JPH05119012A - Cell for electrochemical measurement - Google Patents

Abstract

PURPOSE:To obtain a measurement cell which is used for a measuring device which can perform electrochemical detection and can especially perform a stable and accurate measurement. CONSTITUTION:A cell for electrochemical measurement is provided with two electrodes, namely an operation electrode 2 and an opposite electrode 3, or three electrodes, namely the operation electrode 2. a reference electrode 4, and the opposite electrode 3. A gap for retaining a measurement sample is provided between a bottom surface 1 of a measurement cell and an upper surface 6 of the measurement cell which opposes it nearly in parallel. A distance between the bottom surface 1 of the measurement cell and the upper surface 6 of the measurement cell is set to a range where a measurement sample liquid solution can be retained by an interface tension and the sample liquid solution can be retained stably.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、電気化学検出を行う測
定装置に用いられる測定用セルに関し、特に正確な測定
が行える電気化学測定用セルに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring cell used in a measuring device for electrochemical detection, and more particularly to an electrochemical measuring cell capable of performing accurate measurement.

【０００２】[0002]

【従来の技術】分析化学の分野において電気化学検出は
下記のような利点によって広く用いられている。即ち、
一般には測定困難な化学量を、電気量に直接変換して
測定するために測定が容易に行える。ファラデーの法
則に従って進行する電気化学反応を観察するために、電
流値や電気量から微量な物質変化を捉えることができ高
感度の測定が行える。反応の過程を即時に知ることが
でき、迅速な検出・定量が可能である。そして、ポテン
シオメトリー、アンペロメトリー、ポーラログラフィ
ー、クーロメトリー、インピーダンス測定、サイクリッ
クボルタンメトリー等の方法で各種物質の測定に応用さ
れている。特に近年、酵素・微生物・抗原・抗体等やそ
れらの固定化素子と組み合わせてバイオセンサーを構築
する等、その応用範囲が広がっている。2. Description of the Related Art Electrochemical detection is widely used in the field of analytical chemistry with the following advantages. That is,
In general, a chemical quantity that is difficult to measure is directly converted into an electric quantity for measurement, which facilitates the measurement. In order to observe the electrochemical reaction that proceeds according to Faraday's law, it is possible to capture a minute amount of substance change from the current value or the amount of electricity, and perform highly sensitive measurement. The reaction process can be immediately known, and rapid detection / quantification is possible. It is applied to the measurement of various substances by methods such as potentiometry, amperometry, polarography, coulometry, impedance measurement, and cyclic voltammetry. In particular, in recent years, the range of applications has expanded, such as the construction of biosensors by combining enzymes, microorganisms, antigens, antibodies, etc., or their immobilization elements.

【０００３】このように数々の利点を備えた優れた測定
方法ではあるが、実際に電気化学測定を応用した装置を
構成する場合に、信頼性のある測定値を得るためには、
電気化学測定の測定条件を一定になるように制御する必
要がある。つまり、電気化学検出は種々の要因に左右さ
れるので、測定条件を一定にする必要上、装置構成が複
雑となる問題があった。Although this is an excellent measurement method having various advantages as described above, in order to obtain a reliable measurement value when actually constructing an apparatus to which electrochemical measurement is applied,
It is necessary to control the measurement conditions of the electrochemical measurement so as to be constant. That is, since electrochemical detection depends on various factors, there is a problem that the device configuration becomes complicated because it is necessary to keep the measurement conditions constant.

【０００４】例えばその重要な因子として、作用電極表
面への被測定物質の供給状態の一様性が挙げられる。通
常よく用いられるアンペロメトリーを例にとれば、参照
電極に対して一定の電位を加えられた作用電極に供給さ
れる被測定物質の供給速度を一定に保つことが重要な条
件となる。このためにバッチ方式と連続流れ方式の２つ
に大別される測定装置において、バッチ方式の測定装置
ではいかに再現性・安定性よく被測定物質を含んだ試料
溶液を攪拌するか、また連続流れ方式の測定装置ではい
かに再現性・安定性よく試料または移動相を送液するか
が大きな問題となる。For example, an important factor is the uniformity of the supply state of the substance to be measured on the surface of the working electrode. Taking amperometry, which is commonly used, as an example, it is an important condition to maintain a constant supply rate of the substance to be measured supplied to the working electrode to which a constant potential is applied to the reference electrode. For this reason, in a measuring device that is roughly divided into a batch method and a continuous flow method, how well the sample solution containing the substance to be measured is agitated with good reproducibility and stability in the batch method, and the continuous flow The major problem in the measurement system of the method is how to reproducibly and stably deliver the sample or the mobile phase.

【０００５】バッチ方式においては正確に溶液を攪拌す
ることが要求されるために回転を正確に制御する装置が
必要となり測定装置が複雑化する要因となっている。こ
れに対して従来より簡単に作用電極に供給される被測定
物質の供給速度を一定に保つ機構が種々検討されてき
た。例えば回転ディスク電極は溶液を回転子で攪拌する
場合に比較して作用電極表面への対流による被測定物質
の供給速度を一定に保ち易く広く利用されている。しか
し装置構成の複雑さに関しては溶液を回転子で攪拌する
かわりに作用電極を回転させるために依然として回転装
置とその制御装置が必要であった。In the batch method, since it is required to accurately stir the solution, a device for accurately controlling the rotation is required, which is a factor of complicating the measuring device. On the other hand, various mechanisms have been studied in which the supply speed of the substance to be measured supplied to the working electrode can be kept constant more easily than in the past. For example, a rotating disk electrode is widely used because it is easy to maintain a constant supply rate of a substance to be measured by convection on the surface of a working electrode as compared with a case where a solution is stirred by a rotor. However, with respect to the complexity of the device configuration, a rotating device and its control device were still required to rotate the working electrode instead of stirring the solution with a rotor.

【０００６】一方溶液を攪拌したり、移動相を送液した
りせずに測定する電気化学検出法としてサイクリックボ
ルタンメトリー、ポーラログラフィー等がある。本来静
止した試料溶液に対して定電圧を印加すると、Ｃｏｔｔ
ｒｅｌｌの式に従った電解電流が流れるはずである。こ
れは被測定物質の拡散に基づいた電流であり電流値は電
位を印加してからの時間ｔの平方根の逆数に比例して減
少していく。しかし、実際には静止しているはずの試料
溶液の微小な対流などのゆらぎ・測定開始時の電極界面
の乱れ等により拡散層内に被測定物質が供給されたり、
また拡散層内の被測定物質の濃度勾配が乱されたりする
ために良好な測定精度を得るのは困難であった。On the other hand, there are cyclic voltammetry, polarography and the like as electrochemical detection methods for measuring without stirring the solution or feeding the mobile phase. When a constant voltage is applied to the originally stationary sample solution, Cott
An electrolytic current according to the Rell equation should flow. This is a current based on the diffusion of the substance to be measured, and the current value decreases in proportion to the reciprocal of the square root of the time t after applying the potential. However, the substance to be measured is supplied into the diffusion layer due to fluctuations such as minute convection of the sample solution that should be actually stationary, disturbance of the electrode interface at the start of measurement, etc.
Further, it is difficult to obtain good measurement accuracy because the concentration gradient of the substance to be measured in the diffusion layer is disturbed.

【０００７】これらの問題点に関して従来いくつかの提
案がなされてきた。例えば特開昭６１−２１３６６３号
では電極部の全面に均一に被測定試料溶液が保持される
ように電極部の上に保水層を設ける方法が開示されてい
る。しかしこのように保水層を設ける方法では被測定試
料溶液と大気との気液界面の物理的な微動に起因するば
らつきに対しては有効ではないためか、応答電流値のば
らつきは大きく、精度の良い測定は困難であった。Several proposals have been made in the past with respect to these problems. For example, Japanese Patent Application Laid-Open No. 61-213663 discloses a method of providing a water retention layer on the electrode portion so that the sample solution to be measured is uniformly held on the entire surface of the electrode portion. However, this method of providing the water retention layer is not effective for the variation caused by the physical fine movement of the gas-liquid interface between the sample solution to be measured and the atmosphere. Good measurements were difficult.

【０００８】また、従来より提案されている他の方法で
も充分に実用的な精度は得られていない。例えば、溶液
を正確に攪拌する装置や作用電極を正確に回転させる機
構、また試料溶液や移動相を正確に送液する機構が必要
であり測定セルもそれらの機構の併用を前提としたもの
が提案された。このため装置の複雑化は避け難く、本来
簡便かつ高精度を確保できる電気化学測定法の利点を活
かすものとはいえなかった。Further, other methods proposed hitherto have not yet achieved sufficiently practical accuracy. For example, a device that accurately stirs the solution, a mechanism that accurately rotates the working electrode, and a mechanism that accurately feeds the sample solution and mobile phase are required, and the measurement cell is premised on the combined use of these mechanisms. was suggested. For this reason, complication of the device is unavoidable, and it cannot be said that the advantage of the electrochemical measurement method, which is inherently simple and ensures high accuracy, can be utilized.

【０００９】[0009]

【発明が解決しようとする課題】本発明は、上記の問題
を解決し、特に簡便な構造により正確で安定な測定が行
える電気化学測定用セルを提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide an electrochemical measuring cell capable of accurate and stable measurement with a particularly simple structure.

【００１０】[0010]

【課題を解決するための手段】本発明は、作用電極・対
極の２電極、または作用電極・参照電極・対極の３電極
を有する電気化学測定用セルであり、測定セル底面と略
平行に対向する測定セル上面との間に被測定試料溶液を
保持する空隙を有し、測定セル底面と測定セル上面との
距離が被測定試料溶液を界面張力で保持できる範囲であ
る電気化学測定用セルである。The present invention is an electrochemical measurement cell having two electrodes of a working electrode and a counter electrode, or three electrodes of a working electrode, a reference electrode and a counter electrode, which face each other in substantially parallel to the bottom surface of the measurement cell. A cell for electrochemical measurement having a gap between the upper surface of the measurement cell to hold the sample solution to be measured, and the distance between the bottom surface of the measurement cell and the upper surface of the measurement cell is a range capable of holding the sample solution to be measured by interfacial tension. is there.

【００１１】また本発明は、測定セル底面と測定セル上
面との距離が０．１〜５ｍｍである上記の電気化学測定
用セルである。尚、測定セル底面及び測定セル上面は、
必ずしも前者が下になり、後者が上になる必要はない。
上、下、横等にしてもかまわない。説明上、底面、上面
と記載したに過ぎない。The present invention is also the above electrochemical measurement cell in which the distance between the measurement cell bottom surface and the measurement cell top surface is 0.1 to 5 mm. The bottom surface and the top surface of the measurement cell are
The former does not necessarily have to be on the bottom and the latter on the top.
It can be up, down, horizontal, etc. For the sake of explanation, it is simply described as the bottom surface and the top surface.

【００１２】[0012]

【作用】理論的には静止した被測定試料溶液中に保持さ
れた電極系に一定の電位を印加すれば、被測定物質の溶
液中での拡散のみに基づく電流が流れる。この電流値は
Ｃｏｔｒｅｌｌの式（１）であらわされる。 ｉ＝ｎＦＤＣ×１×（πＤｔ）^-1/2 （１） ただし各記号は以下の意味を持つ。Theoretically, when a constant potential is applied to the electrode system held in the stationary sample solution to be measured, a current flows only based on the diffusion of the material to be measured in the solution. This current value is expressed by Cotrol's equation (1). i = nFDC × 1 × (πDt) ^−1/2 (1) However, each symbol has the following meaning.

【００１３】ｎ：電極反応の電子数 Ｆ：ファラデー定数 Ｄ：被測定物質の拡散定数 Ｃ：被測定物質の濃度 ｔ：電圧印加後の経過時間 しかし、実際の測定では、電極表面の活性化状態、ある
いは被測定試料溶液の緩やかな対流、被測定試料溶液と
電極表面の固液界面の乱れ、大気と被測定試料溶液との
気液界面で発生する被測定試料溶液の微小な動きなどが
原因となり理論式からはずれた電流値変化が観察され
る。N: Electron number of electrode reaction F: Faraday constant D: Diffusion constant of substance to be measured C: Concentration of substance to be measured t: Elapsed time after application of voltage However, in actual measurement, activation state of electrode surface Or due to gradual convection of the sample solution to be measured, disturbance of the solid-liquid interface between the sample solution to be measured and the electrode surface, and minute movements of the sample solution to be measured that occur at the gas-liquid interface between the atmosphere and the sample solution to be measured. Then, a change in current value deviating from the theoretical formula is observed.

【００１４】この現象の原因は大きく分類すると （Ａ）作用電極の表面状態の変化に起因する現象 （Ｂ）作用電極と被測定試料溶液との固液界面に形成さ
れる拡散層の乱れに起因する現象の２つに大別されると
考えられる。 特に、静止しているはずの被測定試料溶液のわずかな対
流によって拡散層内に物質が供給されたり、大気の動き
や測定装置の微振動などにより大気と被測定試料溶液の
気液界面で発生する波動によって起こる拡散層の乱れは
特に偶発的であり測定値の再現性に好ましい結果を与え
ない。The causes of this phenomenon are roughly classified into (A) a phenomenon caused by a change in the surface state of the working electrode, and (B) a phenomenon caused by the disturbance of the diffusion layer formed at the solid-liquid interface between the working electrode and the sample solution to be measured. It is considered that there are two major phenomena. In particular, a substance is supplied into the diffusion layer due to slight convection of the sample solution to be measured that should be stationary, or it is generated at the gas-liquid interface between the atmosphere and the sample solution to be measured due to movement of the atmosphere or slight vibration of the measuring device. The disturbance of the diffusion layer caused by the generated waves is especially accidental and does not give a favorable result to the reproducibility of the measured values.

【００１５】そこで本発明は、測定セル底面と平行に対
向する測定セル上面との間に空隙を設け、その距離を短
くすることにより、被測定試料溶液の界面張力で、セル
中に安定的に保持されるように構成した。一般に、電気
化学検出法において再現精度の良好な測定を行うために
は測定条件を同一に保つことが重要な要素となる。Therefore, according to the present invention, a gap is provided between the bottom surface of the measurement cell and the top surface of the measurement cell, which is parallel to and opposed to the bottom surface of the measurement cell. Configured to be retained. Generally, in the electrochemical detection method, it is an important factor to keep the same measurement conditions in order to perform measurement with good reproducibility.

【００１６】この場合、空隙の距離は小さすぎると試料
溶液導入の際に気泡が形成され易くその気泡が電極表面
に接触すれば実質的な電極面積の減少を引き起こし電流
値の低下を引き起こす。また気泡が電極表面に接触して
いなくても電極の近傍に存在すれば、気液界面が電極の
近傍に存在することになり作用電極の拡散層の乱れを生
じさせやすい。逆に空隙の距離が大きすぎると被測定試
料溶液の保持が不安定になったり、対流の影響が大きく
なり再現性の低下を招く。従って空隙の距離は０．１〜
５ｍｍ程度であることが望ましい。より好ましくは０．
１〜１．５ｍｍ程度である。In this case, if the distance of the void is too small, bubbles are likely to be formed at the time of introducing the sample solution, and if the bubbles come into contact with the electrode surface, the electrode area is substantially reduced and the current value is lowered. If the bubbles are present near the electrode even if they are not in contact with the surface of the electrode, the gas-liquid interface is present near the electrode, and the diffusion layer of the working electrode is likely to be disturbed. On the other hand, if the distance of the void is too large, the retention of the sample solution to be measured becomes unstable, and the influence of convection becomes large, resulting in a decrease in reproducibility. Therefore, the distance of the void is 0.1
It is preferably about 5 mm. More preferably 0.
It is about 1 to 1.5 mm.

【００１７】セル壁面の開口部は各々セル底面、セル上
面、セル側壁の任意の場所に設けることができる。開口
部は１ケ所でも良い。開口部は、例えば測定セル底面と
測定セル上面とそれぞれ接する側壁部に形成することが
出来、セルの両端に１ケ所ずつ形成すると、試料溶液を
注入するときに効率よく空気が出るため便利である。こ
のように構成されたセルの壁面に被測定試料溶液をセル
内部に導入するための開口部と、被測定試料溶液によっ
て押し出される空気の逃げ口のための開口部を設けるこ
とが好ましい。試料注入口、空気抜け口、洗浄用開口部
の３ケ所の開口部を作っても良いし、自動的に注入、洗
浄等を行っても良い。また試料溶液の注入方法は１つの
開口部よりスポイトで注入したり、又はセルの１つの開
口部を試料溶液に接し、毛管現象によりセル中に導入す
ることもできる。The openings on the cell wall surface can be provided at arbitrary locations on the cell bottom surface, cell top surface, and cell side wall. There may be one opening. The openings can be formed, for example, in the side wall portions that are in contact with the measurement cell bottom surface and the measurement cell upper surface, respectively, and it is convenient to form one opening at each end of the cell because air can be efficiently ejected when the sample solution is injected. .. It is preferable to provide an opening for introducing the sample solution to be measured into the cell and an opening for an escape port for the air pushed out by the sample solution to be measured, on the wall surface of the cell configured as described above. The sample injection port, the air vent port, and the opening for cleaning may be formed in three places, or injection and cleaning may be automatically performed. As a method of injecting the sample solution, it is possible to inject the sample solution with a dropper from one opening, or one cell can be introduced into the cell by capillarity by bringing one opening into contact with the sample solution.

【００１８】セルの素材はアクリル、フッ素樹脂、塩化
ビニル、ガラスなどの非導電性素材、またステンレス、
金、白金などの導電性素材あるいはこれらを組み合せた
ものを用いることができる。導電性素材を使用する場合
は、電極系との電気的絶縁処理を行っておく等の注意を
要する。また例えばセル上面を取り外せるように構成す
ると、試料液を洗浄して取り替える場合に便利である。The material of the cell is acrylic, fluororesin, vinyl chloride, non-conductive material such as glass, stainless steel,
A conductive material such as gold or platinum or a combination thereof can be used. When using a conductive material, care must be taken such as electrical insulation treatment with the electrode system. Further, for example, if the upper surface of the cell is configured to be removable, it is convenient when cleaning and replacing the sample solution.

【００１９】電極系としては作用電極・対極より構成さ
れる２電極系、または作用電極・参照電極・対極より構
成される３電極系を例示することが出来る。電極は、例
えば測定セル底面中に導電性物質を埋め込んだり、内壁
表面に金属を蒸着する方法、溶液メッキ法、無電解メッ
キ法、印刷等の方法で形成することができる。各電極は
それぞれ上面や他の壁面に設けることもできる（図７参
照）。対極と参照電極の位置はそれぞれ作用電極と必ず
しも同一面上に配置する必要性はないが、電気化学計測
一般の通則に従って溶液間抵抗の影響を小さく抑えるた
めに、作用電極の近傍に配置することが望ましい。Examples of the electrode system include a two-electrode system composed of a working electrode and a counter electrode, or a three-electrode system composed of a working electrode, a reference electrode and a counter electrode. The electrodes can be formed by, for example, embedding a conductive substance in the bottom surface of the measurement cell or depositing a metal on the inner wall surface, a solution plating method, an electroless plating method, or a printing method. Each electrode can be provided on the upper surface or another wall surface (see FIG. 7). The positions of the counter electrode and the reference electrode do not necessarily have to be placed on the same plane as the working electrode, but they should be placed in the vicinity of the working electrode in order to keep the influence of the resistance between the solutions small according to the general rule of electrochemical measurement. Is desirable.

【００２０】作用電極には金、白金、銀などの金属電極
あるいはグラッシーカーボン、カーボンペーストなど通
常電気化学計測で用いられる素材であれば特に材質を選
ばない。対極には作用電極ですでに例示した材質または
ステンレスなどの導電性素材を用いることができ、ステ
ンレスなどの導電性素材を用いて構成したセルの接液部
を対極とすることもできる。The working electrode is not particularly limited as long as it is a metal electrode such as gold, platinum, silver or the like, or glassy carbon, carbon paste or the like which is a material usually used in electrochemical measurement. For the counter electrode, the material already exemplified for the working electrode or a conductive material such as stainless steel can be used, and the liquid contact portion of the cell configured using a conductive material such as stainless steel can also be the counter electrode.

【００２１】参照電極には銀・塩化銀参照電極、飽和カ
ロメル参照電極など一般的なものを例示することができ
る。本発明では試料導入口よりセル内に導入された試料
溶液は、セル底面とセル上面との間に溶液自体の界面張
力により安定に保持され、正確な測定が可能となる。As the reference electrode, general ones such as a silver / silver chloride reference electrode and a saturated calomel reference electrode can be exemplified. In the present invention, the sample solution introduced into the cell from the sample introduction port is stably held by the interfacial tension of the solution itself between the cell bottom surface and the cell top surface, and accurate measurement becomes possible.

【００２２】必要ならばセル内部の空隙の一部あるいは
全部に吸水体を充填し試料溶液の導入と保持の補助とす
ることもできる。またさらに必要ならば、その吸水体の
全体または一部に電気化学計測に必要とされる試薬類、
例えば緩衝液粉末、支持電解質、触媒や酵素等を含浸ま
たは固定化しておくこともできる。勿論作用極に酵素を
固定化することもできる。電気化学的検出は、酸素電
極、過酸化水素電極でそれぞれ酸素の減少や過酸化水素
の増加をアンペロメトリックに測定したり、或いは電極
活性物質をクーロメトリックに検出することも出来る。
酵素としてはグルコースオキシダーゼ、アルコールオキ
シダーゼ、乳酸オキシダーゼ、ガラクトースオキシダー
ゼ等のオキシダーゼや乳酸デヒドロゲナーゼ、グルタミ
ン酸デヒドロゲナーゼ等の脱水素酵素、或いはオキシゲ
ナーゼ等が例示できる。If necessary, some or all of the voids inside the cell may be filled with a water absorbing material to assist the introduction and retention of the sample solution. In addition, if necessary, all or a part of the water-absorbent reagent necessary for electrochemical measurement,
For example, a buffer solution powder, a supporting electrolyte, a catalyst, an enzyme and the like can be impregnated or immobilized. Of course, the enzyme can be immobilized on the working electrode. Electrochemical detection can also be performed by amperometrically measuring the decrease of oxygen and the increase of hydrogen peroxide at the oxygen electrode and the hydrogen peroxide electrode, or by coulometrically detecting the electrode active substance.
Examples of the enzyme include oxidases such as glucose oxidase, alcohol oxidase, lactate oxidase, galactose oxidase, dehydrogenases such as lactate dehydrogenase and glutamate dehydrogenase, and oxygenases.

【００２３】このような構成の電気化学測定用セルにお
ける再現性向上の理由については、下記のように考えら
れる。同一の３電極系を用いてただ電極系の表面上に被
測定試料溶液を展開した場合と、本発明のセルを用いた
測定を行った場合を比較すると、本発明では被測定試料
溶液の微小な振動を抑止した効果が大きいためと推察で
きる。本発明で開示された電気化学測定用セルを適当な
検出装置、検出回路に接続し試料導入のための機構を持
った装置に組み込むことにより、簡便な電気化学計測装
置を構成することができる。The reason why the reproducibility is improved in the electrochemical measurement cell having such a configuration is considered as follows. Comparing the case where the sample solution to be measured is simply spread on the surface of the electrode system using the same three-electrode system and the case where the measurement is performed using the cell of the present invention, in the present invention, It can be inferred that the effect of suppressing such vibrations is great. By connecting the electrochemical measurement cell disclosed in the present invention to an appropriate detection device and detection circuit and incorporating it into a device having a mechanism for introducing a sample, a simple electrochemical measurement device can be constructed.

【００２４】[0024]

【実施例】以下に実施例を挙げて、本発明の内容をさら
に詳細に説明するが、もちろん本発明はこれらに限定さ
れるものではない。 実施例１ 市販ポテンシオスタット装置（ＨＥＣＳ１１００型：扶
桑製作所製）に本発明の電気化学計測用測定セルを接続
し測定を行った（図８）。 （１）電気化学測定用セルの作成方法 図１にセルの斜視図を、図２にセルの構成部材の斜視図
を示す。EXAMPLES The contents of the present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. Example 1 A commercially available potentiostat device (HECS1100 type: manufactured by Fuso Seisakusho Co., Ltd.) was connected to the electrochemical measurement cell of the present invention for measurement (FIG. 8). (1) Method for producing cell for electrochemical measurement FIG. 1 shows a perspective view of the cell, and FIG. 2 shows a perspective view of constituent members of the cell.

【００２５】３０ｍｍ×３０ｍｍ、厚み３ｍｍのアクリ
ル製のセル底面（１）に直径２ｍｍの白金線の作用極
（２）と直径２ｍｍの白金線の対極（３）を２本、同じ
く直径２ｍｍの銀線１本を端面がアクリル製セル底面と
同一になるように略直線状に配置し埋め込んでエポキシ
樹脂でシールした。銀線の端面は０．１Ｍ塩酸水溶液
中、対飽和カロメル参照電極０．２５０Ｖの電位で３０
分電解し、塩化銀を析出させて銀・塩化銀参照電極
（４）とした。略直線状にならんだ電極と略並行になる
ように幅１０ｍｍ、長さ３０ｍｍ、厚み１ｍｍのフッ素
樹脂製のシート材（５）をスペーサーとして設置し、そ
の上に３０ｍｍ×３０ｍｍ、厚み３ｍｍのアクリル板を
セル上面（６）として取り付けた。セルの側面にできた
開口部の１つを試料導入口（７）、他方をセル内の空気
の逃し口（８）として用いた。 （２）測定方法 測定用セルを電極面が上向きにして、水平になるように
保持し、５０ｍＭ塩化カリウムを含む１００ｍＭリン酸
緩衝液に溶解した１０ｍＭ過酸化水素をスポイトで測定
用セル内部に充填し、対銀・塩化銀参照電極（４）＋
０．６Ｖの電圧を白金作用電極（２）に印加し、得られ
る電解電流値をレコーダーにて記録した。内部の過酸化
水素溶液を排除後、繰り返して測定を１０回行った。 （３）結果 得られたチャートより電圧印加後０〜２９．５秒まで
０．５秒おきに測定し、１０回の測定値の平均値（実
線）と標準偏差（破線）を図示すると図３のようになっ
た。測定の再現性を評価するために０〜２９．５秒まで
の各時間における１０回の測定の電流値の平均変動率
（ＣＶ％）を計算すると図４のようになった。平均変動
率は最小１．４％、最大５．６％、平均２．１％であっ
た。 比較例１ （１）電気化学測定用セルの作成方法 実施例１の電気化学測定用セルからアクリル製のセル上
面（６）およびフッ素樹脂製のシート材（５）を除いた
形のセルを作成した。A working electrode (2) of a platinum wire having a diameter of 2 mm and two counter electrodes (3) of a platinum wire having a diameter of 2 mm, and a silver electrode having a diameter of 2 mm, are formed on the bottom surface (1) of an acrylic cell having a size of 30 mm × 30 mm and a thickness of 3 mm. One line was arranged in a substantially straight line so that the end face was the same as the bottom face of the acrylic cell, embedded, and sealed with an epoxy resin. The end surface of the silver wire is 30 in a 0.1M hydrochloric acid aqueous solution at a potential of 0.250 V against a saturated calomel reference electrode.
Electrolysis was carried out separately, and silver chloride was deposited to obtain a silver / silver chloride reference electrode (4). A fluororesin sheet material (5) having a width of 10 mm, a length of 30 mm, and a thickness of 1 mm is installed as a spacer so as to be substantially parallel to the electrodes arranged in a substantially linear shape, and 30 mm × 30 mm, a thickness of 3 mm of acrylic is placed on the spacer. The plate was mounted as the cell top (6). One of the openings formed on the side surface of the cell was used as a sample introduction port (7), and the other was used as an air escape port (8) in the cell. (2) Measurement method Hold the measurement cell in a horizontal position with the electrode surface facing upward, and fill the measurement cell with 10 mM hydrogen peroxide dissolved in 100 mM phosphate buffer containing 50 mM potassium chloride with a dropper. And silver / silver chloride reference electrode (4) +
A voltage of 0.6 V was applied to the platinum working electrode (2), and the obtained electrolytic current value was recorded by a recorder. After removing the hydrogen peroxide solution inside, the measurement was repeated 10 times. (3) Results From the chart obtained, measurement is performed every 0.5 seconds from 0 to 29.5 seconds after voltage application, and the average value (solid line) and standard deviation (dashed line) of the measured values of 10 times are shown in FIG. It became like. In order to evaluate the reproducibility of the measurement, the average fluctuation rate (CV%) of the current value of 10 times of measurement in each time from 0 to 29.5 seconds was calculated, and the result is as shown in FIG. The average fluctuation rate was 1.4% at the minimum, 5.6% at the maximum, and 2.1% at the average. Comparative Example 1 (1) Method for producing electrochemical measurement cell A cell having a shape obtained by removing the acrylic cell upper surface (6) and the fluororesin sheet material (5) from the electrochemical measurement cell of Example 1 was produced. did.

【００２６】すなわち、３０ｍｍ×３０ｍｍ、厚み３ｍ
ｍのアクリル製セル底面に直径２ｍｍの白金線を２本、
同じく直径２ｍｍの銀線１本を端面がアクリル製セル底
面と同一平面上になるように略直線状に配置し埋め込ん
でエポキシ樹脂でシールした。銀線の端面は０．１Ｍ塩
酸水溶液中、対飽和カロメル参照電極０．２５０Ｖの電
位で３０分電解し、塩化銀を析出させ、銀・塩化銀参照
電極とした。 （２）測定方法 測定用セルを電極面が上向きに水平になるように保持
し、５０ｍＭ塩化カリウムを含む１００ｍＭリン酸緩衝
液に溶解した１０ｍＭ過酸化水素を、３電極系を被服す
るようにスポイトで滴下し、対銀・塩化銀参照電極０．
６Ｖの電位を白金作用電極に印加し、得られる電解電流
値をレコーダーにて記録した。この測定を１０回行っ
た。 （３）結果 得られたチャートより電圧印加後０〜２９．５秒までの
測定値を０．５秒おきに１０回の測定値の平均値（実
線）と標準偏差（破線）を図示すると図５のようになっ
た。測定の再現性を評価するために０〜２９．５秒まで
の各時間における１０回の測定の電流値の平均変動率
（ＣＶ％）を計算すると図６のようになった。平均変動
率は最小３．９％、最大６．８％、平均５．０％であっ
た。That is, 30 mm × 30 mm, thickness 3 m
2 platinum wires with a diameter of 2 mm on the bottom of the acrylic cell
Similarly, one silver wire having a diameter of 2 mm was arranged and embedded in a substantially straight line so that the end face was on the same plane as the bottom face of the acrylic cell, and was embedded and sealed with an epoxy resin. The end face of the silver wire was electrolyzed in a 0.1 M hydrochloric acid aqueous solution at a potential of 0.250 V against a saturated calomel reference electrode for 30 minutes to deposit silver chloride, thereby forming a silver / silver chloride reference electrode. (2) Measuring method A measuring cell is held with the electrode surface facing upward, and a 10 mM hydrogen peroxide solution dissolved in 100 mM phosphate buffer containing 50 mM potassium chloride is used as a dropper to cover the three-electrode system. , And a reference electrode for silver / silver chloride 0.
A potential of 6 V was applied to the platinum working electrode, and the resulting electrolytic current value was recorded with a recorder. This measurement was performed 10 times. (3) Results From the chart obtained, the measured values from 0 to 29.5 seconds after voltage application are shown every 0.5 seconds as the average value (solid line) and standard deviation (broken line) of 10 times. It became like 5. In order to evaluate the reproducibility of the measurement, the average fluctuation rate (CV%) of the current value of 10 times of measurement in each time from 0 to 29.5 seconds was calculated, and the result is as shown in FIG. The average variation rate was a minimum of 3.9%, a maximum of 6.8%, and an average of 5.0%.

【００２７】比較例１と実施例１を比べて、セル上部に
対向するアクリル板を配置した実施例１の結果が優れる
ことは明瞭である。 実施例２ （１）電気化学測定用セルの作成方法 フッ素樹脂製のシート材（５）を厚み１ｍｍではなく、
０．５ｍｍとした以外は、実施例１の測定セルと同じ物
を作成して用いた。 （２）測定方法 測定用セルを電極面が水平になるように保持し、スポイ
トで５０ｍＭ塩化カリウムを含む１００ｍＭリン酸緩衝
液に溶解した１０ｍＭ過酸化水素を測定用セル内部に充
填し、対銀・塩化銀参照電極０．６Ｖの電位を白金作用
電極に印加し、得られる電解電流値をレコーダーにて記
録した。この測定を１０回行った。 （３）結果 得られたチャートより電圧印加後０〜２９．５秒までの
測定値を０．５秒おきに記録した。１０回の測定の電流
値の平均変動率（ＣＶ％）を計算した。平均変動率は最
小１．３％、最大４．６％、平均２．０％で良好な測定
が可能であった。この結果は、対向する板の間隔が０．
５ｍｍであっても精度良い測定ができることを示してい
る。 比較例２ （１）電気化学測定用セルの作成方法 比較例１と同様のセルを用いた。 （２）測定方法 測定用セルを電極面が上向きに水平になるように保持
し、３電極系の上に保水層として幅１０ｍｍ、長さ３０
ｍｍ、厚み０．２２ｍｍのろ紙層を設け、５０ｍＭ塩化
カリウムを含む１００ｍＭリン酸緩衝液に溶解した１０
ｍＭ過酸化水素をスポイトで滴下し、対銀・塩化銀参照
電極＋０．６Ｖの電圧を白金作用電極に印加し、得られ
る電解電流値をレコーダーにて記録した。この測定を１
０回行った。 （３）結果 得られたチャートより電圧印加後０〜２９．５秒までの
測定値を０．５秒おきに記録した。測定の再現性を評価
するために０〜２９．５秒までの各時間における１０回
の測定の電流値の平均変動率（ＣＶ％）を計算した。最
小４．５％、最大９．６％、平均７．２％であった。実
施例１および実施例２が比較例２に比べて精度良く測定
できることは明瞭である。この結果より、電極上に保水
層を設けるよりも、作用電極表面を含む測定セル底面と
それに平行に対向する上面を設ける本発明の測定の方が
測定精度の向上をもたらすことがわかる。Comparing Comparative Example 1 and Example 1, it is clear that the result of Example 1 in which an acrylic plate facing the cell is arranged is excellent. Example 2 (1) Method for producing electrochemical measurement cell A fluororesin sheet material (5) was used, instead of having a thickness of 1 mm.
The same thing as the measuring cell of Example 1 was created and used except having set it as 0.5 mm. (2) Measurement method Hold the measurement cell so that the electrode surface is horizontal, and fill the inside of the measurement cell with 10 mM hydrogen peroxide dissolved in 100 mM phosphate buffer containing 50 mM potassium chloride with a dropper to prevent silver. -A potential of 0.6 V of the silver chloride reference electrode was applied to the platinum working electrode, and the obtained electrolytic current value was recorded by a recorder. This measurement was performed 10 times. (3) Results From the obtained chart, measured values from 0 to 29.5 seconds after voltage application were recorded every 0.5 seconds. The average variation rate (CV%) of the current value of 10 measurements was calculated. The average fluctuation rate was 1.3% at the minimum, 4.6% at the maximum, and 2.0% on the average, and good measurement was possible. This result shows that the distance between the opposing plates is 0.
It shows that accurate measurement can be performed even when the distance is 5 mm. Comparative Example 2 (1) Method for producing cell for electrochemical measurement The same cell as in Comparative Example 1 was used. (2) Measurement method The measurement cell was held so that the electrode surface was horizontal upward, and a width of 10 mm and a length of 30 as a water-retaining layer on the three-electrode system.
mm, 0.22 mm thick filter paper layer was prepared and dissolved in 100 mM phosphate buffer containing 50 mM potassium chloride 10
mM hydrogen peroxide was added dropwise with a dropper, a voltage of +0.6 V against silver / silver chloride reference electrode was applied to the platinum working electrode, and the obtained electrolytic current value was recorded by a recorder. This measurement is 1
I went 0 times. (3) Results From the obtained chart, measured values from 0 to 29.5 seconds after voltage application were recorded every 0.5 seconds. In order to evaluate the reproducibility of the measurement, the average fluctuation rate (CV%) of the current value of 10 measurements at each time from 0 to 29.5 seconds was calculated. The minimum was 4.5%, the maximum was 9.6%, and the average was 7.2%. It is clear that Example 1 and Example 2 can be measured more accurately than Comparative Example 2. From this result, it is understood that the measurement of the present invention in which the bottom surface of the measuring cell including the surface of the working electrode and the upper surface facing in parallel to the measurement cell are provided more improves the measurement accuracy than the water retention layer is provided on the electrode.

【００２８】[0028]

【発明の効果】本発明により簡単なセル構造で再現性の
良好な電気化学測定が可能となり、正確な電気化学計測
装置を構成することが可能となった。EFFECT OF THE INVENTION The present invention enables electrochemical measurement with a simple cell structure and good reproducibility, and makes it possible to construct an accurate electrochemical measuring device.

【図面の簡単な説明】[Brief description of drawings]

【図１】図１は本発明の電気化学測定用セルの１例を示
した斜視図である。FIG. 1 is a perspective view showing an example of an electrochemical measurement cell of the present invention.

【図２】図２は本発明の電気化学測定用セルの１例を示
した構成部材の斜視図である。FIG. 2 is a perspective view of constituent members showing an example of the electrochemical measurement cell of the present invention.

【図３】図３は実施例１の結果を示したものである。横
軸は電位印加後の経過時間（秒）、縦軸は電流値（μ
Ａ）である。電位印加後の０〜２９．５秒まで０．５秒
毎に１０回測定して、その平均値と標準偏差を示した。FIG. 3 shows the results of Example 1. The horizontal axis shows the elapsed time (seconds) after applying the potential, and the vertical axis shows the current value (μ
A). The measurement was performed 10 times every 0.5 seconds from 0 to 29.5 seconds after the application of the potential, and the average value and standard deviation were shown.

【図４】図４は実施例１の結果を示したものである。横
軸は電位印加後の経過時間（秒）、縦軸は１０回の測定
値の平均変動率（ＣＶ％）である。FIG. 4 shows the results of Example 1. The horizontal axis represents the elapsed time (seconds) after applying the potential, and the vertical axis represents the average fluctuation rate (CV%) of the measured values of 10 times.

【図５】図５は比較例１の結果を示したものである。横
軸は電位印加後の経過時間（秒）、縦軸は電流値（μ
Ａ）である。電位印加後の０〜２９．５秒まで０．５秒
毎に１０回測定して、その平均値と標準偏差を示した。FIG. 5 shows the results of Comparative Example 1. The horizontal axis shows the elapsed time (seconds) after applying the potential, and the vertical axis shows the current value (μ
A). The measurement was performed 10 times every 0.5 seconds from 0 to 29.5 seconds after the application of the potential, and the average value and standard deviation were shown.

【図６】図６は比較例１の結果を示したものである。横
軸は電位印加後の経過時間（秒）、縦軸は１０回の測定
値の平均変動率（ＣＶ％）である。FIG. 6 shows the results of Comparative Example 1. The horizontal axis represents the elapsed time (seconds) after applying the potential, and the vertical axis represents the average fluctuation rate (CV%) of the measured values of 10 times.

【図７】図７は本発明の別の電気化学測定用セルを例示
した構成部材の斜視図である。FIG. 7 is a perspective view of constituent members exemplifying another electrochemical measurement cell of the present invention.

【図８】図８は本発明の電気化学測定用セルを用いた測
定装置の概略図である。FIG. 8 is a schematic view of a measuring device using the electrochemical measurement cell of the present invention.

【符号の説明】[Explanation of symbols]

１ セル底面 ２ 作用電極 ３ 対極 ４ 銀・塩化銀参照電極 ５ シート材 ６ セル上面 ７ 試料導入口 ８ 空気逃し口 ９ 測定用セル １０ ポテンシオスタット １１ レコーダー 1 Cell bottom surface 2 Working electrode 3 Counter electrode 4 Silver / silver chloride reference electrode 5 Sheet material 6 Cell top surface 7 Sample inlet port 8 Air escape port 9 Measurement cell 10 Potentiostat 11 Recorder

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 作用電極・対極の２電極、または作用電
極・参照電極・対極の３電極を有する電気化学測定用セ
ルであり、測定セル底面と略平行に対向する測定セル上
面との間に被測定試料溶液を保持する空隙を有し、測定
セル底面と測定セル上面との距離が被測定試料溶液を界
面張力で保持できる範囲である電気化学測定用セル。1. An electrochemical measurement cell having two electrodes of a working electrode and a counter electrode, or three electrodes of a working electrode, a reference electrode, and a counter electrode, which is provided between a measurement cell bottom surface and a measurement cell upper surface that are substantially parallel to each other. An electrochemical measurement cell having a void for holding a sample solution to be measured, and a distance between a bottom surface of the measurement cell and an upper surface of the measurement cell is within a range capable of holding the sample solution to be measured by interfacial tension. 【請求項２】 測定セル底面と測定セル上面との距離が
０．１〜５ｍｍである請求項１記載の電気化学測定用セ
ル。2. The electrochemical measurement cell according to claim 1, wherein the distance between the measurement cell bottom surface and the measurement cell top surface is 0.1 to 5 mm. 【請求項３】 少なくとも開口部を２ケ所有する請求項
１記載の電気化学測定用セル。3. The electrochemical measurement cell according to claim 1, which has at least two openings.