JP2020060371A - Reagent-less residual chlorine measuring device and reagent-less residual chlorine measuring method - Google Patents

Reagent-less residual chlorine measuring device and reagent-less residual chlorine measuring method Download PDF

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JP2020060371A
JP2020060371A JP2018189519A JP2018189519A JP2020060371A JP 2020060371 A JP2020060371 A JP 2020060371A JP 2018189519 A JP2018189519 A JP 2018189519A JP 2018189519 A JP2018189519 A JP 2018189519A JP 2020060371 A JP2020060371 A JP 2020060371A
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residual chlorine
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美由貴 浦田
Miyuki Urata
美由貴 浦田
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DKK TOA Corp
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Abstract

To provide a reagent-less residual chlorine measuring device for measuring both the free residual chlorine concentration and the combined residual chlorine concentration with accuracy that can be practically used, without using a reagent containing halogen ions.SOLUTION: A reagent-less residual chlorine measuring device that applies sequentially a first applied voltage V, which is selected from the range of -730 to -770 mV, a second applied voltage Vselected from -780 to -820 mV range, and a third applied voltage Vselected from -830 to -870 mV range between a gold detection electrode 13 and a platinum counter electrode 15, measures a first redox current I (V) when the first applied voltage Vis applied, a second redox current I (V) when the second applied voltage Vis applied, and a third redox current I (V) when the third applied voltage Vis applied, and calculates the free residual chlorine concentration Nf based on the following formula (1). Nf=A×I(V)+B×I(V)+C×I(V)+D...(1)SELECTED DRAWING: Figure 1

Description

本発明は無試薬式残留塩素測定装置及び無試薬式残留塩素測定方法に関する。さらに詳しくは、電極を交換することなく、結合残留塩素による妨害を排して遊離残留塩素濃度を測定でき、さらには、電極を交換することなく、遊離残留塩素濃度に加えて、全残留塩素濃度と結合残留塩素濃度も測定可能な無試薬式残留塩素測定装置及び無試薬式残留塩素測定方法に関する。   The present invention relates to a reagentless residual chlorine measuring apparatus and a reagentless residual chlorine measuring method. More specifically, it is possible to measure the free residual chlorine concentration without exchanging bound residual chlorine without replacing the electrode. Furthermore, in addition to the free residual chlorine concentration, the total residual chlorine concentration can be measured without replacing the electrode. The present invention relates to a reagentless residual chlorine measuring device and a reagentless residual chlorine measuring method capable of measuring residual chlorine concentration combined with.

残留塩素とは、塩素処理の結果水中に残留した消毒作用のある有効塩素のことで、次亜塩素酸などの遊離残留塩素と、クロラミンのような結合残留塩素に区分される。いずれも酸化による殺菌力を有している。   Residual chlorine is effective chlorine that remains in water as a result of chlorine treatment and has a disinfecting action, and is classified into free residual chlorine such as hypochlorous acid and bound residual chlorine such as chloramine. Both have sterilizing power by oxidation.

この内、遊離残留塩素は主として塩素剤が水と反応して生成する次亜塩素酸（ＨＣｌＯ）と、これが解離した次亜塩素酸イオン（ＣｌＯ−）と、分子状塩素（Ｃｌ２）の３種類の形態をとる。上水等の通常のｐＨにおいては、ほとんどの遊離残留塩素が次亜塩素酸又は次亜塩素酸イオンとして存在する。
一方、結合残留塩素は、水中のアンモニア、アミン類、アミノ酸類と遊離残留塩素が反応して生成するもので、モノクロラミン（ＮＨ２Ｃｌ）、ジクロラミン（ＮＨＣｌ２）、トリクロラミン（ＮＣｌ３）の三種類の形態をとる。上水等の通常のｐＨにおいては、ほとんどの結合残留塩素が、モノクロラミン又はジクロラミンとして存在する。モノクロラミンとジクロラミンは、遊離残留塩素に比較すると圧倒的に弱いものの殺菌力を有している。 Of these, free residual chlorine is mainly composed of hypochlorous acid (HClO) produced by the reaction of a chlorine agent with water, hypochlorite ion (ClO − ) dissociated from this, and molecular chlorine (Cl 2 ). Take different forms. At normal pH, such as tap water, most free residual chlorine is present as hypochlorous acid or hypochlorite ions.
On the other hand, bound residual chlorine is produced by the reaction of free residual chlorine with ammonia, amines and amino acids in water. Monochloramine (NH 2 Cl), dichloramine (NHCl 2 ) and trichloramine (NCl 3 ) Takes three forms. At normal pH, such as tap water, most bound residual chlorine is present as monochloramine or dichloramine. Monochloramine and dichloramine have overwhelmingly weaker bactericidal activity than free residual chlorine.

我が国の水道法施行規則では、充分な殺菌力を確保する観点で、給水栓における水が、遊離残留塩素であれば０．１ｍｇ／Ｌ以上、結合残留塩素であれば０．４ｍｇ／Ｌ以上の残留塩素を保持すべきことを定めている。このように、殺菌力の違いを考慮して、保持すべき残留塩素の濃度も遊離残留塩素の場合と結合残留塩素の場合とで異なる。したがって、浄水場等においては、全残留塩素濃度だけでなく、遊離残留塩素濃度と結合残留塩素濃度とを区別して把握することが必要である。
また、不連続点処理による効率的な遊離残留塩素濃度の管理において、結合残留塩素と遊離残留塩素を区別して把握することが必要である。 According to the Water Supply Law Enforcement Regulations of Japan, from the viewpoint of ensuring sufficient sterilizing power, if the water in the faucet is free residual chlorine, 0.1 mg / L or more, and if it is combined residual chlorine, 0.4 mg / L or more. It specifies that residual chlorine should be retained. In this way, in consideration of the difference in sterilizing power, the concentration of residual chlorine to be retained also differs between free residual chlorine and combined residual chlorine. Therefore, in water purification plants and the like, it is necessary to distinguish not only the total residual chlorine concentration but also the free residual chlorine concentration and the combined residual chlorine concentration.
In addition, it is necessary to distinguish between bound residual chlorine and free residual chlorine in order to efficiently control the free residual chlorine concentration by discontinuity treatment.

遊離残留塩素と結合残留塩素とを区別して測定することは、種々の方法で行われている。たとえば、ｏ−トリジン比色法（ＯＴ法）では試薬添加から測定するまでの時間を変えることにより、ジエチル−ｐ−フェニレンジアミン比色法（ＤＰＤ法）では、添加する試薬を代えることにより、全残留塩素濃度（遊離残留塩素濃度と結合残留塩素濃度の合計）と遊離残留塩素濃度を各々測定できる。   Differentiating and measuring free residual chlorine and combined residual chlorine is performed by various methods. For example, in the o-tolidine colorimetric method (OT method), the time from the addition of the reagent to the measurement is changed, and in the diethyl-p-phenylenediamine colorimetric method (DPD method), by changing the added reagent, The residual chlorine concentration (sum of free residual chlorine concentration and combined residual chlorine concentration) and free residual chlorine concentration can be measured respectively.

一方、連続測定や自動化に適した方法として、検知極と対極との間に電圧を印加した際に、両電極間に流れる酸化還元電流を測定するポーラログラフ法が知られている。
しかし、ポーラログラフ法では、遊離残留塩素と結合残留塩素の双方が還元されてしまうため、両者を区別して測定することが困難である。 On the other hand, as a method suitable for continuous measurement and automation, a polarographic method is known in which a redox current flowing between both electrodes is measured when a voltage is applied between a detection electrode and a counter electrode.
However, in the polarographic method, since both free residual chlorine and combined residual chlorine are reduced, it is difficult to measure them separately.

特許文献１では、ポーラログラフ法の塩素濃度測定装置において得られる電流は、遊離残留塩素濃度に基づく電流と結合残留塩素に基づく電流の和であると見做し、二種以上の異なる電圧を印加した際の電流に基づく連立方程式を解くことにより、遊離残留塩素濃度と結合残留塩素濃度を区別して求める考え方が示されている。
そして、検知極として金電極、対極として銀／塩化銀電極を用い、二種以上の異なる電圧として１００ｍＶと−１００ｍＶを印加した際の電流を測定すると、それぞれの電流に含まれる結合残留塩素の影響分を相殺して遊離残留塩素濃度を求めることができるとされている。 In Patent Document 1, the current obtained by the polarographic chlorine concentration measuring device is considered to be the sum of the current based on the free residual chlorine concentration and the current based on the combined residual chlorine, and two or more different voltages were applied. It is shown that the free residual chlorine concentration and the combined residual chlorine concentration are separately obtained by solving the simultaneous equations based on the current.
Then, when a gold electrode was used as the detection electrode and a silver / silver chloride electrode was used as the counter electrode, and the currents when 100 mV and −100 mV were applied as two or more different voltages were measured, the effect of the combined residual chlorine contained in each current It is said that the residual residual chlorine concentration can be obtained by offsetting the amount.

しかし、特許文献１には、結合残留塩素の影響を排して遊離残留塩素濃度を求める条件が開示されているに過ぎず、遊離残留塩素濃度と結合残留塩素濃度の双方を、実用に耐える精度で測定可能な具体的な条件、すなわち、検知極と対極の種類、及び二種以上の異なる電圧の値等は示されていない。   However, Patent Document 1 only discloses the condition for eliminating the influence of combined residual chlorine to obtain the free residual chlorine concentration, and the accuracy for practical use of both the free residual chlorine concentration and the combined residual chlorine concentration is disclosed. The specific conditions that can be measured in, that is, the types of the detection electrode and the counter electrode, and the values of two or more different voltages are not shown.

また、特許文献２には、遊離残留塩素濃度と結合残留塩素濃度の双方を、実用に耐える精度で測定可能な具体的な条件として、金製の検知極と銀／塩化銀製の対極を用い、＋１００〜−５０ｍＶの範囲から選択される第１の印加電圧と、−１５０〜−２５０ｍＶの範囲から選択される第２の印加電圧を用いることが開示されている。
しかし、この条件は、ハロゲン系酸化剤にスルファミン酸又はその塩が添加された水を試料液とする特殊な場合にのみ適用できる条件であった。 Further, in Patent Document 2, a gold detection electrode and a silver / silver chloride counter electrode are used as specific conditions that can measure both the free residual chlorine concentration and the combined residual chlorine concentration with an accuracy that can withstand practical use. It is disclosed to use a first applied voltage selected from the range of +100 to -50 mV and a second applied voltage selected from the range of -150 to -250 mV.
However, this condition was applicable only in a special case where water containing sulfamic acid or its salt added to a halogen-based oxidant was used as a sample solution.

また、特許文献３には、遊離残留塩素濃度と結合残留塩素濃度の双方を、実用に耐える精度で測定可能な具体的な条件として、金製の検知極と白金製の対極を用い、−０．２〜−０．４Ｖの範囲から選択される第１の印加電圧と、−０．４〜−０．６Ｖの範囲から選択される第２の印加電圧と、−０．７〜−１．０Ｖの範囲から選択される第３の印加電圧を用いることが開示されている。
しかし、特許文献３で開示されている測定装置は、試料液にハロゲンイオンを含む試薬を添加することが必要な有試薬式の測定装置であり、ランニングコストやメンテナンスの手間がかかる点で不利であった。 Further, in Patent Document 3, a gold detection electrode and a platinum counter electrode are used as specific conditions under which both the free residual chlorine concentration and the combined residual chlorine concentration can be measured with an accuracy that can be practically used. First applied voltage selected from the range of 2 to -0.4V, second applied voltage selected from the range of -0.4 to -0.6V, and -0.7 to -1. It is disclosed to use a third applied voltage selected from the range of 0V.
However, the measuring device disclosed in Patent Document 3 is a reagent-type measuring device that requires addition of a reagent containing a halogen ion to a sample solution, and is disadvantageous in that running costs and maintenance work are required. there were.

特開平１１−１４８９１５号公報JP, 11-148915, A 特開２０１５−３４７４１号公報JP, 2015-34741, A 特開２００１−３４９８６６号公報JP 2001-349866 A

本発明は、上記事情に鑑み、ハロゲンイオンを含む試薬を用いることなく、かつ、電極を交換することなく、結合残留塩素の妨害を排して遊離残留塩素濃度を、実用に耐える精度で測定可能な新たな無試薬式残留塩素測定装置及び無試薬式残留塩素測定方法を提供すること、さらには、ハロゲンイオンを含む試薬を用いることなく、かつ、電極を交換することなく、遊離残留塩素濃度に加えて、全残留塩素濃度と結合残留塩素濃度も実用に耐える精度で測定可能な無試薬式残留塩素測定装置及び無試薬式残留塩素測定方法を提供することを課題とする。   In view of the above circumstances, the present invention can measure the free residual chlorine concentration by eliminating the interference of bound residual chlorine without using a reagent containing a halogen ion and without exchanging the electrode, with an accuracy that can be practically used. To provide a new reagentless residual chlorine measuring device and a reagentless residual chlorine measuring method, and further to obtain a free residual chlorine concentration without using a reagent containing a halogen ion and replacing an electrode. In addition, it is another object of the present invention to provide a reagentless residual chlorine measuring apparatus and a reagentless residual chlorine measuring method capable of measuring the total residual chlorine concentration and the combined residual chlorine concentration with accuracy that can be practically used.

上記の課題を達成するために鋭意検討した結果、金−白金電極を用いたポーラログラフ法で測定した場合、遊離残留塩素と結合残留塩素はポーラログラムの形状が異なることから、本発明は以下の構成を採用した。
［１］試料液に対してハロゲンイオンを含む試薬を添加しない無試薬式残留塩素測定装置であって、
試料液に浸漬される金製の検知極、及び白金製の対極と、
前記検知極と対極との間に、第１の印加電圧Ｖ１、第２の印加電圧Ｖ２、及び第３の印加電圧Ｖ３を順次与える加電圧機構と、
前記検知極と対極との間に流れる酸化還元電流を測定する電流計と、
演算制御部とを具備し、
第１の印加電圧Ｖ１は、−７３０〜−７７０ｍＶの範囲から、第２の印加電圧Ｖ２は−７８０〜−８２０ｍＶの範囲から、第３の印加電圧Ｖ３は−８３０〜−８７０ｍＶの範囲から、各々選択され、
前記電流計は、前記加電圧機構が第１の印加電圧Ｖ１を与えた際に前記検知極と対極との間に流れる第１の酸化還元電流Ｉ（Ｖ１）と、前記加電圧機構が第２の印加電圧Ｖ２を与えた際に前記検知極と対極との間に流れる第２の酸化還元電流Ｉ（Ｖ２）と、前記加電圧機構が第３の印加電圧Ｖ３を与えた際に前記検知極と対極との間に流れる第３の酸化還元電流Ｉ（Ｖ３）とを、各々測定し、
前記演算制御部は、下記式（１）に基づき、前記試料液の遊離残留塩素濃度Ｎｆを求めることを特徴とする無試薬式残留塩素測定装置。
Ｎｆ＝Ａ×Ｉ（Ｖ１）＋Ｂ×Ｉ（Ｖ２）＋Ｃ×Ｉ（Ｖ３）＋Ｄ ・・・（１）
（ただし、式（１）において、Ａ、Ｂ、Ｃ、Ｄは定数である。）
［２］前記演算制御部は、さらに、下記式（２）に基づき、前記試料液の全残留塩素濃度Ｎｔを求める［１］に記載の無試薬式残留塩素測定装置。
Ｎｔ＝Ｅ×Ｉ（Ｖ３）＋Ｆ・・・（２）
（ただし、式（２）において、Ｅ、Ｆは定数である。）
［３］前記演算制御部は、さらに、下記式（３）に基づき、前記試料液の結合残留塩素濃度Ｎｃを求める［２］に記載の無試薬式残留塩素測定装置。
Ｎｃ＝Ｎｔ−Ｎｆ・・・（３）
［４］試料液に対してハロゲンイオンを含む試薬を添加しない無試薬式残留塩素測定方法であって、
試料液に浸漬した金製の検知極と白金製の対極との間に、第１の印加電圧Ｖ１を与えた際に前記検知極と対極との間に流れる第１の酸化還元電流Ｉ（Ｖ１）と、第２の印加電圧Ｖ２を与えた際に前記検知極と対極との間に流れる第２の酸化還元電流Ｉ（Ｖ２）と、第３の印加電圧Ｖ３を与えた際に前記検知極と対極との間に流れる第３の酸化還元電流Ｉ（Ｖ３）とを、各々測定し、
前記第１の印加電圧Ｖ１は、７３０〜７７０ｍＶの範囲から、第２の印加電圧Ｖ２は７８０〜８２０ｍＶの範囲から、第３の印加電圧Ｖ３は８３０〜８７０ｍＶの範囲から、各々選択し、
下記式（１）に基づき、前記試料液の遊離残留塩素濃度Ｎｆを求めることを特徴とする無試薬式残留塩素測定方法。
Ｎｆ＝Ａ×Ｉ（Ｖ１）＋Ｂ×Ｉ（Ｖ２）＋Ｃ×Ｉ（Ｖ３）＋Ｄ ・・・（１）
（ただし、式（１）において、Ａ、Ｂ、Ｃ、Ｄは定数である。）
［５］さらに、下記式（２）に基づき、前記試料液の全残留塩素濃度Ｎｔを求める［４］に記載の無試薬式残留塩素測定方法。
Ｎｔ＝Ｅ×Ｉ（Ｖ３）＋Ｆ・・・（２）
（ただし、式（２）において、Ｅ、Ｆは定数である。）
［６］さらに、下記式（３）に基づき、前記試料液の結合残留塩素濃度Ｎｃを求める［５］に記載の無試薬式残留塩素測定方法。
Ｎｃ＝Ｎｔ−Ｎｆ・・・（３） As a result of extensive studies to achieve the above-mentioned problems, when measured by a polarographic method using a gold-platinum electrode, free residual chlorine and bound residual chlorine have different polarogram shapes, and therefore the present invention has the following constitution. It was adopted.
[1] A reagentless residual chlorine measuring device which does not add a reagent containing halogen ions to a sample liquid,
A detection electrode made of gold and a counter electrode made of platinum, which are immersed in the sample liquid,
A voltage applying mechanism that sequentially applies a first applied voltage V 1 , a second applied voltage V 2 , and a third applied voltage V 3 between the detection electrode and the counter electrode,
An ammeter for measuring a redox current flowing between the detection electrode and the counter electrode,
And an arithmetic control unit,
The first applied voltage V 1 is in the range of −730 to −770 mV, the second applied voltage V 2 is in the range of −780 to −820 mV, and the third applied voltage V 3 is in the range of −830 to −870 mV. From each,
The ammeter includes a first redox current I (V 1 ) flowing between the detection electrode and the counter electrode when the voltage applying mechanism applies a first applied voltage V 1, and the voltage applying mechanism The second redox current I (V 2 ) flowing between the detection electrode and the counter electrode when the second applied voltage V 2 was applied, and the voltage applying mechanism applied the third applied voltage V 3 . At that time, a third redox current I (V 3 ) flowing between the detection electrode and the counter electrode was measured,
The said control part calculates | requires the free residual chlorine concentration Nf of the said sample liquid based on following formula (1), The reagentless residual chlorine measuring apparatus characterized by the above-mentioned.
Nf = A × I (V 1 ) + B × I (V 2 ) + C × I (V 3 ) + D (1)
(However, in Expression (1), A, B, C, and D are constants.)
[2] The reagentless residual chlorine measuring device according to [1], wherein the arithmetic control unit further obtains the total residual chlorine concentration Nt of the sample liquid based on the following formula (2).
Nt = E × I (V 3 ) + F (2)
(However, in the equation (2), E and F are constants.)
[3] The reagentless residual chlorine measuring device according to [2], wherein the arithmetic control unit further obtains a combined residual chlorine concentration Nc of the sample solution based on the following formula (3).
Nc = Nt-Nf (3)
[4] A reagentless residual chlorine measuring method in which a reagent containing a halogen ion is not added to a sample liquid,
A first redox current I (which flows between the detection electrode and the counter electrode when a first applied voltage V 1 is applied between the detection electrode made of gold and the counter electrode made of platinum immersed in the sample solution) V 1 ), a second redox current I (V 2 ) flowing between the detection electrode and the counter electrode when a second applied voltage V 2 is applied, and a third applied voltage V 3 are applied. At that time, a third redox current I (V 3 ) flowing between the detection electrode and the counter electrode was measured,
The first applied voltage V 1 is selected from the range of 730 to 770 mV, the second applied voltage V 2 is selected from the range of 780 to 820 mV, and the third applied voltage V 3 is selected from the range of 830 to 870 mV. ,
A reagentless residual chlorine measuring method, characterized in that the free residual chlorine concentration Nf of the sample liquid is obtained based on the following formula (1).
Nf = A × I (V 1 ) + B × I (V 2 ) + C × I (V 3 ) + D (1)
(However, in Expression (1), A, B, C, and D are constants.)
[5] Furthermore, the reagentless residual chlorine measuring method according to [4], wherein the total residual chlorine concentration Nt of the sample solution is determined based on the following equation (2).
Nt = E × I (V 3 ) + F (2)
(However, in the equation (2), E and F are constants.)
[6] The reagentless residual chlorine measuring method according to [5], which further determines the combined residual chlorine concentration Nc of the sample solution based on the following formula (3).
Nc = Nt-Nf (3)

本発明の無試薬式残留塩素測定装置及び無試薬式残留塩素測定方法によれば、ハロゲンイオンを含む試薬を用いることなく、かつ、電極を交換することなく、結合残留塩素の妨害を排して遊離残留塩素濃度を、実用に耐える精度で測定可能である。
さらには、ハロゲンイオンを含む試薬を用いることなく、かつ、電極を交換することなくで、遊離残留塩素濃度に加えて、全残留塩素濃度と結合残留塩素濃度も実用に耐える精度で測定可能である。 According to the reagentless residual chlorine measuring apparatus and the reagentless residual chlorine measuring method of the present invention, interference of bound residual chlorine is eliminated without using a reagent containing halogen ions and without exchanging electrodes. It is possible to measure the free residual chlorine concentration with an accuracy that can be practically used.
Further, in addition to the free residual chlorine concentration, the total residual chlorine concentration and the combined residual chlorine concentration can be measured with practical accuracy without using a reagent containing halogen ions and without exchanging the electrode. .

本発明の第１実施形態に係る無試薬式残留塩素測定装置の全体構成図である。FIG. 1 is an overall configuration diagram of a reagentless residual chlorine measuring apparatus according to a first embodiment of the present invention. 本発明の第２実施形態に係る無試薬式残留塩素測定装置におけるセンサ部の断面図である。It is sectional drawing of the sensor part in the reagentless residual chlorine measuring apparatus which concerns on 2nd Embodiment of this invention. 本発明の第３実施形態に係る無試薬式残留塩素測定装置の全体構成図である。It is a whole block diagram of the reagentless residual chlorine measuring apparatus which concerns on 3rd Embodiment of this invention. 本発明の第４実施形態に係る無試薬式残留塩素測定装置におけるセンサ部の断面図である。It is sectional drawing of the sensor part in the reagentless residual chlorine measuring apparatus which concerns on 4th Embodiment of this invention. 本発明の実験例１で得られたポーラログラムである。3 is a polarogram obtained in Experimental Example 1 of the present invention. 本発明の実験例２で得られたポーラログラムである。3 is a polarogram obtained in Experimental Example 2 of the present invention. 遊離残留塩素濃度について、本発明の実験例３で得られた演算値をＤＰＤ値と対比したグラフである。It is a graph which compared the calculated value obtained by Experimental example 3 of the present invention with the DPD value about the free residual chlorine concentration. 本発明の実験例３で得られた遊離残留塩素濃度についてのＤＰＤ値を、酸化還元電流Ｉ（Ｖ１）と対比したグラフである。It is a graph which compared the DPD value about the free residual chlorine concentration obtained in Experimental example 3 of the present invention with the redox current I (V 1 ). 全残留塩素濃度について、本発明の実験例３で得られた検量線である。It is a calibration curve obtained in Experimental Example 3 of the present invention for the total residual chlorine concentration. 遊離残留塩素濃度について、本発明の実験例４で得られた演算値をＤＰＤ値と対比したグラフである。It is a graph which compared the calculated value obtained by Experimental example 4 of the present invention with the DPD value about the free residual chlorine concentration. 全残留塩素濃度について、本発明の実験例４で得られた演算値をＤＰＤ値と対比したグラフである。It is a graph which compared the calculated value obtained by Experimental example 4 of the present invention with the DPD value about the total residual chlorine concentration. 結合残留塩素濃度について、本発明の実験例４で得られた演算値をＤＰＤ値と対比したグラフである。It is a graph which compared the calculated value obtained by Experimental example 4 of the present invention with the DPD value about the combined residual chlorine concentration. 本発明の実験例４で得られた遊離残留塩素濃度についてのＤＰＤ値を、酸化還元電流Ｉ（Ｖ１）と対比したグラフである。It is a graph which compared the DPD value about the free residual chlorine concentration obtained in Experimental example 4 of the present invention with the redox current I (V 1 ). 本発明の実験例４で得られた全残留塩素濃度についてのＤＰＤ値を、酸化還元電流Ｉ（Ｖ１）と対比したグラフである。It is a graph which compared the DPD value about the total residual chlorine concentration obtained in Experimental example 4 of the present invention with the redox current I (V 1 ). 本発明の実験例４で得られた結合残留塩素濃度についてのＤＰＤ値を、酸化還元電流Ｉ（Ｖ１）と対比したグラフである。It is a graph which compared the DPD value about the combined residual chlorine concentration obtained in Experimental example 4 of the present invention with the redox current I (V 1 ).

＜第1実施形態＞
［装置構成］
本発明の第１実施形態に係る無試薬式残留塩素測定装置について図１を用いて説明する。本実施形態の無試薬式残留塩素測定装置は、センサ部１と本体部２０とから概略構成されている。 <First embodiment>
[Device configuration]
A reagentless residual chlorine measuring apparatus according to the first embodiment of the present invention will be described with reference to FIG. The reagentless residual chlorine measuring apparatus of the present embodiment is roughly configured by a sensor unit 1 and a main body unit 20.

センサ部１は、試料液Ｓが導入される測定セル１１、下部が試料液Ｓに浸漬される検知極支持体１２、検知極支持体１２の先端面に取り付けられた検知極１３、下部が試料液Ｓに浸漬された対極支持体１４、対極支持体１４の下端側外周面に取り付けられた対極１５、検知極１３を円運動状に振動させるためのモーター１６、検知極支持体１２を保持する軸受け１７、試料液Ｓ中に投入された検知極１３洗浄用の多数のビーズ１８を有している。なお、測定セル１１には、検知極１３と対極１５との間を仕切るメッシュ状の仕切り板１１ａが設けられており、ビーズ１８が、対極１５側に流出しないようになっている。   The sensor unit 1 includes a measurement cell 11 into which the sample solution S is introduced, a sensing electrode support 12 whose lower part is immersed in the sample solution S, a sensing electrode 13 attached to the tip surface of the sensing electrode support 12, and a lower part is the sample. The counter electrode support 14 immersed in the liquid S, the counter electrode 15 attached to the outer peripheral surface of the lower end side of the counter electrode support 14, the motor 16 for vibrating the detection electrode 13 in a circular motion, and the detection electrode support 12 are held. The bearing 17 has a large number of beads 18 for washing the detection electrode 13 put in the sample solution S. The measuring cell 11 is provided with a mesh-shaped partition plate 11a for partitioning the detection electrode 13 and the counter electrode 15 so that the beads 18 do not flow out to the counter electrode 15 side.

本体部２０は、演算制御部２１、加電圧機構２２、電流計２３、表示装置２４を有している。検知極１３と演算制御部２１との間は配線Ｌ１で、対極１５と演算制御部２１との間は配線Ｌ２で、モーター１６と演算制御部２１との間は配線Ｌ３で各々接続されている。電流計２３は配線Ｌ１の途中に、加電圧機構２２は配線Ｌ２の途中に、各々設けられている。   The main body unit 20 has an arithmetic control unit 21, a voltage applying mechanism 22, an ammeter 23, and a display device 24. A wire L1 is connected between the detection electrode 13 and the arithmetic control unit 21, a wire L2 is connected between the counter electrode 15 and the arithmetic control unit 21, and a wire L3 is connected between the motor 16 and the arithmetic control unit 21. . The ammeter 23 is provided in the middle of the wiring L1, and the voltage applying mechanism 22 is provided in the middle of the wiring L2.

検知極１３は金製である。また、対極１５は白金製である。
ポーラログラフ法に用いられる検知極と対極の組み合わせとしては、種々の組み合わせが考えられるところ、本願発明者は、一対の検知極と対極だけで、遊離残留塩素濃度と結合残留塩素濃度の双方の値を実用に耐える精度で求めることを目的に、種々の検知極と対極の組み合わせで印加電圧を変化させて検討した。その結果、後述の実施例に示すように、金製の検知極と白金製の対極と、特定の異なる３つの電圧を組み合わせた場合に、遊離残留塩素濃度と結合残留塩素濃度の双方の値を実用に耐える精度で求められることを見いだした。 The detection electrode 13 is made of gold. The counter electrode 15 is made of platinum.
As a combination of the detection electrode and the counter electrode used in the polarographic method, various combinations are conceivable, and the present inventor has determined that the values of both the free residual chlorine concentration and the combined residual chlorine concentration can be obtained only by the pair of detection electrode and the counter electrode. For the purpose of obtaining the accuracy with practical use, the applied voltage was changed by various combinations of the detection electrode and the counter electrode and examined. As a result, as shown in Examples described later, when the detection electrode made of gold, the counter electrode made of platinum, and three specific different voltages were combined, both the values of the free residual chlorine concentration and the combined residual chlorine concentration were measured. We have found what is required with an accuracy that can be put to practical use.

検知極支持体１２は傾斜状態に配置されており、その長さ方向中間部所定箇所が軸受け１７によって保持され、軸受け１７による保持箇所を支点として歳差運動できるようになっている。また、検知極支持体１２の基端部１２ａとモーター１６の回転軸１６aは偏心して係合している。そのため、モーター１６の回転軸１６aを回転させることにより基端部１２ａが円運動すると共に、検知極支持体１２の先端部に取り付けられた検知極１３も振動（円運動）するようになっている。また、配線Ｌ１は、検知極支持体１２内を通って軸受け１７による保持箇所近傍から、検知極１３を円運動させても、ねじれたりせずに引き出せるようになっている。   The detection electrode support 12 is arranged in an inclined state, and a predetermined portion in the longitudinal direction intermediate portion thereof is held by a bearing 17, and precession can be performed with the holding portion by the bearing 17 as a fulcrum. The base end 12a of the detection electrode support 12 and the rotary shaft 16a of the motor 16 are eccentrically engaged with each other. Therefore, by rotating the rotary shaft 16a of the motor 16, the base end portion 12a moves circularly, and the detection electrode 13 attached to the tip end portion of the detection electrode support 12 also vibrates (circularly moves). . Further, the wiring L1 can be pulled out from the vicinity of the holding position by the bearing 17 through the inside of the detection electrode support 12 without being twisted even if the detection electrode 13 is circularly moved.

ビーズ１８は、検知極１３の近傍に非固定状態で多数配置されている。ビーズ１８は、振動（円運動）する検知極１３に接触して、検知極１３を研磨するようになっている。ビーズ１８の材質としては、セラミックまたはガラスが好ましい。   A large number of beads 18 are arranged near the detection electrode 13 in a non-fixed state. The bead 18 contacts the vibrating (circular movement) detection electrode 13 and polishes the detection electrode 13. The material of the beads 18 is preferably ceramic or glass.

検知極１３および対極１５は、汚れ成分の組成に応じた薬液を用いて洗浄することかできる。例えば、シュウ酸、塩酸、過酸化水素水などを使用した薬液洗浄を行うことができる。また、オゾン洗浄を行ってもよい。また、薬液洗浄等に代えて、若しくは薬液洗浄等と共に、ブラシ洗浄等の物理洗浄を施してもよい。
また、検知極１３の清浄を保つため、ビーズ１８による機械的研磨に加えて、電解研磨を行うことが好ましい。電解研磨は、検知極と対極との間に測定時とは逆向きに電流が流れるようになっていればよく、適宜周知の方法を採用することができる。
本実施形態の無試薬式残留塩素測定装置は、対極１５や検知極１３の洗浄を行うための自動洗浄機構を備えていてもよい。その場合、定期的な洗浄を自動的に行うことができる。 The detection electrode 13 and the counter electrode 15 can be washed with a chemical solution according to the composition of the stain component. For example, chemical cleaning using oxalic acid, hydrochloric acid, hydrogen peroxide solution or the like can be performed. Also, ozone cleaning may be performed. Physical cleaning such as brush cleaning may be performed instead of or in addition to the chemical cleaning.
Further, in order to keep the detection electrode 13 clean, it is preferable to perform electrolytic polishing in addition to mechanical polishing with the beads 18. Electrolytic polishing may be performed by appropriately applying a well-known method as long as a current flows between the detection electrode and the counter electrode in the direction opposite to that at the time of measurement.
The reagentless type residual chlorine measuring apparatus of this embodiment may include an automatic cleaning mechanism for cleaning the counter electrode 15 and the detection electrode 13. In that case, periodic cleaning can be performed automatically.

加電圧機構２２は、検知極１３と対極１５との間に第１の印加電圧Ｖ１、第２の印加電圧Ｖ２、及び第３の印加電圧Ｖ３を順次与えるようになっている。
電圧を印加する時間は、試料液の特性と応答速度に応じて適宜設定すればよい。一つの値の電圧を印加する時間は、１０〜１２０秒であることが好ましい。
なお、第１の印加電圧Ｖ１、第２の印加電圧Ｖ２、及び第３の印加電圧Ｖ３を与える順番に特に限定はないが、電圧変化によるノイズを排除するために昇順または降順で切り替えて行くことが好ましい。 The voltage applying mechanism 22 is configured to sequentially apply the first applied voltage V 1 , the second applied voltage V 2 , and the third applied voltage V 3 between the detection electrode 13 and the counter electrode 15.
The time for applying the voltage may be appropriately set according to the characteristics of the sample liquid and the response speed. The time for applying the voltage of one value is preferably 10 to 120 seconds.
The order in which the first applied voltage V 1 , the second applied voltage V 2 , and the third applied voltage V 3 are applied is not particularly limited, but switching is performed in ascending or descending order in order to eliminate noise due to voltage change. It is preferable to go.

第１の印加電圧Ｖ１は、−７３０〜−７７０ｍＶの範囲から選択され、−７４０〜−７６０ｍＶの範囲から選択されることが好ましく、−７４５〜−７５５ｍＶの範囲から選択されることがより好ましい。
第２の印加電圧Ｖ２は、−７８０〜−８２０ｍＶの範囲から選択され、−７９０〜−８１０ｍＶの範囲から選択されることが好ましく、−７９５〜−８０５ｍＶの範囲から選択されることがより好ましい。
第３の印加電圧Ｖ３は、−８３０〜−８７０ｍＶの範囲から選択され、−８４０〜−８６０ｍＶの範囲から選択されることが好ましく、−８４５〜−８５５ｍＶの範囲から選択されることがより好ましい。 The first applied voltage V 1 is selected from the range of −730 to −770 mV, preferably selected from the range of −740 to −760 mV, and more preferably selected from the range of −745 to −755 mV. .
The second applied voltage V 2 is selected from the range of −780 to −820 mV, preferably selected from the range of −790 to −810 mV, and more preferably selected from the range of −795 to −805 mV. .
Third applied voltage V 3 of is selected from the range of -830~-870mV, it is preferable to be selected from the range of -840~-860mV, more preferably selected from the range of -845~-855mV .

電流計２３は、検知極１３と対極１５との間に、加電圧機構２２が第１の印加電圧Ｖ１を与えた際に検知極１３と対極１５との間に流れる第１の酸化還元電流Ｉ（Ｖ１）と、加電圧機構２２が第２の印加電圧Ｖ２を与えた際に検知極１３と対極１５との間に流れる第２の酸化還元電流Ｉ（Ｖ２）と、加電圧機構２２が第３の印加電圧Ｖ３を与えた際に検知極１３と対極１５との間に流れる第３の酸化還元電流Ｉ（Ｖ３）とを、各々測定するようになっている。
印加電圧を切り替えた直後は、酸化還元電流の値が不安定になるので、第１〜第３の酸化還元電流は、各々電流値が安定したのを確認してから、測定値として取得することが好ましい。 The ammeter 23 includes a first redox current flowing between the detection electrode 13 and the counter electrode 15 when the voltage applying mechanism 22 applies the first applied voltage V 1 between the detection electrode 13 and the counter electrode 15. I (V 1 ), the second redox current I (V 2 ) flowing between the detection electrode 13 and the counter electrode 15 when the voltage application mechanism 22 applies the second applied voltage V 2, and the applied voltage A third redox current I (V 3 ) that flows between the detection electrode 13 and the counter electrode 15 when the mechanism 22 applies the third applied voltage V 3 is measured.
Immediately after switching the applied voltage, the value of the redox current becomes unstable, so the first to third redox currents should be obtained as measured values after confirming that the current values are stable. Is preferred.

演算制御部２１は、本発明の無試薬式残留塩素測定方法に従い、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）に基づき、遊離残留塩素濃度Ｎｆを求めるようになっている。また、第３の酸化還元電流Ｉ（Ｖ３）に基づき、全残留塩素濃度Ｎｔを求めるようになっている。また、全残留塩素濃度Ｎｔと遊離残留塩素濃度Ｎｆとの差から、結合残留塩素濃度Ｎｃを求めるようになっている。
全残留塩素濃度Ｎｔと遊離残留塩素濃度Ｎｆと結合残留塩素濃度Ｎｃの具体的な求め方については後述する。 The arithmetic control unit 21 uses the reagentless residual chlorine measurement method of the present invention to determine the first redox current I (V 1 ), the second redox current I (V 2 ), and the third redox current. The free residual chlorine concentration Nf is obtained based on I (V 3 ). Further, the total residual chlorine concentration Nt is obtained based on the third redox current I (V 3 ). Further, the combined residual chlorine concentration Nc is calculated from the difference between the total residual chlorine concentration Nt and the free residual chlorine concentration Nf.
The specific method for obtaining the total residual chlorine concentration Nt, the free residual chlorine concentration Nf, and the combined residual chlorine concentration Nc will be described later.

演算制御部２１が求めた全残留塩素濃度Ｎｔと遊離残留塩素濃度Ｎｆと結合残留塩素濃度Ｎｃは、信号Ｄ１として表示装置２４に与えられ、表示装置２４にこれらの濃度が表示されるようになっている。また、これらの濃度は、信号Ｄ２として、外部の記録計、データロガー、メモリ、プリンター、コンピュータ等に伝達されるようになっている。なお、信号Ｄ２は、デジタル信号でもアナログ信号でもよい。また、有線で伝達されてもよいし、無線で伝達されてもよい。   The total residual chlorine concentration Nt, the free residual chlorine concentration Nf, and the combined residual chlorine concentration Nc calculated by the arithmetic control unit 21 are given to the display device 24 as a signal D1, and these concentrations are displayed on the display device 24. ing. Further, these densities are transmitted as a signal D2 to an external recorder, data logger, memory, printer, computer or the like. The signal D2 may be a digital signal or an analog signal. Further, it may be transmitted by wire or wirelessly.

また、演算制御部２１は、電流計２３からの電流値を、外部コンピュータに信号Ｄ２として出力してもよい。その場合、当該外部コンピュータにおいて、本発明の無試薬式残留塩素測定方法に従い、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）に基づき、遊離残留塩素濃度Ｎｆを求めるようにしてもよい。また、当該外部コンピュータにおいて、第３の酸化還元電流Ｉ（Ｖ３）に基づき、全残留塩素濃度Ｎｔを求めるようにしてもよい。また、当該外部コンピュータにおいて、全残留塩素濃度Ｎｔと遊離残留塩素濃度Ｎｆとの差から、結合残留塩素濃度Ｎｃを求めるようにしてもよい。 The arithmetic control unit 21 may output the current value from the ammeter 23 to the external computer as the signal D2. In that case, in the external computer, the first redox current I (V 1 ), the second redox current I (V 2 ), and the third oxidation are used according to the reagentless residual chlorine measuring method of the present invention. The free residual chlorine concentration Nf may be obtained based on the reduction current I (V 3 ). Further, in the external computer, the total residual chlorine concentration Nt may be calculated based on the third redox current I (V 3 ). Further, in the external computer, the combined residual chlorine concentration Nc may be obtained from the difference between the total residual chlorine concentration Nt and the free residual chlorine concentration Nf.

また、演算制御部２１は、電流計２３からの各電流値を、信号Ｄ１として表示装置２４に出力してもよい。その場合、操作者が本発明の無試薬式残留塩素測定方法に従い、表示装置２４らか読み取った各電流値に基づき、遊離残留塩素濃度Ｎｆ等を求めることができる。   Further, the arithmetic control unit 21 may output each current value from the ammeter 23 to the display device 24 as the signal D1. In that case, the operator can obtain the free residual chlorine concentration Nf and the like based on each current value read from the display device 24 according to the reagentless residual chlorine measuring method of the present invention.

演算に用いる酸化還元電流については、温度補正することが好ましい。そのため、本発明の無試薬式残留塩素測定装置は、温度センサを備えることが好ましい。試料液温度が充分に一定に保たれている場合や、要求される測定精度が低い場合は、温度補正は省略してもよい。
温度補正とは、酸化還元電流測定の温度依存性を考慮して、基準温度（例えば２５℃）における酸化還元電流に換算することを意味する。基準温度が２５℃の場合、具体的には以下の式（４）により温度補正を行う。
Ｉ（Ｖ）２５＝Ｉ（Ｖ）t ／(1＋(α×（t−２５）／１００)) ・・・（４）
t：測定時の試料液温度(℃)
Ｉ（Ｖ）t ：試料液温度t℃において得られた電圧Ｖにおける酸化還元電流値
Ｉ（Ｖ）２５：基準温度２５℃で温度補正された電圧Ｖにおける酸化還元電流値
α：１℃当りの電極出力変化量(％) The redox current used for the calculation is preferably temperature-corrected. Therefore, the reagentless residual chlorine measuring apparatus of the present invention preferably includes a temperature sensor. The temperature correction may be omitted when the sample liquid temperature is kept sufficiently constant or when the required measurement accuracy is low.
The temperature correction means converting into the redox current at the reference temperature (for example, 25 ° C.) in consideration of the temperature dependency of the redox current measurement. When the reference temperature is 25 ° C., the temperature is specifically corrected by the following equation (4).
I (V) 25 = I (V) t / (1+ (α × (t-25) / 100)) (4)
t: Temperature of sample liquid at measurement (° C)
I (V) t : redox current value at voltage V obtained at sample liquid temperature t ° C. I (V) 25 : redox current value at voltage V corrected at reference temperature 25 ° C. α: per 1 ° C. Electrode output change (%)

［無試薬式残留塩素測定方法］
測定対象となる試料液Ｓに特に限定はなく、試料液Ｓが水道水である場合の他、臭素（臭素イオンまたは臭素酸）を含む海水である場合や、ボイラー冷却水等の海水を含む場合にも好適に適用できる。
測定にあたって、試料液Ｓには、ハロゲンイオンを含む試薬は添加しない。 [Reagentless residual chlorine measurement method]
There is no particular limitation on the sample liquid S to be measured, and when the sample liquid S is tap water, seawater containing bromine (bromine ion or bromic acid), or seawater such as boiler cooling water is included. Can also be applied suitably.
In the measurement, a reagent containing halogen ions is not added to the sample solution S.

演算制御部２１は、下記式（１）に基づき試料液Ｓの遊離残留塩素濃度Ｎｆを求める。
Ｎｆ＝Ａ×Ｉ（Ｖ１）＋Ｂ×Ｉ（Ｖ２）＋Ｃ×Ｉ（Ｖ３）＋Ｄ ・・・（１）
（ただし、式（１）において、Ａ、Ｂ、Ｃ、Ｄは定数である。）
定数であるＡ、Ｂ、Ｃ、Ｄは、ＤＰＤ法により遊離残留塩素濃度を確認した複数の試料液Ｓについて、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）を測定し、得られた複数の測定データから、重回帰分析と単回帰分析により求めることができる。
複数の試料液Ｓには、遊離残留塩素と、結合残留塩素の各々が異なる試料液Ｓが含まれることが好ましい。 The calculation control unit 21 obtains the free residual chlorine concentration Nf of the sample solution S based on the following equation (1).
Nf = A × I (V 1 ) + B × I (V 2 ) + C × I (V 3 ) + D (1)
(However, in Expression (1), A, B, C, and D are constants.)
The constants A, B, C, and D are the first redox current I (V 1 ) and the second redox current I (for the plurality of sample solutions S whose free residual chlorine concentration was confirmed by the DPD method. V 2 ) and the third oxidation-reduction current I (V 3 ) are measured, and the multiple regression data and the single regression analysis can be obtained from the obtained plurality of measurement data.
It is preferable that the plurality of sample liquids S include sample liquids S in which free residual chlorine and bound residual chlorine are different from each other.

演算制御部２１は、また、下記式（２）に基づき試料液Ｓの全残留塩素濃度Ｎｔを求める。
Ｎｔ＝Ｅ×Ｉ（Ｖ３）＋Ｆ・・・（２）
（ただし、式（２）において、Ｅ、Ｆは定数である。）
定数であるＥ、Ｆは、ＤＰＤ法により遊離残留塩素濃度を確認した複数の試料液Ｓについて、第３の酸化還元電流Ｉ（Ｖ３）を測定した複数の測定データから、重回帰分析と単回帰分析により求めることができる。
複数の試料液Ｓには、遊離残留塩素と、結合残留塩素の各々が異なる試料液Ｓが含まれることが好ましい。
複数の測定データは、前記式（１）に基づき、試料液Ｓの遊離残留塩素濃度Ｎｆを求める際に用いた測定データを使用することが好ましい。 The arithmetic control unit 21 also obtains the total residual chlorine concentration Nt of the sample liquid S based on the following equation (2).
Nt = E × I (V 3 ) + F (2)
(However, in the equation (2), E and F are constants.)
The constants E and F are the multiple regression analysis and the simple regression analysis from the plurality of measurement data obtained by measuring the third redox current I (V 3 ) of the plurality of sample solutions S whose free residual chlorine concentration was confirmed by the DPD method. It can be obtained by regression analysis.
It is preferable that the plurality of sample liquids S include sample liquids S in which free residual chlorine and bound residual chlorine are different from each other.
As the plurality of measurement data, it is preferable to use the measurement data used when obtaining the free residual chlorine concentration Nf of the sample solution S based on the above formula (1).

演算制御部２１は、また、下記式（３）に基づき試料液Ｓの結合残留塩素濃度Ｎｃを求める。
Ｎｃ＝Ｎｔ−Ｎｆ・・・（３）
なお、演算制御部２１は、遊離残留塩素濃度Ｎｆと全残留塩素濃度Ｎｔのみを求めてもよい。また、遊離残留塩素濃度Ｎｆのみを求めてもよい。 The arithmetic control unit 21 also obtains the combined residual chlorine concentration Nc of the sample solution S based on the following equation (3).
Nc = Nt-Nf (3)
The arithmetic control unit 21 may obtain only the free residual chlorine concentration Nf and the total residual chlorine concentration Nt. Alternatively, only the free residual chlorine concentration Nf may be obtained.

＜第２実施形態＞
［装置構成］
本発明の第２実施形態に係る無試薬式残留塩素測定装置は、図１のセンサ部１が、図２に示すセンサ部２に変更された他は、第１実施形態と同じである。 <Second Embodiment>
[Device configuration]
The reagentless residual chlorine measuring apparatus according to the second embodiment of the present invention is the same as the first embodiment except that the sensor unit 1 of FIG. 1 is changed to the sensor unit 2 shown in FIG.

図２はセンサ部２の断面図である。図２に示すセンサ部２は、略円筒状のケース３１が設けられ、このケース３１の一方の開口部には、中心部に軸方向に沿った貫通孔３２ａが穿設されている支持基体３２が固着されている。この支持基体３２の軸方向略中央部には、上下一対の円形の窓３２ｂ、３２ｂが、一方の周面から対向する周面に貫通するように、軸方向と直交して穿設されている。また、その先端近くには凹部３２ｃが周方向に形成され、かつ、その凹部３２ｃの全面にわたって対極３３が巻き付けられている。   FIG. 2 is a sectional view of the sensor unit 2. The sensor unit 2 shown in FIG. 2 is provided with a substantially cylindrical case 31, and a support base 32 in which a through hole 32a is formed in the center of one of the openings of the case 31 along the axial direction. Is stuck. A pair of upper and lower circular windows 32b, 32b are formed in a substantially central portion of the support base 32 in the axial direction so as to penetrate from one peripheral surface to the opposing peripheral surfaces at right angles to the axial direction. . Further, a recess 32c is formed in the circumferential direction near the tip thereof, and a counter electrode 33 is wound around the entire surface of the recess 32c.

また、この対極３３の下方には、支持基体３２の先端を覆うようにしてメッシュからなるキャップ３４が螺合している。また、キャップ３４内には後述する検知極３５を研磨・洗浄するためのビーズ３６が多数収納されている。そして、窓３２ｂを内側から覆う位置に内網３７が設けられ、ビーズ３６の流出を防ぐようになっている。   A cap 34 made of mesh is screwed under the counter electrode 33 so as to cover the tip of the support base 32. In addition, a large number of beads 36 for polishing and cleaning a detection electrode 35 described later are housed in the cap 34. Then, an inner net 37 is provided at a position that covers the window 32b from the inside so as to prevent the beads 36 from flowing out.

ケース３１の内部にはモーター３８が取付けられており、モーター３８の回転軸３８ａには、偏心カップリング４１の上方側に固定されている。偏心カップリング４１は、カップリングケース４２に保持されており、カップリングケース４２は、複数本の支柱４３で支持基体３２の上方に保持されている。
偏心カップリング４１の下方側には、略棒状の連結軸４４が連結されている。回転軸３８ａと連結軸４４とが作る角度は約３度に設定され、モーター３８の駆動により、連結軸４４のカップリングケース４２に連結している部位が円運動を行うようになっている。 A motor 38 is attached to the inside of the case 31, and the rotation shaft 38 a of the motor 38 is fixed above the eccentric coupling 41. The eccentric coupling 41 is held by a coupling case 42, and the coupling case 42 is held above the support base 32 by a plurality of columns 43.
A substantially rod-shaped connecting shaft 44 is connected to the lower side of the eccentric coupling 41. The angle formed by the rotating shaft 38a and the connecting shaft 44 is set to about 3 degrees, and the portion of the connecting shaft 44 connected to the coupling case 42 makes a circular motion by driving the motor 38.

連結軸４４の軸方向中央よりやや下側は、軸受け４５に挿入されている。軸受け４５は、連結軸４４方向に円筒状の筒部４５ａと、この筒部４５ａの下端側周囲において半径方向に広がったフランジ部４５ｂとからなり、ゴム材で形成されている。筒部４５ａは連結軸４４に高い圧力をもって水密な状態で密着している。また、軸受け４５は、その外周面が支持基体３２の内周面に水密に接している。   A portion of the connecting shaft 44 slightly below the center in the axial direction is inserted into the bearing 45. The bearing 45 is composed of a cylindrical tubular portion 45a in the direction of the connecting shaft 44 and a flange portion 45b radially widened around the lower end side of the tubular portion 45a, and is made of a rubber material. The tubular portion 45a is in close contact with the connecting shaft 44 in a watertight state with high pressure. The outer peripheral surface of the bearing 45 is in watertight contact with the inner peripheral surface of the support base 32.

連結軸４４の軸受け４５よりも下端側は、略円筒状の検知極支持体４６の上端側に挿入されている。これにより、検知極支持体４６が連結軸４４の下端側に連結固定され、支持基体３２の貫通孔３２ａ内に垂下されている。検知極支持体４６の下端には、検知極３５が設けられている。
モーター３８の駆動により、連結軸４４のカップリングケース４２に連結している部位が円運動すると、連結軸４４は、フランジ部４５ｂの位置する部位を支点とする歳差運動をする。その結果、連結軸４４に固定された検知極支持体４６の下端に設けられた検知極３５も円運動するようになっている。 The lower end side of the coupling shaft 44 with respect to the bearing 45 is inserted into the upper end side of a substantially cylindrical detection electrode support 46. As a result, the detection electrode support 46 is connected and fixed to the lower end side of the connection shaft 44 and hangs down in the through hole 32 a of the support base 32. The detection electrode 35 is provided at the lower end of the detection electrode support 46.
When the portion of the connecting shaft 44 connected to the coupling case 42 moves circularly by driving the motor 38, the connecting shaft 44 makes a precession movement with the position of the flange portion 45b as a fulcrum. As a result, the detection pole 35 provided at the lower end of the detection pole support 46 fixed to the connecting shaft 44 also moves circularly.

検知極３５のリード線４７は、最終的にはコネクター４８を経由して本体部２０の演算制御部２１に連結されている。また、対極３３は、コネクター４８を経由して本体部２０の演算制御部２１に連結されている。モーター３８も、コネクター４８を経由して本体部２０の演算制御部２１に連結されている。
なお、図２において、リード線４７のコネクター４８近傍の配線については図示を省略する。また、対極３３からコネクター４８迄の配線と、モーター３８からコネクター４８迄の配線についても図示を省略する。
第１実施形態と同様、検知極３５は金製であり、対極３３は白金製である。 The lead wire 47 of the detection electrode 35 is finally connected to the arithmetic and control unit 21 of the main body unit 20 via the connector 48. Further, the counter electrode 33 is connected to the arithmetic control unit 21 of the main body unit 20 via the connector 48. The motor 38 is also connected to the arithmetic and control unit 21 of the main body unit 20 via the connector 48.
In FIG. 2, the wiring of the lead wire 47 near the connector 48 is omitted. Also, the wiring from the counter electrode 33 to the connector 48 and the wiring from the motor 38 to the connector 48 are not shown.
Similar to the first embodiment, the detection electrode 35 is made of gold and the counter electrode 33 is made of platinum.

本実施形態のセンサ部２の下端を試料液Ｓに浸すと、試料液Ｓがキャップ３４と窓３２ｂから流入流出する。これにより、試料液Ｓは検知極３５と接触すると共に、支持基体３２に巻き付けられている対極３３にも接触する。すなわち、検知極３５と対極３３が試料液Ｓに浸漬された状態となる。
なお、試料液Ｓは軸受け４５により、軸受け４５より上方のケース３１内への侵入が阻止されるようになっている。
第２実施形態に係る無試薬式残留塩素測定装置は、第１実施形態に係る無試薬式残留塩素測定装置と同様に遊離残留塩素濃度、全残留塩素濃度、及び結合残留塩素濃度を測定することができる。 When the lower end of the sensor unit 2 of the present embodiment is immersed in the sample solution S, the sample solution S flows in and out through the cap 34 and the window 32b. As a result, the sample solution S comes into contact with the detection electrode 35 and also comes into contact with the counter electrode 33 wound around the support base 32. That is, the detection electrode 35 and the counter electrode 33 are in a state of being immersed in the sample solution S.
The sample solution S is prevented by the bearing 45 from entering the case 31 above the bearing 45.
The reagentless residual chlorine measuring device according to the second embodiment measures free residual chlorine concentration, total residual chlorine concentration, and combined residual chlorine concentration similarly to the reagentless residual chlorine measuring device according to the first embodiment. You can

＜第３実施形態＞
［装置構成］
本発明の第３実施形態に係る無試薬式残留塩素測定装置について図３を用いて説明する。なお、図３において、図１と同様の構成部材には、図１と同一の符号を付してその詳細な説明を省略する。
本実施形態の無試薬式残留塩素測定装置は、センサ部３と本体部２０と送液部５０から概略構成されている。 <Third Embodiment>
[Device configuration]
A reagentless residual chlorine measuring apparatus according to the third embodiment of the present invention will be described with reference to FIG. Note that, in FIG. 3, the same members as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.
The reagentless residual chlorine measuring apparatus of the present embodiment is roughly configured by a sensor unit 3, a main body unit 20, and a liquid feeding unit 50.

センサ部３は、第１実施形態の測定セル１１が、フローセル１９に変更された他は、第１実施形態のセンサ部１と同様である。フローセル１９には、検知極１３と対極１５との間を仕切るメッシュ状の仕切り板１９ａが設けられており、ビーズ１８が、対極１５側に流出しないようになっている。
送液部５０は、フローセル１９に試料液Ｓを送る流入路５１と、フローセル１９から試料液Ｓを排出する排出路５２と、流入路５１に設けられたポンプ５３を有している。
ポンプ５３と演算制御部２１との間は配線Ｌ４で各々接続されている。ポンプ５３は、演算制御部２１からの指示により動作するようになっている。
第３実施形態に係る無試薬式残留塩素測定装置は、フローセル１９内に試料液Ｓを流動させる他は、第１実施形態に係る無試薬式残留塩素測定装置と同様に遊離残留塩素濃度、全残留塩素濃度、及び結合残留塩素濃度を測定することができる。 The sensor unit 3 is the same as the sensor unit 1 of the first embodiment, except that the measurement cell 11 of the first embodiment is changed to the flow cell 19. The flow cell 19 is provided with a mesh-shaped partition plate 19a that partitions the detection electrode 13 and the counter electrode 15 so that the beads 18 do not flow out to the counter electrode 15 side.
The liquid sending part 50 has an inflow path 51 for sending the sample solution S to the flow cell 19, an exhaust path 52 for exhausting the sample solution S from the flow cell 19, and a pump 53 provided in the inflow path 51.
The pump 53 and the arithmetic control unit 21 are connected by a wiring L4. The pump 53 operates according to an instruction from the arithmetic control unit 21.
The reagentless residual chlorine measuring apparatus according to the third embodiment is similar to the reagentless residual chlorine measuring apparatus according to the first embodiment except that the sample solution S is flown in the flow cell 19, and the total residual residual chlorine concentration is The residual chlorine concentration and the combined residual chlorine concentration can be measured.

＜第４実施形態＞
［装置構成］
本発明の第４実施形態に係る無試薬式残留塩素測定装置は、図３のセンサ部３が、図４に示すセンサ部４に変更された他は、第３実施形態と同じである。 <Fourth Embodiment>
[Device configuration]
The reagentless residual chlorine measuring apparatus according to the fourth embodiment of the present invention is the same as the third embodiment except that the sensor unit 3 of FIG. 3 is changed to the sensor unit 4 shown in FIG.

図４はセンサ部４の断面図である。センサ部４は、第２実施形態のセンサ部２に、フローセル６０が追加された構成となっている。図４において、図２と同一の構成部材については、図２と同一の符号を付して、その詳細な説明を省略する。
フローセル６０には、支持基体３２が挿入されている。フローセル６０の上端側内壁と支持基体３２外周の間は、Ｏリング６１を介して液密に固着されている。
フローセル６０の先端部の中央には試料液流入用の試料液流入口６０ａが設けられるとともに、Ｏリング６１近傍の側壁には試料液流出用の試料液流出口６０ｂが設けられている。試料液流入口６０ａには流入路５１が、試料液流出口６０ｂには排出路５２が接続される。 FIG. 4 is a sectional view of the sensor unit 4. The sensor unit 4 has a configuration in which a flow cell 60 is added to the sensor unit 2 of the second embodiment. 4, the same components as those in FIG. 2 are designated by the same reference numerals as those in FIG. 2, and detailed description thereof will be omitted.
The support base 32 is inserted in the flow cell 60. The inner wall of the upper end of the flow cell 60 and the outer periphery of the support base 32 are liquid-tightly fixed via an O-ring 61.
A sample solution inlet 60a for sample solution inflow is provided at the center of the tip of the flow cell 60, and a sample solution outlet 60b for sample solution outflow is provided on the side wall near the O-ring 61. An inflow path 51 is connected to the sample liquid inflow port 60a, and a discharge path 52 is connected to the sample liquid outflow port 60b.

本実施形態のセンサ部４のフローセル６０の試料液流入口６０ａから試料液Ｓを流すと、試料液Ｓの一部がキャップ３４内に侵入して窓３２ｂを介して試料液流出口６０ｂから流出する。これにより、試料液Ｓは検知極３５と接触する。また、試料液Ｓの一部は試料液流入口６０ａから流入した後、支持基体３２の外側を通過して試料液流出口６０ｂから流出する。これにより、試料液Ｓは支持基体３２に巻き付けられている対極３３に接触する。すなわち、フローセル６０の試料液流入口６０ａから試料液Ｓを流すことにより、検知極３５と対極３３が試料液Ｓに浸漬した状態となる。   When the sample liquid S is flown from the sample liquid inlet 60a of the flow cell 60 of the sensor unit 4 of the present embodiment, a part of the sample liquid S enters the cap 34 and flows out from the sample liquid outlet 60b through the window 32b. To do. As a result, the sample solution S comes into contact with the detection electrode 35. Further, a part of the sample solution S flows in from the sample solution inflow port 60a, then passes through the outside of the support base 32, and flows out from the sample solution outflow port 60b. As a result, the sample liquid S comes into contact with the counter electrode 33 wound around the support base 32. That is, by flowing the sample solution S from the sample solution inlet 60a of the flow cell 60, the detection electrode 35 and the counter electrode 33 are immersed in the sample solution S.

第４実施形態に係る無試薬式残留塩素測定装置は、第３実施形態に係る無試薬式残留塩素測定装置と同様に遊離残留塩素濃度、全残留塩素濃度、及び結合残留塩素濃度を測定することができる。   The reagentless residual chlorine measuring device according to the fourth embodiment measures free residual chlorine concentration, total residual chlorine concentration, and combined residual chlorine concentration similarly to the reagentless residual chlorine measuring device according to the third embodiment. You can

＜その他の実施形態＞
上記各実施形態では、検知極に接する試料液を検知極表面に対して積極的に流動させる方法によりポーラログラフ法に必要な拡散層の厚みの再現性を得る方法を採用したが、検知極に接する狭い範囲の試料液の流動を抑制する方法により、拡散層の厚みの再現性を得る方法を採用してもよい。当該方法を採用した装置としては、例えば、特開２０１５−３４７４０号に記載された酸化還元電流測定装置が挙げられる。 <Other embodiments>
In each of the above-described embodiments, the method of obtaining the reproducibility of the thickness of the diffusion layer necessary for the polarographic method by positively flowing the sample liquid in contact with the detection electrode with respect to the surface of the detection electrode is adopted. A method of obtaining the reproducibility of the thickness of the diffusion layer by a method of suppressing the flow of the sample liquid in a narrow range may be adopted. An example of an apparatus adopting the method is the redox current measuring apparatus described in JP-A-2015-34740.

以下、本発明の効果を明らかにするための実験例を示す。
［試験装置］
以下の実験例では、試験装置として、東亜ディーケーケー株式会社製高感度残留塩素計ＣＬＨ−１６１０型（第４実施形態の残留塩素測定装置に白金製温度補償センサを追加したもの）を用いた。
ただし、加電圧機構は、電圧を−１００ｍＶ〜−１０００ｍＶの範囲で任意に設定でき、かつ連続的に変化させられるように改造した。
また、検知極としては直径２ｍｍの金電極を用い、線速度で約１００ｃｍ／ｓが得られる程度の回転を与えた。対極は白金電極とした。 Hereinafter, experimental examples for clarifying the effect of the present invention will be shown.
[Test equipment]
In the following experimental examples, a high-sensitivity residual chlorine meter CLH-1610 manufactured by Toa DKK Co., Ltd. (a residual chlorine measuring device of the fourth embodiment with a platinum temperature compensation sensor added) was used as a test device.
However, the voltage applying mechanism was modified so that the voltage can be arbitrarily set in the range of −100 mV to −1000 mV and can be continuously changed.
Further, a gold electrode having a diameter of 2 mm was used as a detection electrode, and rotation was applied so that a linear velocity of about 100 cm / s was obtained. The counter electrode was a platinum electrode.

［ＤＰＤ値］
各実験例で求めたＤＰＤ値（ＤＰＤ法による測定値）は、水道法施行規則第十七条第二項の規定に従い、以下の試薬を用い、以下の方法により求めた。 [DPD value]
The DPD value (measured value by the DPD method) determined in each experimental example was determined by the following method using the following reagents in accordance with the provisions of Article 17, paragraph 2 of the Water Supply Act Enforcement Regulations.

（ａ）ＤＰＤ試薬
関東化学（株）製ＤＰＤ指示薬（ｃａｔ．Ｎｏ１０４６６）。Ｎ，Ｎ−ジエチル−ｐ−フェニレンジアミン（硫酸塩）の１．０ｇと無水硫酸ナトリウムの２４ｇを混合した試薬。
（ｂ）りん酸緩衝液
関東化学（株）製りん酸緩衝液ＤＰＤ法用（ｃａｔ．Ｎｏ３３０５０）。０．２ｍｏｌ／Ｌりん酸二水素カリウム溶液の１００ｍＬ、及び０．２ｍｏｌ／Ｌ水酸化ナトリウム溶液の３５．４ｍＬを混合した後、これに、１，２−シクロヘキサンジアミン四酢酸（１水塩）の０．１３ｇを溶解させた溶液。 (A) DPD reagent A DPD indicator (cat. No. 10466) manufactured by Kanto Chemical Co., Inc. A reagent obtained by mixing 1.0 g of N, N-diethyl-p-phenylenediamine (sulfate) and 24 g of anhydrous sodium sulfate.
(B) Phosphate buffer solution Phosphate buffer solution manufactured by Kanto Chemical Co., Inc. for DPD method (cat. No. 33050). After mixing 100 mL of a 0.2 mol / L potassium dihydrogen phosphate solution and 35.4 mL of a 0.2 mol / L sodium hydroxide solution, 1,2-cyclohexanediaminetetraacetic acid (monohydrate) was added thereto. A solution in which 0.13 g is dissolved.

（ｃ）遊離残留塩素濃度の測定
りん酸緩衝液２．５ｍｌを、容量５０ｍＬの共栓付き比色管に採り、これにＤＰＤ試薬０．５ｇを加える。次に、試料液を加えて５０ｍＬとし、混和後、呈色を残留塩素標準比色列と側面から比色して、試料液中の遊離残留塩素濃度を求める。 (C) Measurement of Free Residual Chlorine Concentration 2.5 ml of phosphate buffer solution is placed in a colorimetric tube with a stopper having a volume of 50 mL, and 0.5 g of DPD reagent is added thereto. Next, the sample solution is added to make 50 mL, and after mixing, the color is colorimetrically compared with the residual chlorine standard colorimetric series from the side to determine the free residual chlorine concentration in the sample solution.

（ｄ）全残留塩素濃度の測定
上記（ｃ）で発色させた溶液にヨウ化カリウム約０．５ｇを加えて溶かし、約２分間静置後の呈色を残留塩素標準比色列と側面から比色して、試料液中の全残留塩素濃度を求める。
（ｅ）結合残留塩素濃度の測定
全残留塩素濃度と遊離残留塩素濃度との差から、試料液中の結合残留塩素濃度を算定する。 (D) Measurement of Total Residual Chlorine Concentration About 0.5 g of potassium iodide was added to the solution developed in (c) to dissolve it, and the coloration after standing for about 2 minutes was measured from the residual chlorine standard colorimetric series and from the side. Colorimetrically determine the total residual chlorine concentration in the sample solution.
(E) Measurement of combined residual chlorine concentration The combined residual chlorine concentration in the sample liquid is calculated from the difference between the total residual chlorine concentration and the free residual chlorine concentration.

［実験例１］
有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を脱塩素水で希釈して、希釈後の濃度が、約０．５ｍｇ／Ｌ、約１ｍｇ／Ｌ、約１．５ｍｇ／Ｌ、約２．０ｍｇ／Ｌとなる遊離塩素試料液を調製した。
脱塩素水は、水道水を活性炭で処理して、塩素を除去した水（以下の実験例についても同じ）を用いた。 [Experimental Example 1]
A sodium hypochlorite solution having an effective chlorine concentration of about 12% is diluted with dechlorinated water, and the concentration after dilution is about 0.5 mg / L, about 1 mg / L, about 1.5 mg / L, about 2. A free chlorine sample solution of 0 mg / L was prepared.
As dechlorinated water, tap water was treated with activated carbon to remove chlorine (the same applies to the following experimental examples).

上記各試料液について、試験装置を用いて、印加電圧と酸化還元電流との関係を示すポーラログラムを調べた。印加電圧は、掃引速度５０ｍＶ／分で、−１００ｍＶから−１０００ｍＶまで連続的に変化させた。結果を図５に示す。
なお、図５において、Ｆの後に記載した数値はＤＰＤ法による遊離残留塩素濃度であり、Ｃの後に記載した数値は、ＤＰＤ法による結合残留塩素濃度である。例えば、「Ｆ０．４８Ｃ０．０３」は、希釈後の濃度が約０．５ｍｇ／Ｌとなるように調製した試料液であるが、ＤＰＤ法による遊離残留塩素濃度が０．４８ｍｇ／Ｌであり、ＤＰＤ法による結合残留塩素濃度が０．０３ｍｇ／Ｌであったことを示す。 A polarogram showing the relationship between the applied voltage and the redox current was examined for each of the above sample liquids using a test apparatus. The applied voltage was continuously changed from -100 mV to -1000 mV at a sweep rate of 50 mV / min. Results are shown in FIG.
In FIG. 5, the numerical value described after F is the free residual chlorine concentration by the DPD method, and the numerical value after C is the combined residual chlorine concentration by the DPD method. For example, "F0.48C0.03" is a sample solution prepared so that the concentration after dilution is about 0.5 mg / L, but the free residual chlorine concentration by the DPD method is 0.48 mg / L, It shows that the combined residual chlorine concentration by the DPD method was 0.03 mg / L.

図５に示すように、約−６００ｍＶ〜−９００ｍＶの範囲で、プラトー領域（印加電圧が若干変化しても、電流がほとんど変化しない領域）が得られた。プラトー領域は、遊離残留塩素濃度が高いほど高電圧側にシフトする傾向がみられた。   As shown in FIG. 5, a plateau region (a region in which the current hardly changes even when the applied voltage slightly changes) was obtained in the range of about −600 mV to −900 mV. The plateau region tended to shift to the higher voltage side as the concentration of free residual chlorine increased.

［実験例２］
有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約１ｍｇ／Ｌ、約２．０ｍｇ／Ｌ、約３．０ｍｇ／Ｌとなるように脱塩素水で希釈したもの１Ｌに対してアンモニア性窒素の濃度が１０００ｍｇ／Ｌの塩化アンモニウム溶液の０．５ｍＬを添加して、結合塩素試料液を調製した。塩化アンモニウム溶液の添加量は、試料液中のアンモニア性窒素の濃度が約０．５ｍｇ／Ｌとなる量である。 [Experimental Example 2]
Sodium hypochlorite solution with an effective chlorine concentration of about 12% diluted with dechlorinated water so that the concentration after dilution becomes about 1 mg / L, about 2.0 mg / L, about 3.0 mg / L. A combined chlorine sample solution was prepared by adding 0.5 mL of an ammonium chloride solution having an ammoniacal nitrogen concentration of 1000 mg / L to 1 L. The ammonium chloride solution is added in such an amount that the concentration of ammoniacal nitrogen in the sample solution becomes about 0.5 mg / L.

上記各試料液について、調製後６０分間静置し、塩素とアンモニア性窒素が反応するのを待ってから、試験装置を用いて、印加電圧と酸化還元電流との関係を示すポーラログラムを調べた。印加電圧は、掃引速度５０ｍＶ／分で、−１００ｍＶから−１０００ｍＶまで連続的に変化させた。結果を図６に示す。
なお、図６において、Ｆの後に記載した数値とＣの後に記載した数値の意味は図５におけるものと同じである。 Each sample solution was left standing for 60 minutes after the preparation, and after waiting for the reaction between chlorine and ammonia nitrogen, a polarogram showing the relationship between the applied voltage and the redox current was examined using a test apparatus. . The applied voltage was continuously changed from -100 mV to -1000 mV at a sweep rate of 50 mV / min. FIG. 6 shows the results.
In FIG. 6, the meanings of the numerical values described after F and the numerical values described after C are the same as those in FIG.

図６に示すように、プラトー領域は存在せず、従来のように、プラトー領域の電流値に基づき検量線を作成することはできない。
そこで、図５と図６のポーラログラムに明確な差が生じる−７００ｍＶから−９００ｍＶの電流値に基づき重回帰分析と単回帰分析によって、遊離残留塩素の検量線を作成することとした。 As shown in FIG. 6, there is no plateau region, and it is not possible to create a calibration curve based on the current value in the plateau region as in the conventional case.
Therefore, it was decided to create a calibration curve of free residual chlorine by multiple regression analysis and single regression analysis based on the current value of -700 mV to -900 mV in which there is a clear difference between the polarograms of FIGS.

［実験例３］
検量線作成のため、以下の試料液を調製した。
Ｎｏ．１：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約１ｍｇ／Ｌとなるように脱塩素水で希釈した。
Ｎｏ．２：Ｎｏ．１の試料液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌの塩化アンモニウム溶液の０．２ｍＬを添加した。
Ｎｏ．３：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約０．５ｍｇ／Ｌとなるように脱塩素水で希釈した。
Ｎｏ．４：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約０．３ｍｇ／Ｌとなるように脱塩素水で希釈した。
Ｎｏ．５：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約０．３ｍｇ／Ｌとなるように脱塩素水で希釈した。
Ｎｏ．６：Ｎｏ．３の試料液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌの塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．７：Ｎｏ．４の試料液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌの塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．８：Ｎｏ．５の試料液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌの塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．９：脱塩素水を試料液とした。 [Experimental Example 3]
The following sample solutions were prepared for preparing a calibration curve.
No. 1: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 1 mg / L.
No. 2: No. To 1 L of the sample liquid of No. 1, 0.2 mL of ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 3: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 0.5 mg / L.
No. 4: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 0.3 mg / L.
No. 5: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 0.3 mg / L.
No. 6: No. To 1 L of the sample liquid of No. 3, 0.1 mL of ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 7: No. To 1 L of the sample liquid of No. 4, 0.1 mL of ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 8: No. To 1 L of the sample liquid of No. 5, 0.1 mL of ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 9: Dechlorinated water was used as a sample solution.

各試料液について、試験装置を用いて、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）を測定した。
第１の印加電圧Ｖ１は、−７５０ｍＶ、第２の印加電圧Ｖ２は−８００ｍＶ、第３の印加電圧Ｖ３は−８５０ｍＶとした。
また、各試料液についてＤＰＤ法により、遊離残留塩素濃度Ｎｆ、全残留塩素濃度Ｎｔ、結合残留塩素濃度Ｎｃを求めた。 For each sample solution, the first redox current I (V 1 ), the second redox current I (V 2 ) and the third redox current I (V 3 ) were measured using a test device. did.
The first applied voltage V 1 was −750 mV, the second applied voltage V 2 was −800 mV, and the third applied voltage V 3 was −850 mV.
Further, the free residual chlorine concentration Nf, the total residual chlorine concentration Nt, and the combined residual chlorine concentration Nc were determined for each sample solution by the DPD method.

結果を表１に示す。表１において、試料Ｎｏ．２−１は、Ｎｏ．２の試料液を調製（塩化アンモニウム溶液添加）した直後に測定した結果である。また、試料Ｎｏ．２−２は、Ｎｏ．２の試料液を調製（塩化アンモニウム溶液添加）して６０分間静置した後に測定した結果である。
試料Ｎｏ．２−１と試料Ｎｏ．２−２の測定結果から、調製（塩化アンモニウム溶液添加）して６０分経過すれば、塩素とアンモニア性窒素との反応は安定し、ポーラログラムの測定に影響がないことが確認できたのでＮｏ．６〜Ｎｏ．８の試料液については、試料Ｎｏ．２−２と同様に、調製（塩化アンモニウム溶液添加）して６０分間静置した後に測定した。 The results are shown in Table 1. In Table 1, the sample No. 2-1 is No. It is the result of measurement immediately after the preparation of the sample liquid of No. 2 (addition of ammonium chloride solution). In addition, the sample No. No. 2-2 is No. It is the result of measurement after preparing the sample liquid of 2 (addition of ammonium chloride solution) and leaving it to stand for 60 minutes.
Sample No. 2-1 and sample No. From the measurement results of 2-2, it was confirmed that the reaction between chlorine and ammonia nitrogen was stable and there was no effect on the polarogram measurement after 60 minutes had passed since preparation (addition of ammonium chloride solution). ． 6-No. For the sample liquid of No. 8, Sample No. As in 2-2, the measurement was performed (addition of ammonium chloride solution), allowed to stand for 60 minutes, and then measured.

Figure 2020060371
Figure 2020060371

表１の結果に基づき、重回帰分析と単回帰分析を行い、遊離残留塩素濃度Ｎｆを求める前記式（１）の定数を求めたところ、以下の値が得られた。
Ａ＝３．８１６［ｍｇ／Ｌ］／［μＡ］
Ｂ＝−１．６１３［ｍｇ／Ｌ］／［μＡ］
Ｃ＝−１．５４６［ｍｇ／Ｌ］／［μＡ］
Ｄ＝０．１７４２［ｍｇ／Ｌ］
すなわち、遊離残留塩素濃度Ｎｆ［ｍｇ／Ｌ］を求める下記式（１ａ）の検量線が得られた。
Ｎｆ＝３．８１６×Ｉ（Ｖ１）＋（−１．６１３）×Ｉ（Ｖ２）
＋（−１．５４６）×Ｉ（Ｖ３）＋０．１７４２ ・・・（１ａ） Based on the results of Table 1, multiple regression analysis and single regression analysis were performed to determine the constant of the above formula (1) for determining the free residual chlorine concentration Nf, and the following values were obtained.
A = 3.816 [mg / L] / [μA]
B = -1.613 [mg / L] / [μA]
C = -1.546 [mg / L] / [μA]
D = 0.1742 [mg / L]
That is, a calibration curve of the following formula (1a) for obtaining the free residual chlorine concentration Nf [mg / L] was obtained.
Nf = 3.816 × I (V 1 ) + (- 1.613) × I (V 2)
+ (- 1.546) × I ( V 3) +0.1742 ··· (1a)

得られた式（１ａ）に基づき演算して求めた各試料液の遊離残留塩素濃度Ｎｆ（演算値 Ｎｆ）を、ＤＰＤ法により求めた遊離残留塩素濃度Ｎｆ（ＤＰＤ Ｎｆ）と共に、表２に示す。また、演算して求めた各試料液の遊離残留塩素濃度ＮｆをＤＰＤ法により求めた遊離残留塩素濃度Ｎｆと対比したグラフを図７に示す。
表２及び図７に示すように、両者には高い精度で一致した。 Table 2 shows the free residual chlorine concentration Nf (calculated value Nf) of each sample solution calculated by the equation (1a) obtained, together with the free residual chlorine concentration Nf (DPD Nf) calculated by the DPD method. . Further, FIG. 7 shows a graph in which the free residual chlorine concentration Nf of each sample solution obtained by calculation is compared with the free residual chlorine concentration Nf obtained by the DPD method.
As shown in Table 2 and FIG. 7, both coincided with each other with high accuracy.

Figure 2020060371
Figure 2020060371

なお、図８は、ＤＰＤ法により求めた遊離残留塩素濃度Ｎｆ（ＤＰＤ Ｎｆ）を酸化還元電流Ｉ（Ｖ１）と対比したグラフである。図５に示すように、結合残留塩素をほとんど含まない試料液であれば、印加電圧−７５０ｍＶ付近で良好なプラトー領域が得られるが、印加電圧−７５０ｍＶで得られる酸化還元電流だけで遊離残留塩素濃度を求めようとすると、結合残留塩素による誤差が大きく、充分な精度が得られないことが確認できた。 Note that FIG. 8 is a graph comparing the free residual chlorine concentration Nf (DPD Nf) determined by the DPD method with the redox current I (V 1 ). As shown in FIG. 5, a sample solution containing almost no residual residual chlorine gives a good plateau region near an applied voltage of −750 mV, but free residual chlorine is obtained only by the redox current obtained at an applied voltage of −750 mV. It was confirmed that when the concentration was tried to be obtained, sufficient error could not be obtained due to a large error due to combined residual chlorine.

表１の結果に基づき、全残留塩素濃度Ｎｔ度を求める前記式（２）の定数を求めたところ、図９に示すように、以下の値が得られた。
Ｅ＝０．７４６５［ｍｇ／Ｌ］／［μＡ］
Ｆ＝０．０１８７［ｍｇ／Ｌ］
すなわち、全残留塩素濃度Ｎｔ［ｍｇ／Ｌ］を求める下記式（２ａ）の検量線が得られた。
Ｎｔ＝０．７４６５×Ｉ（Ｖ３）＋０．０１８７・・・（２ａ）
図９に示すように、結合残留塩素を含むか否かにかかわらず、全残留塩素濃度Ｎｔは、印加電圧−８５０ｍＶで得られる酸化還元電流と、高い相関関係が得られることが確認できた。 Based on the results of Table 1, the constants of the above formula (2) for obtaining the total residual chlorine concentration Nt degree were determined, and as shown in FIG. 9, the following values were obtained.
E = 0.7465 [mg / L] / [μA]
F = 0.0187 [mg / L]
That is, a calibration curve of the following formula (2a) for obtaining the total residual chlorine concentration Nt [mg / L] was obtained.
Nt = 0.7465 × I (V 3 ) +0.0187 ... (2a)
As shown in FIG. 9, it was confirmed that the total residual chlorine concentration Nt has a high correlation with the redox current obtained at an applied voltage of −850 mV, regardless of whether or not the residual chlorine is contained.

［実験例４］
実験例３で得られた検量線の有用性を確認するため、以下の試料液を調製した。
Ｎｏ．１１：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約０．４ｍｇ／Ｌとなるように脱塩素水で希釈した。この希釈液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌである塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．１２：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約０．８ｍｇ／Ｌとなるように脱塩素水で希釈した。この希釈液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌである塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．１３：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約１．２ｍｇ／Ｌとなるように脱塩素水で希釈した。この希釈液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌである塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．１４：有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、希釈後の濃度が、約１．６ｍｇ／Ｌとなるように脱塩素水で希釈した。この希釈液１Ｌに対して、アンモニア性窒素の濃度が１０００ｍｇ／Ｌである塩化アンモニウム溶液の０．１ｍＬを添加した。
Ｎｏ．２１：海水を試料液とした。
Ｎｏ．２２：Ｎｏ．２１の試料液１Ｌに対して、有効塩素濃度約１２％の次亜塩素酸ナトリウム溶液を、Ｎｏ．２１の試料液で希釈された後の濃度が０．５ｍｇ／Ｌとなるように添加した。 [Experimental Example 4]
In order to confirm the usefulness of the calibration curve obtained in Experimental Example 3, the following sample liquid was prepared.
No. 11: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 0.4 mg / L. To 1 L of this diluted solution, 0.1 mL of an ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 12: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 0.8 mg / L. To 1 L of this diluted solution, 0.1 mL of an ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 13: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 1.2 mg / L. To 1 L of this diluted solution, 0.1 mL of an ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 14: A sodium hypochlorite solution having an effective chlorine concentration of about 12% was diluted with dechlorinated water so that the concentration after dilution was about 1.6 mg / L. To 1 L of this diluted solution, 0.1 mL of an ammonium chloride solution having a concentration of ammoniacal nitrogen of 1000 mg / L was added.
No. 21: Seawater was used as the sample solution.
No. 22: No. For 1 L of the sample liquid of No. 21, a sodium hypochlorite solution having an effective chlorine concentration of about 12% was prepared. 21 was added so that the concentration after diluted with the sample liquid was 0.5 mg / L.

各試料液について、試験装置を用いて、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）を測定した。
第１の印加電圧Ｖ１は、−７５０ｍＶ、第２の印加電圧Ｖ２は−８００ｍＶ、第３の印加電圧Ｖ３は−８５０ｍＶとした。
また、各試料液についてＤＰＤ法により、遊離残留塩素濃度Ｎｆ、全残留塩素濃度Ｎｔ、結合残留塩素濃度Ｎｃを求めた。 For each sample solution, the first redox current I (V 1 ), the second redox current I (V 2 ) and the third redox current I (V 3 ) were measured using a test device. did.
The first applied voltage V 1 was −750 mV, the second applied voltage V 2 was −800 mV, and the third applied voltage V 3 was −850 mV.
Further, the free residual chlorine concentration Nf, the total residual chlorine concentration Nt, and the combined residual chlorine concentration Nc were determined for each sample solution by the DPD method.

また、第１の酸化還元電流Ｉ（Ｖ１）と、第２の酸化還元電流Ｉ（Ｖ２）と、第３の酸化還元電流Ｉ（Ｖ３）に基づき、実験例３で求めた式（１ａ）の検量線、式（２ａ）の検量線、及び式（３）に基づき、演算により、遊離残留塩素濃度Ｎｆ、全残留塩素濃度Ｎｔ、結合残留塩素濃度Ｎｃを求めた。 Further, based on the first redox current I (V 1 ), the second redox current I (V 2 ), and the third redox current I (V 3 ), the formula ( 3 ) obtained in Experimental Example 3 ( Free residual chlorine concentration Nf, total residual chlorine concentration Nt, and combined residual chlorine concentration Nc were calculated by calculation based on the calibration curve of 1a), the calibration curve of equation (2a), and equation (3).

結果を表３に示す。表３において、試料Ｎｏ．１１〜試料Ｎｏ．１４は、試料液を調製（次亜塩素酸ナトリウム溶液を添加）して６０分間静置した後に測定した結果である。試料Ｎｏ．２２−１は、Ｎｏ．２２の試料液を調製（次亜塩素酸ナトリウム溶液を添加）した直後に測定した結果である。また、試料Ｎｏ．２２−２は、Ｎｏ．２２の試料液を調製（次亜塩素酸ナトリウム溶液を添加）して３０分間静置した後に測定した結果である。また、試料Ｎｏ．２２−３は、Ｎｏ．２２の試料液を調製（次亜塩素酸ナトリウム溶液を添加）して６０分間静置した後に測定した結果である。また、試料Ｎｏ．２２−４は、Ｎｏ．２２の試料液を調製（次亜塩素酸ナトリウム溶液を添加）して１２０分間静置した後に測定した結果である。
試料Ｎｏ．２２−１〜試料Ｎｏ．２２−４のデータが各々異なるのは、海水をベースとするＮｏ．２２の試料は、調製後、海水中の成分と塩素とが徐々に反応するためである。 The results are shown in Table 3. In Table 3, the sample No. 11 to Sample No. 14 is a result of measurement after preparing a sample solution (adding a sodium hypochlorite solution) and leaving it to stand for 60 minutes. Sample No. No. 22-1 is No. 22-1. It is the result of measurement immediately after preparing the sample liquid of No. 22 (adding a sodium hypochlorite solution). In addition, the sample No. No. 22-2 is No. It is the result of measuring after preparing the sample liquid of 22 (adding sodium hypochlorite solution) and leaving still for 30 minutes. In addition, the sample No. No. 22-3 is No. It is the result of measuring after preparing the sample liquid of 22 (adding sodium hypochlorite solution) and leaving still for 60 minutes. In addition, the sample No. No. 22-4 is No. It is the result of measuring after preparing the sample liquid of 22 (adding sodium hypochlorite solution) and leaving still for 120 minutes.
Sample No. 22-1 to Sample No. The data of No. 22-4 differ from that of No. 22 based on seawater. This is because the sample of No. 22 gradually reacts with chlorine in the seawater after preparation.

Figure 2020060371
Figure 2020060371

また、各試料液の演算により求めた遊離残留塩素濃度Ｎｆ（演算値 Ｎｆ）を、ＤＰＤ法により求めた遊離残留塩素濃度Ｎｆ（ＤＰＤ Ｎｆ）と対比したグラフを図１０に、演算により求めた全残留塩素濃度Ｎｔ（演算値 Ｎｔ）を、ＤＰＤ法により求めた全残留塩素濃度Ｎｔ（ＤＰＤ Ｎｔ）と対比したグラフを図１１に、演算により求めた結合残留塩素濃度Ｎｃ（演算値 Ｎｃ）を、ＤＰＤ法により求めた結合残留塩素濃度Ｎｃ（ＤＰＤ Ｎｃ）と対比したグラフを図１２に、各々示す。
図１０〜１２において、「ＮＨ４−Ｎベース」として示したデータは、試料Ｎｏ．１１〜試料Ｎｏ．１４のデータである。また、「海水ベース」として示したデータは、試料Ｎｏ．２１、試料Ｎｏ．２２−１〜試料Ｎｏ．２２−４のデータである。 In addition, a graph comparing the free residual chlorine concentration Nf (calculated value Nf) obtained by the calculation of each sample solution with the free residual chlorine concentration Nf (DPD Nf) obtained by the DPD method is shown in FIG. FIG. 11 shows a graph comparing the residual chlorine concentration Nt (calculated value Nt) with the total residual chlorine concentration Nt (DPD Nt) obtained by the DPD method, and the combined residual chlorine concentration Nc (calculated value Nc) obtained by the calculation, FIG. 12 shows graphs comparing with the combined residual chlorine concentration Nc (DPD Nc) obtained by the DPD method.
The data shown as “NH 4 —N base” in FIGS. 11 to Sample No. 14 data. In addition, the data shown as "seawater base" is the sample No. 21, sample No. 22-1 to Sample No. 22-4 is the data.

表３及び図１０〜１２に示すように、「ＮＨ４−Ｎベース」として示した試料液は、様々な濃度で結合残留塩素を含むにもかかわらず、遊離残留塩素濃度Ｎｆ、全残留塩素濃度Ｎｔ、結合残留塩素濃度Ｎｃの総てにおいて、演算値はＤＰＤ値と高い精度で一致していた。
また、「海水ベース」として示したデータも、絶対値のずれは見られたものの、演算値とＤＰＤ値との関係は高い相関関係を示した。
海水を含む試料液については、相関関係は確保できているので、試料Ｎｏ．２２−１〜試料Ｎｏ．２２−４のように、海水を含む試料液に基づいて、定数Ａ〜Ｆを求めることにより、絶対値のずれについて改善することが可能である。 As shown in Table 3 and FIGS. 10 to 12, the sample liquid shown as “NH 4 —N based” contained bound residual chlorine at various concentrations, but the free residual chlorine concentration Nf and the total residual chlorine concentration were The calculated values of all the Nt and the combined residual chlorine concentration Nc coincided with the DPD value with high accuracy.
Also, the data shown as "seawater base" also showed a high correlation between the calculated value and the DPD value, although there was a deviation in the absolute value.
Since the correlation can be secured for the sample liquid containing seawater, the sample No. 22-1 to Sample No. 22-4, it is possible to improve the deviation of the absolute value by obtaining the constants A to F based on the sample liquid containing seawater.

なお、図１３は、ＤＰＤ法により求めた遊離残留塩素濃度Ｎｆ（ＤＰＤ Ｎｆ）を酸化還元電流Ｉ（Ｖ１）と対比したグラフである。また、図１４は、ＤＰＤ法により求めた全残留塩素濃度Ｎｔ（ＤＰＤ Ｎｔ）を酸化還元電流Ｉ（Ｖ１）と対比したグラフであり、図１５は、ＤＰＤ法により求めた結合残留塩素濃度Ｎｃ（ＤＰＤ Ｎｃ）を酸化還元電流Ｉ（Ｖ１）と対比したグラフである。 Note that FIG. 13 is a graph comparing the free residual chlorine concentration Nf (DPD Nf) obtained by the DPD method with the redox current I (V 1 ). FIG. 14 is a graph comparing the total residual chlorine concentration Nt (DPD Nt) determined by the DPD method with the redox current I (V 1 ), and FIG. 15 is the combined residual chlorine concentration Nc determined by the DPD method. 6 is a graph comparing (DPD Nc) with redox current I (V 1 ).

図１３〜１５に示すように、「海水ベース」として示した試料液（試料Ｎｏ．２１、試料Ｎｏ．２２−１〜試料Ｎｏ．２２−４）のデータは、ある程度の相関関係が得られたが、「ＮＨ４−Ｎベース」として示した試料液（試料Ｎｏ．１１〜試料Ｎｏ．１４）のデータは、相関関係が得られず、印加電圧−７５０ｍＶで得られる酸化還元電流だけで遊離残留塩素濃度を求めようとすると、結合残留塩素による誤差が大きく、充分な精度が得られないことが確認できた。 As shown in FIGS. 13 to 15, the data of the sample liquids (Sample No. 21, Sample No. 22-1 to Sample No. 22-4) shown as “seawater base” have a certain degree of correlation. However, the data of the sample liquids (Sample No. 11 to Sample No. 14) shown as “NH 4 —N base” do not have a correlation, and remain free only by the redox current obtained at the applied voltage of −750 mV. It was confirmed that when trying to obtain the chlorine concentration, an error due to the combined residual chlorine was large and sufficient accuracy could not be obtained.

１〜４…センサ部、１１…測定セル、１２…検知極支持体、１３、３５…検知極、
１４…対極支持体、１５、３３…対極、１６、３８…モーター、１７、４５…軸受け、
１８、３６…ビーズ、１９、６０…フローセル、２０…本体部、
２１…演算制御部、２２…加電圧機構、２３…電流計、２４…表示装置、
５０…送液部、５３…ポンプ、Ｓ…試料液 1 to 4 ... Sensor part, 11 ... Measuring cell, 12 ... Detection electrode support, 13, 35 ... Detection electrode,
14 ... Counter electrode support, 15, 33 ... Counter electrode, 16, 38 ... Motor, 17, 45 ... Bearing,
18, 36 ... Beads, 19, 60 ... Flow cell, 20 ... Main body part,
21 ... Arithmetic control unit, 22 ... Voltage applying mechanism, 23 ... Ammeter, 24 ... Display device,
50 ... Liquid sending part, 53 ... Pump, S ... Sample liquid

Claims (6)

試料液に対してハロゲンイオンを含む試薬を添加しない無試薬式残留塩素測定装置であって、
試料液に浸漬される金製の検知極、及び白金製の対極と、
前記検知極と対極との間に、第１の印加電圧Ｖ１、第２の印加電圧Ｖ２、及び第３の印加電圧Ｖ３を順次与える加電圧機構と、
前記検知極と対極との間に流れる酸化還元電流を測定する電流計と、
演算制御部とを具備し、
第１の印加電圧Ｖ１は、−７３０〜−７７０ｍＶの範囲から、第２の印加電圧Ｖ２は−７８０〜−８２０ｍＶの範囲から、第３の印加電圧Ｖ３は−８３０〜−８７０ｍＶの範囲から、各々選択され、
前記電流計は、前記加電圧機構が第１の印加電圧Ｖ１を与えた際に前記検知極と対極との間に流れる第１の酸化還元電流Ｉ（Ｖ１）と、前記加電圧機構が第２の印加電圧Ｖ２を与えた際に前記検知極と対極との間に流れる第２の酸化還元電流Ｉ（Ｖ２）と、前記加電圧機構が第３の印加電圧Ｖ３を与えた際に前記検知極と対極との間に流れる第３の酸化還元電流Ｉ（Ｖ３）とを、各々測定し、
前記演算制御部は、下記式（１）に基づき、前記試料液の遊離残留塩素濃度Ｎｆを求めることを特徴とする無試薬式残留塩素測定装置。
Ｎｆ＝Ａ×Ｉ（Ｖ１）＋Ｂ×Ｉ（Ｖ２）＋Ｃ×Ｉ（Ｖ３）＋Ｄ ・・・（１）
（ただし、式（１）において、Ａ、Ｂ、Ｃ、Ｄは定数である。） A reagentless residual chlorine measuring device which does not add a reagent containing halogen ions to a sample liquid,
A detection electrode made of gold and a counter electrode made of platinum, which are immersed in the sample liquid,
A voltage applying mechanism that sequentially applies a first applied voltage V 1 , a second applied voltage V 2 , and a third applied voltage V 3 between the detection electrode and the counter electrode,
An ammeter for measuring a redox current flowing between the detection electrode and the counter electrode,
And an arithmetic control unit,
The first applied voltage V 1 is in the range of −730 to −770 mV, the second applied voltage V 2 is in the range of −780 to −820 mV, and the third applied voltage V 3 is in the range of −830 to −870 mV. From each,
The ammeter includes a first redox current I (V 1 ) flowing between the detection electrode and the counter electrode when the voltage applying mechanism applies a first applied voltage V 1, and the voltage applying mechanism The second redox current I (V 2 ) flowing between the detection electrode and the counter electrode when the second applied voltage V 2 was applied, and the voltage applying mechanism applied the third applied voltage V 3 . At that time, a third redox current I (V 3 ) flowing between the detection electrode and the counter electrode was measured,
The said control part calculates | requires the free residual chlorine concentration Nf of the said sample liquid based on following formula (1), The reagentless residual chlorine measuring apparatus characterized by the above-mentioned.
Nf = A × I (V 1 ) + B × I (V 2 ) + C × I (V 3 ) + D (1)
(However, in Expression (1), A, B, C, and D are constants.) 前記演算制御部は、さらに、下記式（２）に基づき、前記試料液の全残留塩素濃度Ｎｔを求める請求項１に記載の無試薬式残留塩素測定装置。
Ｎｔ＝Ｅ×Ｉ（Ｖ３）＋Ｆ・・・（２）
（ただし、式（２）において、Ｅ、Ｆは定数である。） The reagentless residual chlorine measuring device according to claim 1, wherein the arithmetic control unit further obtains a total residual chlorine concentration Nt of the sample liquid based on the following equation (2).
Nt = E × I (V 3 ) + F (2)
(However, in the equation (2), E and F are constants.) 前記演算制御部は、さらに、下記式（３）に基づき、前記試料液の結合残留塩素濃度Ｎｃを求める請求項２に記載の無試薬式残留塩素測定装置。
Ｎｃ＝Ｎｔ−Ｎｆ・・・（３） The reagentless residual chlorine measuring apparatus according to claim 2, wherein the arithmetic control unit further obtains a combined residual chlorine concentration Nc of the sample solution based on the following equation (3).
Nc = Nt-Nf (3) 試料液に対してハロゲンイオンを含む試薬を添加しない無試薬式残留塩素測定方法であって、
試料液に浸漬した金製の検知極と白金製の対極との間に、第１の印加電圧Ｖ１を与えた際に前記検知極と対極との間に流れる第１の酸化還元電流Ｉ（Ｖ１）と、第２の印加電圧Ｖ２を与えた際に前記検知極と対極との間に流れる第２の酸化還元電流Ｉ（Ｖ２）と、第３の印加電圧Ｖ３を与えた際に前記検知極と対極との間に流れる第３の酸化還元電流Ｉ（Ｖ３）とを、各々測定し、
前記第１の印加電圧Ｖ１は、７３０〜７７０ｍＶの範囲から、第２の印加電圧Ｖ２は７８０〜８２０ｍＶの範囲から、第３の印加電圧Ｖ３は８３０〜８７０ｍＶの範囲から、各々選択し、
下記式（１）に基づき、前記試料液の遊離残留塩素濃度Ｎｆを求めることを特徴とする無試薬式残留塩素測定方法。
Ｎｆ＝Ａ×Ｉ（Ｖ１）＋Ｂ×Ｉ（Ｖ２）＋Ｃ×Ｉ（Ｖ３）＋Ｄ ・・・（１）
（ただし、式（１）において、Ａ、Ｂ、Ｃ、Ｄは定数である。） A reagentless reagentless residual chlorine measurement method in which a reagent containing halogen ions is not added to a sample solution,
A first redox current I (which flows between the detection electrode and the counter electrode when a first applied voltage V 1 is applied between the detection electrode made of gold and the counter electrode made of platinum immersed in the sample solution) V 1 ), a second redox current I (V 2 ) flowing between the detection electrode and the counter electrode when a second applied voltage V 2 is applied, and a third applied voltage V 3 are applied. At that time, a third redox current I (V 3 ) flowing between the detection electrode and the counter electrode was measured,
The first applied voltage V 1 is selected from the range of 730 to 770 mV, the second applied voltage V 2 is selected from the range of 780 to 820 mV, and the third applied voltage V 3 is selected from the range of 830 to 870 mV. ,
A reagentless residual chlorine measuring method, characterized in that the free residual chlorine concentration Nf of the sample liquid is obtained based on the following formula (1).
Nf = A × I (V 1 ) + B × I (V 2 ) + C × I (V 3 ) + D (1)
(However, in Expression (1), A, B, C, and D are constants.) さらに、下記式（２）に基づき、前記試料液の全残留塩素濃度Ｎｔを求める請求項４に記載の無試薬式残留塩素測定方法。
Ｎｔ＝Ｅ×Ｉ（Ｖ３）＋Ｆ・・・（２）
（ただし、式（２）において、Ｅ、Ｆは定数である。） Furthermore, the reagentless residual chlorine measuring method according to claim 4, wherein the total residual chlorine concentration Nt of the sample liquid is determined based on the following formula (2).
Nt = E × I (V 3 ) + F (2)
(However, in the equation (2), E and F are constants.) さらに、下記式（３）に基づき、前記試料液の結合残留塩素濃度Ｎｃを求める請求項５に記載の無試薬式残留塩素測定方法。
Ｎｃ＝Ｎｔ−Ｎｆ・・・（３） Furthermore, the reagentless residual chlorine measuring method according to claim 5, wherein the combined residual chlorine concentration Nc of the sample solution is obtained based on the following formula (3).
Nc = Nt-Nf (3)
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001349866A (en) * 2000-06-06 2001-12-21 Dkk Toa Corp Apparatus for measuring residual chlorine
WO2013070853A1 (en) * 2011-11-11 2013-05-16 Nanoselect, Inc. Multiple potential based chronoamperometric free chlorine sensors
JP2015034741A (en) * 2013-08-08 2015-02-19 東亜ディーケーケー株式会社 Residual chlorine measuring device and residual chlorine measuring method
JP2018124130A (en) * 2017-01-31 2018-08-09 東亜ディーケーケー株式会社 Device and method for measuring residual chlorine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001349866A (en) * 2000-06-06 2001-12-21 Dkk Toa Corp Apparatus for measuring residual chlorine
WO2013070853A1 (en) * 2011-11-11 2013-05-16 Nanoselect, Inc. Multiple potential based chronoamperometric free chlorine sensors
JP2015034741A (en) * 2013-08-08 2015-02-19 東亜ディーケーケー株式会社 Residual chlorine measuring device and residual chlorine measuring method
JP2018124130A (en) * 2017-01-31 2018-08-09 東亜ディーケーケー株式会社 Device and method for measuring residual chlorine

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