JP2017203741A - Sensitivity correction method and quantitative measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for correcting a sensitivity with a higher accuracy and a method for quantitative measuring using the method for correcting a sensitivity.SOLUTION: According to the method, light from a light source is emitted to a reference material selected for a measurement object O so that light emitted from a reference substance S is measured by a light receiving sensor of a light receiving unit 20, and a correction expression showing a relation with the correspondence between the amount of light received by the light receiving sensor and the output value of a signal output from the light receiving sensor is calculated based on the measurement result.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sensitivity correction method and a quantitative measurement method.

  When performing sensitivity correction of a sensor that receives light from an object to be measured in an optical measurement device, the sensor output value is measured in a state in which the reference light is received and in a light-shielded state, and linear correction is performed based on this measurement. Is used. In general, light from a light source is used as it is as a reference light (for example, Patent Document 1).

JP 2010-73863 A

  However, when the relationship between the received light intensity and the output value in the sensor is not linear, it is considered that sufficient correction cannot be performed by the above linear correction. It is also conceivable that errors occur due to linear correction.

  The present invention has been made in view of the above, and an object thereof is to provide a sensitivity correction method capable of correction with higher accuracy and a quantitative measurement method using the sensitivity correction method.

The present invention is
(1) The light emitted from the reference material is measured by the light receiving sensor of the light receiving unit by irradiating the reference material selected for the measurement target with light from the light source, and based on the measurement result A sensitivity correction method for calculating a correction formula indicating a correspondence relationship between a light amount of light received by the light receiving sensor and a correspondence relationship between an output value of a signal output from the light receiving sensor;
as well as,
(2) A quantitative measurement method for calculating a concentration of a substance contained in a measurement object,
The light emitted from the reference material is measured by a light receiving sensor of a light receiving unit by irradiating light from a light source to the reference material selected for the measurement object, and based on the measurement result, Calculating a correction equation indicating a correspondence relationship between the amount of light received by the light receiving sensor and an output value of a signal output from the light receiving sensor, and performing sensitivity correction based on the correction equation;
Each of a plurality of samples with known concentrations of substances to be quantitatively measured is irradiated with light from the light source, the light emitted from the sample is measured by the light receiving sensor of the light receiving unit, and based on the measurement result And creating the calibration curve,
By irradiating the measurement object with light from a light source, measuring the light emitted from the measurement object with a light receiving sensor of a light receiving unit, and comparing the measurement result with the calibration curve, Calculating the concentration of the measurement object;
A quantitative measurement method having
It is.

  According to the present invention, a sensitivity correction method capable of correction with higher accuracy and a quantitative measurement method using the sensitivity correction method are provided.

It is a figure explaining the structure of the optical measuring device which concerns on embodiment of this invention. It is a figure explaining the conventional sensitivity correction method. It is a figure explaining the relationship between the correction formula of the conventional sensitivity correction method, and the sensitivity characteristic of a light receiving sensor. It is a figure explaining the sensitivity correction method which concerns on embodiment of this invention. It is a figure which shows the difference of the transmittance | permeability of the sugar water with the highest density | concentration among measurement objects, and the transmittance | permeability of the water which is a reference | standard substance. It is a figure explaining the example of a measurement at the time of using the conventional sensitivity correction method. It is a figure explaining the example of a measurement at the time of using the sensitivity correction method which concerns on embodiment of this invention.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described.

  In the sensitivity correction method of the present application, (1) the light emitted from the reference material is measured by the light receiving sensor of the light receiving unit by irradiating light from the light source to the reference material selected for the measurement object. Based on the measurement result, a correction formula is calculated that indicates the correspondence between the amount of light received by the light receiving sensor and the output of the signal output from the light receiving sensor.

  According to the above sensitivity correction method, by irradiating light from the light source to the reference material selected for the measurement object, based on the measurement result of light measured by the light receiving sensor of the light receiving unit, A correction formula relating to sensitivity correction of the light receiving sensor is calculated. In this way, by performing sensitivity correction using a reference substance, the accuracy of correction can be improved compared to the case where the measurement result when the light from the light source is received by the light receiving sensor is used for correction as in the past. This improves the correction with higher accuracy.

(2) Moreover, this invention is a sensitivity correction method as described in said (1), The said light reception sensor has a sensitivity with respect to the light of a certain wavelength range within 1200 nm-2350 nm.

  As described above, when the light receiving sensor has sensitivity to light in a certain wavelength range within 1200 nm to 2350 nm, it is suitably used for measurement using near infrared light.

(3) In the sensitivity correction method according to the above (1) or (2), the invention of the present application includes a plurality of light receiving sensors in the light receiving unit, and each of the plurality of light receiving sensors is mutually connected. Light having different wavelengths is incident, and a correction formula corresponding to the wavelength of the incident light is created for each of the plurality of light receiving sensors.

  As described above, when light of different wavelengths is incident on each of the plurality of light receiving sensors, a correction formula corresponding to the wavelength of the light incident on each of the light receiving sensors is created, whereby the sensitivity of each of the plurality of light receiving sensors is determined. Since correction can be performed with high accuracy, correction with higher accuracy is possible.

(4) Moreover, this invention is a sensitivity correction method as described in said (1)-(3), The said measurement object is a solution, The solvent of the said measurement object is selected as said reference | standard substance. In the present invention, the “solution” includes a macroscopically uniform dispersion solution (for example, a colloidal solution) in which two or more phases are dispersed and mixed in a microscopic state.

  As described above, when the measurement target is a solution, correction with higher accuracy is possible by selecting the solvent of the measurement target as the reference substance.

  Further, the quantitative measurement method of the present application is (5) a quantitative measurement method for calculating a concentration of a substance contained in a measurement object, wherein light from a light source is emitted with respect to a reference substance selected for the measurement object. The light emitted from the reference material is measured by the light receiving sensor of the light receiving unit, and based on the measurement result, the amount of light received by the light receiving sensor and the output value of the signal output from the light receiving sensor A correction formula indicating the correspondence relationship between the light source and the step of performing sensitivity correction based on the correction formula, and the light from the light source for each of a plurality of samples whose concentrations of the substance to be quantitatively measured are known. Irradiating and measuring the light emitted from the sample with the light receiving sensor of the light receiving unit, creating a calibration curve based on the measurement result, and irradiating the measurement object with light from a light source , The measurement pair The light emitted from the object is measured by the light receiving sensor of the light receiving section, by comparing the calibration curve and measurement result, and a step of calculating a concentration of the measurement object.

  According to the above quantitative measurement method, by irradiating the light from the light source to the reference material selected for the measurement object, based on the measurement result of the light measured by the light receiving sensor of the light receiving unit, After calculating a correction formula related to sensitivity correction of the light receiving sensor and performing sensitivity correction based on this, a process related to quantitative measurement of the concentration of the substance contained in the measurement object is performed. Thus, quantitative measurement can be performed with higher accuracy by performing quantitative measurement using a light receiving sensor that has been subjected to sensitivity correction using a reference substance.

[Details of the embodiment of the present invention]
Specific examples of the sensitivity correction method and the quantitative measurement method according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included.

  FIG. 1 is a diagram illustrating a configuration of an optical measurement apparatus 1 according to the present embodiment. The optical measuring device 1 shown in FIG. 1 irradiates the measuring object O with the measuring light L1 emitted from the light source 10, and as a result, the light emitted from the measuring object O (transmitted light L2 in the case of FIG. 1). Is detected by the light receiving unit 20, and performs measurement related to the measurement object O, and includes a light source 10, a light receiving unit 20, and an analysis unit 30. In the optical measurement apparatus 1 shown in FIG. 1, the transmitted light L2 is measured as light emitted from the measurement object O. However, the light emitted from the measurement object O may be diffuse reflection light. In that case, the arrangement of the light source 10 and the light receiving unit 20 is changed so that the diffusely reflected light can be detected.

  The measuring object O to be measured by the optical measuring device 1 is not particularly limited. However, in the case of an apparatus that detects the transmitted light L2 from the measurement object O, such as the optical measurement apparatus 1, the measurement object O can transmit the measurement light L1.

  The light source 10 of the optical measuring device 1 irradiates the measurement light L1 made of near infrared light to the region where the measurement object O is arranged. As the light source 10, a halogen lamp or the like can be used. An SC light source that includes a seed light source and a nonlinear medium, inputs light emitted from the seed light source to the nonlinear medium, broadens the spectrum by a nonlinear optical effect in the nonlinear medium, and outputs the spectrum as supercontinuum (SC) light. Can also be used as the light source 10. When an SC light source is used as the light source 10, heating by the SC light source is reduced as compared with a halogen lamp, so that it is suitable for measuring a measurement object that may be altered by heating, such as a measurement object that contains microorganisms. is there. Furthermore, the light source 10 may have a function of modulating the intensity. Further, as the light source 10, an LED or an SLD light source can be applied. With these light sources, illumination light having a pre-controlled wavelength characteristic is realized. At the same time, heating can be avoided.

  In the present embodiment, the near infrared light emitted by the light source 10 is light having a wavelength range of 1200 nm to 2350 nm. In the present embodiment, the spectrum refers to information including light intensities relating to at least two wavelengths.

  In the present embodiment, the measurement light L1 emitted by the light source 10 is not limited to near infrared light. Examples of the measurement light L1 having a wavelength range different from that of near infrared light include visible light (wavelength range 350 nm to 800 nm), infrared light (wavelength range 2500 nm or more), and the like.

  The light receiving unit 20 includes a light receiving sensor, and detects, in the light receiving sensor, transmitted light L2 that has passed through the measurement object O among the measuring light L1 emitted from the light source 10. The light receiving sensor outputs a signal having a value corresponding to the intensity of the received light. The intensity information of the transmitted light L2 detected by the light receiving sensor is sent to the analysis unit 30 as a signal output value. As the light receiving sensor, for example, an MCT detector made of mercury, cadmium and tellurium, an InGaAs detector, or the like can be used. When the measurement light L1 from the light source 10 is near-infrared light, the light receiving sensor preferably has sensitivity to near-infrared light, particularly for light in a certain wavelength range within 1200 nm to 2350 nm. It is preferable to have sensitivity.

  The light receiving unit 20 may be a spectrometer. In this case, in the light receiving unit 20, the light receiving sensors are arranged in an array, and a spectroscope is provided in front of the light receiving sensor. Then, the transmitted light L2 from the measurement object O is split by the spectroscope, and the split light is received by each of the plurality of light receiving sensors, and a signal having a value corresponding to the intensity is output for each light receiving sensor.

  The light receiving unit 20 may be a hyperspectral sensor that acquires a hyperspectral image. The hyperspectral image is an image in which one pixel is composed of N pieces of wavelength data, and includes spectral information including intensity data corresponding to a plurality of wavelengths for each pixel. That is, a hyperspectral image has a three-dimensional configuration that combines two-dimensional elements as an image and elements as spectral data because of the feature that each pixel constituting the image has intensity data of multiple wavelengths. It is data. In the present embodiment, a hyperspectral image refers to an image composed of pixels having intensity data in at least two wavelength bands per pixel.

  The analysis unit 30 receives information on the transmitted light L2 sent from the light receiving unit 20, and performs arithmetic processing and the like. In addition, it is good also as a structure by which the statistical processing etc. for performing the evaluation which concerns on the measuring object O are performed in the analysis part 30. In addition, when the light receiving unit 20 is a hyperspectral sensor, spectrum information relating to each pixel is sent to the analysis unit 30, and thus the analysis unit 30 can perform a calculation on the spectrum information. .

  In the optical measuring method by the optical measuring device 1 having the above-described configuration, the step of detecting the transmitted light L2 or the diffuse reflected light related to the measuring object O by irradiating the measuring object O with the measuring light L1. And a step of performing an evaluation related to the measurement object O based on the received light intensity of the transmitted light L2 or the diffuse reflected light in the light receiving unit 20.

  Here, the sensitivity correction of the light receiving sensor of the light receiving unit 20 in the optical measuring device 1 according to the present embodiment will be described. The sensitivity correction of the light receiving sensor in this embodiment is to define the correspondence between the amount of light received by the light receiving sensor and the output value of the signal output from the signal from the light receiving sensor, and to output the signal from the light receiving sensor. This means that the amount of light received by the light receiving sensor can be calculated from the value.

  FIG. 2 is a diagram for explaining the procedure of correcting the sensitivity of the light receiving sensor before the measurement related to the measurement object O is performed. In general, in order to stabilize the measurement accuracy of the light receiving sensor provided in the light receiving unit 20 of the optical measuring device 1, before measuring the measurement object O, as shown in FIG. Measure the output value of the light receiving sensor. Further, as shown in FIG. 2B, the output value of the light receiving sensor in a state where the reference light from the light source 10 is irradiated is measured. Here, the measurement light L1 is used as the reference light. Thereafter, as shown in FIG. 2C, the measurement object O is disposed between the light source 10 and the light receiving unit 20, and the measurement object L is irradiated with the measurement light L1. The emitted transmitted light L2 is received, and measurement related to the measurement object O is performed. As shown in FIGS. 2A and 2B, correction is performed using two output values, so that the time variation of the light amount of the reference light from the light source 10 and the time variation of the sensitivity of the light receiving sensor are reduced. The error that comes from is reduced. As a correction method using the output value of the light receiving sensor, linear correction is the most common, and the output value of the signal from the light receiving sensor in the light shielding state is set to 0%, and the light receiving sensor in the state irradiated with the reference light is used. Assuming that the output value of this signal is 100%, it is assumed that there is a linear relationship between the amount of light received by the light receiving sensor and the output value of the signal from the light receiving sensor, and light is received based on the output value of the signal from the light receiving sensor. The amount is calculated at a ratio of 0% to 100%.

  The following points are problems in the correction method using the linear correction described above. In other words, it is assumed that the amount of light received by the light receiving sensor and the output value of the signal from the light receiving sensor are in a linear relationship, but the sensitivity characteristic of the light receiving sensor may actually differ from the above assumption. It is a point. For example, consider the case where the above linear correction is performed even though the relationship between the amount of light received by the light receiving sensor and the output value of the signal from the light receiving sensor is non-linear. FIG. 3 shows a straight line indicating the relationship between the light reception amount of the light reception sensor based on the linear correction and the output value of the signal, and the light reception amount of the light reception sensor and the signal output value based on the sensitivity characteristic of the actual light reception sensor. .

  In the linear correction, a correction formula indicating a straight line indicating the relationship between the amount of received light and the output value of the signal from the light receiving sensor in the corrected light receiving sensor is the output value of the signal when the reference light is received (in FIG. 3). Based on the point P1), it is created on the assumption that the relationship of the straight line A1 in FIG. 3 is satisfied. On the other hand, when the light receiving sensor actually has the sensitivity characteristic indicated by the curve A2, a region where the straight line A1 and the curve A2 are separated from each other is generated. When the output value of the signal from the light receiving sensor is a specific value P2, the amount of light actually received by the light receiving sensor should be a value corresponding to the intersection P3 with the curve A2, but the correction equation is When used, a value corresponding to the intersection P4 with the straight line A1 is calculated. Therefore, an error occurs between the amount of light received by the light receiving sensor calculated by the correction equation and the amount of light received by the light receiving sensor. As one method for solving this problem, there is a method of preparing a correction formula closer to the sensitivity characteristic of an actual light receiving sensor by preparing a plurality of reference lights having different light amounts and creating a correction formula. However, it is difficult to completely match the correction formula with the sensitivity characteristic of the light receiving sensor.

  On the other hand, in the optical measuring device 1 according to the present embodiment, the reference material S corresponding to the measurement object O is prepared, the measurement related to the reference material S is performed, and the result is used for sensitivity correction of the light receiving sensor. It is characterized by that. The reference material S is set according to the measurement object O. For example, when the measurement object O is an aqueous solution such as a culture solution for culturing cells, it is conceivable to select water as the main component of the measurement object O as the reference substance S. Thus, as the reference substance S, it is conceivable to select a component that becomes a solvent of the measurement object O. Moreover, it is preferable that the reference substance S is selected so that the transmittance (or diffuse reflectance) when the light having the same output intensity as that of the light source 10 of the optical measuring device 1 is irradiated is known. However, even if the transmittance (or diffuse reflectance) when irradiating light having the same output intensity is unknown, the characteristics with respect to light of the wavelength to be measured (transmittance or diffuse reflectance with respect to the light source 10) Can be selected as the reference material S when it is known in advance that the material is similar to the measurement object O. From the viewpoint that characteristics with respect to light of a wavelength to be measured are similar to that of the measurement object O, it is considered to be one preferable choice to select the solvent of the measurement object O as the reference substance S.

  FIG. 4 is a diagram for explaining the procedure of correcting the sensitivity of the light receiving sensor before the measurement related to the measurement object O is performed. When the correction using the reference substance S is performed, as shown in FIG. 4A, first, the output value of the light receiving sensor in the light shielding state is measured. Next, as illustrated in FIG. 4B, the reference material S is disposed between the light source 10 and the light receiving unit 20, and the measurement related to the reference material S is performed. Thereafter, as illustrated in FIG. 4C, the measurement object O is disposed between the light source 10 and the light receiving unit 20, and measurement related to the measurement object O is performed. That is, unlike the conventional method in which the measurement value L1 is directly detected by the light receiving sensor, the output value is measured, and correction is performed using this, the transmitted light L3 transmitted through the reference substance S is detected by the light receiving sensor. The output value is measured and used for correction.

  One of the correction methods is a method of handling the transmitted light L3 transmitted through the reference material S as the reference light. That is, the output value of the signal from the light receiving sensor in the light shielding state is set to 0%, and the output value of the signal from the light receiving sensor in the state of receiving the transmitted light L3 transmitted through the reference material S is set to 100%. Assuming that the amount of received light and the output value of the signal from the light receiving sensor have a linear relationship, a method of calculating the received light amount at a ratio of 0% to 100% based on the output value of the signal from the light receiving sensor Can be mentioned. The point of performing linear correction is the same as the conventional correction method, but the amount of light received by the light receiving sensor serving as a reference for the correction formula is similar to that of the measurement object O, and therefore near the transmittance of the measurement object O. This is considered to improve the accuracy of the correction formula.

  As another method of correction using the reference substance S, when the transmittance (or diffuse reflectance) of the reference substance S with respect to light of the wavelength to be detected in the light receiving sensor is known, The relationship between the output value of the signal from the light receiving sensor and the transmittance when the transmitted light L3 is irradiated may be specified, and this may be applied to the correction equation. That is, the output value of the signal from the light receiving sensor in the light shielding state is set to 0%, and the output value of the signal from the light receiving sensor in the state where the transmitted light L3 from the reference substance S having the transmittance x% is irradiated is set to x%. This is a method of correcting by calculating a correction formula from these relationships. Even in this case, the accuracy of the correction formula in the vicinity of the transmittance of the measurement object O is higher than that in the case where the correction formula is calculated by setting the output value of the signal from the light receiving sensor in the state where the reference light is irradiated to 100%. It is thought to improve.

  In the above two correction methods, the output value of the signal from the light receiving sensor in a state where the transmitted light L3 from the reference material S is received is set to 100%, or a value corresponding to the transmittance of the reference material S. However, in any case, the transmission of the measuring object O is compared with the case where the correction expression is calculated with the output value of the signal from the light receiving sensor in the state of irradiation of the reference light as 100%. It is considered that the accuracy of the correction formula near the rate is improved.

  A plurality of reference substances S may be set. When a correction equation is created using a plurality of substances whose reference substance S has similar transmittance (or diffuse reflectance) to the light of the wavelength to be detected in the light receiving sensor as the measurement object O, the measurement is performed. It is conceivable that the accuracy of the correction formula near the transmittance of the object O is further improved.

  When the light receiving unit 20 includes a plurality of light receiving sensors, a correction formula is created for each light receiving sensor. The light receiving sensor has different sensitivity characteristics for each individual, but by making use of the transmitted light L3 from the reference substance S and creating a correction formula for each light receiving sensor, correction can be made in consideration of the sensitivity characteristics for each light receiving sensor. It becomes.

  In addition, when the light receiving unit 20 is a spectroscopic measuring device, light having different wavelengths separated from each other is incident on the plurality of light receiving sensors with respect to the light receiving sensors arranged in an array. Accordingly, different correction formulas are created for each wavelength of incident light in each of the plurality of light receiving sensors. By adopting such a configuration, it is possible to perform correction with higher accuracy in each of the plurality of light receiving sensors. If the spectrum shape of the reference substance S used for sensitivity correction is similar to the spectrum shape of the measurement object O, the accuracy of correction in each light receiving sensor is further increased.

  Here, in the optical measuring device 1, the correction with higher accuracy can be performed by performing the correction related to the output value of the signal from the light receiving sensor using the reference substance S, referring to the following examples. While explaining.

  Here, an example of measuring two types of sugar water having different concentrations enclosed in a glass cell having a thickness of 1 mm using a near-infrared spectroscopic device that detects transmitted light similar to the optical measurement device 1 shown in FIG. Will be described.

The output value of the signal from the light receiving sensor when the reference light is input to the light receiving sensor of the near-infrared spectrometer is set to 100%, the output value of the signal from the light receiving sensor in the light shielding state is set to 0%, After performing linear correction assuming that the relationship between the amount of received light and the output value is a linear relationship, the amount of light absorption at the characteristic absorption wavelength (1570 nm) of sugar (the ratio of the amount of transmitted light after passing through sugar water to the amount of input light) Measured. Two types of light, reference light A and reference light B, were assumed as the reference light. The reference light A corresponds to a conventional correction method, and the reference light B corresponds to a sensitivity correction method according to the present embodiment. Water, which is a solvent for sugar water, was used as the reference material S because it has almost the same light transmission characteristics as sugar water.
Reference light A: The light emitted from the light source 10 is directly input to the light receiving unit 20 as the reference light A.
Reference light B: A glass cell in which pure water is sealed is placed between the light source 10 and the light receiving unit 20, and the light that has passed through the pure water (corresponding to the reference substance S) in the glass cell is used as the reference light B. 20 to input.

  FIG. 5 shows the difference between the transmittance of sugar water having the highest concentration among the following measurement objects and the transmittance of water as a reference substance. From 1200 nm to 2350 nm, the transmittance difference was within 2%.

  The following measurements were performed after correcting each of the above two types of reference light.

First, four types of sugar waters having different concentrations were prepared, and each was measured 10 times with the same amount of light output from the light source 10 (I ₀ ). The amount of light absorption after linear correction was calculated from the output value of the signal from the light receiving sensor.

Next, in the state where the output light amount from the light source 10 is attenuated by 5%, in the same manner as above, the output light amount from the light source 10 is the same (I ₀ × 95%) for each of the four types of sugar. It was measured once. The amount of light absorption after linear correction was calculated from the output value of the signal from the light receiving sensor. The sensitivity correction of the light receiving sensor was performed for each measurement, and the sensitivity correction was performed using the light attenuated by 5% before the measurement using the light attenuated by 5%.

The results are shown in FIGS. FIG. 6 shows the result when the sensitivity correction of the light receiving sensor is performed using the reference light A, and FIG. 7 shows the result when the sensitivity correction of the light receiving sensor is performed using the reference light B. 6 and 7, the horizontal axis represents the sugar water concentration, and the vertical axis represents the light absorption amount calculated from the output value of the light receiving sensor. 6 is compared with FIG. 7, in FIG. 6, when the output light amount from the light source 10 is attenuated by 5%, the relationship between the concentration of sugar water and the light absorption amount changes from that before the attenuation (I ₀ ) ( It was confirmed that the slope of the approximate line changes). On the other hand, in FIG. 7, even if the output light amount from the light source 10 is attenuated by 5%, the relationship between the concentration of sugar water and the amount of light absorption does not substantially change from that before attenuation (I ₀ ). It was confirmed that the inclination was almost unchanged. As described above, by using the transmitted light L3 transmitted through the reference substance S as the light used for correction of the light receiving sensor, it is possible to perform sensitivity correction capable of correction with higher accuracy.

  In addition, when quantitative measurement related to the measurement object O is performed using the optical measurement apparatus 1 that has performed the above sensitivity correction, quantitative measurement with higher accuracy becomes possible.

  As a quantitative measurement, a quantitative measurement method for measuring the concentration of a specific substance contained in the measurement object O includes the following steps. That is, the light emitted from the reference material S is irradiated to the reference material S selected for the measurement object O to be quantitatively measured, and the light received from the reference material S is received by the light receiving sensor of the light receiving unit 20. Based on the measurement result, calculate a correction formula indicating the correspondence between the amount of light received by the light receiving sensor and the output value of the signal output from the light receiving sensor, and perform sensitivity correction based on the correction formula. Irradiating light from the light source 10 to each of a plurality of samples whose concentrations of substances to be quantitatively measured are known, and measuring the light emitted from the sample by the light receiving sensor of the light receiving unit 20 A step of creating a calibration curve based on the result, and the light emitted from the light source 10 is applied to the measurement object O, whereby the light emitted from the measurement object is measured by the light receiving sensor of the light receiving unit 20 and measured. Results and calibration curve By comparison, and a step of calculating a concentration of the measurement object.

  By performing the above quantitative measurement with the optical measurement apparatus 1 that performs sensitivity correction of the light receiving sensor of the light receiving unit 20 using the reference substance S, measurement using the light receiving sensor that has been corrected in accordance with the sensitivity characteristic can be performed. Therefore, quantitative measurement with higher accuracy is possible.

  As described above, according to the sensitivity correction method according to the present embodiment, the light receiving sensor of the light receiving unit 20 irradiates the light from the light source 10 to the reference material S selected for the measurement object O. Based on the measurement result of the light to be measured, a correction formula for correcting the sensitivity of the light receiving sensor is calculated. In this way, by performing sensitivity correction using the reference substance S, the accuracy of correction can be improved as compared with the case where the measurement result when the light from the light source is received by the light receiving sensor is used for correction as in the past. Thus, correction with higher accuracy becomes possible.

  Further, since the light receiving sensor of the light receiving unit 20 has sensitivity to light in a certain wavelength range within 1200 nm to 2350 nm, it is suitably used for measurement using near infrared light.

  In addition, when light of different wavelengths is incident on each of the plurality of light receiving sensors, a correction formula corresponding to the wavelength of the light incident on each of the light receiving sensors is created to accurately perform sensitivity correction in each of the plurality of light receiving sensors. Since it can be performed well, correction with higher accuracy becomes possible.

  When the measurement object O is a solution, correction with higher accuracy is possible by selecting the solvent of the measurement object O as the reference material S.

  Further, according to the quantitative measurement method according to the present embodiment, measurement is performed by the light receiving sensor of the light receiving unit 20 by irradiating light from the light source 10 to the reference material S selected for the measurement object O. Based on the measurement result of light, a correction formula related to the sensitivity correction of the light receiving sensor is calculated, and after the sensitivity correction is performed based on this, a process related to quantitative measurement of the concentration of the substance contained in the measurement object O is performed. Done. Thus, quantitative measurement can be performed with higher accuracy by performing quantitative measurement using a light receiving sensor that has been subjected to sensitivity correction using the reference substance S.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the case where only one light source 10 is provided has been described, but a plurality of light sources 10 may be provided. In particular, when the optical measuring device is a device that measures diffuse reflected light, the amount of light received by the light receiving unit 20 can be increased by increasing the number of light sources 10. Further, the light source 10 itself may be capable of changing the amount of light. Furthermore, the light source 10 does not have to be a point light source. For example, when the light receiving unit 20 is a so-called line sensor, the light source 10 may be configured to employ a linear light source.

  DESCRIPTION OF SYMBOLS 1 ... Optical measuring device, 10 ... Light source, 20 ... Light-receiving part, 30 ... Analysis part, O ... Measuring object, S ... Reference material.

Claims (5)

  The light emitted from the reference material is measured by the light receiving sensor of the light receiving unit by irradiating light from the light source to the reference material selected for the measurement object, and the light reception is performed based on the measurement result. A sensitivity correction method for calculating a correction formula indicating a correspondence relationship between a light amount of light received by the sensor and a correspondence relationship between an output value of a signal output from the light receiving sensor.   The sensitivity correction method according to claim 1, wherein the light receiving sensor has sensitivity to light in a certain wavelength range within 1200 nm to 2350 nm. The light receiving unit is provided with a plurality of light receiving sensors,
Light of different wavelengths is incident on each of the plurality of light receiving sensors,
The sensitivity correction method according to claim 1, wherein a correction expression corresponding to a wavelength of incident light is created for each of the plurality of light receiving sensors. The measurement object is a solution,
The sensitivity correction method according to any one of claims 1 to 3, wherein a solvent of the measurement object is selected as the reference substance. A quantitative measurement method for calculating the concentration of a substance contained in a measurement object,
The light emitted from the reference material is measured by a light receiving sensor of a light receiving unit by irradiating light from a light source to the reference material selected for the measurement object, and based on the measurement result, Calculating a correction equation indicating a correspondence relationship between the amount of light received by the light receiving sensor and an output value of a signal output from the light receiving sensor, and performing sensitivity correction based on the correction equation;
Each of a plurality of samples with known concentrations of substances to be quantitatively measured is irradiated with light from the light source, the light emitted from the sample is measured by the light receiving sensor of the light receiving unit, and based on the measurement result Creating a calibration curve,
By irradiating the measurement object with light from a light source, measuring the light emitted from the measurement object with a light receiving sensor of a light receiving unit, and comparing the measurement result with the calibration curve, Calculating the concentration of the measurement object;
A quantitative measurement method comprising:

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