JPS60249046A - Method for measuring ion activity - Google Patents

Method for measuring ion activity

Info

Publication number
JPS60249046A
JPS60249046A JP59106006A JP10600684A JPS60249046A JP S60249046 A JPS60249046 A JP S60249046A JP 59106006 A JP59106006 A JP 59106006A JP 10600684 A JP10600684 A JP 10600684A JP S60249046 A JPS60249046 A JP S60249046A
Authority
JP
Japan
Prior art keywords
ion
activity
drain
source
lead wire
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
Application number
JP59106006A
Other languages
Japanese (ja)
Inventor
Shinichi Wakita
慎一 脇田
Kazuo Hiiro
日色　和夫
Takashi Tanaka
孝 田中
Akinobu Kawahara
川原　昭宣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Institute of Advanced Industrial Science and Technology AIST
Original Assignee
Agency of Industrial Science and Technology
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Agency of Industrial Science and Technology filed Critical Agency of Industrial Science and Technology
Priority to JP59106006A priority Critical patent/JPS60249046A/en
Publication of JPS60249046A publication Critical patent/JPS60249046A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/414—Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS

Abstract

PURPOSE:To measure ion activity with a simple circuit by utilizing the interrelation between the square root of drain current and the logarithm of the ion activity when a constant voltage is applied between the source and drain of an ion-selective FET. CONSTITUTION:The ion sensor using the ion-selective FET consists of a glass tube 1, a base body 2, an adhesive agent 3, an ion-sensitive film 4, an FET5, a soldered juncture 6, a gate lead wire 7, a source lead wire 8 and a drain lead wire 9. The sensor is immersed in a soln. contg. the intended ion and the drain current IDS when the specified voltage is applied between the source and drain is measured. The following relation holds between the IDS and the ion activity (a): IDS<1/2>=(Cs(C2+ or -RTlna/nF), where R is gas constant, T is the absolute temp., n is the valency of the intended ion, F is Faraday constant, C2, C3 are constants, a positive code in the case of cation and negative cod in the case of anion. The activity of the intended ion is measured when the C2 and C3 are preliminarily determined by using a soln. having the known ion activity.

Description

【発明の詳細な説明】 本発明は、イオン選択性電界効果トランジスタ（以下ｌ
５ＦＥＴという）を用いたイオン活量測定方法に関する
ものである。本発明紘、各種のイオン活量を測定する方
法として有効に利用できる。DETAILED DESCRIPTION OF THE INVENTION The present invention provides an ion-selective field effect transistor (hereinafter referred to as l).
The present invention relates to a method for measuring ion activity using a 5FET. The present invention can be effectively used as a method for measuring various ion activities.

ｌ５ＦＥＴは、ソース及びドレイン間に流れるドレイン
電流を、イオン感応膜で生じた膜電位によ石ＷＢ効果に
より、制御すゐことを利用したイオンセンサである。The 15FET is an ion sensor that utilizes the fact that the drain current flowing between the source and drain is controlled by the stone WB effect based on the membrane potential generated in the ion-sensitive membrane.

仁のようなｌ５ＦＥＴは、イオン活量測定用センサとし
て用いた場合に、絶縁膜を通して界面電位変化を検出す
るため、感応膜の膜抵抗は問題にならず、また出力イン
ピーダンスも低くなるという優れた特長を有し、このた
め超小型センサーとして適したものである。When used as a sensor for measuring ion activity, 15FETs such as Jin's have the advantage of detecting changes in interfacial potential through an insulating film, so the membrane resistance of the sensitive film does not become a problem, and the output impedance is also low. This makes it suitable as an ultra-small sensor.

仁のｌ５ＦＥＴを用いたイオン活魚測定方法としては、
従来は、ンーヌホｐワー回路とよばれる回路によシ、ソ
ース・ドレイン間に定電流・定電圧を与えた場合のゲー
ト−ソース間の電圧を測定し、これとイオン活量との関
係をめるという方法が行われていた。しかしこのような
方法では、ソース・ドレイン間に定電流・定電圧を与え
るための電源が必要であり、また回路も複雑となる。The ion live fish measurement method using Jin's 15FET is as follows:
Conventionally, the voltage between the gate and the source was measured when a constant current and constant voltage were applied between the source and the drain using a circuit called a Nhoper circuit, and the relationship between this and the ion activity was estimated. The method used was to However, such a method requires a power source to apply a constant current and constant voltage between the source and drain, and the circuit is also complicated.

発明の目的及び構成 本発明者は、ｌ５ＦＥＴを用いたイオン活魚測定におい
て、簡単な回路によシ、各種イオン活量を測定すること
を目的として研究した結果、本発明を完成するに至った
。Purpose and Structure of the Invention The present inventor completed the present invention as a result of research aimed at measuring various ion activities using a simple circuit in ion live fish measurement using a 15FET.

即ち、本発明は、イオン選択性電界効果トランジスタを
使用し、ソース−ドレイン間に定電圧を与えた場合のイ
オン活量の対数とドレイン電流の平方根との間の相関関
係を利用することを特徴とするイオン活量測定方法に係
るものである。That is, the present invention is characterized by using an ion-selective field effect transistor and utilizing the correlation between the logarithm of the ion activity and the square root of the drain current when a constant voltage is applied between the source and the drain. This relates to a method for measuring ion activity.

本発明によれば、イオン活量の測定は、従来のように複
雑な回路を必要とすることなく、ｌ５ＦＥＴを用いたイ
オンセンサを測定対象のイオンを含む溶液中に浸漬させ
、ソース・ドレイン間に一定電圧を与えた時の、ドレイ
ン電流の平方根をめるという簡単な方法により行うこと
ができる。この場合ドレイン電流の平方根は、イオン活
量の対数と一次関係を有するのでこの関係を利用してイ
オン活量をめることが出来る。このドレイン電流の平方
根とイオン活魚の対数の一次関係は本発明者により初め
て明らかＫなった関係である。また本方法の測定回路位
非常に簡単な回路のため、信頼性が高く、かつ種々の装
置を付加することが容易である。According to the present invention, the ion activity can be measured by immersing an ion sensor using an 15FET in a solution containing the ions to be measured, without requiring a complicated circuit as in the past. This can be done simply by taking the square root of the drain current when a constant voltage is applied to the . In this case, since the square root of the drain current has a linear relationship with the logarithm of the ion activity, the ion activity can be determined using this relationship. This linear relationship between the square root of the drain current and the logarithm of the ion live fish is a relationship that was clarified for the first time by the present inventor. Furthermore, since the measuring circuit of this method is a very simple circuit, it is highly reliable and it is easy to add various devices.

本発明によりイオン活量をめることが出来る理由を以下
に説明する。The reason why the ionic activity can be increased by the present invention will be explained below.

電界効果トランジスタ（ＦＥＴ）のソース−ドレイン間
に定電圧を与えた場合のゲート拳ソース間電圧（Ｙｅｓ
）とドレイン電流（Ｉｏｔｔ）の関係は次式により与え
られる。Gate-source voltage (Yes) when a constant voltage is applied between the source and drain of a field effect transistor (FET)
) and the drain current (Iott) is given by the following equation.

１０１　＝　ＣＩ　（ＶＧＩ　−Ｖｒ　）２−−”　（
１）ここで０１はＦＥＴの種類により決まる定数であり
、ＶＴはスレッシュホルド電圧であり、ＦＥＴＫより決
まる定数である。101 = CI (VGI -Vr)2--" (
1) Here, 01 is a constant determined by the type of FET, and VT is a threshold voltage, which is a constant determined by FETK.

ｌ５ＦＥＴの場合にｔｉ、（１）式のＶｏｗに対応する
電位としては、比較電極に与えた電位Ｖ、比較電極の電
位Ｅｒｅｆｓ及びイオン感応膜により生じた膜電位Ｅの
和となる。したがってｌ５ＦＥＴのゲート・ソース電位
（Ｖ＾）は次式のようになる。In the case of a 15FET, the potential corresponding to ti and Vow in equation (1) is the sum of the potential V applied to the comparison electrode, the potential Erefs of the comparison electrode, and the membrane potential E generated by the ion-sensitive membrane. Therefore, the gate-source potential (V^) of the 15FET is expressed by the following equation.

Ｗａｓ　＝　Ｖ　＋　Ｅｒｅｆ　＋　Ｅ　−・・・・”
　（２）よって（１）　、　（２ン式より １ｏｓ＝Ｃｘ（Ｖ＋Ｅｒｅｆ＋Ｅ−Ｖｔ）”　＝　（３
）となる。ここで膜電位Ｅとしてネルンスト電位を仮定
すると Ｔ Ｅ　＝　Ｅ”±−１□８・・・・・・・・・（４）Ｆ となる。こζでＥｏは標準電極電位、Ｒは気体定数Ｔは
絶対温度、ｎは目的イオンの価数、Ｆは７アラデイ定数
、ａは目的イオンの活量であシ、イオンが陽イオンの時
に符号は正であわ、陰イオンのときに負である。（ａ）
　、　（４）式゛よシ１ｏｉ＋　＝　ＣＩ　（Ｃ２土″
−１ｎａ　）２・・・・・・・・・（５）Ｆ 即ち、 Ｔ Ｊｉｎｓ　＝　ＣＢ　（Ｃ２土−：Ｌｈａ　）　＝−・
（６）Ｆ となる。ただしＣ９、ｃ、、は定数である。Was = V + Eref + E -..."
(2) Therefore, (1), (1os=Cx(V+Eref+E-Vt)" = (3
). Here, assuming the Nernst potential as the membrane potential E, T E = E"±-1□8... (4) F. Here, Eo is the standard electrode potential and R is the gas constant. T is the absolute temperature, n is the valence of the target ion, F is the 7 Alladay constant, a is the activity of the target ion, and the sign is positive when the ion is a cation and negative when it is an anion. (a)
, (4) Formula ゛Yoshi1oi+ = CI (C2 soil''
-1na)2・・・・・・・・・(5)F That is, T Jins = CB (C2 Sat-:Lha) =-・
(6) F. However, C9,c, is a constant.

よって（６）式よｌ＋、ｌｏｇの平方根とイオン活魚の
対数とが一次関係にあることがわかる。Therefore, according to equation (6), it can be seen that there is a linear relationship between the square root of l+log and the logarithm of ion live fish.

た上記（６）式の関係を用いるものであり、ｌ５ＦＥＴ
を用いたセンサーを目的イオンを含む溶液中に浸漬し、
ソース・ドレイン間に一定電圧を与えた時のドレイン電
流を測定し、その平方根をめることによってイオン活魚
をめるという方法である。The relationship of equation (6) above is used, and 15FET
The sensor is immersed in a solution containing the target ion,
This method measures the drain current when a constant voltage is applied between the source and drain, and calculates the ion live fish by taking the square root of the value.

即ち、まず目的イオンについて２種以上の既知のイオン
活量の溶液についてＩｏａを測定し、ｌｏｇの平方根と
イオン活魚の対数との間の一次関係をめておく。次いで
、測定溶液についてＩＤ８を測定し、上記の一次関係を
利用し、ＩＤＩ！の平方根より、イオン活魚をめること
ができる。また、この場合、ｆｏｅの平方根とイオン活
魚の対数の間の一次関係を利用するので、対数目盛と平
方根目盛で目盛りたグラフ用紙を使用することＫよシ、
簡単にこの関係を利用することがでらる。That is, first, Ioa is measured for a solution of two or more known ion activities of the target ion, and a linear relationship between the square root of the log and the logarithm of the ion live fish is determined. Next, ID8 is measured for the measurement solution, and using the above linear relationship, IDI! From the square root of , you can get ion live fish. Also, in this case, since the linear relationship between the square root of foe and the logarithm of the ion live fish is used, it is better to use graph paper with a logarithmic scale and a square root scale.
You can easily take advantage of this relationship.

本発明に用いるｌ５ＦＥＴとしては特に制限はなく、現
在公知のｌ５ＦＥＴはすべて使用することが一′Ｐ極真
相怜ｒ？−■騰にＶレイン雷焙か油１史ナスことが可能
である。There are no particular restrictions on the 15FET used in the present invention, and all currently known 15FETs can be used. - ■ It is possible to use V-Rain thunder roasted oil 1 history eggplant in Teng.

このようなｌ５ＦＥＴを使用したセンサとしては各種の
ものが知られているが、その−例を第１図に示す。Various types of sensors using such 15FETs are known, and an example thereof is shown in FIG.

本発明において、ソース・ドレイン間ｉｃ一定［圧を与
えるためには、通常の直流定電圧装置が、すべて有効に
使用でき、乾電池のような簡単なものを使用しても充分
な精度で測定が可能である。In the present invention, all normal DC voltage regulators can be effectively used to apply a constant IC voltage between the source and drain, and even a simple device such as a dry battery can be used to measure with sufficient accuracy. It is possible.

また本発明において使用する電流計としては特に制限は
なく通常の電流針を使用できる。Further, the ammeter used in the present invention is not particularly limited, and a normal current needle can be used.

発明の効果 本発明測定方法は、簡単な回路により、イオン活量の測
定を行うことができ、従来方法と比較しても信頼性が高
く、かつ各種の装置を賽品に付加できるため、イオン活
量測定方法として有効に実施できる。Effects of the Invention The measuring method of the present invention can measure ion activity using a simple circuit, is highly reliable compared to conventional methods, and can be equipped with various devices. It can be effectively implemented as a method for measuring activity.

実施例 以下に実施例を示して本発明を更に詳しく説明する。Example The present invention will be explained in more detail with reference to Examples below.

実施例１゜ 市販のＦＥＴ　（２８に２４１　、東京芝浦電気■製）
のゲートリード部に、カリウムイオン感応物質としての
パリノマイシン５　ｍ　ｌ　、漆６ｏｏｍｙ及びジオク
チルフタレー）４００ｔａｐからなる混合物を塗布し、
温度８０°Ｃ１相対湿度８０チの条件で１０日間、乾燥
硬化させたｌ５ＦＥＴを使用して、以下の条件で測定を
行った。Example 1 Commercially available FET (28 to 241, manufactured by Tokyo Shibaura Electric ■)
Apply a mixture consisting of 5 ml of palinomycin as a potassium ion sensitive substance, 6 oomy lacquer and 400 taps of dioctyl phthalate to the gate lead part of the
Measurements were carried out under the following conditions using a 15FET that had been dried and cured for 10 days at a temperature of 80°C and a relative humidity of 80°C.

測定装置としては、ｌ５ＦＥＴのドレイン・ソース間電
圧（ＶＢ２　）電源には、高砂製作所製ＧＰＴ−８２２
を使用し、ドレイン電流（ＩＤＩＩ）の測定には、北斗
電工社製８Ｍ−１０２型無抵抗電流針を使用した。As a measurement device, GPT-822 manufactured by Takasago Seisakusho is used as the drain-source voltage (VB2) power source of the 15FET.
A non-resistance current needle 8M-102 manufactured by Hokuto Denko Co., Ltd. was used to measure the drain current (IDII).

測定対象溶液は塩化カリウム水溶液を用い、Ｖｏｓ　＝
　８　Ｖとし液ｍ２６℃で撹拌下、１０８を測定した。The solution to be measured is a potassium chloride aqueous solution, and Vos =
108 was measured at 8 V and stirring at 26°C.

第２図にカリウムイオンの活量の対数とドレイン電流の
平方根を目盛りたグラフ用紙を用いたカリウムイオン活
量とドレイン電流との関係を示す。この図からｌ８ＦＦ
ｉ’Ｉ’のドレイン電流の平方根をめることによりカリ
ウムイオン活量をめることができることがわかる。FIG. 2 shows the relationship between potassium ion activity and drain current using a graph paper scaled with the logarithm of potassium ion activity and the square root of drain current. From this figure, l8FF
It can be seen that the potassium ion activity can be calculated by taking the square root of the drain current of i'I'.

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

第１図は、ｌ８ＦＥｔ’ｆ’を用いたイオンセンサの一
例である。図中、（１）はガヲヌ管、（２）は基体、（
３）は接着剤、（４）はイオン感応膜、（５）はＦｌ！
ＩＴ、（６）はノーンダ付接続部分、（７）はゲートリ
ード線、（８）はソースリード線、（９）はドレインリ
ード線を示す。 第２図はカリウムイオン活量の対数とドレイン電流の平
方根との関係を示すグラフである。 （以　上） 第１図 第２図 力リワムイ＾＞ｅ右葉の対叛FIG. 1 is an example of an ion sensor using 18FEt'f'. In the figure, (1) is the Gaonu tube, (2) is the base, (
3) is an adhesive, (4) is an ion-sensitive membrane, and (5) is Fl!
IT, (6) shows a connection part with solder, (7) shows a gate lead wire, (8) shows a source lead wire, and (9) shows a drain lead wire. FIG. 2 is a graph showing the relationship between the logarithm of potassium ion activity and the square root of drain current. (That's all) Figure 1 Figure 2 Rikiwamuyi^>e Rebellion of the right lobe

Claims (1)

【特許請求の範囲】[Claims] ■　イオン選択性電界効果トランジスタを使用し、ソー
ス・ドレイン間に定電圧を与えた場合の、イオン活魚の
対数とドレイン電流の平方根との間の相関関係を利用す
ることを特徴とするイオン活魚測定方法。■ Live ion fish measurement using an ion selective field effect transistor and utilizing the correlation between the logarithm of the ion live fish and the square root of the drain current when a constant voltage is applied between the source and drain. Method.
JP59106006A 1984-05-24 1984-05-24 Method for measuring ion activity Pending JPS60249046A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59106006A JPS60249046A (en) 1984-05-24 1984-05-24 Method for measuring ion activity

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59106006A JPS60249046A (en) 1984-05-24 1984-05-24 Method for measuring ion activity

Publications (1)

Publication Number Publication Date
JPS60249046A true JPS60249046A (en) 1985-12-09

Family

ID=14422592

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59106006A Pending JPS60249046A (en) 1984-05-24 1984-05-24 Method for measuring ion activity

Country Status (1)

Country Link
JP (1) JPS60249046A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5793247A (en) * 1980-11-29 1982-06-10 Shimadzu Corp Ion measuring device
JPS5824851A (en) * 1981-05-15 1983-02-14 リツエンツイア・パテント−フエルヴアルツンダス−ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング Method and device for measuring ion concentration

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5793247A (en) * 1980-11-29 1982-06-10 Shimadzu Corp Ion measuring device
JPS5824851A (en) * 1981-05-15 1983-02-14 リツエンツイア・パテント−フエルヴアルツンダス−ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング Method and device for measuring ion concentration

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