JP7431418B2 - Separation device, stationary phase member, and nanostructure separation method - Google Patents

Description

The technical field of the present specification relates to a separation device for separating nanoparticles, a stationary phase member, and a method for separating nanostructures.

Liquid chromatography is a method for separating target compounds from mixtures. In liquid chromatography, a mobile phase is passed through an adsorbent such as silica gel as a stationary phase. This mobile phase is a liquid containing the compound of interest. The target compound passes through the stationary phase while repeating adsorption and desorption to the stationary phase. Here, the degree of adsorption/desorption and adsorption power of the target compound are different from those of other impurities. Therefore, the target compound can be separated from the mixture.

Various separation devices using liquid chromatography have been developed. For example, Patent Document 1 discloses a technique for gradient elution using two or more types of mobile phase liquids. The value of the internal volume of the mobile phase liquid flow path from the confluence point where multiple mobile phase liquids meet to the sample injection point is memorized, and the time from this value until the composition of the mobile phase liquid starts to change at the sample injection point is calculated. A calculation technique is disclosed (paragraph [0005] of Patent Document 1).

Japanese Patent Application Publication No. 2002-014084

In this way, ordinary liquid chromatography utilizes the interaction between the adsorbent in the stationary phase and the compound in the mobile phase in the ground state or in the non-photoexcited state. In analysis using the same stationary phase, a mobile phase of a constant composition, and at a constant temperature, the compound to be separated is separated at a certain position or eluted at a certain retention time. Therefore, in ordinary liquid chromatography, it is difficult to keep the target substance to be separated in a region other than the determined separation position.

The problem to be solved by the technology of the present specification is to slow down the migration speed of nanostructures, which are separation targets, present in the mobile phase, or to transfer the nanostructures in the mobile phase to the stationary phase. It is an object of the present invention to provide a separation device, a stationary phase member, and a method for separating nanostructures that can separate a target nanostructure by keeping the nanostructure within a certain region.

The separation device in the first aspect includes a stationary phase member having a stationary phase, a development tank capable of accommodating the stationary phase member and the mobile phase, and a light irradiation unit that irradiates light toward the stationary phase member. The stationary phase includes an adsorbent and a plasmonic structure-containing layer in which a plasmonic structure is arranged on the adsorbent. The stationary phase member can be supplied with a mobile phase that includes nanostructures and can move the mobile phase along the stationary phase.

This separation device can excite surface plasmon resonance in the plasmon structure by irradiating it with light. This generates an attractive force between the plasmonic structure and the nanostructure in the mobile phase. Therefore, the separation device can trap and separate the nanostructures by slowing down the movement speed of the nanostructures in the mobile phase liquid or by keeping them within a certain region. Therefore, this separation device can be used as a test device. Moreover, this separation device can be used for manufacturing nanostructures.

In this specification, light irradiation is used to slow down the movement speed of nanostructures, which are separation targets, present in the mobile phase, or to keep the nanostructures in the mobile phase within a certain region in the stationary phase. A separation device, a stationary phase member, and a method for separating nanostructures that can separate target nanostructures are provided.

FIG. 1 is a diagram showing a schematic configuration of a separation device according to a first embodiment. FIG. 3 is a diagram for explaining the structure of the stationary phase member of the first embodiment. FIG. 3 is a diagram conceptually showing the inside of a plasmonic structure-containing layer of the first embodiment. It is a figure showing the flow of the mobile phase in the separation device of a 1st embodiment. It is a figure explaining conventional thin layer chromatography. FIG. 3 is a conceptual diagram for explaining surface plasmon resonance of the first embodiment. FIG. 3 is a diagram showing how gold nanoparticles in a plasmonic structure-containing layer capture inorganic nanoparticles in a mobile phase in the separation device of the first embodiment. 2 is a diffuse reflection spectrum (vertical axis: Kubelker-Munk function) of the stationary phase member (silica gel particle layer supporting gold nanoparticles) of the first embodiment. It is a figure which shows the stationary phase member in the modification of 1st Embodiment. FIG. 7 is a diagram for explaining the structure of a stationary phase member according to a second embodiment. 2 is a TEM image showing rice-shaped ZAIS nanoparticles. It is a photograph of a stationary phase member after ZAIS nanoparticles are developed while irradiating light onto the stationary phase member having a gold nanoparticle-containing layer. It is a photograph of a stationary phase member after ZAIS nanoparticles are developed without irradiating the stationary phase member having a gold nanoparticle-containing layer with light. This is a photograph of a stationary phase member that does not have a gold nanoparticle-containing layer after ZAIS nanoparticles are developed while irradiating the stationary phase member with light. It is a photograph of a stationary phase member after ZAIS nanoparticles are developed without irradiating light onto the stationary phase member that does not have a gold nanoparticle-containing layer. It is a graph showing the relationship between particle diameter and arrival position (Rf value) of quantum dots. It is a photograph showing the case where monochromatic light with a wavelength of 610 nm is applied to ZAIS nanoparticles having a particle diameter of 19 nm on a stationary phase member while changing the light intensity. It is a photograph showing the case where monochromatic light with a wavelength of 610 nm is applied to ZAIS nanoparticles having a particle diameter of 12 nm on a stationary phase member while changing the light intensity. It is a graph showing the relationship between the light intensity of monochromatic light (wavelength 610 nm) irradiated onto a gold nanoparticle-containing layer and the arrival position (Rf value) of ZAIS nanoparticles. It is a micrograph showing a mixed state of oval spherical ZAIS nanoparticles and dumbbell-shaped ZAIS nanoparticles. 1 is a graph showing the particle size distribution of ellipsoidal ZAIS nanoparticles and dumbbell-shaped ZAIS nanoparticles. (a) Photograph of the stationary phase member after developing ZAIS nanoparticles with multiple particle shapes while irradiating monochromatic light (wavelength 610 nm) onto the stationary phase member having a gold nanoparticle-containing layer, (b) Gold nanoparticles (c) A graph of the particle size distribution of ZAIS nanoparticles that were not captured in the containing layer, and (c) a graph of the particle size distribution of ZAIS nanoparticles that were captured in the gold nanoparticle containing layer by light irradiation. The relationship between the diffuse reflection spectrum of gold nanoparticles (vertical axis: Kubelker-Munk function) and the wavelength distribution of red LED light (610 nm) and near-infrared light (820 nm) of Xe lamp light made monochromatic with a bandpass filter. This is a graph showing. It is a graph showing the spectrum of near-infrared light (wavelength 820 nm) of red LED light (wavelength 610 nm) and Xe lamp light monochromatic with a bandpass filter. It is a graph showing the relationship between the irradiation light intensity and the Rf value when ZAIS nanoparticles having a particle diameter of 19 nm are developed while irradiating a gold nanoparticle-containing layer with monochromatic light having a wavelength of 820 nm. The relationship between the diffuse reflection spectra (vertical axis: Kubelker-Munk function) of plasmonic structure-containing layers supporting gold nanoparticles at different densities and the particle number density (numbers in the figure) of the supported gold nanoparticles is shown. It is a graph. It is a graph showing the relationship between the Rf value and the irradiation light intensity and the dependence on the particle number density of gold nanoparticles when rice-shaped ZAIS nanoparticles (19 nm) are developed by irradiating LED light with a wavelength of 610 nm. The particle number density of gold nanoparticles in the gold nanoparticle-containing layer, which is a plasmonic structure-containing layer, and the minimum irradiation light intensity (wavelength) that can trap rice-shaped ZAIS nanoparticles (particle diameter 19 nm) in the gold nanoparticle-containing layer. 610 nm). This is an electron micrograph of gold nanoparticles used as a plasmonic structure. 1 is a table summarizing the number of gold atoms and particle density contained in a plasmonic structure-containing layer when gold nanoparticles of different sizes and shapes are supported. Rf value and irradiation light intensity when rice-shaped ZAIS nanoparticles (19 nm) are developed by irradiating LED light with a wavelength of 610 nm using the plasmonic structure-containing layer supporting gold nanoparticles of various shapes shown in Figure 30. It is a graph showing the relationship between 2 is a graph showing a diffuse reflection spectrum (vertical axis: Kubelker-Munk function) of a plasmonic structure-containing layer supporting silver nanoparticles. This is a photograph of a stationary phase supporting plate after rice-shaped ZAIS nanoparticles (19 nm) were developed while irradiating the plasmonic structure-containing layer supporting silver nanoparticles with blue LED light having a wavelength of 460 nm at various light intensities. 34 is a graph showing the relationship between the monochromatic light intensity at a wavelength of 460 nm and the Rf value of rice-shaped ZAIS nanoparticles (19 nm) in FIG. 33. Graph showing the relationship between the monochromatic light intensity irradiated to the silver nanoparticle-containing layer, which is the plasmonic structure-containing layer, and the minimum irradiation light intensity necessary for capturing rice-shaped ZAIS nanoparticles (19 nm) in the silver nanoparticle-containing layer. It is. It is a graph showing the relationship between the particle size of quantum dots and the Rf value when quantum dots with various particle sizes are developed while irradiating monochromatic light with a wavelength of 460 nm using silver nanoparticles as a plasmon structure. 1 is a graph showing a diffuse reflection spectrum (vertical axis: Kubelker-Munk) of a stationary phase supporting plate supporting ITO particles. It is a photograph of a stationary phase supporting plate when rice-shaped ZAIS nanoparticles (19 nm) are developed while irradiating monochromatic light with a wavelength of 820 nm onto a plasmonic structure-containing layer supporting ITO particles. It is a graph showing the relationship between the irradiation light intensity and the Rf value when rice-shaped ZAIS nanoparticles (19 nm) are developed while irradiating monochromatic light with a wavelength of 820 nm to a plasmonic structure-containing layer supporting ITO particles. This is a photograph of a stationary phase support plate after polystyrene beads were developed as a nanostructure while irradiating a gold nanoparticle-containing layer with monochromatic light having a wavelength of 610 nm. 41 is a graph showing the relationship between the moving distance (cm) of the polystyrene beads from the origin in FIG. 40 and the irradiation light intensity.

Hereinafter, specific embodiments will be described with reference to the drawings, taking as examples a separation device, a stationary phase member, and a method for separating nanostructures. In this specification, a plasmon structure is a material that can excite surface plasmon resonance. Plasmon structures are metal nanoparticles with surface plasmon resonance peaks such as gold (Au) nanoparticles and silver (Ag) nanoparticles, or metal compounds with surface plasmon resonance peaks such as indium tin oxide (ITO) and copper sulfide. They are nanoparticles. As used herein, nanostructures are nanoparticles or molecules made of inorganic or organic compounds. Further, the particle size in this specification is measured by observation using an electron microscope such as a scanning electron microscope or a transmission electron microscope. The size of a particle is the length of the longest line segment that virtually crosses the three-dimensional shape of the particle. However, the size of the octahedral particle is determined by the length of one side of the octahedron.

(First embodiment)
1. Separation Apparatus FIG. 1 is a diagram showing a schematic configuration of a separation apparatus 1000 according to the first embodiment. As shown in FIG. 1, a separation device 1000 uses a stationary phase member 100 to separate nanoparticles. As shown in FIG. 1, the separation apparatus 1000 includes a light irradiation section 1100 and a development tank 1200.

The light irradiation unit 1100 is for irradiating light toward the stationary phase member 100 disposed inside the development tank 1200. The light emitted by the light irradiation unit 1100 irradiates the fixed material (plasmon structure) in the stationary phase member 100 with light that can excite surface plasmon resonance. The energy required to excite surface plasmon resonance varies depending on the material and the surface plasmon resonance peak wavelength. The light emitted by the light irradiation unit 1100 only needs to be able to optically excite the surface plasmon resonance of the plasmon structure, and may be monochromatic light. The light irradiation unit 1100 is, for example, an LED light source or a Xe lamp light source that is converted into monochromatic light through a bandpass filter. Of course, other light sources may be used.

The development tank 1200 can accommodate the stationary phase member 100 and the liquid L1 that is a mobile phase. The development tank 1200 is preferably made of a transparent material. This is to transmit the light from the light irradiation section 1100 and irradiate the stationary phase member 100 with the light. The material of the development tank 1200 is, for example, glass. Of course, other transparent materials may also be used. Liquid L1 is a solvent that is a mobile phase. The liquid L1 may contain inorganic nanoparticles as nanostructures that are separation targets.

2. Stationary phase member (stationary phase support plate)
FIG. 2 is a diagram for explaining the structure of the stationary phase member 100 of the first embodiment. The stationary phase member 100 is a member having a stationary phase of a liquid chromatograph. As shown in FIG. 2, the stationary phase member 100 includes a base material 110, a carrier layer 120, a plasmonic structure-containing layer 130, and a carrier layer 140. The stationary phase member 100 has almost the same structure as a thin layer plate for thin layer chromatography, except for the plasmonic structure-containing layer 130. Therefore, both the carrier layers 120 and 140 and the plasmonic structure-containing layer 130 function as a stationary phase in the chromatography on the base material 110. The stationary phase of the stationary phase member 100 can be supplied with a liquid containing inorganic nanoparticles, which is a separation target to be described later, and allows a mobile phase to move along the stationary phase.

The base material 110 is for supporting the carrier layers 120 and 140 and the plasmonic structure-containing layer 130. The base material 110 does not absorb the liquid L1 and does not allow the liquid L1 to penetrate. The base material 110 is, for example, a glass plate.

The carrier layer 120 is a layer that can permeate liquid L1, which is a mobile phase. The carrier layer 120 is a first carrier layer that does not contain a plasmonic structure but contains an adsorbent. Examples of the material for the adsorbent include silica gel, alumina, activated carbon, diatomaceous earth, filter paper, cellulose, zeolite, and organic polymers. Alternatively, other highly absorbent materials may be used. Carrier layer 120 is solid.

The plasmonic structure-containing layer 130 is a layer for capturing target inorganic nanoparticles present in the mixture. The plasmonic structure-containing layer 130 is disposed between the carrier layer 120 and the carrier layer 140 at a position sandwiched therebetween. The plasmonic structure-containing layer 130 is solid. The plasmonic structure-containing layer 130 can permeate the liquid L1, which is a mobile phase. The plasmonic structure-containing layer 130 contains an adsorbent and a plasmonic structure (metal nanoparticles).

In the plasmonic structure-containing layer 130, metal nanoparticles are sufficiently discretely fixed and arranged on adsorbent particles such as silica gel. The metal nanoparticles may be separated one by one, or may form a certain amount of aggregates. The metal nanoparticles used here may be any material that exhibits a surface plasmon resonance peak, such as gold nanoparticles, silver nanoparticles, copper nanoparticles, or alloy nanoparticles containing them.

The metal nanoparticle is a plasmon structure whose surface plasmon resonance peak can be excited by being irradiated with light from the light irradiation unit 1100. The plasmonic structure-containing layer 130 contains a plasmonic structure.

The carrier layer 140 is a layer that can permeate liquid L1, which is a mobile phase. The carrier layer 140 is a second carrier layer that does not contain a plasmonic structure but contains an adsorbent. Examples of the material for the adsorbent include silica gel, alumina, activated carbon, diatomaceous earth, filter paper, cellulose, zeolite, and organic polymers. Alternatively, other highly absorbent materials may be used. Carrier layer 140 is solid.

The carrier layer 120, the plasmonic structure-containing layer 130, and the carrier layer 140 are stationary phases into which the liquid L1, which is a mobile phase, can be moved. That is, the liquid L1, which is the mobile phase, can move inside the carrier layer 120, the plasmonic structure-containing layer 130, and the carrier layer 140 along the stationary phase.

FIG. 3 is a diagram conceptually showing the inside of the plasmonic structure-containing layer 130. Examples of the plasmonic structure include metal nanoparticles P1 having a particle size of 1 nm or more and 500 nm or less. The metal nanoparticles P1 may be arranged discretely on the adsorbent while being aggregated in numbers of several to several hundred. Alternatively, the metal nanoparticles P1 may be completely discrete, uniformly dispersed and fixed one by one on the adsorbent. In the adsorbent, metal nanoparticles P1 are sparsely arranged at a size of several hundred μm or less.

3. Liquid (mobile phase)
Liquid L1 is a mobile phase that moves relative to the stationary phase. The nanostructures to be separated move in the stationary phase together with the mobile phase while repeating adsorption and desorption to the stationary phase between the mobile phase and the stationary phase. Nanostructures are, for example, inorganic nanoparticles. Therefore, the liquid L1 used only needs to have even a slight ability to uniformly disperse or dissolve the inorganic nanoparticles to be separated. The mixture containing the target inorganic nanoparticles does not need to be dispersed in the liquid L1 from the beginning.

FIG. 4 is a diagram showing the flow of the mobile phase in the separation apparatus 1000 of the first embodiment. As shown in FIG. 4, liquid L1 penetrates into the stationary phase in the direction of arrow J1. The liquid L1, which is a mobile phase, moves inside the carrier layer 120, the plasmonic structure-containing layer 130, and the carrier layer 140, which are stationary phases, but cannot move inside the base material 110. This is similar to thin layer chromatography.

4. Inorganic nanoparticles (nanostructures)
Inorganic nanoparticles are nanostructures that are targeted by plasmonic structures to trap or slow down their migration speed. The size of the inorganic nanoparticles is, for example, 0.5 nm or more and 100 nm or less. The inorganic nanoparticles are preferably supported in advance in the form of dots on a small portion of the carrier layer 120, similarly to thin layer chromatography. In this case, the inorganic nanoparticles are supplied to the mobile phase when the mobile phase (liquid L1) penetrates into the stationary phase in the direction of arrow J1. Alternatively, the liquid L1 in which inorganic nanoparticles are dispersed may be supplied to the carrier layer 120 of the stationary phase member 100. Here, examples of inorganic nanoparticles include nanoparticles of metals, alloys, semiconductors, metal oxides, and the like.

Examples of elements forming inorganic nanoparticles include Mg, Zn, Cd, Hg, Al, Ga, In, Ti, Zr, Si, Ge, Sn, Pb, Fe, Ru, Co, Rh, Ir, Ni, and Pd. , Pt, V, Ta, Nb, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Sb, Bi, S, Se, Te, F, Cl, Br, and I. Further, elements other than those mentioned above may be used.

5. Thin layer chromatography (TLC)
FIG. 5 is a diagram illustrating conventional thin layer chromatography. The separation apparatus 1000 of this embodiment is different from thin layer chromatography. However, the separation apparatus 1000 has some parts in common with thin layer chromatography. Therefore, thin layer chromatography will be briefly explained.

The TLC plate C1 is, for example, one in which silica gel particles are supported as a stationary phase on the surface of glass to a thickness of several hundred μm. Sample S1 is dropped in dots at the origin (K1) of TLC plate C1, dried and supported. Then, when the lower part (K1 side) of the TLC plate C1 is immersed in the developing solvent, the developing solvent moves in a direction parallel to the arrow J2 due to capillary action. Here, the silica gel of TLC plate C1 is the stationary phase, and the developing solvent is the mobile phase.

Sample S1 moves in the direction of arrow J2. However, the sample S1 actually rises in the direction of the arrow J2 while repeating adsorption and desorption to the silica gel carrier. Therefore, for example, when the developing solvent reaches from position K1 to position K3, sample S1 reaches from position K1 to position K2. In this way, a difference occurs between the position reached by the developing solvent and the position reached by the sample S1. There is a difference between the distance traveled by the mobile phase itself and the distance traveled by the target compound in the mobile phase.

Here, the Rf value can be defined as follows.
Rf = W2/W1
The distance W1 is the moving distance of the developing solvent. The distance W2 is the moving distance of the sample S1. If the composition of the developing solvent, temperature, carrier, and spot amount are controlled, the Rf value is reproducible. Therefore, thin layer chromatography can be used to separate and identify sample S1.

When thin layer chromatography is used in this manner, a target compound can also be separated from a mixture sample using a developing solvent. However, when attempting to separate and identify nanoparticles using this method as sample S1, the arrival position K2 where the target nanoparticles stop is not necessarily sufficiently separated from the arrival position of contaminants. . Furthermore, the nanoparticles to be separated are not necessarily colored.

6. Principle of Separating Particles In the first embodiment, an inorganic nanoparticle mixture containing a target object is expanded with a liquid L1, and surface plasmon resonance of the metal nanoparticles in the plasmon structure-containing layer 130 is optically excited. This makes use of the force that acts selectively on inorganic nanoparticles to selectively capture target inorganic nanoparticles. Alternatively, the movement speed of the target inorganic nanoparticles is selectively slowed down. This separates the target nanoparticles from impurities present in the mixture used as a sample.

6-1. Surface Plasmon Resonance FIG. 6 is a conceptual diagram for explaining local surface plasmon resonance of the first embodiment. The horizontal axis in FIG. 6 represents the traveling direction of light waves. The vertical axis in FIG. 6 represents the electric field strength of light. FIG. 6 depicts metal nanoparticles exhibiting surface plasmon resonance, such as gold nanoparticles P1a, P1b, and P1c. Gold nanoparticles P1a, P1b, and P1c may be considered as three particles located at different positions. Furthermore, the gold nanoparticles P1a, P1b, and P1c may be considered to represent the state of one gold nanoparticle P1 at different times.

Light propagates while forming oscillating electric and magnetic fields. Objects that are large enough for humans to recognize with the naked eye are sufficiently large compared to the wavelength of light. Therefore, the influence of the electric field of light rarely appears as a phenomenon. However, nanoparticles with a size on the order of the wavelength of light or less are affected by the local electric field formed by light.

The gold nanoparticles P1a are subjected to an upward electric field formed by light. Therefore, the electrons of the gold nanoparticles P1a gather at the lower side in the figure. The gold nanoparticles P1b are subjected to a downward electric field formed by light. Therefore, the electrons of the gold nanoparticles P1b gather at the upper side in the figure. The gold nanoparticles P1c are subjected to an upward electric field formed by light. Therefore, the electrons of the gold nanoparticles P1c gather at the lower side in the figure.

Therefore, the electrons of the gold nanoparticles P1 oscillate in response to the electric field of the light. In other words, a collective oscillation phenomenon of electrons occurs. In this way, surface plasmon resonance is optically excited. As will be described later, this surface plasmon resonance forms a strong local electric field near the metal nanoparticle, and this local electric field plays an important role in trapping the nanoparticle.

6-2. Force acting on inorganic nanoparticles in mobile phase A local electric field corresponding to the electric field intensity of light is generated around the plasmon-excited gold nanoparticles P1 as described above. Gold nanoparticles P1 are immobilized on a stationary phase. The nanoparticles in the mobile phase move in the electric field of the light and the electric field formed by the gold nanoparticles P1 in the stationary phase. However, the electric field of light felt by the target inorganic nanoparticles is very weak, and the electric field felt by the nanoparticles in the mobile phase may be approximated by a localized electric field formed by the gold nanoparticles P1, which has a higher intensity.

Therefore, the nanoparticles in the mobile phase are subjected to an attractive force F expressed by the following equation.
F = (1/2)・α・∇E ²
F: Attractive force acting on nanoparticles in the mobile phase
α: Polarizability of nanoparticles in mobile phase
E: Local electric field formed by gold nanoparticles

FIG. 7 is a diagram showing how gold nanoparticles P1 of the plasmonic structure-containing layer 130 capture inorganic nanoparticles N1 in the mobile phase in the separation device 1000 of the first embodiment. In this way, while the light irradiation section 1100 continues to irradiate light toward the stationary phase member 100, the photoexcited gold nanoparticles P1 continue to form a local electric field E. The inorganic nanoparticles N1 in the mobile phase are decelerated by the attractive force caused by the local electric field E. When the local electric field E is strong, the inorganic nanoparticles N1 in the mobile phase are captured by the gold nanoparticles P1. In other words, while the light irradiation unit 1100 continues to irradiate light toward the stationary phase member 100, the gold nanoparticles P1 in the stationary phase selectively slow down the movement speed of the inorganic nanoparticles N1 in the mobile phase. or continue to completely capture the inorganic nanoparticles N1.

Note that the inorganic nanoparticles N1 have different sizes. The inorganic nanoparticles N1 having different sizes have different polarizabilities. In other words, different forces act on the inorganic nanoparticles N1 having different particle sizes.

In this manner, the plasmonic structures (metal nanoparticles) of the plasmonic structure-containing layer 130 exert an attractive force on the inorganic nanoparticles N1 in the mobile phase by exciting surface plasmons. Therefore, the plasmonic structure-containing layer 130 captures the inorganic nanoparticles N1 in the mobile phase or reduces the moving speed of the inorganic nanoparticles N1 in the mobile phase during the period of light irradiation.

6-3. Wavelength of Light Irradiation Unit The larger the output of the light irradiated by the light irradiation unit 1100 of the separation device 1000, the larger the electric field that is formed tends to be. Furthermore, there is a suitable wavelength range of light for plasmon excitation of the plasmon structure (gold nanoparticles P1).

FIG. 8 is a diffuse reflection spectrum of the stationary phase member 100 of the first embodiment in which gold nanoparticles P1 are used as the plasmonic structure and silica gel particles are used as the stationary phase. The horizontal axis in FIG. 8 is the wavelength of light. The vertical axis in FIG. 8 is the Kubelker-Munk function. Here, the plasmonic structure-containing layer 130 of the stationary phase member 100 includes gold nanoparticles (particle diameter: 12 nm). As shown in FIG. 8, a broad surface plasmon resonance peak is observed in the wavelength region of 500 nm or more for the stationary phase member 100 having the plasmon structure-containing layer 130. In particular, the Kubelker-Munk function is large in the wavelength range from 600 nm to 900 nm. In other words, this indicates that the light absorption and scattering of the stationary phase member 100 are large in this wavelength range.

Therefore, for the gold nanoparticles, the light emitted by the light irradiation unit 1100 is preferably light in this wavelength range. When the light irradiation unit 1100 irradiates light in this wavelength range toward the stationary phase member 100, the energy of the irradiated light is used for surface plasmon excitation of the plasmon structure-containing layer 130 of the stationary phase member 100.

In the first embodiment, the light irradiation unit 1100 irradiates the stationary phase member 100 with red light having a wavelength of 610 nm, for example. Therefore, in the plasmon structure-containing layer 130, the gold nanoparticles P1 cause relatively strong plasmon excitation.

7. Method for separating nanoparticles in mobile phase 7-1. Development tank housing process First, in the lower part of the stationary phase member 100, as in the case of a thin layer plate for thin layer chromatography (position K1 in FIG. 5), a sample solution containing the target inorganic nanoparticles is poured. Drop a small amount, dry and support. At this time, the sample is fixed in a region of the carrier layer 120 outside the plasmonic structure-containing layer 130. This stationary phase member 100 is housed inside a development tank 1200. As a result, the stationary phase having the plasmonic structure-containing layer 130 is housed inside the deployment tank 1200. Further, the liquid L1 is accommodated inside the development tank 1200. At this time, the amount of liquid L1 is adjusted so that the position of the sample supported on stationary phase member 100 is higher than the liquid level of liquid L1.

7-2. Light Irradiation Step As soon as the stationary phase member 100 and the liquid L1 (mobile phase) are placed inside the development tank 1200, the mobile phase begins to rise along the stationary phase due to capillary action. Immediately thereafter, the stationary phase member 100 in the development tank 1200 is irradiated with light from the light irradiation unit 1100. The light irradiation unit 1100 may particularly irradiate the plasmon structure-containing layer 130 with light.

By irradiating light toward the stationary phase member 100 in this manner, surface plasmons are excited in the gold nanoparticles P1 in the plasmon structure-containing layer 130. The mobile phase of the liquid L1 moves from the carrier layer 120 of the stationary phase member 100 toward the plasmonic structure-containing layer 130. In the plasmon structure-containing layer 130, gold nanoparticles P1 are discretely arranged, and a localized electric field is generated by exciting the surface plasmon resonance of the gold nanoparticles P1. The target inorganic nanoparticles N1 move up the stationary phase member 100 while repeating adsorption and desorption with the stationary phase together with the liquid L1 that is the mobile phase. At this time, when the mobile phase passes through the gold nanoparticle P1, a localized electric field due to the surface plasmon generated near the gold nanoparticle P1 causes the gold nanoparticle P1, which is a plasmon structure, to interact with the inorganic nanoparticles in the mobile phase. Attractive force acts between the particles N1 and the moving speed of the inorganic nanoparticles N1 in the mobile phase is reduced. Alternatively, the inorganic nanoparticles N1 in the mobile phase are completely captured near the gold nanoparticles P1.

Then, the mobile phase of the liquid L1 reaches the carrier layer 140 above the plasmonic structure-containing layer 130. On the other hand, during the period when the light irradiation section 1100 is irradiating the stationary phase member 100 with light, an attractive force is generated between the gold nanoparticles P1 of the plasmonic structure-containing layer 130 and the inorganic nanoparticles N1 in the mobile phase. continues to work. Therefore, the moving speed of the inorganic nanoparticles N1 is reduced in the plasmonic structure-containing layer 130, or the inorganic nanoparticles N1 are completely captured near the gold nanoparticles P1, which are plasmonic structures, and are contained in the sample. Separated from any contaminants present.

Thus, inside the carrier layers 120, 140, the mobile phase and the inorganic nanoparticles N1 move at a normal moving speed. As mentioned above, the movement speed of the inorganic nanoparticles N1 is slower than the movement speed of the mobile phase. On the other hand, inside the plasmon structure-containing layer 130 during light irradiation, the mobile phase moves at a normal moving speed, and the inorganic nanoparticles N1 are further slowed down or captured.

7-3. Other Steps After that, the stationary phase member 100 is dried so that the target nanoparticles do not move, and the mobile phase is removed. Then, the plasmonic structure-containing layer 130 can be peeled off from the base material 110, and the target inorganic nanoparticles N1 can be extracted with a solvent. When the plasmonic structure-containing layer 130 is peeled off, there is no need for light irradiation since there is no mobile phase. The target inorganic nanoparticles N1 are thus separated. For example, the inorganic nanoparticles N1 thus collected may be sent for inspection.

In this way, the technique of the first embodiment can be said to be a type of liquid chromatograph that uses a liquid as a mobile phase and a solid as a stationary phase. Further, in the first embodiment, a stationary phase containing a plasmon structure capable of optically exciting surface plasmon resonance is used, and a liquid containing a nanostructure is used as a mobile phase. By irradiating the plasmonic structure-containing layer 130 with light, surface plasmon resonance is excited in the plasmonic structure, and the plasmonic structure (gold nanoparticles P1) in the stationary phase and the nanostructure (inorganic nanoparticles) in the mobile phase are N1). As a result, the nanostructures are captured by the plasmonic structure, or the movement speed of the nanostructures in the mobile phase is slowed down.

8. Effects of the first embodiment The separation device 1000 can separate the target inorganic nanoparticles N1 from the mixture. At that time, high-power lasers like optical tweezers technology are not required. Furthermore, during the period in which the plasmon structure-containing layer 130 is irradiated with light, the plasmon structure-containing layer 130 slows down the movement speed of the inorganic nanoparticles N1 in the mobile phase in the liquid L1, or the inorganic nanoparticles N1 maintain a state of capture.

Therefore, this separation device 1000 can be used as an inspection device for separating nanoparticles. Further, the separation apparatus 1000 can also be used as a manufacturing apparatus for separating and mass-producing nanoparticles.

9. Modification 9-1. Plural Layers Containing Plasmonic Structures FIG. 9 is a diagram showing a stationary phase member 200 in a modification of the first embodiment. The stationary phase member 200 includes a base material 110 , a support layer 120 , a first plasmonic structure-containing layer 230 , a support layer 140 , a second plasmonic structure-containing layer 250 , and a support layer 160 . The first plasmon structure-containing layer 230 and the second plasmon structure-containing layer 250 have plasmon structures that exhibit different plasmon wavelengths. For example, one contains gold nanoparticles and the other contains silver nanoparticles. Therefore, the first plasmonic structure-containing layer 230 can capture the first inorganic nanoparticles in the mixture, and the second plasmonic structure-containing layer 250 can capture the second inorganic nanoparticles in the mixture. In this way, the stationary phase member may include a plurality of plasmonic structure-containing layers.

9-2. Manufacturing process The inorganic nanoparticles N1 after separation can be used for inspection. However, the separated inorganic nanoparticles N1 may be passed on to subsequent processing steps. In this way, a material using the inorganic nanoparticles N1 as a raw material is manufactured.

9-3. Wavelength of Light The wavelength of the light emitted by the light irradiation unit 1100 is sufficient as long as it can optically excite the surface plasmon resonance of the plasmon structure of the plasmon structure-containing layer 130, and is approximately a visible light wavelength or a near-infrared wavelength. The wavelength of the light is, for example, about 400 nm or more and 1000 nm or less. However, wavelengths shorter or longer than this wavelength range may also be used.

9-4. Timing of Light Irradiation The light irradiation unit 1100 may irradiate light toward the development tank 1200 before the stationary phase member 100 is placed inside the development tank 1200.

9-5. Immersion in Solvent The stationary phase member 100 may be immersed in a solvent in advance. This is because the mobile phase containing the inorganic nanoparticles N1 may easily rise to an upper position of the stationary phase member 100. Examples of the solvent include chloroform, toluene, and oleylamine. Of course, solvents other than those mentioned above may also be used.

9-6. Base Material The stationary phase member 100 has a base material 110. As long as the carrier layer 120, the plasmonic structure-containing layer 130, and the carrier layer 140 can stand on their own, and the characteristics of the stationary phase of the stationary phase member 100 are satisfied, the base material 110 may be omitted.

9-7. Combination The above modifications may be freely combined.

(Second embodiment)
A second embodiment will be described. The stationary phase member of the second embodiment is different from the stationary phase member of the first embodiment. Therefore, the stationary phase member will be explained.

1. Stationary Phase Member FIG. 10 is a diagram for explaining the structure of a stationary phase member 300 of the second embodiment. The stationary phase member 300 includes a base material 110, a carrier layer 120, a plasmonic structure-containing layer 330, and a carrier layer 140. The stationary phase member 300 includes an adsorbent and a plasmonic structure-containing layer 330 in which a plasmonic structure is arranged on the adsorbent. The stationary phase member 300 can be supplied with a mobile phase containing nanostructures and can move the mobile phase along the stationary phase.

Metal compound nanoparticles capable of exciting surface plasmon resonance can be used as the plasmon structure fixed to the stationary phase. This metal compound nanoparticle has a size capable of exciting surface plasmon resonance and a surface plasmon resonance peak. Examples of the size that can excite surface plasmon resonance include particles with a particle size of 1 nm or more and 500 nm or less.

Examples of the material of the plasmonic structure include metal compounds such as metal oxides, conductive metal composite oxides, and the like. Examples of metal oxides include molybdenum oxide, rhenium oxide, and tungsten oxide. Examples of other metal compounds include copper sulfide and silver sulfide. Examples of the conductive metal composite oxide include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), and the like.

2. Effects of the Second Embodiment The plasmon structure-containing layer of the stationary phase member 300 excites surface plasmon resonance during the period in which the light irradiation unit 1100 irradiates the stationary phase member with light. Thereby, the plasmonic structure captures the inorganic nanoparticles N1 or reduces the moving speed of the inorganic nanoparticles N1 in the mobile phase.

(Third embodiment)
A third embodiment will be described. The nanostructures of the third embodiment are different from the nanostructures of the first embodiment. Therefore, the nanostructures to be separated will be explained.

1. Nanostructures The mobile phase liquid L1 may or may not contain nanostructures. A nanostructure refers to a structure with a size of 0.5 nm or more and 100 nm or less.

Examples of nanostructures include organic compounds. Examples of organic compounds include organic polymers such as polyethylene and polystyrene, large organic molecules such as dendrimers and π-conjugated molecules, and biomolecules such as DNA, proteins, peptides, antigens, antibodies, exosomes, viruses, and cells. and biologically related substances. Further, the organic compound may be a nano-sized aggregate of organic molecules such as a micelle or a vesicle. These are just examples, and other compounds may be used.

3. Effects of the Third Embodiment The plasmon structure-containing layer of the stationary phase excites surface plasmon resonance during the period in which the light irradiation unit 1100 irradiates the stationary phase member with light. Thereby, the plasmonic structure traps the nanostructure or slows down the movement speed of the nanostructure in the mobile phase.

(Combination of embodiments)
The first embodiment and its modifications, the second embodiment, and the third embodiment may be freely combined.

(experiment)
A. Gold nanoparticles (plasmon structure)
1. Experimental method 1-1. Stationary phase member (stationary phase support plate)
Two types of stationary phase supporting plates were prepared. The first type of stationary phase supporting plate is a normal TLC plate on which a plasmon structure-containing layer is formed. Here, the plasmonic structure is a gold nanoparticle. This first type of stationary phase supporting plate corresponds to the stationary phase member 100 of the first embodiment. The second type of stationary phase supporting plate is a normal TLC plate.

An octadecyl group-modified reversed-phase silica gel TLC plate (Uniplate P50031, manufactured by Analtech), in which silica gel particles were applied and fixed on a glass plate and the surface was chemically treated, was used. Hydrophilic gold nanoparticles (particle diameter: 12 nm) whose surface has been modified with citric acid are coated on a band-shaped region perpendicular to the flow direction of the mobile phase (arrow J1) and dried to form a region containing a plasmonic structure. formed a layer. The particles do not disperse in organic solvents such as chloroform. Note that the region where the gold nanoparticles are immobilized is the region where the Rf value is from 0.20 to 0.375 after the development with the mobile phase is finally completed.

1-2. Rice-shaped ZAIS nanoparticles (quantum dots)
Rice-shaped ZAIS nanoparticles were produced using the method described in the literature (ACS Appl. Mater. Interfaces 8 (2016) 27151-27161). Here, ZAIS refers to a solid solution semiconductor between ZnS and AgInS ₂ , and its composition is represented by (AgIn) _x Zn _{2 (1-x)} S ₂ .

Silver acetate, indium acetate, and zinc acetate were used as metal sources, with the respective ratios being Ag(OAc):In(OAc) ₃ :Zn(OAc) ₂ =x:x:2(1-x). did. Rice-shaped ZAIS nanoparticles were obtained by thermally decomposing these mixtures together with a sulfur compound in oleylamine at 150°C to 250°C.

By setting the charging ratio x to 0.50 and 0.90, ZAIS nanoparticles with average particle diameters of 19 nm and 12 nm were obtained, respectively. Here, the particle diameter is the longest length of the particle. In order to measure the particle size, observation was performed using a transmission electron microscope (TEM).

FIG. 11 is a TEM image showing rice-shaped ZAIS nanoparticles (average particle diameter 19 nm) obtained by the above method.

Note that the particle size of ZAIS nanoparticles can be changed by changing the manufacturing conditions.

1-3. Light irradiation section A red LED light source was used as the light irradiation section. The red LED light source can emit monochromatic light with a peak wavelength of 610 nm.

1-4. Procedure A chloroform solution containing ZAIS nanoparticles was dropped at the center of the area of the carrier layer 120 of the stationary phase member (stationary phase support plate). Then, the sample solution was dried, and ZAIS nanoparticles were dotted onto the stationary phase of the stationary phase support plate as inorganic nanoparticles serving as targets for light capture.

A stationary phase support plate supporting ZAIS nanoparticles was placed in a development tank. Next, a developing solvent (a mixed solution of oleylamine and chloroform) was placed in the developing tank, and the stationary phase supporting plate was irradiated with monochromatic light having a wavelength of 610 nm. Then, I observed what happened after that.

2. Experimental results 2-1. Presence or absence of plasmonic structure-containing layer FIG. 12 is a photograph of the stationary phase member after the mobile phase was supplied while irradiating monochromatic light with a wavelength of 610 nm to the stationary phase member having the gold nanoparticle-containing layer. As shown by the arrow at the bottom center of FIG. 12, inorganic nanoparticles (quantum dots: QDs) are trapped within the region of the gold nanoparticle-containing layer.

FIG. 13 is a photograph of the stationary phase member after the mobile phase was supplied without irradiating light to the stationary phase member having the gold nanoparticle-containing layer. As shown by the arrow near the top of FIG. 13, the ZAIS nanoparticles (quantum dots) are present above the region of the gold nanoparticle-containing layer.

FIG. 14 is a photograph of a stationary phase member that does not have a gold nanoparticle-containing layer after a mobile phase is supplied while irradiating monochromatic light with a wavelength of 610 nm to the stationary phase member. Light irradiation was performed at the same position as the stationary phase member having the gold nanoparticle-containing layer shown in FIG. As shown in FIG. 14, ZAIS nanoparticles (quantum dots) are present near the arrow at the top of the stationary phase member. This position was almost the same as the position of the ZAIS nanoparticles in FIG.

FIG. 15 is a photograph of a stationary phase member that does not have a gold nanoparticle-containing layer after a mobile phase is supplied to the stationary phase member without irradiating it with light. As shown in FIG. 15, ZAIS nanoparticles (quantum dots) are present near the arrow at the top of the stationary phase member. This position was approximately the same as the position of the ZAIS nanoparticles in FIGS. 13 and 14.

Table 1 is a table summarizing the above results. As shown in Table 1, only when the stationary phase member 100 of the first embodiment is irradiated with light, the stationary phase member 100 has ZAIS nanoparticles (quantum dots) in the gold nanoparticle-containing layer (plasmon structure-containing layer). can be captured.

[Table 1]
Sample Gold nanoparticle-containing layer Light capture Sample 1 Yes Yes ○
Sample 2 Yes No ×
Sample 3 No Yes ×
Sample 4 None None ×

2-2. Particle size dependence of quantum dots as separation targets Rice-shaped ZAIS nanoparticles with particle sizes of 7.7 nm, 12 nm, and 19 nm were prepared based on the method in the literature (ACS Appl. Mater. Interfaces 8 (2016) 27151-27161). was prepared by changing the reaction conditions. Spherical AgInGaS nanoparticles with particle diameters of 3.0 nm, 4.5 nm, and 6.0 nm were produced by improving the method described in the literature (ACS Appl. Mater. Interfaces 10 (2018) 42844-42855). These particles were used as quantum dots.

FIG. 16 is a graph showing the relationship between particle diameter and arrival position of quantum dots. The horizontal axis in FIG. 16 is the particle diameter of the quantum dot. The vertical axis in FIG. 16 is the Rf value at the position of the quantum dot in the stationary phase member. Note that the region of the gold nanoparticle-containing layer is a region where the Rf value is from 0.20 to 0.375 after the mobile phase is developed. The gold nanoparticle-containing layer region was irradiated with LED light having a wavelength of 610 nm and an output of 0.89 W/cm ² to develop quantum dots using a mobile phase.

As shown in FIG. 16, even if light irradiation is performed, inorganic nanoparticles having a particle size of about 8 nm or less pass through the region of the gold nanoparticle-containing layer. On the other hand, by performing light irradiation, inorganic nanoparticles having a particle size larger than about 8 nm are captured in the gold nanoparticle-containing layer. In this way, the separation device 1000 tends to more easily capture inorganic nanoparticles with larger particle diameters.

2-3. Light intensity dependence Figure 17 shows the stationary phase member after the stationary phase member in the gold nanoparticle-containing layer was irradiated with light while changing the irradiation light intensity when rice-shaped ZAIS nanoparticles with a particle diameter of 19 nm were developed using a mobile phase. This is a photo. As shown in Figure 17, when the particle diameter is 19 nm, when the stationary phase member is irradiated with LED light of 610 nm wavelength and an output of 0.63 W/cm ² or more, the gold nanoparticle-containing layer captures the inorganic nanoparticles. We were able to.

FIG. 18 is a photograph of the stationary phase member of the gold nanoparticle-containing layer after the stationary phase member of the gold nanoparticle-containing layer was irradiated with light while changing the light intensity when rice-shaped ZAIS nanoparticles with a particle diameter of 12 nm were developed using a mobile phase. As shown in Figure 18, when the particle diameter is 12 nm, when the stationary phase member is irradiated with LED light of wavelength 610 nm with an output of 0.76 W/cm ² or more, the gold nanoparticle-containing layer captures the inorganic nanoparticles. We were able to.

FIG. 19 is a graph showing the relationship between the intensity of monochromatic light with a wavelength of 610 nm applied to the gold nanoparticle-containing layer and the arrival position of the rice-shaped ZAIS nanoparticles. The horizontal axis in FIG. 19 is the intensity of monochromatic light irradiated onto the gold nanoparticle-containing layer. The vertical axis in FIG. 19 is the Rf value of the position reached by the inorganic nanoparticles in the stationary phase member. FIG. 19 is a graph summarizing the results of FIGS. 17 and 18.

As shown in FIG. 19, the gold nanoparticle-containing layer can suitably capture inorganic nanoparticles by increasing the light intensity, regardless of the particle size. Furthermore, even when the light intensity was not sufficient to capture the inorganic nanoparticles, the Rf value at the position where the nanoparticles arrived was smaller than when no light was irradiated. This indicates that the moving speed of inorganic nanoparticles in the mobile phase can be reduced by irradiating the gold nanoparticle-containing layer with light.

2-4. Separation of Quantum Dot Mixture with Different Particle Sizes FIG. 20 is a transmission electron micrograph of a quantum dot mixture consisting of elliptic spherical ZAIS nanoparticles and dumbbell-shaped ZAIS nanoparticles. Dumbbell-shaped ZAIS nanoparticles were produced using the method described in the literature (J. Phys. Chem. C. 122, 25, (2018) 13705-13715). Oval spherical ZAIS nanoparticles are present in the circles on the left side of FIG. 20. Dumbbell-shaped ZAIS nanoparticles are present in the circles on the right side of FIG.

FIG. 21 is a particle size distribution showing the particle sizes and proportions of elliptic spherical ZAIS nanoparticles and dumbbell-shaped ZAIS nanoparticles contained in the quantum dot mixture. The horizontal axis in FIG. 21 is the particle diameter of ZAIS nanoparticles. The vertical axis in FIG. 21 is the frequency of appearance of ZAIS nanoparticles of the particle size.

FIG. 22(a) is a photograph of the stationary phase member after the quantum dot mixture was developed in a mobile phase while being irradiated with LED light having a wavelength of 610 nm (light intensity: 0.63 W/cm ² ). It can be seen that the quantum dots were separated into the quantum dots captured in the gold nanoparticle-containing layer, which is the plasmon structure-containing layer, and the quantum dots that were expanded above it.

FIG. 22(b) is a graph showing the particle size distribution of ZAIS nanoparticles at a position above the gold nanoparticle-containing layer. FIG. 22(c) is a graph showing the particle size distribution of ZAIS nanoparticles at the position of the gold nanoparticle-containing layer.

As shown in Figure 22(b)(c), the gold nanoparticle-containing layer selectively captures ZAIS nanoparticles with a particle size larger than about 8 nm, and captures smaller ZAIS nanoparticles with a particle size of 8 nm or less. There wasn't. In this way, the separation device can separate nanoparticles having different particle sizes according to their particle sizes.

2-5. Effect of wavelength of irradiation light Figure 23 shows the diffuse reflection spectrum (vertical axis: Kubelker-Munk function) of the gold nanoparticle-containing layer, which is a plasmonic structure-containing layer, and the band of red LED light (wavelength: 610 nm) and Xe lamp light. It is a graph showing the relationship between the wavelength range of near-infrared light (wavelength: 820 nm) that has been made monochromatic by passing through a pass filter. The horizontal axis in FIG. 23 is wavelength. Both the wavelength region of red light with a wavelength of 610 nm and the wavelength region of near-infrared light with a wavelength of 820 nm overlap with the broad surface plasmon resonance peak of the gold nanoparticles. Therefore, surface plasmon resonance can be effectively optically excited.

FIG. 24 is a graph showing the spectrum of near-infrared light (wavelength: 820 nm) that is made monochromatic by passing red LED light (wavelength: 610 nm) and Xe lamp light through a bandpass filter. The horizontal axis in FIG. 24 is the wavelength of light. The vertical axis in FIG. 24 is the intensity of light. Note that the vertical axis is normalized by the maximum peak intensity value of each optical spectrum.

When developing rice-shaped ZAIS nanoparticles with a particle diameter of 19 nm using a mobile phase, the stationary phase member of the gold nanoparticle-containing layer was irradiated with light while changing the wavelength of the irradiation light.

FIG. 25 is a graph showing the relationship between the light intensity and the Rf value when monochromatic light with a wavelength of 820 nm having the spectrum shown in FIG. 24 is irradiated. The horizontal axis in FIG. 25 is the intensity of light. The vertical axis in FIG. 25 is the Rf value. Compared to the case where rice-shaped ZAIS nanoparticles with a particle diameter of 19 nm are expanded while being irradiated with monochromatic light with a wavelength of 610 nm (Fig. 19), the light intensity of the Rf value is lower even when irradiated with light with a wavelength of 820 nm (Fig. 25). No significant difference was observed in dependence.

In the diffuse reflection spectrum (FIG. 23) of the gold nanoparticle-containing layer, which is the plasmonic structure-containing layer, the Kubelker-Munk function values at wavelengths of 610 nm and 820 nm are almost the same. Therefore, when the stationary phase member is irradiated with light at the same light intensity, the excitation efficiency of surface plasmon resonance at wavelengths of 610 nm and 820 nm is almost the same. Therefore, there is almost no difference in Rf value.

2-6. Effect of particle number density of supported gold nanoparticles Plasmon structure-containing layers were fabricated by changing the particle number density of gold nanoparticles.

FIG. 26 is a graph showing the relationship between the diffuse reflection spectrum of the gold nanoparticle-containing layer and the particle number density of gold nanoparticles. The horizontal axis in FIG. 26 is the wavelength of light. The vertical axis in FIG. 26 is the value of the Kubelker-Munk function. As shown in FIG. 26, the higher the particle number density of gold nanoparticles that are plasmonic structures, the larger the value of the Kubelker-Munk function.

Using a stationary phase member having a gold nanoparticle-containing layer as the plasmonic structure-containing layer in FIG. 26, rice-shaped ZAIS nanoparticles with a particle diameter of 19 nm are expanded by a mobile phase, and at that time, the irradiation light intensity is changed to It was irradiated with 610 nm LED light.

FIG. 27 is a graph showing the relationship between light intensity and the Rf value of ZAIS nanoparticles and the dependence on the particle number density of gold nanoparticles. The horizontal axis in FIG. 27 is the intensity of light. The vertical axis in FIG. 27 is the Rf value. The numbers in FIG. 27 are particle number densities of supported gold nanoparticles. As shown in FIG. 27, the higher the particle number density of gold nanoparticles that are plasmonic structures, the more ZAIS nanoparticles can be captured with a weaker irradiation light intensity.

Figure 28 shows the particle number density of gold nanoparticles in the plasmonic structure-containing layer and the minimum irradiation light intensity (Imin) (irradiation It is a graph showing the relationship with light wavelength: 610 nm). The horizontal axis in FIG. 28 is the particle number density of gold nanoparticles. The vertical axis in FIG. 28 is the intensity of the irradiated light. As shown in FIG. 28, the higher the particle number density of gold nanoparticles, the more ZAIS nanoparticles with a particle size of 19 nm can be captured with light of weaker intensity.

2-7. Shape Dependency of Gold Nanoparticles Used as Plasmon Structures FIG. 29 is an electron micrograph of gold nanoparticles used as plasmon structures. As shown in FIG. 29, spherical gold nanoparticles with a particle size of 12 nm, octahedral gold nanoparticles with a particle size of 75 nm, and spherical gold nanoparticles with a particle size of 82 nm are assembled into a plasmonic structure. Using. Note that the octahedral particle size is the length of one side of the octahedron.

The gold nanoparticles shown in FIG. 29 were used in the plasmonic structure-containing layer.

FIG. 30 is a table summarizing the number of gold atoms in the gold nanoparticle-containing layer and the particle density of gold nanoparticles.

FIG. 31 shows the Rf values when rice-shaped ZAIS nanoparticles (particle diameter 19 nm) are developed using the gold nanoparticle-containing layers of various shapes shown in FIG. 30 as the plasmon structure-containing layer and irradiated with LED light with a wavelength of 610 nm. It is a graph which shows the relationship between and the irradiation light intensity. The horizontal axis in FIG. 31 is the intensity of light. The vertical axis in FIG. 31 is the Rf value.

As shown in FIG. 31, there was no significant difference in light intensity dependence between octahedral gold nanoparticles with a particle diameter of 75 nm and spherical gold nanoparticles with a particle diameter of 82 nm. No matter which particles were used, ZAIS nanoparticles were captured in the gold nanoparticle-containing layer at a light intensity of about 1 W/cm ² or higher. On the other hand, when spherical gold nanoparticles with a smaller particle diameter of 12 nm were used, ZAIS nanoparticles were not captured in the gold nanoparticle-containing layer at any light intensity. It is suggested that the size of the plasmon structure is greatly involved in the success or failure of capturing ZAIS nanoparticles.

B. Silver nanoparticles (plasmon structure)
1. Experimental method 1-1. Production of silver nanoparticles 4.8 mL of an aqueous solution containing 2 mM NaBH ₄ and 2 mM trisodium citrate was prepared. After holding this aqueous solution at 60° C. for 30 minutes, 0.2 mL of a 1.17 mM AgNO ₃ aqueous solution was added. This mixed solution was heated to 90° C., a 0.01M NaOH aqueous solution was added, and the mixture was heated for 20 minutes. The pH of the NaOH aqueous solution was 10.5. In this way, silver nanoparticles with a particle size of 10 nm were obtained.

Silver nanoparticles were then applied to the octadecyl group-modified reversed-phase silica gel TLC plate and dried.

2. Experimental results 2-1. Light intensity dependence FIG. 32 is a graph showing the diffuse reflection spectrum of a plasmonic structure-containing layer using silver nanoparticles. The horizontal axis in FIG. 32 is the wavelength of light. The vertical axis in FIG. 32 is the value of the Kubelker-Munk function. A surface plasmon resonance peak was observed between approximately 400 nm and 600 nm. In order to optically excite this surface plasmon resonance peak, a blue LED capable of emitting monochromatic light with a peak wavelength of 460 nm was used as a light irradiation section.

Figure 33 is a photograph of a stationary phase member after rice-shaped ZAIS nanoparticles (19 nm) were developed using silver nanoparticles as a plasmon structure and irradiating the part with blue LED light with a wavelength of 460 nm at various light intensities. It is. As shown in FIG. 33, as the intensity of light increases, the distance the ZAIS nanoparticles move becomes smaller, and the ZAIS nanoparticles can be captured more effectively.

FIG. 34 is a graph showing the relationship between the irradiation light intensity and the Rf value of the rice-shaped ZAIS nanoparticles in FIG. 33. The horizontal axis in FIG. 34 is the intensity of blue LED light with a wavelength of 460 nm. The vertical axis in FIG. 34 is the Rf value. As shown in FIG. 34, when the light intensity is set to 0.30 W/cm ² or more, the silver nanoparticle-containing layer, which is a plasmon structure, can capture ZAIS nanoparticles.

2-2. Wavelength dependence of irradiated light Figure 35 shows the wavelength (λirrad) of monochromatic light irradiated to the silver nanoparticle-containing layer, which is the plasmonic structure-containing layer, and the capture of rice-shaped ZAIS nanoparticles (19 nm) in the silver nanoparticle-containing layer. It is a graph showing the relationship with the required minimum light intensity (Imin). The horizontal axis in FIG. 35 is the wavelength of light. The vertical axis in FIG. 35 is the minimum light intensity required to trap ZAIS nanoparticles in the gold nanoparticle-containing layer. As shown in FIG. 35, when silver nanoparticles are used as the plasmonic structure, as the wavelength of irradiation light becomes shorter from 820 nm to 460 nm, the minimum light intensity required to capture ZAIS nanoparticles becomes smaller.

In the diffuse reflection spectrum of the silver nanoparticle-containing layer shown in FIG. 32, the value of the Kubelker-Munk function increases as the wavelength becomes shorter from 820 nm to 460 nm. For these reasons, ZAIS nanoparticles can be captured with lower light intensity by using irradiation light with a short wavelength that can optically excite surface plasmon resonance more effectively. That is, when irradiating light of 820 nm, which is a wavelength region where the value of the Kubelker-Munk function is small near the tail of the peak of surface plasmon resonance, ZAIS nanoparticles may be captured unless the intensity of the light is sufficiently large. I can't.

2-3. Particle size dependence of nanostructures that are separation targets When using a silver nanoparticle-containing layer as a plasmonic structure-containing layer, quantum dots (ZAIS nanoparticles or AgInGaS nanoparticles) of various particle sizes are deployed to form a separation target. We investigated the relationship between particle size and capture efficiency of quantum dots. The ZAIS nanoparticles and AgInGaS nanoparticles used were produced in the same manner as when gold nanoparticles were used as the plasmonic structure-containing layer.

Using silver nanoparticles as a plasmon structure, quantum dots of various sizes were developed while irradiating blue LED light with a wavelength of 460 nm.

FIG. 36 is a graph showing the relationship between the particle diameter of the quantum dots used and the Rf value. The horizontal axis in FIG. 36 is the particle diameter of the quantum dots that are the separation targets. The vertical axis in FIG. 36 is the Rf value. As shown in FIG. 36, when the particle size is 7.8 nm or more, the plasmonic structure can capture ZAIS nanoparticles or AgInGaS nanoparticles.

C. ITO particles (plasmonic structure)
1. Experimental Method A stationary phase support plate was prepared by applying ITO particles (manufactured by Aldrich) as a plasmonic structure-containing layer to the above-mentioned octadecyl group-modified reversed-phase silica gel TLC plate and drying it. The particle diameter of the ITO particles was 100 nm. The number density of ITO particles in the plasmonic structure-containing layer was 1.1×10 ¹³ particles/cm ³ . Rice-shaped ZAIS nanoparticles with a particle diameter of 19 nm were used as the nanostructures serving as separation targets.

FIG. 37 is a graph showing the diffuse reflection spectrum of the ITO particle-containing layer. The horizontal axis in FIG. 37 is the wavelength of light. The vertical axis in FIG. 37 is the Kubelker-Munk function. As shown in FIG. 37, a broad surface plasmon resonance peak exists in the near-infrared region of 600 nm or more. Furthermore, the wavelength of 820 nm is at the base of the surface plasmon resonance peak. However, the value of the Kubelker-Munk function at 820 nm in FIG. 37 is comparable to the value of the Kubelker-Munk function at the irradiation wavelength in FIGS. 23 and 32. Therefore, by irradiating near-infrared monochromatic light with a wavelength of 820 nm, the surface plasmon resonance of the ITO particles is sufficiently effectively photoexcited.

2. Experimental results Figure 38 shows rice-shaped ZAIS nanoparticles (particle diameter: 19 nm) being irradiated with 820 nm monochromatic light extracted from Xe lamp light using a plasmon structure-containing layer supporting ITO particles as a plasmon structure. This is a photograph of the stationary phase supporting plate after development. As shown in FIG. 38, when no light was irradiated, the ZAIS nanoparticles were hardly captured by the ITO particle-containing layer and moved to the upper part of the stationary phase support plate. However, when the light intensity was 0.31 W/cm ² , the moving distance of the ZAIS nanoparticles was shorter than when no light was irradiated. When the light intensity was 0.45 W/cm ² or more, rice-shaped ZAIS nanoparticles were captured in the ITO particle-containing layer portion of the stationary phase support plate.

FIG. 39 is a graph showing the relationship between light intensity and Rf value when rice-shaped ZAIS nanoparticles (particle diameter 19 nm) are expanded while irradiating monochromatic light of 820 nm using ITO particles as a plasmon structure. . The horizontal axis in FIG. 39 is the intensity of light. The vertical axis in FIG. 39 is the Rf value of the rice-shaped ZAIS nanoparticles. As shown in FIG. 39, if the stationary phase support plate is irradiated with light having an intensity of about 0.45 W/cm ² or more, the rice-shaped ZAIS nanoparticles can be captured in the ITO particle-containing layer portion. In this way, not only metal nanoparticles but also nanoparticles made of metal compounds such as metal oxides can be used as the plasmonic structure.

D. Light capture when using an organic compound as a nanostructure that is a separation target 1. Experimental Method A stationary phase support plate was manufactured by supporting the above-mentioned octadecyl group-modified reversed-phase silica gel TLC plate with gold nanoparticles as a plasmonic structure-containing layer. The particle size of the gold nanoparticles was 12 nm. The number density of gold nanoparticles was 3.5×10 ¹³ pieces/cm ³ . Fluorescent polystyrene beads (manufactured by Thermo SCIENTIFIC) with a particle size of 47 nm were used as the target nanostructure. The developing solvent was methanol.

2. Experimental Results FIG. 40 is a photograph of a stationary phase support plate after polystyrene beads were developed as nanostructures with methanol while being irradiated with LED light having a wavelength of 610 nm at various light intensities. As shown in FIG. 40, when the light intensity is increased, the gold nanoparticle-containing layer can capture the polystyrene beads. When the light intensity was 0.63 W/cm ² , most of the polystyrene beads could be captured on the top of the gold nanoparticle-containing layer. When the light intensity was 0.88 W/cm ² , all the polystyrene beads could be captured in the center of the gold nanoparticle-containing layer.

FIG. 41 is a graph showing the relationship between the moving distance of polystyrene beads and the intensity of irradiated light when developed with methanol from the position (origin) where polystyrene beads were dropped and fixed on TLC. The horizontal axis in FIG. 41 is the intensity of light. The vertical axis in FIG. 41 is the moving distance (cm) of the polystyrene beads from the origin. As shown in FIG. 41, if the stationary phase supporting plate is irradiated with light of sufficient intensity, the plasmonic structure can capture the polystyrene beads.

E. Summary of the experiment By irradiating the gold nanoparticle-containing layer, which is a plasmon structure, with light of sufficient intensity at a wavelength that can excite the surface plasmon resonance of the gold nanoparticle-containing layer, the gold nanoparticle-containing layer is able to absorb inorganic nanoparticles (quantum dots) in the mobile phase. ) was able to be captured. As the light intensity increases, the ability of the gold nanoparticle-containing layer to capture inorganic nanoparticles tends to increase. Furthermore, the smaller the particle size of the inorganic nanoparticles, the more difficult it tends to be for the gold nanoparticle-containing layer to capture the inorganic nanoparticles.

Furthermore, even when the intensity of light was not sufficient to capture inorganic nanoparticles, the movement speed of inorganic nanoparticles in the mobile phase could be slowed down. As a result, the stopping position of the inorganic nanoparticles had a smaller Rf value than when no light was irradiated.

Plasmonic structures are not limited to metal nanoparticles. The material of the plasmon structure is not particularly limited as long as it is a particle capable of exciting surface plasmon resonance, such as gold nanoparticles, silver nanoparticles, and ITO particles.

A nanostructure that is a capture target or a separation target may be an inorganic compound or an organic compound. For example, it may be a conductor, a semiconductor, or an insulator. Even with highly insulating materials such as polystyrene beads, an attractive force is generated between the plasmonic structure and the nanostructure due to the microscopic localized electric field generated by the plasmonic structure.

(Additional note)
The separation device in the first aspect includes a stationary phase member having a stationary phase, a development tank capable of accommodating the stationary phase member and the mobile phase, and a light irradiation unit that irradiates light toward the stationary phase member. The stationary phase includes an adsorbent and a plasmonic structure-containing layer in which a plasmonic structure is arranged on the adsorbent. The stationary phase member can be supplied with a mobile phase that includes nanostructures and can move the mobile phase along the stationary phase.

In the separation device according to the second aspect, the light irradiation unit irradiates the plasmon structure with light capable of exciting surface plasmon resonance.

In the separation device according to the third aspect, the plasmon structure captures the nanostructure during the period in which the light irradiation section is irradiating the stationary phase member with light, or captures the nanostructure in the mobile phase. Slows down the movement speed of.

In the separation device according to the fourth aspect, the stationary phase has a first carrier layer and a second carrier layer that do not contain a plasmonic structure but contain an adsorbent. The plasmonic structure-containing layer is arranged at a position between the first carrier layer and the second carrier layer.

In the separation device according to the fifth aspect, the plasmon structure is a metal nanoparticle having a surface plasmon resonance peak.

In the separation device according to the sixth aspect, the plasmon structure is a metal compound nanoparticle having a surface plasmon resonance peak.

In the separation device according to the seventh aspect, the nanostructures are nanoparticles made of an inorganic compound or an organic compound.

The stationary phase member in the eighth aspect has a stationary phase. The stationary phase includes an adsorbent and a plasmonic structure-containing layer in which a plasmonic structure is arranged on the adsorbent. The stationary phase member can be supplied with a mobile phase that includes nanostructures and can move the mobile phase along the stationary phase.

In the stationary phase member according to the ninth aspect, the plasmon structure captures the nanostructure during the period when the stationary phase member is irradiated with light, or the plasmon structure captures the nanostructure at a speed of movement of the nanostructure in the mobile phase. to slow down.

In the stationary phase member according to the tenth aspect, the stationary phase has a first carrier layer and a second carrier layer that do not contain a plasmonic structure but contain an adsorbent. The plasmonic structure-containing layer is arranged at a position between the first carrier layer and the second carrier layer.

In the stationary phase member according to the eleventh aspect, the plasmon structure has a surface plasmon resonance peak.

In the method for separating nanostructures in the twelfth aspect, a liquid chromatograph is used that uses a liquid as a mobile phase and a solid as a stationary phase. A stationary phase containing a plasmon structure capable of exciting surface plasmon resonance is used. A liquid containing nanostructures is used as a mobile phase. Surface plasmon resonance is excited in the plasmon structure by irradiating the plasmon structure with light. The plasmonic structure traps the nanostructure or slows down the movement speed of the nanostructure in the mobile phase.

In the method for separating nanostructures in the thirteenth aspect, surface plasmon resonance is excited in the plasmon structure by irradiating the plasmon structure with light, thereby generating an attractive force between the plasmon structure and the nanostructure. let

DESCRIPTION OF SYMBOLS 1000...Separation device 1100...Light irradiation part 1200...Development tank 100...Stationary phase member 110...Substrate 120, 140...Carrier layer 130...Plasmon structure-containing layer L1...Liquid P1...Gold nanoparticles N1...Inorganic nanoparticles

Claims (13)

a stationary phase member having a stationary phase;
a development tank capable of accommodating the stationary phase member and the mobile phase;
a light irradiation unit that irradiates light toward the stationary phase member;
has
The stationary phase is
an adsorbent;
a plasmonic structure-containing layer in which a plasmonic structure is arranged on the adsorbent;
The stationary phase member is
said mobile phase comprising nanostructures;
A separation device comprising being able to move the mobile phase along the stationary phase. The separation device according to claim 1,
The light irradiation section is
A separation device comprising irradiating the plasmon structure with light capable of exciting surface plasmon resonance. The separation device according to claim 1 or 2,
The plasmonic structure is
During the period in which the light irradiation unit irradiates the stationary phase member with light,
A separation device comprising capturing the nanostructures or slowing down the rate of movement of the nanostructures in the mobile phase. In the separation device according to any one of claims 1 to 3,
The stationary phase is
comprising a first carrier layer and a second carrier layer that do not contain the plasmonic structure and contain the adsorbent;
The plasmonic structure-containing layer is
A separation device comprising: a separation device disposed at a position between the first carrier layer and the second carrier layer. In the separation device according to any one of claims 1 to 4,
The plasmonic structure is
A separation device comprising metal nanoparticles with a surface plasmon resonance peak. In the separation device according to any one of claims 1 to 4,
The plasmonic structure is
A separation device comprising metal compound nanoparticles having a surface plasmon resonance peak. In the separation device according to any one of claims 1 to 6,
The nanostructure is
A separation device comprising nanoparticles made of inorganic or organic compounds. In a stationary phase member having a stationary phase,
The stationary phase is
an adsorbent;
a plasmonic structure-containing layer in which a plasmonic structure is arranged on the adsorbent;
The stationary phase member is
can be supplied with a mobile phase containing nanostructures, and
A stationary phase member, the stationary phase member being capable of moving the mobile phase along the stationary phase. The stationary phase member according to claim 8,
The plasmonic structure is
During the period when the stationary phase member is irradiated with light,
A stationary phase member comprising capturing the nanostructures or slowing down the rate of movement of the nanostructures in the mobile phase. The stationary phase member according to claim 8 or 9,
The stationary phase is
comprising a first carrier layer and a second carrier layer that do not contain the plasmonic structure and contain the adsorbent;
The plasmonic structure-containing layer is
A stationary phase member disposed between the first carrier layer and the second carrier layer. The stationary phase member according to any one of claims 8 to 10,
The plasmonic structure is
A stationary phase member having a surface plasmon resonance peak. Using a liquid chromatograph that uses a liquid as a mobile phase and a solid as a stationary phase,
Using the stationary phase containing a plasmon structure capable of exciting surface plasmon resonance,
Using a liquid containing nanostructures as the mobile phase,
Exciting the surface plasmon resonance in the plasmon structure by irradiating the plasmon structure with light,
A method for separating nanostructures, comprising trapping the nanostructures in the plasmonic structure or slowing down the movement speed of the nanostructures in the mobile phase. The method for separating nanostructures according to claim 12,
Exciting the surface plasmon resonance in the plasmon structure by irradiating the plasmon structure with light,
A method for separating nanostructures, comprising generating an attractive force between the plasmonic structure and the nanostructure.

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