JP6943657B2 - Particle analyzer, particle analysis system, and particle analysis method - Google Patents

Description

The present invention relates to a particle analyzer that irradiates a sample containing a particle group in a dispersion medium with light and analyzes the characteristics of the particles or the particle group based on the scattered light.

For example, in order to control the quality of products manufactured using powder, the particle size distribution of the powder may be measured. Further, when the sample contains particles of, for example, 100 nanometers, and it is desired to measure the particle size distribution of such fine particles, it may be measured based on the dynamic light scattering method (DLS).

By the way, when the dynamic light scattering method is used, the intensity of the scattered light obtained by irradiating the sample with a laser beam is proportional to the sixth power of the particle diameter. Therefore, when the particle size distribution of the particle group contained in the sample is wide and particles of various particle sizes are mixed, the influence of particles larger than the particle size to be measured becomes dominant, and 100 nanometers. It becomes difficult to accurately measure the particle size distribution of order particles.

Therefore, when measuring a sample having a wide particle size distribution by the dynamic light scattering method, the sample is classified according to the size of the particle size by gel permeation chromatography (GPC) or the like, for example, the particle size is small. Measurements are made in order from the one. Then, by synthesizing the particle size distributions obtained from each of the plurality of classified samples to obtain the entire particle size distribution, the measurement accuracy can be improved even when the particle size distribution is wide.

However, the classifier by gel permeation chromatography is very expensive, and there is a problem that the device becomes large. Further, as shown in Patent Documents 1 and 2, even if the particles contained in the sample are classified and the particle size distribution is measured by a method other than gel permeation chromatography, for example, centrifugation, the particle size range is measured. It is necessary to prepare for dividing each of the classified samples so that batch measurement can be performed individually and storing them in cells separately, which does not solve the problem that the analysis is very troublesome.

Japanese Patent No. 5277906 Published Patent Gazette No. 60-500227

The present invention has been made in view of the above-mentioned problems, and as compared with the case of using gel permeation chromatography, for example, it is not necessary to prepare a plurality of samples and individually perform batch measurement. An object of the present invention is to provide a particle analyzer capable of analyzing the characteristics of a sample containing particles.

The particle analyzer according to the present invention irradiates a cell containing a sample in which a group of particles which is a dispersoid in a dispersion medium is classified according to a particle size along a predetermined direction and the cell with light. Light source, an irradiation point changing mechanism that changes the irradiation point of light in the cell along the predetermined direction, a scattered light detection mechanism that detects scattered light scattered by a group of particles, and a light irradiation point for each light irradiation point. An individual result storage unit that stores an actually measured amount of scattered light detected by the scattered light detection mechanism or a characteristic amount indicating the characteristics of a particle or a particle group calculated based on the actually measured amount of scattered light, and the individual result. It is characterized by including a synthesis result calculation unit that calculates the characteristic amount of the entire particle group contained in the sample based on a plurality of actually measured amounts stored in the storage unit or a plurality of characteristic amounts.

In such a case, since the irradiation point of the light to the cell is changed along the predetermined direction by the irradiation point changing mechanism, only the sample contained in one cell is contained in the cell. It is possible to analyze each part of the sample having a different particle size range. Therefore, there is no need to classify a sample in which particles of various particle sizes are mixed, prepare separate cells for each particle size range, and perform batch measurement.

Further, since the synthetic result calculation unit calculates the characteristic quantity of the entire particle group from the plurality of actually measured quantities obtained by the analysis in each particle diameter region or the plurality of characteristic quantities, the measurement is based on scattered light. Even when fine particles on the order of 100 nanometers are included, highly accurate particle analysis can be realized. That is, in particle analysis based on scattered light, even when the particle size range of the particle group contained in the sample is wide, the scattered light is accurately measured for each classified particle size range to obtain an accurate actual measurement amount. After that, each measured amount or each characteristic amount based on each measured amount is synthesized by the synthesis result calculation unit, so that the characteristic amount can be obtained accurately for the entire particle size region.

If the light source irradiates the cell with laser light and the characteristic quantity is the particle size distribution of the particle group calculated based on the dynamic light scattering method, the sample has a wide particle size distribution. However, accurate results can be obtained even for fine particles by a simple method, and by synthesizing each result, it is possible to obtain an accurate particle size distribution for the entire particle size region, and the above-mentioned effect of the present invention is more effective. It becomes remarkable.

The light source and the scattered light detection mechanism can be left fixed so that an error is less likely to occur in the setting of the optical system, and the irradiation point of light for the cell can be changed. The changing mechanism may be configured to move the cell along the predetermined direction to change the irradiation point of light in the cell. Here, the light irradiation point in the cell may be the spot range where the light is actually irradiated, or may be the intersection of the optical axis and the cell.

In order to maintain the density gradient of the dispersion medium in a stable manner and to classify the particle group from the lower part to the upper part from the particles having a large particle size to the particles having a small particle size only by centrifugation, the above. The predetermined direction may be the vertical direction, and the dispersion medium may be composed of a solute and a solvent, and a concentration gradient of the solute in the solvent may be formed along the vertical direction. In such a case, the particles in the sample are classified by the density gradient of the dispersion medium just by centrifuging, so it is possible to use an inexpensive centrifuge with a simple structure compared to the classifier. Therefore, it is possible to analyze a group of particles having a wide particle size range by a simpler method than before.

In order to enable consistent automation from sample preparation to sample analysis, a centrifuge that centrifuges a sample in which the particle group is not classified in a dispersion medium and a particle analyzer according to the present invention. A particle analysis system comprising the above, wherein the sample after being centrifuged by the centrifuge is analyzed by the particle analyzer.

Further, the particle analysis method according to the present invention includes an irradiation step of irradiating a sample in which a group of particles which are dispersoids in a dispersion medium is classified according to a particle size along a predetermined direction with light. An irradiation point changing step of changing the irradiation point of light in the sample along the predetermined direction, a scattered light detection step of detecting scattered light in which light is scattered by a group of particles, and the scattered light for each irradiation point of light. In the individual result storage step for storing the measured amount of scattered light detected in the detection step or the characteristic amount indicating the characteristics of the particles or the particle group calculated based on the measured amount of scattered light, and the individual result storage step. It is characterized by including a synthesis result calculation step of calculating the characteristic amount of the entire particle group contained in the sample based on a plurality of stored actual measurement amounts or a plurality of characteristic amounts.

With such a method, although it is a simple analysis method, it is possible to accurately obtain the characteristic amount of the entire particle size of particles having a wide particle size distribution by analysis based on scattered light.

Anything further provided with a sample generation step of producing a sample in which the dispersoid particle group is classified according to the particle size along the predetermined direction in the dispersion medium in which the density gradient is formed in the predetermined direction. For example, it is possible to obtain a sample classified into a state suitable for obtaining the characteristic amount of the entire particle size.

As a specific method for forming a classified state for each particle size region in one sample along the predetermined direction, the dispersion medium is composed of a solute and a solvent, and the sample generation step is performed. , A concentration gradient forming step of forming a concentration gradient of a solute in a solvent along the vertical direction in a state before the particle group which is the dispersoid is added to the dispersion medium, and the dispersoid with respect to the dispersion medium. There is a particle analysis method including a classification step of adding a particle group of the above and classifying by centrifugation.

In order to be able to enjoy the same effect as the particle analyzer according to the present invention only by updating the program in the existing apparatus, for example, the dispersoid particle group in the dispersion medium is particles along the predetermined direction. A cell that houses a sample in a state of being classified according to the diameter, a light source that irradiates the cell with light, an irradiation point changing mechanism that changes the irradiation point of light in the cell along the predetermined direction, and an irradiation point changing mechanism. A program used in a particle analyzer equipped with a scattered light detection mechanism that detects scattered light scattered by a group of particles, and the scattered light detected by the scattered light detection mechanism at each light irradiation point. An individual result storage unit that stores the measured amount or a characteristic amount indicating the characteristics of the particles or the particle group calculated based on the measured amount of scattered light, and a plurality of actually measured amounts stored in the individual result storage unit. Alternatively, a synthesis result calculation unit that calculates the characteristic amount of the entire particle group contained in the sample based on a plurality of characteristic amounts, and a program for a particle analyzer that exerts the function as a computer may be used.

The program for the particle analyzer may be electronically distributed or may be stored in a program storage medium such as a CD, DVD, HDD, or flash memory.

As described above, according to the particle analyzer according to the present invention, the irradiation point for the cell is changed, particle analysis is performed for each particle size region using a sample in one cell, and a characteristic amount is obtained in each particle size region. be able to. Then, since the characteristic amount of the entire particle area is calculated based on the characteristic amount obtained in each particle size range, it is possible to analyze the sample having a wide particle size distribution with high accuracy even if the analysis is performed by scattered light. can.

In addition, the samples are classified according to the particle size in one cell, and by changing the irradiation point of light by the irradiation point changing mechanism, analysis in each particle size range can be performed without cell replacement. can. Therefore, it is not necessary to prepare a cell for each classified sample as in the conventional case, and the time and effort required for preparation for analysis can be significantly reduced.

The schematic diagram which shows the particle size distribution measuring apparatus which concerns on 1st Embodiment of this invention, and the particle analysis system provided with this. The schematic diagram which shows the optical system of the particle size distribution measuring apparatus in 1st Embodiment. The functional block diagram which shows the control mechanism of the particle size distribution measuring apparatus in 1st Embodiment. The schematic diagram which shows the classification procedure of the sample in 1st Embodiment. The schematic diagram which shows the measurement process for each particle diameter region by changing the irradiation point of a laser beam in 1st Embodiment. The flowchart which shows the measurement procedure in 1st Embodiment. The functional block diagram which shows the control mechanism of the particle size distribution measuring apparatus which concerns on 2nd Embodiment of this invention.

The particle size distribution measuring device 100 and the particle analysis system 200 according to the first embodiment of the present invention will be described with reference to the respective figures. The particle size distribution measuring device 100 of the present embodiment is a kind of particle analyzer that measures the particle size as a characteristic value indicating the characteristics of the particle group contained in the sample. The particle size distribution measuring device 100 is used to measure the particle size distribution in a wide range including a particle size range on the order of 100 nanometers by a dynamic light scattering method (DLS).

In order to improve the measurement accuracy in the particle size distribution measuring device 100, in the present embodiment, a sample classified according to the particle size range is used in one cell C, and the particle size distribution is measured for each particle size range. Then, the overall particle size distribution is obtained by synthesizing the obtained results.

That is, as shown in FIG. 1, the particle analysis system 200 of the present embodiment has a centrifuge 101 for centrifuging the sample and a particle size distribution measuring device 100 for measuring the particle size distribution of the sample after centrifugation. And have.

In the centrifuge 101, the dispersion medium contained in the cell C and the dispersoid particle group were mixed by centrifugation and classified according to the particle size along the direction in which the centrifugal force acts. It is to make it into a state. The centrifuge 101 is configured so that the cell C, which is also used in the particle size distribution measuring device 100, can be installed as it is, and can be centrifuged by rotating the cell C at a high speed. That is, the cell C is set with respect to the centrifuge 101 so that, for example, the longitudinal direction of the cell C coincides with the radial direction on which the centrifugal force acts, and by centrifuging, the cell C is along the longitudinal direction of the cell C. The particle group is classified for each particle size range.

In the present embodiment, the particle size distribution measuring device 100 makes it possible to change the irradiation point of the laser beam on the cell C so that the measurement can be performed at a plurality of points on one cell C. More specifically, the particle size distribution measuring device 100 holds the laser light source LS from which the laser light is emitted, the cell C, and the irradiation point changing mechanism 1 configured to be able to change the position in the vertical direction thereof, and the above. It was composed of a scattered light detection mechanism D composed of a plurality of detectors D1, D2, and D3 arranged around the cell C, and a computer that calculates a particle size distribution based on a part or all of the output of each detector. It is equipped with a control calculation mechanism COM. Here, the detector D1 is a photodiode, and detects the intensity of the transmitted light transmitted through the cell C. The detectors D2 and D3 are, for example, photomultiplier tubes, and detect the intensity of scattered light from the cell C. Which of the scattered light intensities of the detectors D2 and D3 is used is set according to the intensity of the transmitted light detected by the detector D1.

As shown in FIG. 2A, the laser light source LS and the scattered light detection mechanism D are arranged, for example, in the same horizontal plane. The laser light emitted from the laser light source LS enters the cell C, and the particles generate scattered light. Further, a part of the cell C is arranged in this horizontal plane and is irradiated with the laser beam. As shown in FIG. 2B, the irradiation point changing mechanism 1 moves the cell C up and down only in the vertical direction without changing the position in the horizontal plane to change the irradiation point of the laser beam.

The irradiation point changing mechanism 1 is a support mechanism that vertically supports a part of the cell C so that the optical path of the laser beam intersects, and by adjusting the rotation amount of the stepping motor included in the support mechanism, the cell The position of the irradiation point of the laser beam in C can be changed as appropriate.

The control calculation mechanism COM is configured by using a so-called computer equipped with a CPU, a memory, an A / D / D / A converter, an input / output means, a display, etc., and a program for a particle analyzer stored in the memory is provided. When executed and various devices collaborate, as shown in FIG. 4, at least the functions of the cell position control unit 2, the particle size distribution calculation unit 3, the individual result storage unit 4, and the synthesis result calculation unit 5 are exhibited. ..

The cell position control unit 2 controls the stepping motor of the irradiation point changing mechanism 1 so that the laser beam is irradiated to the position to be measured in the sample in the cell C. In the present embodiment, for example, the amount of movement of the cell C in the vertical direction is controlled so that the laser beam is irradiated to three measurement positions in the cell C. For example, the movement amount is controlled in units of 1 μm at the minimum. The cell position control unit 2 does not always move the cell position at equal intervals of 1 μm, which is the minimum movement unit, but forms a region where the measurement is densely performed and a region where the measurement is roughly performed in the cell C. As described above, the movement amount of the cell C is appropriately changed. More specifically, the cell position control unit 2 moves the particles in the cell C in a density of 1 μm, which is the minimum movement unit, for example, in the center portion, and the particles are scattered in the cell C. The area included in the upper end and the lower end where the particle size is small is moved in units of 10 μm. Further, the position command value from the cell position control unit 2 to the stepping motor or the cell position information based on the signal output from the encoder provided in the stepping motor is transmitted to the individual result storage unit 4 for each measurement. Will be done. The cell position may be controlled by an open loop control or a feedback control by a closed loop based on the rotation amount of the motor.

The particle size distribution calculation unit 3 uses the dynamic light scattering method (DLS) to formulate the Stokes-Einstein equation based on the fluctuation of the intensity of the scattered light, which is the measured amount of the scattered light detected by the scattered light detection mechanism D. It is a characteristic amount calculation unit that calculates a particle size distribution, which is one of the characteristic amounts indicating the characteristics of the particle group based on the above. In the present embodiment, the cell position control unit 2 calculates the particle size distribution based on the intensity of the scattered light obtained at that time each time the irradiation point of the laser light on the cell C is changed. From the scattered light detection mechanism D, the fluctuation of the scattered light intensity obtained by the detectors D1, D2, and D3 is output in the form of an autocorrelation function of the scattered light intensity as an actual measurement amount by calculation by an electric circuit. There is. The particle size distribution calculation unit 3 sequentially calculates the particle size distribution of the particle group included in the point where the laser beam is currently irradiated as a characteristic quantity from the autocorrelation function which is an actually measured quantity.

The individual result storage unit 4 stores the particle size distribution, which is a characteristic quantity calculated for each irradiation point of the laser beam. The particle size distribution stored in the individual result storage unit 4 individually stores the proportion of the particle size in each particle size range. Further, the data regarding the cell position transmitted from the cell position control unit 2 for each laser beam irradiation point is stored in association with the particle size distribution for each laser beam irradiation point.

The synthesis result calculation unit 5 is based on the plurality of particle size distributions stored in the individual result storage unit 4 and the cell position data in which each particle size distribution is measured, and the particle size distribution of the entire particle group included in the sample. Is calculated. In the first embodiment, the particle size distribution is not measured by sampling at equal intervals, but the measurement is performed so that the density is generated at the intervals of the measurement points. Therefore, the particle size distribution stored in the individual result storage unit 4 is performed. If the simple arithmetic average is calculated by simply adding and dividing by the number of measurement points, the particle size distribution in the region where the measurement points are dense is overestimated, and the particle size distribution in the entire particle size region cannot be obtained correctly. Therefore, the synthesis result calculation unit 5 changes the weighting of each particle size distribution based on the cell position data stored in the individual result storage unit 4 in association with the particle size distribution, and the particles in the entire particle size range. I try to calculate the diameter distribution. Specifically, regarding the particle size distribution obtained in the dense region where the cell C moves at 1 μm intervals after weighting by the scattered light intensity, the particle size distribution is obtained in the coarse region where the cell C moves at 10 μm intervals. The synthesis result calculation unit 5 is configured so that the weighting of the 1/10 position of the obtained particle size distribution is performed and the weight of each particle size is constantly evaluated over the entire particle size range.

The operation related to the measurement of the particle size distribution by the particle analysis system 200 of the present embodiment configured as described above will be described with reference to the schematic views of FIGS. 5 and 6 and the flowchart of FIG. 7.

First, a procedure for producing a sample in cell C will be described.

First, pure water W is further added to the sugar water S in the cell C (step S1). If left in this state for a predetermined time, a dispersion medium having a density gradient formed in the vertical direction is formed (step S2). Here, the dispersion medium is a solution containing water as a solvent and sucrose as a solute, and as shown in FIG. 5A, the concentration gradient in the vertical direction due to the action of gravity from the initial state of being divided into two layers. Is formed. The solute may be any substance that is not detected by the dynamic light scattering method and is soluble in a solvent.

The powder to be measured is placed on the liquid surface of the dispersion medium on which the density gradient is formed (step S3), and the cell C is placed in the centrifuge 101 to perform centrifugation (step S4). ). Then, as shown in FIG. 5B, the particles are classified in the cell C according to the density gradient of the dispersion medium, and separated layers are formed for each particle size region (step S5). As shown in FIG. 5B, for example, particles having a larger particle size gather on the lower end side where the density of the dispersion medium is higher, and particles having a smaller particle size gather on the liquid surface side where the density of the dispersion medium is lower. Then, a layer of a particle group is formed in each particle diameter region according to the height in the vertical direction in the cell C. As can be seen from FIG. 5B, the classification in the present specification is not only a state in which the particles are continuously arranged according to the particle size in the dispersion medium, but also a predetermined particle size region. It is a concept that includes states.

When a sample in which the particle size region is classified and separated along the vertical direction in the cell C is obtained in this way, the cell C is attached to the irradiation point changing mechanism 1 of the particle size distribution measuring device 100 (step). S6). The irradiation point changing mechanism 1 sets the height of the cell C to the initial position (step S7), measures the particle size distribution at the set position, and stores the result in the individual result storage unit 4. (Step S8).

For example, the cell position control unit 2 determines whether or not all the predetermined measurements have been performed (step S9), and if all the measurements have not been completed, the irradiation point changing mechanism 1 causes the cell C to be vertical. The height in the direction is changed (step S10), and steps S8 to S10 are repeated until all the measurements are completed. That is, as shown in FIG. 6, the irradiation point of the laser beam is changed from the liquid surface side to the bottom surface side of the dispersion medium, and each time the irradiation point is changed, the particle size distribution of the particle group contained in the layer is changed. Is sequentially measured and stored in the individual result storage unit 4. The cell position control unit 2 determines whether the cell C is moved in the smallest unit or in a larger unit depending on the current position with respect to the movement interval of the cell C for changing the irradiation point of the laser beam. ..

When the measurement of the particle size distribution in each layer of the dispersion medium contained in one cell C is completed, the synthesis result calculation unit 5 receives the particle size distribution of each particle size range stored in the individual result storage unit 4. Based on the result and the movement interval calculated from the position of cell C when each particle size distribution is measured, the particle size distribution of the entire particle size range included in the sample is calculated and output to the display ( Step S11).

As described above, according to the particle analysis system 200 of the first embodiment, the powder to be measured is added to the dispersion medium having a density gradient in the vertical direction in the cell C, and the dispersion medium is centrifuged by a simple method of centrifugation. It is possible to obtain a sample in which the particle group is classified according to the particle size. Therefore, it is not necessary to prepare a large and expensive device such as a classifier using gel permeation chromatography.

Further, the particle size distribution measuring device 100 irradiates the sample classified according to the particle size along the vertical direction in one cell C by moving the cell C in the vertical direction to irradiate the laser beam. The point can be changed and the particle size distribution can be measured for each particle region. Therefore, by limiting the particle size range to maintain high measurement accuracy of the particle size distribution and synthesizing the obtained plurality of measurement results, the particle size distribution of the entire particle size can be obtained with high accuracy. Therefore, when a sample containing particles having a wide particle size range is measured by a dynamic light scattering method, the measurement accuracy cannot be maintained for a minute region on the order of 100 nanometers, for example. If this is the case, good measurement accuracy can be achieved over the entire area.

In addition, it is not necessary to prepare individual cells C for measuring the particle size distribution for each of a plurality of particle size regions, and the time and effort required for preparation for measurement can be significantly reduced as compared with the conventional case.

Next, the particle analyzer 100 and the particle analysis system 200 according to the second embodiment of the present invention will be described with reference to FIG. 7.

In the second embodiment, as shown in FIG. 7, the particle size distribution calculation unit 3 which is a characteristic amount calculation unit is omitted, and the individual result storage unit 4 actually measures the scattered light obtained by the scattered light detection mechanism D. The amount of scattered light intensity data is directly stored. Further, the synthesis result calculation unit 5 calculates the particle size distribution based on the measured amount of scattered light at each irradiation point stored in the individual result storage unit 4, and then synthesizes each particle size distribution to obtain particles. It is configured to calculate the particle size distribution over the entire diameter range.

Even in such a case, the measurement is based on the dynamic light scattering method as in the first embodiment, and the entire particle size distribution can be obtained with high accuracy even when the particle size range is wide.

Other embodiments will be described.

In the above embodiment, the particle size distribution is calculated as the characteristic quantity of the particles or the particle group, but the characteristic quantity is an amount indicating the characteristics of the particles or the particle group that can be measured based on the scattered light. good. For example, various characteristics such as zeta potential, molecular weight of particles, viscosity of sample, and characteristics of protein may be calculated. Further, the characteristic quantity may be calculated based on the scattered light, and for example, the characteristic quantity such as the particle size distribution may be calculated based on the static light scattering method. Further, the measured amount obtained from the scattered light detection mechanism may not be the autocorrelation function required in the dynamic light scattering method, but may be the time-series data itself of the intensity of the scattered light. In this case, the individual result storage unit may store the time-series data of the intensity of the scattered light obtained at each measurement point. Further, if the static light scattering method is used, the scattered light intensity distribution may be output from the scattered light detection mechanism as an actually measured amount and stored in the individual result storage unit. In addition, the synthesis result calculation unit calculates an autocorrelation function from each time-series data of the intensity of scattered light, then calculates a particle size distribution as a characteristic quantity, synthesizes the particle size distribution, and distributes the particle size in the entire particle size range. May be configured to obtain.

The interval of changing the irradiation position of light with respect to the cell by the irradiation point changing mechanism may be a constant interval. In such a case, the synthesis result calculation unit may be configured to weight a plurality of characteristic quantities by the scattered light intensity and then calculate the characteristic quantity of the entire particle size region by a simple arithmetic mean or the like. Further, the synthesis result calculation unit may perform curve fitting so as to connect a plurality of particle size distributions to obtain the particle size distribution of the entire particle size range.

The method for producing a dispersion medium having a density gradient is not limited to that shown in the above embodiment. For example, a density gradient may be formed by accommodating sugar waters having different concentrations in a layer in the cell. Here, the density gradient may change not only continuously along a predetermined direction but also discontinuously at the boundary. Even in such a case, it is possible to classify and separate according to the particle size by centrifugation as in the above embodiment. Further, the density or concentration does not have to change monotonically along a predetermined direction. Further, the cells may be classified according to the particle size by, for example, a natural sedimentation method without using centrifugation. In addition, the dispersion medium is not limited to sugar water, and the solvent and solute constituting the dispersion medium may be appropriately selected. That is, as the solvent and solute, those that do not easily affect the measurement of the scattered light of the dispersoid may be selected. In addition, by sequentially accommodating the particles classified by a classifier such as GPC in the cell, a state in which the particles are classified according to the particle size along a predetermined direction may be realized.

In the above embodiment, the irradiation point of the laser beam to the cell can be changed by moving the cell in the vertical direction, but the position of the cell is fixed and the laser light source and the scattered light detection mechanism are moved. The irradiation point changing mechanism may be configured so that the irradiation point of the laser beam in the cell is changed. Further, the laser light source may be an LED or a halogen light source that emits a beam having low directivity depending on the measurement principle.

Further, the predetermined direction in which the density gradient is formed is not limited to the vertical direction, and may be a horizontal direction, an oblique direction, or the like. The irradiation point of the laser beam may be changed along the direction of the density gradient.

When the irradiation point of light to the cell is switched and the scattered light is detected for each particle size range, the scattered light detection mechanism maintains a predetermined S / N ratio regardless of the particle size range, and the output is saturated. In order to prevent this, a filter mechanism that can change the degree of attenuation is provided on the optical path between the light source and the cell so that the optimum filter is selected for each measurement. good. For example, when the irradiation point is changed in order from a region having a large particle size region to a region having a small particle size region and the intensity of scattered light is detected, the degree of dimming of the filter mechanism may be gradually reduced. After doing so, the scattered light intensity measured by the scattered light detection mechanism can be returned to the actual scattered light intensity by dividing it by the degree of attenuation with the filter mechanism at that time, and for example, the particle size distribution can be calculated. can.

The particle group to be measured by the particle analyzer according to the present invention may contain a single type of particles or may contain a plurality of different types of particles. .. When different types of particles are contained in the sample and each has almost the same density, characteristic quantities such as particle size distribution in a state where different types of particles are mixed are determined for each particle size range. By measuring with high accuracy and synthesizing each characteristic quantity, it is possible to obtain an accurate characteristic quantity over the entire particle diameter range in which a plurality of types of particles are mixed. In addition, if the sample contains different types of particles with different densities, for example, each particle type can be separated and classified in the cell, multipoint measurement is performed for each particle type, and the measurement is performed. Based on the result, the synthesis result calculation unit may be configured to calculate the characteristic amount such as the particle size distribution of the entire particle size range for each type of particle.

In addition, various embodiments may be modified or combined as long as they do not contradict the gist of the present invention.

200 ... Particle analysis system 100 ... Particle size distribution measuring device (particle analyzer)
101 ・ ・ ・ Centrifugator LS ・ ・ ・ Laser light source D ・ ・ ・ Scattered light detection mechanism C ・ ・ ・ Cell 1 ・ ・ ・ Irradiation point change mechanism 2 ・ ・ ・ Cell position control unit 3 ・ ・ ・ Particle size distribution calculation Part (characteristic quantity calculation part)
4 ・ ・ ・ Individual result storage unit 5 ・ ・ ・ Synthesis result calculation unit

Claims (6)

A cell containing a sample in which particles that are dispersoids in the dispersion medium are classified according to the particle size along a predetermined direction, and a cell that accommodates the sample.
A light source that irradiates the cell with light,
An irradiation point changing mechanism that changes the irradiation point of light in the cell along the predetermined direction,
A scattered light detection mechanism that detects scattered light scattered by a group of particles,
Individual result for storing the measured amount of scattered light detected by the scattered light detection mechanism or the characteristic amount indicating the characteristics of the particles or the particle group calculated based on the measured amount of scattered light for each light irradiation point. Memory and
A synthesis result calculation unit for calculating the characteristic amount of the entire particle group included in the sample based on a plurality of actually measured quantities stored in the individual result storage unit or a plurality of characteristic quantities is provided .
The predetermined direction is the vertical direction,
A particle analyzer in which the dispersion medium is composed of a solute and a solvent, and a concentration gradient of the solute in the solvent is formed along the vertical direction. The light source irradiates the cell with laser light.
The particle analyzer according to claim 1, wherein the characteristic quantity is a particle size distribution of a particle group calculated based on a dynamic light scattering method. The particle analyzer according to claim 1, wherein the irradiation point changing mechanism is configured to move the cell along the predetermined direction to change the irradiation point of light in the cell. A centrifuge that centrifuges a sample in which the particle group is not classified in the dispersion medium,
A particle analysis system comprising the particle analyzer according to any one of claims 1 to 3.
A particle analysis system configured such that a sample after being centrifuged by the centrifuge is analyzed by the particle analyzer. A sample generation step of producing a sample in which particles that are dispersoids are classified according to the particle size along the predetermined direction in a dispersion medium having a density gradient formed in a predetermined direction.
An irradiation step of irradiating light to the sample in the state in which the particles are dispersed substance is classified according to the particle diameter along the predetermined direction in the dispersion medium,
An irradiation point changing step of changing the irradiation point of light in the sample along the predetermined direction, and
A scattered light detection step that detects scattered light scattered by a group of particles,
Individual result for storing the measured amount of scattered light detected in the scattered light detection step or the characteristic amount indicating the characteristics of the particles or the particle group calculated based on the measured amount of scattered light for each light irradiation point. Memory steps and
A synthesis result calculation step for calculating the characteristic amount of the entire particle group contained in the sample based on a plurality of actually measured quantities stored in the individual result storage step or a plurality of characteristic quantities is provided.
The dispersion medium is composed of a solute and a solvent, and is composed of a solute and a solvent.
The sample generation step
A particle analysis method comprising a concentration gradient forming step of forming a concentration gradient of a solute in a solvent along a vertical direction in a state before the particles group which is the dispersoid is added to the dispersion medium. The sample generation step
The particle analysis method according to claim 5, further comprising a classification step of adding the dispersoid particle group to the dispersion medium and classifying the particles by centrifugation .

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