Method for evaluating oxygen partial pressure, and device for evaluating oxygen partial pressure

Abstract

Provided is a method for quickly and easily evaluating oxygen partial pressure in a range of 1-160 mmHg using a phosphorescent material. The method for evaluating oxygen partial pressure uses phosphorescent particles having an average particle diameter of 9.56 µm or less, and evaluates the oxygen partial pressure on the basis of a difference in behavior related to the attenuation of light emission intensity with the passage of time after stoppage of excitation light irradiation of the phosphorescent particles.

Description

Method for assessing oxygen partial pressure and device for assessing oxygen partial pressure

[0001] The present invention relates to a method and an apparatus for evaluating oxygen partial pressure, and more particularly to a method and an apparatus for evaluating oxygen partial pressure using a phosphorescent material.

[0002] Phosphorescence is a phenomenon in which a substance absorbs irradiated light, stores the light as energy, and continues to emit light for a while even after the light irradiation has stopped. Until now, inorganic compounds have been known as materials that exhibit phosphorescence at room temperature, but organic compounds have also been proposed. Phosphorescence in organic compounds is mainly a phenomenon called phosphorescence, which is defined as light emission based on a spin-forbidden transition from an excited triplet state to a ground singlet state.

[0003] In recent years, many organic compound materials that exhibit long-lifetime room-temperature phosphorescence (e.g., emission lifetime of 100 milliseconds (ms) or more) have been reported. Compared to the delayed fluorescence of existing phosphorescent materials that utilize charge separation and subsequent recombination, such long-lifetime room-temperature phosphorescence can increase the intensity of excitation light and exhibit greater phosphorescence brightness immediately after the irradiation of the excitation light is stopped. Therefore, by utilizing such long-lifetime room-temperature phosphorescence and measuring the phosphorescence image immediately after the irradiation of the excitation light is stopped using a two-dimensional detector, high-resolution luminescence imaging that does not rely on autofluorescence is possible (Non-Patent Document 1).

[0004] Various molecules that exhibit specific long-life room-temperature phosphorescence or phosphorescent materials using such molecules have been reported so far.

[0005] For example, Non-Patent Document 2 reports the phosphorescent properties in the atmosphere of a material obtained by doping a low-molecular amorphous medium having hydrogen bonding ability with a specific molecule that exhibits long-life room-temperature phosphorescence.

[0006] Furthermore, Non-Patent Document 3 reports the phosphorescent properties in the atmosphere of a material obtained by doping a polymer amorphous medium having hydrogen bonding ability with a specific molecule that exhibits long-life room-temperature phosphorescence.

[0007] Furthermore, Non-Patent Document 4 reports that, for a white aqueous suspension (emulsion) in which predetermined molecules exhibiting long-life room-temperature phosphorescence are dispersed in an amorphous polymer, the intensity of the room-temperature phosphorescence changes significantly depending on the change in oxygen concentration of the aqueous solution.

[0008] Furthermore, Non-Patent Document 5 reports the phosphorescent properties in the atmosphere of a solid film obtained by dispersing specific molecules that exhibit long-life room-temperature phosphorescence in polyacrylonitrile, which is known to have high gas barrier properties.

[0009] Furthermore, Non-Patent Documents 6 to 8 each report the phosphorescent properties of a material obtained by dispersing predetermined molecules that exhibit long-life room-temperature phosphorescence in a molecular crystal.

[0010] Furthermore, Non-Patent Documents 9 and 10 report the phosphorescent properties in the atmosphere of a film of a material in which specific molecules exhibiting long-life room-temperature phosphorescence are dispersed in a molecular crystal, and an aqueous solution in which nanoparticles of the material are dispersed.

[0011] Furthermore, Non-Patent Document 11 reports an example of long-lifetime room-temperature phosphorescence from silica-coated carbon nanodots in aqueous solution and their application to in vivo imaging after injection into a biological sample.

[0012] Adv. Mater. 2020, 32, 2001348.Adv. Funct. Mater. 2013, 23, 3386.J. Phys. Chem. C 2023, 127, 3861.Chem. Engineering Journal 2023, 474, 145809.Adv. Funct. Mater. 2021, 31, 2101656.Adv. Sci. 2019, 6, 1900410.Nat. Mater. 2015, 14, 685.Adv. Mater. 2017, 29, 1606665.Nat. Mater. 2021, 20, 1539.Adv. Sci. 2023, 10, 2304374.Chem. Mater. 2019, 31, 9887.

[0013] In recent years, application technologies have been reported that use luminescent materials to evaluate the oxygen partial pressure (oxygen concentration) of various tissues in a biological environment. Such technologies are basically based on the principle that luminescence characteristics change depending on the oxygen partial pressure (i.e., luminescence responsiveness to oxygen partial pressure).

[0014] In particular, it is expected that the above technology will also use phosphorescent materials. In this case, the phosphorescent phenomenon (also called "afterglow") can be utilized, and the principle of phosphorescent materials, namely, the behavior (also called "decay") of the decay of luminescence intensity (phosphorescent intensity, phosphorescent intensity) over time after irradiation of the phosphorescent material with excitation light in the surrounding environment changes depending on the oxygen partial pressure in the surrounding environment. As an example, the principle of phosphorescent materials, namely, the higher the oxygen partial pressure in the surrounding environment, the shorter the afterglow time (or phosphorescent life) of the phosphorescent material in the surrounding environment after irradiation of excitation light in the surrounding environment is stopped, can be utilized.

[0015] However, based on previous findings, phosphorescent materials are unlikely to exhibit the phosphorescence phenomenon (their phosphorescence lifetime is extremely short), particularly when the oxygen partial pressure is in the range of 1 mmHg or more and 160 mmHg or less. Even if they do exhibit the phosphorescence phenomenon, it has been difficult to confirm the tendency for the afterglow time after the excitation light irradiation to become shorter as the oxygen partial pressure increases. That is, accurate evaluation of the oxygen partial pressure using a specific phosphorescent material has only been possible under ultra-high vacuum conditions, where the oxygen partial pressure in the surrounding environment is significantly lower than 1 mmHg. In this regard, the oxygen partial pressure in each tissue in a living body environment often fluctuates within a range of approximately 1 mmHg to 160 mmHg (atmospheric). Furthermore, measuring the oxygen partial pressure in each tissue in a living body is particularly related to the concentration of reactive oxygen species in each tissue. Since the presence or absence of reactive oxygen species in a living body is a factor related to aging, cancer cell growth, and the like, mapping the oxygen partial pressure in a living body environment in the range of 1 mmHg to 160 mmHg is extremely important. Even in light of these circumstances, it has to be said that the techniques based on previous knowledge are lacking in practicality.

[0016] None of the above-mentioned documents report that the behavior of the decay of the phosphorescent intensity over time (afterglow decay) changes depending on the oxygen partial pressure within the oxygen partial pressure range of 1 mmHg or more and 160 mmHg or less, nor does it report any means for bringing about such a change. For example, in the description of Non-Patent Document 4, the oxygen concentration at which the afterglow is detectable is limited to a very low oxygen partial pressure range of 1%, that is, 1.6 mmHg or less. Furthermore, in the description of Non-Patent Document 4, the afterglow persistence time (phosphorescence life) hardly changes at oxygen partial pressures from 0 mmHg to 1.6 mmHg.

[0017] Therefore, an object of the present invention is to provide a method for quickly and simply evaluating oxygen partial pressure within the range of 1 mmHg to 160 mmHg using a phosphorescent material.A further object of the present invention is to provide an apparatus for quickly and simply evaluating a wide range of oxygen partial pressures, including the range of 1 mmHg to 160 mmHg.

[0018] That is, the gist of the present invention is as follows.

[0019] [1] A method for evaluating oxygen partial pressure using phosphorescent particles with an average particle size of 9.56 μm or less, based on differences in the behavior of the phosphorescent particles in terms of attenuation of luminescence intensity over time after irradiation of the excitation light is stopped.

[0020] [2] The method according to [1], wherein the phosphorescent particles used have an average phosphorescent lifetime of 1 ms or more at atmospheric pressure.

[0021] [3] The phosphorescent particles used are represented by the following formula (1): [where p is the oxygen partial pressure in the ambient environment (unit: mmHg), and τ ０ is the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is 0 (mmHg), and τ ｐ is the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is p (mmHg). ｄｉｆｆ But when p = 160 (mmHg), it is 0.00003 mmHg －１ s －１ Over 0.30mmHg －１ s－１ The method according to [1] or [2], which is as follows:

[0022] [4] The method according to any one of [1] to [3], wherein the phosphorescent particles used have crystallinity.

[0023] [5] The method according to any one of [1] to [4], wherein the phosphorescent particle used has a neighboring atom that is the atom closest to an oxygen atom in an oxygen molecule in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby having one surface on which there is a space in which oxygen molecules can be arranged.

[0024] [6] The method according to any one of [1] to [4], wherein the phosphorescent particle used has a neighboring atom that is the atom closest to the oxygen atom in the oxygen molecule in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby having three faces on which there is space in which oxygen molecules can be arranged.

[0025] [7] The phosphorescent particles used have a density of 1.10 g / cm ３ 2.00g / cm or more ３ The method according to any one of [1] to [6] below.

[0026] [8] The method according to any one of [1] to [7], wherein the oxygen partial pressure is evaluated within a range of 1 mmHg or more and 160 mmHg or less.

[0027] [9] The method according to any one of [1] to [8], wherein the surface of the phosphorescent particles used is coated with a polymer.

[0028]

[10] A device for evaluating oxygen partial pressure, comprising: a measurement unit that uses phosphorescent particles having an average particle size of 9.56 μm or less and measures the luminescence intensity of the phosphorescent particles over time after irradiation of the particles with excitation light has stopped; and a control unit that evaluates the oxygen partial pressure based on differences in the behavior of the luminescence intensity attenuated over time measured by the measurement unit.

[0029] According to the present invention, a method for quickly and simply evaluating oxygen partial pressure in the range of 1 mmHg to 160 mmHg using a phosphorescent material can be provided. Also, according to the present invention, a device for quickly and simply evaluating oxygen partial pressure in a wide range including the range of 1 mmHg to 160 mmHg can be provided.

[0030] FIG. 1 is a diagram showing an overview of an apparatus according to an embodiment of the present invention; FIG. 2 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Example 1; FIG. 3 is a diagram showing the relationship between oxygen partial pressure and the reciprocal of the average phosphorescence lifetime in Example 1; FIG. 4 is a diagram showing the relationship between oxygen partial pressure and the average phosphorescence lifetime in Example 1; FIG. 5 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Comparative Example 1; FIG. 6 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Example 2; FIG. 7 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Example 3; FIG. 8 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Example 4; FIG. 9 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Comparative Example 2; FIG. 10 is a diagram showing the behavior of phosphorescence intensity decay over time for each oxygen partial pressure in Example 5; FIG. 11 is a diagram showing the relationship between oxygen partial pressure and the reciprocal of the phosphorescence lifetime in Example 5; FIG. 12 is a diagram showing the relationship between oxygen partial pressure and the phosphorescence lifetime in Example 5. FIG. 1 is a diagram showing the behavior of phosphorescence intensity attenuation over time for each oxygen partial pressure in Example 6. FIG. 2 is a diagram showing the behavior of phosphorescence intensity attenuation over time for each oxygen partial pressure in Comparative Example 3. FIG. 3 is a diagram showing the behavior of phosphorescence intensity attenuation over time for each oxygen partial pressure in Comparative Example 4. FIG. 4 is a diagram showing the behavior of phosphorescence intensity attenuation over time for each oxygen partial pressure in Example 7. FIG. 5 is a diagram showing the behavior of phosphorescence intensity attenuation over time for each oxygen partial pressure in Comparative Example 5. FIG. 6 is a summary of example test data that can actually be obtained using phosphorescent particles.

[0031] The method for evaluating oxygen partial pressure of the present invention will be described below based on embodiments. However, such description is intended to exemplify the present invention and does not limit the present invention in any way.

[0032] (Method for Evaluating Oxygen Partial Pressure) A method for evaluating oxygen partial pressure according to one embodiment of the present invention (hereinafter, sometimes referred to as the "method of this embodiment") uses phosphorescent particles having an average particle size of 9.56 μm or less, and evaluates the oxygen partial pressure based on differences in the behavior of the phosphorescent particles regarding the decay of their luminescence intensity (phosphorescence intensity, phosphorescence intensity) over time after irradiation of the excitation light has stopped.

[0033] The term "luminous particles" refers to particles containing a luminous material. The term "luminous material" refers to a material that exhibits a luminous phenomenon, and is also referred to in the art as a "delayed luminescence material."

[0034] The present inventors have recently discovered that, for materials using molecules exhibiting a phosphorescent phenomenon (afterglow), when the molecules are relatively large, the decay of the afterglow is not affected. However, when the molecules are microparticulated and dispersed in water, the decay of the afterglow, particularly the phosphorescent lifetime, changes in response to a wide range of changes in the oxygen partial pressure in the water. The present invention is based on this new finding, and by using phosphorescent particles with an average particle size of 9.56 μm or less, the decay of the afterglow can be varied in response to a wide range of changes in oxygen partial pressure. Furthermore, by focusing on this difference, the present invention enables rapid and easy evaluation of oxygen partial pressures in the range of 0 mmHg to 160 mmHg, particularly in the range of 1 mmHg to 160 mmHg, which has previously been difficult to evaluate.

[0035] In addition, when the phosphorescent material is a relatively large solid (for example, particle size 10 μm or more) like a bulk, it takes time for oxygen to progress from the surface to the inside even in an environment with a relatively high oxygen partial pressure such as atmospheric pressure (oxygen partial pressure 160 mmHg). Therefore, it can be considered that such phosphorescent materials tend to always show a similar afterglow decay without being significantly dependent on the oxygen partial pressure.

[0036] Furthermore, for example, if the phosphorescent material (usually made of a host material and a guest material) is made of a material into which oxygen can easily penetrate, the afterglow will disappear instantly if oxygen easily penetrates (i.e., the afterglow time after irradiation with excitation light is stopped will be very short). Therefore, it can be considered that simply adjusting the material of the phosphorescent material in this way will not allow the afterglow, and therefore the phosphorescent responsiveness to oxygen partial pressure, to be confirmed unless the material is in an environment where oxygen is extremely unlikely to penetrate, specifically, an ultra-high vacuum where the oxygen partial pressure is sufficiently smaller than 1 mmHg.

[0037] The phenomenon of the afterglow decay changing in response to changes in oxygen partial pressure (phosphorescence response to oxygen partial pressure), which is the focus of the present invention, is thought to be influenced by variations in the size of the phosphorescent material. In this regard, phosphorescent particles with an average particle size of 9.56 μm or less also have a relatively small particle size variation (standard deviation). Therefore, it is thought that this small standard deviation also contributes to solving the problem of the present invention.

[0038] According to the method of this embodiment, it is possible to obtain oxygen partial pressure information of each tissue in a living body environment two-dimensionally and quickly (for example, in about one second) using a solid-state imaging device such as a CCD or CMOS. Therefore, it is possible to perform accurate oxygen partial pressure mapping of a living specimen. The method of this embodiment is not limited to evaluating the oxygen partial pressure (oxygen concentration) of each tissue in a living body environment, but can also be used for oxygen sensors in various fields.

[0039] Next, the method of this embodiment will be specifically described together with preferred embodiments.

[0040] As described above, the average particle size of the phosphorescent particles used in the method of this embodiment is 9.56 μm or less. This upper limit of the average particle size was discovered through extensive experiments by the inventors. In this case, the change in the decay of the afterglow in response to changes in oxygen partial pressure (phosphorescent responsiveness to oxygen partial pressure) can be clearly confirmed. Furthermore, from the viewpoint of making the change in the decay of the afterglow more clear, the average particle size of the phosphorescent particles used in the method of this embodiment is preferably 5.0 μm or less, more preferably 2.0 μm or less, even more preferably 1.0 μm or less, and even more preferably 0.50 μm or less. Furthermore, the lower limit of the average particle size of the phosphorescent particles is not particularly limited, but from a practical viewpoint, it can be set to, for example, 10 nm or more. Note that the method of this embodiment may use only one phosphorescent particle (one particle) (in which case, the term "average particle size" in this specification will be simply read as "particle size").

[0041] The phosphorescent particles used in the method of this embodiment preferably have an average phosphorescent lifetime of 1 ms or more at atmospheric pressure. In this case, the change in the decay of the afterglow in response to changes in oxygen partial pressure (phosphorescent responsiveness to oxygen partial pressure) can be more clearly confirmed. Furthermore, taking into account the readout time of solid-state imaging devices such as CCDs and CMOS, the average phosphorescent lifetime of the phosphorescent particles at atmospheric pressure is more preferably 20 ms or more. The average phosphorescent lifetime can be measured using a two-dimensional photodetector after irradiating and stopping excitation light. The average phosphorescent lifetime can be adjusted by, for example, appropriately selecting the type, crystal structure, composition, size (average particle size), etc. of the phosphorescent material (host material and / or guest material). Furthermore, when only one phosphorescent particle (one particle) is used, the term "average phosphorescent lifetime" in this specification can be simply read as "phosphorescent lifetime."

[0042] The phosphorescent particles used in the method of this embodiment are represented by the following formula (1): [where p is the oxygen partial pressure in the ambient environment (unit: mmHg), and τ ０ is the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is 0 (mmHg), and τ ｐis the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is p (mmHg). ｄｉｆｆ (Quenching rate constant of phosphorescence by oxygen) is 0.00003 mmHg when p = 160 (mmHg) －１ s －１ Over 0.30mmHg －１ s －１ The quenching rate constant k of the phosphorescent particles is preferably equal to or less than the above. ｄｉｆｆ is 0.00003 mmHg －１ s －１ If the oxygen partial pressure is 1 mmHg or more and 160 mmHg or less, the decay of the afterglow (phosphorescence response to oxygen partial pressure) can be more reliably changed in response to changes in the oxygen partial pressure in the range of 0 mmHg or more and 160 mmHg or less. ｄｉｆｆ is 0.30 mmHg －１ s －１ If k is less than 1 / 2, measurement can be performed using only a two-dimensional photodetector even in an environment with a relatively high oxygen partial pressure, such as atmospheric pressure (oxygen partial pressure 160 mmHg). ｄｉｆｆ is 0.0001 mmHg －１ s －１ More preferably, 0.20 mmHg or more －１ s －１ More preferably, it is:

[0043] The oxygen partial pressure p of the environment surrounding the particles (for example, the oxygen partial pressure in the aqueous solution in which the particles are dispersed) can be measured using a commercially available oxygen meter. ０ can be confirmed by measuring the phosphorescence lifetime of the particles in an oxygen-free environment. ｐ can be determined by measuring the phosphorescence lifetime of the particles in an environment with an oxygen partial pressure p (for example, by dispersing the particles in an aqueous solution with an oxygen partial pressure p). ０ and τ ｐ By substituting into equation (1), k ｄｉｆｆ can be determined.

[0044] extinction rate constant k ｄｉｆｆcan be adjusted by, for example, appropriately selecting the type, crystal structure, composition, size (average particle size), etc. of the phosphorescent material (host material and / or guest material).

[0045] The light-storing material that constitutes the light-storing particles used in the method of this embodiment may be an inorganic compound or an organic compound.

[0046] The light-storing particles used in the method of this embodiment are preferably crystalline. In this case, the quenching rate constant k ｄｉｆｆ This makes it possible to more reliably bring about a change in the decay of the afterglow in response to a change in the oxygen partial pressure (phosphorescence responsiveness to the oxygen partial pressure).

[0047] The phosphorescent particles used in the method of this embodiment, particularly when crystalline, preferably have a neighboring atom that is the atom closest to the oxygen atom in oxygen molecules in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby providing one surface with a space in which oxygen molecules can be arranged. In this case, at atmospheric pressure (oxygen partial pressure of 160 mmHg), oxygen can reach the center of the particle in a short time after excitation light irradiation is stopped, depending on the size of the space. As a result, the phosphorescence decay time can be gradually changed over a wide oxygen partial pressure range from 0 mmHg to 160 mmHg. In this case, the space in the phosphorescent particle is sometimes referred to as a "one-dimensional oxygen permeation space."

[0048] Alternatively, the phosphorescent particles used in the method of this embodiment, particularly when crystalline, preferably have a neighboring atom that is the atom closest to the oxygen atom in the oxygen molecule in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby providing three surfaces with spaces in which oxygen molecules can be arranged. In this case, at atmospheric pressure (oxygen partial pressure of 160 mmHg), oxygen can reach the vicinity of the particle center in a short time after the excitation light irradiation is stopped, depending on the size of the spaces. As a result, the phosphorescence decay time can be gradually changed over a wide oxygen partial pressure range from 0 mmHg to 160 mmHg. Furthermore, in this case, even when the density is relatively low, the quenching rate constant k ｄｉｆｆ The value of can be reduced, and the quenching rate constant k ｄｉｆｆ This has the effect of bringing the value of into a more appropriate range. In this case, the space in the phosphorescent particles is sometimes referred to as a "three-dimensional oxygen permeable space."

[0049] The planes where the spaces for arranging the oxygen molecules are present can be identified by X-ray single crystal structure analysis of the host material. More specifically, the crystal structure is determined by X-ray single crystal structure analysis, and the atomic conformations are observed from the a-b plane, the bc plane, and the ac plane along the a-axis, the b-axis, and the c-axis in the crystal structure.

[0050] The phosphorescent particles used in the method of this embodiment have a density of 1.10 g / cm ３ 2.00g / cm or more ３ If the density of the phosphorescent particles is within the above range, the quenching rate constant k ｄｉｆｆ This makes it possible to more reliably bring about a change in the decay of the afterglow in response to a change in the oxygen partial pressure (luminescence response to the oxygen partial pressure). ３ From the same viewpoint, the density of the phosphorescent particles used in the method of this embodiment is 1.11 g / cm ３More preferably, it is 1.50 g / cm or more. ３ More preferably, it is:

[0051] The density of the phosphorescent particles can be determined by X-ray single crystal structure analysis of the host material. More specifically, the crystal structure is determined by X-ray single crystal structure analysis, and the density can be determined from the volume and mass of the unit cell of the crystal structure.

[0052] The light-storing material constituting the light-storing particles used in the method of this embodiment is generally composed of a host material and a guest material.

[0053] The host material is not particularly limited, and examples thereof include H ８ -BINAP-based molecules; benzophenone-based molecules; etc. ８ Examples of the BINAP-based molecules include (S)-(-)-2,2'-bis(diphenylphosphino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl ((S)-H ８ -BINAP); (R)-(+)-2,2'-bis(diphenylphosphino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl ((R)-H ８ -BINAP); and the like. Examples of the benzophenone-based molecules include 4,4'-di-tert-butylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-dibromobenzophenone. These host materials may be used singly or in combination of two or more.

[0054] The guest material is not particularly limited, and examples thereof include BINAP-based molecules; benzochrysene-based molecules; and the like. Examples of the BINAP-based molecules include (S)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ((S)-BINAP); (R)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ((R)-BINAP); deuterated versions thereof; and the like. Examples of the benzochrysene-based molecules include benzo[g,p]chrysene; deuterated versions thereof; and the like. These guest materials may be used alone or in combination of two or more. In particular, when benzophenone-based molecules are used as the host material, various guest materials other than those described above may be used as the guest material.

[0055] Regarding the host material and the guest material, any of the host materials described above can be used in combination with any of the guest materials described above. In this case, the combination of the host material and the guest material is determined based on the quenching rate constant k of the light-storing particles formed. ｄｉｆｆ The thickness can be appropriately selected based on the viewpoints of the oxygen permeation space, density, etc.

[0056] The mass ratio of the host material and the guest material constituting the phosphorescent particles is not particularly limited. For example, the mass ratio of the guest material to the total mass of the host material and the guest material can be 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 3% by mass or more, 5% by mass or more, 10% by mass or more, or 20% by mass or more, and can be 40% by mass or less, 35% by mass or less, or 30% by mass or less.

[0057] Specifically, evaluation of oxygen partial pressure based on the method of this embodiment can be carried out as follows. That is, relational data (e.g., a calibration curve) is obtained in advance between the oxygen partial pressure (oxygen concentration) and the behavior of the attenuation of luminescence intensity over time after the irradiation of excitation light on the phosphorescent particles under that oxygen partial pressure is stopped. Next, phosphorescent particles are actually placed at the target location where the oxygen partial pressure is to be evaluated, and the phosphorescent particles are irradiated with excitation light, and the irradiation is stopped. At this time, the luminescence intensity over time after the irradiation is stopped is measured. Then, the behavior of the measured attenuation of luminescence intensity is compared with the previously obtained relational data, thereby enabling the oxygen partial pressure of the target location to be evaluated.

[0058] The "behavior related to attenuation of luminous intensity" to be checked against the relational data is not particularly limited, but examples include the phosphorescence life or average phosphorescence life.

[0059] When evaluating oxygen partial pressure using the method of this embodiment, the phosphorescent particles can be dispersed in a dispersion liquid such as water and used, or they can be used as they are. When using phosphorescent particles dispersed in a dispersion liquid, it is preferable that the surfaces of the phosphorescent particles are coated with a polymer. This can suppress aggregation in the dispersion liquid, and the change in the decay of the afterglow in response to changes in oxygen partial pressure (phosphorescence response to oxygen partial pressure) can be more clearly observed. The polymer that coats the surface is not particularly limited, and examples thereof include block copolymers having monomer units of hydrophilic and hydrophobic parts, and more specifically, examples thereof include copolymers of ethylene glycol and propylene glycol. On the other hand, when using phosphorescent particles as they are, the phosphorescent particles can be directly sprayed onto the target area where the oxygen partial pressure is to be evaluated.

[0060] FIG. 17 shows an example of test data that can be obtained using actual phosphorescent particles. To obtain this test data, for example, phosphorescent particles are dispersed in a dispersion liquid such as water. At the start of the test, nitrogen is bubbled through the dispersion liquid, and the oxygen partial pressure in the dispersion liquid is substantially 0 mmHg. From this state, excitation light is irradiated, and the irradiation is stopped after a certain period of time (section A in FIG. 17 ). Next, the phosphorescence intensity of the phosphorescent particles immediately after the irradiation is stopped is measured over time (section B in FIG. 17 ). Next, oxygen is introduced into the dispersion liquid by stopping the nitrogen bubbling (oxygen partial pressure: 160 mmHg), and excitation light is irradiated again, and the irradiation is stopped after a certain period of time (section C in FIG. 17 ). Next, the phosphorescence intensity of the phosphorescent particles immediately after the irradiation is stopped is measured over time (section D in FIG. 17 ). Next, nitrogen bubbling is resumed (oxygen partial pressure: essentially 0 mmHg), and excitation light is irradiated again. After a certain time has elapsed, irradiation is stopped (section E in FIG. 17). The same operation is then repeated (sections F, G, and H in FIG. 17). Looking at the phosphorescence intensity over time in the sections where the phosphorescence intensity is measured over time, i.e., sections B, D, F, and H in FIG. 17, the sections where nitrogen bubbling is not performed (D, H) decay more rapidly (the decay slope is steeper) than the sections where nitrogen bubbling is performed (B, F). In this way, the phosphorescent response to oxygen partial pressure can be easily confirmed.

[0061] Furthermore, the method of this embodiment has the following exceptional advantages: it is possible to confirm changes in oxygen partial pressure even over short time intervals (for example, even over 2 to 3 seconds as shown in FIG. 17); the behavior of changes in the luminescence intensity of the phosphorescent particles is stable, resulting in high reproducibility; and it is also possible to perform detection using a two-dimensional image of a fixed point, as shown in the upper part of FIG. 17. These applications make it possible to obtain changes in decay two-dimensionally.

[0062] (Device for Evaluating Oxygen Partial Pressure) An apparatus according to one embodiment of the present invention (hereinafter sometimes referred to as the "device of this embodiment") is an apparatus for evaluating oxygen partial pressure. The device of this embodiment is characterized by including at least a measurement unit that uses phosphorescent particles having an average particle size of 9.56 μm or less and measures the luminescence intensity of the phosphorescent particles over time after irradiation with excitation light has stopped, and a control unit that evaluates the oxygen partial pressure based on differences in the behavior of the luminescence intensity attenuated over time measured by the measurement unit. The device of this embodiment can quickly and easily evaluate the oxygen partial pressure at a target location. Furthermore, the evaluation range of this oxygen partial pressure is wide, including a range of 1 mmHg or more and 160 mmHg or less.

[0063] The device of this embodiment basically functions based on the above-described method for evaluating oxygen partial pressure, and can be used to evaluate the oxygen partial pressure (oxygen concentration) in various target locations, including various tissues in a living body environment.

[0064] An overview of the device of this embodiment is shown in Figure 1. The device of this embodiment includes a measurement unit 11, a control unit 12, and a notification unit 13. The control unit 12 is electrically connected to the measurement unit 11 and the notification unit 13.

[0065] In the device of this embodiment, the measurement unit 11 uses phosphorescent particles with an average particle size of 9.56 μm or less and has the function of measuring the luminescence intensity of the phosphorescent particles over time after irradiation with excitation light has stopped. During such measurement, the phosphorescent particles are placed at the target location for evaluating the oxygen partial pressure, and the luminescence intensity over time can be measured. Note that the phosphorescent particles may be placed at the target location of the measurement unit 11 each time a measurement is performed, or may be placed at a predetermined target location all the time. The measurement unit 11 may be composed of, for example, a sensor.

[0066] The details and preferred embodiments of the phosphorescent particles themselves are the same as those of the phosphorescent particles described in relation to the method for evaluating oxygen partial pressure.

[0067] In the device of this embodiment, the control unit 12 has a function of evaluating the oxygen partial pressure based on differences in the behavior of the decay of luminescence intensity over time measured by the measurement unit 11. This control unit 12 can be configured to store in advance relationship data (e.g., a calibration curve such as that shown in FIG. 3A or relationship data such as that shown in FIG. 3B according to an example described below) between the oxygen partial pressure and the behavior of the decay of luminescence intensity over time after irradiation of the light-storing particles with excitation light has stopped (e.g., the light-storing life, the average light-storing life, etc.). The control unit 12 can evaluate (output) the oxygen partial pressure of the target location by comparing the behavior of the decay of luminescence intensity over time actually measured by the measurement unit 11 (e.g., the light-storing life, the average light-storing life, etc.) with the relationship data.

[0068] In the device of this embodiment, the notification unit 13 has a function of notifying the user of the evaluation information of the control unit 12. The notification unit 13 can notify the user of the evaluation information by, for example, visual information (e.g., video, still images, text information, etc.) or sound, etc. The notification unit 13 may be configured, for example, by a display or a speaker, etc.

[0069] The device of this embodiment may further include a calibration unit (not shown) that can appropriately calibrate the relationship data stored in the control unit 12 .

[0070] The control unit 12 and / or the calibration unit can also be realized by a computer program. For example, a computer reading device reads a program for realizing the functions of the control unit 12 and / or the calibration unit from a recording medium on which the program is recorded, and stores the program in a storage device. The CPU then copies the program stored in the storage device to RAM, and sequentially reads and executes instructions included in the program from RAM, thereby realizing the functions of the control unit 12 and / or the calibration unit.

[0071] The present invention will be described in more detail below with reference to examples. However, these examples are intended to illustrate the present invention and are not intended to limit the present invention in any way.

[0072] Example 1 Powder of (S)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ((S)-BINAP) (manufactured by Wako Chemical Industries, Ltd.) was dissolved in water to obtain (S)-(-)-2,2'-bis(diphenylphosphino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl ((S)-H ８ (S)-BINAP (Sigma-Aldrich) powder was mixed with (S)-BINAP powder to obtain a mixed powder. The mixed powder was adjusted so that the concentration of (S)-BINAP powder was 10% by mass. (S)-BINAP was used as a guest material in the phosphorescent material, and (S)-H ８ The mixed powder was then heated to 240°C on a glass substrate and melted. The glass substrate was then transferred to a hot plate heated to 160°C, which is higher than the glass transition temperature, and heated until the entire mixture was crystalline, producing a crystalline mixture (10% by mass (S)-BINAP / 90% by mass (S)-H) as the light-storing material A. ８ A film of ZnO-BINAP crystals was prepared.

[0073] Meanwhile, Eosin Y (manufactured by Tokyo Chemical Industry Co., Ltd.) (used for the purpose of determining the oxygen partial pressure later) and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (F127) (manufactured by Sigma-Aldrich) (used for the purpose of coating the particle surfaces) were dissolved in pure water to obtain an aqueous solution. The aqueous solution was adjusted so that the concentration of Eosin Y was 6.13 mol / L and the concentration of F127 was 3.33 g / L. Next, the luminescent material A prepared as described above was dispersed in this aqueous solution to a concentration of 3.33 g / L, and ultrasonic treatment was performed for 10 minutes. This resulted in an aqueous dispersion in which the luminescent material A was crushed and dispersed as particles (luminescent particles).

[0074] The resulting aqueous dispersion was then quickly filtered using a membrane filter with a pore size of 0.45 μm, and the filtrate was obtained as sample aqueous solution 1. In short, this sample aqueous solution 1 contains particles of luminous material A (luminous particles) having an average particle size of 0.45 μm or less.

[0075] The phosphorescent particles have a quenching rate constant k at an oxygen partial pressure of 160 mmHg. ｄｉｆｆ is 0.021 mmHg －１ s －１ The phosphorescent particles have a "three-dimensional oxygen permeable space" and a density of 1.20 g / cm ３ It was as follows.

[0076] Next, sample aqueous solution 1 was placed in a quartz cell with a rubber lid, and nitrogen gas was introduced into the quartz cell to thoroughly remove oxygen (the oxygen partial pressure in sample aqueous solution 1 was set to substantially 0 mmHg). Then, using a fluorescence spectrophotometer (JASCO Corporation, FP-8300), 360 nm excitation light was irradiated immediately after irradiation was stopped, and the average phosphorescence lifetime at a wavelength of 510 nm for the phosphorescence from the phosphorescent particles was measured, which was measured to be 279 ms. The wavelength of 510 nm roughly corresponds to the peak wavelength in the phosphorescence spectrum of phosphorescent material A. Furthermore, the phosphorescence intensity of the phosphorescence from the phosphorescent particles immediately after irradiation was stopped was measured over time, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 2.

[0077] Next, to slightly increase the oxygen partial pressure in Sample Aqueous Solution 1, the quartz cell container was opened and exposed to the atmosphere for a very short time, and then immediately closed. In this state, the transient absorption decay signal of eosin Y contained in Sample Aqueous Solution 1 was measured using a transient absorption spectrometer (PicoTAS, manufactured by UNISOKU Co., Ltd.) to determine the oxygen partial pressure, which was 20 mmHg. Immediately after this, excitation light of 360 nm was irradiated in the same manner as above, and the average phosphorescence lifetime at a wavelength of 510 nm for the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped was measured, which was measured to be 178 ms. Furthermore, the phosphorescence intensity of the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped was measured over time, as described above, to confirm the behavior (decay) of the phosphorescence intensity over time. The results are shown in Figure 2.

[0078] Next, to further slightly increase the oxygen partial pressure in Sample Aqueous Solution 1, the quartz cell container was opened for a very short time, exposed to the atmosphere, and then immediately closed. In this state, the transient absorption decay signal of eosin Y contained in Sample Aqueous Solution 1 was measured in the same manner as above to determine the oxygen partial pressure, which was 66 mmHg. Immediately thereafter, excitation light of 360 nm was irradiated in the same manner as above, and the average phosphorescence lifetime at a wavelength of 510 nm was measured for the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped, which was measured to be 102 ms. Furthermore, the phosphorescence intensity of the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped was measured over time in the same manner as above, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 2.

[0079] Next, to further increase the oxygen partial pressure in Sample Aqueous Solution 1 slightly, the quartz cell container was opened for a very short time, exposed to the atmosphere, and then immediately closed. In this state, the transient absorption decay signal of eosin Y contained in Sample Aqueous Solution 1 was measured in the same manner as above to determine the oxygen partial pressure, which was 131 mmHg. Immediately thereafter, excitation light of 360 nm was irradiated in the same manner as above, and the average phosphorescence lifetime at a wavelength of 510 nm was measured for the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped, which was measured to be 77 ms. Furthermore, the phosphorescence intensity of the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped was measured over time, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 2.

[0080] Finally, the quartz cell container was opened and exposed to the atmosphere for a long period of time, until the oxygen partial pressure in the sample aqueous solution 1 was equivalent to atmospheric pressure (160 mmHg). Then, in the same manner as above, 360 nm excitation light was irradiated, and the average phosphorescence lifetime at a wavelength of 510 nm was measured for the phosphorescence from the phosphorescent particles immediately after the irradiation was stopped, and it was measured to be 68 ms. Furthermore, in the same manner as above, the phosphorescence intensity from the phosphorescent particles immediately after the irradiation was stopped was measured over time, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 2.

[0081] Figure 3A shows the relationship between the oxygen partial pressure and the reciprocal of the average phosphorescence lifetime based on the above measurements for sample aqueous solution 1 containing particles of phosphorescent material A with an average particle size of 0.45 μm or less. Here, the average phosphorescence lifetime was determined by fitting each decay in Figure 2 with a double exponential function. Figure 3A shows that there is an approximately linear relationship. Figure 3B also shows a graph (relational data) in which the straight line (calibration curve) shown in Figure 3A is converted into the relationship between oxygen partial pressure and average phosphorescence lifetime.

[0082] From FIG. 2, it can be seen that in the sample aqueous solution 1 containing particles of the luminescent material A with an average particle size of 0.45 μm or less, the degree (speed) of decay of the phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0083] According to the above Example 1 ( FIG. 3B ), it can be seen that by using a phosphorescent material having an average phosphorescence lifetime of 50 ms or more, oxygen partial pressures in the range of 1 mmHg or more and 160 mmHg or less can be quickly and easily evaluated (quantified) based on differences in the behavior (decay) of attenuation of luminescence intensity (phosphorescence intensity) over time.

[0084] (Comparative Example 1) The crystal (10% by mass (S)-BINAP / 90% by mass (S)-H) was used as the phosphorescent material A prepared in Example 1. ８ The luminous material A (BINAP crystals) was dispersed in the form of clumps (without crushing) in an aqueous solution to obtain sample aqueous solution 2. This sample aqueous solution 2 is essentially a suspension of clumps of luminous material A (luminous clumps).

[0085] The oxygen partial pressure in sample aqueous solution 2 was set to a state equivalent to atmospheric pressure (160 mmHg). Then, using a fluorescence spectrophotometer (JASCO Corporation, FP-8300), 360 nm excitation light was irradiated, and the average phosphorescence lifetime at a wavelength of 510 nm was measured for the phosphorescence from the phosphorescent block immediately after irradiation was stopped, and it was measured to be 0.52 s. Furthermore, in the same manner as above, the phosphorescence intensity from the phosphorescent block immediately after irradiation was stopped was measured over time, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 4.

[0086] Nitrogen bubbling was performed on the sample aqueous solution 2 placed in the container, and the container was immediately sealed (the oxygen partial pressure in the sample aqueous solution 2 was set to substantially 0 mmHg). Then, in the same manner as above, 360 nm excitation light was irradiated without any time delay, and the average phosphorescence lifetime at a wavelength of 510 nm was measured for the phosphorescence from the phosphorescent block immediately after the irradiation was stopped, and it was measured to be 0.52 s. Furthermore, the phosphorescence intensity of the phosphorescence from the phosphorescent block immediately after the irradiation was stopped was measured over time, and the behavior (decay) of the phosphorescence intensity attenuated over time was confirmed. The results are shown in Figure 4.

[0087] According to the above measurements, for the aqueous sample solution 2 in which the lumps of the luminescent material A were suspended, almost no difference in the average phosphorescence lifetime was observed even when the oxygen partial pressure was changed.

[0088] Furthermore, as can be seen from FIG. 4, in the sample aqueous solution 2 in which the lumps of luminescent material A were suspended, the behavior of the decay of phosphorescence intensity over time showed almost no difference depending on the oxygen partial pressure.

[0089] Example 2 Deuterated dibenzo[g,p]chrysene (DBC-d １６ The powder of DBC-d was mixed with the powder of 4,4'-di-tert-butylbenzophenone (t-Bu-BP) (manufactured by Tokyo Chemical Industry Co., Ltd.) to obtain a mixed powder. １６ The concentration of the powder was adjusted to 0.3% by mass. １６ was used as a guest material in the phosphorescent material, and t-Bu-BP was used as a host material in the phosphorescent material. Next, this mixed powder was heated to 150°C on a glass substrate and melted. Next, the glass substrate was returned to room temperature, and a crystal (0.3 mass% DBC-d １６ A film of t-Bu-BP (99.7 mass % t-Bu-BP crystal) was prepared.

[0090] On the other hand, F127 was dissolved in pure water to a concentration of 3.33 g / L to obtain an aqueous solution. Next, the luminescent material B prepared as described above was dispersed in this aqueous solution to a concentration of 3.33 g / L, and ultrasonic treatment was performed for 10 minutes. This resulted in an aqueous dispersion in which the luminescent material B was crushed and dispersed as particles (luminescent particles).

[0091] The resulting aqueous dispersion was then quickly filtered using a membrane filter with a pore size of 0.45 μm, and the filtrate was obtained as sample aqueous solution 3. In short, this sample aqueous solution 3 contains particles of luminous material B (luminous particles) having an average particle size of 0.45 μm or less.

[0092] The phosphorescent particles have a quenching rate constant k at an oxygen partial pressure of 160 mmHg. ｄｉｆｆ is 0.0209 mmHg －１ s －１ The phosphorescent particles have a one-dimensional oxygen permeable space and a density of 1.11 g / cm ３ It was as follows.

[0093] The oxygen partial pressure in sample aqueous solution 3 was set to a state equivalent to atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 5. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.36 s. The wavelength of 610 nm roughly corresponds to the peak wavelength in the phosphorescence spectrum of phosphorescent material B.

[0094] Nitrogen bubbling was performed on the sample aqueous solution 3 placed in the container, and immediately thereafter the container was kept sealed (the oxygen partial pressure in the sample aqueous solution 3 was set to substantially 0 mmHg). Then, in the same manner as above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 5. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 2.1 s.

[0095] The above measurements show that for the aqueous sample solution 3 containing particles of the luminescent material B with an average particle size of 0.45 μm or less, the average phosphorescence lifetime tends to be shorter as the oxygen partial pressure increases.

[0096] Furthermore, from FIG. 5, it can be seen that in the sample aqueous solution 3 containing particles of the luminescent material B having an average particle size of 0.45 μm or less, the degree (speed) of decay of the phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0097] Example 3 A sample aqueous solution 4 was obtained in the same manner as in Example 2, except that a membrane filter with a pore size of 2.0 μm was used instead of the membrane filter with a pore size of 0.45 μm in Example 2. In short, this sample aqueous solution 4 contains particles of luminous material B (luminous particles) with an average particle size of 2.0 μm or less.

[0098] The phosphorescent particles have a one-dimensional oxygen permeable space and a density of 1.11 g / cm ３ It was as follows.

[0099] The oxygen partial pressure in the sample aqueous solution 4 was adjusted to a state equivalent to atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 6. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.45 s.

[0100] Nitrogen bubbling was performed on the aqueous sample solution 4 placed in the container, and the container was immediately kept sealed (the oxygen partial pressure in the aqueous sample solution 4 was set to substantially 0 mmHg). Then, in the same manner as described above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 6. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 2.1 s.

[0101] The above measurements show that for sample aqueous solution 4 containing particles of luminescent material B with an average particle size of 2.0 μm or less, the average phosphorescence lifetime tends to shorten as the oxygen partial pressure increases.

[0102] Furthermore, from FIG. 6, it can be seen that in the sample aqueous solution 4 containing particles of the luminescent material B having an average particle size of 2.0 μm or less, the degree (speed) of decay of the phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0103] Example 4 A sample aqueous solution 5 was obtained in the same manner as in Example 2, except that a membrane filter with a pore size of 5.0 μm was used instead of the membrane filter with a pore size of 0.45 μm in Example 2. In short, this sample aqueous solution 5 contains particles of luminous material B (luminous particles) with an average particle size of 9.56 μm or less.

[0104] The phosphorescent particles have a one-dimensional oxygen permeable space and a density of 1.11 g / cm ３ It was as follows.

[0105] The oxygen partial pressure in the sample aqueous solution 5 was adjusted to a state equivalent to atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 7. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.48 s.

[0106] Nitrogen bubbling was performed on the aqueous sample solution 5 placed in the container, and the container was immediately sealed (the oxygen partial pressure in the aqueous sample solution 5 was set to substantially 0 mmHg). Then, in the same manner as described above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 7. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 2.1 s.

[0107] The above measurements show that for the aqueous sample solution 5 containing particles of the luminescent material B with an average particle size of 9.56 μm or less, the average phosphorescence lifetime tends to be shorter as the oxygen partial pressure increases.

[0108] Furthermore, from FIG. 7, it can be seen that in the sample aqueous solution 5 containing particles of the luminescent material B having an average particle size of 9.56 μm or less, the degree (speed) of decay of the phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0109] According to the above Examples 2 to 4, it can be seen that by using a phosphorescent material having an average phosphorescence lifetime of 100 ms or more, oxygen partial pressures in the range of 1 mmHg or more and 160 mmHg or less can be quickly and simply evaluated (quantified) based on differences in the behavior (decay) of attenuation of luminescence intensity (phosphorescence intensity) over time.

[0110] (Comparative Example 2) The crystal (0.3 mass % DBC-d １６ / 99.7 mass% t-Bu-BP crystals) was dispersed as a lump (without crushing) in an aqueous solution to obtain sample aqueous solution 6. In short, this sample aqueous solution 6 contains suspended agglomerates of luminous material B (luminous agglomerates).

[0111] Furthermore, the sample aqueous solution 6 placed in the container was freeze-dried and immediately maintained in a sealed state (the oxygen partial pressure in the sample aqueous solution 6 was set to substantially 0 mmHg). Then, in the same manner as described above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent block was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 8. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function and was measured to be 2.1 s.

[0112] The sealed state of the sample aqueous solution 6 was then released, and the oxygen partial pressure was adjusted to the same level as atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent block was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 8. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 2.0 s.

[0113] According to the above measurements, for the aqueous sample solution 6 in which the lumps of luminescent material B were suspended, almost no difference was observed in the average phosphorescence lifetime even when the oxygen partial pressure was changed.

[0114] Furthermore, as can be seen from FIG. 8, in the sample aqueous solution 6 in which the lumps of luminescent material B were suspended, the behavior of the decay of phosphorescence intensity over time showed almost no difference depending on the oxygen partial pressure.

[0115] Example 5 (R)-[1,1'-binaphthalene]-2,2'-diylbis[1,1-diphenyl-1,1'-phosphine oxide] ((R)-BINAPO) (101 mg), palladium-activated carbon (Pd: 10% by mass) (125 mg), and heavy water (99.8% D) (25 mL) were placed in a well-dried reaction vessel and reacted at 250°C for 12 hours in an electric furnace (AS ONE Corporation, "MMF-1"). The mixture was separated into ethyl acetate and pure water, and the residual carbon was removed by suction filtration. Subsequently, the mixture was purified by column chromatography to obtain (R)-BINAPO-d ３２(34 mg) was obtained. 1,1,3,3-tetramethyldisiloxane (TMDS), tetraisopropyl orthotitanate (Ti(OiPr) ４ ) was bubbled with nitrogen for 30 minutes. ３２ (27.5 mg), TMDS (0.23 mL), tetraisopropyl orthotitanate (0.02 mL), and toluene (0.25 mL) were added and reacted at 80°C for 27 hours under a nitrogen atmosphere. TMDS (0.2 mL) was added and the reaction was continued for an additional 20 hours. The mixture was separated into ethyl acetate and purified water, and purified by column chromatography to obtain deuterated (R)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ((R)-BINAP-d ３２ ) (6 mg) was obtained.

[0116] (R)-BINAP-d ３２ powder of (R)-(+)-2,2'-bis(diphenylphosphino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl ((R)-H ８ The powder was mixed with (R)-BINAP-d (Sigma-Aldrich) powder to obtain a mixed powder. ３２ The concentration of the powder was adjusted to 10% by mass. ３２ is used as a guest material in a phosphorescent material, and (R)-H ８ The mixed powder was then heated to 240°C on a glass substrate and melted. The glass substrate was then transferred to a hot plate heated to 160°C, which is higher than the glass transition temperature, and heated until the entire mixture was crystalline, thereby obtaining a crystalline (10% by mass (R)-BINAP-d ３２ / 90% by mass (R)-H ８ A film of ZnO-BINAP crystals was prepared.

[0117] Meanwhile, F127 (manufactured by Sigma-Aldrich) (used for the purpose of coating the particle surfaces) was dissolved in pure water to obtain an aqueous solution. At this time, the aqueous solution was adjusted so that the concentration of F127 was 3.33 g / L. Next, the luminescent material C prepared as described above was dispersed in this aqueous solution to a concentration of 3.33 g / L, and ultrasonic treatment was performed for 10 minutes. As a result, an aqueous dispersion was obtained in which the luminescent material C was crushed and dispersed as particles (luminescent particles).

[0118] This aqueous solution was diluted with water and applied to a glass substrate. Next, as specifically described below, 360 nm excitation light was irradiated while a mixed gas of oxygen gas and nitrogen gas was flowing, and the behavior (decay) of the phosphorescence intensity over time was observed for the phosphorescence from each individual phosphorescent particle immediately after the irradiation was stopped. The oxygen partial pressure was adjusted by changing the mixture ratio of nitrogen gas and oxygen gas, and was measured with an oxygen meter ("XP-3080" manufactured by New Cosmos Electric Co., Ltd.).

[0119] Two-dimensional Gaussian fitting was performed on the two-dimensional pattern of the emission observed under 360 nm excitation light. As a result, the variance (σ 2 ) is 0.0365 μm ２ The particle size was defined as 6σ, and R was determined to be 1.15 μm. For these particles with R = 1.15 μm, the decay behavior of the phosphorescence intensity over time was confirmed when the oxygen partial pressure was 0 mmHg. The results are shown in FIG. 9. The decay was also fitted with a double exponential function to calculate the phosphorescence lifetime, which was 0.70 s.

[0120] Next, for the particles of R = 1.15 μm, the oxygen partial pressure in the atmosphere (160 mmHg; [O ２ The decay behavior (decay) of the phosphorescence intensity over time was confirmed at an oxygen partial pressure of 160 mmHg (corresponding to ] = 0.0094 mol / L). The results are shown in Figure 9. The decay was also fitted with a double exponential function to calculate the phosphorescence lifetime, which was 0.10 s. The quenching rate constant k of the phosphorescent particles at an oxygen partial pressure of 160 mmHg was also calculated. ｄｉｆｆ is 0.054 mmHg－１ s －１ It was.

[0121] Next, for the particles of R = 1.15 μm, an oxygen partial pressure of 38 mmHg ([O ２ The decay behavior (decay) of the phosphorescence intensity over time was confirmed at an oxygen partial pressure of 38 mmHg. The results are shown in Figure 9. The decay was also fitted with a double exponential function to calculate the phosphorescence lifetime, which was 0.25 seconds. The quenching rate constant k of the phosphorescent particles at an oxygen partial pressure of 38 mmHg was also calculated. ｄｉｆｆ is 0.056 mmHg －１ s －１ It was.

[0122] Next, for the particles of R = 1.15 μm, the oxygen partial pressure is 7.6 mmHg ([O ２ The decay behavior (decay) of the phosphorescence intensity over time was confirmed at an oxygen partial pressure of 7.6 mmHg (corresponding to ] = 0.00045 mol / L). The results are shown in Figure 9. The decay was also fitted with a double exponential function to calculate the phosphorescence lifetime, which was 0.50 s. The quenching rate constant k of the phosphorescent particles at an oxygen partial pressure of 7.6 mmHg was also calculated. ｄｉｆｆ is 0.075 mmHg －１ s －１ It was.

[0123] FIG. 10 is a plot (Stan-Balmer plot) of the reciprocal of oxygen partial pressure and phosphorescence lifetime for particles of phosphorescent material C with R = 1.15 μm. The linear relationship confirmed indicates that a wide range of oxygen partial pressures, from 1 mmHg to 160 mmHg, can be quantitatively evaluated using phosphorescence lifetime. FIG. 11 is a graph (relational data) that converts the straight line (calibration curve) shown in FIG. 10 into a relationship between phosphorescence lifetime and oxygen partial pressure. From this graph, it can be seen that quantitative measurement can be performed using the phosphorescence decay of 0.02 seconds or more after the excitation light irradiation is stopped.

[0124] Example 6: The crystal (10% by mass (S)-BINAP / 90% by mass (S)-H) was used as the phosphorescent material A prepared in Example 1. ８ -BINAP crystals) was crushed in a conventional manner to obtain particles (luminescent particles).

[0125] The particle size of each phosphorescent particle was 9.56 μm. The phosphorescent particles had a quenching rate constant k ｄｉｆｆ is 0.0023 mmHg －１ s －１ The phosphorescent particles have a one-dimensional oxygen permeable space and a density of 1.27 g / cm ３ It was as follows.

[0126] The decay behavior of the phosphorescence intensity over time of the above phosphorescent particles (one phosphorescent particle) was confirmed when the oxygen partial pressure was 160 mmHg and when the oxygen partial pressure was substantially 0 mmHg. The results are shown in Figure 12.

[0127] 12 shows that the average phosphorescence lifetime of the phosphorescent particles of this example tends to shorten as the oxygen partial pressure increases. Furthermore, Fig. 12 also shows that the degree (speed) of decay of phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0128] (Comparative Example 3) The crystal (10% by mass (S)-BINAP / 90% by mass (S)-H) was used as the phosphorescent material A prepared in Example 1. ８ -BINAP crystals) was crushed in a conventional manner to obtain particles (luminescent particles).

[0129] The phosphorescent particles (each phosphorescent particle) had an average particle size of approximately 10 to 15 μm. The decay behavior of the phosphorescence intensity over time for each phosphorescent particle (each phosphorescent particle) was examined when the oxygen partial pressure was 160 mmHg and when the oxygen partial pressure was substantially 0 mmHg. The results are shown in FIG. 13.

[0130] As can be seen from Figure 13, for the phosphorescent particles of this example, almost no difference was observed in the average phosphorescence lifetime despite changes in oxygen partial pressure. Also, as can be seen from Figure 13, for the phosphorescent particles of this example, almost no difference was observed in the behavior of the decay of phosphorescence intensity over time despite changes in oxygen partial pressure.

[0131] (Comparative Example 4) The crystal (10% by mass (S)-BINAP / 90% by mass (S)-H) was used as the phosphorescent material A prepared in Example 1. ８ -BINAP crystals) was crushed in a conventional manner to obtain particles (luminescent particles).

[0132] The phosphorescent particles (each phosphorescent particle) had an average particle size of approximately 20 μm. The decay behavior of the phosphorescence intensity over time for each phosphorescent particle was examined when the oxygen partial pressure was 160 mmHg and when the oxygen partial pressure was substantially 0 mmHg. The results are shown in FIG. 14 .

[0133] As can be seen from Figure 14, for the phosphorescent particles of this example, almost no difference was observed in the average phosphorescence lifetime despite changes in oxygen partial pressure. Also, as can be seen from Figure 14, for the phosphorescent particles of this example, almost no difference was observed in the behavior of the decay of phosphorescence intensity over time despite changes in oxygen partial pressure.

[0134] Example 7 Deuterated dibenzo[g,p]chrysene (DBC-d １６ The powder of DBC-d was mixed with the powder of 4,4'-dibromobenzophenone (DBBP) (Tokyo Chemical Industry Co., Ltd.) to obtain a mixed powder. １６ The concentration of the powder was adjusted to 0.3% by mass. １６ was used as a guest material in the phosphorescent material, and DBBP was used as a host material in the phosphorescent material. Next, this mixed powder was heated to 200°C on a glass substrate and melted. Next, the glass substrate was returned to room temperature, and a crystal (0.3 mass% DBC-d １６ A film of 99.7% by mass DBBP crystal was prepared.

[0135] On the other hand, F127 was dissolved in pure water to a concentration of 3.33 g / L to obtain an aqueous solution. Next, the luminous material B prepared as described above was dispersed in this aqueous solution to a concentration of 3.33 g / L, and ultrasonic treatment was performed for 10 minutes. As a result, an aqueous dispersion was obtained in which the luminous material D was crushed and dispersed as particles (luminous particles).

[0136] The resulting aqueous dispersion was then quickly filtered using a membrane filter with a pore size of 2.0 μm, and the filtrate was obtained as sample aqueous solution 7. In short, this sample aqueous solution 7 contains particles of luminous material D (luminous particles) having an average particle size of 2.0 μm or less.

[0137] The phosphorescent particles have a quenching rate constant k at an oxygen partial pressure of 160 mmHg. ｄｉｆｆ is 0.0389 mmHg －１ s －１ The phosphorescent particles have a "three-dimensional oxygen permeable space" and a density of 1.96 g / cm ３ It was as follows.

[0138] The oxygen partial pressure in sample aqueous solution 7 was set to a state equivalent to atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in Figure 15. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.135 s. The wavelength of 610 nm roughly corresponds to the peak wavelength in the phosphorescence spectrum of phosphorescent material B.

[0139] Nitrogen bubbling was performed on the aqueous sample solution 7 placed in the container, and the container was immediately sealed (the oxygen partial pressure in the aqueous sample solution 7 was set to substantially 0 mmHg). Then, in the same manner as described above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent particles was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity attenuation over time was confirmed. The results are shown in FIG. 15. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.834 s.

[0140] The above measurements show that for sample aqueous solution 7 containing particles of luminescent material D with an average particle size of 2.0 μm or less, the average phosphorescence lifetime tends to shorten as the oxygen partial pressure increases.

[0141] Furthermore, from FIG. 15, it can be seen that in the sample aqueous solution 7 containing particles of the phosphorescent material D having an average particle size of 2.0 μm or less, the degree (speed) of decay of the phosphorescence intensity over time increases as the oxygen partial pressure increases.

[0142] (Comparative Example 5) The crystal (0.3 mass% DBC-d １６ The luminous material D (99.7% by mass DBBP crystals) was dispersed in its lump form (without being crushed) in an aqueous solution to obtain sample aqueous solution 8. In short, this sample aqueous solution 8 is a suspension of luminous material D (luminous lump).

[0143] In addition, the sample aqueous solution 8 placed in the container was freeze-dried and immediately maintained in a sealed state (the oxygen partial pressure in the sample aqueous solution 8 was set to substantially 0 mmHg). Then, in the same manner as described above, 310 nm excitation light was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent block was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 16. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function and was measured to be 0.46 s.

[0144] The sealed state of the sample aqueous solution 8 was then released, and the oxygen partial pressure was adjusted to a state equivalent to atmospheric pressure (160 mmHg). Then, excitation light of 310 nm was irradiated, and the phosphorescence intensity at a wavelength of 610 nm from the phosphorescent block was measured over time immediately after the irradiation was stopped, and the behavior (decay) of the phosphorescence intensity over time was confirmed. The results are shown in Figure 16. Furthermore, the average phosphorescence lifetime was calculated by fitting with a double exponential function, and was measured to be 0.46 s.

[0145] According to the above measurements, for the aqueous sample solution 8 in which the lumps of the luminescent material D were suspended, almost no difference was observed in the average phosphorescence lifetime even when the oxygen partial pressure was changed.

[0146] Furthermore, as can be seen from FIG. 16, in the sample aqueous solution 8 in which the lumps of luminous material D were suspended, the behavior of the decay of phosphorescence intensity over time showed almost no difference depending on the oxygen partial pressure.

[0147] According to the present invention, a method for quickly and simply evaluating oxygen partial pressure in the range of 1 mmHg to 160 mmHg using a phosphorescent material can be provided. Also, according to the present invention, a device for quickly and simply evaluating oxygen partial pressure in a wide range including the range of 1 mmHg to 160 mmHg can be provided.

[0148] 11: Measurement unit 12: Control unit 13: Notification unit

Claims

1. A method of evaluating oxygen partial pressure using phosphorescent particles with an average particle size of 9.56 μm or less, based on the difference in the behavior of the phosphorescent particles in terms of the decay of luminescence intensity over time after the irradiation of the excitation light is stopped.

2. The method according to claim 1, wherein the phosphorescent particles used have an average phosphorescent lifetime of 1 ms or more at atmospheric pressure.

3. The phosphorescent particles used are represented by the following formula (1): [where p is the oxygen partial pressure in the ambient environment (unit: mmHg), and τ ０ is the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is 0 (mmHg), and τ ｐ is the phosphorescence lifetime (unit: s) of the phosphorescent particles in an environment where the oxygen partial pressure is p (mmHg). ｄｉｆｆ But when p = 160 (mmHg), it is 0.00003 mmHg －１ s －１ Over 0.30mmHg －１ s －１ 3. The method of claim 1 or 2, wherein:

4. The method according to claim 3, wherein the phosphorescent particles used have crystallinity.

5. A method according to any one of claims 1 to 4, wherein the phosphorescent particles used have a neighboring atom that is the atom closest to an oxygen atom in an oxygen molecule in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby providing a surface on which there is space available for arranging oxygen molecules.

6. A method according to any one of claims 1 to 4, wherein the phosphorescent particles used have a neighboring atom that is the atom closest to an oxygen atom in an oxygen molecule in the surrounding environment, and the distance between the oxygen atom and the neighboring atom is equal to or greater than the sum of the van der Waals radius of the oxygen atom and the van der Waals radius of the neighboring atom, thereby providing three faces on which spaces exist for arranging oxygen molecules.

7. The phosphorescent particles used have a density of 1.10 g / cm ３ 2.00g / cm or more ３ The method according to any one of claims 1 to 6, wherein:

8. The method according to any one of claims 1 to 7, wherein the oxygen partial pressure is evaluated within the range of 1 mmHg to 160 mmHg.

9. The method according to any one of claims 1 to 8, wherein the phosphorescent particles used have a surface coated with a polymer.

10. An apparatus for evaluating oxygen partial pressure, comprising: a measuring unit that uses phosphorescent particles with an average particle size of 9.56 μm or less and measures the luminescence intensity of the phosphorescent particles over time after irradiation with excitation light has stopped; and a control unit that evaluates the oxygen partial pressure based on differences in the behavior of the luminescence intensity attenuated over time measured by the measuring unit.

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