JP5947761B2 - Component concentration analyzer and component concentration analysis method - Google Patents

Description

  The present invention relates to a technique for non-invasively measuring a human or animal component concentration.

  There is a component concentration analyzer that measures a component concentration such as a blood sugar level without collecting blood (Patent Document 1). A photoacoustic method is used in which an electromagnetic wave is irradiated into the skin to be absorbed by a blood component, thermally expanded locally by heat radiation from the blood component, and a sound wave generated from the living body due to the thermal expansion is observed.

Specifically, two intensity-modulated lights having wavelengths λ ₁ and λ ₂ having opposite phases are combined and output to the object to be measured. Then, a sound wave generated by being absorbed by the component of the measurement object is detected, and the concentration of the measurement target component in the measurement object is measured from the magnitude of the sound wave.

Here, for example, the wavelength λ ₁ and the wavelength λ ₂ are set so that the absorbance by water as a background component in the object to be measured is equal to each other. The wavelength λ ₁ is set so that the absorbance due to glucose, which is a measurement target component in the object to be measured, is maximized.

If emitted light of such two different wavelengths, and the sound waves of light of wavelength lambda ₁ is both glucose and water generated from the absorber to the object to be measured, the wavelength lambda ₂ light absorbed water under Since the sound wave generated from the measurement object has the same frequency and opposite phase, it is superimposed inside the measurement object, and only the magnitude of the sound wave generated from the measurement object as glucose is absorbed as glucose difference. Remains.

That is, the detected wave magnitude A _d is the sound wave was measured using only the light of wavelength lambda ₁ magnitude A ₁ and wavelength lambda ₂ of the acoustic wave was measured using only light magnitude of the A ₂ It corresponds to the difference and is based on the absorption of glucose alone.

Further, since _Ad is proportional to the product of the magnitude I of light irradiating the object to be measured and the absorbance α of the object to be measured, Expression (1) is established. C is a proportional coefficient including an error factor of the sound wave measurement system.

A _d = C × (α × I) (1)
Furthermore, the absorbance α of the object to be measured is considered to be equal to the absorbance α ^(g) of light due to glucose, as shown in Equation (2), because the absorbance α ^(w) of light due to water cancels out due to the difference detection. be able to.

α = α ^(g) + α ^(w) = α ^(g) (2)
The deformed by substituting equation (2) into equation (1) obtains the value of the equation (3) after deformation by substituting the value of each of A _d and C 'alpha ^(g), it was determined The component concentration of glucose is calculated from α ^(g) .

α ^(g) = A _d ÷ (C × I) = A _d ÷ C ′ (3)
At this time, C ′ including I is a coefficient that is difficult to control or predict. For example, acoustic coupling, sensitivity of sound wave detector, distance between light emitting end and object to be measured, specific heat of object to be measured, coefficient of thermal expansion of object to be measured, sound velocity at object to be measured, oscillation frequency of oscillator The unknown is also dependent on the absorbance of the object to be measured.

Therefore, conventionally, the proportionality coefficient C ′ is standardized by the magnitude A ′ of the normalizing sound wave detected by using one of the two lights. In other words, the sound wave for normalizing 'the proportionality coefficient C' size A and the A _d were seeking α and ^(g) is divided by A '.

  For reference, FIG. 9 shows a processing flow of a conventional component concentration analysis method.

JP 2007-89662 A

  However, since the proportionality coefficient C ′ is standardized on the premise that it does not depend on the absorbance α, the proportionality coefficient C ′ is strong to the absorbance α due to the generation of the resonance mode in the cavity including the sound wave measurement system or the object to be measured. If it depends, there is a problem that the proportionality coefficient C ′ cannot be normalized and a quantitative error occurs.

  That is, the amplitude and phase of the detected sound wave depend on the size of the cavity and the internal structure of the object to be measured due to acoustic resonance in the object to be measured. For this reason, the amplitude and phase of the detected sound wave change due to these fluctuations, resulting in a quantitative error.

  The present invention has been made in view of the above circumstances, and an object thereof is to improve the measurement accuracy of the component concentration of the measurement target component.

  The component concentration analyzer according to claim 1 includes an optical output unit that outputs light of two different wavelengths that are intensity-modulated by signals having opposite phases at the same frequency, and an optical combining unit that combines the two lights. A wave means, a light irradiating means for irradiating the object to be measured with the combined light or only one light, a sound wave detecting means for detecting a sound wave generated inside the object to be measured by the irradiation, and the detected Component concentration calculating means for calculating the concentration of the measurement target component in the object to be measured using a photoacoustic signal based on the magnitude of the sound wave, and the component concentration calculating means calculates the wavelength of the one light. A change in the normalization photoacoustic signal detected when swept in a predetermined wavelength range is obtained, and a ratio of the change in the normalization photoacoustic signal to an absorbance change in the wavelength range is calculated and combined. Detected when irradiated with light The calculated absorbance of the measurement target component, and subject matter to calculate the concentration of the measurement target component based on the absorbance by dividing by the ratio No..

  The component concentration analyzer according to claim 2 is the component concentration analyzer according to claim 1, wherein the component concentration calculation means further uses the amount of change in absorbance of the measurement target component due to a temperature change. The gist is to calculate the concentration of the component.

  The component concentration analyzer according to claim 3 is the component concentration analyzer according to claim 1 or 2, wherein the component concentration calculation means detects a plurality of photoacoustics for normalization detected when the frequency is varied. The gist is to identify the frequency of the photoacoustic signal having the largest ratio from the signal and calculate the concentration of the measurement target component based on the absorbance of the measurement target component obtained using the light of the frequency.

  The component concentration analyzer according to claim 4 is the component concentration analyzer according to any one of claims 1 to 3, wherein the component concentration calculation means is configured so that the component concentration in the measurement object is greater than the change in absorbance of the measurement target component. The gist is to sweep in a wavelength range where the absorbance change of the component to be measured is large.

  The component concentration analyzer according to claim 5 is the component concentration analyzer according to any one of claims 1 to 4, wherein the two wavelengths have the same absorption of the component to be measured in the object to be measured. The gist is that one of the two wavelengths is set so that the absorption exhibited by the measurement target component is maximized.

  The component concentration analysis method according to claim 6 includes: an optical output step of outputting light of two different wavelengths that are intensity-modulated by signals of opposite phases at the same frequency; and an optical combining that combines the two lights. A wave step, a light irradiation step of irradiating the object to be measured with the combined light or only one light, a sound wave detection step for detecting a sound wave generated inside the object to be measured by the irradiation, and the detected A component concentration calculating step for calculating the concentration of the measurement target component in the object to be measured using a photoacoustic signal based on the magnitude of the sound wave, and the component concentration calculating step calculates the wavelength of the one light. Obtaining a change in the normalization photoacoustic signal detected when swept in a predetermined wavelength range, calculating a ratio of the change in the normalization photoacoustic signal to an absorbance change in the wavelength range; and Wave Dividing the photoacoustic signal detected when the light is irradiated by the ratio to obtain the absorbance of the measurement target component, and calculating the concentration of the measurement target component based on the absorbance. This is the gist.

  The component concentration analysis method according to claim 7 is the component concentration analysis method according to claim 6, wherein the component concentration calculation step further uses the amount of change in absorbance of the measurement target component due to a temperature change. The gist is to calculate the concentration of the component.

  The component concentration analysis method according to claim 8 is the component concentration analysis method according to claim 6 or 7, wherein the component concentration calculation step includes a plurality of normalization photoacoustics detected when the frequency is varied. The gist is to identify the frequency of the photoacoustic signal having the largest ratio from the signal and calculate the concentration of the measurement target component based on the absorbance of the measurement target component obtained using the light of the frequency.

  As described above, according to the present invention, the change of the normalization photoacoustic signal detected when the wavelength of one light is swept in the predetermined wavelength range is obtained, and the normalization light with respect to the absorbance change in the wavelength range is obtained. Calculate the ratio of the change in the acoustic signal and divide the photoacoustic signal detected when the combined light is irradiated by the ratio to obtain the absorbance of the component to be measured in the object to be measured. The measurement accuracy of the component concentration of the component can be improved.

  According to the present invention, the measurement accuracy of the component concentration of the measurement target component can be improved.

It is a figure which shows the basic composition of the component concentration analyzer which concerns on 1st Embodiment. It is a figure which shows the processing flow of the component concentration analysis method which concerns on 1st Embodiment. It is a figure which shows the light absorption spectrum characteristic of water and glucose aqueous solution. It is a figure which shows the relationship between the light absorbency which concerns on 1st Embodiment, and the amplitude of the photoacoustic signal for normalization. It is a figure which shows the absorbance temperature dependence characteristic of glucose aqueous solution. It is a figure which shows the basic composition of the component concentration analyzer which concerns on 2nd Embodiment. It is a figure which shows the processing flow of the component concentration analysis method which concerns on 2nd Embodiment. It is a figure which shows the relationship between the light absorbency which concerns on 2nd Embodiment, and the amplitude of the photoacoustic signal for normalization. It is a figure which shows the processing flow of the conventional component concentration analysis method.

  In the present invention, the measurement accuracy of the component concentration of the measurement target component is improved by calibrating the proportional coefficient of the photoacoustic signal with respect to the change in the sound source distribution due to the change in absorbance of the object to be measured.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a basic configuration of a component concentration analyzer 1 according to the first embodiment. This component concentration analyzer 1 includes an oscillator 101, a first drive circuit 102, a first light source 103, a 180 ° phase shifter 104, a second drive circuit 105, a second light source 106, The optical multiplexer 107, the sound wave detector 109, the amplifier 110, the waveform observer 111, and the recording / calculating device 112 are configured. This will be described below.

  The oscillator 101 outputs a modulation signal for intensity-modulating each light output from the first light source 103 and the second light source 106. The 180 ° phase shifter 104 inverts one of the modulation signals from the oscillator 101 and outputs the result.

  The first drive circuit 102 drives the first light source 103 based on the modulation signal from the oscillator 101. The second drive circuit 105 drives the second light source 106 based on the modulation signal inverted by the 180 ° phase shifter 104.

The first light source 103 modulates the intensity of the light having the wavelength λ ₁ by the signal from the first driving circuit 102 and outputs the light. The second light source 106 modulates the intensity of the light having the wavelength λ ₂ by the signal from the second drive circuit 105 and outputs the light. As a result, light of two different wavelengths can be output after being electrically intensity-modulated with signals having the same frequency and opposite phase. The wavelength lambda ₂ is variably.

Here, the wavelength λ ₁ and the wavelength λ ₂ are set so that the absorption exhibited by the background component (the component to be measured) constituting the object to be measured 3 is equal to each other. For example, when the object to be measured 3 is a living body and the measurement target component is glucose or cholesterol, the absorbance by water indicating most of the object to be measured 3 is the same wavelength.

The wavelength λ ₁ is set so that the absorption exhibited by the measurement target component is maximized. For example, the wavelength that is best absorbed by glucose or cholesterol. It is preferable that it is 1600 nm or 2100 nm. At this time, continuous light output from the first light source 103 serves as measurement light, and continuous light output from the second light source 106 serves as reference light.

  The first light source 103 and the second light source 106 may be any light source that can change the wavelength and can output light whose intensity is continuously modulated. For example, a DFB (Distributed Feedback) semiconductor laser can be used. When using a wavelength tunable laser, there are a method of changing the oscillation frequency by adjusting the temperature, a method of using an external resonator, and the like. In addition, a solid-state laser can also be used, and a predetermined wavelength may be extracted using a dispersion element such as a prism or a diffraction grating.

  The optical multiplexer 107 combines the measurement light from the first light source 103 and the reference light from the second light source 106, and combines the combined light or one of the light that is not combined (the measurement light or the reference light). Only the light) is guided to the light emitting end at the front end by the optical fiber 108 and irradiated to the object 3 to be measured. A right-angle prism, an optical fiber collimator, a filler, or the like may be bonded to the light emitting end in accordance with the surface shape of the device under test 3.

  The sound wave detector 109 is disposed at a certain distance from the light emitting end of the optical multiplexer 107, detects the sound wave generated inside the DUT 3 by the light emitted from the optical multiplexer 107, and the sound wave Is converted into an electric signal proportional to the magnitude (amplitude) of the signal and output as a photoacoustic signal. For example, a microphone or a piezoelectric element can be used.

Specifically, when a voltage is supplied to the first drive circuit 102 and the second drive circuit 105 from a low-voltage power supply (not shown), a sound wave is detected using the synthesized light, and the measurement light and reference A differential photoacoustic signal S _d having a magnitude A _d as a difference from light is output. When a voltage is supplied only from the low-voltage power supply to the second drive circuit 105, the sound wave is detected using only the reference light, and the normalization photoacoustic signal _Sr is output.

  The amplifier 110 amplifies the photoacoustic signal output from the sound wave detector 109. The waveform observer 111 measures the amplitude and phase of the amplified photoacoustic signal. In addition to the waveform observer 111, the amplitude and phase of the photoacoustic signal may be measured by detection and amplification using a phase detection amplifier.

The recording / calculating device 112 includes a database that stores the absorbance spectrum of each of the background component (measurement target component) and the measurement target component constituting the DUT 3, and the measured differential photoacoustic signal The concentration of the measurement target component is calculated from the amplitude and phase of S _d and the normalization photoacoustic signal S _r . For example, a computer equipped with a memory and a CPU can be used.

  Next, a component concentration analysis method performed by the component concentration analyzer 1 will be described. FIG. 2 is a diagram showing a processing flow of the component concentration measuring method.

First, by operating only the second light source 106 is a wavelength tunable light source, the wavelength lambda ₂ is swept in a predetermined wavelength range, as detected photoacoustic signal normalized for photoacoustic signal S _r during its sweep The change is measured by the waveform observer 111 and the recording / calculation device 112 (step S101).

  Here, FIG. 3 shows the absorbance spectrum characteristics of water and an aqueous glucose solution at room temperature. The vertical axis represents the absorbance α, and the horizontal axis represents the light wavelength λ. Further, the solid line shows the water absorbance characteristics, and the broken line shows the absorbance characteristics of the glucose aqueous solution.

In the present embodiment, the wavelength range is from the wavelength λ ₂₀ to the wavelength λ _{21 in} the 1.3 μ band where the change in the absorbance of water is large. The wavelength range may be a range in which the change in absorbance of water is sufficiently larger than the change in absorbance with respect to the component concentration to be analyzed, and is, for example, in the range of several nanometers to several tens of nanometers. In particular, in the 1.3 μ band, for example, a range of several nanometers in which a change in absorbance corresponding to ten times the physiological blood glucose level occurs may be used.

The wavelength range may be either the 1.3 μ band on the short wavelength band side or the 1.5 μ band on the long wavelength band side. That is, as shown in FIG. 3, the wavelength range from the wavelength λ _{20 ′} to the wavelength λ _{21 ′} in the 1.5 μ band may be set, and further, the first light source 103 may be a wavelength tunable light source.

Here, FIG. 4 shows the relationship between the absorbance α and the magnitude A _r of the normalization photoacoustic signal S _r when the wavelength range from the wavelength λ ₂₀ to the wavelength λ ₂₁ is set. The vertical axis represents the magnitude A _r normalized for photoacoustic signal S _r, the horizontal axis represents the absorbance alpha. As the absorbance, a known absorbance spectrum value measured in advance with a spectroscope or the like is used.

As can be seen from FIG. 4, the absorbance α of the DUT 3 and the magnitude A _{r of the} normalization photoacoustic signal S _r are in a proportional relationship. That is, A _r = C × (α × I) = C ′ × α is established as shown in the above-described equation (1).

Therefore, next, in the recording / arithmetic apparatus 112, by using the measurement result of step S101, the ratio of the change in the normalization photoacoustic signal _{Sr to} the change in the absorbance α is directly obtained by the least square method or the like. The above-described proportionality coefficient C ′ is calculated and recorded (step S102).

That is, in the past, the proportionality coefficient C ′ was standardized by the size of the normalizing sound wave A ′, but in this embodiment, the ratio of the change in the normalization photoacoustic signal _{Sr to} the change in the absorbance α is proportional. The coefficient is C ′.

  The magnitude I of the light irradiating the object to be measured 3 may be detected and recorded by a photodetector and then calibrated, or the output voltage from the second light source 106 may be monitored by monitoring the output voltage of the photodetector. You may control so that it may become fixed.

Next, the first light source 103 and the second light source 106 are operated together, and light obtained by combining the measurement light having the wavelength λ _{1 and} the reference light having the wavelength λ ₂ is emitted from the optical multiplexer 107, and the combined light is used. detecting the acoustic waves generated inside the object to be measured 3 at sonic detector 109 measures the size of a _d of the differential photoacoustic signal S _d based on the sonic waveform observation device 111 recorded by the recording and computation apparatus 112 (Step S103).

Here, in the present embodiment, the wavelength λ ₁ and the wavelength λ ₂ are set so that the absorbance by water occupying most of the DUT 3 is equal to each other. The wavelength λ ₁ is set so that the absorbance by glucose is maximized. When light of two different wavelengths is emitted, only the magnitude of the sound wave generated from the object to be measured is detected by glucose, so that the differential photoacoustic signal S based on the difference between the measurement light and the reference light is detected. The magnitude _Ad of _d is measured.

Next, in the recording / arithmetic unit 112, the magnitude A _{d of} the differential photoacoustic signal S _d measured in step S103 and the proportionality coefficient C ′ calculated in step S102 are substituted into the above equation (3). By calculating the light absorbance α ^(g) (= A _d ÷ C ′) of light by glucose (step S104), the molar concentration M of the DUT 3 is calculated from the equation (4) (step S105). . α ₀ ^(g) is a known value obtained in advance by a spectroscope or the like.

M = α ^(g) ÷ α ₀ ^(g) (4)
Incidentally, each time a new measurement may be obtained molarity M according to equation (4), in case of further continuously measures the difference photoacoustic signal S _d of the magnitude A _d absorbance change Δα from the change in ^(G) may be calculated from equation (5).

Δα ^(g) = ΔA _d ÷ C ′ (5)
Δα ^(g) corresponds to the product of the molar concentration change ΔM of the object 3 to be measured and the molar absorbance α ₀ ^(g) as shown in the equation (6). Substituting the calculation result of equation (5) into 7), the change in glucose molar concentration ΔM is calculated.

Δα ^(g) = ΔM × α ₀ ^(g) (6)
ΔM = Δα ^(g) ÷ α ₀ ^(g) (7)
The component concentration analysis method has been described above. Note that the proportionality coefficient C ′ may be obtained before the execution of steps S103 to S105, or may be obtained for each measurement after S103.

Further, regardless of the equation (4), the actual blood measurements, after obtaining the initial value of the molar concentration M, by measuring the change in .DELTA.A _d of the magnitude of the difference photoacoustic signal S _d, the object to be measured 3 The molar concentration change ΔM may be obtained.

  Here, the absorbance spectrum of the background component and the measurement target component varies depending on the temperature depending on the value of the wavelength λ. FIG. 5 shows the absorbance temperature dependency characteristics of the aqueous glucose solution. The vertical axis indicates the absorbance α, and the horizontal axis indicates the temperature temp.

If the absorbance changes greatly due to temperature changes, for example, the absorbance change Δα _temp ^(g) of glucose due to temperature changes is directly measured and obtained from a known absorbance spectrum, or the temperature change ΔT is estimated from light absorption. Thus, it is determined from a known absorbance spectrum.

In this case, since Equation (6) can be described as Δα ^(g) = ΔM × α ₀ ^(g) + Δα _temp ^(g) , the change in glucose molar concentration ΔM is calculated using Equation (8) obtained by modifying it. .

ΔM = (Δα ^(g) −Δα _temp ^(g) ) ÷ α ₀ ^(g) (8)
As described above, according to the present embodiment, a change in the normalization photoacoustic signal S _r detected when the wavelength λ ₂ of the light from the second light source 106 is swept in a predetermined wavelength range is obtained. the ratio of the change in normalized for photoacoustic signal S _r relative to the change in absorbance in the wavelength range was calculated as the proportional coefficient C ', the proportional differential photoacoustic signal S _d which is detected when irradiated with combined beam By dividing by the coefficient C ′, the light absorbance α ^(g) due to glucose or the like in the object to be measured is obtained. Therefore, the quantitative error of measurement is reduced, and the measurement accuracy of the component concentration of the measurement target contained in the human or animal can be improved.

[Second Embodiment]
Next, a second embodiment will be described. FIG. 6 is a diagram showing a basic configuration of the component concentration analyzer 1 according to the second embodiment. In the component concentration analyzer 1, the frequency of the oscillator 101 is variable, and the other configuration is the same as that of the first embodiment.

There is a possibility that a plurality of resonance modes are formed inside the DUT 3. Further, proportional in each resonance mode between the size A _r normalized for photoacoustic signal S _r coefficient C 'is different. Therefore, in the present embodiment, the modulation frequency f is changed, and the magnitude A _{r of the} normalization photoacoustic signal S _r satisfies a predetermined signal-to-noise ratio (SN ratio), but the most proportional coefficient between the resonance modes. Optimization is performed by selecting a mode in which C ′ is large, that is, the most sensitive.

  Specifically, first, the SN ratio is determined from the ratio between the absorbance of the background component and the absorbance of the DUT 3. For example, it is determined to be about 1000 or more from the absorbance ratio of water and physiological glucose concentration.

Then, while sweeping the frequency f of the oscillator 101, the relationship between the absorbance α and the magnitude A _r of the normalization photoacoustic signal S _r as shown in FIG. 4 is measured within the determined SN ratio range. The frequency f _{max at} which the proportionality coefficient C ′ is maximized while satisfying the SN ratio is obtained. Then, the frequency f _max is set as the measurement frequency in the oscillator 101, and Steps S103 to S105 shown in FIG. 2 are executed.

  Hereinafter, the component concentration analysis method according to the present embodiment will be described with reference to FIG.

First, it changes the frequency f of the oscillator 101 to _{f 1} (step S201). Next, the same processing as Step S101 to Step S102 is executed (Step S202 to Step S203), and Step S201 to Step S203 are repeatedly executed until the upper limit of the frequency f is changed (Step S204).

FIG. 8 shows the relationship between the absorbance α measured at this time and the magnitude A _r of the normalization photoacoustic signal S _r . For example, when the frequency f of the oscillator 101 is changed to f _{1 to} f ₃ and measurement is performed, the normalization photoacoustic signal S _r corresponding to each frequency is measured.

Therefore, next, in the recording / arithmetic unit 112, the proportional coefficients C ₁ ′ to C ₃ ′ corresponding to the plurality of standardized photoacoustic signals S _r are obtained, and the plurality of proportional coefficients C ₁ ′ to The frequency f _max of the normalization photoacoustic signal S _r corresponding to the proportional coefficient C ′ having the maximum value among C ₃ ′ is specified and set as the measurement frequency in the oscillator 101 (step S205). Thereafter, processing similar to that in step 103 to step S105 is executed (step S206 to step S208).

From the above, according to this embodiment, the largest normalized for photoacoustic signal S _r of the proportional coefficient C 'from a plurality of photoacoustic signal normalized S _r detected upon varying the frequency f frequency f _{Since max} is specified and the light absorbance α ^(g) due to glucose or the like is obtained using the frequency f _max , a large amplitude change can be obtained even with a small change in absorbance, thereby improving sensitivity and lowering the limit of quantification. And the measurement accuracy of the component concentration of the measurement target can be further improved.

DESCRIPTION OF SYMBOLS 1 ... Component concentration analyzer 101 ... Oscillator 102 ... 1st drive circuit 103 ... 1st light source (light output means)
104 ... 180 ° phase shifter 105 ... second drive circuit 106 ... second light source (light output means)
107: Optical multiplexer (optical multiplexing means, light irradiation means)
108: Optical fiber (light irradiation means)
109 ... Sound wave detector (Sound wave detection means)
DESCRIPTION OF SYMBOLS 110 ... Amplifier 111 ... Waveform observation device 112 ... Recording and calculation apparatus (component concentration calculation means)
3 ... object to be measured S101-S105, S201-S208 ... step

Claims (8)

Light output means for outputting light of two different wavelengths, each of which is intensity-modulated by signals of opposite phase at the same frequency,
Optical multiplexing means for multiplexing the two lights;
A light irradiation means for irradiating the object to be measured with the combined light or only one light;
Sound wave detecting means for detecting sound waves generated inside the object to be measured by the irradiation;
Component concentration calculating means for calculating the concentration of the component to be measured in the object to be measured using a photoacoustic signal based on the magnitude of the detected sound wave,
The component concentration calculation means
A change in the normalization photoacoustic signal detected when the wavelength of the one light is swept in a predetermined wavelength range is obtained, and a ratio of the change in the normalization photoacoustic signal to the absorbance change in the wavelength range is determined. Calculate the absorbance of the measurement target component by dividing the photoacoustic signal detected when the combined light is irradiated by the ratio, and calculate the concentration of the measurement target component based on the absorbance A component concentration analyzer characterized by that. The component concentration calculation means
The component concentration analyzer according to claim 1, wherein the concentration of the measurement target component is further calculated using a change in absorbance of the measurement target component due to a temperature change. The component concentration calculation means
The frequency of the photoacoustic signal having the largest ratio is specified from a plurality of standardized photoacoustic signals detected when the frequency is varied, and the absorbance of the measurement target component obtained using the light of the frequency is determined. The component concentration analyzer according to claim 1, wherein the concentration of the measurement target component is calculated based on the component concentration analysis device. The component concentration calculation means
The component concentration analyzer according to any one of claims 1 to 3, wherein sweeping is performed in a wavelength range in which the absorbance change of the measurement target component in the measurement object is larger than the absorbance change of the measurement target component.   The two wavelengths are set such that the absorption exhibited by the component to be measured in the object to be measured is equal to each other, and one of the two wavelengths has the maximum absorption exhibited by the component to be measured. 5. The component concentration analyzer according to claim 1, wherein the component concentration analyzer is set to A light output step for outputting light of two different wavelengths, each of which is intensity-modulated by signals of opposite phases at the same frequency;
A light combining step for combining the two lights;
A light irradiation step of irradiating the object to be measured with the combined light or only one light; and
A sound wave detection step for detecting sound waves generated inside the object to be measured by the irradiation;
A component concentration calculating step for calculating a concentration of a measurement target component in the object to be measured using a photoacoustic signal based on the magnitude of the detected sound wave,
The component concentration calculating step includes:
A change in the normalization photoacoustic signal detected when the wavelength of the one light is swept in a predetermined wavelength range is obtained, and a ratio of the change in the normalization photoacoustic signal to the absorbance change in the wavelength range is determined. A calculating step;
Determining the absorbance of the measurement target component by dividing the photoacoustic signal detected when the combined light is irradiated by the ratio;
Calculating the concentration of the component to be measured based on the absorbance, and a component concentration analysis method. The component concentration calculating step includes:
The component concentration analysis method according to claim 6, wherein the concentration of the measurement target component is further calculated using the amount of change in absorbance of the measurement target component due to a temperature change. The component concentration calculating step includes:
The frequency of the photoacoustic signal having the largest ratio is specified from a plurality of standardized photoacoustic signals detected when the frequency is varied, and the absorbance of the measurement target component obtained using the light of the frequency is determined. 8. The component concentration analysis method according to claim 6, wherein the concentration of the measurement target component is calculated based on the component.

Images