Method for measuring hydrogen peroxide concentration and transistor-type sensor for detecting and measuring hydrogen peroxide concentration

Abstract

To provide a measuring method for hydrogen peroxide concentrations, capable of easily and quickly measuring hydrogen peroxide concentrations without using a reagent or hydrogen peroxide decomposition means.SOLUTION: A transistor type sensor having an extension gate obtained by introducing a phenylboronic acid compound as a receptor is used to bring water to be measured into contact with the extension gate to measure hydrogen peroxide concentrations in the water to be measured. The transistor type sensor includes a transistor part composed of a field effect transistor, and a detection part spaced from the transistor part. The detection part includes a metal film, and the phenylboronic acid compound bonded to a surface of the metal film. The metal film and a gate electrode of the field effect transistor are electrically connected by wiring with each other, and the water to be measured is brought into contact with the surface of the metal film having the phenylboronic acid compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for measuring the concentration of hydrogen peroxide in water, and in particular to a method for measuring the concentration of hydrogen peroxide at low concentrations in ultrapure water, etc., using an organic transistor.The present invention also relates to a transistor-type sensor for detecting and measuring hydrogen peroxide concentration. [Background technology]

[0002] Ultrapure water for cleaning used in semiconductor manufacturing processes is produced by oxidizing organic matter with ultraviolet light during the ultrapure water production process. Hydrogen peroxide is produced as a by-product of the ultraviolet oxidation of organic matter. To maintain the purity of ultrapure water, it is necessary to control the concentration of hydrogen peroxide to an extremely low level, which necessitates a technology to measure extremely low concentrations of hydrogen peroxide during the ultrapure water production process.

[0003] The conventional method for measuring hydrogen peroxide concentration online is coulometric titration using iodine, but this method has some issues, such as a high lower limit of quantification (approximately 0.5 μg / L), the need for reagents for measurement, the generation of waste liquid, and a long measurement time (approximately 15 minutes).In addition, because it uses reagents, it requires the effort of refilling them for on-site online measurement.

[0004] There is an apparatus for measuring the concentration of hydrogen peroxide in water that includes a means for decomposing hydrogen peroxide in water and a means for measuring the dissolved oxygen concentration before and after the decomposition of hydrogen peroxide (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-63303 [Patent Document 2] Japanese Patent Application Publication No. 2020-176868 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a method for measuring hydrogen peroxide concentration that can easily and quickly measure hydrogen peroxide concentration without using reagents or hydrogen peroxide decomposition means, and a transistor-type sensor for detecting and measuring hydrogen peroxide concentration. [Means for solving the problem]

[0007] The gist of the present invention is as follows.

[0008] [1] A method for measuring the concentration of hydrogen peroxide in water to be measured by using a transistor sensor with an extended gate to which a phenylboronic acid compound is introduced as a receptor, and bringing the water to be measured into contact with the extended gate.

[0009] [2] The method for measuring the concentration of hydrogen peroxide according to [1], wherein the concentration of hydrogen peroxide in the water to be measured is in the range of 1 ng / L to 100 mg / L.

[0010] [3] The method for measuring a hydrogen peroxide concentration according to [1] or [2], wherein the phenylboronic acid compound is 4-mercaptophenylboronic acid.

[0011] [4] The transistor-type sensor has a transistor portion made of a field-effect transistor and a detection portion spaced apart from the transistor portion, the detection site has a metal film and the phenylboronic acid compound bound to the surface of the metal film; the metal film and the gate electrode of the field effect transistor are electrically connected by wiring, The method for measuring the concentration of hydrogen peroxide according to [3], wherein the surface of the metal film having the phenylboronic acid compound thereon is brought into contact with the water to be measured.

[0012] [5] A transistor-type sensor with an extended gate incorporating a phenylboronic acid compound as a receptor for detecting and measuring hydrogen peroxide concentration.

[0013] [6] The transistor-type sensor for detecting and measuring the concentration of hydrogen peroxide according to [5], wherein the phenylboronic acid compound is 4-mercaptophenylboronic acid.

[0014] [7] The transistor-type sensor has a transistor portion made of a field-effect transistor and a detection portion spaced apart from the transistor portion, the detection site has a metal film and the phenylboronic acid compound bound to the surface of the metal film; the metal film and the gate electrode of the field effect transistor are electrically connected by wiring, The transistor-type sensor for detecting and measuring the concentration of hydrogen peroxide according to [5] or [6], wherein the surface of the metal film having the phenylboronic acid compound is the surface that comes into contact with the water to be measured. [Effects of the Invention]

[0015] The method for measuring hydrogen peroxide concentration and the transistor-type sensor for detecting and measuring hydrogen peroxide concentration of the present invention have advantages such as a wide measurable concentration range (e.g., 1 ng / L to 100 mg / L), a small amount of sample water required, no reagents required, and a short measurement time (30 seconds to 3 minutes, particularly about 1 to 5 minutes).

[0016] Furthermore, the method for measuring hydrogen peroxide concentration and the transistor-type sensor for detecting and measuring hydrogen peroxide concentration of the present invention allow the sample water to be returned to the raw water tank of the pure water production system without any additional treatment. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic vertical cross-sectional view showing the configuration of a hydrogen peroxide concentration measuring device. [Figure 2] FIG. 2 is a structural diagram of a receptor portion. [Figure 3] FIG. 1 is a diagram showing the chemical structures of materials used in the examples. [Figure 4] 10 is a graph showing the measurement results of an example. [Figure 5]10 is a graph showing the measurement results of an example. [Figure 6] 10 is a graph showing the measurement results of an example. [Figure 7] 10 is a graph showing the measurement results of an example. [Figure 8] 10 is a graph showing the measurement results of an example. [Figure 9] 10 is a graph showing the measurement results of an example. DETAILED DESCRIPTION OF THE INVENTION

[0018] In the present invention, a transistor-type sensor having an extended gate modified with a phenylboronic acid compound as a receptor is used, and the concentration of hydrogen peroxide in the sample water is measured by bringing the sample water into contact with the extended gate. The sample water is preferably pure water used in semiconductor manufacturing processes, and its electrical conductivity is preferably 1 mS / m or less.

[0019] An organic thin-film transistor is composed of a substrate, a gate electrode, a gate insulating film, a source electrode, a drain electrode, an organic semiconductor, a sealing film, etc. In the present invention, a receptor is modified on an extension gate, which serves as a detection electrode by partially extending the gate electrode, and the change in threshold voltage associated with an increase in the concentration of hydrogen peroxide can be quantitatively read out.

[0020] In one embodiment of the present invention, a hydrogen peroxide sensor chip uses a phenylboronic acid compound as an artificial receptor. The phenylboronic acid compound binds to the surface of an extended-gate gold electrode via a thiol group, as shown in Figure 2(a), modifying the electrode surface. The phenylboronic acid compound is oxidized by hydrogen peroxide and converted to a phenolic compound, as shown in Figure 2(b). The phenylboronic acid compound can be replaced with benzoxaborole. Furthermore, because transistor-type artificial receptors can decompose in the presence of heavy metal ions (e.g., Cu, Zn, Fe) exceeding 1000 mg / L or extreme acids such as piranha solution, it is preferable that they not be present in the solution to be measured.

[0021] The transistor portion of the transistor-type sensor used in the present invention can be configured with a known transistor structure, and may be an inorganic transistor or an organic transistor. Among these, a thin-film transistor (TFT) made of an organic polymer is preferred because it is small and easy to use.

[0022] 1(a) and (b) show an example of the configuration of a transistor-type sensor. The transistor-type sensor shown in Fig. 1(a) is composed of a transistor portion 10 and an extension gate which is a detection portion 20.

[0023] The transistor portion 10 has a gate electrode 12 formed on a substrate 11 made of glass or the like, an AlOx film 13 formed on the surface thereof, and a gate insulating film 14 made of tetradecylphosphonic acid (TDPA; the structure is shown in FIG. 3(b)). Source 15 and drain 16 electrodes are formed thereon.

[0024] An organic polymer semiconductor layer 17 is formed between the source electrode 15 and the drain electrode 16. A sealing film 18 is formed to seal these.

[0025] The extension gate, which is the detection site 20, comprises a metal film 22 on a PEN substrate 21. As shown in FIG. 2(a), a thiolated phenylboronic acid compound is chemically bonded to the surface (top surface of the figure) of the metal film 22. 4-mercaptophenylboronic acid is a suitable phenylboronic acid compound. The amount of 4-mercaptophenylboronic acid bonded to the metal film surface is 1×10 -9 ~1×10 -8 mol / cm 2 Process degree is preferred.

[0026] A flow path material 23 made of synthetic resin is disposed on the metal film 22. A part of a flow path hole S formed in the flow path material 23 is exposed on the upper surface of the metal film 22. A reference electrode 24 made of an Ag / AgCl electrode is provided so as to be inserted into the flow path hole S.

[0027] The metal film 22 and the gate electrode 12 are electrically connected by a wiring 30 .

[0028] When the test water containing hydrogen peroxide is passed through this flow path hole S, the concentration of hydrogen peroxide in the test water can be monitored by measuring the change in the threshold voltage or drain current value of the transistor, which changes with the reaction of phenylboronic acid to phenol, as shown in Figure 2(b).

[0029] In Figure 1(b), the flow path material 23 is omitted. The other configuration of Figure 1(b) is the same as Figure 1(a), and the same reference numerals indicate the same parts. In Figure 1(b), the hydrogen peroxide concentration in the measurement water is measured by bringing the measurement water containing hydrogen peroxide into contact with the metal film 22 and measuring the change in the threshold voltage or drain current value of the transistor.

[0030] The material for forming the transistor is not particularly limited. For example, the substrate may be made of inorganic materials such as glass, ceramic glass, ceramics, and metal, or organic materials such as resin and paper, to form a flexible sensor.

[0031] In the case of an organic transistor, the substrate may be made of, for example, a resin such as polyethylene naphthalate, polyethylene terephthalate, polyethylene, polyimide, or polyparaxylylene (Parylene (registered trademark)), or paper.

[0032] Examples of materials for the gate electrode include aluminum, silver, gold, copper, titanium, indium tin oxide (ITO), and PEDOT:PSS, and examples of materials for the source and drain electrodes include gold, silver, copper, platinum, aluminum, and conductive polymers such as PEDOT:PSS.

[0033] Examples of materials that can be used for the gate insulating film include silica, alumina, self-assembled monolayers (SAMs), polystyrene, polyvinylphenol, polyvinyl alcohol, polymethyl methacrylate, polydimethylsiloxane, polysilsesquioxane, ionic liquids, and polytetrafluoroethylene (Teflon (registered trademark) AF, Cytop (registered trademark)).

[0034] As constituent materials of organic semiconductors, for P-type, pentacene, dinaphthothienothiophene, benzothienobenzothiophene (Cn-BTBT), TIPS pentacene, TES-ADT, rubrene, P3HT, PBTTT, etc. can be used, and for N-type, fullerene, etc. can be used. The structural formula of PBTTT is shown in Figure 3(a).

[0035] Examples of materials that can be used to form the sealing film (protective film) include polytetrafluoroethylene (Teflon (registered trademark) AF), Cytop (registered trademark), polyparaxylylene (Parylene (registered trademark), etc. The structural formula of Cytop (registered trademark) is shown in Figure 3(b).

[0036] Examples of the constituent material of the flow path material include silicone resin.

[0037] The method for manufacturing a thin film transistor may be a dry process such as vapor deposition or sputtering, or may be coating such as spin coating, bar coating, or spray coating, or printing using various printing machines such as screen printing, gravure offset printing, letterpress reverse printing, or inkjet printing. Printing allows for more efficient and low-cost manufacturing.

[0038] To bind a phenylboronic acid compound to the metal film of the detection site 20 (extension gate), the metal film can be immersed in a phenylboronic acid compound solution, such as a methanol solution containing 4-mercaptophenylboronic acid. The concentration of this solution is preferably about 1 to 10 mM, and the immersion time is preferably about 1 to 2 hours.

[0039] As shown in Figure 1, the transistor section and the extension gate, which is the detection section, are fabricated separately and connected when in use. This allows for easy replacement and installation of only the extension gate, which comes into direct contact with the sample, depending on its lifespan. This allows the transistor section to perform measurements in a stable state. Furthermore, there is no need to replace the entire sensor, and the detection section can be reused by simply cleaning it, making it economical.

[0040] In the present invention, it is preferable to immerse the transistor sensor in ultrapure water and quantitatively read the change in threshold voltage to measure the concentration of hydrogen peroxide in the ultrapure water.

[0041] Specifically, the transistor-type sensor is installed so that the entire electrode portion is immersed in the target water system. The location where the transistor-type sensor is installed includes, but is not limited to, treated water from a UV treatment facility, water supply to a hydrogen peroxide decomposition facility, or treated water from a hydrogen peroxide decomposition facility. The transistor-type sensor may be installed directly in the facility or in a bypass line. However, installation in the bypass line is preferred to avoid wear on the transistor-type sensor. Furthermore, to avoid wear, it is preferable to pass water through the bypass line only during measurement. If installation in the facility is difficult or wear on the transistor-type sensor is excessive, ultrapure water may be sampled from the facility, and the transistor-type sensor may be immersed in the sampled water for measurement.

[0042] It is desirable to measure the water to be measured at room temperature as much as possible. High-temperature water will cause rapid wear of the transistor-type sensor. When the transistor-type sensor is installed directly in the line or in a bypass line, it is preferable to install a separate heat exchanger for cooling so that the temperature of the water to be measured is as close to room temperature as possible, or to make the line longer so that the temperature of the water to be measured is room temperature when it comes into contact with the transistor-type sensor, but this is not limitative. [Example]

[0043] [Example 1] <Experimental conditions> 30% hydrogen peroxide (special grade) manufactured by Kishida Chemical was added to ultrapure water produced using a Milli-Q purification apparatus (Millipore) to prepare aqueous hydrogen peroxide solutions with concentrations of 100, 50, 10, 5, and 1 mg / L, 100, 50, 10, 5, and 1 μg / L, and 500, 100, 50, 30, 10, 7.5, 5, 3, and 1 ng / L.

[0044] An extended-gate organic transistor (configuration shown in Figure 1(b)) was fabricated in which 4-mercaptophenylboronic acid was introduced as the phenylboronic acid compound. The phenylboronic acid compound (4-mercaptophenylboronic acid) was introduced into the metal film 22 by dissolving 4-mercaptophenylboronic acid in methanol to a concentration of 10 mM, immersing the metal film 22 in the solution for 1 hour, and then washing with methanol and ultrapure water.

[0045] The detection portion 20 of this transistor was immersed in each of the above solutions, and the threshold voltage was measured after 5 minutes.

[0046] The materials and thicknesses of the main parts of the transistor are as follows:

[0047] Gate electrode: Aluminum, 30 nm Source and drain: gold, 30 nm Organic semiconductor: PBTTT Sealing film: Cytop (registered trademark) Metal film: gold, thickness 100 nm, area 15 mm 2 Source-drain spacing: 50 μm

[0048] <Results / Discussion> The results are shown in Figures 4 to 7. As shown in Figures 4 to 7, a good correlation was obtained between the hydrogen peroxide concentration and the threshold voltage. The threshold voltage on the y-axis in Figures 4 to 7 represents the threshold voltage (V th ) and blank threshold voltage (V th0 ) is V th0 The value divided by (V th-V th0 ) / V th0 was used.

[0049] [Example 2] <Experimental conditions> 1(a), the concentration of hydrogen peroxide was measured in real time using an organic transistor having the same configuration as in Example 1, except that a channel material 23 was integrated into the extension gate. The channel material 23 was formed using polydimethylsiloxane (PDMS).

[0050] The area of ​​the extension gate measurement section is 15 mm 2 The channel size of the channel hole S is 50 μm in height, 100 μm in width, and the length of the part in contact with the metal film is 6 mm.

[0051] Voltage between gate electrode and source electrode V GS is -3.0V, and the voltage between the drain and source electrodes V DS was set to -1.0V.

[0052] The current I flowing between the drain and source electrodes when an aqueous solution of hydrogen peroxide adjusted to a hydrogen peroxide concentration of 10 μg / L and ultrapure water were alternately flowed at a flow rate of 46 μL / min. DS The tracking ability of real-time measurements was tested by measuring the

[0053] <Results / Discussion> The results are shown in Figure 8. As shown in Figure 8, when hydrogen peroxide solution and ultrapure water were flowed alternately, I DS The value of t changed and then reached a steady state. This demonstrates that this transistor can measure the concentration of hydrogen peroxide in real time with good response.

[0054] [Example 3] <Experimental conditions> Using an extended-gate organic transistor incorporating 4-mercaptophenylboronic acid with the same configuration as in Example 1, hydrogen peroxide and peroxides (benzoyl peroxide (BPO), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), tert-butyl hydroperoxide (t-BHP), nitrate ions (NO3 - ), hypochlorite ion (ClO - Measurements were carried out on an aqueous solution adjusted to 100 ng / L.

[0055] Voltage between gate electrode and source electrode V th is -3.0V, and the voltage between the drain and source electrodes V th was set to -1.0V.

[0056] <Results / Discussion> The results are shown in Figure 9. As shown in Figure 9, it was suggested that the transistor-type sensor is capable of specifically detecting hydrogen peroxide. The threshold voltage on the y-axis of Figure 9 represents the threshold voltage (V th ) and blank threshold voltage (V th0 ) is V th0 The value divided by (V th -V th0 ) / V th0 was used. [Explanation of symbols]

[0057] 10 Transistor part 11 Circuit Board 12 gate electrode 13 AlOx film 14 Gate insulating film 15 Source electrode 16 Drain electrode 17 Organic semiconductor layer 20 Detection site 21 PCB 22 Metal Film 23 Channel material

Claims

1. A method for measuring the concentration of hydrogen peroxide in water to be measured by using a transistor-type sensor having a detection site made of an extension gate into which a phenylboronic acid compound is introduced as a receptor, the method comprising bringing the water to be measured into contact with the extension gate, the detection site has a metal film, the phenylboronic acid compound bound to a surface of the metal film, and a water channel hole provided so that a portion of the water channel hole is exposed to the surface of the metal film; the phenylboronic acid compound is 4-mercaptophenylboronic acid, A method for measuring the concentration of hydrogen peroxide by passing the water to be measured through the water channel hole.

2. 2. The method for measuring a hydrogen peroxide concentration according to claim 1, wherein the concentration of hydrogen peroxide in the water to be measured is in the range of 1 ng / L to 100 mg / L.

3. the transistor-type sensor has a transistor portion made of a field-effect transistor and the detection portion spaced apart from the transistor portion, the metal film and the gate electrode of the field effect transistor are electrically connected by wiring, 3. The method for measuring the concentration of hydrogen peroxide according to claim 2, wherein a flow path material made of synthetic resin is disposed on the metal film, and the water channel holes are provided in the flow path material.

4. A transistor-type sensor for detecting and measuring the concentration of hydrogen peroxide, which has a detection site consisting of an extended gate into which a phenylboronic acid compound is introduced as a receptor, the detection site has a metal film, the phenylboronic acid compound bound to a surface of the metal film, and a water channel hole provided so that a portion of the water channel hole is exposed to the surface of the metal film; the phenylboronic acid compound is 4-mercaptophenylboronic acid, A transistor-type sensor for detecting and measuring the concentration of hydrogen peroxide, in which the water to be measured is passed through the water channel hole.

5. the transistor-type sensor has a transistor portion made of a field-effect transistor and the detection portion spaced apart from the transistor portion, the metal film and the gate electrode of the field effect transistor are electrically connected by wiring, 5. A transistor-type sensor for detecting and measuring the concentration of hydrogen peroxide according to claim 4, wherein a flow path material made of synthetic resin is disposed on the metal film, and the water channel holes are provided in the flow path material.

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