JPH0337558A - Method and apparatus for measuring conductivity and method for measuring concentration - Google Patents
Method and apparatus for measuring conductivity and method for measuring concentrationInfo
- Publication number
- JPH0337558A JPH0337558A JP17156689A JP17156689A JPH0337558A JP H0337558 A JPH0337558 A JP H0337558A JP 17156689 A JP17156689 A JP 17156689A JP 17156689 A JP17156689 A JP 17156689A JP H0337558 A JPH0337558 A JP H0337558A
- Authority
- JP
- Japan
- Prior art keywords
- measuring
- measured
- applied voltage
- concentration
- conductivity
- 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.)
- Granted
Links
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- 238000004448 titration Methods 0.000 description 20
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- 239000011780 sodium chloride Substances 0.000 description 11
- 238000006386 neutralization reaction Methods 0.000 description 10
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 7
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 description 7
- 238000011088 calibration curve Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
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- 235000011152 sodium sulphate Nutrition 0.000 description 7
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- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000000693 micelle Substances 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
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- 239000000126 substance Substances 0.000 description 4
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 description 3
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 3
- 229910052776 Thorium Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- BTURAGWYSMTVOW-UHFFFAOYSA-M sodium dodecanoate Chemical compound [Na+].CCCCCCCCCCCC([O-])=O BTURAGWYSMTVOW-UHFFFAOYSA-M 0.000 description 3
- 229940082004 sodium laurate Drugs 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
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- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- SFKTYEXKZXBQRQ-UHFFFAOYSA-J thorium(4+);tetrahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[Th+4] SFKTYEXKZXBQRQ-UHFFFAOYSA-J 0.000 description 2
- IPIGTJPBWJEROO-UHFFFAOYSA-B thorium(4+);tetraphosphate Chemical compound [Th+4].[Th+4].[Th+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O IPIGTJPBWJEROO-UHFFFAOYSA-B 0.000 description 2
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- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
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- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 1
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- JUQGWKYSEXPRGL-UHFFFAOYSA-M sodium;tetradecanoate Chemical compound [Na+].CCCCCCCCCCCCCC([O-])=O JUQGWKYSEXPRGL-UHFFFAOYSA-M 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
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Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、電導度の測定方法および装置、ならびに濃
度の測定方法に関し、詳しくは、各種の塩ｌ客演等に対
して、濃度を測定したり、臨界くセル濃度を決定したり
するために、これら溶液の電導度を測定する方法、およ
び、この測定方法に用いる測定装置、ならびに、被測定
波中の特定成分の濃度を測定する方法に関するものであ
る。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for measuring conductivity, and a method for measuring concentration. The present invention relates to a method for measuring the conductivity of these solutions in order to determine the critical cell concentration, a measuring device used in this measuring method, and a method for measuring the concentration of a specific component in a wave to be measured. It is something.
従来、電導度の測定には、ホイートストンブリ、ッジを
利用した測定方法および装置が採用されていた。Conventionally, a measuring method and apparatus using a Wheatstone bridge have been used to measure conductivity.
第１２図は、ホイートストンブリソジを利用した従来の
電導度測定装置の概略構成を示しており、測定電極を収
容し、被測定液に投入される測定セルＣと、基準抵抗Ｒ
１可変抵抗部ａ −ｃ 、電流検出器りでポイートスト
ンブリノジ回路を構成しており、交流電源Ｉを可変抵抗
部ａ −ｃの任意の途中点Ｘに接触させて印加し、この
接触点を左右に移動させながら、両端ａ、ｂ間に挿入さ
れた電流検出器りで電流を検出し、ａ−ｂ間の電流が０
になったときの点Ｘの位置から、ａ−ｘ間の抵抗および
ｘ−ｂ間の抵抗を求め、これらの抵抗値と基準抵抗Ｒの
抵抗値から測定セルＣの抵抗値を求める。測定セルＣの
抵抗値が判れば、測定セルＣの抵抗値は被測定液の電導
度に反比例するので、抵抗値から電導度が算出できると
いうものであるなお、被測定液に含まれる塩類等の成分
の濃度は、これらの含有成分が電解質であれば、被測定
液の電導度に比例するので、被測定液の電導度から含有
成分の濃度を測定することも可能になるのである。FIG. 12 shows a schematic configuration of a conventional conductivity measuring device using a Wheatstone bridge, which includes a measuring cell C that accommodates a measuring electrode and is introduced into a liquid to be measured, and a reference resistance R.
1 Variable resistance parts a - c and a current detector constitute a point-to-point bridge circuit, and an AC power supply I is applied by contacting an arbitrary point X of variable resistance parts a - c, and this contact point While moving left and right, the current is detected with a current detector inserted between both ends a and b, and the current between a and b is 0.
The resistance between a and x and the resistance between x and b are determined from the position of point X when If the resistance value of measurement cell C is known, the resistance value of measurement cell C is inversely proportional to the conductivity of the liquid to be measured, so the conductivity can be calculated from the resistance value. If these components are electrolytes, the concentration of the components is proportional to the conductivity of the liquid to be measured, so it is also possible to measure the concentration of the components from the conductivity of the liquid to be measured.
ところが、上記のような従来のホイー１〜ストンフリン
ジを利用した電導度測定装置は、ホイートス（・ンブリ
ソジ等の複雑な電気回路を必要とし、測定装置の構造が
複雑でコス１〜が高くつくという欠点があった。However, the conventional conductivity measuring device using the stone fringe as described above requires a complicated electric circuit such as a whetstone, and the structure of the measuring device is complicated and the cost is high. There were drawbacks.
また、前記したホイートストンブリソジ回路の構光では
、電流検出器りに流れる電流が０になるように交流電源
Ｉの接続点Ｘを左右に移動調整するか、電流検出器りの
表示や発振音を監視しながら接続点Ｘを左右に細かく調
整する面倒な操作が必要であった。In addition, in the configuration of the Wheatstone Brissage circuit described above, it is necessary to adjust the connection point A troublesome operation was required to finely adjust the connection point X left and right while monitoring the sound.
さらに、従来の電導度測定装置を濃度測定に使用した場
合、濃度が低い範囲では充分な精度が得られるが、濃度
が高くなると誤差が大きくなるという欠点もあった。Furthermore, when a conventional conductivity measuring device is used for concentration measurement, sufficient accuracy can be obtained in a low concentration range, but there is also the drawback that the error increases as the concentration increases.
そこで、この発明の課題は、前記した従来の電導度の測
定方法および装置の問題点を解消し、簡単かつ正確に電
導度が測定できる測定方法、および、上記測定方法を実
施できる簡単な構造の測定装置を提（」（することにあ
る。また、上記のような電導度の測定方法および装置を
利用して、被測定溶液中の含有成分の濃度を簡単かつ正
確に測定する方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring method that can easily and accurately measure conductivity by solving the problems of the conventional conductivity measuring method and device described above, and a simple structure that can carry out the above measuring method. The present invention also provides a method for easily and accurately measuring the concentration of components in a solution to be measured by using the conductivity measuring method and device as described above. There is a particular thing.
上記副題を解決する、この発明のうち、請求項１記載の
電導度の測定方法は、被測定液に投入された一対の測定
電極間に電圧を印加し、測定電極間を流れる電流値が所
定の電流値になるように印加電圧を変化させ、このとき
の印加電圧値に基づいて被測定液の電導度を算出するよ
うにしているすなわち、従来のホイートストンブリソジ
回路を利用した電導度の測定方法が、測定電極間の抵抗
を直接測定するようにしているのに対し、この発明では
、印加電圧から電導度を測定するようにしているのであ
る。測定電極間を流れる電流値を一定にしたときの、印
加電圧と電導度との相関関係は、測定電極の構造や測定
条件等によって違うので、予め、電導度が既知の被測定
液に対して、印加電圧と電導度の相関関係を乃（す定し
ておき、電導度が未知の被測定液について測定した印加
電圧の値を、前記相関関係に当てはめることによって、
電導度が算出できる。A method for measuring electrical conductivity according to claim 1 of the present invention that solves the above sub-problem applies a voltage between a pair of measurement electrodes introduced into a liquid to be measured, and a current value flowing between the measurement electrodes is set to a predetermined value. The applied voltage is changed so that the current value becomes , and the conductivity of the liquid to be measured is calculated based on the applied voltage value. While the measurement method directly measures the resistance between the measurement electrodes, the present invention measures the conductivity from the applied voltage. The correlation between the applied voltage and conductivity when the current value flowing between the measurement electrodes is held constant varies depending on the structure of the measurement electrodes and measurement conditions. , by predetermining the correlation between applied voltage and electrical conductivity, and applying the value of the applied voltage measured for a liquid to be measured whose electrical conductivity is unknown to the correlation,
Conductivity can be calculated.
この発明の測定方法は、従来の電導度測定方法が採用さ
れている各種の用途に利用でき、具体的には、例えば、
各種工業分野や農業分野における水質管理等が挙げられ
る。また、理科や化学の教育実験用の測定方法としても
有用であり、例えば、中和滴定や沈澱滴定等が簡単に行
える。The measuring method of the present invention can be used in various applications where conventional conductivity measuring methods are employed, and specifically, for example,
Examples include water quality management in various industrial and agricultural fields. It is also useful as a measurement method for educational experiments in science and chemistry, and for example, neutralization titration, precipitation titration, etc. can be easily performed.
請求項２記載の電気型導度の測定装置は、被測定液に投
入される一対の測定電極と、測定電極間に電圧を印加す
る電圧印加手段と、測定電極間に流れる電流値を検出す
る電流検出手段と、電流検出手段で検出される電流値が
特定の値になるよ・）に印加電圧を変化させる印加電圧
変更手段と、印加電圧値を検出する印加電圧検出手段と
からなるものである。The electrical conductivity measuring device according to claim 2 includes a pair of measuring electrodes introduced into a liquid to be measured, a voltage applying means for applying a voltage between the measuring electrodes, and a current value flowing between the measuring electrodes. It consists of a current detecting means, an applied voltage changing means for changing the applied voltage so that the current value detected by the current detecting means becomes a specific value, and an applied voltage detecting means for detecting the applied voltage value. be.
測定電極としては、通常の電導度測定における電極と同
様の構造で実施できる。従来、−数的に使用されている
白金電極は、被測定波中のイオンと電極の反応を考慮し
なくてもよい点では好ましい。しかし、測定精度や感度
を向上させるには、測定電極の表面積を増やしたり形状
を工夫する必要があるが、前記した白金は高価であるた
め、大型化や加工が難しい。そこで、ステンレス専の比
較的安価で加工し易い材料からなるものを用いて、測定
電極の表面積を増大させたもののほうが実用的である。The measurement electrode can have a structure similar to that of an electrode used in ordinary conductivity measurement. Platinum electrodes, which have conventionally been used numerically, are preferable in that there is no need to take into account the reaction between the ions in the wave to be measured and the electrodes. However, in order to improve measurement accuracy and sensitivity, it is necessary to increase the surface area of the measurement electrode or to devise a shape, but since platinum is expensive, it is difficult to increase the size and process it. Therefore, it is more practical to increase the surface area of the measurement electrode by using a material made of stainless steel, which is relatively inexpensive and easy to process.
測定電極の形状は、線状、棒状、パイプ状、板状、網状
等、任意の形状で実施できる。一対の測定電極は、適当
な保持手段によって、所定の間隔をあけた状態で固定さ
れる。The shape of the measurement electrode can be any shape such as a line, rod, pipe, plate, or net. The pair of measurement electrodes are fixed at a predetermined distance by appropriate holding means.
測定電極は、従来の電導度計のように、ガラス等からな
る測定セルに収容された状態で、この測定セルに被測定
／夜を流通させるようにしてもよいし、一対の測定電極
を組み込んだＷｉｌｌ定棒もしくは測定ユニソトを、被
測定液の容器等に浸けるようにしてもよい。The measuring electrodes may be housed in a measuring cell made of glass or the like, as in a conventional conductivity meter, and the sample/night may be passed through the measuring cell, or a pair of measuring electrodes may be incorporated. It is also possible to immerse the Will constant rod or measuring unit into a container of the liquid to be measured.
測定電極間への電圧印加手段は、通常の商用交流電源あ
るいは各種の充電式電源等がそのまま利用でき、電圧の
周波数は必要に応して適宜に設定される。As the means for applying voltage between the measurement electrodes, a normal commercial AC power supply or various rechargeable power supplies can be used as is, and the frequency of the voltage is appropriately set as necessary.
電流検出手段は、測定電極間を流れる電流値を検出−（
きれば、各種の計測装置に採用されている電疏計等が使
用でき、電流値を指針や数値で表示するもの等、電流値
の表示手段は任意の構成で実施できる。The current detection means detects the value of the current flowing between the measurement electrodes.
If possible, an electric wire meter or the like employed in various measuring devices can be used, and the current value display means can be implemented in any configuration, such as one that displays the current value with a pointer or numerical value.
印加電圧変更手段は、前記電圧印加手段で被測定電極間
に印加される電圧を変更できればよ（、通常の計測装置
で用いられている各種の変圧器等が利用できる。印加電
圧変更手段の操作は、前記電流検出手段で検出された測
定電極間の電流値を読め取って、電流値が所定の値にな
るように手動で操作するようになっていてもよいし、検
出された電流値を電気的に処理して、印加電圧変更手段
を電気的に制御するように構成することもできる印加電
圧検出手段は、測定電極間に印加される電圧を検出する
ものであり、検出された印加電圧から電導度が算出され
る。具体的な印加電圧検出手段としては、通常の計測装
置で用いられている電圧計等が利用できる。印加電圧検
出手段では、検出された印加電圧の値をそのまま表示し
、表示された電圧値を測定者が読め取って電導度や濃度
に換算するようにしてもよいが、検出された印加電圧を
もとにして、電気的に演算処理して、電導度や濃度に換
算する演算手段を備えていたり、印加電圧あるいは演算
された電導度や濃度等を記録する記録手段を備えていて
もよい。The applied voltage changing means may be any voltage applying means as long as it can change the voltage applied between the electrodes to be measured (various types of transformers used in ordinary measuring devices can be used). may be configured such that the current value between the measurement electrodes detected by the current detection means is read and manually operated so that the current value becomes a predetermined value, or the detected current value is read. The applied voltage detecting means, which can be configured to electrically process and electrically control the applied voltage changing means, detects the voltage applied between the measurement electrodes, and the applied voltage detecting means detects the voltage applied between the measurement electrodes. The conductivity is calculated from .The applied voltage detection means can be a voltmeter or the like used in a normal measuring device.The applied voltage detection means displays the value of the detected applied voltage as it is. However, it is also possible for the measurer to read the displayed voltage value and convert it into conductivity or concentration. However, based on the detected applied voltage, electrical calculations can be performed to calculate conductivity or concentration. It may be provided with a calculation means for converting into concentration, or a recording means for recording the applied voltage or the calculated conductivity, concentration, etc.
この発明の測定装置は、前記した請求項１記載の測定力
法と同様に、各種の工業分封、家庭用機器分野、あるい
は教育分野で利用することができる。The measuring device of the present invention can be used in various industrial packaging, household equipment fields, or educational fields, similar to the measuring force method described above.
請求項３記載の発明にかかる濃度の測定方法は、被測定
液に投入された一対の測定電極間に電圧を印加したとき
、測定電極間を流れる電流値が一定の場合に、印加電圧
と被測定１皮中の特定成分の濃度との間における相関関
係をもとにして、所定の電流値になるように印加電圧を
変化させたときの印加電圧の値から被測定液の特定成分
の濃度を算出するようにしている。In the method for measuring concentration according to the invention described in claim 3, when a voltage is applied between a pair of measurement electrodes introduced into a liquid to be measured, and when the value of the current flowing between the measurement electrodes is constant, the applied voltage and the Measurement 1 Based on the correlation between the concentration of the specific component in the skin, and the applied voltage value when the applied voltage is changed to a predetermined current value, the concentration of the specific component in the liquid to be measured is determined. I am trying to calculate.
印加電圧と被測定液中の特定成分の濃度との相関門係は
、予め、既知の各種濃度の被測定波に対して、測定電極
間に一定値の電流を流すのに必要な印加電圧を測定して
おけばよい。測定電極間の印加電圧と被測定液中の特定
成分の濃度とは、対数関係になる。したがって、印加電
圧と濃度の相関関係を示すグラフすなわち検量線を作製
しておけば、未知の被測定波に対して印加電圧を測定す
るだりで、目的とする特定成分の濃度を算出することが
できる。また、上記した、印加電圧と特定成分の濃度の
相関関係を、電子的な回路や演算回路に組み込んでおけ
ば、濃度の算出を自動的に行うこともできる。The correlation between the applied voltage and the concentration of a specific component in the measured liquid is determined in advance by determining the applied voltage necessary to cause a constant value of current to flow between the measuring electrodes for the measured waves of various known concentrations. Just measure it. The voltage applied between the measurement electrodes and the concentration of the specific component in the liquid to be measured have a logarithmic relationship. Therefore, if you create a graph showing the correlation between applied voltage and concentration, that is, a calibration curve, you can calculate the concentration of a specific component by measuring the applied voltage for an unknown measurement wave. can. Further, if the above-mentioned correlation between the applied voltage and the concentration of the specific component is incorporated into an electronic circuit or an arithmetic circuit, the concentration can be calculated automatically.
上記した濃度の測定方法が通用できる成分としては、塩
化ナトリウム、フソ化ナトリウム、硫酸ナトリウム、リ
ン酸ナトリウム等の塩類、ドデシル硫酸ナトリウム（Ｓ
ＤＳ） 、Ｆデシルベンゼンスルホン酸ナトリウム（Ｄ
ＢＳ）、ラウリン酸ナトリウム、くリスチン酸すトリウ
ム笠の陰イオン界面活性剤、その他任意の電解質成分に
対して適用できる。Components for which the concentration measurement method described above can be applied include salts such as sodium chloride, sodium fusodide, sodium sulfate, and sodium phosphate, and sodium dodecyl sulfate (S
DS), Sodium F-decylbenzenesulfonate (D
It can be applied to anionic surfactants such as BS), sodium laurate, thorium chlorinate, and any other electrolyte components.
０
また、電解質成分でなくても、電解質との共’１７下で
は、濃度の変化に伴って電導度が変化するような成分で
あれば、測定可能である。このような成分の具体例とし
ては、ノニオン界面活性剤であるアルキルポリオキシエ
チレンコニ−チル）等が挙げられる。0 In addition, even if it is not an electrolyte component, it is possible to measure any component whose conductivity changes with a change in concentration in the presence of an electrolyte. Specific examples of such components include alkyl polyoxyethylene conythyl, which is a nonionic surfactant.
一対の測定電極間に印加される電圧Ｖと、電流Ｉおよび
抵抗Ｒの間には、Ｖ＝ｌＲの関係があるのて、電流Ｉが
一定であれば、電圧Ｖは抵抗Ｒに比例する。したがって
、電導度に直接関係のある抵抗Ｒを測定して電導度を求
める代わりに、電圧Ｖを測定しても電導度を求めること
ができるのである。すなわち、測定電極間を流れる電流
か一定であれば、印加電圧と電導度には１対１の相関関
係があるので、この印加電圧と電導度の相関関係を、予
め電導度の判っている被測定ｌ＋ｋについて求めておく
。そして、電導度か未知の被測定液に対して、所定の電
流値になるように印加電圧を変化させたときの印加電圧
の埴を測定して、前記印加電圧と電導度との相関関係に
当てはめれば、印加電圧の測定値から被測定／夜の電導
度を算出することかできるのである。There is a relationship of V=lR between the voltage V applied between the pair of measurement electrodes, the current I and the resistance R, so if the current I is constant, the voltage V is proportional to the resistance R. Therefore, instead of determining the conductivity by measuring the resistance R, which is directly related to the conductivity, the conductivity can also be determined by measuring the voltage V. In other words, if the current flowing between the measurement electrodes is constant, there is a one-to-one correlation between the applied voltage and the conductivity. Calculate the measurement l+k. Then, for a liquid to be measured whose conductivity is unknown, the applied voltage is measured when the applied voltage is changed to a predetermined current value, and the correlation between the applied voltage and the conductivity is determined. By applying this, it is possible to calculate the conductivity of the object to be measured/at night from the measured value of the applied voltage.
請求項２記載の測定装置によれば、上記請求項１記・或
の測定方法を、測定電極、電圧印加手段、電流検出手段
、印加電圧変更手段、印加電圧検出手段の構成により実
施することかできる。測定電極および各手段は、何れも
、通常の測定装置で採用されている一般的な構造部品が
使用できる。According to the measuring device according to claim 2, the certain measuring method according to claim 1 can be carried out by the configuration of the measuring electrode, the voltage applying means, the current detecting means, the applied voltage changing means, and the applied voltage detecting means. can. For both the measuring electrode and each means, general structural parts employed in ordinary measuring devices can be used.
請求項３記載の濃度の測定方法は、被測定液の含有成分
が電解質であれば、被測定／夜の電導度と含を成分の濃
度は比例することから、請求項１記載の測定方法による
電導度の測定を、特定成分の濃度のｉｊｊｌｌ定に適用
したものである。被測定液の特定成分の濃度と電導度す
なわち印加電圧との相関関係は、−予め、濃度が既知の
被測定ｌ夜に幻して測定を行っておけば、未知濃度の被
測定液に対しても、印加電圧を測定するだけで、濃度が
求められる。The concentration measuring method according to claim 3 is based on the method according to claim 1, because if the component contained in the liquid to be measured is an electrolyte, the concentration of the component is proportional to the conductivity of the sample/night. The measurement of electrical conductivity is applied to determine the concentration of a specific component. The correlation between the concentration of a specific component in the liquid to be measured and the conductivity, that is, the applied voltage, is as follows: - If you perform the measurement in advance at night when the concentration is known, it is possible to However, the concentration can be determined simply by measuring the applied voltage.
なお、濃度を測定しようとする特定成分が電解質成分で
なくても、電解質成分と共存させること等で、濃度の変
化に伴って被測定液の電導度が変化するような成分であ
れば、印加電圧と電導度の変化すなわち濃度の変化との
相関関係を求めておくことによって、上記同様に、印加
電圧から濃度を測定することが可能になる。Even if the specific component whose concentration is to be measured is not an electrolyte component, if it is a component that causes the conductivity of the liquid to be measured to change as the concentration changes due to coexistence with the electrolyte component, the applied voltage may be applied. By determining the correlation between the voltage and the change in conductivity, that is, the change in concentration, it becomes possible to measure the concentration from the applied voltage in the same way as described above.
ついで、この発明の実施例を図面を参照しながら以下に
詳しく説明する。Next, embodiments of the present invention will be described in detail below with reference to the drawings.
測定装置の構造
第１図は、この発明の実施に用いる電導度測定装置の概
雌構造を示している。図示した装置し４″、ｌ！ｉ育現
場における捏和や化学の実験で、電導度や濃度について
説明するために用いる教育用の電導度測定装置である。Structure of Measuring Apparatus FIG. 1 shows the general structure of the conductivity measuring apparatus used for carrying out the present invention. The illustrated device 4'' is an educational conductivity measuring device used to explain conductivity and concentration in kneading and chemical experiments at educational sites.
外形６Ｘ６ｃｍの板状をなす一対のステンレス電極１０
．１０を間隔１．６ｃｍの距離で保持した測定電極を使
用し、この測定電極１０．１０を、イオン交換水（２５
°Ｃ、Ｉｆｆ）を収容した容量２１のビーカーからなる
測定容器２０に投入している。A pair of stainless steel electrodes 10 in the form of a plate with an outer diameter of 6 x 6 cm.
．． Using measuring electrodes held at a distance of 1.6 cm, the measuring electrodes 10.10 were placed in ion exchange water (25 cm).
The sample is placed in a measurement container 20 consisting of a beaker with a capacity of 21 containing a temperature (°C, Iff).
３
被測定？＆Ｗの温度を一定に保つために、測定容器２０
を恒温水槽２１に収容している。恒温水槽２１ば攪拌装
置２２（東洋製作新製、Ｄ−２８）の上に載せられ、測
定容器２０の底には攪拌具２３が投入されており、攪拌
装置２２から磁気作用等で攪拌具２３を回転させて、測
定容器２０内の被測定液Ｗを攪拌する。3 Measured? In order to keep the temperature of &W constant, measuring container 20
is housed in a constant temperature water tank 21. The constant temperature water tank 21 is placed on a stirring device 22 (manufactured by Toyo Seisaku Shin, D-28), and a stirring tool 23 is placed in the bottom of the measurement container 20. is rotated to stir the liquid to be measured W in the measurement container 20.
測定電極１０．、１０には、交流電源装置３０（品性製
作所製、ＥＳ−５Ｆ）、豆電球４０（４．８Ｖ用）が直
列に接続されて、測定回路５０を構成している。交流電
源装置３０は、電源コード３１で商用電源に接続され、
測定回路５０への出力電圧を用変できるようになってお
り、出力電圧値を表示する電圧計３２を備えている。豆
電球４０は、測定回路５０を流れる電流値を所定の値に
設定するとともに、電流もしくは印加電圧の変化を視覚
的に捉えるために利用される。Measuring electrode 10. , 10 are connected in series with an AC power supply device 30 (manufactured by Konsei Seisakusho, ES-5F) and a miniature light bulb 40 (for 4.8V), thereby forming a measurement circuit 50. The AC power supply device 30 is connected to a commercial power source with a power cord 31,
The output voltage to the measuring circuit 50 can be changed, and a voltmeter 32 is provided to display the output voltage value. The miniature light bulb 40 is used to set the current value flowing through the measurement circuit 50 to a predetermined value and to visually capture changes in the current or applied voltage.
豆電球４０は、内径５． ５ ｃｍ、長さ１０ｃｍの遮
光性のしニルバイブロ０の一端に装着され、ビニルバイ
ブロ０の他端には太陽型／Ｉ！１１．０ （ＵＢ Ｉ
２ ０４
ＯＡＳ、開放電圧０．５４ Ｖ、短絡電流２２５ ｍＡ
）が装着されている。豆電球４ｏの光を見せるときには
、ビニルパイプ６０を取り外せばよい。また、ビニルバ
イブロ０の一部に開閉自在な扉を設けておき、必要なと
きだけ扉を開くようにしてもよい。太陽電池７０には電
圧計８０ （ＨＩＯＫＩ３２１７ ）が接続されてあり
、豆電球４０の光によって太陽電池７０に発生ずる起電
圧（Ｅｌｅｃｔｏｒｏｍｏｔｉｖｅｆｏｒｃｅ ：以下
ＥＭＦという）を読め取れるようになっている。太陽電
池７０のＥＭＦは、豆電球４０の光量によって変化し、
豆電球４ｏの光量は測定回路５０を流れる電流によって
変化する。したがって、太陽型／ｌ！１７０のＥＭＦを
電圧計８０テ／Ｊｌり定することよって、間接的に測定
回路５ｏを流れる電流が測定できることになるとともに
、その電流の変化を豆電球４０の明るさとして視覚的に
捉えることができる。このことば、教育現場等において
、実験結果を視覚的に理解させることができ、極めて好
ましいものである。The miniature light bulb 40 has an inner diameter of 5. A 5 cm, 10 cm long light shielding plate is attached to one end of the vinyl vibro 0, and the other end of the vinyl vibro 0 has a sun-shaped /I! 11.0 (UB I
2 04 OAS, open circuit voltage 0.54 V, short circuit current 225 mA
) is installed. When displaying the light from the miniature light bulb 4o, the vinyl pipe 60 can be removed. Furthermore, a door that can be opened and closed may be provided in a part of the vinyl vibro 0, and the door may be opened only when necessary. A voltmeter 80 (HIOKI 3217) is connected to the solar cell 70 so that the electromotive force (hereinafter referred to as EMF) generated in the solar cell 70 by the light from the miniature light bulb 40 can be read. The EMF of the solar cell 70 changes depending on the light intensity of the miniature light bulb 40,
The amount of light from the miniature light bulb 4o changes depending on the current flowing through the measurement circuit 50. Therefore, solar type /l! By determining the EMF of 170 with a voltmeter of 80 Te/Jl, the current flowing through the measurement circuit 5o can be indirectly measured, and changes in the current can be visually perceived as the brightness of the miniature light bulb 40. can. This language is extremely preferable in educational settings, etc., as it allows for visual understanding of experimental results.
但し、産業用途に利用する場合には、豆電球４０や太陽
電池７０等を使用せず、測定回路５０の一部に電流値を
検出できる電流計等を装着しておいても、勿論実施可能
である。However, when used for industrial purposes, it is of course possible to install an ammeter or the like that can detect the current value in a part of the measurement circuit 50 without using the miniature light bulb 40 or the solar cell 70. It is.
電導度および濃度の測定
上記のような測定装置を使用して、測定容器２０内に各
種の試料を添加しな、がら、電圧計８０の指示電圧で表
される太陽電池７０のＥＭＦ、すなわち測定回路５０を
流れる電流値と、交流電源装置３（）の印加電圧の関係
を測定することによって、被？ＪｌＩＪ定液の電導度お
よび濃度が測定できることを確認した。Measurement of conductivity and concentration Using the measuring device as described above, while adding various samples into the measurement container 20, measure the EMF of the solar cell 70 represented by the voltage indicated by the voltmeter 80. By measuring the relationship between the current value flowing through the circuit 50 and the applied voltage of the AC power supply device 3 (), It was confirmed that the conductivity and concentration of JlIJ constant solution could be measured.
測定容器２０のイオン交換水に添加する試料として、塩
化ナトリウム、フソ化すトリウム、硫酸ナトリウム、リ
ン酸すトリウム（何れも特級試薬、和光純薬製）を準備
した。また、陰イオン界面活性剤の試料として、ドデシ
ル硫酸ナトリウム（ＳＤＳ、和光純薬製、生化学用）、
Ｆデシルヘンセンスルホン酸すトリウム（ＤＢＳ、和光
純薬製、衣利用合或洗剤試験用）、ラウリン酸ナトリウ
ム、ミリスチン酸ナトリウム（何れも日本油脂製）を精
製せずに使用した。Sodium chloride, thorium fusodide, sodium sulfate, and thorium phosphate (all special grade reagents, manufactured by Wako Pure Chemical Industries, Ltd.) were prepared as samples to be added to the ion-exchanged water in the measurement container 20. In addition, as samples of anionic surfactants, sodium dodecyl sulfate (SDS, manufactured by Wako Pure Chemical Industries, Ltd., for biochemical use),
Thorium F-decylhensensulfonate (DBS, manufactured by Wako Pure Chemical Industries, Ltd., for clothing use combination detergent test), sodium laurate, and sodium myristate (all manufactured by Nippon Oil & Fats) were used without purification.
比較のために、従来のホイートスｌ−ンブリソシ構造を
用いた電導度測定装置（電気化学計器製、ＡＯＬ−１０
）でも同しような測定を行った。For comparison, we used a conductivity measuring device (manufactured by Denki Kagaku Keiki Co., Ltd., AOL-10) using a conventional Wheatstone bridge structure.
), but similar measurements were made.
第２図は、塩化ナトリウムを試料に用い、電圧計８０で
太陽電池７０のＥＭＦを一定にした状態、すなわち豆電
球４０の明るさを一定にし、測定回路５０の電流値を一
定にしたときの、交流電源装置３０の印加電圧■１と試
料の濃度Ｃとの関係をグラフで示している。実験例１．
１は、１．５Ｖの豆電球を用い、ＥＭＦ＝０．３８０Ｖ
になるように設定した。実験例１．２は、４．８Ｖの豆
電球を用い、ＥＭＦ＝０．４５０ Ｖになるように設定
した。このグラフによれば、濃度Ｃの増加に伴って印加
電圧Ｖｌが双曲線を描いて減少しており、印加電圧Ｖｌ
と塩濃度Ｃが相関関係にあることが判る。FIG. 2 shows a state in which sodium chloride is used as a sample and the EMF of the solar cell 70 is kept constant using the voltmeter 80, that is, the brightness of the miniature light bulb 40 is kept constant and the current value of the measuring circuit 50 is kept constant. , a graph showing the relationship between the applied voltage (1) of the AC power supply device 30 and the concentration C of the sample. Experimental example 1.
1 uses a 1.5V miniature light bulb, EMF=0.380V
I set it to be. In Experimental Example 1.2, a 4.8V miniature light bulb was used and the EMF was set to 0.450V. According to this graph, as the concentration C increases, the applied voltage Vl decreases in a hyperbolic manner, and the applied voltage Vl
It can be seen that there is a correlation between C and salt concentration C.
濃度Ｃが無限大の場合の印加電圧（基準電圧）Ｖｏを、
各グラフの漸近線として外挿法で求めるとＯにはならず
、実験例１．１ではＶ、＝１．２／ＩＶ、実験例１．２
ではＶ。−２，０６Ｖであった。した７
かって、測定電極１０間に加わる真の印加電圧■２は、
交流電源装置３０の電圧計３２で測定された印加電圧Ｖ
ｏと前記基準電圧Ｖｏから、下式で表される。The applied voltage (reference voltage) Vo when the concentration C is infinite is
When the asymptote of each graph is obtained by extrapolation, it does not become O, and in Experimental Example 1.1, V, = 1.2/IV, Experimental Example 1.2
So V. -2.06V. 7 The true applied voltage ■2 applied between the measurement electrodes 10 is
Applied voltage V measured by voltmeter 32 of AC power supply device 30
o and the reference voltage Vo, it is expressed by the following formula.
Ｖ２＝ＶＩＶｏ・−・−−・（１１
第３図は、測定電極１０間の印加電圧Ｖ２と濃度Ｃの関
係を対数でプロソトしたものであり、直線で表されてい
ることから、印加電圧Ｖ２と濃度Ｃが対数関係にあるこ
とが判る。実験例１．１および実験例１．２の直線グラ
フの勾配は、実験例１．１の勾配−−０，９０６、実験
例１．２の勾配−一０．９０４であり、実験条件の違い
に関係なく、きわめて近い数値を示している。V2=VIVo・−・−・(11 Figure 3 shows the relationship between the applied voltage V2 between the measurement electrodes 10 and the concentration C in a logarithmic manner, and since it is represented by a straight line, the applied voltage V2 It can be seen that there is a logarithmic relationship between and the concentration C.The slopes of the straight line graphs of Experimental Examples 1.1 and 1.2 are the slope of Experimental Example 1.1 - -0,906, and the slope of Experimental Example 1.2. -10.904, indicating extremely close values regardless of the differences in experimental conditions.
つぎに、太陽電池７０からのＥＭＦの値が、印加電圧■
２と濃度Ｃの相関関係を示すＩｎ（Ｖ。Next, the value of EMF from the solar cell 70 is determined by the applied voltage ■
In(V) showing the correlation between 2 and concentration C.
）−Ｉｎ（Ｃ）直線の勾配に及ぼす影響を検討した。第
１表は、ＥＭＦを０．２００ Ｖ〜０．４５０ Ｖの間
番こ設定して、Ｉｎ （Ｖｇ ） ！ ｎ （Ｃ）
直線の勾配を求めた結果を示している。表中、ｎは測定
点の数を示す。)-In(C) The influence on the slope of the straight line was investigated. Table 1 shows that the EMF is set between 0.200 V and 0.450 V, and In (Vg)! n (C)
This shows the results of finding the slope of the straight line. In the table, n indicates the number of measurement points.
８
９
第１表の結果によれば、Ｅ Ｍ Ｆの値に関係なく、何
れも良好な直線関係を示すとともに１．直線の勾配はほ
ぼ等しくなった。8 9 According to the results in Table 1, regardless of the value of EMF, all of them show a good linear relationship, and 1. The slopes of the lines are almost equal.
以上のことから、豆電球４ｏの種類や太陽電池７０のＥ
ＭＦ、ずなわち測定回路５ｏを流れる電流（ｎ１１↓：
１、一定でさえあれば、その高似ジオ前記Ｉｎ（Ｖ＝
） −１ｎ （Ｃ）直線の勾配に影響を及はさないこ
とか判る。したがって、予め、濃度Ｃか判っている試料
液に対して、印加電圧Ｖ２と濃度Ｃの相関関係を測定し
グラフにしてお６ノば、濃度Ｃが未知の被測定液Ｗにつ
いて印加電圧Ｖ２を測定し、前記グラフに当てはめるこ
とによって濃度Ｃの埴を知ることができる。また、広い
濃度範囲で良如′な直線関係を示していることから、広
範四の濃度／ｌｌす定に適用できることも判る。From the above, the types of miniature light bulbs 4o and the E of solar cells 70
MF, that is, the current flowing through the measurement circuit 5o (n11↓:
1. As long as it is constant, its high similarity geo In(V=
) -1n (C) It can be seen that it does not affect the slope of the straight line. Therefore, if the correlation between the applied voltage V2 and the concentration C is measured and graphed in advance for a sample liquid whose concentration C is known, then the applied voltage V2 can be calculated for a sample liquid W whose concentration C is unknown. By measuring and applying it to the graph above, the concentration C can be determined. Furthermore, since a good linear relationship is shown over a wide concentration range, it can be seen that it can be applied to a wide range of concentrations of 4/11.
なお、第１図の装置を使用して、交流電源装置３０の印
加電圧Ｖｌを一定とした場合に、太陽電池７０のＥＭＦ
と試料の濃度Ｃとの関係を測定したところ、狭い濃度範
囲でしか良好な相関関係を示さなかったことから、本願
発明のように、測定０
回路５０を流れる電流値を一定にして、印加電圧を測定
する方法のほうが、濃度測定には適していることが実証
できた。Note that when using the device shown in FIG. 1 and keeping the applied voltage Vl of the AC power supply device 30 constant, the EMF of the solar cell 70
When the relationship between C and the sample concentration C was measured, a good correlation was shown only in a narrow concentration range. It has been demonstrated that the method of measuring is more suitable for concentration measurement.
各種塩濃度の測定
４．８Ｖの豆電球４０を用い、太陽電池のｒ＝ Ｍ Ｆ
−〇、４５０Ｖ、測定温度２５°Ｃに設定して、塩化ナ
トリウム、フソ化ナトリウム、硫酸ナトリウム、および
、リン酸すトリウムの４種類の試料を用いて、異なる濃
度Ｃにおける印加電圧■２を測定し、それぞれの試料に
対する検量線のグラフを作成し、その結果を、前記した
市販の電導変針による測定結果と比較した。Measurement of various salt concentrations Using a 4.8V miniature light bulb 40, r = M F of the solar cell
- Measure the applied voltage (2) at different concentrations C using four types of samples: sodium chloride, sodium fusodide, sodium sulfate, and thorium phosphate, by setting the temperature to 450V and 25°C. A calibration curve graph was created for each sample, and the results were compared with the measurement results using the commercially available conductive needle described above.
第４図は、塩化す１〜リウムについての試験結果を示し
ている。本願発明にかかる実施例１１では、濃度Ｃの増
加番ご伴って印加電圧Ｖ２ば双曲線状に減少しており、
良好な対数関係になっているのに対し、市販電導変針に
よる比較例１．１てば、濃度Ｃと電導度にとはほぼ直線
関係を示しているが、濃度Ｃが高くなると直線からのス
レが生じており、高濃度範囲では誤差が生していること
が判る１
第５図は、上記測定結果を、対数グラフに示したもので
あり、比較例１．１（市販電導計）では右上がり直線と
なり、実施例１．１（本願発明装置）では左上がり直線
になっている。それぞれの相関係数ｒを求めると、比較
例１はｒ＝０．９９９９に対し、実施例１はｒ＝０．９
９９１であり、本願発明の測定方法でも充分に実用的な
測定精度が得られることが実証できた。FIG. 4 shows the test results for mono-lithium chloride. In Example 11 according to the present invention, the applied voltage V2 decreases hyperbolically as the concentration C increases,
While there is a good logarithmic relationship, Comparative Example 1.1 using a commercially available conductivity curve shows an almost linear relationship between the concentration C and the conductivity, but as the concentration C increases, there is a deviation from the straight line. It can be seen that there is an error in the high concentration range.1 Figure 5 shows the above measurement results in a logarithmic graph. In Example 1.1 (apparatus of the present invention), it is a straight line rising upward to the left. When calculating the respective correlation coefficients, Comparative Example 1 has r=0.9999, while Example 1 has r=0.9.
991, demonstrating that the measurement method of the present invention can also provide sufficient practical measurement accuracy.
試料をフソ化ナトリウム、硫酸す１〜リウム、リン酸す
トリウムに変えて、同様の検量線を作成した。その結果
を第２表に示しており、相関直線の勾配は、Ｎａ” イ
オンの対イオンの種類により若干異なっているが、比較
例１．１では＋１、本願発明の実施例１，１では−１で
あり、何れも極めて１に近い値となっている。このこと
から、本願発明の測定方法および測定装置によれば、測
定電極１０間の印加電圧Ｖ２と濃度Ｃが、１対ｌの良好
な相関関係を示し、印加電圧Ｖ２の測定によって正確な
濃度Ｃの値が求められることが実証できた。A similar calibration curve was created by changing the samples to sodium fusodide, sodium sulfate, sodium sulfate, and sodium phosphate. The results are shown in Table 2, and the slope of the correlation line differs slightly depending on the type of counter ion of the Na'' ion, but it is +1 in Comparative Example 1.1 and - in Examples 1 and 1 of the present invention. 1, and both values are extremely close to 1. Therefore, according to the measuring method and measuring device of the present invention, the applied voltage V2 between the measuring electrodes 10 and the concentration C are in a good ratio of 1 to 1. It was demonstrated that an accurate value of the concentration C can be determined by measuring the applied voltage V2.
２
２３
また、上記測定装置を用いて、約１ケ月間隔で１年間に
わたって、ＮａＣ１の検量線データをとったところ、そ
の勾配および切片には、０．５％以下の誤差しか認めら
れなかったことから、本願発明の測定方法および測定装
置は、再現性もしくは性能安定性の点でもきわめて優れ
ていることが実証できた。特に、測定電極１０として、
高価な白金を用いず、ステンレス製電極を用いても良好
な性能を発揮できることが実証できた。2 23 In addition, when the calibration curve data of NaCl was taken at approximately monthly intervals over a period of one year using the above measuring device, an error of less than 0.5% was observed in the slope and intercept. Therefore, it was demonstrated that the measuring method and measuring device of the present invention are extremely excellent in terms of reproducibility and performance stability. In particular, as the measurement electrode 10,
We were able to demonstrate that good performance could be achieved using stainless steel electrodes without using expensive platinum.
さらに、別の実施例として、測定電極１０として、直径
２．５ｃｍの円形ステンレス金網１４枚を用いた測定装
置で、印加電圧■１を２００Ｖにして、０．０１ ｐｐ
ｍｍ以下の微量のＮａＣ］濃度を測定することも出来た
。Furthermore, as another example, in a measuring device using 14 circular stainless wire meshes with a diameter of 2.5 cm as the measuring electrodes 10, the applied voltage (1) was set to 200 V, and 0.01 pp.
It was also possible to measure the concentration of NaC in trace amounts of less than mm.
陰イオン界面活性剤のｃｍｃの決定
この発明にかかる測定方法の適用例として、ＳＤＳ、Ｄ
ＢＳ、ラウリン酸ナトリウム、ミリスチン酸すトリウム
の４種類の陰イオン界面活性剤水溶液の、濃度変化に伴
う電導度変化を測定し、各温度での、それぞれの界面活
性剤のｃｍｃ（臨界４
ミセル濃度、ｃｒｉｔｉｃａｌ ｍ１ｃｅｌｌｅ ｃｏ
ｎｃｅｎｔｒａｔｉｏｎ）の決定を行った。Determination of cmc of anionic surfactants As an application example of the measurement method according to this invention, SDS, D
We measured the conductivity changes associated with changes in concentration of four types of anionic surfactant aqueous solutions: BS, sodium laurate, and sterium myristate, and measured the cmc (critical 4 micelle concentration) of each surfactant at each temperature. , critical m1celle co
The determination of centration was made.
前記したような測定方法で、測定電極１０間の印加電圧
Ｖ２と界面活性剤の濃度Ｃの関係を、対数でプロソトし
て得られた２直線の交点がｃ ｍ ｃ。The intersection of two straight lines obtained by calculating the relationship between the voltage V2 applied between the measurement electrodes 10 and the concentration C of the surfactant using a logarithm using the measurement method described above is cm c.
に相当することになる。It will be equivalent to .
本願発明にかかる実施例２．１と、前記同様の市販電導
針による比較例２．１について、２５°ＣにおけるＳＤ
Ｓ水／水液８液定し、その結果を第６図に示している。Regarding Example 2.1 according to the present invention and Comparative Example 2.1 using the same commercially available conductive needle, the SD at 25°C
Eight S water/aqueous solutions were determined and the results are shown in FIG.
グラフ中、Ｍ点がＣ，ｍ Ｃを示しており、実施例２．
１で測定されたＳＤＳのｃ ｍ ｃ値は７、８６ｍ ｍ
ｏｌ／Ａであり、比較例２．１てば８．０４ｍｍｏｌ／
１であった。文献等で知られているＳＤＳのｃｍｃ値
と比較すると、非常によい一致を示していた。In the graph, point M indicates C, mC, and Example 2.
The SDS c m c value measured at 1 is 7,86 m m
ol/A, Comparative Example 2.1 8.04 mmol/
It was 1. A comparison with the cmc value of SDS known from literature etc. showed very good agreement.
第３表は、ＳＤＳ以外の試料についても同様の測定を行
って、その結果をまとめたものである。Table 3 summarizes the results obtained by performing similar measurements on samples other than SDS.
５
表中、勾配Ｉは、濃度ＣがＣｍＣよりも低い領域におけ
る相関直線の勾配を示し、勾配■は、濃度Ｃがｃｍｃよ
りも低い領域における相関直線の勾配を示している。何
れの測定結果も、文献等で知られている各試料のｃｍｃ
値とよい一致を示しており、本願発明が界面活性剤のｃ
ｍ ｃ値決定に有用であることが実証できた。5 In the table, slope I indicates the slope of the correlation line in the region where the concentration C is lower than CmC, and slope ■ indicates the slope of the correlation line in the region where the concentration C is lower than cmc. All measurement results are based on the cmc of each sample known from literature, etc.
The present invention shows good agreement with the surfactant c
It has been demonstrated that this method is useful for determining m c values.
なお、勾配Ｉと勾配■は、界面活性剤の種類によって異
なる傾向が認められた。Incidentally, it was observed that the gradient I and the gradient ■ tended to differ depending on the type of surfactant.
水道水中の電解質の検出
本願発明の測定方法および装置の別の適用例として、水
道水に含まれる電解質の検出を行った。Detection of electrolytes in tap water As another application example of the measuring method and apparatus of the present invention, electrolytes contained in tap water were detected.
２５°Ｃにおいて、太陽電池のＥＭＦを、０．２００Ｖ
〜０．４．５０ Ｖの範囲で異なるＥＭＦに設定して、
印加電圧Ｖ２を測定した。前記第１表に示された塩化ナ
トリウムの検量線をもとにして、電解質濃度を塩化ナト
リウム濃度に換算してみた。その結果を第４表に示して
いる。At 25°C, the EMF of the solar cell is 0.200V.
Set to different EMF in the range ~0.4.50 V,
The applied voltage V2 was measured. Based on the sodium chloride calibration curve shown in Table 1 above, the electrolyte concentration was converted into sodium chloride concentration. The results are shown in Table 4.
７
８
上表の結果、ＥＭＦの値に関係なく、電解質濃度Ｃ（，
１約７０ｐｐｍ （１，２７〜１．３０ｍ ｍｏｌ、
ｌ）を示し、前記した市販の電導度肝を用いた比較例４
゜０の−１り定値と−・致した結果が得られた。7 8 As a result of the above table, regardless of the EMF value, the electrolyte concentration C (,
1 about 70 ppm (1,27-1.30 m mol,
Comparative Example 4 using the commercially available conductivity scale shown in l) and described above.
A result was obtained that agreed with the -1 constant value of °0.
ノニオン界面活性剤のｃｍｃ決定
この発明にかかる測定方法を応用して、ノニオン界面活
性剤のＣｍ Ｃ，値の測定を行った。基本的な測定方法
は、前記した陰イオン界面活性剤の測定と同様に実施し
た。Determination of cmc of nonionic surfactants The CmC value of nonionic surfactants was measured by applying the measurement method according to the present invention. The basic measurement method was the same as the measurement of the anionic surfactant described above.
試料として、ＡＰＥ＝Ｃ，□Ｈ，５（Ｅ○）６を用い、
２５°Ｃにおける印加電圧Ｖ２と濃度Ｃの関係をグラフ
に表した結果を、第７図に示している。なお、被測定／
夜には、塩化ナトリウム７Ｑｐｐｍを共存さ−ＩＪ−た
状態でＩ１１定を行った。Using APE=C, □H, 5(E○)6 as a sample,
The graph of the relationship between the applied voltage V2 and the concentration C at 25° C. is shown in FIG. In addition, the measured/
In the evening, I11 determination was carried out in the presence of 7Qppm of sodium chloride.
その結果、ｃ ｍ ｃ値は９９．４４μｍｏｌ／ Ｅで
あった。また、同様の試験を別のノニオン界面活性剤で
行った結果をまとめて、第５表に示す。As a result, the cmc value was 99.44 μmol/E. Further, the results of similar tests conducted with other nonionic surfactants are summarized in Table 5.
９
第５表
上記結果から、本願発明がノニオン界面活性剤のｃ ｍ
ｃ測定にも利用できることが実証できた。9 From the above results in Table 5, it can be seen that the present invention has a nonionic surfactant c m
It was demonstrated that this method can also be used for c measurement.
なお、ノニオン界面活性剤には、電導度に関係する基は
含まれていないため、そのまま単独で濃度を変えて電導
度を測定したとしても、前記第（１図に示された陰イオ
ン界面活性剤のような、電導度と濃度の相関直線の変曲
点は表れず、ｃｍｃ値を法定することは出来ない。In addition, since nonionic surfactants do not contain groups related to conductivity, even if the conductivity is measured by changing the concentration of nonionic surfactants, the anionic surfactants shown in Figure 1 (see Figure 1) cannot be measured. There is no inflection point on the correlation line between conductivity and concentration, as in the case of agents, and the cmc value cannot be determined legally.
しかし、前記したように、ノニオン界面活性剤とともに
、少量の電解質、例えば、ＮａＣｌやｔｂｉｚｓＯａ等
を、約５〜１１００ｐｐ程度添加した系で測定を行うと
、系中の水分子の界面活性剤親水基への水和が起こり、
相対的にバルク水中の電解質濃度が増加する。この電解
質濃度は、界面活性剤量が増加するにしたがって増加す
るので、その結果、系企体の抵抗が減り電導度が高まる
ことになる。特に、臨界尖セル濃度前後では、上記電導
度の変化か大きくなるので、電導度と濃度の相関直線に
凹面な変曲点が表れるのである。この臨界ミセル濃度に
おける電導度の変化ば、疎水基による構造水の増加によ
るものと考えられる。However, as mentioned above, when measurements are carried out in a system in which a small amount of electrolyte such as NaCl or tbizsOa is added together with a nonionic surfactant at an amount of about 5 to 1100 pp, it is found that the hydrophilic groups of the surfactant in the water molecules in the system are hydration occurs,
Relatively, the electrolyte concentration in bulk water increases. This electrolyte concentration increases as the amount of surfactant increases, resulting in decreased resistance and increased conductivity of the system. In particular, the change in conductivity becomes large before and after the critical cusp cell concentration, so that a concave inflection point appears on the correlation line between conductivity and concentration. The change in electrical conductivity at this critical micelle concentration is considered to be due to an increase in structural water due to hydrophobic groups.
なお、上記方法は、ｃ ｒｎ ｃ値の決定だけでなく、
ノニオン界面活性剤の濃度測定にも利用できることは言
うまでもない。Note that the above method not only determines the cr c value, but also
Needless to say, it can also be used to measure the concentration of nonionic surfactants.
電導度滴定装置
この発明を電導度滴定に利用するための装置を製造した
。Conductivity Titration Apparatus An apparatus for applying the present invention to conductivity titration was manufactured.
第８図および第９図に滴定装置の構造を示しており、基
本的には前記第１図に示した測定装置と同様であるので
、共通する構造部分には同し符号を付け、重複する説明
は省略する。Figures 8 and 9 show the structure of the titration device, and since it is basically the same as the measuring device shown in Figure 1 above, common structural parts are given the same reference numerals and duplicates are shown. Explanation will be omitted.
滴定に用いる一方の反応ｌ夜Ｗを入れておく測定容器２
０はコニカルビーカーを使用し、前記同様の恒温槽２１
に収容されている。他方の反応液は１
、上記測定容器にピペソト笠を用いて所定量づつ滴下す
る。電極１０を装着した測定ユニソト９０が測定容器２
０内に投入されている。測定ユニノド９０には測定回路
５０が取りイ」けられ、電極１０と直列に電源装置３０
および豆電球４０が接続されている。豆電球４０はビニ
ルバイブロ０の端に装着され、他端には太陽電池７０が
装着されている。太陽電池７０には電圧検出用のテスタ
ー８０が接続されている。Measuring container 2 containing one of the reactions used for titration.
0 uses a conical beaker and the same temperature chamber 21 as above.
is housed in. A predetermined amount of the other reaction solution is added dropwise into the measurement container using a pipette cap. The measurement unit 90 equipped with the electrode 10 is the measurement container 2.
It is inserted into 0. A measurement circuit 50 is installed in the measurement unit node 90, and a power supply device 30 is connected in series with the electrode 10.
and a miniature light bulb 40 are connected. A miniature light bulb 40 is attached to one end of the vinyl vibro 0, and a solar cell 70 is attached to the other end. A voltage detection tester 80 is connected to the solar cell 70.
測定ユニット９０の詳細構造を第９図に示しており、塩
化ビニルパイプからなる筒体９１の一端近くて両側に対
称的に切り欠き９２．９２を設り、切り欠き９２．９２
内に、互いに対向させて一対のステンレス金網からなる
電極１０．１０を取りイ」りでいる。電極１０．１０に
は配線９３か接続され、筒体９１の他端で配線９３は測
定回路５０と連結される。筒体９１内の配線９３ば、ビ
ニルホース９４に挿通して保護されている。The detailed structure of the measurement unit 90 is shown in FIG. 9, in which notches 92.92 are provided symmetrically on both sides near one end of a cylindrical body 91 made of a vinyl chloride pipe.
Inside, a pair of electrodes 10 and 10 made of stainless steel wire mesh are placed facing each other. A wiring 93 is connected to the electrode 10.10, and the wiring 93 is connected to the measuring circuit 50 at the other end of the cylinder 91. The wiring 93 inside the cylindrical body 91 is protected by being inserted into a vinyl hose 94.
上記のような構造の滴定装置を使用するには、測定容器
２０に一方の反応液を一定量入れておき２
、他方の反応液をホールピペソト等を用いて所定量つづ
滴下していき、そのときの測定容器２ｏ内の溶液Ｗの電
導度を測定する。電導度の測定は、太陽電池７０のＥＭ
Ｆが一定の値、例えば０．２００Ｖになるように電源装
置３０の印加電圧■、を調整して、その印加電圧値と測
定溶液Ｗの電導度の変化量との関係を測定する。測定溶
液Ｗのイオン濃度が無限大の場合の印加電圧すなわち基
準電圧■２は、豆電球４０を直接電源装置３０に接続し
た状態で、太陽電池７０のＥＭＦが前記一定値になると
きの印加電圧を測定しておく。To use the titration device with the above structure, put a certain amount of one reaction liquid into the measuring container 20, drop the other reaction liquid in a predetermined amount using a pipette, etc. The conductivity of the solution W in the measurement container 2o is measured. The electrical conductivity is measured using the EM of the solar cell 70.
The applied voltage (2) of the power supply device 30 is adjusted so that F is a constant value, for example, 0.200 V, and the relationship between the applied voltage value and the amount of change in the conductivity of the measurement solution W is measured. The applied voltage when the ion concentration of the measurement solution W is infinite, that is, the reference voltage (2), is the applied voltage when the EMF of the solar cell 70 reaches the constant value with the miniature light bulb 40 directly connected to the power supply device 30. Measure.
中和滴定への利用
上記構造の滴定装置を用いて中和滴定を行った。具体的
には、０．１Ｎ塩酸２００ｍ１を１Ｎ水酸化ナトリウム
で中和した。ＩＮ水酸化ナトリウムの滴下量を徐々に増
やしながら、太陽電池７０のＥＭＦを一定値にするのに
必要な印加電圧Ｖ２の値を測定した。印加電圧ｖ２が、
Ｖ２＝Ｖ、−Ｖ。Use in neutralization titration Neutralization titration was performed using the titration device with the above structure. Specifically, 200 ml of 0.1N hydrochloric acid was neutralized with 1N sodium hydroxide. While gradually increasing the amount of IN sodium hydroxide dropped, the value of the applied voltage V2 required to maintain the EMF of the solar cell 70 at a constant value was measured. The applied voltage v2 is
V2=V, -V.
で算出されるのは前記同様である。is calculated in the same way as above.
第１０図に測定結果を示している。なお、印加３
電圧■、はＩｎ（Ｖ）すなわち対数で表している。グラ
フの凸状の変曲点が中和点であり、ＩＮ水酸化すトリウ
ムの滴下量が２０．２ｍｌで中和したことを示している
。理論上は、ＩＮ水酸化すトリウムの滴下量が２０．０
ｍｌで中和するので、前記実測値りよ理論値に極めて近
く、この発明にかかる電導度の測定方法を中和滴定に利
用できることが実計できた。なお、上記理論値と実測値
の差は、試薬調製誤差や大気中のＣＯ２の影響専である
と名えられる。Figure 10 shows the measurement results. Note that the applied voltage 3 is expressed in In(V), that is, logarithmically. The convex inflection point of the graph is the neutralization point, which indicates that the amount of dropped IN thorium hydroxide was 20.2 ml for neutralization. Theoretically, the amount of IN thorium hydroxide dropped is 20.0
ml, the actual value was much closer to the theoretical value than the actual value, and it was confirmed that the method for measuring electrical conductivity according to the present invention can be used for neutralization titration. It should be noted that the difference between the theoretical value and the measured value can be said to be caused solely by reagent preparation errors and the influence of CO2 in the atmosphere.
中和点での反応生成物であるＮａＣｌ量を、予め作成し
ておいたＮａ Ｃ１１度の検量線から求めたところ、２
１．３ｍ ｍｏｌ となり、理論値である２０．０ｍｍ
ｏｌ とほぼ一致することも確認できた。The amount of NaCl, which is a reaction product at the neutralization point, was determined from a previously prepared calibration curve of 11 degrees NaCl.
1.3m mol, which is the theoretical value of 20.0mm
It was also confirmed that it almost coincides with ol.
別の実施例として、ｌＮ１１［と］Ｎ水酸化ナトリウム
による弱酸と強塩基の中和反応についても、上記同様の
中和滴定を行ったところ、やはり良好な結果が得られた
。As another example, neutralization titration similar to the above was performed for the neutralization reaction of a weak acid and a strong base using 1N11[]N sodium hydroxide, and good results were also obtained.
沈澱滴定への利用
前記構造の滴定装置を沈Ｆｍ、滴定に用いた。具体４
的には、５．ＯＸｌｏ−２Ｍ塩化ハ’） ラム１００ｍ
ｌニ対し５．０Ｘ１０−２Ｍ硫酸ナトリウムで沈澱滴定
を行った。Use in precipitation titration The titration apparatus having the above structure was used for precipitation titration. Specifically, 5. OXlo-2M Chloride Ha') Ram 100m
Precipitation titration was performed using 5.0 x 10-2M sodium sulfate against 1.
その結果を第１１図に示しており、硫酸ナトリウムの滴
下量がｌｏｏｍｌのときに、印加電圧Ｖ２が最大、すな
わち測定溶液の電導度が最小になることが判り、この実
測値は理論値と一致しているしたがって、この発明にか
かる電導度の測定方法を沈澱滴定に利用できることが実
証された。The results are shown in Figure 11, and it can be seen that when the amount of sodium sulfate dropped is looml, the applied voltage V2 is the maximum, that is, the conductivity of the measured solution is the minimum, and this measured value is the same as the theoretical value. Therefore, it was demonstrated that the method for measuring electrical conductivity according to the present invention can be used for precipitation titration.
以上に述べた、この発明のうち、請求項１記載の電導度
の測定方法は、測定電極間を流れる電流値が所定の電流
値になるような印加電圧の値を測定して、被測定液の電
導度を測定するものであり、従来のように、ホイートス
トンブリッジを利用して、測定電極間の抵抗値を直接測
定する方法に比べ、ホイートストンブリッジ等の複雑な
回路構造が不要になり、また、ホイートストンブリッジ
回路の面倒な調整作業も必要ないため、極めて簡５
単に電導度を測定できるようになる。The method for measuring electrical conductivity according to claim 1 of the present invention described above measures the value of the applied voltage such that the current value flowing between the measurement electrodes becomes a predetermined current value, and Compared to the conventional method that uses a Wheatstone bridge to directly measure the resistance value between measurement electrodes, it eliminates the need for a complicated circuit structure such as a Wheatstone bridge. Since there is no need for troublesome adjustment of the Wheatstone bridge circuit, conductivity can be measured extremely easily.
請求項２記載の電導度の測定装置は、上記訂１求項１記
載の測定方法を実施する装置であって、／！［す定電極
、電圧印加手段、電流検出手段、印加電圧変更手段、お
よび、印加電圧検出手段は何れも、−船釣な計測機型環
で用いられている、電源や電圧計、電流計等をそのまま
利用することができ、極めて簡単な構造で、しかも正確
に電導度を測定することが可能になる。測定電極として
、高価な白金を使用せず、比較的安価なステンレスを用
いても、良好な性能が発揮できるので、電極の構造を自
由に設定できるとともに、経済性にも優れたものとなる
。The electrical conductivity measuring device according to claim 2 is an apparatus for carrying out the measuring method according to claim 1, wherein /! [The constant electrode, the voltage applying means, the current detecting means, the applied voltage changing means, and the applied voltage detecting means are all equipped with power supplies, voltmeters, ammeters, etc., which are used in measuring instrument type rings for boat fishing. can be used as is, making it possible to accurately measure conductivity with an extremely simple structure. Good performance can be achieved even when relatively inexpensive stainless steel is used as the measurement electrode instead of using expensive platinum, so the structure of the electrode can be freely set and is also excellent in economy.
特に、各構成手段の機能や構造が判り易いので、教育用
の実験装置として利用した場合には、測定原理の説明が
理解し易く、教育効果が上がる。In particular, since the function and structure of each constituent means are easy to understand, when used as an experimental device for educational purposes, the explanation of the measurement principle is easy to understand and the educational effect is increased.
複雑な操作や調整が不要であるので、測定装置を各種製
品に組み込んで、簡単に電導度の測定を行うことができ
る。具体的には、例えば、家庭用洗濯機の水槽に組み込
んで、すすぎ水の水質の変化６
、すなわち洗剤成分が無くなったことを検出すること等
が可能になる。Since no complicated operations or adjustments are required, the measuring device can be incorporated into various products to easily measure conductivity. Specifically, for example, it can be installed in a water tank of a household washing machine to detect a change in the water quality of the rinse water, that is, the disappearance of detergent components.
請求項３記載の濃度の測定方法は、上記請求項１記載の
測定方法および請求項２記載の測定装置を使用する方法
であり、印加電圧と濃度の相関関係が極めて良好である
ため、正確な濃度を非常に簡単な測定装置で、しかも簡
単な操作で測定できることになる。The concentration measuring method according to claim 3 is a method using the measuring method according to claim 1 and the measuring device according to claim 2, and since the correlation between the applied voltage and the concentration is extremely good, it is possible to accurately measure the concentration. The concentration can be measured with a very simple measuring device and with simple operations.
第４図はこの発明の実施例にかかる測定装置の概略１１
４造図、第２図は印加電圧と濃度の関係を示すグラフ図
、第３図はＥＭＦの違いよる測定結果を示すグラフ図、
第４図はこの発明の実施例と比較例について印加電圧と
濃度の関係を京ずグラフ図、第５図は検量線を示すグラ
フ図、第６図は臨界ミセル濃度の測定結果を示すグラフ
図、第７図はノニオン界面活性剤に対する臨界ミセル濃
度の測定結果を示すグラフ図、第８図はこの発明の実施
例にかかる滴定装置の全体構造図、第９図は測定ユニノ
ドの拡大斜視図、第１０図は中和滴定試７
験の結果を示すグラフ図、第１１図は沈＃滴定試験の結
果を示すグラフ図、第１２図は従来例の回路構成を示す
概略図である。
１０．１０・・・測定電極 ２０・・・測定容器 ３０
・・・交流電源装置 ３２・・・電圧計 ４０・・・豆
電球５０・・・測定回路 ７０・・・太陽電池 ８０・
・・電圧計Ｗ・・・被測定液FIG. 4 is a schematic diagram 11 of a measuring device according to an embodiment of the present invention.
4 diagrams, Figure 2 is a graph showing the relationship between applied voltage and concentration, Figure 3 is a graph showing measurement results based on differences in EMF,
Fig. 4 is a graph showing the relationship between applied voltage and concentration for Examples and Comparative Examples of the present invention, Fig. 5 is a graph showing the calibration curve, and Fig. 6 is a graph showing the measurement results of critical micelle concentration. , FIG. 7 is a graph showing the measurement results of critical micelle concentration for nonionic surfactants, FIG. 8 is an overall structural diagram of a titration apparatus according to an embodiment of the present invention, and FIG. 9 is an enlarged perspective view of a measurement unit. FIG. 10 is a graph showing the results of the neutralization titration test 7, FIG. 11 is a graph showing the results of the precipitation titration test, and FIG. 12 is a schematic diagram showing the circuit configuration of a conventional example. 10.10...Measuring electrode 20...Measuring container 30
...AC power supply device 32...Voltmeter 40...Miniature light bulb 50...Measuring circuit 70...Solar cell 80.
...Voltmeter W...Measurement liquid
Claims (1)
加し、測定電極間を流れる電流値が所定の電流値になる
ように印加電圧を変化させ、このときの印加電圧値に基
づいて被測定液の電導度を算出する電導度の測定方法。 ２ 被測定液に投入される一対の測定電極と、測定電極
間に電圧を印加する電圧印加手段と、測定電極間に流れ
る電流値を検出する電流検出手段と、電流検出手段で検
出される電流値が所定の値になるように印加電圧を変化
させる印加電圧変更手段と、印加電圧値を検出する印加
電圧検出手段とからなる電導度の測定装置。 ３ 被測定液に投入された一対の測定電極間に電圧を印
加したとき、測定電極間を流れる電流値が一定の場合に
、印加電圧と被測定液中の特定成分の濃度との間におけ
る相関関係をもとにして、所定の電流値になるように印
加電圧を変化させたときの印加電圧の値から被測定液の
特定成分の濃度を算出する濃度の測定方法。[Claims] 1. A voltage is applied between a pair of measurement electrodes placed in a liquid to be measured, and the applied voltage is changed so that the current value flowing between the measurement electrodes becomes a predetermined current value. A conductivity measurement method that calculates the conductivity of a liquid to be measured based on the applied voltage value. 2. A pair of measuring electrodes that are introduced into the liquid to be measured, a voltage applying means that applies a voltage between the measuring electrodes, a current detecting means that detects the value of the current flowing between the measuring electrodes, and a current detected by the current detecting means. A conductivity measuring device comprising applied voltage changing means for changing the applied voltage so that the value becomes a predetermined value, and applied voltage detecting means for detecting the applied voltage value. 3. Correlation between the applied voltage and the concentration of a specific component in the liquid to be measured when a voltage is applied between a pair of measurement electrodes inserted into the liquid to be measured and the current value flowing between the measurement electrodes is constant. A concentration measurement method in which the concentration of a specific component in a liquid to be measured is calculated from the value of the applied voltage when the applied voltage is changed to a predetermined current value based on the relationship.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1171566A JP2523183B2 (en) | 1989-07-03 | 1989-07-03 | Method for measuring critical micelle concentration of nonionic surfactants |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1171566A JP2523183B2 (en) | 1989-07-03 | 1989-07-03 | Method for measuring critical micelle concentration of nonionic surfactants |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0337558A true JPH0337558A (en) | 1991-02-18 |
| JP2523183B2 JP2523183B2 (en) | 1996-08-07 |
Family
ID=15925519
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1171566A Expired - Fee Related JP2523183B2 (en) | 1989-07-03 | 1989-07-03 | Method for measuring critical micelle concentration of nonionic surfactants |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2523183B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0572161A (en) * | 1991-03-01 | 1993-03-23 | Archer Daniels Midland Co | Stability measuring apparatus for autoxidation compound and fat and oil |
| CN105588857A (en) * | 2015-12-15 | 2016-05-18 | 北京农业质量标准与检测技术研究中心 | Surface active agent detection device |
| CN114689661A (en) * | 2022-03-14 | 2022-07-01 | 贵州胜威化工新材料研究院有限公司 | Conductivity titration method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102248106B1 (en) * | 2019-11-06 | 2021-05-04 | 서강대학교산학협력단 | Method of measuring the critical micelle concentration of a surfactant using mass spectrometry |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS495399A (en) * | 1972-04-28 | 1974-01-18 | ||
| JPS5267699A (en) * | 1975-12-03 | 1977-06-04 | Fujihira Kougiyou Kk | Measuring method and apparatus for organic acid contents |
| JPS60155952A (en) * | 1984-01-25 | 1985-08-16 | Denki Kagaku Keiki Co Ltd | Measurement of concentration |
-
1989
- 1989-07-03 JP JP1171566A patent/JP2523183B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS495399A (en) * | 1972-04-28 | 1974-01-18 | ||
| JPS5267699A (en) * | 1975-12-03 | 1977-06-04 | Fujihira Kougiyou Kk | Measuring method and apparatus for organic acid contents |
| JPS60155952A (en) * | 1984-01-25 | 1985-08-16 | Denki Kagaku Keiki Co Ltd | Measurement of concentration |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0572161A (en) * | 1991-03-01 | 1993-03-23 | Archer Daniels Midland Co | Stability measuring apparatus for autoxidation compound and fat and oil |
| CN105588857A (en) * | 2015-12-15 | 2016-05-18 | 北京农业质量标准与检测技术研究中心 | Surface active agent detection device |
| CN114689661A (en) * | 2022-03-14 | 2022-07-01 | 贵州胜威化工新材料研究院有限公司 | Conductivity titration method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2523183B2 (en) | 1996-08-07 |
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