Sample measuring device and sample measuring method

Abstract

The sample measuring device comprises: a sample container for storing a sample solution; a light source for irradiating the sample container with irradiation light from a first direction; a photographing unit for photographing an image of the sample solution based on light scattered in the sample solution from a second direction intersecting the first direction; and a computing unit for computing the absorbance or concentration of the sample solution based on the image. The computing unit computes the attenuation degree of the light amount of the image in a fixed optical path length along the first direction based on the image, and computes the absorbance or concentration of the sample solution according to the attenuation degree.

Description

Technical Field

[0001] The present invention relates to a sample measuring device and a sample measuring method for measuring the absorbance or concentration of a sample. Background Art

[0002] One method for measuring the concentration of a component in a sample (sample solution) is absorptiometry, which is a method of irradiating a sample with light, measuring the amount of transmitted light, and quantifying the concentration from the attenuation of the light (absorbance) using the Lambert-Beer law.

[0003] The Lambert-Beer law refers to the law that the absorbance of a solution is proportional to the concentration of the solution and the thickness of the solution (the optical path length of the unit added to the solution). The law that the absorbance is proportional to the optical path length when the concentration is fixed is called Lambert's law, and the law that the absorbance is proportional to the concentration of the solution when the optical path length is fixed is called Beer's law. In the determination of the concentration of components in a sample using absorptiometry, it is required to be able to measure a wider concentration range (dynamic range) with a simpler structure. For example, as a sample measurement device that can make the unit optical path length variable and expand the dynamic range, for example, patent documents 1 to 3 are known.

[0004] However, in the measurement of such an absorptiometry method for measuring the amount of transmitted light, there is a problem that the deviation of the amount of light from the light source is directly reflected in the deviation of the measurement result of the concentration. The deviation of the amount of light is caused by, for example, a change in the amount of light emitted by the light source due to temperature changes. For example, when an LED light source is used, the amount of light emitted is easily changed by temperature. As described above, when a simple structure such as an LED or a camera is used, there is a problem that the deviation of the amount of light is large, the concentration cannot be accurately measured during sample measurement, and the dynamic range is narrowed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-340804

[0008] Patent Document 2: Japanese Patent Application Publication No. 2006-194775

[0009] Patent Document 3: Japanese Patent No. 4220879 Summary of the invention

[0010] Problems to be solved by the invention

[0011] The present invention has been made in view of the above problems, and an object of the present invention is to provide a sample measuring device and method that can accurately measure the absorbance or concentration of a sample and obtain a high dynamic range even when the light intensity of a light source is unstable.

[0012] Means for solving problems

[0013] The sample measuring device of the present invention comprises: a sample container that stores a sample solution; a light source that irradiates the sample container with irradiation light from a first direction; a photographing unit that photographs an image of the sample solution based on light scattered in the sample solution from a second direction intersecting the first direction; and a computing unit that computes the absorbance or concentration of the sample solution based on the image. The computing unit computes the attenuation degree of the light amount of the image in a fixed optical path length along the first direction based on the image, and computes the absorbance or concentration of the sample solution according to the attenuation degree.

[0014] In addition, the sample measurement method of the present invention is characterized in that a sample solution is stored in a sample container, light is irradiated to the sample container from a first direction, an image of the sample solution based on light scattered in the sample solution is captured from a second direction intersecting the first direction, the attenuation degree of the amount of light in the image in a fixed optical path length along the first direction is calculated based on the image, and the absorbance or concentration of the sample solution is calculated based on the attenuation degree.

[0015] Effects of the Invention

[0016] According to the present invention, when the irradiation light emitted from the light source is irradiated from the first direction of the sample container, the irradiation light is scattered in the sample solution. Based on the scattered light, the image of the sample solution is captured by the imaging unit from the second direction intersecting the first direction. The calculation unit calculates the absorbance or concentration of the sample solution based on the image. At this time, the calculation unit calculates the attenuation degree of the light amount of the image along the first direction, and calculates the concentration of the sample solution according to the attenuation degree. In the present invention, the light irradiated from the first direction and scattered at multiple different positions in the sample solution is captured as an image in the imaging unit from the second direction, and the absorbance or concentration of the sample solution is calculated according to the attenuation degree. The attenuation degree does not change significantly in a fixed optical path length even if there is a change in the light amount of the irradiation light irradiated from the light source. In the sample solution in the sample container, the irradiation light is scattered at multiple positions in the first direction, and the optical path lengths of these multiple positions are different from each other. Therefore, it is possible to perform measurements with different optical path lengths without adding a complex structure. Therefore, according to the present invention, it is possible to provide a sample measurement device and method that can accurately measure the concentration even when the light amount of the light source is unstable and can obtain a high dynamic range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram for explaining the schematic configuration of the sample measurement device according to the first embodiment.

[0018] Figure 2This is a schematic diagram for explaining the operation of the sample measurement device according to the first embodiment.

[0019] Figure 3 This is a schematic diagram illustrating the schematic configuration of a sample measurement device according to the second embodiment.

[0020] Figure 4 This is a flowchart for explaining the operation of the sample measuring device according to the second embodiment.

[0021] Figure 5 This is a graph showing the relationship between the distance L and the light intensity value (normalized) obtained by imaging the calibration solutions Sc1 to Sc5 with the camera 14 .

[0022] Figure 6 This is an example of a calibration curve obtained based on the measurement results of calibration solutions Sc1 to Sc5. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements are sometimes shown with the same number. In addition, the accompanying drawings show embodiments and installation examples based on the principles of the present disclosure, but they are drawings for understanding the present disclosure and are by no means used to interpret the present disclosure in a limiting manner. The description in this specification is merely a typical illustration and does not limit the claims or application examples of the present disclosure in any sense.

[0024] In this embodiment, the present disclosure is fully and in detail described for those skilled in the art, but other installations and methods are also possible, and it is necessary to understand that the structure and construction can be changed and various elements can be replaced without departing from the scope and spirit of the technical idea of ​​the present disclosure. Therefore, the following description is not limited to this for interpretation.

[0025] [First embodiment]

[0026] Reference Figure 1-2 , a sample measuring device according to a first embodiment is described. As an example, the sample measuring device 1 is configured to include a sample container 11, a light source 12, a focusing lens 13, a camera 14 (photographing unit), an A / D converter 15, a calculation control unit 16 (calculation unit), and a display 18, and is configured to be able to measure the absorbance or concentration of a sample solution Sm in the sample container 11.

[0027] The sample container 11 is, for example, a rectangular container at least partially made of a transparent material and capable of containing a sample solution Sm (sample) to be measured. The sample container 11 here includes a first surface S1 that is at least partially transparent and a second surface S2 that intersects the first surface S1 and is at least partially transparent. The shape of the sample container 11 is not limited to a rectangular shape, and containers of various shapes can be used as long as the measurement method described below can be performed. Figure 1 In the figure, the direction approximately perpendicular to the first surface S1 is set as the X direction (first direction), and the direction approximately perpendicular to the second surface S2 is set as the Y direction (second direction), but the first surface S1 and the second surface S2 do not need to be approximately perpendicular to each other, as long as they are in a positional relationship capable of observing scattered light as described later.

[0028] A light source 12 is arranged on the first surface S1 via a focusing lens 13. As an example, the light source 12 is an LED (Light Emitting Diode), for example, a monochromatic LED with a light emission wavelength of 660nm can be preferably used. However, the light emission wavelength is not limited to this. In addition, the light emission wavelength does not need to be a single wavelength, and a light source that emits light in multiple wavelength bands can also be used. The irradiation light L1 emitted from the light source 12 is focused by the focusing lens 13 and irradiated to the sample solution Sm via the first surface S1. Particles are mixed in the sample solution Sm. As an example of particles, latex particles can be cited, but it is not limited to this. The irradiation light L1 incident on the sample solution Sm along the X direction from the first surface S1 is scattered by the particles, and a part of it is scattered in the Y direction.

[0029] The camera 14 is opposite to the second surface S2, and captures the sample container 11 and the sample solution Sm from the Y direction substantially perpendicular to the second surface S2 to obtain an image signal. Figure 1 The sample container 11 is independently arranged in the sample container 11, but the sample container 11 and the camera 14 may also be an integrated structure. The image signal obtained by the camera 14 is converted into image data as a digital signal in the A / D converter 15, and then input to the calculation control unit 16. The calculation control unit 16 calculates the attenuation degree (absorbance) of the light amount between at least two points in the image (between known optical path lengths) in the digital image data, and calculates the concentration (particle concentration) of the particles of the sample solution Sm based on the calculation result. The calculated concentration is displayed on the display 18.

[0030] The calculation control unit 16 can be composed of a general-purpose computer, for example, and generates data on the concentration of the sample solution Sm by performing prescribed calculation processing on the image data input as digital data from the camera 14. When a general-purpose computer is used, the program is executed by a processor (such as a CPU, a GPU) contained inside, and the processing determined by the program is performed simultaneously using storage resources (such as a memory), an interface device (such as a communication port), etc., thereby being able to perform necessary calculation processing. The processor may also include a dedicated circuit for performing specific processing. Here, the dedicated circuit is, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a CPLD (Complex Programmable Logic Device), etc.

[0031] The program may also be installed to a computer from a program source. The program source may also be, for example, a program distribution server or a computer-readable storage medium. In the case where the program source is a program publishing server, the program publishing server may include a processor and a storage resource for storing the program of the publishing object, and the processor of the program publishing server publishes the program of the publishing object to other computers. In addition, in the embodiment, more than two programs may be implemented as one program, or one program may be implemented as more than two programs.

[0032] Next, refer to Figure 2 Next, a method for calculating the concentration of the sample solution Sm in the first embodiment will be described.

[0033] If the irradiation light L1 is irradiated from the first surface S1, the irradiation light L1 Figure 2 The sample solution Sm irradiated by the irradiation light L1 is photographed from the Y direction by the camera 14 to obtain the image data. The image data is stored in a storage unit (not shown) in the calculation control unit 16.

[0034] Figure 2 The graph below shows an example of the relationship between the distance L from the first surface S1 at the position of the sample solution Sm irradiated with the irradiation light L1 in the image data and the light intensity value (normalized) at the position.

[0035] Due to scattered light, the light intensity value is maximum near a position P1 slightly away from the first surface S1 (distance L from the first surface S1 = L1), and then decreases as it is further away from the first surface S1. For example, when there are measurement points P1, P2, P3, and P4 in the order of being away from the first surface S1, when the light intensity of an image of each measurement point P1 to P4 is measured, the light intensity of the image decreases as it is further away from the first surface S1 due to scattering of particles, etc.

[0036] The greater the concentration of the sample solution Sm, the greater the attenuation degree (slope) in the graph. Therefore, in the calculation control unit 16, any two points of known optical path length, such as the measurement point P2 (first measurement point: distance L = L2) and the measurement point P3 (second measurement point: distance L = L3 ≠ L2), are determined, and the light intensity values ​​Q2 and Q3 are measured at the two determined measurement points P2 and P3. Then, the attenuation degree of the light intensity value between the two points (hereinafter referred to as attenuation Da) = (Q3-Q2) / (L3-L2) is calculated. Although the illustration is omitted, the calculation control unit 16 has a lookup table indicating the relationship between the attenuation Da and the concentration of the sample solution Sm, and the concentration of the sample solution Sm is determined by referring to the lookup table. In addition, the positions of the measurement points P2 and P3 of the measurement object can be appropriately changed. When the positions of the measurement points P2 and P3 are changed, the lookup table is also changed according to their positions.

[0037] In addition, measurement may be performed according to the measurement values ​​at other multiple measurement points instead of using the measurement values ​​at the measurement points P2 and P3. For example, when the concentration of the sample solution Sm to be measured is very high, the light intensity value Q3 at the measurement point P3 far from the first surface S1 becomes a very small value, and it may be difficult to measure. In this case, measurement can be performed at the measurement points P1 and P2, which are points closer to the first surface S1, and the concentration can be calculated based on the measurement results, instead of the measurement at the measurement points P2 and P3.

[0038] According to the structure and measurement method of the first embodiment, even if the light amount of the irradiation light L1 from the light source 12 changes due to some reason (temperature change, power supply change, etc.), the concentration of the sample solution Sm can be accurately measured, and the measurement can be performed with a high dynamic range. In the first embodiment, the concentration of the sample solution Sm is measured based on the attenuation amount Da of the light amount of the image between at least two points in the sample solution Sm.

[0039] If the amount of light of the irradiation light L1 changes, the amount of light of the image at each measurement point changes accordingly. However, the ratio of the change in the amount of light at each measurement point relative to the change in the amount of light of a certain irradiation light L1 is roughly the same between multiple measurement points. Therefore, the attenuation amount Da is independent of the change in the amount of light of the irradiation light L1 and does not change significantly. Therefore, according to this first embodiment, even if the amount of light of the irradiation light L1 changes, the concentration of the sample solution Sm can be accurately measured. In addition, the positions of the measurement points P1 to P4 can be easily changed in the calculation control unit 16 without the need for a complex additional structure, so it is also possible to perform measurements with appropriately changed optical path lengths. Therefore, measurements can be performed with a high dynamic range.

[0040] In addition, in the first embodiment described above, the case where the concentration of the particles in the sample solution Sm (sample) is measured by utilizing the scattering of light in the particles is mainly described. The concentration of the particles in the sample solution Sm may be set constant, and the concentration of the light absorbing substance in the sample solution Sm may be measured instead of measuring the concentration of the particles in the sample solution Sm. In this case, among the light intensity values ​​in the image data measured by the camera 14 and the operation control unit 16, the component based on the scattered light is constant, and on the other hand, the more light absorbing substances there are, the greater the light intensity value.

[0041] [Second embodiment]

[0042] Next, refer to Figure 3 to Figure 6 , a sample measuring device according to a second embodiment is described. Figure 3 2 is a schematic diagram illustrating the overall structure of a sample measuring device according to a second embodiment. Figure 3 Regarding the first embodiment ( Figure 1 ) the same structural elements, in Figure 3 The same reference numerals are used in the figures, and repeated descriptions are omitted below. The second embodiment is different from the first embodiment in that a calibration data storage unit 19 is provided to store calibration data, and the concentration of the sample solution Da to be measured can be measured based on the calibration data.

[0043] The calibration data storage unit 19 is a storage unit for storing calibration data obtained by measuring calibration solutions with known concentrations. The calibration data is obtained by measuring a plurality of calibration solutions with known concentrations in advance, and represents the relationship between the attenuation amount Da and the absorbance Ab. When the attenuation amount Da of the sample solution Sm to be measured is obtained by the same method as in the first embodiment, the absorbance or concentration of the sample solution Sm can be accurately measured by referring to the calibration data. By referring to the calibration data obtained based on the measurement results of the calibration solution with known concentrations and performing the measurement, a more reliable measurement result can be obtained.

[0044] Next, refer to Figures 4 to 6 The execution procedure of the concentration measurement method in the second embodiment will be described. Figure 4 is a flow chart showing the execution steps of the measurement method, Figure 5 as well as Figure 6 The method of generating correction data in the second embodiment is explained with reference to the diagram.

[0045] In this method, before measuring the sample solution Sm of the measurement object, the calibration solutions Sc (here, five calibration solutions Sc1 to Sc5) are sequentially injected into the sample solution 11, and the same method as that for measuring the sample solution Sm in the first embodiment is used ( Figure 2 That is, the sample container 11 into which the calibration solutions Sc1 to Sc5 are injected is irradiated with the irradiation light L1 from the X direction, and an image based on the scattered light is captured from the Y direction by the camera 14, and the resulting image data is stored in the calibration data storage unit 19 (step S11).

[0046] Next, the calculation control unit 16 analyzes the image data of the calibration solutions Sc1 to Sc5 obtained in step S11, calculates the light intensity value at each measurement point (after normalization), and generates a calibration curve (step S12).

[0047] Figure 5 This is a graph showing an example of the relationship between the distance L of each measurement point from the first surface S1 and the light intensity value (normalized) at each measurement point in the image data of the calibration solutions Sc1 to Sc5. The calibration solutions Sc1 to Sc5 have different concentrations and absorbances Ab. The greater the concentration and absorbance Ab, the greater the degree of decrease in the light intensity value at the same distance. Figure 5 In the example of , the concentration of the calibration solution Sc1 is the smallest, and the concentrations of the calibration solutions Sc2, Sc3, Sc4, and Sc5 are increased in the following order. Therefore, the slope (attenuation) of the obtained graph also increases in sequence. As an example, the calculation control unit 16 measures the attenuation Da, which is the degree of decrease in the light intensity value (normalized) between the measurement point P2 (distance L2) and the measurement point P3 (distance L3), and generates a calibration curve based on the measurement result.

[0048] Figure 6 is from Figure 5 This is an example of a calibration curve for the sample measurement device 1 obtained by a graph of . This calibration curve can be formed by obtaining the relationship between the absorbance Ab of the calibration solution Sc stored in the sample container 11 and the above-mentioned attenuation amount Da and connecting the obtained plot points. Figure 6The calibration curve is formed by simply connecting a plurality of plotted points with straight lines, but the present invention is not limited thereto, and the calibration curve may be obtained by approximate calculation using the least square method or the like. The obtained calibration curve is stored in the calibration data storage unit 19 as calibration data.

[0049] If the calibration curve is obtained and stored in the calibration data storage unit 19 as calibration data, the sample solution Sm (sample) to be measured is then injected into the sample container 11, and the measurement is performed in the same manner as in the first embodiment. That is, the irradiation light L1 is irradiated along the X direction from the first surface S1 of the sample container 11 into which the sample solution Sm is injected, and in this state, the sample solution Sm is photographed from the Y direction by the camera 14 (step S13). The image data obtained by the camera 14 is stored in a storage unit (not shown) in the calculation control unit 16. The calculation control unit 16 calculates the light intensity value (normalized) of each point in the image data obtained in step S13 and stored in the storage unit (step S14).

[0050] Then, the data of the light intensity value calculated in step S14 is compared with the calibration curve generated in step S12, and the concentration of the sample solution Sm (sample) to be measured is calculated based on the comparison result (step S15). Specifically, the attenuation Da at the point P2 and the point P3 in the image data of the sample solution Sm is measured, and the attenuation Da at the point P2 and the point P3 is calculated based on the calibration curve ( Figure 6 ) is used to determine the absorbance Ab corresponding to the attenuation amount Da. By determining the absorbance Ab, the corresponding concentration value is calculated in the calculation control unit 16. The calculated concentration value is displayed on the display 18.

[0051] As described above, according to the second embodiment, calibration data obtained by measuring a calibration solution having a known concentration is stored in the calibration data storage unit 19, and the concentration of the sample solution Sm to be measured can be accurately measured based on the calibration data.

[0052] The present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not limited to all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and in addition, the structure of other embodiments can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0053] Description of Reference Numerals

[0054] 1...sample measuring device, 11...sample container, 12...light source, 13...condensing lens, 14...camera, 15...A / D converter, 16...calculation control unit, 18...display, 19...calibration data storage unit, S1...first surface, S2...second surface, Sc (Sc1-5)...calibration solution, Sm...sample solution.

Claims

1. A sample measuring device, characterized in that: The sample measuring device comprises: a sample container containing a sample solution containing particles; a light source for irradiating light to the sample container from a first direction; an imaging unit that captures an image of the sample solution based on light scattered in the sample solution from a second direction intersecting the first direction; a calculation unit that calculates the absorbance or concentration of the sample solution based on the image, The irradiation light is irradiated from the first direction and scattered by the particles, The calculation unit calculates, based on the image, a degree of attenuation of the amount of light of the image within a fixed optical path length along the first direction, and calculates absorbance or concentration of the sample solution according to the attenuation degree.

2. The sample measuring device according to claim 1, characterized in that: The calculation unit measures the light amount of the image at a first measurement point having a first optical path length and a second measurement point having a second optical path length different from the first optical path length, and calculates the attenuation degree of the light amount of the image between the first measurement point and the second measurement point based on the measured light amount.

3. The sample measuring device according to claim 1, characterized in that: The sample measuring device further comprises a calibration data storage unit for storing calibration data. The calculation unit calculates the attenuation degree of the light amount of the image obtained for the sample solution to be measured, and calculates the absorbance or concentration of the sample solution corresponding to the attenuation degree based on the correction data.

4. The sample measuring device according to claim 3, characterized in that: The photographing unit and the computing unit are configured to sequentially inject a plurality of calibration solutions of known concentrations into the sample container, irradiate the calibration solutions with the irradiation light, perform photographing by the photographing unit, and calculate the concentration of the calibration solutions by the computing unit, thereby calculating the calibration data and storing them in the calibration data storage unit.

5. The sample measuring device according to claim 3, characterized in that: The calibration data is a calibration curve showing the relationship between absorbance and the attenuation degree of light quantity at a fixed optical path length. The calculation unit compares the attenuation degree of the light amount obtained for the sample solution with the calibration curve, thereby calculating the absorbance or concentration of the sample solution.

6. A sample determination method, characterized in that: A sample solution containing particles is placed in a sample container. irradiating the sample container with irradiation light from a first direction, and the irradiation light is scattered by the particles, capturing an image of the sample solution based on light scattered in the sample solution from a second direction intersecting the first direction, Based on the image, an attenuation degree of the light amount of the image in a fixed optical path length along the first direction is calculated, and the absorbance or concentration of the sample solution is calculated according to the attenuation degree.

7. The sample measurement method according to claim 6, characterized in that: The sample measurement method further comprises the step of measuring the light quantity of the image at a first measurement point having a first optical path length and a second measurement point having a second optical path length different from the first optical path length. The degree of attenuation of the light amount of the image between the first measurement point and the second measurement point is calculated based on the measured light amount.

8. The sample measurement method according to claim 6, characterized in that: The sample measurement method further includes the step of storing the calibration data in the calibration data storage unit. The attenuation degree of the light amount of the image obtained for the sample solution to be measured is calculated, and the absorbance or concentration of the sample solution corresponding to the attenuation degree is calculated based on the correction data.

9. The sample measurement method according to claim 8, characterized in that: The sample determination method also includes: A plurality of calibration solutions with known concentrations are sequentially injected into the sample container, The calibration solution is irradiated with the irradiation light and photographed, and the calibration data is calculated by calculating the concentration of the calibration solution and stored in the calibration data storage unit.

10. The sample measurement method according to claim 8, characterized in that: The calibration data is a calibration curve showing the relationship between absorbance and the attenuation degree of light quantity at a fixed optical path length. The absorbance or concentration of the sample solution is calculated by comparing the attenuation degree of the light amount obtained for the sample solution with the calibration curve.

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