JP6179918B2 - Water quality monitoring method - Google Patents

Description

  The present invention relates to a water quality monitoring method.

  For example, when river water, groundwater, etc. are used for livestock breeding, crop cultivation, etc., when removing the treated water after removing metal from the plating wastewater discharged from the electroplating process, it is included in the water. It is important to continuously monitor the type and content of metals that are produced.

As a method for analyzing a metal component in a liquid, for example, the following methods (i) and (ii) are known.
(I) After collecting the heavy metal contained in the collected liquid sample in a heavy metal adsorption filter, the heavy metal is dried and solidified, and the heavy metal adsorption filter obtained by drying and solidifying the adsorbed heavy metal is applied to a fluorescent X-ray analyzer and applied to the heavy metal A method of analyzing the type and content of a kind (Patent Document 1).
(Ii) After the heavy metal ions in the liquid to be inspected are adsorbed to the heavy metal ion adsorbent accommodated in the case, the case is applied to a fluorescent X-ray analyzer, and the heavy metal is irradiated with fluorescent X-rays from the outside of the case A method for analyzing heavy metal ions adsorbed on an ion adsorbent (Patent Document 2).

JP 2004-93272 A JP 2006-220432 A

However, in the methods (i) and (ii), in order to perform a highly accurate analysis, it is necessary to sufficiently adsorb heavy metals on a heavy metal adsorption filter or a heavy metal ion adsorbent. Therefore, the analysis is intermittent. Become. In particular, in the method (i), since the collected heavy metals need to be dried and solidified, the operation is complicated and takes time.
As described above, in the methods (i) and (ii), it is difficult to continuously quantitate the metal in the liquid, so it is difficult to continuously monitor the quality of the target water in the water flow. Therefore, it is difficult to deal with immediately when the quality of the target water deteriorates.

  The present invention provides a water quality monitoring method capable of easily and continuously monitoring the quality of target water during running water.

  In the water quality monitoring method of the present invention, a part of the target water in the running water is continuously extracted, the fluorescence color changes when the extracted target water and metal ions are combined, and the fluorescence intensity increases when the metal ion concentration increases. In this method, the water quality of the target water is continuously monitored from the fluorescence spectrum and fluorescence intensity of the mixed solution.

The fluorescent coloring reagent is preferably a fluorescent coloring reagent that binds to Zn ²⁺ , Cr ³⁺ , Pb ²⁺ , Cd ^2+, or Hg ²⁺ to increase the fluorescence intensity.
In the water quality monitoring method of the present invention, it is preferable to use in combination a binding suppression technique that inhibits at least one selected from Cu ²⁺ , Fe ^2+, and Fe ³⁺ from binding to the fluorescent coloring reagent.

  According to the water quality monitoring method of the present invention, the water quality of the target water during water flow can be easily and continuously monitored.

It is a schematic block diagram of the wastewater treatment system to which the water quality monitoring method of the present invention is applied. 2 is a graph showing a fluorescence spectrum measured in Example 1. FIG. 2 is a calibration curve showing the relationship between Cr ³⁺ concentration and R value (= F ₅₆₆ / F ₆₅₃ ) in Example 1. 10 is a graph showing measurement results of R value (= F ₅₆₆ / F ₆₅₃ ) in Example 2. It is the graph (concentration range 0-150 microgram / L) which plotted the Zn2 ⁺ density | concentration in Example 3. FIG. It is the graph (concentration range 0-500 microgram / L) which plotted the Zn2 ⁺ density | concentration in Example 3. FIG. 10 is a graph showing measurement results of R value (= F ₅₆₇ / F ₅₃₉ ) in Example 3. 10 is a graph showing the relationship between Zn ²⁺ concentration and (R−R _min ) / (R _max −R) in Example 4.

  In the present specification, the compound represented by the formula (1) is referred to as a compound (1), and the same applies to compounds represented by other formulas.

  In the water quality monitoring method of the present invention, a part of the target water in the running water is continuously extracted, the fluorescence color changes when the extracted target water and metal ions are combined, and the fluorescence intensity increases when the metal ion concentration increases. In this method, the water quality of the target water is continuously monitored from the fluorescence spectrum and fluorescence intensity of the mixed solution.

As a fluorescent coloring reagent, the fluorescence color changes due to the binding of metal ions, and the fluorescence intensity increases as the amount of binding to the metal ions increases. Any material that can be identified as existing in water may be used.
As a fluorescent coloring reagent, a fluorescent dye part that emits fluorescence and a chelate structure part that binds to a metal ion are bound, and when the metal ion is bound to the chelate structure part, the fluorescent color of the fluorescent dye part changes, and the metal A reagent whose fluorescence intensity increases with an increase in the amount of bonds with ions is preferred.

  Examples of the fluorescent dye forming the fluorescent dye portion include fluorescent dyes having 4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene (BODIPY) as a mother nucleus structure. Specific examples of the fluorescent dye include the following compound (A1).

  As the chelate compound forming the chelate structure portion, a chelate compound that coordinates with a metal ion using a lone pair of nitrogen atoms of pyridine is preferable. For example, terpyridine such as the following compound (B1), And dipicolylamine derivatives such as B2).

  Specific examples of the fluorescent coloring reagent include the following compound (1) (BDP-TPY) and the following compound (2) (BDP-DPA).

Compound (1), the fluorescence spectrum is changed selectively in response to Zn ^2+, the fluorescence intensity of the fluorescence maximum wavelength from complex compound (1) and Zn ²⁺ increases. In the absence of Zn ²⁺ , the fluorescence spectrum changes in response to Cd ²⁺ and Hg ²⁺ , and the fluorescence intensity at the fluorescence maximum wavelength derived from the complex of compound (1) and Cd ²⁺ or Hg ²⁺ increases.
Compound (2), the fluorescence spectrum is changed selectively in response to Cr ^3+, the fluorescence intensity of the fluorescence maximum wavelength from complex compound (2) and Cr ³⁺ is increased. When Cr ³⁺ does not exist, the fluorescence spectrum changes in response to Cd ²⁺ , Zn ²⁺ , Fe ²⁺ , Pb ²⁺ , Fe ³⁺ , Hg ²⁺ , and a complex of compound (2) and these metal ions The fluorescence intensity at the fluorescence maximum wavelength derived from the source increases.
As a fluorescent coloring reagent, Zn ²⁺ , Cr ³⁺ , Pb ²⁺ , Cd ^2+, or Hg ²⁺ is effective in terms of water quality management, so that Zn ²⁺ , Cr ³⁺ , Pb ²⁺ , Cd ^2+, or Hg A fluorescent coloring reagent that changes fluorescence color by binding to ²⁺ and increases fluorescence intensity is preferable, and compound (1) and compound (2) are more preferable.

In addition, when Cu ²⁺ , Fe ²⁺ , or Fe ³⁺ is present at a high concentration, the compound (1) is quenched even if Zn ²⁺ or the like is present. In addition, when Cu ²⁺ is present, compound (2) is quenched even if Cr ³⁺ or the like is present. Therefore, when Cu ²⁺ , Fe ²⁺ , and Fe ³⁺ are present in the target water, a binding suppression technique that inhibits binding of at least one selected from Cu ²⁺ , Fe ^2+, and Fe ^{3+ with the} fluorescent coloring reagent is further provided. It is preferable to use together. By using the binding suppression technique, Zn ^{2+ and the} like can be detected even if Cu ²⁺ , Fe ²⁺ , and Fe ³⁺ are present.
Examples of the binding suppression technique include a technique of reacting with a bond that preferentially binds to Cu ²⁺ , Fe ²⁺ , and Fe ³⁺ and separating and removing with a filter. Examples of the bound material include cation exchange resin and activated carbon.

Further, in the present invention, a method in which a part of the target water extracted from the water is extracted and branched into a plurality of parts, and the fluorescence intensity measurement (α) of the measurement sample mixed with the fluorescence coloring reagent and the method for inhibiting the binding of the fluorescence coloring reagent are performed. You may make parallel the measurement ((beta)) of the fluorescence intensity of the measurement sample used together. For example, when using the compound (1) to the water quality monitoring of the subject water presence of Zn ²⁺ is suspected, quenching measured (alpha), as long observed increase in fluorescence intensity measurement (beta), the presence of Zn ²⁺ In addition, the presence of Cu ²⁺ can be detected at the same time.

The method of mixing the fluorescent coloring reagent into the extracted target water is not particularly limited as long as the fluorescence intensity can be measured. For example, a reagent solution in which the fluorescent coloring reagent is dissolved in a solvent is prepared, and the reagent is mixed. The method of mixing a solution is mentioned.
The solvent for dissolving the fluorescent coloring reagent may be any solvent that does not interfere with the measurement of the fluorescence intensity and can dissolve the fluorescent coloring reagent, and examples thereof include acetonitrile.
Moreover, you may mix a buffer solution (Tris-HCl, HEPES, etc.) with the extracted object water as needed.

The content of the fluorescent coloring reagent in the reagent solution may be set constant at an arbitrary concentration at which the fluorescence spectrum and fluorescence intensity can be measured. Under a certain concentration condition, since the ratio between the fluorescent coloring reagent to be bound and the target is determined by the binding constant, the amount of metal ions can be determined from the change in fluorescence spectrum and fluorescence intensity according to the calibration curve.
The concentration of the fluorescent coloring reagent in the measurement solution is preferably 0.1 to 10 μM. If it is “lower” than the lower limit value, the fluorescence intensity is low and measurement is difficult, and if it is “higher” than the upper limit value, the dyes aggregate together and fluorescence quenching occurs, making measurement difficult.
In addition, the concentration of the fluorescent coloring reagent in the measurement solution is preferably 0.1 μM or more, more preferably 1.0 μM or more, from the viewpoint that it is easy to visually judge the water quality.

Hereinafter, an example of an embodiment to which the water quality monitoring method of the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing a wastewater treatment system to which a water quality monitoring method of the present invention is applied. In order from the upstream side, a storage means 10 for temporarily storing wastewater W ₀ , an oxidation treatment means 20, an insolubilization treatment means 30, a membrane separation means 40, a pH adjustment means 50, and a water quality monitoring means 60 are provided. It is configured.

The waste water W ₀ is, for example, waste water (treated water) generated from a metal surface treatment factory such as a plating factory, and is a heavy metal and a compound that forms a metal complex by coordination with the heavy metal (hereinafter referred to as “complex”). Forming compound ").
Examples of heavy metals include Cr, Cu, Zn, Cd, Ni, Hg, Pb, Fe, and Mn.
Complex forming compounds include acidic cleaning components such as citric acid, gluconic acid, oxalic acid, tartaric acid, succinic acid, cyanide and salts thereof; ethylenediaminetetraacetic acid (EDTA), ethylenediamine, triethanolamine, and ammonia (ammonium salt Amines) and the like.

The wastewater treatment by the wastewater treatment system in this example includes an oxidation treatment process for oxidizing the complex-forming compound in the wastewater W ₀ , an insolubilization treatment process for insolubilizing heavy metals in the oxidized wastewater, and an insolubilized wastewater film. It has a membrane separation step for separating, a pH adjustment step for adjusting the pH of filtered water separated from the membrane, and a water quality monitoring step for monitoring the quality of treated water after pH adjustment.

<Oxidation process>
First, the waste water W ₀ is temporarily stored in the storage tank 11 of the storage means 10. Next, the waste water W ₀ stored in the storage tank 11 is transferred to the oxidation tank 21 of the oxidation treatment means 20, and the oxidant is added by the oxidant addition means 22 while stirring with the stirring blade 24, and the complex in the waste water W ₀ is added. The forming compound is decomposed by oxidation treatment.
Examples of the oxidizing agent used in the oxidation treatment step include hypochlorous acid, chlorous acid, perchloric acid or a salt thereof, and hydrogen peroxide.
The oxidizing agent adding means 22 is not particularly limited as long as it can add an oxidizing agent, and examples thereof include an electromagnetic metering pump, a diaphragm pump, and a magnet pump.

In the oxidation treatment step, at the time of all oxidized complex forming compound contained in the wastewater W _0, the addition of an oxidizing agent to the waste water W ₀ stops, it is preferable to suppress the excessive addition of the oxidizing agent. Examples of the method for detecting the end point of addition of the oxidizing agent include monitoring of the oxidation-reduction potential using the water quality meter 23, monitoring of the oxidizing agent concentration, monitoring of the concentration of the complex-forming compound, and the like.
Examples of the water quality meter 23 include an oxidation-reduction potentiometer and an oxidant concentration meter.

Moreover, the oxidation treatment process may include a pH adjustment process for adjusting the pH of the wastewater. As the pH adjusting means, the same means as in the pH adjusting step described later can be adopted. Moreover, it is preferable to adjust pH before adding an oxidizing agent.
4-8 are preferable and, as for pH of the wastewater in an oxidation treatment process, 4-6 are more preferable. Thereby, the oxidizing power by an oxidizing agent can be improved without generating chlorine gas.

<Insolubilization process>
In the insolubilization treatment step, the oxidized waste water W ₀ is transferred to the insolubilization tank 31 of the insolubilization treatment means 30 and added with an insolubilizing agent by the insolubilizing agent addition means 32 while being stirred by the stirring blade 34, thereby causing heavy metals in the waste water W _0. Insolubilize. The insolubilization means that heavy metal ions that are liberated in the waste water W ₀ are precipitated by using a hardly soluble compound (insolubilized product). Here, the insolubilized material means a material having a very low solubility, such as a hydroxide or a sulfide.
As the insolubilization method, there are a hydroxide method using a hydroxylating agent and a sulfide method using a sulfiding agent. In the case of the sulfide method, hydrogen sulfide may be generated, and therefore the hydroxide method is preferable as the insolubilization treatment.

The hydroxide method is a method in which a hydroxylating agent (hydroxide ion) and a target metal are reacted and precipitated as a metal hydroxide having low solubility.
Examples of the hydroxylating agent include sodium hydroxide, sodium carbonate, calcium hydroxide, and magnesium hydroxide. Sodium hydroxide is more preferable because sludge generation is reduced.

The sulfide method is a method in which a sulfiding agent (sulfide ion) and a target metal are reacted and precipitated as a metal sulfide having low solubility.
Examples of the sulfurizing agent include sodium sulfide and hydrogen sulfide.

  The insolubilizing agent adding means 32 is not particularly limited as long as an insolubilizing agent can be added. When the hydroxide method is used, a sodium hydroxide solution storage tank having chemical resistance and an electromagnetic metering pump, diaphragm pump, or magnet pump having chemical resistance are used as the insolubilizing agent adding means 32. When the sulfide method is used, as the insolubilizing agent adding means 32, a sodium sulfide solution storage tank having chemical resistance and an electromagnetic metering pump, diaphragm pump, or magnet pump having chemical resistance are used.

When the insolubilization treatment is performed by the hydroxide method, the pH range in which the solubility of the heavy metal is lowest depends on each metal species. Therefore, in order to increase the removal rate of heavy metals, an insolubilizing agent (hydroxylating agent) is added until the pH reaches the lowest solubility. In that case, the amount of the insolubilizing agent added is controlled by measuring the pH of the waste water W ₀ in the insolubilizing tank 31 with the water quality meter 33. However, the composition and concentration of heavy metals in waste water W ₀ to be supplied to the waste water treatment apparatus, if you are found to be constant at all times, can also be controlled by a certain amount injected insolubilizing agent .
An example of the water quality meter 33 is a pH meter.

<Membrane separation process>
In the membrane separation step, the waste water W ₀ that has been insolubilized is transferred to the membrane separation means 40, and the filtered water W _{1 from} which the insoluble matter has been removed by the filtration membrane 41 and the membrane separation concentrated water W ₂ in which the insoluble matter has been concentrated. Membrane separation.
The membrane separation means 40 in this example is a system in which pressure is applied by a pressure pump P1, and includes a filtration membrane 41.

Examples of the filtration membrane 41 include a hollow fiber membrane, a flat membrane, a tubular membrane, and a monolith type membrane. A hollow fiber membrane is preferable because of its high volume filling rate.
When a hollow fiber membrane is used as the filtration membrane 41, examples of the material include cellulose, polyolefin, polysulfone, polyvinylidene fluoride difluoride (PVDF), and polytetrafluoroethylene (PTFE). Among the materials described above, polyvinylidene fluoride difluoride (PVDF) and polytetrafluoroethylene (PTFE) are preferable as the material for the hollow fiber membrane.
When a monolith type membrane is used as the filtration membrane 41, a ceramic membrane can be used.

As a specific example of the membrane separation means 40, for example, a hollow fiber membrane element made of polyvinylidene difluoride is immersed in a water tank for membrane separation, and the secondary side (filtered water side) of the membrane element is connected to a filtration pump. The thing which was done is mentioned. Further, an aeration means for cleaning the membrane surface is provided below the membrane element.
Filtered water _{W 1} is sent to the pH adjusting step. On the other hand, membrane separation concentrated water W ₂ is usually dehydrated, it is treated as industrial wastes such as dehydrated cake.

<PH adjustment step>
In pH adjustment step, transferring the filtered water _{W 1} to pH adjustment tank 51 of the pH adjusting means 50, the pH of the filtered water _{W 1} is adjusted to pH suitable for discharge into rivers. In particular, when the hydroxide method is used in the insolubilization treatment step, the filtered water W ₁ is usually alkaline, so it is preferable to neutralize it. The filtered water W ₁ whose pH has been adjusted is discharged as treated water W ₃ .
Examples of the pH adjusting agent for neutralization in the pH adjusting step include acids such as hydrochloric acid, sulfuric acid and carbon dioxide. When an excessive amount of acid is added in the pH adjusting step, an alkali such as sodium hydroxide, sodium carbonate, calcium hydroxide, magnesium hydroxide is added to readjust the pH so that it becomes a neutral region.
In addition, since the insolubilized substances are sufficiently removed by the membrane separation step, there is no possibility that heavy metals are redissolved even if the pH of the filtered water W ₁ is neutralized.

<Water quality monitoring process>
A part of the treated water W ₃ (target water) discharged from the pH adjusting means 50 is continuously extracted to the water quality monitoring means 60, and the water quality monitoring means 60 includes the extracted treated water W ₃ and a fluorescent coloring reagent. mixing the reagent solution L _1, the fluorescence spectrum and fluorescence intensity of the resulting mixture is measured. Thus, treated water W can quantify metal ions Zn ²⁺ and the like contained in the _3, the quality of treated water W ₃ for discharging can be continuously monitored.

The water quality monitoring means 60 is not particularly limited as long as it can monitor the withdrawn treated water W ₃ in reagent solution mixture fluorescence spectra and continuously quality fluorescence intensity was measured in a mixture of L _1.
As a specific example of the water quality monitoring means 60, for example, an optical waveguide spectrometer that has an optical waveguide in which a mixed liquid flow path is formed and excitation light is irradiated to the flow path can measure fluorescence intensity. An apparatus may be used. For example, a mixed liquid can be flowed into the channel using a syringe pump or the like. Since the fluorescence emission of the fluorescent coloring reagent usually lasts for more than half a year, continuous water quality monitoring can be performed more simply by using an apparatus using such a fluorescent coloring reagent.
As the water quality monitoring means 60, a known spectrofluorometer or a fluorescence measuring instrument using a known microplate reader may be used. Even when these apparatuses are used, the time required for the measurement may be about several tens of seconds, so that continuous water quality can be easily monitored.

  If water quality deterioration, that is, increase in heavy metal content is confirmed in the water quality monitoring process, the results are fed back to increase the amount of oxidant added in the oxidation treatment process, and the addition of insolubilizer in the insolubilization treatment process. Take measures such as increasing the amount, changing the membrane separation conditions in the membrane separation step, and replacing the separation membrane.

According to the water quality monitoring method of the present invention described above, the water quality of the target water during water flow can be monitored easily and continuously. Therefore, even if the quality of the target water deteriorates, it is possible to respond immediately. In addition, if the amount of the fluorescent reagent used is adjusted, the water quality can be easily judged by visual observation under black light irradiation.
In addition, the form which applies the water quality monitoring method of this invention is not limited to an above described waste water treatment system. For example, when river water, ground water, etc. are used for livestock breeding, crop cultivation, etc., the water quality monitoring method of the present invention is applied in the middle of passing river water, ground water, etc. to breeding place, cultivation place, etc. The water quality may be continuously monitored. In such a case, if the deterioration of water quality is confirmed, it is possible to protect livestock and crops by immediately stopping the supply of water.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
[Preparation of metal ion solution]
The metal ion solution consists of 13 kinds of metal ions (Na ⁺ , Mg ²⁺ , K ⁺ , Ca ²⁺ , Cr ³⁺ , Mn ²⁺ , Fe ²⁺ , Fe ³⁺ , Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , Pb ²⁺ ). Were prepared by dissolving in Tris-HCl or HEPES buffer at various concentrations.

[Measurement of fluorescence spectrum]
Measuring instrument: spectrofluorometer (JASCO, FP-6600 Spectrofluorometer, manufactured by JASCO Corporation).
Excitation wavelength: 525 nm.
Fluorescence measurement wavelength: 300 nm to 800 nm.
Stabilization time: 30 minutes.

[Example 1]
In a 10 mL volumetric flask, a metal ion solution having various Cr ³⁺ concentrations and an acetonitrile solution (1 μM) of the compound (2) (BDP-DPA) as a fluorescent reagent are added, and water and acetonitrile are mixed at a volume ratio of 1: A sample was prepared so as to be 9, and the fluorescence spectrum was measured. The result is shown in FIG.

As shown in FIG. 2, as the Cr ³⁺ concentration increased, the fluorescence intensity at 566 nm, which is the fluorescence maximum wavelength derived from the complex of the compound (2) and Cr ³⁺ , increased.
In addition, an isofluorescent point independent of the Cr ³⁺ concentration was observed at 653 nm. The ratio of the fluorescence intensity F ₅₆₆ at ₅₆₆ nm to the fluorescence intensity F _{653 at 653} nm (R value (= F ₅₆₆ / F ₆₅₃ )) was plotted against the Cr ³⁺ concentration to obtain a sigmoid calibration curve (FIG. 3). ). The quantitative range of Cr ³⁺ was 1.5 to 260 mg / L, and the detection limit was 0.31 mg / L.

[Example 2]
Using an acetonitrile solution (1 μM) of compound (2) and a metal ion solution (1 mM) containing Na ⁺ , a fluorescence spectrum was measured in the same manner as in Example 1, and an R value (= F ₅₆₆ / F ₆₅₃ ) was calculated. did. ^Similarly , Mg ²⁺ , K ⁺ , Ca ²⁺ (above, 1 mM), Mn ²⁺ , Fe ²⁺ , Fe ³⁺ , Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , Pb ²⁺ (above, 500 μM) are also similarly fluorescence spectra. _Was measured, and the R value (= F ₅₆₆ / F ₆₅₃ ) was calculated. Further, after adding a metal ion solution containing Cr ³⁺ to these 12 kinds of solutions so that Cr ³⁺ becomes 500 μM, the fluorescence spectrum is measured in the same manner, and the R value (= F ₅₆₆ / F ₆₅₃ ) is calculated. did. The result is shown in FIG. In FIG. Is an R value (= F ₅₆₆ / F ₆₅₃ ) in the case of Cr ³⁺ only. Cont. Metal ions are not contained before Cr ³⁺ addition in.

As shown in FIG. 4, the R value before and after the addition of Cr ^{3+ in} a solution containing Na ⁺ , Mg ²⁺ , K ⁺ , Ca ²⁺ or Mn ²⁺ is equivalent to the case of Cr ³⁺ alone (Cont. In FIG. 4). R value was obtained. Thus, it was confirmed that alkali metal ions, alkaline earth metal ions, and Mn ²⁺ do not affect the determination of Cr ³⁺ by the compound (2).
Compound (2) responded to Fe ²⁺ , Fe ³⁺ , Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , and Pb ²⁺ . For the solution containing Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , and Pb ²⁺ , the fluorescence spectrum of Cr ³⁺ added was the same as that of Cr ³⁺ alone. Thus, even in the presence of Zn ²⁺ , Cd ²⁺ , Hg ²⁺ and Pb ²⁺ , compound (2) selectively responded to Cr ³⁺ .
Moreover, Cu ^<2+ > showed the quenching effect with respect to the compound (2). Moreover, about Fe ^{< 2+>} and Fe ^{<3+ >} , it became an R value substantially equal to the case of only Cr ^<3+> . From the above results, it was found that when the sample does not contain Cu ²⁺ , Fe ²⁺ , or Fe ³⁺ , Cr ³⁺ can be selectively detected by the compound (2) alone.

[Example 3]
A plurality of road drains during rainy weather were collected, and the Zn ²⁺ concentration was measured for each sample by a method using a fluorescent coloring reagent compound (1) (BDP-TPY) and ICP analysis. In the method using compound (1), an acetonitrile solution (1 μM) of compound (1) (BDP-TPY) is added to the collected sample, and water and acetonitrile are used as a measurement sample so that the volume ratio becomes 1: 1. The Zn ²⁺ concentration was determined by measuring the fluorescence spectrum. The calibration curve was prepared with a solution obtained by adding zinc perchlorate to ultrapure water (milli-Q water). When the compound (1) was bonded to Zn ^2+, the fluorescence intensity at 567 nm, which is the fluorescence maximum wavelength, increased, and an isofluorescent point independent of the Zn ²⁺ concentration was observed at 539 nm.
FIG. 5 (concentration range 0 to 150 μg / L) is a graph plotting the Zn ²⁺ concentration by ICP analysis as the horizontal axis and the dissolved Zn ²⁺ concentration measured using the compound (1) as the vertical axis. The graph plotted as the vertical axis is shown in FIG. 6 (concentration range 0 to 500 μg / L). In addition, each square, circle, triangle, and rhombus plot in FIG. 5 and FIG. 6 means road drainage collected in T city, G city, H city, and O city, respectively.
In addition, a measurement sample for which the R value (= F ₅₆₇ / F ₅₃₉ ) of a Zn-containing solution (10 μM) was obtained using the compound (1) was further added to Cd ²⁺ , Hg ²⁺ (more than 10 μM), Na ⁺ , K ^+. , Ca ²⁺ (above, 1 mM) was added, and the R value (= F ₅₆₇ / F ₅₃₉ ) was determined in the same manner as shown in FIG.

As shown in FIG. 5 and FIG. 6, the Zn ²⁺ concentration obtained using the compound (1) is almost the same as the Zn ²⁺ concentration obtained by ICP analysis, and it is possible to easily measure the Zn ²⁺ concentration with high accuracy. Met. Further, as shown in FIG. 7, the R value of Cd ²⁺ , Hg ²⁺ , Na ⁺ , Mg ²⁺ , K ⁺ , and Ca ²⁺ added to the measurement sample is the R value of the measurement sample containing only Zn before addition. Compound (1) selectively responded to Zn ²⁺ even in the presence of Cd ²⁺ , Hg ²⁺ , Na ⁺ , Mg ²⁺ , K ⁺ , Ca ²⁺ .

[Example 4]
Using each of compound (1) and compound (2), a metal ion solution having various Zn ²⁺ concentrations and an acetonitrile solution (1 μM) of a fluorescent reagent are added so that water and acetonitrile have a mass ratio of 1: 9. A measurement sample was prepared, and a fluorescence spectrum was measured to obtain an R value. FIG. 8 is a graph in which (R−R _min ) / (R _max −R) is calculated and plotted against the Zn ²⁺ concentration for each of the case where the compound (1) is used and the case where the compound (2) is used. Shown in R _min means the minimum value of the R value, and R _max means the maximum value of the R value.

As shown in FIG. 8, Zn ²⁺ can be quantified in both compound (1) and compound (2), and by using compound (1) and compound (2), about 0.1 μM to 5 mM. Zn ²⁺ could be quantified in a wide concentration range.

DESCRIPTION OF SYMBOLS 10 Storage means 20 Oxidation treatment means 30 Insolubilization treatment means 40 Membrane separation means 50 pH adjustment means 60 Water quality monitoring means W ₀ Waste water W ₁ Filtration water W ₂ Membrane separation concentrated water W ₃ Treatment water L ₁ Reagent solution

Claims (4)

The following formula, which is a fluorescent coloring reagent that extracts a part of target water in water continuously, changes the fluorescence color when the extracted target water and metal ions are combined, and increases the fluorescence intensity when the metal ion concentration increases mixing a compound represented by (1), ^Zn 2+ eligible in water from the fluorescence spectrum and fluorescence intensity of the mixture is continuously monitoring the concentration of ^{Cd 2+} or ^{Hg 2+,} water quality monitoring method.

The following formula, which is a fluorescent coloring reagent that extracts a part of target water in water continuously, changes the fluorescence color when the extracted target water and metal ions are combined, and increases the fluorescence intensity when the metal ion concentration increases The compound represented by (2) is mixed, and Zn in the target water is determined from the fluorescence spectrum and fluorescence intensity of the mixture. ²⁺ , Cr ³⁺ , Pb ²⁺ , Cd ²⁺ Or Hg ²⁺ Water quality monitoring method that continuously monitors the concentration of water.

The following formula, which is a fluorescent coloring reagent that continuously extracts a part of the target water in the water flow, changes the fluorescence color when the metal ions bind to the extracted target water, and increases the fluorescence intensity when the metal ion concentration increases Zn in the target water is mixed with each of the compound represented by (1) and the compound represented by the following formula (2), and the fluorescence spectrum and fluorescence intensity of the mixture are used. ²⁺ Water quality monitoring method that continuously monitors the concentration of water.

The water quality monitoring method according to any one of claims 1 to 3, wherein a binding suppression technique that inhibits at least one selected from Cu ²⁺ , Fe ^2+, and Fe ³⁺ from binding to the fluorescent coloring reagent is used in combination.

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