JPH05119014A - Method for washing operation electrode of electrode for measuring oxygen - Google Patents
Method for washing operation electrode of electrode for measuring oxygenInfo
- Publication number
- JPH05119014A JPH05119014A JP27917691A JP27917691A JPH05119014A JP H05119014 A JPH05119014 A JP H05119014A JP 27917691 A JP27917691 A JP 27917691A JP 27917691 A JP27917691 A JP 27917691A JP H05119014 A JPH05119014 A JP H05119014A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- working electrode
- nitric acid
- sensitivity
- cleaning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ポーラログラフィの原
理を応用したセベリングハウス型の酸素測定用電極（Ｐ
ｏ2 ）において、使用時間とともに劣化してくる電極特
性(特に、測定感度及び精度)を、簡便な方法にて回復さ
せ、電極の寿命を長くするための、酸素測定用（Ｐ
ｏ2 ）電極の作用極洗浄法及び洗浄液の改良に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seving-house type oxygen measuring electrode (P) applying the principle of polarography.
o 2 ) for oxygen measurement (P 2) to recover the electrode characteristics (particularly measurement sensitivity and accuracy) that deteriorate with use time by a simple method and extend the life of the electrode.
o 2 ) The present invention relates to an electrode cleaning method for an electrode and an improvement in a cleaning solution.
【０００２】[0002]
【従来の技術】従来より、溶液中の酸素濃度変化を測定
する方法として、ポーラログラフィの原理を応用した測
定方法が広く用いられてきた。すなわち白金等の貴金属
細線を、ガラス等の細棒中に封入した作用極部と、銀−
塩化銀等による対極を用い、両極間に、微少電圧を印加
して作用極表面で酸素の還元を行い、この際生じる還元
電流を測定することにより、溶液中の酸素ガス濃度を測
定するものである。上記原理を応用してなるＰｏ2 電極
の構成は、貴金属細線端面をもつ作用極，銀−塩化銀よ
りなる対極と、該作用極部先端に電解液の薄層を保持せ
る酸素選択透過膜からなるが、当該Ｐｏ2 電極の電極特
性を決定ずける。最も重要な留意点は、貴金属細線の端
面を利用した作用極の物理的，化学的状態を常に一定に
保つことにある。しかしながら、本方式によるＰｏ2 電
極はその測定原理上、使用時間とともに、作用極自体
が、脂肪酸等の油脂成分によりコーティングされて、作
用極部での酸素還元反応が妨害されることにより、感度
の低下を招くこと、また、還元反応時、銀−塩化銀より
なる対極で生じる銀イオンが、電解液を通じて、作用極
上に集まり、銀を析出させることにより経時的な感度上
昇をまねいてしまい、測定精度の劣化をまねくといった
問題点を有している。この問題の解決策として、従来よ
り、一定期間使用後に無水エタノールによる浸漬洗浄及
び、ブラシによる作用極上に析出した銀の物理的な除去
が試みられてきた。2. Description of the Related Art Conventionally, as a method for measuring a change in oxygen concentration in a solution, a measuring method applying the principle of polarography has been widely used. That is, a noble metal thin wire such as platinum is enclosed in a thin rod such as glass and a working electrode portion, and silver-
Using a counter electrode such as silver chloride, a minute voltage is applied between both electrodes to reduce oxygen on the surface of the working electrode, and the reduction current generated at this time is measured to measure the oxygen gas concentration in the solution. is there. The structure of the Po 2 electrode applying the above principle comprises a working electrode having an end face of a fine wire of noble metal, a counter electrode composed of silver-silver chloride, and an oxygen selective permeable membrane capable of holding a thin layer of an electrolytic solution at the working electrode tip. However, the electrode characteristics of the Po 2 electrode can be determined. The most important point is to keep the physical and chemical state of the working electrode using the end face of the precious metal wire constant. However, due to the principle of measurement, the Po 2 electrode according to the present method is sensitive to sensitivity due to the fact that the working electrode itself is coated with an oil and fat component such as fatty acid with the use time and interferes with the oxygen reduction reaction at the working electrode part. In addition, in the reduction reaction, silver ions generated at the counter electrode made of silver-silver chloride gathered on the working electrode through the electrolytic solution and deposited silver, leading to an increase in sensitivity over time, which was measured. It has a problem that it causes deterioration of accuracy. As a solution to this problem, it has hitherto been attempted to carry out immersion cleaning with absolute ethanol after a certain period of use and physical removal of silver deposited on the working electrode with a brush.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記従
来技術は、無水エタノールによる洗浄の場合、作用極付
近にこびりついた油脂成分を取り除く力が弱く作用極の
活性化に長時間を要し、また析出した銀の除去は不可能
なこと、また、ブラシを用いた場合、作用極部自体をき
ずつけてしまう危険性があること、等の問題点を有し、
本方式によるＰo2電極の電極感度を一定に維持し、精度
向上、及び長寿命をはかるためのメンテナンス法として
は、十分でなかった。However, in the prior art described above, in the case of washing with anhydrous ethanol, the force for removing the oil and fat component sticking to the vicinity of the working electrode is weak and it takes a long time to activate the working electrode, and the precipitation There is a problem that it is not possible to remove the silver that has been removed, and that when using a brush, there is a risk of scratching the working electrode itself.
This method is not sufficient as a maintenance method for maintaining the electrode sensitivity of the Po 2 electrode constant, improving accuracy, and prolonging the service life.
【０００４】本発明の目的は、かかる問題点を解決し、
Ｐｏ2 電極の電極特性を長期間維持するための簡便なメ
ンテナンス法を提供することにある。The object of the present invention is to solve these problems,
It is to provide a simple maintenance method for maintaining the electrode characteristics of the Po 2 electrode for a long period of time.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、使用時間とともに、汚れて来る作用極の洗浄法とし
て、無水エタノールやブラシを使用するかわりに、銀を
化学的に溶解し、かつ、その酸化作用により油脂成分を
も分解してしまう硝酸を主成分とする水溶液を用いて、
前記作用極を浸漬洗浄することにより、作用極を傷付け
ることなく、しかも短時間に作用極の活性化をはかるこ
とにより、Ｐｏ2 電極性能を長期間維持しようとしたも
のである。[Means for Solving the Problems] In order to achieve the above object, silver is chemically dissolved instead of using absolute ethanol or a brush as a method for cleaning a working electrode that becomes dirty with use time, and , Using an aqueous solution containing nitric acid as a main component, which also decomposes fats and oils due to its oxidizing action,
By dipping and washing the working electrode, the working electrode is not damaged, and the working electrode is activated in a short time to maintain Po 2 electrode performance for a long period of time.
【０００６】[0006]
【作用】使用時間とともに、銀の析出や油脂成分による
汚染により不安定化するＰｏ2 電極の作用極の洗浄法と
し、硝酸を主成分とする水溶液を用いた場合、硝酸のも
つ弱い酸化力により、銀及び油脂成分を両者同時かつ短
時間で、溶解及び分解することができ、かつ、作用極と
なっている白金等の貴金属細線をいためることはない。
この場合硝酸の濃度と、処理時間の関係は反比例の関係
となるが、０.５規定以下にすると、硝酸としての酸化
作用が弱まり、処理時間として１時間以上を要し簡便な
メンテナンス法として不適当となる。[Function] As a method for cleaning the working electrode of the Po 2 electrode, which becomes unstable due to the precipitation of silver and the contamination with fats and oils with the time of use, when an aqueous solution containing nitric acid as the main component is used, the weak oxidizing power of nitric acid causes , Silver and fats and oils components can be dissolved and decomposed at the same time in a short time, and the fine wire of precious metal such as platinum, which is the working electrode, is not damaged.
In this case, the relationship between the concentration of nitric acid and the treatment time is inversely proportional, but if it is less than 0.5 normal, the oxidizing action as nitric acid is weakened, and the treatment time requires 1 hour or more, which is not suitable as a simple maintenance method. Will be appropriate.
【０００７】以上のことから、Ｐｏ2 電極の作用極洗浄
法として、０.５ 規定以上の硝酸を主成分とする水溶液
による浸漬洗浄をとり入れることにより原理上想定され
る汚れに対し、一種類の洗浄液にて、短時間にしかも作
用極自体をきずつけることなく活性化をはかることがで
き、Ｐｏ2 電極の特性を簡便なメンテナンスにより長期
間維持できるようになる。From the above, as a working electrode cleaning method for the Po 2 electrode, by incorporating immersion cleaning with an aqueous solution containing nitric acid of 0.5 N or more as a main component, one type of contamination against the contamination supposed in principle can be obtained. The cleaning liquid can be activated in a short time without scratching the working electrode itself, and the properties of the Po 2 electrode can be maintained for a long time by simple maintenance.
【０００８】[0008]
【実施例】以下、本発明の一実施例を図１〜図３により
説明する。本発明が使用されるＰｏ2 電極は図１に示す
通り１の酸素選択透過膜、２の白金作用極がガラス中に
封入され、かつ、３の銀−塩化銀対極をもち、４の電解
液，５のＯリング及び６のリード線により構成され、そ
の電池式は以下のようになる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the Po 2 electrode used in the present invention has an oxygen selective permeable membrane 1 as shown in FIG. 2, a platinum working electrode as 2 is enclosed in glass, and has a silver-silver chloride counter electrode as 3 and an electrolytic solution as 4 , 5 O-rings and 6 lead wires, the battery type of which is as follows.
【０００９】[0009]
【数１】 [Equation 1]
【００１０】上記電池式において、作用極と対極間に
０.７Ｖ の直流電圧を作用極をマイナスとして加える
と、白金表面でＯ2 はＯＨ- に還元され、Ｏ2 は分子一
ケの還元により４ケの電子を消費する。ここで、血液試
料等をテフロン膜を隔てて、作用極面に接しておくと、
膜を透過したＯ2 は作用極で逐次消費され、相当する電
流が流れることになる。そして試料中に均一に存在して
いるＯ2 分子が、Ｏ2濃度ゼロになる白金表面の状態を
戻すべく作用極にむかってゆるやかに拡散していくこと
になる。白金作用極でＯ2 での消費速度とこの拡散によ
って白金面に供給される速度とが等しくなった時点で、
この還元反応系を流れる電流は一定となる。この時の電
流値を読み取りＰｏ2 濃度を計測できるようになってい
る。In the above battery-powered, the addition of a DC voltage of 0.7V between the working electrode and the counter electrode the working electrode as a negative, O 2 in the platinum surface is OH - are reduced to, O 2 by reduction of the molecule one Ke Consume 4 electrons. Here, when a blood sample or the like is placed in contact with the working electrode surface across the Teflon membrane,
O 2 that has permeated the film is successively consumed by the working electrode, and a corresponding current flows. Then, the O 2 molecules that are uniformly present in the sample diffuse gradually toward the working electrode in order to restore the state of the platinum surface where the O 2 concentration becomes zero. When the consumption rate of O 2 at the platinum working electrode becomes equal to the rate of supply to the platinum surface by this diffusion,
The current flowing through this reduction reaction system is constant. The current value at this time is read and the Po 2 concentration can be measured.
【００１１】図２に、上記Ｐｏ2 電極の使用時間による
電極感度の変化と、本発明による洗浄の効果を示す。先
にのべたように、本方式によるＰｏ2 電極は、原理上時
間経過とともに、銀析出や油脂成分の作用極へのコーテ
ィング等により、電極感度が変化するが、多くの場合、
銀析出による作用極面積増大に伴う感度増大よりも、油
脂成分等のコーティングによる作用極のマスキング作用
が優先し、電極感度が低下し、それに伴って測定精度も
劣化する。しかしながら本発明による洗浄液（５ＮＨＮ
Ｏ3 使用）により５分間浸漬洗浄することにより、図２
に示すごとく、感度が初期状態に復帰し、安定で高精度
なＰｏ2 濃度計測が可能となる。FIG. 2 shows changes in the electrode sensitivity with the use time of the Po 2 electrode and the effect of cleaning according to the present invention. As mentioned above, the Po 2 electrode according to this method changes the electrode sensitivity due to the deposition of silver or the coating of the oil and fat component on the working electrode in principle over time, but in many cases,
The masking action of the working electrode by coating with a fat or oil component has priority over the increase in sensitivity due to the increase in the working electrode area due to silver deposition, and the electrode sensitivity decreases, and the measurement accuracy accordingly deteriorates. However, the cleaning solution according to the present invention (5NHN
2 ) by immersion cleaning with O 3 ) for 5 minutes.
As shown in, the sensitivity returns to the initial state, and stable and highly accurate Po 2 concentration measurement becomes possible.
【００１２】図３に、本発明による洗浄液の硝酸濃度
と、電極感度を初期状態に戻すのに要する処理時間の関
係を示す。硝酸濃度が高くなれば、処理時間が短くてす
むが、処理時間の安全上の危険性がますこと、また硝酸
濃度が０.５規定以下になると、硝酸の酸化作用がほと
んどなくなるため、処理効果が上がらなくなり、長時間
処理が必要となって簡便なメンテナンス法としては不適
当となるため、実用上は１〜１ＯＮの硝酸を主成分とす
る水溶液を使用するのが望ましい。FIG. 3 shows the relationship between the nitric acid concentration of the cleaning solution according to the present invention and the processing time required to restore the electrode sensitivity to the initial state. If the nitric acid concentration is high, the treatment time will be short, but there is a safety risk in the treatment time. Also, if the nitric acid concentration is less than 0.5 standard, the oxidizing effect of nitric acid will almost disappear, so the treatment effect However, it is not suitable as a simple maintenance method because it requires a long treatment time. Therefore, it is practically preferable to use an aqueous solution containing 1 to 1 ON of nitric acid as a main component.
【００１３】[0013]
【発明の効果】本発明によれば、Ｐｏ2 電極の作用極
を、使用開始一定期間毎に（約２ケ月）硝酸を主成分と
する水溶液により浸漬洗浄することにより、短時間（約
５〜１０分）にて、作用極面の汚れを除去し、作用極を
簡単にリフレッシュすることができ、それによって電極
感度の安定性及び精度を、長期間維持することができる
ようになった。According to the present invention, the working electrode of the Po 2 electrode is dipped and washed with an aqueous solution containing nitric acid as a main component at regular intervals (about 2 months) after the start of use, so that the working electrode can be used for a short time (about 5 months). After 10 minutes, the working electrode surface was cleaned and the working electrode could be easily refreshed, whereby the stability and accuracy of the electrode sensitivity could be maintained for a long period of time.
【図１】本発明の対象となるＰｏ2 電極の断面図であ
る。FIG. 1 is a cross-sectional view of a Po 2 electrode which is a target of the present invention.
【図２】Ｐｏ2 電極の感度経時変化と本発明による洗浄
法による効果を示す図である。FIG. 2 is a diagram showing a change with time of sensitivity of a Po 2 electrode and an effect of a cleaning method according to the present invention.
【図３】本発明による硝酸濃度と、Ｐｏ2 電極作用極処
理時間の関係を示す図である。FIG. 3 is a graph showing the relationship between the nitric acid concentration according to the present invention and the Po 2 electrode working electrode treatment time.
１…酸素選択透過膜、２…白金作用極、３…銀−塩化銀
対極、４…電解液、５…Ｏリング、６…リード線、７…
電極感度の経時変化を示すグラフ、８…硝酸濃度と処理
時間の関係を示すグラフ。1 ... Oxygen selective permeable membrane, 2 ... Platinum working electrode, 3 ... Silver-silver chloride counter electrode, 4 ... Electrolyte solution, 5 ... O-ring, 6 ... Lead wire, 7 ...
A graph showing a change with time of the electrode sensitivity, a graph showing the relationship between the nitric acid concentration and the treatment time.
Claims (2)
に封入され、かつ、貴金属細線端面を保持してなる作用
極部と、該作用極部先端に電解液の薄層を保持せる酸素
選択透過膜とを備えた酸素測定用電極において、前記作
用極部を、硝酸を主成分とする水溶液にて、洗浄するこ
とを特徴とする酸素測定用電極の作用極洗浄法。1. A working electrode part in which a noble metal fine wire such as platinum is enclosed in a thin rod such as glass, and an end face of the noble metal thin wire is held, and a thin layer of an electrolytic solution is held at the tip of the working electrode part. A method for cleaning a working electrode of an oxygen measuring electrode, comprising: cleaning the working electrode portion with an aqueous solution containing nitric acid as a main component.
を特徴とする請求項１記載の酸素測定用電極の作用極洗
浄法。2. The working electrode cleaning method for an oxygen measuring electrode according to claim 1, wherein the concentration of nitric acid is 0.5 N or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27917691A JPH05119014A (en) | 1991-10-25 | 1991-10-25 | Method for washing operation electrode of electrode for measuring oxygen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27917691A JPH05119014A (en) | 1991-10-25 | 1991-10-25 | Method for washing operation electrode of electrode for measuring oxygen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05119014A true JPH05119014A (en) | 1993-05-14 |
Family
ID=17607507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27917691A Pending JPH05119014A (en) | 1991-10-25 | 1991-10-25 | Method for washing operation electrode of electrode for measuring oxygen |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05119014A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008056696A1 (en) | 2006-11-08 | 2008-05-15 | Horiba, Ltd. | Washing storage solution for glass electrode and the like |
-
1991
- 1991-10-25 JP JP27917691A patent/JPH05119014A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008056696A1 (en) | 2006-11-08 | 2008-05-15 | Horiba, Ltd. | Washing storage solution for glass electrode and the like |
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