mass spectrum, the factors affecting the film quality can be evaluated from a viewpoint different from that of the above-mentioned Examples.

In FIGS. 5 and 6, the peak surrounded by the dotted line represents a peak not seen in the powder measurement (data is not shown). Further, in FIG. 6, the peak surrounded by the alternate long and short dash line represents a peak not seen in FIG. 5 (that is, the vapor-deposited film). In this way, the difference between the vapor-deposited film and the coated film can be detected from the mass spectrum of the film sample.

[8. Ionization behavior of dimers and trimers]
Using MALDI-TOFMS, the ionic strength was measured with the laser frequency set to 10 Hz and the laser intensity varied from 35% to 54%. As a sample, [5. Ionization behavior with changes in laser intensity (2)] was used. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 7 is a diagram showing a graph showing the ionic strength of the dimer and the trimer of B3PYMPM when the laser intensity is changed. The vertical axis represents the ionic strength and the horizontal axis represents the laser intensity. The diamonds represent the vapor deposition film and the squares represent the coating film.

FIG. 7A is a graph showing the ionic strength of the dimer of B3PYMPM, which is m / z 1107 ([2M + H] ⁺ ). FIG. 7B is a graph showing the ionic strength of the B3PYMPM trimer at m / z 1659 ([3M + H] ⁺ ).

In both (a) and (b) of FIG. 7, in the range where the laser intensity is high (for example, the range where the laser intensity is 45% or more), the vapor-deposited film has a higher ionic strength than the coating film. This result is different from the result of molecular ions in which the difference between the vapor-deposited film and the coating film was small as shown in FIG. In addition, the difference was larger in the trimer than in the dimer. That is, by focusing on dimers, trimers, and the like, it is considered that factors affecting the film quality can be evaluated from a viewpoint different from that of the above-mentioned examples.

[9. Behavior of negative ions]
Using MALDI-TOFMS, the ionic strength was measured by changing the laser frequency from 10 Hz to 1000 Hz with the laser intensity set to 44%. As a sample, [5. Ionization behavior with changes in laser intensity (2)] was used. The ionic strength is an average value of measured values obtained from a plurality of points on each sample.

FIG. 8 is a diagram showing a graph showing the ionic strength of the negative ion of B3PYMPM having m / z 554 (M ⁻ ).

Here, FIG. 4 described above shows the ionic strength of positive ions. In FIG. 4, the difference between the vapor-filmed film and the coating film was large in the range where the laser frequency was small, whereas in FIG. 8, the difference between the vapor-filmed film and the coating film was large in the range where the laser frequency was large. Further, as can be seen from FIGS. 4 and 8, the difference is larger in the negative ion than in the positive ion. Therefore, when focusing on the negative ions of B3PYMPM, it is considered that the difference in physical structure can be evaluated with higher sensitivity than when focusing on the positive ions.

FIG. 9 is a diagram showing a mass spectrum of negative ions in a vapor-deposited film of B3PYMPM when the laser frequency is changed with the laser intensity set to 41%. 9 (a) to 9 (c) represent the cases where the laser frequencies are 10 Hz, 100 Hz, and 1000 Hz, respectively.

FIG. 10 is a diagram showing a mass spectrum of negative ions in a coating film of B3PYMPM when the laser frequency is changed with the laser intensity being 41%. FIGS. 10A to 10C represent cases where the laser frequencies are 10 Hz, 100 Hz, and 1000 Hz, respectively.

In both FIGS. 9 and 10, small molecule fragment peaks decrease as the laser frequency increases, showing a clean mass spectrum pattern at 1000 Hz. Here, at any frequency, the coating film sample of FIG. 10 has a smaller intensity of the small molecule fragment than the vapor-deposited film sample of FIG. 9, and shows a clean pattern. Even when focusing on the mass spectrum in this way, the difference in physical structure can be evaluated.

[10. Molecular ion]
Using MALDI-TOFMS, the ionic strength was measured by changing the laser frequency from 20 Hz to 250 Hz with the laser intensity set to 41%. As a sample, [5. Ionization behavior with changes in laser intensity (2)] was used. FIG. 11 is a diagram showing mass spectra of a thin-film film and a coating film of B3PYMPM when the laser frequency is changed.

(A) and (b) of FIG. 11 represent the mass spectrum of the vapor-filmed film, and represent the cases where the laser frequencies are 20 Hz and 250 Hz, respectively.

11 (c) and 11 (d) represent the mass spectra of the coating film, and represent the cases where the laser frequencies are 20 Hz and 250 Hz, respectively.

In both the thin-film deposition film and the coating film, the increase in ionic strength with the increase in the laser frequency was larger in M ⁺ than in [M + H] ⁺ , and the degree was more remarkable in the coating film than in the coating film. This change is thought to be related to the presence or absence of intramolecular or intramolecular protons. By paying attention to the types of ions, it is considered that factors affecting the film quality can be evaluated from a viewpoint different from that of the above-mentioned examples.

[11. Confirmation of molecular orientation]
The molecular orientation of the vapor-deposited film and the coating film was evaluated using synchrotron radiation soft X-ray absorption spectroscopy. A thin-film deposition film (vacuum-film deposition method, thickness 50 nm) and a coating film (spin-coat method, 1000 rpm, thickness 10 nm) were each formed on a silicon substrate using B3PYMPM as a material, and these were used as samples. As a measuring device, Advanced Light Source (ALS) BL6.3.2 was used, and the measurement was performed by the total electron yield method. In the measurement, the incident angle of the soft X-ray was changed from 30 to 90 degrees. The evaluation was performed in the NK absorption edge region. As a result, anisotropy evaluation focusing on the N atom was performed.

FIG. 12 is a diagram showing the measurement results of the thin-film vapor deposition film and the coating film of B3PYMPM by synchrotron radiation soft X-ray absorption spectroscopy. The vertical axis of FIG. 12 represents the strength standardized based on the strength of σ *.

FIG. 12A shows the measurement result of the thin-film deposition film. In FIG. 12A, the relative intensity of π * decreased as the incident angle of the soft X-rays approached 90 degrees. From this, it is considered that in the thin-film deposition film, the π orbitals project perpendicular to the substrate. That is, the vapor-filmed film exhibits horizontal orientation.

FIG. 12B shows the measurement result of the coating film. In FIG. 12B, no change was observed in the spectral shape even when the incident angle of the soft X-ray was changed. That is, the coating film exhibits random orientation.

As described above, it was clarified that the molecular orientations of the vapor-deposited film and the coating film are different even if the materials are the same. That is, the vapor-filmed film and the coated film have different physical structures, as observed in the above-mentioned MALDI-TOFMS.

[12. Confirmation of crystallinity]
The crystallinity of the vapor-deposited film and the coating film was evaluated using GI-WAXS (small-angle incident wide-angle X-ray scattering). A thin-film deposition film (vacuum-film deposition method) and a coating film (spin-coating method, 1000 rpm) having a thickness of 30 nm were prepared on a silicon substrate using B3PYMPM as a material, and these were used as samples. BL08B2 of SPring-8 was used as a measuring device, and the wavelength was 1.0 Å, the camera length (distance between the sample and the detector) was 125.4 mm, the incident angle was 0.1 degrees, and the exposure time was 10 seconds.

FIG. 13 is a diagram showing the measurement results of the thin-film vapor deposition film and the coating film of B3PYMPM by GI-WAXS. In the measurement result by GI-WAXS, when the peaks match, it can be judged that the crystallinity is the same. According to FIG. 13, in the vapor-filmed film, peaks are seen at ~ 3.7 Å and ~ 3.2 Å, which are considered to correspond to π-stacking. On the other hand, such a peak is not seen in the coating film.

Therefore, it was clarified that the crystallinity of the vapor-deposited film and the coating film is different even if the materials are the same. That is, the vapor-filmed film and the coated film have different physical structures, as observed in the above-mentioned MALDI-TOFMS.

[13. Confirmation of the physical structure of the mixed membrane sample]
The crystallinity of the vapor deposition film and the coating film was evaluated using GI-SAXS (small angle incident small angle X-ray scattering). As a sample, [3. Ionization behavior with changes in laser intensity (1)] was used.

FIG. 14 is a diagram showing measurement results by GI-SAXS of a thin-film deposition film and a coating film obtained by mixing TPBi and Ir (t-buppy) 3. From FIG. 14, different curves can be obtained between the vapor-film deposition film and the coating film. Therefore, it can be seen from FIG. 14 that the vapor-film deposition film and the coating film have different physical structures.

More specifically, the vapor deposition film and the coating film have different densities or uniformitys, different orientations, different molecular structures (intramolecular bond angles or bond lengths), or intramolecular distances and uniformity. Is considered to be different. Further, since the curve of the vapor-film vapor film has fringes, it is considered that the periodic structure is uniform (high uniformity).

[14. Evaluation of organic multilayer thin film]
A sample (that is, an organic multilayer thin film) in which a TPD film, a mixed film of CBP and Ir (ppy) 3, an Alq3 film, and an Al film (electrode) are formed in this order on a glass substrate is measured by MALDI-TOFMS. rice field.

FIG. 15 is a diagram showing the measurement results (mass spectrum) of the organic multilayer thin film by MALDI-TOFMS. From FIG. 15, it can be seen that all the components used can be detected even when the sample is composed of a plurality of layers. That is, the analysis method according to the embodiment of the present invention can be applied regardless of the layer structure of the sample.

One aspect of the present invention can be used for analysis of the physical structure of a sample in various fields such as organic electronics.

Claims (7)

It includes an evaluation step of evaluating the physical structure of the sample based on the ionization behavior of the sample obtained by LDI- TOFMS .
The index of the ionization behavior is the ionic strength or the ion formation ratio obtained by LDI-TOFMS.
The physical structure is one or more selected from the group consisting of molecular orientation, density, degree of mixing, crystallinity, radical generation state, charge trap state and interface state.
The ionization behavior is obtained by changing any one or more selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere.
The above sample contains an organic film and contains
The organic film has a thickness of 0.1 nm to 2 μm and has a thickness of 0.1 nm to 2 μm.
An analysis method comprising a comparison step of performing the above evaluation step on a plurality of samples and comparing the results . The analysis method according to claim 1, wherein the sample is composed of a plurality of components and is evaluated for each component. The analysis method according to claim 1 or 2, wherein the sample is composed of a plurality of layers and is evaluated for each layer. The analysis method according to any one of claims 1 to 3 , wherein the sample is used in the field of organic electronics. The above-mentioned ionization behavior is characterized by being shown by a graph showing a change in ionic strength with a change in any one selected from the group consisting of laser intensity, laser frequency, laser wavelength, temperature and measurement atmosphere. The analysis method according to any one of 1 to 4 . The analysis method according to any one of claims 1 to 5, wherein the plurality of samples are samples obtained by different production methods. The plurality of samples are characterized in that they are samples obtained by being altered by any one selected from the group consisting of cooling, heat, light, electricity, under pressure, under reduced pressure and leaving in the environment after production. The analysis method according to any one of claims 1 to 6 .

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