JP2002071645A - Magnetic susceptibility measuring method and device for suspended magnetic particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the magnetic susceptibility of particles by causing the magnetic migration of magnetic particles in a solution in a capillary in a large magnetic field gradient generated in a region with the spacing of micro width of about 100 μm to several 100 μm, using a micro magnetic pole piece. SOLUTION: This magnetic susceptibility measuring method for the magnetic particles is characterized by measuring the magnetic migration speed and particle diameter of magnetic particles of unknown magnetic susceptibility suspended in a solvent in the cell installed in the magnetic field gradient, while measuring the magnetic migration speed and particle diameter of magnetic particles of known magnetic susceptibility suspended in the solvent in the cell installed in the magnetic field gradient, then determining magnetic field distribution on the basis of the measured values of the magnetic migration speed and particle diameter of the particles of known magnetic susceptibility, and determining the magnetic susceptibility of the individual particles on the basis of the determined magnetic field distribution and the measured values of the magnetic migration speed and particle diameter of the particles of unknown magnetic susceptibility.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the magnetophoretic velocity of particles in a solvent in a cell such as a capillary installed in a magnetic field gradient and the radius of the particles. The present invention relates to a fine particle magnetophoretic susceptibility measuring method and apparatus for determining the susceptibility of fine particles on the basis of the method.

[0002]

2. Description of the Related Art Conventionally, the magnetic susceptibility of a certain amount of solid or liquid is measured by using a Guy's magnetic balance. However, there has been a method of measuring the magnetic susceptibility of each fine particle. Absent. According to the present invention, deviation of magnetic susceptibility due to fine particles or distribution of magnetic susceptibility can be known. Today, in the field of material industry in which high quality is pursued, the homogeneity of fine particle material is a problem. The present invention aims to provide a unique measurement that addresses these problems.

[0003]

SUMMARY OF THE INVENTION The present invention uses a small permanent magnet or a small pole piece magnetized by an external magnetic field.
A large magnetic field gradient is generated in a region with a small width of about 100 micrometers to several hundred micrometers, and the generated magnetic field gradient is used to cause the magnetic fine particles in the solution in the cabary to cause magnetophoresis. The present invention relates to a method and an apparatus for measuring the magnetophoretic velocity and the particle diameter of a magnetic particle, and for determining the magnetic susceptibility of the fine particle based on the measured values of the magnetophoretic velocity and the particle diameter of the magnetic fine particles.

More specifically, the method of the present invention for determining the magnetic susceptibility of a fine particle from the measurement of the migration speed of the magnetophoresis is based on the method of determining the magnetic susceptibility of the fine particle suspended in a solvent in a cell installed in a magnetic field gradient. The particle size is measured, and the magnetic susceptibility of each fine particle is determined based on the measured magnetophoretic velocity and particle size of the fine particles, the viscosity and magnetic susceptibility of the medium, and the measured magnetic gradient.

Further, another method for determining the magnetic susceptibility of magnetic fine particles from the measurement of the migration speed of the magnetophoresis according to the present invention is a magnetic fine particle of unknown magnetic susceptibility suspended in a solvent in a cell placed in a magnetic field gradient. Of the magnetic fine particles of known susceptibility suspended in a solvent in a cell placed in a magnetic field gradient. Determine the magnetic field distribution based on the measured values of the magnetophoretic velocity and particle size of the determined magnetic field distribution,
The magnetic susceptibility of each fine particle is determined based on the measured values of the magnetophoretic velocity and the particle size of the fine particles of unknown magnetic susceptibility.

When the magnetic fine particles are dissolved in a solvent,
The magnetic susceptibility is corrected based on the solubility of the fine particles in the solvent. Further, it is preferable to use a solvent saturated with a substance constituting the fine particles as the solvent containing the predetermined magnetic fine particles. The reason is that it is possible to prevent the magnetic fine particles from dissolving in the solvent and changing the particle diameter.

An apparatus for measuring magnetic susceptibility of magnetic fine particles of the magnetophoresis system according to the present invention is provided in a pair of magnets for forming a minute magnetic field and in a minute magnetic field space formed between the pair of magnets, and is used to remove the magnetic particles. A cell filled with a solvent containing, and a measuring device for measuring the magnetophoretic velocity of the magnetic fine particles in the solvent in the cell during the application of a magnetic field,
It comprises a measuring device for measuring the radius of the fine particles, and an arithmetic unit for determining the magnetic susceptibility of the magnetic fine particles based on the measured magnetophoretic velocity and particle size of the fine particles, the viscosity and the magnetic susceptibility of the medium, and the measured magnetic gradient.

A measuring device for measuring the magnetophoretic velocity of the magnetic fine particles in the solvent in the cell during the application of a magnetic field and a measuring device for measuring the radius of the fine particles, a microscope for observing the fine particles in the cell,
A CCD camera that converts an image obtained by a microscope into an electric signal, a recorder that records the electric signal converted by the CCD camera, and an analyzer that analyzes the recorded electric signal can be provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. First, the background of the present invention will be described. The present inventor has proposed a method in which a pair of small permanent magnets or a pair of small magnetic pole pieces magnetized by a permanent magnet, an electromagnet, and a superconducting magnet are placed in a fixed distance of about 100 micrometers to several hundred micrometers, for example, about 500 micrometers. When a staff member is arranged with a gap, and the magnetic field lines pass from one pole piece to the other pole piece through the gap, the direction of the magnetic field lines is located outward from the end between the magnets of the gap, for example, at a position of about 100 micrometers. It has been found that since there is a reversal point (magnetic flux density B = 0), a large magnetic gradient is generated on both sides of this point, especially on the inside of the air gap from this point. It has been found that the value of B (dB / dx) showing its magnitude easily meets 400 T2 / m. This is the strength that can usually be generated by superconducting magnets.

Through this gap, a square glass gallery having a cross section of about 100 μm × 100 μm is installed, and an aqueous solution or non-aqueous solution containing fine particles is introduced to stop the flow. . Depending on the magnetic susceptibility difference between the solvent in the capillary and the particles, the particles
Electrophoresis in the direction approaching or away from the point of = 0. The particle size and migration speed of the magnetic fine particles at this time were determined by CCD
Measure with a microscope having a camera and video recording system. At this time, the micrometer-order distribution of the magnetic field strength in the gap can be determined by measuring the migration speed using fine particles having a known particle size and magnetic susceptibility. With a Gauss meter that is generally widely used, it is impossible to determine a magnetic field distribution in such a minute portion.

Next, the electrophoretic velocity is measured for the fine particles of unknown magnetic susceptibility in the medium of known magnetic susceptibility, and the magnetic susceptibility of the fine particles can be determined from the relationship between the position and the electrophoretic velocity. Since a thin capillary and a microscope are used, it is possible to determine the magnetic susceptibility of fine particles having a size of about several micrometers. The state of the fine particles may be any of a liquid, a solid, and a gas as long as the shape and size can be determined. Therefore, the sample can be applied to any sample such as a biological sample containing fine particles, an environmental sample, and a functional material. Since a sample can be continuously fed into the cabary using a micro syringe or a micro pump, a large number of samples can be measured quickly.

Embodiment

Hereinafter, the experiment, technical analysis, and theoretical configuration that led to the present invention will be described in more detail. (1) Force applied to magnetic particles and magnetophoretic velocity in an inhomogeneous magnetic field When a small permanent magnet or a pair of small magnetic pole pieces magnetized in a magnetic field is arranged with a gap of about 100 to 400 micrometers A magnetic field gradient generated between the ends of the magnets in the gap near the ends was 100 micrometers × 100.
A glass capillary having a square cross section of about a micrometer is installed, and an aqueous or non-aqueous solvent containing fine particles is introduced into the glass capillary. See FIG. 1 (a) and FIG. 1 (b). In this case, if the longer pole piece (for example, an iron piece) is attached perpendicularly to the magnet as shown in the figure, the pole piece gathers the lines of magnetic force scattered by the magnet and generates a stronger magnetic field at its tip. At this time, a large magnetic field gradient is generated along the x-axis of the iron piece (the central axis of the capillary), and the magnetic buoyancy generated in this region is used as a driving force for electrophoresis. Then, the end of the pole piece from which the flow flows was set to 0. In the figure, 1 and 1 are a pair of magnets opposed to each other, MP is an iron piece mounted perpendicularly to the facing surface of each magnet and facing inward with the above-mentioned gap, and C is a gap between the iron pieces MP and MP. The glass capillaries placed are shown. When the solvent is weakly diamagnetic and the fine particles contain a ferromagnetic material, a magnetic force acts on the fine particles from the point of B = 0, which is about 100 micrometers outside the magnet end, into the gap of the magnet (FIG. 1 ( c)), a constant velocity motion is generated by a force different from the viscous force that opposes this. When the solvent is paramagnetic and the fine particles are weakly diamagnetic, the direction of electrophoresis is directed to the point B = 0 from the gap of the magnet due to magnetic buoyancy. Since there is a magnetic gradient between the magnetic poles, the movement at this time does not migrate linearly in the direction of the capillary wall, but moves in an arc, and finally contacts the capillary wall.

(2) A substance placed in an inhomogeneous magnetic field:
It receives a magnetic force due to its magnetism. If the substance is paramagnetic, it receives a force in the direction of a strong magnetic field; if it is diamagnetic, it receives a force in the direction of a weak magnetic field. FIG. 2A shows a state in which paramagnetic fine particles are attracted to a magnetic field having a strong magnetic field. At this time, considering the capillary axis direction (hereinafter referred to as the x direction), the force that the magnetic particles receive in the non-uniform magnetic field, that is, the magnetic force, is approximately expressed by the following equation.

(Equation 1) Here, V is the volume of the particle (m ³ ), μ ₀ is the magnetic permeability of vacuum (Ns ² c ⁻² ), χ is the volume susceptibility of the particle (−), H is the external magnetic field (Am ⁻¹ ), dH / Dx is the magnetic field gradient (Am ^-2 ).
Since the relationship of B = μμ ₀ H holds between the magnetic field H and the magnetic flux density B (T), if μ = 1, the expression (1) can be rewritten as follows.

(Equation 2) Such a magnetic force also acts on particles in a medium in an inhomogeneous magnetic field. In this case, since the magnetic force also acts on the medium, the force generated by the magnetic force must be considered. In other words, two forces as shown in FIG. 2B act on the particles. One is the magnetic force F _p acting on the particles themselves, another equal power and magnitude acting on the medium of the same volume and particles, orientation opposite forces, magnetic buoyancy F _f. Thus, the force F _m for receiving the particles in the medium from (2),

(Equation 3) Becomes Here, χ _p and _{ｆ f} are the volume susceptibilities of the particles and the medium, respectively. Next the other hand, when the particles migrate through the medium by the magnetic force, the particles are subjected to fluid resistance force F _v in the opposite direction to the direction of electrophoresis, but if the particles are spherical, the size of the force by Stokes Law It is represented as

(Equation 4) Here, η is the viscosity of the medium (Pas), r is the particle radius (m),
v is the velocity of the particle (ms ^{- 1} ). In the electrophoresis phenomenon we deal with, the mass and acceleration of the particles are sufficiently small, so that _Fm and _Fv
The following equation is obtained as the migration speed of the particles, assuming that the particles are always migrating while being balanced.

(Equation 5) As is clear from equation (5), the migration speed is determined by the position of the particles. Further, in order to increase the migration speed of the particles, the difference between the magnetic susceptibility of the particles and the medium is increased or B (d
B / dx) needs to be increased. In our experiments, for example, the magnetic difference between the particles and the medium is increased by using a manganese chloride aqueous solution of a ferromagnetic solution as the medium, and the particles swim mainly by magnetic buoyancy.

(2) Measurement of Magnetophoretic Velocity of Magnetic Particles
It measured using the following method and apparatus. (2-1) Sample A droplet of an easily available manganese chloride aqueous solution having a high magnetic susceptibility was selected as a target of the magnetophoretic velocity analysis. Immediately before the start of the experiment, 30 μl of a 0.001 to 1.0 mol dm ⁻³ aqueous solution of manganese chloride was added to a screw tube containing 5 ml of ethyl benzoate as a medium, and the mixture was ultrasonically dispersed in droplets to obtain a sample. . Ethyl benzoate used was one saturated with water and one not. A manganese chloride aqueous solution of 0.02 to 2.5 mol dm ^-3 was used as a sample for measuring magnetic susceptibility.

(2-2) Measuring Apparatus (2-2-1) Magnetophoretic Velocity Measuring Apparatus and Experimental Conditions The magnetophoretic velocity of the fine particles was measured using a magnetophoretic velocity measuring apparatus shown in FIG. The magnetophoretic velocity measuring device includes a pair of magnets 1 having a capillary C as a cell disposed therebetween.
A microscope 2 for observing magnetophoresis of fine particles, an irradiation light 3 for irradiating light to the capillary, a CCD camera 4 for converting a light signal of an image obtained by the microscope into an electric signal, a monitor device 5, a microscope, A video tape recorder 6 for recording the image obtained in step 1 as an electric signal, and an arithmetic unit (personal computer) 7. Further, an XY stage 8 for adjusting the position of the cell in the X and Y directions on a horizontal plane is provided.

The cell containing the sample liquid has an inner size of 100 μm.
× 100 μm, external 300 μm × 300 μm square capillary (Polymicro Technology)
ges, Square Flexible Fused
Silica Capillary Tubing)
Was used. The above-mentioned sample solution was put in the above-mentioned capillary (20 cm in length) and placed between two magnets as shown in FIG. The size of the magnet is 16.85 mm x 19.6 mm x 2.9 m
m Nd-Fe-B magnet (Sumitomo Special Metals, NEOMA
X) was used. The measurement area of the migration speed was 200 μm inside the magnet end where the magnetic field gradient was large. Since it is necessary to increase the value of B (dB / dx) in order to obtain a high migration speed, the distance between the two magnets was set to 400 μm using an aluminum spacer. The two magnets were fixed to an aluminum magnet holder, and the position of the magnet holder was adjusted by an XY stage. The electrophoretic behavior of polystyrene particles was measured using a microscope (Chuo Seiki), CCD
The images were observed with a camera (ELMO, CN42H) and a monitor, recorded on a video, and the images were taken into a personal computer and analyzed.

(2-2-2) Measurement of magnetic susceptibility For measuring magnetic susceptibility, a magnetic susceptibility measuring instrument (Sherwood) was used.
Scientific LTD, MSB-AUTO) was used.

(2-3) Magnetic field analysis software "SUPERM"
Simulation by OMENT "Calculating the magnetic field generated by a coil or magnet and the generated torque are called magnetic field analysis. These calculation methods include a magnetic moment method, a finite element method, and a boundary element method.
"SUPERMOM" used for magnetic field analysis in the present invention
ENT '(H. Sekiya, 1998) is a program of the magnetic moment method, which is a product that enables a magnetic field analysis, which was conventionally used for a large computer, to be executed on a personal computer.

Although the approximate magnetic field produced by the magnet can be calculated by this "SUPERMOMENT", the magnetic field intensity around the magnet cannot be calculated exactly. The reason is that the properties and shapes of the actual magnets are not completely perfect, so their effects appear in experimental systems. In particular, in a very microscopic space as dealt with in the present invention, the roundness of the end of the magnet has a great influence on the formation of the magnetic field. However, in order to predict a magnetic field in a small space where a magnetic field measuring device such as a Gauss meter cannot be used, a magnetic field analysis by "SUPERMOMENT" is a very useful means.

The magnet for simulation is 17 mm ×
19mm x 3mm NeFeB40 magnet (Nd-Fe
-Same as B magnet). The X axis was 0 at the magnet end, the inside direction of the magnet was positive, and the Z axis was 0 at the center of the magnet. The distance between the magnets is 400 mm as in the experiment. (3) Experimental results and discussion (3-1) Shape of magnetic field and migration behavior Fig. 3 (a) shows the shape of the magnetic field obtained from the simulation. FIG. 3B shows the relationship between the magnet and the capillary, and the X axis and the Z axis. From this, the outline of B (dB / dx) is derived, as shown in FIGS. 5 (a) and 5 (b). This figure 5
Looking at (a), FIG. 5 (b) and equation (5), x = 200 μm
It can be seen that the speed becomes the largest near m. Also, it can be seen that the electrophoresis is performed so as to be attracted to the magnet closer in the z direction. FIG. 6 is a diagram in which the image of the droplet during the electrophoresis is taken into the personal computer every second and superimposed, and moves as expected in the simulation. FIG. 7 shows the measured velocity of the droplet in the x direction at 0 to 300 μm. As can be seen from this graph, the velocity changes depending on the position, reflecting the shape of the magnetic field, and reaches a maximum near x = 200 μm. Further, it can be seen that it depends on the particle size and concentration.

(3-2) Dependence of bag size on x around 200 μm As can be seen from equation (5), the velocity v _x property is proportional to the square of the particle size r. FIG. 8 is a plot of v _x versus r ² at x = 200 μm when a 0.06 mol dm ⁻³ manganese chloride aqueous solution was used for the droplets, and a proportional relationship was obtained.

(3-3) Relationship between Δx and manganese concentration FIG. 9 shows the result of examining the relationship between ^Δx and the manganese concentration [Mn ²⁺ ] using a magnetic balance. From this graph △ x
It has been found that the following equation is satisfied between [Mn ²⁺ ] and [Mn ²⁺ ].

(Equation 6) (3-4) Concentration Dependence of Vx near x = 200 μm It can be seen from equations (5) and (6) that Δx is also proportional to [Mn ²⁺ ].

(Equation 7)

To confirm this, FIG. 10 is a graph in which v _x / r ² is plotted against [Mn ²⁺ ]. The graph shows that v _x / r ² depends on [Mn ²⁺ ], but does not seem to be a simple proportional relationship. Equation (7) shows B (dB) at x = 20 μm experimentally obtained.
The theoretical value obtained by substituting / dx) is the oblique straight line in FIG. Considering why this was the case,
30 μl of manganese chloride aqueous solution in 5 ml of ethyl benzoate
Because of the dispersion, it was considered that water in the droplets was dissolved in ethyl benzoate, and that [Mn ²⁺ ] was increased.

(3-5) Ethyl benzoate saturated with water
As a result of the experiment using²⁺] Is increasing
To determine whether or not ethyl benzoate saturated with water
The experiment was performed as in FIG._x/ R ^TwoTo [M
n²⁺FIG. 1 is plotted against
It is one. New plots are in good agreement with theoretical values
Is shown. Therefore, I think that the water had melted out
No doubt.

[0025]

Embodiments of the present invention will be described below. (1) Fine Particles, Magnetic Chemical Species In the present invention, the fine particles containing a magnetic chemical species can be a solvent such as water as in the above experiment,
Examples of the solvent include non-aqueous solvents having a density close to 1 and immiscible with water, solids such as polymers, ceramics, fine particles suspended in the environment, and fine particles of living organisms. The magnetic species is manganese (II) And transition metal ions such as iron (II) and the like, rare earth metal ions, and compounds containing them. The fine particles having a particle size of about 0.1 to 100 microns are particularly suitable for the present invention, and the concentration of the magnetic chemical species used as a solvent or the like is 10 μm. ^The position is preferably from ^-5 to 1 moldm- ³ .

(2) Solvent Water and a transparent liquid other than water can be used as a solvent for dispersing the fine particles. Preferred combinations of the fine particles and the fine particle suspension solvent include, for example, an aqueous solution and ethyl benzoate, 2-fluorobenzene, anisole and the like. The concentration of the fine particles to be dispersed in the solvent is not particularly limited, but may be 1 × 10 ⁻⁵ to 1 mol d
m- ³ is particularly suitable for the magnetophoretic susceptibility measurement method of the present invention. When the substance forming the fine particles is dissolved in the solvent, it is possible to perform the same measurement using a solvent in which the substance is saturated, correct the calibration curve, and perform the magnetophoretic susceptibility measurement of the present invention. it can. In addition, since the migration direction of the fine particles differs depending on whether the magnetic susceptibility is larger or smaller than the medium, it can be determined from the migration direction whether the contained substance is diamagnetic or ferromagnetic. The idea of determining the concentration from the migration speed can be applied to other electrophoresis methods.

(3) Cell As the cell, a capillary tube, a glass cell, or a plastic cell can be used. The dimensions of the capillary are not particularly limited. Is preferred. (4) Others In addition, the present method is applicable to a solution in which an aqueous solution is dispersed in an organic solution, or a solution in which an organic solution is dispersed in an aqueous solution.

[0028]

EXAMPLES (Example 1) In order to estimate the value of B (dB / dx) generated by the arrangement of the magnet and the iron piece in FIG. 1, the measurement of the magnetophoretic velocity was performed. The sample solution was a 0.6 M aqueous manganese chloride solution containing polystyrene particles having a particle size of 3 μm, and the migration speed of the polystyrene particles was measured by a microscope. Magnet 1
Used was an Nd-Fe-B magnet, and an iron piece as a pole piece MP having a size of 3 × 1 × 7 mm and a purity of 99.8% was used. An aluminum spacer having a thickness of 14.4 mm was used to keep the distance between the two magnets. When the long side of the iron piece is perpendicular to the magnet as shown in the figure, the iron piece collects the lines of magnetic force scattered by the magnet and acts as a pole piece, generating a stronger magnetic field at its tip. At this time, since a large magnetic field gradient is generated along the x-axis (the central axis of the capillary) of the iron piece, the magnetic buoyancy generated in this region was used as a driving force for swimming. Also, the x-axis here indicates that the direction of the flow is a positive direction, and the end of the iron piece from which the flow flows is 0.
I took it. FIGS. 12 and 13 show the migration speed of 3 μm polystyrene particles in a 0.6 M manganese chloride aqueous solution and the B (dB / dx) expected from the results, respectively. Here, the distance between the broken lines in the drawing represents the width of the iron piece. As can be seen from these graphs, the phenomenon of agglomeration of particles was not observed. Maximum value of migration speed is x = 95
In μm, it is -62 μms ² , which is about four times the maximum velocity of 3 μm polysterene particles without using iron pieces. In other words, the use of iron pieces resulted in a magnetic buoyancy about four times greater than the conventional magnet arrangement. This means that the maximum value of B (dB / dx) in FIG.
It is clear from the fact that it is 1,800 T ² / m. (Example 2) Measurement of volume susceptibility of erythrocytes FIG. 14 shows the result of observing the migration speed of erythrocytes with a magnet arrangement using an iron piece. It can be seen that the red blood cells migrate in the 0.1 M manganese chloride aqueous solution in the same migration direction as the polysterene particles, that is, in the direction of magnetic buoyancy. Hemoglobin, the main component of red blood cells, is originally paramagnetic (volume susceptibility 1
0.08 × 10 ⁻⁶ ), but shows diamagnetism when oxygen is bonded. It is considered that the red blood cells used in the experiment contained both those bound to oxygen and those not bound to oxygen, but in any case, the magnetic susceptibility was 0.1M manganese chloride aqueous solution (volume magnetic susceptibility 10.54 x 10 ^It is thought that he swam due to magnetic buoyancy because it was much smaller than ^-6 ). FIG. 15 plots the migration speed of the red blood cells against B (dB / dx). B (dB /
Dx) is the result of an electrophoresis experiment on polystyrene particles (FIG. 13).
It is obtained from. Slope in this graph-2.7
2 × 10 ^{-8 (m} 2 s ^{over 1} T ^-2), the information about the red blood cells as can be seen from equation _{(5), 2 (χ p} -χ f) r 2 / 9μ
Since give mu _0, than this can be determined the volume magnetic susceptibility of erythrocytes. However, since red blood cells are not spherical but disk-shaped, their correction radius is calculated using the following correction formula.
We will estimate r.

(Equation 8)Where J is the characteristic length of the red blood cell migration direction (m) and V is the volume
(M³), A is the maximum cross-sectional area (m²)
It is. Red blood cell volume in blood 8 × 10^-17(M³)When
A / l = 5.5 × 10^-6Use (m) to correct red blood cells
The radius is 2.3 × 10^{− 6}(M), volume susceptibility is -17 × 10^-6
Becomes However, this value is the value of the volume susceptibility of red blood cells.
Is too big. So in a 0.1M manganese chloride aqueous solution
Assumes that the erythrocytes are slightly expanded, and adjusts the correction radius to 3
・ 0 × 10^-6(M) (volume is 1.3 × 10 ^-16(M³))When
Then, the volume susceptibility becomes −5.8 × 10^-6Is obtained. This value
Is the volume susceptibility of completely deoxygenated red blood cells-3.8 x
Ten^-6This is quite reasonable compared to. However, this
To accurately determine the volume susceptibility
Radius r²It is necessary to ask for.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic diagrams showing that a capillary is arranged through a minute gap between pole pieces, and FIG. 1C is a diagram showing Bd with respect to a capillary X-axis displacement.
It is a figure which shows B / dx.

FIG. 2 (a) shows a state in which permanent fine particles are attracted to a strong magnetic field, and FIG. 2 (b) shows a relationship between magnetic force acting on magnetic particles and magnetic buoyancy.

FIG. 3 schematically shows a device for measuring the migration speed of particles according to the present invention.

FIG. 4A is a magnetic field analysis software “SUPERMOME”.
(B) shows magnets and capillaries, X axis and Z
This shows the relationship with the axis.

FIG. 5A is a magnetic field analysis software “SUPERMOME”.
B "(dB / dx) / T of simulation by NT"
The measurement result of ² m ^-1 is shown, and (b) is (dB / dz)
/ Shows the results of measurement of ^T 2 ^{m -1.}

FIG. 6 shows a measurement example of the magnetophoretic behavior of a manganese chloride droplet in ethyl benzoate in a capillary.

FIG. 7 shows the results of measuring the velocity of a droplet in the X direction at 0 to 300 μm, and shows the position, particle size, and concentration dependence of the magnetophoretic velocity.

FIG. 8 shows the migration velocity (capillary axial component v _x ) of a 0.06 mol dm ⁻³ manganese chloride aqueous solution droplet, and the droplet radius r ^2.
FIG.

FIG. 9 shows the relationship between Δχ and manganese concentration in an experimental example.

FIG. 10 is a diagram in which the magnetophoretic kinetics when dry ethyl benzoate (a) and water-saturated ethyl benzoate (b) are used are plotted against manganese concentration.

FIG. 11 is a diagram plotting the magnetophoretic kinetics with respect to the manganese concentration in an experiment using ethyl benzoate saturated with water as a medium.

FIG. 12 is a graph showing the migration rate of polystyrene in 0.6 M manganese chloride in a strong magnetic field using an iron piece.

FIG. 13 is a graph showing the magnetic field intensity B (dB / dx) in the capillary determined from the migration speed.

FIG. 14 is a graph showing the migration speed of red blood cells in a magnetic field gradient generated by an iron piece.

FIG. 15 shows the migration speed of red blood cells and the magnetic field strength B (dB / d).
It is a graph which shows the relationship of x).

[Brief description of reference numerals]

DESCRIPTION OF SYMBOLS 1 ... A pair of magnet, 2 ... Microscope, 3 ... Irradiation light, 4 ... CCD camera, 5 ... Monitor device,
6 video tape recorder, 7 arithmetic unit (PC), 8 XY stage, MP magnetic pole piece,
C: Capillary

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F034 AA07 DA11 DA15 2F065 AA26 BB05 BB15 CC00 DD06 FF02 FF04 HH13 HH15 JJ03 JJ09 JJ26 PP12 PP24 QQ23 2G053 AB06 BA05 BA07 BA08 BC20 CB27 CB29

Claims (5)

[Claims] 1. Magnetophoretic velocity and particle diameter of magnetic fine particles suspended in a solvent in a cell installed in a magnetic field gradient are measured, and the measured magnetic migration velocity and particle diameter, viscosity and magnetization of a medium are measured. A method for measuring the magnetic susceptibility of individual fine particles, comprising determining the magnetic susceptibility of fine particles based on the magnetic susceptibility and the measured magnetic gradient. 2. Measuring the magnetophoretic velocity and particle diameter of magnetic fine particles of unknown magnetic susceptibility suspended in a solvent in a cell placed in a magnetic field gradient, while measuring a solvent in a cell placed in a magnetic field gradient. The magnetic field distribution is determined based on the measured values of the magnetophoretic velocity and the particle diameter of the magnetic particles having a known magnetic susceptibility suspended in a magnetic field. A method of measuring the magnetic susceptibility of individual magnetic fine particles, comprising determining the magnetic susceptibility of the fine particles based on the measured values of the magnetophoretic velocity and the particle diameter of the magnetic particles of unknown magnetic susceptibility. 3. The method according to claim 1, wherein when the magnetic fine particles are dissolved in a solvent, the magnetic susceptibility is corrected based on the solubility of the fine particles in the solvent. 4. A pair of magnets for forming a minute magnetic field, a cell installed in a minute magnetic field space formed between the pair of magnets, and filled with a solvent containing magnetic fine particles, A measuring device for measuring the magnetophoretic velocity of the magnetic fine particles in a solvent,
A magnetophoresis system comprising: a measuring device for measuring the radius of the fine particles; and an arithmetic unit for determining the magnetic susceptibility of the magnetic fine particles based on the measured magnetophoretic velocity and particle diameter of the fine particles, the viscosity and the magnetic susceptibility of the medium, and the measured magnetic gradient. Of the magnetic susceptibility of individual magnetic fine particles. 5. A measuring device for measuring a magnetophoretic velocity of magnetic fine particles in a solvent in a cell during application of a magnetic field, and a measuring device for measuring a radius of the fine particles, comprising: a microscope for observing the fine particles in the cell; CCD that converts the obtained image into electrical signals
5. The magnetic susceptibility measuring apparatus for individual magnetic fine particles of the magnetophoretic system according to claim 4, comprising a camera, a recorder for recording an electric signal converted by the CCD camera, and an analyzer for analyzing the recorded electric signal.