JP2000283955A - Method and device for water examination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the presence/absence of a toxious substance by immersing a molecular film of an amphipatic substance or a bitterness substance in a solution to be examined, adding another amphipatic substance or bitterness substance charged to the reverse polarity to the solution to be examined, and immersing the molecular film, and measuring the change in electric potential of both molecular films. SOLUTION: When a molecular film 25 of a probe 22 integrated in a membrane of an amphipatic substance or a bitterness substance with its hydrophilic part toward the surface is immersed in a liquid, the electric potential of the molecular film 25 is changed according to the components in the liquid. The molecular film 25 has the negative charge, and when the film is immersed and a lipid of positive polarity is added to the solution, the lipid is adsorbed by the molecular film 25, and the output voltage of the probe 2 is changed proportional to the quantity of the added lipid. If there is a toxious substance having the negative charge in the solution, it works on the lipid to change the degree of adsorption. The amphipatic or bitterness substance having the polarity reverse to that of the molecular film 25 is added in the liquid, and then, presence/absence of the toxious substance can be judged in a short time based on the change in electric potential of the molecular film 25 before/after addition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for detecting contamination of a toxic substance or the like in a short time and with high sensitivity when inspecting water quality.

[0002]

2. Description of the Related Art Conventionally, when a toxic substance mixed in tap water or the like is detected, a chromatograph using a liquid or gas has been used.

A chromatograph uses a solid or liquid as a stationary phase and a gas or liquid as a developing agent (mobile phase) to move a sample, and utilizes the difference in the adsorptivity or distribution coefficient of each component in the sample. It is a method of separating.

[0004]

However, the analysis method using the chromatograph has a skill in operation,
There is a problem that it takes several hours to analyze one sample.

In particular, in recent years, there has been an increasing need for a system for constantly monitoring water quality so that water pollution due to intentional or accidents can be detected and dealt with at an early stage. The inspection method used could not cope.

An object of the present invention is to solve this problem and to provide a water quality inspection method and a water quality inspection device capable of detecting toxic substances in a short time and with high sensitivity.

[0007]

According to a first aspect of the present invention, there is provided a water quality testing method, comprising: immersing a molecular film of an amphipathic substance or a bitter substance in a liquid to be tested; Measuring the potential of the membrane, adding an amphipathic substance or a bitter substance having a charge of the opposite polarity to the molecular film to the test solution, and measuring the potential of the molecular film of the test solution after the addition. Measuring the change and determining the presence or absence of a toxic substance in the test liquid based on the amount of change in the potential of the molecular membrane are included.

According to a second aspect of the present invention, there is provided a water quality inspection apparatus comprising: a probe (22) having a reference electrode (23); a molecular film (25) of an amphipathic substance or a bitter substance; Voltage detecting means (35) for detecting a potential difference between an electrode and a molecular film, an output voltage when a test target liquid is measured by the probe, and an amphiphilic substance having a charge of a polarity opposite to that of the molecular film Alternatively, a subtracting means (37) for calculating a difference between an output voltage and a difference when a predetermined amount of a bitter substance is added to the test liquid, and a comparing means (37) for comparing a subtraction result of the subtracting means with a preset threshold value. ).

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a water quality inspection apparatus 2 according to the embodiment.
0 is shown.

In FIG. 1, a water quality inspection apparatus 20 includes a container 21 for containing a reference liquid and a liquid to be inspected, and a probe 2.
2 and a voltage detector 35 for detecting the potential difference of the probe 22
Which converts the output of the voltage detector 35 into a digital value
An A / D converter 36, an arithmetic unit 37 that performs an arithmetic operation and a comparison determination process on the output of the A / D converter 36, and a notification device 38 that notifies the determination result of the arithmetic unit 37.

The probe 22 is immersed in a liquid contained in a container 21 and has a reference electrode 23 for outputting a reference potential for measurement and a molecular film 25 of an amphipathic substance or a bitter substance. are doing.

The surface of the reference electrode 23 is formed so that it does not react with lipids in the liquid.
Is covered with a buffer layer 24 fixed with agar, and a lead wire 22a is connected thereto.

The molecular film 25 is made of a base material 2 made of acrylic or the like.
6 is fixed in a state where one side is exposed,
An electrode 28 is provided on the opposite surface of the molecular film 25 via a buffer layer 27 equivalent to the buffer layer 24 of the reference electrode 23, and a lead wire 22b is connected to the electrode 28.

The molecular film 25 is composed of an amphiphilic substance or a bitter substance having a non-polar hydrophobic part and a polar and hydrophilic part, with the hydrophilic part facing the surface. The electric potential of the membrane changes according to the components in the liquid when immersed in the liquid.

FIG. 2 shows a schematic structure of the molecular film 25. In FIG. 2, each molecule 31 has a spherical hydrophilic group 31a.
And a hydrocarbon chain 31b whose atomic arrangement extends long from the hydrophilic group 31a.
Part of the matrix 33 is included in the matrix 33 (surface structure, microscopic structure having a planar spread) of the surface of the membrane member 32 (made of a polymer and a plasticizer described later) so that the 1a side is arranged on the surface side. Form dissolved inside (for example, molecule 31 ')
Housed in.

The molecular film 25 is formed by mixing the above-mentioned lipid molecules, bitter substances, base polymer and plasticizer at a predetermined ratio. For example, polyvinyl chloride (PVC) is used as the polymer, and dioctyl phthalate (DOP), dioctylphenylphosphonate (DOPP) or tricresyl phosphate (T
800 mg mixed with the above lipid molecules and bitter substances using CP) is dissolved in 10 cc of THF, transferred to a flat-bottomed container (for example, a petri dish of 85 mmφ), and placed on a uniform heated plate at about 30 ° C. Then, for 2 hours, the THF is volatilized to obtain a molecular film having a thickness of about 200 μm.

When the probe 22 is immersed in a liquid, the distance between the reference electrode 23 and the molecular film 25 is made constant so that the measurement conditions do not change. May be supported at regular intervals.

The leads 22 a and 22 b of the probe 22 having the molecular film 25 are connected to a voltage detector 35.

The voltage detector 35 is constituted by, for example, a differential amplifier, detects the difference (voltage) between the potential of the reference electrode 23 and the potential of the molecular film 25, and outputs the difference to the A / D converter 36.

The A / D converter 36 converts the output voltage of the voltage detector 35 into a digital value and outputs the digital value to the arithmetic unit 37.

The arithmetic unit 37 is constituted by a microcomputer, and stores an output value of the A / D converter 36 in a memory 37a when receiving a storage instruction M from an operation unit or the like (not shown). Based on the stored value and the output value of the A / D converter 36, calculation for water quality inspection and comparison judgment are performed, and the judgment result is output to the notification device 38.

The notifying device 38 is composed of a lamp, a buzzer, or a communication device for communicating with other devices, etc., and notifies the determination result of the arithmetic device 37 by light or sound, or notifies other devices by a signal. .

In the water quality test of the present invention, the hydrophilic group 31 of each molecule 31 of the molecular film 25 of the probe 22 is used as an additive.
An amphiphile or a bitter substance having a charge of the opposite polarity to the polarity of a is required.

For example, if the molecular film 25 of the probe 22 has a negatively charged dioctyl phosphate (2C
₈ POOH), oleic acid (C ₁₀ COOH), diphenyl phosphoric acid, or lipid molecule, such as a digital alcohol, nicotine, if it is formed by molecules of bitter substances, such as isohumulone, a solute as an additive Trioctylmethyl ammonium chloride (TOM
A), a lipid such as oleylamine is used.

Next, the principle of a water quality inspection method using the water quality inspection device 20 will be described. As described above, the molecular film 25 of the probe 22 has an electric charge. For example, as shown in FIG. 3A, a probe in which the polarity of the molecular film 25 is minus is added to a liquid containing no toxic substance or lipid. When the positive polarity lipid 40 is added in a state where the liquid 22 is immersed, the added lipid 40 is adsorbed on the molecular membrane 25 as shown in FIG. Due to the adsorption of the lipid 40 to the molecular membrane 25, the output voltage of the probe 22 changes with respect to the voltage before addition.

The degree of the adsorption is substantially proportional to the amount of the added lipid 40, and the change in the output voltage is substantially proportional to the amount of the added lipid 40.

However, if a toxic substance 41 having a negative charge such as a complex cyanide or cyanide ion is present in this liquid, as shown in FIG. It has been found that the toxic substance 41 acts to change the degree of adsorption of the lipid 40 to the molecular membrane 25.

In practice, di-n-phosphate having a negative polarity is used.
When a change in the output voltage of the probe with respect to the concentration of ferrocyanide is obtained using a molecular film 25 of decyl (2C ₁₀ POOH) and TOMA having a positive polarity as the lipid 40 to be added, the characteristic A shown in FIG. Obtained.

FIG. 4 shows that the probe 22 is applied to a reference solution such as tap water containing no toxic substances such as ferrocyan and TOMA.
Output voltage when immersed in the reference solution and 100 pp
b, the difference between the output voltage when TOMA was added and the output voltage when ferrocyanide was added to the reference liquid, and the difference between the output voltage when ferrocyanide was added to the reference liquid and 100% TOMA in the liquid containing this ferrocyanide.
The difference from the output voltage when ppb was added was obtained for each ferrocyanide concentration.

This characteristic A indicates that the ferrocyanide concentration is 10%.
lower than the reference voltage R in the range of ppb to 300 ppb,
When the concentration of ferrocyanide exceeds 300 ppb, it becomes higher than the reference voltage R.

That is, there are two effects of ferrocyan on the adsorption of TOMA.
When the concentration of A is equal to or lower than the concentration, the adsorption of TOMA is suppressed by ferrocyanide, and when the concentration of ferrocyanine is sufficiently higher than the concentration of TOMA, the adsorption of TOMA is promoted by ferrocyanide.

Here, the factor that suppresses the adsorption of TOMA by ferrocyanine is that the ferrocyanide having a negative charge and the TOMA having a positive charge are electrically neutralized by being combined with each other and adsorbed on the molecular film 25. It is estimated that the amount to be reduced has decreased.

Although the cause of the promotion of TOMA adsorption by ferrocyanide is not known at this stage, the TOM
In the state where A was not added, almost no difference in the output voltage of the probe was obtained regardless of the ferrocyanide concentration.
It is clear that the characteristic A of No. 1 was brought about by the addition of TOMA.

Here, in FIG. 4, for example, the reference voltage R
Assuming that the threshold value L1 is 0.8 times the threshold voltage L1 and the threshold value L2 is 1.2 times the reference voltage R, the ferrocyan is approximately 30 pp
In the range of b to 200 ppb, the output voltage difference
When the ferrocyan is in the range of 300 ppb or more, the output voltage difference becomes larger than the threshold value L2.
In the range of ppb to 200 ppb and 300 ppb or more, the presence or absence of toxicity can be determined based on whether or not the output voltage difference is between the threshold values L1 and L2.

However, when the ferrocyan is smaller than 20 ppb or near 300 ppb, the output voltage difference is close to the reference voltage R, and whether or not the liquid contains ferrocyan is determined by thresholds L1 and L2. It cannot be determined.

Of these, the detection limit may be set for a range smaller than 20 ppb, but a dead zone is set around 300 ppb.

As one of the methods for eliminating the dead area, there is a method of changing the amount of the lipid 40 to be added.

For example, of the measurement conditions shown in FIG.
When the amount of OMA is halved, for example, as shown in FIG. 5, the reference voltage R 'becomes almost half of the reference voltage R shown in FIG. 4, and the characteristic B of the output voltage difference becomes equal to the reference voltage R'. The concentration of Russian moves to a lower level (around 50 ppb in FIG. 5) than the concentration in FIG. 4 (300 ppb).

Therefore, the amount of TOMA added is 100 p.
The output voltage difference at the time of pb is between threshold values L1 and L2, and the output voltage difference at the time of the addition amount of TOMA is 50 ppb is the threshold value L set with respect to the reference voltage R 'in FIG.
1 '(for example, 0.8R'), L2 '(for example, 1.2
If it is between R ′), it can be determined that ferrocyanide is below the detection limit (no toxicity).

The output voltage difference when the amount of TOMA added is 100 ppb is between the thresholds L1 and L2, and the output voltage difference when the amount of TOMA added is 50 ppb is equal to the thresholds L1 'and L2. ', Or conversely, TO
When the addition amount of MA is 50 ppb, the output voltage difference is between threshold values L1 'and L2', and when the addition amount of TOMA is 100 ppb, the output voltage difference is between threshold values L1 and L2.
If not, it can be determined that ferrocyanide is contained at about 300 ppb or 50 ppb, that is, it is toxic.

The above characteristics A and B are not limited to those of ferrocyan, but are equivalent to neutral oils, for example.

Next, an example of a water quality inspection method utilizing the above principle will be described with reference to the flowchart of FIG.

First, as a previous step, as described above, the specified addition amounts Ka and Kb of the lipid (TOMA) 40 (for example, K
The threshold values L1, L2, L1 ', and L2' predetermined at a = 100 ppb and Kb = 50 ppb) are stored in the memory 37a of the arithmetic unit 37.

Then, the probe 22 is immersed in the liquid to be inspected, and its output voltage V0 is stored in the memory 37a of the arithmetic unit 37 (S1).

Next, the lipid 40 is added to the liquid to be tested in a smaller specified amount Kb, and the output voltage V1 at this time is stored in the memory 37a (S2).

Here, when a first calculation instruction is given to the arithmetic unit 37, the arithmetic unit 37 obtains a voltage difference Va = V1-V0, and this voltage difference Va is between the threshold values L1 'and L2'. It is determined whether or not (S3, S4).

The voltage difference Va is equal to the threshold values L1 ', L1'
If it is not between 2 ', an alarm signal indicating the presence of toxicity is output to the notification device 38 (S5).

The voltage difference Va is equal to the threshold values L1 ', L1'
When it is between 2 ', instruct the addition of lipid 40,
According to this instruction, lipid 40 is in a predetermined amount (Ka-Kb)
Upon receiving the storage instruction after the addition, the output voltage V2 at this time is stored in the memory 37a (S6, S7).

Here, when a second calculation instruction is given to the calculation device 37, the calculation device 37 obtains a voltage difference Vb = V2-V0, and determines whether or not the voltage difference Vb is between the threshold values L1 and L2. Is determined (S8, S9).

The voltage difference Vb is equal to the threshold values L1 and L2.
If not, an alarm signal indicating toxicity is output to the notification device 38 (S10).

When the voltage difference Vb is between the threshold values L1 and L2, a normal signal indicating no toxicity is output to the notification device 38 (S11).

According to this test method, as shown in FIGS. 4 and 5, extremely small amounts of toxic substances up to about 20 ppb can be detected, and lipids and the like can be added to the test liquid. Since a very simple procedure of measuring a change in voltage is sufficient, the presence or absence of a toxic substance can be determined in a short time.

In the above description, a semi-automatic operation that requires an operation of putting the liquid to be inspected in the container 21, immersing the probe 22, adding an additive, and giving a storage instruction or an arithmetic instruction to the arithmetic unit 37. Although the description has been given of the water quality inspection apparatus 20 of the type, it is desirable that the liquid used for drinking, such as tap water, be inspected regularly by a fully automatic water quality inspection apparatus that is not manually operated.

FIG. 7 shows this fully automatic water quality inspection apparatus 50.
Is shown. In this water quality inspection device 50, the drainage device 5 is connected via a solenoid valve 52 from a pipe 51 of the liquid to be inspected.
The liquid to be tested can be injected into the test container 54 having the sample 3, and additives such as lipids can be added to the test container 5 by the addition device 55.
4 and the probe 22 can be moved into and out of the inspection container 54 by the probe moving device 56 or can be moved to the cleaning device 57.

Solenoid valve 52, drainage device 53, addition device 5
5. The probe moving device 56 and the cleaning device 57 are controlled by the arithmetic device 60.

The arithmetic unit 60 is composed of a microcomputer, similarly to the arithmetic unit 37, and controls the A / D converter 36 with the voltage detected by the voltage detector 35 while controlling each unit. And stores it in an internal memory, and performs a calculation and a comparison determination process on the stored value.

FIG. 8 is a flowchart showing the processing procedure of the arithmetic unit 60. Hereinafter, the operation of the water quality inspection device 50 will be described based on this flowchart.

The arithmetic unit 60 starts a timer for a predetermined time for determining the inspection timing, and when the timer expires, opens the solenoid valve 52 and puts the liquid to be inspected into the inspection container 54.
The probe 22 is immersed in the test target liquid in the test container 54 by controlling the probe moving device 56, and the output voltage V0 at this time is stored (S21 to S25).

Next, the adding device 55 is controlled to put the lipid 40 as an additive into the test container 54 by a specified amount Kb, and the output voltage V1 at this time is stored, and the voltage difference Va = V1−
V0 is obtained, and this voltage difference Va is applied to threshold values L1 'and L2'.
Is determined (S26-S29).

Here, the voltage difference Va is equal to the threshold values L1 'and L1'.
If it is not between 2 ', an alarm signal indicating the presence of toxicity is output to the notification device 38 (S30).

Further, when the voltage difference Va is equal to the threshold values L1 'and L
If it is between 2 ′, the addition device 55 is controlled to add a predetermined amount (Ka−Kb) of the lipid 40, and the output voltage V2 at this time is stored (S31, S32).

Then, a voltage difference Vb = V2-V0 is obtained,
It is determined whether or not the voltage difference Vb is between the thresholds L1 and L2 (S33 to S34).

Here, the voltage difference Vb is equal to the threshold values L1 and L2.
If not, an alarm signal indicating toxicity is output, and if the voltage difference Vb is between the thresholds L1 and L2, a normal signal indicating no toxicity is output (S35, S3).
6).

After this determination is completed, the arithmetic unit 60
Controls the probe moving device 56, removes the probe 22 from the test container 54, moves the probe 22 to the cleaning device 57, cleans the probe 22, and drives the drainage device 53 to empty the test container 54 to perform processing. The process returns to S21 and waits for the next inspection timing (S37, S38).

The water quality inspection apparatus 50 fully automated as described above
By using the system, it is possible to constantly monitor the quality of tap water and the like, to quickly detect intentional or accidental contamination of toxic substances, and to take immediate action.

[0066]

As described above, according to the present invention, an amphipathic substance or a bitter substance having a charge opposite in polarity to the molecular film of the probe is added to the test solution, and the potential of the molecular film after the addition is added. The presence or absence of a toxic substance in the liquid to be tested is determined based on the amount of change in.

Therefore, unlike the conventional analyzer, the operation does not require skill, the presence or absence of a toxic substance can be determined with high sensitivity and in a short time, and regular monitoring of water quality can be easily realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a water quality inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic structure of a molecular film;

FIG. 3 is a diagram for explaining the principle of water quality inspection according to the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a concentration of a toxic substance and a measured value when a lipid is added.

FIG. 5 is a characteristic diagram showing the relationship between the concentration of a toxic substance and the measured value when a lipid is added.

FIG. 6 is a flowchart illustrating an inspection procedure performed by the water quality inspection apparatus according to the embodiment.

FIG. 7 is a diagram showing a configuration of an automated water quality inspection device.

FIG. 8 is a flowchart showing an inspection procedure of an automated water quality inspection apparatus.

[Explanation of symbols]

 Reference Signs List 20 water quality inspection device 22 probe 22a, 22b lead wire 23 reference electrode 24 buffer layer 25 molecular film 26 base material 27 buffer layer 28 electrode 29 support material 31 molecule 31a hydrophilic group 31b hydrophobic chain 35 voltage detector 36 A / D converter 37 Arithmetic device 37a Memory 38 Notification device 40 Lipid 41 Toxic substance 50 Water quality inspection device 51 Piping 52 Solenoid valve 53 Drainage device 54 Inspection container 55 Addition device 56 Cleaning device 57 Probe moving device

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[Procedure amendment]

[Submission date] April 21, 1999 (1999.4.2
1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Etsunobu Naito 5-10-27 Minamiazabu, Minato-ku, Tokyo Inside Anritsu Corporation

Claims (2)

[Claims] A step of immersing a molecular film of an amphipathic substance or a bitter substance in a liquid to be tested and measuring the potential of the molecular film; and having a charge of a polarity opposite to that of the molecular film in the liquid to be tested. A step of adding an amphiphilic substance or a bitter substance; a step of measuring a change in the potential of the molecular membrane of the test liquid after the addition; and a toxic substance of the test liquid based on the change in the potential of the molecular membrane. Determining the presence or absence of water. 2. A probe (22) having a reference electrode (23) and a molecular film (25) of an amphipathic substance or a bitter substance.
Voltage detecting means (35) for detecting a potential difference between a reference electrode of the probe and a molecular film; an output voltage when a test target liquid is measured by the probe; and a charge having a polarity opposite to that of the molecular film. Subtraction means (37) for calculating a difference between an output voltage and a difference when an amphipathic substance or a bitter substance having the following formula is added to the liquid to be tested in a predetermined amount; A water quality inspection device comprising comparison means (37) for comparison.