JPS6243556A - Silver electrode for enzyme electrode - Google Patents

Abstract

PURPOSE:To eliminate the lowering of activity with an excellent response, by mixing silver powder with a specified amount of silver chloride and silver sulfide and then, with an epoxy resin to form the silver pole of a hydrogen peroxide electrode by pressure molding. CONSTITUTION:0.5-10wt% of a mixture of silver chloride and silver sulfide is added to silver powder. The amount of the silver chloride shall be 10-90% in the mixture. The mixture of these three components is mixed with 0.5-5wt% of epoxy resin and the pressure molding is done by the pressure of 0.3-2.5 ton/cm<2>. An electrode comprising silver, silver chloride, silver sulfide and the epoxy resin is built and a platinum electrode 18 is provided at the center thereof to form a solid electrode. This electrode is used as hydrogen peroxide electrode. Thus, the use of the electrode thus obtained can increase the activity with an excellent linearity and response thereby assuring a long-time stability.

Description

【発明の詳細な説明】 〔発明の属する技術分野〕 この発明は、固定化酵素膜を用いる酵素電極の一部であ
る過酸化水素電極のカソードに適用される銀電極に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to a silver electrode applied to the cathode of a hydrogen peroxide electrode, which is a part of an enzyme electrode using an immobilized enzyme membrane.

〔従来技術とその問題点〕[Prior art and its problems]

一般に酵素電極は、選択性、迅速性、正確性等が優れて
いることから、臨床化学分析や食品分析等の分野で広く
利用されている。酵素電極を構成する電極の一種である
過酸化水素電極は、酵素の触媒作用により生成した過激
化水素を白金等を用いたアノードで酸化し、この時に生
じる酸化電流値から特定成分を定量する目的で使用され
ている。In general, enzyme electrodes are widely used in fields such as clinical chemical analysis and food analysis because of their excellent selectivity, rapidity, and accuracy. A hydrogen peroxide electrode, which is a type of electrode that makes up an enzyme electrode, is used to oxidize radicalized hydrogen generated by the catalytic action of an enzyme using an anode made of platinum or the like, and quantify specific components from the oxidation current value generated at this time. used in

すなわち、前記過酸化水素電極を使用して過酸化水素の
濃度を計測するに際しては、白金をアノードとし銀をカ
ソードとして使用し、これら両電極間に一定電圧を印加
して電解電流を測定し、検量線法もしくは校正法により
過酸化水素量を決定するのが一般的である。That is, when measuring the concentration of hydrogen peroxide using the hydrogen peroxide electrode, platinum is used as an anode and silver is used as a cathode, and a constant voltage is applied between these two electrodes to measure the electrolytic current. The amount of hydrogen peroxide is generally determined by a calibration curve method or a calibration method.

また、この種の酵素電極については、その取扱上次のよ
うな性能が要求される。Furthermore, this type of enzyme electrode is required to have the following performance in its handling.

（１）応答性：短いものほど好ましい。(1) Responsiveness: The shorter the response, the better.

伐）直線性：濃度の高い領域まで直線関係を示すものが
好ましい。Linearity: It is preferable to show a linear relationship up to the region of high concentration.

（３）活性度：反応量に応じて電極間に発生する電流の
大小で、電流値が大きいほど活 性度が高く好ましい。(3) Activity: The magnitude of the current generated between the electrodes depending on the amount of reaction, and the larger the current value, the higher the activity, which is preferable.

（４）安定性二反応量に応じて電極間に発生する電流値
が経時的変化を示さない、又は 変化が小さいことが好ましい０ ところで、酵素電極のカソードとして使用される銀電極
は、一般に溶屏加工材を機械加工によって所定の電極形
状に構成したものである。このように構成される銀電極
は、応答性および直線性は大略良好であるが、長時間の
使用によって活性度が低下する欠点がある。活性度の劣
化は、銀電極の電位変動あるいは酸化物の形成などによ
り引き起こされると考えられ、精度の低下と検出限界能
の悪化を招来し、劣化が著しい場合には過酸化水素量を
決定する校正法が適用できな（なる難点がある。(4) Stability It is preferable that the current value generated between the electrodes depending on the amount of reaction does not change over time, or that the change is small.By the way, the silver electrode used as the cathode of the enzyme electrode is generally A folding material is machined into a predetermined electrode shape. Although the silver electrode constructed in this manner has generally good response and linearity, it has the disadvantage that the activity decreases when used for a long time. The deterioration of activity is thought to be caused by potential fluctuations of the silver electrode or the formation of oxides, leading to a decrease in accuracy and a deterioration of the detection limit ability.If the deterioration is significant, the amount of hydrogen peroxide should be determined. There is a drawback that the calibration method cannot be applied.

また銀粉末を加圧成形する方法も徨々知られているが、
活性度の劣化の根本的な原因と考えられる銀電極の電位
変動は避けられない。There are also many known methods of press-molding silver powder.
Potential fluctuations of the silver electrode, which are considered to be the fundamental cause of activity deterioration, cannot be avoided.

活性度の劣化、あるいは安定性の向上のために、上述し
た銀電極の表面を電気メツキ法により銀／塩化銀の薄膜
を耐着させ、電極電位の変動をおさえる方法が知られて
いるが、この薄膜耐着は機械的あるいは物理的な損傷を
受けやすい。酵素電極では、数回に及ぶ固定化酵素膜の
交換により一部剥離状態になるといった欠点がある。ま
た銀／塩化銀化に長時間を要する。電解メッキ液の管理
に注意を要する。充電効果が認められるといった難点も
知られている。In order to reduce activity deterioration or improve stability, a method is known in which a thin film of silver/silver chloride is adhered to the surface of the silver electrode by electroplating to suppress fluctuations in electrode potential. This thin film adhesion is susceptible to mechanical or physical damage. Enzyme electrodes have the disadvantage that the immobilized enzyme membrane becomes partially peeled off after being replaced several times. Further, it takes a long time to form silver/silver chloride. Care must be taken in managing the electrolytic plating solution. It is also known to have some drawbacks, such as a charging effect.

一方、電位測定法に用いるイオン選択性電極の一種であ
るハロゲン化銀電極の製法で、化学的に不活性な塩化銀
と硫化鋼を混合してプレスすると良好な電極材料が得ら
れることが知られている。On the other hand, in the production of silver halide electrodes, which are a type of ion-selective electrode used in potential measurement, it is known that a good electrode material can be obtained by mixing and pressing chemically inert silver chloride and sulfide steel. It is being

しかしながら、このように製作される電極材は電気抵抗
が１０番〜１０１オーム／ａｎと大きく、電位測定法に
は適用できるが、過酸化水素電極のような電流測定法の
電極材料としては電極の内部抵抗が大きくなり不適であ
る。このため一般的には使用されていない。However, the electrode material manufactured in this way has a large electrical resistance of 10 to 101 ohms/an, and can be applied to potential measurement methods, but it is not suitable for electrode materials for current measurement methods such as hydrogen peroxide electrodes. It is unsuitable because the internal resistance becomes large. For this reason, it is not generally used.

〔発明の目的〕[Purpose of the invention]

この発明は上記に鑑みなされたもので、過酸化水素電極
として応答性と直線に優れ、活性度の低下、すなわち安
定性に優れた酵素電極用銀電極を提供することを目的と
する０ 〔発明の要点〕 本発明者等は、前述した従来の酵素電極用銀電極の問題
点を全て克服すべく檻々検討並びに試作を重ねた結果、
銀粉末に重量で０．５〜１０チの塩化銀と硫化銀の混合
物を添加し、この３成分を混合・攪拌し、さらに重量で
０．５〜５％のエポキシ樹脂を含有させ充分に混練した
後、これらを所定の電極形状に圧縮成形して一体化する
ことにより得られた電極は、酵素電極として使用した場
合、充分な直線性、応答性と安定性が得られ、前記問題
点を解消し得ることを突き止めた。This invention was made in view of the above, and an object of the invention is to provide a silver electrode for an enzyme electrode that has excellent responsiveness and linearity as a hydrogen peroxide electrode, and has low activity, that is, excellent stability. [Key Points] As a result of repeated studies and trial production in order to overcome all the problems of the conventional silver electrode for enzyme electrodes mentioned above, the present inventors found that
A mixture of 0.5 to 10 grams of silver chloride and silver sulfide is added to the silver powder, these three components are mixed and stirred, and 0.5 to 5% of the epoxy resin is added by weight and thoroughly kneaded. After that, the electrode obtained by compression molding and integrating these into a predetermined electrode shape has sufficient linearity, responsiveness and stability when used as an enzyme electrode, and solves the above problems. I found out that there is a solution.

この発明は、溶液と接する銀電極表面を銀／塩化銀化す
ることにより、電極電位の安定化と電極反応の可逆性の
向上を図り、かつ硫化銀と塩化銀の混合物を用いること
で、従来知られている塩化銀単独の欠点（やわらかい、
電気抵抗が太きい。This invention aims to stabilize the electrode potential and improve the reversibility of the electrode reaction by coating the surface of the silver electrode in contact with the solution with silver/silver chloride, and by using a mixture of silver sulfide and silver chloride, The known drawbacks of silver chloride alone (soft,
Electrical resistance is high.

充電効果がある）を補い、さらに銀粉と塩化銀と硫化銀
を所定の重量％で混合、攪拌した後、エポキシ樹脂を添
加し加圧成形するため電極材の電気抵抗を電流測定上に
実質的）こ不都合がない程度に下げることができ、かつ
機械加工に耐え得る強度を持たせようとするものである
。要するに、電位安定性、電気伝導性９機械的強度に優
れた銀−塩化銀一硫化鍋一エポキシ樹脂から成る銀電極
を加圧成形法により製造することによって、安定性が向
上した酵素電極用銀電極を見い出したものである０ 〔発明の実施例〕 以下に、本発明に係る酵素電極用銀電極の実施例として
、過酸化水素電極を例示し、図面と共に詳細に説明する
０ 第１図は銀電極の成形状態を示し、第２図は第１図に示
す銀電極をさらに加工して構成した過酸化水素電極を示
すものである。まず、市販の銀粉末（−３２５メツシユ
）と、エポキシ樹脂（商品名工ピコ−）８１５）と、適
当な重量比でよく混り合った塩化銀と硫化銀との混合物
（所定濃度の塩化ナトリウムと硫化ナトリウムの混合溶
液に２倍量過剰の硝酸塩溶液を加え、生成した沈澱を２
０回蒸留水で洗浄し、１１０℃で乾燥したものでよい）
と、所望の形状の銀リード線とを用意する・・次いで、
銀リード線を金型内に装着した後、塩化銀と硫化銀から
成る混合物（塩化銀の重量係が１０〜９０）を銀粉とよ
く混合（塩化銀と硫化銀の混合物の重量％が０．５〜１
０になるようにする）、攪拌し、次に前記３成分を含む
混合物をエポキシ樹脂（０，５重量嗟以上で５重量％以
下）と充分に混練する。そして、この混練された混合粉
を金型に充填する。その後、前記金型において０．３〜
１．５　ｔｏｎ／ｄの圧力下に充填材を圧縮成形するこ
とにより、第１図に示す形状の銀電極１０を得ることが
できる。なお、第１図において参照符号１２は銀リード
線を示し、１４は銀−塩化銀一硫化錯−エポキシ樹脂成
形体を示す。After mixing and stirring silver powder, silver chloride, and silver sulfide at a predetermined weight percentage, epoxy resin is added and pressure molded, so the electrical resistance of the electrode material can be effectively measured by current measurement. ) The objective is to reduce the thickness to a level that causes no inconvenience, and to provide strength that can withstand machining. In short, by producing a silver electrode made of silver-silver chloride monosulfide pot-epoxy resin with excellent potential stability, electrical conductivity, and mechanical strength using a pressure molding method, silver for enzyme electrodes has improved stability. [Embodiments of the Invention] Below, as an embodiment of the silver electrode for enzyme electrodes according to the present invention, a hydrogen peroxide electrode will be exemplified and explained in detail with drawings. The molded state of the silver electrode is shown, and FIG. 2 shows a hydrogen peroxide electrode constructed by further processing the silver electrode shown in FIG. 1. First, commercially available silver powder (-325 mesh), epoxy resin (trade name: Pico-815), and a mixture of silver chloride and silver sulfide mixed well in an appropriate weight ratio (sodium chloride at a predetermined concentration and Add 2 times excess of nitrate solution to the mixed solution of sodium sulfide, and add 2 times the amount of the produced precipitate.
(It may be washed with 0 times distilled water and dried at 110℃)
and a silver lead wire of the desired shape...Next,
After the silver lead wire is installed in the mold, a mixture of silver chloride and silver sulfide (the weight ratio of silver chloride is 10 to 90) is thoroughly mixed with silver powder (the weight percentage of the mixture of silver chloride and silver sulfide is 0. 5-1
The mixture containing the above three components is thoroughly kneaded with an epoxy resin (0.5% by weight or more and 5% by weight or less). Then, this kneaded mixed powder is filled into a mold. After that, in the mold, 0.3~
By compression molding the filler under a pressure of 1.5 ton/d, a silver electrode 10 having the shape shown in FIG. 1 can be obtained. In FIG. 1, reference numeral 12 indicates a silver lead wire, and 14 indicates a silver-silver chloride monosulfide complex-epoxy resin molded body.

このように構成した銀電極１０は、第２図に示すように
、中心部に貫通孔１６を設け、この中心孔１６内にアノ
ードとしての白金棒からなる白金電極１８を挿通配置す
ると共に、この白金電極１８の周囲に絶縁材としてのエ
ポキシ樹脂２０を注型して固定する。なお、白金電極１
８には適宜銀リード線２２を接続する。このようにして
、過酸化水素電極を構成することができる。As shown in FIG. 2, the silver electrode 10 configured in this manner has a through hole 16 in the center, and a platinum electrode 18 made of a platinum rod serving as an anode is inserted through the center hole 16. Epoxy resin 20 as an insulating material is cast around the platinum electrode 18 and fixed. In addition, platinum electrode 1
A silver lead wire 22 is connected to the terminal 8 as appropriate. In this way, a hydrogen peroxide electrode can be constructed.

この際、塩化銀と硫化銀から成る混合物の組成において
塩化銀の重量比で１０〜９０％とした理由は、９０９ｂ
以上ではもろいことと、光電効果が大きいためであり、
１０％以下では銀／塩化銀としての安定した電極電位が
得られないためである。At this time, the reason why the weight ratio of silver chloride in the composition of the mixture consisting of silver chloride and silver sulfide was set at 10 to 90% was because 909b
This is because it is brittle and has a large photoelectric effect.
This is because if it is less than 10%, a stable electrode potential as silver/silver chloride cannot be obtained.

更に、銀粉と前記混合物の混合において、前記混合物の
占める割合を重量比で０．５〜１０ｍと限定した理由は
、０．５％以下では銀／塩化銀電極の示す安定した電極
が得られず単なる銀電極とほぼ同等の特性しか得られな
いためであり、１０％以上では電気抵抗が大きくなり電
流測定用銀電極としては内部抵抗が大きくなってしまう
ことと、機械的強度が充分確保できないためである。Furthermore, in mixing silver powder and the above mixture, the reason why the proportion of the above mixture was limited to 0.5 to 10 m by weight is that if it is less than 0.5%, a stable electrode as exhibited by the silver/silver chloride electrode cannot be obtained. This is because the characteristics are almost the same as those of a simple silver electrode, and if it exceeds 10%, the electrical resistance increases and the internal resistance becomes too large to be used as a silver electrode for current measurement, and the mechanical strength cannot be ensured sufficiently. It is.

更にまた、銀粉−塩化銀一硫化銀から成る混合粉末に対
しエポキシ樹脂を重量比で５チ以下添加する理由は、エ
ポキシ樹脂が５％以上添加されると、圧縮成形時にエポ
キシ樹脂が浸み出して電極表面を覆ってしまう現象が発
生し、これにより酵素電極としての直線性、応答性が低
下するためである。また、エポキシ樹脂含有量を０．５
％以上とする理由は、これ以下であると銀電極中心部に
孔部を設ける際の機械加工が出来ず、しかも活性度の劣
化が銀のみの電極と同様に著しくなるためである。Furthermore, the reason why epoxy resin is added at a weight ratio of 5 or less to the mixed powder consisting of silver powder and silver chloride monosulfide is that if 5% or more of epoxy resin is added, the epoxy resin will ooze out during compression molding. This is because a phenomenon occurs in which the electrode surface is covered by the enzyme, which deteriorates the linearity and responsiveness of the enzyme electrode. In addition, the epoxy resin content was reduced to 0.5
% or more, because if it is less than this, machining cannot be performed when forming a hole in the center of the silver electrode, and furthermore, the deterioration in activity will be as significant as in an electrode made only of silver.

このようにして製造した銀電極を過酸化水素電極として
製作するに際しては、第２図に示す電極の表面を固定化
酵素（グルコースオキシダーゼ）膜で密着被覆する。次
いで、このように構成した酵素電極をｐＨ７のリン酸緩
衝溶液を備える測定槽内に設置して、前記酵素電極を前
記緩衝溶液中に浸し、白金電極１８には銀電極１４に対
し常に０、６５　Ｖの電位差を有するようにポーラログ
ラフ装置などにより電圧を印加する。When fabricating the silver electrode thus produced as a hydrogen peroxide electrode, the surface of the electrode shown in FIG. 2 is closely coated with an immobilized enzyme (glucose oxidase) membrane. Next, the enzyme electrode configured in this way is placed in a measurement tank containing a phosphate buffer solution with a pH of 7, and the enzyme electrode is immersed in the buffer solution, and the platinum electrode 18 is always 0, A voltage is applied using a polarographic device or the like so as to have a potential difference of 65 V.

このような条件下において、過酸化水素電極を使用し、
例えば血液中のグルコース濃度を測定するものとすれば
、グルコースは固定化酵素膜の作用下に次のような反応
を生じる。Under these conditions, using a hydrogen peroxide electrode,
For example, when measuring the glucose concentration in blood, glucose undergoes the following reaction under the action of an immobilized enzyme membrane.

グルコースオキシダーゼ グルコース＋Ｏｘ　　　　　　　　　　　　　グルコン
酸十ＨｔＯｔ・・・・・・　（１） グルコースの分解で生成した過酸化水素は白金電極で酸
化され、銀電極では散票が還元され、それぞれ次式に示
すような反応電流が生じる。Glucose oxidase Glucose + Ox Gluconic acid 10HtOt... (1) Hydrogen peroxide produced by the decomposition of glucose is oxidized at the platinum electrode, and powder is reduced at the silver electrode, resulting in the reactions shown in the following equations. A current is generated.

前記式（２）に示される反応電流を実測することにより
、グルコース濃度を換算することができる。By actually measuring the reaction current shown in the above formula (2), the glucose concentration can be converted.

前述した方法により、過酸化水素電極で測定される前記
（１）及び（２）式に基づく応答性を第３図に示す。グ
ルコース溶液と接触後１０秒程度で定常状態に達する良
好な応答性を有することがわかる。FIG. 3 shows the responsivity based on equations (1) and (2) above, measured with a hydrogen peroxide electrode by the method described above. It can be seen that it has good responsiveness, reaching a steady state in about 10 seconds after contact with the glucose solution.

本発明品の効果を確認するため、塩化銀を５０重量％含
む塩化銀−硫化銀から成る混合物を重量比で５％を含む
銀−塩化銀一硫化銀からなる混合粉末と重量で５チのエ
ポキシ樹脂と混練し、成形圧１．０ｔｏｎ／ｃＩ／ｌで
加工成形した本発明品と銀電極として溶解加工材を機械
加工したものを使用した従来品を使って、過酸化水素の
ポルタングラムを測定した。In order to confirm the effect of the product of the present invention, a mixture of silver chloride and silver sulfide containing 50% by weight of silver chloride was mixed with a mixed powder of silver chloride and silver monosulfide containing 5% by weight of 5% by weight. Portangrams of hydrogen peroxide were produced using the present invention, which was kneaded with epoxy resin and processed and molded at a molding pressure of 1.0 ton/cI/l, and the conventional product, which was made by machining a melted material as a silver electrode. It was measured.

第４図から明らかなように、本発明品〔特性曲線Ａ〕で
は約０．６〜０．７　Ｖの範囲で定常状態が得られるが
、従来品〔特性曲線Ｂ〕では１．　ＯＶでも定常状態に
達していない。このことは、本発明品は測定溶液中の還
元性物質の影響を受けにくい（例えば、０．６５Ｖで過
酸化水素の測定を行えば、１、０　Ｖ前後で酸化される
物質の影響は実質的１こ無視できるが、従来品で電流値
を稼ごうとして１．　ＯＶで過酸化水素の測定を行なう
と、還元性物質の妨害が無視できないことを意味する）
ことがわかる。更に、本発明品では、電極活性は０．６
５±０．０５Ｖ程度の印加電圧変動には大きく左右され
ないことが明らかである。一方、従来品では±１５−の
出力変動をもたらす。As is clear from FIG. 4, the product of the present invention [characteristic curve A] can obtain a steady state in the range of approximately 0.6 to 0.7 V, while the conventional product [characteristic curve B] has a steady state of 1. Even at OV, steady state has not been reached. This means that the product of the present invention is less susceptible to the effects of reducing substances in the measurement solution (for example, if hydrogen peroxide is measured at 0.65 V, the effects of substances that are oxidized at around 1.0 V will be substantially eliminated). (This means that the interference of reducing substances cannot be ignored when measuring hydrogen peroxide using OV.)
I understand that. Furthermore, in the product of the present invention, the electrode activity is 0.6
It is clear that it is not greatly influenced by applied voltage fluctuations of about 5±0.05V. On the other hand, the conventional product causes an output fluctuation of ±15-.

更に、鋼種の電極電位の変動を経時的に測定したところ
、本発明品は１週間にわたりその変動は１０ｍＶ前後で
あったが、従来品は１００〜２００ｍＶ変動するものが
あり、過酸化水素電極の安定性の面からも本発明品の優
位性が明らかとなった。Furthermore, when we measured the variation in the electrode potential of steel types over time, the variation was around 10 mV for the product of the present invention over a period of one week, whereas the variation for the conventional product was 100 to 200 mV. The superiority of the product of the present invention was also revealed in terms of stability.

前述した方法により、過酸化水素電極で測定される前記
（２）式に基づく反応電流値（ｎＡ）とグルコース濃度
（ｍｇ／ｄ　ｌ　）との特性を示せば第５図に示す通り
である。なお、本発明品〔特性曲線Ａ〕の効果を確認す
るため、従来品〔特性曲線Ｂ〕との比較を行なった。第
５図から明らかなように、本発明品は従来品に比べて直
線性が優れている（少なくとも同等以上）ことが確認さ
れた。The characteristics of the reaction current value (nA) based on the equation (2) and the glucose concentration (mg/dl) measured using the hydrogen peroxide electrode by the method described above are shown in FIG. In order to confirm the effect of the product of the present invention [characteristic curve A], a comparison was made with a conventional product [characteristic curve B]. As is clear from FIG. 5, it was confirmed that the product of the present invention has superior linearity (at least equivalent or better) than the conventional product.

本発明品と従来品との過酸化水素６ｐｐｍに対する活性
度をそれぞれ５本製作し、測定した結果、第１表に示す
通り、本発明品の活性度が優れていることが明らかとな
った。このことは第４図からも理解できることである。The activity of the product of the present invention and the conventional product against 6 ppm of hydrogen peroxide was measured by manufacturing five bottles each, and as shown in Table 1, it was found that the product of the present invention had excellent activity. This can also be understood from Figure 4.

第　　１　　表 更に、活性度の劣化について経時的に観察した結果、第
６図に示すような特性が得られた。第６図から明らかな
ように、本発明品〔特性曲線Ａ〕は、従来品〔特性曲線
Ｂ〕に比べて劣化が著しく小さく、長時間にわたって初
期状態を保持し得る安定性を示すことが確認された。Table 1 Furthermore, as a result of observing the deterioration of activity over time, the characteristics shown in FIG. 6 were obtained. As is clear from Figure 6, the product of the present invention [characteristic curve A] has significantly less deterioration than the conventional product [characteristic curve B], and it has been confirmed that it exhibits stability that allows it to maintain its initial state for a long period of time. It was done.

〔発明の効果〕〔Effect of the invention〕

前述した実施例から明らかなように、本発明に係る銀電
極は、これを固定化酵素膜を使用する酵素電極として構
成した場合、直線性、応答性に優れた効果を発揮するこ
とは勿論のこと、特に従来の酵素電極に比べて活性度を
増大させることができると共に長期間にわたって活性度
の低下も殆んどなく、酵素電極としての信頼性を高める
ことができる。As is clear from the above examples, the silver electrode according to the present invention not only exhibits excellent linearity and responsiveness when configured as an enzyme electrode using an immobilized enzyme membrane. In particular, the activity can be increased compared to conventional enzyme electrodes, and there is almost no decrease in activity over a long period of time, making it possible to improve reliability as an enzyme electrode.

従って、本発明に係る酵素電極用銀電極は、過酸化水素
検出用隔膜被覆電極として好適ｌこ応用することができ
、臨床化学分析や食品分析、環境分析に広く適用するこ
とができる。また、電極の性能向上と相俟って、有機分
析や化学プロセス制御の分野１こもその利用を拡大する
ことができる。Therefore, the silver electrode for an enzyme electrode according to the present invention can be suitably applied as a diaphragm-coated electrode for detecting hydrogen peroxide, and can be widely applied to clinical chemical analysis, food analysis, and environmental analysis. In addition, along with improved electrode performance, its use can be expanded to the fields of organic analysis and chemical process control.

また、製造工程（秤量→混合→混練→成形）は長時間を
要する電気メツキ工程を含まず、かつ容易に得られるた
め、電極電位の安定した電流測定用銀電極として経済性
に於ても優れていることは明らかである。In addition, the manufacturing process (weighing → mixing → kneading → molding) does not include the electroplating process, which takes a long time, and is easy to obtain, so it is economically viable as a silver electrode for current measurement with a stable electrode potential. It is clear that

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

第１図は本発明に係る銀電極の成形状態の一実施例を示
す一部断面図、第２図は第１図に示す銀電極を使用して
過酸化水素電極を構成した実施例を示す一部断面図、第
３図は第２図に示す過酸化水素電極の応答性を示す特性
曲線図、第４図は第２図に示す過酸化水素電極と従来の
過酸化水素電極を用いたときのポルタングラムの相違を
示す特性曲線図、第５図は第２図に示す過酸化水素電極
と従来の過酸化水素電極との直線性を比較した特性曲線
図、第６図は第２図に示す過酸化水素電極と従来の過酸
化水素電極との活性度の経時的変化を比較した特性曲線
図である。 １０・・・銀電極、１２・銀リード線、１４・・・銀−
塩化銀−硫化銀−エポキシ樹脂成形体、１６・・貫通孔
、１８・・・白金電極、２０・・・エポキシ樹脂、２２
　・銀リード線。 才１　口 ｌε 才２０ θ　　　　３０　　　　乙ＯｑＯ 坪ｆｆｌ　（Ｐｆ） 才３Ｉ￥１ ＥＣＶｖａＡ７径） オ／Ｌ喝FIG. 1 is a partial cross-sectional view showing an example of a molded state of a silver electrode according to the present invention, and FIG. 2 shows an example in which a hydrogen peroxide electrode was constructed using the silver electrode shown in FIG. 1. A partial cross-sectional view, Figure 3 is a characteristic curve diagram showing the response of the hydrogen peroxide electrode shown in Figure 2, and Figure 4 is a diagram showing the response of the hydrogen peroxide electrode shown in Figure 2 and a conventional hydrogen peroxide electrode. Figure 5 is a characteristic curve diagram comparing the linearity between the hydrogen peroxide electrode shown in Figure 2 and a conventional hydrogen peroxide electrode, and Figure 6 is a characteristic curve diagram showing the difference in portangrams at different times. FIG. 3 is a characteristic curve diagram comparing the changes in activity over time between the hydrogen peroxide electrode shown in FIG. 1 and a conventional hydrogen peroxide electrode. 10...Silver electrode, 12.Silver lead wire, 14...Silver-
Silver chloride-silver sulfide-epoxy resin molded body, 16... Through hole, 18... Platinum electrode, 20... Epoxy resin, 22
・Silver lead wire. Sai1 Mouth lε Sai20 θ 30 OtsuOqO Tsuboffl (Pf) Sai3I￥1 ECVvaA7dia) O/L

Claims (1)

【特許請求の範囲】 １）銀粉末と、この銀粉末に対して重量で０．５〜１０
％添加された塩化銀と硫化銀からなる混合物と、前記３
成分を含む混合物に対して重量で０．５〜５％のエポキ
シ樹脂とを混合、攪拌し、加圧成形してなることを特徴
とする酵素電極用銀電極。 ２）特許請求の範囲第一項記載の酵素電極用銀電極にお
いて、塩化銀と硫化銀とから成る混合物中の塩化銀の重
量が１０〜９０％であり、かつ加圧成形が０．３〜１．
５ｔｏｎ／ｃｍ＾２であることを特徴とする酵素電極用
銀電極。[Claims] 1) Silver powder and 0.5 to 10% by weight of this silver powder.
% of silver chloride and silver sulfide;
A silver electrode for an enzyme electrode, characterized in that it is formed by mixing 0.5 to 5% by weight of an epoxy resin with respect to a mixture containing the components, stirring the mixture, and press-molding the mixture. 2) In the silver electrode for an enzyme electrode according to claim 1, the weight of silver chloride in the mixture consisting of silver chloride and silver sulfide is 10 to 90%, and the pressure forming is 0.3 to 90%. 1.
A silver electrode for an enzyme electrode, characterized in that it has a density of 5 ton/cm^2.