JPH0618421A - Solution ingredient sensor - Google Patents

Abstract

PURPOSE:To provide a solution ingredient sensor that can achieve its miniaturization by making respective elements such as an emission light source, a subject solution cell, a light receiving parts or the like integrally into one body. CONSTITUTION:This solution ingredient sensor is provided with a luminous element 2 exciting a porous semiconductor for emission, a subject solution passage 10 being installed so as to traverse an optical path out of this luminous element, and running a subject solution colored according to the concentration of a measuring objective ingredient, and a light receiving element 7 receiving a light out of the luminous element transmitted through the subject solution and converting it into an electric output. The luminous element 2, light receiving element 7 and subject solution passage 10 are integrated and formed in two semiconductor substrates 1 and 6 of one body or a laminated structure, and they are constituted so as to measure the concentration of the measuring objective ingredient by means of intensity of a light after being transmitted through the subject solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution component sensor for measuring the concentration of components in a solution.

[0002]

2. Description of the Related Art Absorption spectroscopy is mainly used in solution component measurement, particularly in instrumental analysis of various solution components represented by biochemical analysis. This absorption spectroscopy is a method in which a reagent that develops or develops a color by reacting with a component to be measured is added to a test liquid, and this color change is subjected to absorption spectroscopy to quantify the detection component. For example, in an automatic biochemical analyzer for blood or the like, absorption spectroscopy is applied to measure 30 or more kinds of components.

To explain the outline of the conventional analyzer using the absorption spectroscopy, white light from a halogen lamp or the like serving as a light source is guided to one end of the absorption cell by an optical fiber or the like. The light-absorbing cell contains a test liquid and a reagent that reacts with a component to be measured in the test liquid to generate an appropriate color or change in color.
The white light is absorbed according to the concentration of the measurement target component while passing through the light absorption cell and reaching the light receiving unit. The concentration of the component to be measured is measured by dispersing the absorbed light with a diffraction grating or the like and obtaining the absorbance at a wavelength where a desired absorption peak is generated with a photodiode array or the like.

In such a conventional absorption spectroscopic analyzer, the light introduction system from the light source to the cell, the light introduction system from the cell to the spectroscopic section, the spectroscopic section, the light receiving section, etc. are each constituted by independent parts. However, there is a problem that the entire apparatus is complicated and becomes large in size. In particular, it is difficult to integrate the light-emitting part because it is a halogen lamp, etc., and the spectroscopic part using the diffraction grating is difficult to miniaturize mechanically and requires precise processing precision, which results in downsizing of the device. It was a factor that hindered cost reduction.

Further, in the conventional absorption spectroscopy as described above, it is necessary to add a reagent for causing a color change at each measurement, and this reagent is consumed when a large number of analyzes are performed. This caused an increase in measurement cost.

On the other hand, in the automatic analyzer for various solution components, some electrolytes are measured by the ion electrode method.
This is generally based on a plastic such as vinyl chloride on the surface of an electrode such as platinum or silver, and an ion-sensitive material such as a macrocyclic ionophore such as valinomycin for potassium ions mixed with a plasticizer. The film is applied. Sensing is performed by utilizing the fact that the potential is selectively changed by specific target ions using such an electrode.

However, in the ion electrode method, since it is necessary to precisely measure the electric potential of the electrode having an extremely high impedance, it is extremely sensitive to the noises of the sensor and the wiring around the sensor and the amplifier, and the handling is complicated. At the same time, there is a drawback that the measurement accuracy is likely to decrease. Also,
Since only this system is a potential measuring type, not light, it is necessary to provide a separate system, which is a disadvantage when considering the size and simplification of the entire measuring system.

[0008]

As described above, the conventional absorption spectroscopy type solution component analyzer has a problem that the whole apparatus is complicated and becomes large in size, and is consumed for each measurement. There is a problem that the measurement cost is high depending on the reagent. On the other hand, in the ion electrode method, the potential is likely to become unstable and it is extremely sensitive to noise,
There is a problem that the handling is complicated and the measurement accuracy is likely to decrease.

The present invention has been made to address the above-mentioned problems of the prior art, and made it possible to integrally integrate a light emitting light source, a sample liquid introduction cell, and a light receiving portion. Its main purpose is to provide a small-sized solution component sensor. Furthermore, after avoiding the consumption of reagents,
It is an object of the present invention to provide a solution component sensor that solves the problems of the ion electrode type sensor, that is, the instability of the electric potential and the vulnerability to noise.

[0010]

A first solution component sensor according to the present invention is provided so as to cross a light emitting element that excites a porous semiconductor to emit light, and an optical path from the light emitting element. A test liquid flow path that circulates a test liquid that has been colored or developed in accordance with the concentration, and a light receiving element that receives light from the light emitting element that has passed through the test liquid and converts it into an electrical output Then, the light emitting element, the light receiving element and the test liquid flow path are integrally formed in a semiconductor substrate having an integrated or laminated structure, and the concentration of the measurement target component is determined by the intensity of light after passing through the test liquid. It is characterized by being configured to measure.

The second solution component sensor has a porous semiconductor provided facing the flow path of the test liquid, a means for exciting the porous semiconductor to emit light, and a light emission from the porous semiconductor. A light-receiving element for receiving and converting into an electrical output, and detecting at least one of the emission wavelength and intensity from the porous semiconductor that changes when contacting the test solution, and measuring in the test solution It is characterized by being configured to measure the concentration of the target component.

[0012]

In the solution component sensor of the present invention, a semiconductor ultrafine porous material such as silicon is used as a light emitting light source. By using such a porous semiconductor as a light source, it becomes possible to integrally form the respective elements such as the light emitting light source, the test liquid cell, the light receiving element, etc. on a substantially integrated substrate by the semiconductor fine processing technology. . This makes it possible to increase the accuracy of arrangement of each element and significantly reduce the size of the entire system. Further, it is possible to reduce the amount of test liquid required for measurement.
Furthermore, since it is possible to easily form a plurality of light emitting elements having different emission spectrum peaks in an array, by providing a plurality of light receiving elements corresponding to each of them, a compact spectroscope without a diffraction grating is provided. A measurement system can be realized.

When the semiconductor ultrafine porous body is irradiated with excitation light having energy higher than the bandgap or injected with electric charge, light emission according to the fine structure of the semiconductor is observed. Even in the case of an indirect transition type semiconductor such as silicon, when it is made porous by electrolytic etching or the like, a direct transition light emission phenomenon occurs, and the light emission characteristics change depending on the gas atmosphere to which the porous body is exposed. Then, the present inventors have found that this light emission phenomenon is observed even in a solution, and that it changes depending on the solution component. Therefore,
In the state where the porous semiconductor is in contact with the solution to be the test liquid,
By exciting the porous semiconductor with light or electric charges, it is possible to obtain light emission with an intensity or wavelength corresponding to the concentration of the component to be measured in the test liquid. By detecting the emission intensity and the emission wavelength, it is possible to measure the concentration of the measurement target component without consuming the reagent. Further, unlike the conventional potential detection type sensor, the measurement accuracy and the like do not deteriorate due to the disturbance noise. Also, the solution component sensor by this optical detection method can also be realized basically by processing the same semiconductor material, so that each functional part can be integrated and formed on a substantially integrated substrate. As a result, an optical component sensor which is significantly smaller than the conventional one can be realized.

[0014]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a sectional view showing the essential structure of an embodiment of a solution component sensor according to the present invention. In the figure,
Reference numeral 1 is a first semiconductor substrate made of a crystalline silicon substrate or the like. The first semiconductor substrate 1 is formed with a plurality of porous silicon layers 2a, 2b by electrolytic etching using, for example, a hydrofluoric acid-based etching solution. 2c and 2d are provided separately. The plurality of porous silicon layers 2 each function as a light emitting element and are formed so as to have different emission wavelengths.

For the porous silicon layer 2, an ohmic electrode is formed on the back surface of a crystalline silicon substrate, and this is used as an anode, and a platinum plate or the like is used as a counter electrode to perform electrolytic etching in a hydrofluoric acid-based etching solution. Can be formed by. As the etching liquid, for example, 49% hydrofluoric acid is used, but in order to improve the surface uniformity, a diluted solution of ethanol or the like can be used. It is also effective to irradiate light with a tungsten lamp or the like during etching in order to increase the porosity of the porous layer. Furthermore, it is also effective to increase the emission intensity by leaving it in hydrofluoric acid and performing post-etching after completion of electrolytic etching.

The light emission characteristics of the porous silicon layer 2 are
Since it varies depending on the etching conditions, this is used to change the emission characteristics (e.g. emission wavelength) from each porous silicon layer 2a, 2b, 2c, 2d. As a specific method of changing the light emission characteristics, impurities of different concentrations are diffused in advance in the porous layer forming portion, electrolytic etching is performed at different current densities, or light irradiation conditions during electrolytic etching are changed. It may be changed, or the immersion time of the post-etching in hydrofluoric acid after electrolytic etching may be changed.

In this embodiment, electrolytic etching is carried out in 49% hydrofluoric acid while changing the current density in the range of 20 to 80 mA / cm ² to thereby obtain a plurality of peak wavelengths in the range of 600 nm to 800 nm. Porous silicon layers 2a, 2b, 2
c, 2d were obtained.

On the surface of the first semiconductor substrate 1 on which the porous silicon layer 2 is formed, a transparent conductive layer 3 and a transparent insulating film 4 are formed in order, and the light emitting section 5 is formed by these. Is configured. As the transparent conductive layer 3, an ITO film or a gold ultra-thin film as a charge injection layer for the porous silicon layer 2 by a sputtering method or a band gap estimated from the emission wavelength of the porous silicon layer 2 is used. A semiconductor layer having a wide band gap, that is, a semiconductor layer of the opposite conductivity type forming a pn junction with the porous silicon layer 2 is exemplified. Then, by injecting a charge from the transparent conductive layer 3 into each porous silicon layer 2, or by energizing the pn junction formed by the transparent conductive layer 3 and each porous silicon layer 2, Each porous silicon layer 2a, 2b, 2c, 2d emits light at a wavelength according to each etching condition.

In this embodiment, an example in which charge injection by the transparent conductive layer 3 or pn junction of a semiconductor is used as the excitation and emission means of the porous silicon layer 2 has been described, but the porous semiconductor layer in the present invention is described. The excitation light emitting means is not limited to these, and for example, as in the examples described later, the porous semiconductor layer may be excited by light to emit light. A crystalline germanium substrate or the like can also be used as the first semiconductor substrate 1 forming the porous semiconductor layer.

On the other hand, each porous silicon layer 2 is formed on the second semiconductor substrate 6 which is a p-type silicon substrate on the light receiving side.
A plurality of n-type impurity layers 7a, 7b, 7c, 7d are provided at the same intervals so as to correspond to a, 2b, 2c, 2d, and a plurality of photodiodes functioning as light receiving elements are formed. Then, the transparent insulating film 8 is formed on these surfaces to form the light receiving portion 9.

The respective porous silicon layers 2 which are the light emitting elements and the respective photodiodes 7 which are the light receiving elements are arranged so as to face each other, and a space is provided between the first semiconductor substrate 1 and the second semiconductor substrate 6. By joining and integrating the first semiconductor substrate 1 which becomes the light emitting portion 5 and the second semiconductor substrate 6 which becomes the light receiving portion 9 so that the interval 10 which becomes the test liquid flow path and the light absorbing cell is formed, The solution component sensor 11 is configured.

That is, since the space 10 serving as the test liquid flow path and the light absorption cell is provided so as to cross the light emission optical path from the porous silicon layer 2, the light emitted from each porous silicon layer 2 is not emitted. After being partially absorbed by a solution (test solution) colored or developed by an appropriate reagent flowing through the test solution flow path 10, the intensity of each photodiode 7 is detected. The absorption of light changes depending on the concentration of the component (solute) to be measured in the solution that is the test solution, that is, the coloration or color development state of the reagent. Therefore, measure the intensity of light after passing through the test solution. Thus, the concentration of the measurement target component can be quantified.

Further, in the solution component sensor of the above embodiment, since the plurality of porous silicon layers 2 having different emission wavelengths are used as the light emitting element, the spectroscopic measurement can be performed without using the diffraction grating. it can.

Using the solution component sensor 11 of the above-described embodiment, a mixture of a serum sample and a coloring reagent is introduced into the test liquid flow path 10, and each light emitting element (porous silicon layer 2) is introduced. The intensity of the light after passing the test liquid by applying a voltage to emit light is measured by the corresponding photodiode 7
The concentration of inorganic phosphorus in the serum sample was measured. Specifically, first, add 5% trichloroacetic acid (TCA) to a 12 ml centrifuge tube.
9.50 ml of the above was taken, 0.500 ml of serum was added and mixed well, left for 5 minutes, and then centrifuged at 1500 rpm until the supernatant became clear. 5.00 ml of this supernatant was placed in a test tube, and 1 ml of ammonium molybdate solution was added and mixed well. Ammonium molybdate solution contains 2.5 g of ammonium molybdate
It was dissolved in 80 ml of water and 30 ml of 5M sulfuric acid was added to prepare the solution. After leaving this for 5 to 10 minutes, the test liquid flow path 1 of the sensor 11
It was introduced at 0 and the absorbance was measured. At the time of this measurement, a standard concentration phosphoric acid solution was prepared and a calibration curve was prepared. In addition,
The change in absorption in this case was measured near 650 nm. By doing so, the phosphate concentration in serum could be accurately measured.

FIG. 2 is a diagram showing an embodiment of a solution component sensor having a porous semiconductor layer whose emission peak wavelength is continuously changed. That is, in this example, p
^- After forming the first semiconductor substrate 12 on the insulating film 13 made of -type silicon substrate, (in the figure, the horizontal direction) flow direction of the test fluid is continuously changed structure porous silicon layer 14
Is formed. Such a porous silicon layer 14 is
For example, it can be obtained by irradiating white light with different illuminance in the left-right direction during anodic etching. Specifically, a filter whose transmittance changes continuously is arranged directly above the etching surface, and electrolytic etching is performed at a constant current density while irradiating a tungsten lamp on the filter. In addition, by arranging the back surface electrode during electrolysis at uneven positions in the left-right direction, changing the current density depending on the location, or changing the post-etching time depending on location, the porous structure can be made continuous. It is possible to obtain a porous semiconductor layer in which

A transparent conductive film 15 for charge injection and a spectral layer 16 are sequentially formed on the porous silicon layer 14 having the above-described structure which is continuously changed. The spectral layer 16 divides the surface of the porous silicon layer 14 (light emitting element) whose emission peak wavelength is continuously changed by continuously changing the structure, and divides the surface into the respective light receiving elements (described later) to be arranged facing each other. It is for guiding only light having a specific peak wavelength. Therefore, the light extraction windows 16a, 16
The light-splitting layer 16 has a certain thickness so that the light reaches only the light receiving element that is placed opposite from a. Then, the spectral layer 16 and the respective light extraction windows 16a, 1
The light emitting portion 18 is formed by covering 6a ... with a protective insulating film (transparent insulating film) 17.

On the other hand, on the second semiconductor substrate 19 made of p ^- type silicon substrate, a plurality of photodiodes to be light receiving elements are provided corresponding to the respective light extraction windows 16a, 16a. ⁺ Diffusion layers 20, 20 ... Are formed. Then, the light receiving portion 22 is configured by forming the transparent insulating film 21 on these surfaces and forming the photocurrent extraction electrodes (not shown) of the respective light receiving elements 19.

Then, the light extraction windows 16a, 16 ... A of the first semiconductor substrate 12 and the second semiconductor substrate 19 are formed.
Of the photodiodes 20 and 20 are opposed to each other, and the substrates 12 and 19 are bonded to each other so that a space 23 serving as a test liquid flow path and a light absorption cell is formed between the substrates 12 and 19. The solution component sensor 24 is configured by being integrated.

According to the solution component sensor 24 of the above embodiment, it is possible to easily form an array of light emitting elements having different emission peaks, and to realize a multi-wavelength spectroscopic element in a more compact manner. The solution component sensor 24 of this embodiment also
It is used in the same manner as the solution component sensor 11 of the above-mentioned embodiment.

In each of the above-described embodiments, an example is described in which the light emitting portion and the light receiving portion are formed on different semiconductor substrates and then these are joined and integrated. However, even in such a case, it is optically The light emitting element and the light receiving element need only be faced to each other in a one-to-one manner, and it is possible to assemble easily and accurately without the need to perform complicated optical path alignment as in the conventional spectral absorption apparatus. In addition, since the optical system is manufactured by applying the semiconductor integration technology, the entire system can be significantly downsized as compared with the conventional one, and thus the device can be downsized and simplified. further,
Since semiconductor integration technology is applied, it is also possible to form a large number of units on a substrate at the same time, combine the light emitting section and the light receiving section using these, and then divide the units.

Further, in the solution component sensor of the present invention, the light emitting portion, the test liquid flow path and the light receiving portion can be formed on one semiconductor substrate. Furthermore, the drive circuit of the light emitting part
It is also possible to integrally form the amplification of the output photocurrent and the arithmetic circuit.

By using a plurality of porous semiconductor layers having different emission wavelengths or a porous semiconductor layer whose emission wavelength changes continuously as in each of the above-mentioned embodiments,
Since it becomes possible to perform spectroscopic measurement, the range of measurement is expanded more effectively, but even when using a porous semiconductor layer of one wavelength, the solution component sensor of the present invention is effective and obtains that effect. You can

Next, examples of other solution component sensors according to the present invention will be described. FIG. 3 is a diagram showing a configuration of a main part of an embodiment of a solution component sensor that utilizes the fact that the emission characteristics (emission wavelength and emission intensity) from the porous semiconductor layer change depending on the components of the contacted solution.

In the figure, reference numeral 31 is a first semiconductor substrate made of a crystalline silicon substrate or the like, and the first semiconductor substrate 31 is provided with a porous silicon layer 32 by electrolytic etching similar to the above-mentioned embodiment. ing. The porous silicon layer 32 is excited by the light irradiation described later,
It emits light according to the concentration of the solution component. As described above, the light emission characteristics change depending on the etching conditions, and thus are set according to the measurement target, the required sensitivity, and the like. Typically, an ohmic electrode is formed on the back surface of a p ^- type silicon wafer having a specific resistance of about 10 Ωcm, and this is used as an anode, and a platinum plate is used as a counter electrode, and the current density is 20 to 80 m.
Etching is performed at A / cm ² for 1 to 5 minutes. Further, similarly to the above-mentioned examples, in order to improve the surface uniformity, a dilute solution with ethanol may be appropriately used, and in order to increase the porosity of the porous layer, a tungsten lamp or the like is used during etching. You may irradiate with light. Furthermore, it is also effective to increase the emission intensity by leaving it in hydrofluoric acid and performing post-etching after completion of electrolytic etching.

Further, the surface of the porous silicon layer 32 may be modified with a functional group having a thickness of about 10 nm or less in order to improve the selectivity for a specific detection component. Such functional groups include, for example, proton groups, hydroxyl groups, hydrocarbon groups including methyl groups, carboxyl groups, amino groups, azo groups, diazo groups, phenyl groups, vinyl groups, silanol groups, bis-crown ether groups, etc. Is used.

The first semiconductor substrate 31 is located on the light receiving portion side so that a space 33 serving as a test liquid flow path is formed.
It is joined and integrated with a second semiconductor substrate 34 made of a crystalline silicon substrate. The porous silicon layer 32 of the first semiconductor substrate 31 is arranged so as to come into contact with the test liquid in the test liquid flow path 33.

In the second semiconductor substrate 34, an n-type diffusion region is provided to form a photodiode 35 by a pn junction, and an opening portion provided at a position corresponding to the porous silicon layer 32. An excitation light introduction part 37 of the porous silicon layer 32 by an optical fiber or the like is installed inside the device 36. Further, an insulating film 38 that electrically insulates the photodiode 35, which serves as a light receiving element, from the solution is formed on the surface of the second semiconductor substrate 34 on the test liquid flow path 33 side. As the insulating film 38, a film having a filter characteristic for cutting off direct incidence of excitation light may be formed.

In the solution component sensor having the above-described structure, the emission wavelength and intensity from the porous silicon layer 32 change depending on the concentration of the measurement target component in the solution flowing in the test liquid flow path 33. The concentration of the component to be measured can be quantified by detecting the change in at least one of the above. When the test liquids having different pHs were sequentially introduced into the test liquid flow path 33 using the solution component sensor, the luminescence intensity captured by the photodiode 35 changed depending on the pH of the test liquid. It was confirmed that it could be detected.

FIG. 4 is a diagram showing a main part of a modified example of the solution component sensor. In the solution component sensor of this embodiment, in addition to the light emitting / receiving unit 39 for detecting the solution component,
A light emitting / receiving unit 40 for reference is provided. The reference light emitting / receiving unit 40 includes a light introducing unit 37 and a photodiode 35 serving as a light receiving element. By adopting such a configuration, it is possible to calibrate changes in the amount of received light due to factors such as the turbidity of the solution to be tested.

FIG. 5 is a diagram showing the essential structure of an embodiment of a solution component sensor to which charge injection is applied as an exciting means for the porous semiconductor layer. An insulating film 43 is provided on the first semiconductor substrate 42 having the porous silicon layer 41 formed in the same manner as in the above-described embodiment except the surface of the porous silicon layer 41. An electrode 44 for exciting the porous silicon layer 41 is provided on the insulating film 43. The excitation electrode 44 is preferably made of an inert metal such as platinum or gold. In addition, the excitation electrode 44
The installation place of is not limited to the above-mentioned place, and may be any place as long as it is in contact with the test liquid and is insulated from the porous silicon layer 41 and the light receiving element 45 described later.

In such a first semiconductor substrate 42, a photodiode serving as the light receiving element 45 and the transparent insulating film 47 are formed in the same manner as in the above-described embodiment, with a space serving as the test liquid flow path 46 secured. A solution component sensor is configured in combination with the second semiconductor substrate 48.

In the solution component sensor having the above structure, a solution to be a test solution is introduced into the test solution flow path 46, and charges are injected from the excitation electrode 44 into the porous silicon layer 41 through the test solution. By doing so, the porous silicon layer 41 is excited to emit light. Then, similarly to the above-described example, the concentration of the measurement target component can be quantitatively measured by detecting the emission wavelength and the intensity that change according to the concentration of the measurement target component in the solution. However, with this solution component sensor,
It is necessary to give conductivity to the test liquid, and in some cases the conductivity is adjusted by adding an irrelevant electrolyte to the test liquid. In the actual measurement, the calibration liquid is first introduced to measure the emission intensity, and then the target test liquid is introduced to detect the change in emission intensity.

It should be noted that each of the solution component sensors utilizing the change in the light emission characteristics from the porous semiconductor layer described above can be combined with the same absorption analysis as the solution component sensor of the above-mentioned embodiment.

[0045]

As described above, according to the solution component sensor of the present invention, each element such as the light emitting light source, the test liquid cell and the light receiving portion can be integrated and formed on a substantially integrated substrate. Become. As a result, the arrangement accuracy of the respective elements can be remarkably improved as compared with the prior art, and the entire system can be downsized, which in turn makes it possible to downsize and simplify the entire apparatus. Further, an optical detection type solution component sensor is provided in which the consumption of a reagent is avoided by utilizing the change of light emission characteristics from a porous semiconductor, and the weakness of the potential detection type sensor against disturbance noise is overcome. It becomes possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main configuration of a solution component sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a main part of a solution component sensor according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing the configuration of the main part of an embodiment of a solution component sensor that utilizes changes in light emission characteristics from a porous semiconductor according to the present invention.

FIG. 4 is a cross-sectional view showing a main configuration of a modification of the solution component sensor shown in FIG.

FIG. 5 is a cross-sectional view showing the configuration of the main part of another embodiment of a solution component sensor that utilizes changes in light emission characteristics from a porous semiconductor according to the present invention.

[Explanation of symbols]

 1, 12, 31, 42 ... First semiconductor substrate 2, 14, 32, 41 ... Porous silicon layer 3, 15 ... Translucent conductive layer 5, 18 ... Light emitting part 6, 19, 34, 48 ... Second semiconductor substrate 7, 20, 35, 45 ... Photodiode 9, 22 ... Light receiving part 10, 23, 33, 46 ... Test liquid flow path 11, 24 ... Solution component sensor 37 ... … Excitation light introduction part 44 …… Excitation electrode

Claims (2)

[Claims] 1. A light-emitting element that excites a porous semiconductor to emit light, and a test solution that is provided so as to cross an optical path from the light-emitting element and that is colored or developed in accordance with the concentration of a component to be measured is circulated. And a light receiving element that receives light from the light emitting element that has passed through the test liquid and converts the light into an electrical output. The light emitting element, the light receiving element, and the test liquid flow path are provided. A solution component sensor, characterized in that it is formed integrally on a semiconductor substrate having an integral or laminated structure, and that the concentration of the component to be measured is measured by the intensity of light after passing through the test liquid. 2. A porous semiconductor provided facing a flow path of a test liquid, and means for exciting and emitting the porous semiconductor,
A light-receiving element that receives light emitted from the porous semiconductor and converts it into an electrical output, and detects at least one of the emission wavelength and the intensity of the light emitted from the porous semiconductor, which changes when the light-emitting element contacts the test liquid. A solution component sensor, which is configured to measure the concentration of a measurement target component in the test liquid.