JP2023080921A - Measuring method for hydrogen peroxide concentrations, and transistor type sensor for hydrogen peroxide detection and concentration measurement - Google Patents

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 The present invention relates to a method for measuring the concentration of hydrogen peroxide in water, and in particular hydrogen peroxide suitable for a method of measuring a low-concentration concentration of hydrogen peroxide contained in ultrapure water or the like using an organic transistor. It relates to a method for measuring concentration. The invention also relates to a transistor type sensor for hydrogen peroxide detection and concentration measurement.

Ultrapure water for cleaning, which is used in the semiconductor manufacturing process, is subjected to oxidation treatment of organic substances by ultraviolet rays in the ultrapure water manufacturing process. Hydrogen peroxide is produced as a by-product of the oxidation treatment of organic matter by ultraviolet rays. In order to maintain the purity of ultrapure water, it is necessary to control the concentration of hydrogen peroxide to be extremely low, and a technology for measuring extremely low concentrations of hydrogen peroxide in the ultrapure water production process is required.

Conventionally, coulometric titration with iodine has been used as a method for online measurement of hydrogen peroxide concentration, but the lower limit of determination is high (about 0.5 μg / L); a reagent is required for measurement; long measurement time (about 15 minutes); In addition, since reagents are used, replenishment is troublesome for on-site online measurements.

As an apparatus for measuring the concentration of hydrogen peroxide in water, there is one provided with means for decomposing hydrogen peroxide in water and means for measuring dissolved oxygen concentration before and after decomposition of hydrogen peroxide (Patent Documents 1 and 2).

JP 2012-63303 A Japanese Patent Application Laid-Open No. 2020-176868

The present invention provides a hydrogen peroxide concentration measuring method capable of easily and quickly measuring the hydrogen peroxide concentration without using reagents or hydrogen peroxide decomposition means, and a transistor type sensor for hydrogen peroxide detection and concentration measurement. The task is to provide

The gist of the present invention is as follows.

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

[2] The method for measuring hydrogen peroxide concentration of [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 phenylboronic acid compound is 4-mercaptophenylboronic acid. The method for measuring the hydrogen peroxide concentration of [1] or [2].

[4] The transistor type sensor has a transistor portion made of a field effect transistor and a detection portion separated 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 is brought into contact with water to be measured.

[5] A transistor-type sensor for hydrogen peroxide detection and concentration measurement having an extended gate incorporating a phenylboronic acid compound as a receptor.

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

[7] The transistor type sensor has a transistor portion made of a field effect transistor and a detection portion separated 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 hydrogen peroxide detection and concentration measurement 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.

The method for measuring hydrogen peroxide concentration and the transistor-type sensor for detecting and measuring hydrogen peroxide concentration of the present invention have a wide measurable concentration range (for example, 1 ng/L to 100 mg/L), require a small amount of sample water, and It has advantages such as no use of a micrometer and a short measurement time (30 seconds to 3 minutes, especially 1 to 5 minutes).

Further, in the hydrogen peroxide concentration measuring method and the hydrogen peroxide detection and concentration measuring transistor type sensor of the present invention, the sample water can be returned to the raw water tank of the pure water production system without additional treatment. be.

1 is a schematic longitudinal sectional view showing the configuration of a hydrogen peroxide concentration measuring device; FIG. 4 is a configuration diagram of a receptor portion; FIG. 1 is a chemical structure diagram of materials used in Examples. FIG. It is a graph showing the measurement result of an example. It is a graph showing the measurement result of an example. It is a graph showing the measurement result of an example. It is a graph showing the measurement result of an example. It is a graph showing the measurement result of an example. It is a graph showing the measurement result of an example.

In the present invention, a transistor-type sensor having an extended gate modified with a phenylboronic acid compound as a receptor is used, and water to be measured is brought into contact with the extended gate to measure the concentration of hydrogen peroxide in the water to be measured. The water to be measured is preferably pure water used in semiconductor manufacturing processes and the like, and its electric conductivity is preferably 1 mS/m or less.

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 and the like. In the present invention, a change in threshold voltage accompanying an increase in concentration of hydrogen peroxide is quantitatively read out by modifying an extended gate, which is a detection electrode obtained by partially extending the gate electrode, with a receptor.

In one aspect of the invention, a sensor chip for hydrogen peroxide uses phenylboronic acid compounds as artificial receptors. The phenylboronic acid compound binds to the extended gate gold electrode surface via a thiol group to modify the electrode surface, as shown in FIG. 2(a). The phenylboronic acid compound is oxidized by hydrogen peroxide and converted to a phenolic compound as shown in FIG. 2(b). Phenyl boronic acid compounds can be replaced with benzoxaborol. In addition, transistor-type artificial receptors may decompose if they contain heavy metal ions (Cu, Zn, Fe, etc.) exceeding 1000 mg/L or extreme acids such as piranha solution. preferably not.

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 them, a thin film transistor (TFT) made of an organic polymer is preferable because it is small and can be used easily.

1(a) and 1(b) show an example of the configuration of a transistor type sensor. A transistor-type sensor shown in FIG.

A transistor portion 10 is formed by forming a gate electrode 12 on a substrate 11 made of glass or the like, forming an AlOx film 13 on the surface thereof, and depositing tetradecylphosphonic acid (TDPA. The structural diagram is shown in FIG. 3B). A gate insulating film 14 made of is formed. Electrodes for a source 15 and a drain 16 are formed thereon.

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 them.

The detection site 20 , the extended gate, comprises a metal film 22 on a PEN substrate 21 . A thiolated phenylboronic acid compound is chemically bonded to the surface (upper surface in the drawing) of the metal film 22, as shown in FIG. 2(a). As the phenylboronic acid compound, 4-mercaptophenylboronic acid is suitable. The amount of 4-mercaptophenylboronic acid bound to the metal film surface is preferably about 1×10 ⁻⁹ to 1×10 ⁻⁸ mol/cm ² .

A channel material 23 made of synthetic resin is arranged on the metal film 22 . A portion of the channel hole S provided in the channel 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 channel hole S. As shown in FIG.

A wiring 30 electrically connects the metal film 22 and the gate electrode 12 .

When water to be measured containing hydrogen peroxide is passed through the channel hole S, the threshold voltage or drain current value of the transistor changes with the phenolization reaction of phenylboronic acid as shown in FIG. 2(b). By measuring the change in , the concentration of hydrogen peroxide in the water to be measured can be monitored.

In FIG. 1B, the channel material 23 is omitted. Other configurations in FIG. 1(b) are the same as those in FIG. 1(a), and the same reference numerals denote the same parts. In FIG. 1(b), the metal film 22 is brought into contact with water containing hydrogen peroxide, and the change in threshold voltage or drain current of the transistor is measured to measure the concentration of hydrogen peroxide in the water. do.

Materials constituting the transistor are not particularly limited. For example, by applying inorganic materials such as glass, ceramic glass, ceramics, and metals, as well as organic materials such as resins and papers, to the substrate, a flexible sensor can be constructed.

In the case of an organic transistor, for example, resins such as polyethylene naphthalate, polyethylene terephthalate, polyethylene, polyimide, and polyparaxylylene (parylene (registered trademark)), paper, and the like can be used as the substrate.

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

Materials constituting the gate insulating film include, for example, silica, alumina, self-assembled monolayer (SAM), polystyrene, polyvinylphenol, polyvinyl alcohol, polymethylmethacrylate, polydimethylsiloxane, polysilsesquioxane, ionic liquid, Polytetrafluoroethylene (Teflon (registered trademark) AF, Cytop (registered trademark)) and the like can be mentioned.

As a constituent material of the organic semiconductor, in the case of P-type, pentacene, dinaphthothienothiophene, benzothienobenzothiophene (Cn-BTBT), TIPS pentacene, TES-ADT, rubrene, P3HT, PBTTT, etc. can be used. In the case of N-type, fullerene or the like can be used. The structural formula of PBTTT is shown in FIG. 3(a).

Materials constituting the sealing film (protective film) include polytetrafluoroethylene (Teflon (registered trademark) AF), CYTOP (registered trademark), polyparaxylylene (parylene (registered trademark)), and the like. The structural formula of Cytop (registered trademark) is shown in FIG. 3(b).

Examples of the constituent material of the channel material include silicon resin and the like.

Thin film transistors can be produced by dry processes such as vapor deposition and sputtering, coating by spin coating, bar coating, spray coating, screen printing, gravure offset printing, letterpress reverse printing, and inkjet printing by various printing machines. good. Printing can be made more efficiently and at a lower cost.

In order to bind the phenylboronic acid compound to the metal film of the detection site 20, which is the extended gate, the metal film may be immersed in a phenylboronic acid compound solution, such as a methanol solution in which 4-mercaptophenylboronic acid is dissolved. The concentration of this solution is preferably about 1 to 10 mM, and the immersion time is preferably about 1 to 2 hours.

As shown in Fig. 1, the transistor portion and the extension gate, which is the detection portion, are fabricated separately, and by connecting them when in use, only the extension gate that is in direct contact with the sample can be easily replaced depending on the service life. can be installed. As a result, the transistor portion can be measured in a stable state. In addition, there is no need to replace the entire sensor, and the detection site can be used repeatedly by washing, so there is also the advantage of being economical.

In the present invention, it is preferable to measure the concentration of hydrogen peroxide in ultrapure water by immersing the transistor sensor in ultrapure water and reading the change in threshold voltage quantitatively.

Specifically, the transistor-type sensor is installed so that the entire electrode portion is immersed in the target water system. The place where the transistor-type sensor is installed is, but is not limited to, treated water from a UV treatment facility, water supply from a hydrogen peroxide decomposition facility, and further treated water from a hydrogen peroxide decomposition facility. In addition, the transistor type sensor may be installed directly in the above equipment or may be installed in a bypass line. In order to avoid this, it is preferable to pass water through the bypass line only during measurement. In addition, if it is difficult to install the transistor type sensor in the above equipment or if the transistor type sensor is severely worn, after sampling ultrapure water from the above equipment, the transistor type sensor can be immersed in the sampling water and measured. good.

The water to be measured is desirably measured at room temperature as much as possible. In the case of hot water, the consumption of the transistor-type sensor is accelerated. When the transistor type sensor is installed directly in the line or in a bypass line, a heat exchanger for cooling is separately installed so that the temperature of the water to be measured reaches room temperature as much as possible, or the line is made longer and the transistor type sensor is installed. The temperature of the water to be measured is preferably room temperature when contacting the sensor, but is not limited to this.

[Example 1]
<Experimental conditions>
Add 30% hydrogen peroxide (special grade) manufactured by Kishida Chemical Co., Ltd. to ultrapure water produced with a Milli-Q purification device (Millipore), , 1 μg/L, 500, 100, 50, 30, 10, 7.5, 5, 3, and 1 ng/L aqueous hydrogen peroxide solutions were prepared.

An extended gate type organic transistor (having the structure shown in FIG. 1(b)) was manufactured by introducing 4-mercaptophenylboronic acid as a 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 and immersing the metal film 22 in the solution for 1 hour. It was carried out by washing with methanol and ultrapure water.

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

Materials and thicknesses of main parts of the transistor are as follows.

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

<Results/Discussion>
The results are shown in Figures 4-7. As shown in FIGS. 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 FIGS. 4 _to 7 is a numerical value ₍ V _{th −V th0} )/V _th0 was used.

[Example 2]
<Experimental conditions>
As shown in FIG. 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 the channel material 23 was integrated with the extension gate. The channel material 23 was formed using polydimethylsiloxane (PDMS).

The area of the measuring part of the extension gate is 15 mm ² . The channel size of the channel hole S is 50 μm in height, 100 μm in width, and 6 mm in length at the portion in contact with the metal film.

The voltage _VGS between the gate electrode and the source electrode was -3.0V, and the voltage _VDS between the drain electrode and the source electrode was -1.0V.

Real-time measurement was performed by measuring the current I _DS flowing between the drain electrode and the source electrode when alternately flowing an aqueous hydrogen peroxide solution with a hydrogen peroxide concentration of 10 μg/L and ultrapure water at a flow rate of 46 μL/min. was tested for followability.

<Results/Discussion>
The results are shown in FIG. As shown in FIG. 8, when the hydrogen peroxide solution and the ultrapure water were flowed alternately, the _IDS value changed within 1 minute after changing the type of fluid, and then reached a steady state. From this, it was confirmed that this transistor could measure the concentration of hydrogen peroxide in real time with good followability.

[Example 3]
<Experimental conditions>
Using an extended gate type organic transistor introduced with 4-mercaptophenylboronic acid having 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 ion (NO ₃ ⁻ ), hypochlorite ion (ClO ⁻ )) adjusted to 100 ng/L. was measured.

The voltage V _th between the gate electrode and the source electrode was -3.0V, and the voltage V _th between the drain electrode and the source electrode was -1.0V.

<Results/Discussion>
The results are shown in FIG. As shown in FIG. 9, it was suggested that the transistor-type sensor is capable of specific detection of hydrogen peroxide. The threshold voltage on the y _- axis _in FIG. 9 is the numerical value (V _{th -V th0 )} / V _th0 was used.

REFERENCE SIGNS LIST 10 transistor portion 11 substrate 12 gate electrode 13 AlOx film 14 gate insulating film 15 source electrode 16 drain electrode 17 organic semiconductor layer 20 detection portion 21 substrate 22 metal film 23 channel material

Claims (7)

A method of measuring the concentration of hydrogen peroxide in water to be measured by contacting water to be measured with the extended gate using a transistor type sensor having an extended gate into which a phenylboronic acid compound is introduced as a receptor. 2. The method for measuring the concentration of hydrogen peroxide 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. The phenylboronic acid compound is 4-mercaptophenylboronic acid. 3. The method for measuring hydrogen peroxide concentration according to claim 1 or 2. The transistor type sensor has a transistor portion made of a field effect transistor and a detection portion separated 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,
4. The method for measuring the concentration of hydrogen peroxide according to claim 3, wherein the surface of the metal film having the phenylboronic acid compound is brought into contact with water to be measured. A transistor-type sensor for hydrogen peroxide detection and concentration measurement with an extended gate incorporating a phenylboronic acid compound as a receptor. 6. The transistor type sensor for hydrogen peroxide detection and concentration measurement according to claim 5, wherein said phenylboronic acid compound is 4-mercaptophenylboronic acid. The transistor type sensor has a transistor portion made of a field effect transistor and a detection portion separated 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,
7. The transistor-type sensor for hydrogen peroxide detection and concentration measurement according to claim 5 or 6, wherein the surface of said metal film having said phenylboronic acid compound is a surface to be brought into contact with water to be measured.

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