JPS5926049A - Method for measuring hydrogen peroxide - Google Patents

Abstract

PURPOSE:To measure quickly the concentration of hydrogen peroxide in high sensitivity with a simple constitution, by using an anode which decomposes hydrogen peroxide in contact with it and a cathode which is reduced by hydrogen peroxide, and by measuring an electric current flowing between both electrodes which are brought into contact with a measuring liquid in an alkaline atmosphere. CONSTITUTION:When a sample containing hydrogen peroxide is supplied into a body 7 with a pump 9, a decomposing reaction of hydrogen peroxide takes place on the surface of a platinum anode 5 because a silver oxide cathode 3 and the anode 5 are always brught into contact with an alkaline electrolyte 2, and a reducing reaction of the cathode is brought out by the hydrogen peroxide included in the sample which has reached the cathode 3 through a porous material 1. Accordingly, an electric current corresponding to the concentration of hydrogen peroxide flows between both electrodes 3, 5. The concentration of the hydrogen peroxide is measured quickly with high sensitivity by measuring this electric current with an ammeter 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a highly sensitive method for measuring hydrogen peroxide concentration 1- in a liquid to be measured.

What is the conventional method for measuring hydrogen peroxide concentration? Potential titration method, spectrophotometry method, etc. are known, but both
Because there are 48゜; In addition, when performing high-80° analysis, there are chemiluminescence methods using luminol and fluorescence methods using homovanillic acid, and their sensitivity reaches the PI)b order, but special measures are required for measurement. This requires an optical system and the equipment becomes complicated.

Furthermore, as a standard method of 'IL vapor chemical hydrogen peroxide 71III used in clinical chemistry and food-related fields, a method of measuring the current value flowing between two electrodes to which a constant rtt flow 1 pulse pressure is applied (Japanese Patent Publication No. 45 -35300, etc.) are known.

This method generally selects a platinum electrode for the anode and a silver electric glaze i for the cathode, and applies a pressure of 0.4 to 0.7 V between the anode and the cathode using, for example, a KCl tit M solution. On the anode side HtOt”! (h+2H” +2e
On the IK tui side 02+ 211zO+4e-→4
The oxidation current flowing between both η (oxidation) is measured in response to the concentration of Ih0z.

This method has the advantage of being able to perform 2tllllyJL quickly and does not require special reagents, but the equipment for applying a predetermined voltage is complicated and e! In terms of degree, in general, p p m A-goo or less is measured and k1. '1, and there are some obstructions 1L.

The inventor of the present invention has two articles in mind, quick response, and j7y
As a result of intensive research on the iL method, which is easy to construct and operate, and has high sensitivity, we found that j, si
The liquid to be measured is applied to these two electrodes in an alkaline atmosphere using two electrodes consisting of an anode that releases molecules of hydrogen peroxide by contact with hydrogen peroxide, and a cathode that converts hydrogen peroxide into molecules by contact with hydrogen peroxide. At this time, the above purpose can be effectively achieved by measuring the current flowing between the two poles and determining 41 degrees of hydrogen peroxide in the face to be measured from this current value. These findings led to the present invention.

That is, according to the above method, hydrogen peroxide is catalytically decomposed, for example, on the platinum surface in an alkaline atmosphere, and ljl>t! On the + side ■202→Oz+2) (++
28 ・=(1) reaction occurs, and silver oxide is reduced by hydrogen peroxide, and on the cathode side, AgxO+211zO+2e-〉2Ag
+2011-・(2) A reaction occurs, and at this time, the ↑11 flow flowing between the two poles becomes 1j
By determining the hydrogen peroxide concentration, the hydrogen peroxide concentration can be determined.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a cylindrical porous Zit tube with a bottom made of ceramic or the like, in which an alkaline electrolytic solution 2 and a cathode 8 are each contained. It penetrates through the quality tube 1 and impregnates the surface of the porous VT tube 1 fi':f. Here, cathode 8G;
Chapter 13: In contact with mepal hydrogen oxide, such as silver oxide and silver oxide, J■
The raw material FC is used either as a powder or formed into an appropriate shape such as a solid. In addition, a cathode lead wire 4 made of platinum, silver, etc. is connected to the cathode 1ifj (3 from outside the porous @'1.Also, as the alkaline electrolyte, water r (aqueous potassium oxide solution, water An aqueous sodium oxide solution or the like is preferable, and this quality allows the measurement system to be kept in an alkaline atmosphere with a plf of 9 or higher.

Furthermore, 6 is porous 1! f1 is an anode wrapped around the outer peripheral wall. This sun I]! These include platinum, silver, gold, palladium, rhodium, iridium, lead, bismuth, and manganese.
Iron alloys, nickel, copal), tJm, iron, etc. that decompose on contact with hydrogen peroxide can be used, but
Platinum is particularly preferred in terms of safety and chemical resistance. Further, the shape of the anode can be formed into a linear shape, a plate shape, a porous body shape, etc., and an anode lead wire 6 made of platinum, silver, etc. in the shape of JJ is connected to the anode 5. 7 is a flow, through, electrode body that accommodates the porous tube 1, and is an outer container for sampling and determining the measurement sample in a continuous flow. It is connected to the lead wire 4 and the anode lead wire 6, and measures the current value flowing between the two poles.In this case, 11t, the flow bar 1 is milliampere, microampere, galvanic current 7! 1st class can be used.

In the measuring device with the above configuration, the pump 9
When the sample containing hydrogen chloride is completely fed into the body 7,
Since both the cathode and the first electrode are in contact with the alkaline solution 2, the 3.
The reaction of formula 1) occurs, and the reaction of formula (2) in F) iJ occurs due to the peroxide water wheel in the sample that has passed through the porous tube 1 and reached the cathode 3. A current that is 1 nob per hydrogen oxide concentration flows, and this flowing current (At) is determined by the current 1118, and the hydrogen peroxide concentration is determined from this current &(. The relationship between current value and hydrogen peroxide concentration is shown in the graph of FIG.

This method is different from the conventional method of applying voltage between two poles! 1 formed between A species 1tr, , Iμ ((
, is based on the galvanic principle that utilizes the original action, and in this case [41 addition? (1, Because there is no need for a river, 'J
”> INt can be made into IIJJ, miniaturization is possible,
In addition, even when compared with the method using applied TIE EE, the same or higher output can be obtained, and the jl11 constant at a concentration of lppm or less is output as the A-goo current value of IIA, so dtlχ11 can be directly achieved with a current of 31, and the polarographic Equivalent to or greater than
It is highly sensitive and has wide application possibilities.

FIG. 3 shows another measuring device Kf used in carrying out the measuring method of the present invention, in which the device is configured with a distance +1Q electrode type (11?). In FIG. 8, 1-0 is 0.03μ Total pore size; Rf diaphragm made of polycarbonate or the like with a thickness of 20 to 30 μm] A circle-shaped body with the bottom closed by 1, and an alkaline solution containing, for example, a 1 to 2 N aqueous potassium hydroxide solution inside the body. !-2 people are there,
In this alkaline YIT, l'J' (a product consisting of cathode 3 and platinum made by solidifying one bag of silver into a solid film in a tablet/former in liquid 2) is housed. In order to make the solid film Jt'+ type stable, silver or the like may be mixed into the anode 5. Also, the shape of the anode 5 (the shape of the anode 5 can move freely as long as it does not come into contact with the cathode 3).

- In the device described above, the diaphragm 11 is one that permeates hydrogen silicide, for example, the pore size is 0.03 p, 15<s2
Since it is made of polycarbonate i of 0 to 3071, when Hozoe 10 is inserted into the liquid to be measured 12, hydrogen peroxide in the liquid to be measured 12 permeates through the diaphragm 11 and
When the electrode 3 and the anode 5 come into contact, the reactions of equations (1) and (2) occur, and the sum and flow flowing between the two electrodes at this time are expressed as 't) 1 flow■
18, and the diaphragm 11 is selected appropriately.
There is also little dirt on both tins 1t53.5.

Figure 4 shows the case where the measurement method of the present invention is used in a detector for 70-injection analysis.
and 5 are respectively at predetermined intervals 11 in the gear solution flow path.
A cathode made of silver oxide and a cathode made of platinum are arranged between the two electrodes. Also, 13 is an alkaline electrolyte pump, 14 is a pump injector for introducing the sample, 15 is a carrier liquid pump, 16 is a conductor Ii'7 through which carrier liquid and the like flow.

In the double-sided device, the sample is introduced into the gearier solution in an oscillating manner, and the alkaline Ti
, f, by the laminar liquid pump 13 (for example, 1 to 2 molar water [alkali 1 [9
The solution is fed into the pipe 16, and the sample is placed between the electrodes 3.5 and 3.5 with both electrodes immersed in the alkaline '11L solution.
, and at this time, '11?' flows between the two poles 8.5? , flow to 1'! ? 18. Note that in this case, the alkaline ttt Ffl solution is not held near the electrode and is flowed out together with the carrier solution.

As explained above, the perfW aqueous bed 4 (constant force method) of the present invention uses an I anode that decomposes hydrogen peroxide by contacting it, and an anode that decomposes hydrogen peroxide by contacting it with hydrogen peroxide. The cathode is brought into contact with a +11!l constant solution containing hydrogen peroxide in an alkali atmosphere, and these i+lIJ
By measuring the 11'L flow flowing around the pole, the
Since the structure is configured to determine the degree of hydrogen peroxide in the IllI constant solution, the applied tit pressure is no longer necessary, and the device can be easily
r+ can be singled out, and the nf of this device? , the degree is lonely and has wide application +'+J D'g 1〆L.

4. f) (+ jl't explanation of the drawings) Figure 1 shows the 70-through type used in the practice of the present invention (h) ii.
January (graph showing the relationship between the current value measured using the same device 1'7 and the hydrogen peroxide concentration, Figure 3 is the diaphragm 1Y used in the implementation of the present invention), axial type hydrogen peroxide ? llQ constant device ilt is not shown (1 envelope diagram, (Figure 114 is an lt!f M explanatory diagram showing the lung part in which the over-injection hydrogen measuring device R according to the present invention is incorporated into the 70-injection analysis device.

2...Alkaline '1ic 191' liquid, 3...Cathode, 5...IIM pole, 8...Ammeter, 12...
...Measurement liquid.

Applicant 111 Kagaku n1ki Co., Ltd. Agent Patent attorney Takashi Kojima 9 Figure 3 Applicant Denki Judo Total 0 0.2 (1,40,60,81,0
ppm hyperpharyngeal hydrogen concentration

Claims (1)

[Claims] 1. An anode that decomposes hydrogen peroxide by contacting it and a cathode that reduces it by contacting hydrogen peroxide with a hydrogen peroxide-containing coating in an alkaline atmosphere. A method for determining hydrogen peroxide 4111, characterized in that the concentration of hydrogen peroxide in a liquid to be measured is determined by measuring the current flowing between these two electrodes in contact with the liquid to be measured. 2 The anode is selected from platinum, gold, Ii'1 (, palladium, rhodium, iridium, gL bismuth, manganese-iron alloy, cobalt, copper and iron). Hydrogen peroxide fi
ll+determined method. 3. The method for measuring hydrogen peroxide according to claim 1, wherein the cathode is made of silver oxide or silver chloride. 1. The method for measuring hydrogen peroxide according to claim 1, wherein the anode is made of platinum and the cathode is made of silver cobalt.