1. A preparation method of vesicle suspension for detecting silver ions is characterized by comprising the following steps:

1) dropwise adding an ethanol solution of 10, 12-pentacosadiynoic acid into an aqueous solution of disodium ethylene diamine tetraacetate under the condition of stirring at room temperature in a dark place to obtain a suspension;

2) placing the suspension obtained in the step 1) at low temperature in a dark place to ensure that the suspension is fully self-assembled;

3) and (3) polymerizing the fully self-assembled suspension obtained in the step 2) under the irradiation of ultraviolet light to obtain the vesicle suspension for detecting silver ions.

2. The method for preparing a vesicle suspension for detecting silver ions according to claim 1, wherein:

in the step 1), the concentration of a 10, 12-pentacosadiynoic acid monomer in the ethanol solution is 1.8-2.2 mmol/L;

the disodium ethylene diamine tetraacetate water solution is prepared by dissolving disodium ethylene diamine tetraacetate solid powder in HEPES buffer solution under the condition of heating and stirring;

wherein the concentration of the ethylene diamine tetraacetic acid disodium is 1-2 mmol/L; the concentration of HEPES buffer solution is 15-20mM, and the pH value is 7.2-7.6.

3. The method for preparing a vesicle suspension for detecting silver ions according to claim 2, characterized in that:

in the step 1), the volume ratio of the ethanol solution of the 10, 12-pentacosadiynoic acid to the aqueous solution of the disodium ethylene diamine tetraacetate is 0.5-1.5: 10.

4. The method for preparing a vesicle suspension for detecting silver ions according to claim 3, wherein:

in the step 2), the low-temperature dark placement means that the mixture is stored at the temperature of 4 +/-0.5 ℃ for 8-12h in the dark.

5. The method for preparing a vesicle suspension for detecting silver ions according to claim 4, wherein:

in the step 3), the ultraviolet irradiation conditions are as follows: irradiating for 5-10min with 254nm ultraviolet light with power of 6W and distance of 10cm from the sample to be measured.

6. The method for preparing a vesicle suspension for detecting silver ions according to claim 5, wherein:

in the step 1), the concentration of a 10, 12-pentacosadiynoic acid monomer in the ethanol solution is 2 mmol/L;

wherein the concentration of the ethylene diamine tetraacetic acid disodium is 2 mmol/L; the concentration of HEPES buffer solution was 20mM, pH 7.4.

7. A vesicle suspension for detecting silver ions, comprising: the preparation method is adopted to prepare the compound of the formula I as shown in any one of claims 1 to 6.

8. A method for detecting silver ions by using the vesicle suspension prepared by the preparation method of any one of claims 1-6, which is characterized by comprising the following steps:

adding a sample to be detected into the vesicle suspension, incubating for 20-25min, and determining the ultraviolet visible absorption spectrum and the fluorescence emission spectrum of the vesicle suspension:

and if the absorption peak at 636-644nm and the absorption peak at 535-545nm in the ultraviolet visible absorption spectrum are obviously reduced, and the fluorescence intensity at 558-562nm and 625-632nm in the fluorescence emission spectrum is obviously increased, determining that the sample to be detected contains silver ions.

9. The method for detecting silver ions according to claim 8, wherein:

the sample to be tested is added to the vesicle suspension, which changes from blue to red.

10. The method for detecting silver ions according to claim 8, wherein:

when the content of the silver ions in the solution to be detected is within the range of 30-400 mu M, the method can also carry out quantitative analysis on the silver ions in the solution to be detected.

Background

Silver and its compounds are widely used in production and life, and excessive silver can seriously harm ecological environment and human health, so it can be used for Ag in environment⁺Fast and accurateThe detection of (A) has very important significance. Existing Ag⁺Detection methods such as spectroscopy, fluorescent probe methods, and electrochemical sensors, etc., often require expensive instruments, specialist operations, time-consuming sample pre-treatment processes, or complex design synthesis processes, and are difficult to implement in-situ detection.

The Polydiacetylene (PDA) is a conjugated polymer with special optical properties, and can generate color conversion from blue to red and change from non-fluorescence to fluorescence under the external stimulation, so that the PDA in the blue state is considered as an ideal metal ion sensor material, and the optical change can be conveniently detected in three modes of naked eye identification, ultraviolet visible absorption spectrum and fluorescence spectrum.

In the research field of PDA-based metal ion sensors, most researchers have adopted chemical modification for the purpose of experimental selective detection: a functional molecule (or group) capable of selectively recognizing certain metal ions is connected to the terminal carboxyl of a commercial monomer PCDA (10, 12-pentacosadiynoic acid monomer for short) commonly used in the detection field. When metal ions are added into the system, specific metal ions can be subjected to coordination combination or chemical combination with the terminal group of the PDA side chain, so that the conjugated structure of the PDA is disturbed, and finally the optical property of the PDA is changed, thereby realizing the purpose of metal ion detection. Such as: chinese patent CN110501316A discloses' a polydiacetylene liposome in water environment with Pb²⁺The visual detection method of (1), reference "Pham, t.c.; kim, y.k.et al.a Selective Colorimetric and Fluorometric chemosensors Based on Conjugated polydiacetates for Cadmium Ion detection 2019,3(11), 1133-.

However, the above method inevitably involves a large amount of organic synthesis, and the reason for analyzing the organic synthesis is mainly as follows:

1) since organic synthesis generally acts on the terminal carboxyl group of the PCDA monomer (structural formula shown below), the functional molecule for recognizing the metal ion should have the ability to selectively bind to the metal ion first and then have reactivity with the terminal carboxyl group of the PCDA monomer. This requires a higher demand for functional molecules, while there are fewer commercial monomers to choose from to meet the above requirements. Therefore, it is common to chemically modify the functional molecule before chemically modifying the PCDA monomer. A large number of organic synthesis processes not only cause harm to human bodies and the environment, but also complicate the method and improve the preparation cost.

2) The procedure for obtaining the polymer PDA from the monomers is as follows, only if the self-assembly of the diacetylene monomers satisfies certain structural parameters (d is aboutAbout 45 deg.C), polymerization can be initiated by conditions such as light; the polymerization reaction has very strict structural parameters for the self-assembled arrangement of monomers. Therefore, even if a functional group is successfully introduced into the PCDA monomer through organic synthesis, the modified monomer may not be self-assembled due to steric hindrance, non-covalent interaction, or the like, or the structural parameters of self-assembly may not meet the requirements of solid-phase polymerization, and if the system cannot be polymerized to obtain stable blue-color PDA, the capability of metal ion detection is lost.

In summary, the development of PDA-based sensors is limited to some extent by the complex organic synthesis.

Disclosure of Invention

The invention aims to provide a method for detecting silver ions, which can avoid a complex organic synthesis process and realize the detection of Ag⁺The method has the advantages of rapid, sensitive and accurate identification and low cost.

In order to achieve the purpose, the technical solution provided by the invention is as follows:

a preparation method of vesicle suspension for detecting silver ions is characterized by comprising the following steps:

1) dropwise adding an ethanol solution of 10, 12-pentacosadienoic acid (PCDA) into an aqueous solution of disodium ethylene diamine tetraacetate (EDTA-2Na) under the condition of stirring at room temperature in a dark place to obtain colorless supramolecular suspension (PCDA/EDTA for short);

2) placing the colorless supramolecular suspension obtained in the step 1) at a low temperature in a dark place to enable the colorless supramolecular suspension to be fully self-assembled; the reason why the suspension obtained in step 1) is placed in the dark at a low temperature is to allow sufficient self-assembly, and it is considered to be an annealing treatment;

3) and (3) polymerizing the colorless suspension obtained in the step 2) under ultraviolet irradiation to obtain blue vesicle suspension for detecting silver ions, namely polydiacetylene vesicle suspension (PDA/EDTA vesicle suspension).

Further, in the step 1), the concentration of the 10, 12-pentacosadiynoic acid monomer in the ethanol solution is 1.8-2.2 mmol/L;

the disodium ethylene diamine tetraacetate water solution is prepared by dissolving disodium ethylene diamine tetraacetate solid powder in HEPES buffer solution under the condition of heating and stirring;

wherein the concentration of the ethylene diamine tetraacetic acid disodium is 1-2 mmol/L; the concentration of HEPES buffer solution is 15-20mM, and the pH value is 7.2-7.6.

Further, in the step 1), the volume ratio of the ethanol solution of the 10, 12-pentacosadiynoic acid to the aqueous solution of the disodium ethylene diamine tetraacetate is 0.5-1.5: 10.

Further, in the step 2), the low-temperature dark placement refers to keeping for 8-12 hours at a temperature of 4 +/-0.5 ℃ in the dark, such as placing in a refrigerator.

Further, in the step 3), the ultraviolet irradiation conditions are as follows: irradiating for 5-10min with 254nm ultraviolet light with power of 6W and distance of 10cm from the sample to be measured.

Further, in the step 1), the concentration of the 10, 12-pentacosadiynoic acid monomer in the ethanol solution is preferably 2 mmol/L;

wherein, the concentration of the ethylene diamine tetraacetic acid disodium is preferably 2 mmol/L; the concentration of the HEPES buffer solution is preferably 20mM, pH 7.4.

The invention also provides a vesicle suspension for detecting silver ions, which is characterized by being prepared by the preparation method.

The method for detecting silver ions by using the vesicle suspension prepared by the preparation method is characterized in that a sample to be detected is added into the vesicle suspension, and after incubation for 20-25min, the ultraviolet-visible absorption spectrum and the fluorescence emission spectrum of the vesicle suspension are measured: the preferred incubation time is 20min, depending on the time required to achieve maximum colorimetric response in the experiment;

and if the absorption peak at 636-644nm and the absorption peak at 535-545nm in the ultraviolet visible absorption spectrum are obviously reduced, and the fluorescence intensity at 558-562nm and 625-632nm in the fluorescence emission spectrum is obviously increased, determining that the sample to be detected contains silver ions. Different instruments or different operating environments may cause the peak to float within the above-described range.

Further, the sample to be tested is added to the vesicle suspension, and the vesicle suspension changes from blue to red.

Furthermore, when the content of the silver ions in the solution to be detected is within the range of 30-400 mu M, the method can also be used for carrying out quantitative analysis on the silver ions in the solution to be detected.

The invention has the advantages that:

1. compared with the traditional method for detecting silver ions, the polydiacetylene vesicle suspension designed by the invention can be used for Ag in water environment⁺The visual detection of (2) does not need complicated biochemical modification, does not need large-scale instrument and equipment and a fussy sample pretreatment process, has low detection cost, can realize quick real-time analysis, and is simpler, more convenient, quicker and more economic.

2. Disodium ethylene diamine tetraacetate is introduced into the vesicle suspension, and the disodium ethylene diamine tetraacetate in the vesicle suspension is free from Ag under the environment of specific concentration and pH value⁺Other metal ions have strong complexation (the other metal ions are masked), and carboxyl exists at the tail end of the PDA vesicle obtained by self-assembly polymerization of 10, 12-pentacosadiynoic acidCapable of complexing Ag⁺The characteristics of (A) realize the control of Ag⁺Selective detection of (2).

3. The preparation of the vesicle suspension avoids complex chemical synthesis, and can prepare the PDA vesicle suspension without large-scale instruments and equipment, thereby realizing the aim of Ag in a water system⁺Colorimetric and fluorometric dual detection and analysis.

Drawings

FIG. 1 is a scanning electron microscope and a Transmission Electron Microscope (TEM) of the PDA vesicle suspension in example 1 of the present invention, wherein (a) is a SEM (scanning Electron microscope) and (b) is a TEM of different sizes;

FIG. 2 is a DSC curve of pure PCDA and PCDA/EDTA;

FIG. 3 is a FT-IR spectrum of PCDA, EDTA-2Na, and PDA/EDTA;

FIG. 4 shows the UV-Vis spectrum, fluorescence emission spectrum and color change of the PDA vesicle suspension in example 1 before and after response to 16 metal ions (250 μ M); (a) is ultraviolet visible absorption spectrum, (b) is fluorescence emission spectrum, (c) is color change diagram;

FIG. 5 is a schematic diagram of selective recognition of Ag + ions by PDA/EDTA suspensions;

FIG. 6 is the color response of PDA vesicle suspensions to different concentrations of Ag + in example 1 of the present invention;

FIG. 7 shows the UV-VIS absorption spectra of the PDA vesicle suspension of example 1 in response to different concentrations of Ag + and the calibration curves prepared therefrom, wherein (a) shows the UV-VIS absorption spectra, and (b) shows the calibration curves;

FIG. 8 shows the fluorescence emission spectra of the PDA vesicle suspension of the present invention in example 1 after response to different concentrations of Ag +, and the standard curves prepared therefrom, wherein (a) shows the fluorescence emission spectra, and (b) shows the standard curves.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

example 1

(1) Preparation of PDA vesicle suspension:

weighing 7.5mg of 10, 12-pentacosadiynoic acid, dissolving in 10ml of ethanol to prepare an ethanol solution of 10, 12-pentacosadiynoic acid with the concentration of 2mmol/L, and storing for later use; weighing 50mg of disodium ethylene diamine tetraacetate powder, dissolving the disodium ethylene diamine tetraacetate powder in 100mL of HEPES (20mM, pH 7.4) buffer solution under the condition of heating and stirring, preparing into 1.5mmol/L disodium ethylene diamine tetraacetate aqueous solution, and preserving for later use; slowly and dropwise adding 0.5mL of 10, 12-pentacosadiynoic acid ethanol solution into 10mL of ethylene diamine tetraacetic acid aqueous solution at the room temperature of 1000rpm, then placing the obtained colorless suspension in a refrigerator at 4 ℃ for storing in a dark place for 8h, taking out, and irradiating for 5min by using 254nm ultraviolet light (6W, 10cm away from a sample) to obtain blue PDA vesicle suspension; through the scanning electron microscope and transmission electron microscope photographs in fig. 1, it can be confirmed that the PDA vesicle suspension has a spherical vesicle structure.

Meanwhile, the present invention also uses Differential Scanning Calorimetry (DSC) to measure the major phase transition temperature (Tm) of PCDA/EDTA, where Tm represents the transition of lipid chains from a tightly packed phase to a disordered phase. It is known that pure PCDA crystals have a melting point of about 62 ℃ and pure EDTA has a melting point of 248 ℃, and that the addition of EDTA causes a shoulder peak to appear at around 68 ℃ in the endothermic peak of PCDA/EDTA, as shown in FIG. 2. The existence of 68 ℃ shoulder indicates that the introduction of EDTA slightly improves the alignment stability and regularity of PCDA, and also indicates that certain interaction necessarily exists between EDTA and PCDA. The EDTA is mainly present in the form of H in aqueous solutions having a pH of 5 to 9₂Y²And HY³Since protonated carboxyl groups (-COOH) exist in the molecule, theoretically, in the PCDA/EDTA suspension, there is a possibility that hydrogen bonding interaction is formed between EDTA and PCDA molecules, and PCDA and EDTA molecules are connected through hydrogen bonding interaction, which also improves the alignment regularity of the PCDA vesicles.

The interaction between PDA and EDTA present in the suspension can also be demonstrated by FT-IR spectroscopy, as shown in figure 3. Characteristic absorption peak of EDTA-2Na in spectrum is 1640cm-¹And 1400cm-¹. The characteristic absorption peak in the spectrum of PCDA is 1698cm-¹To (3). Whereas the spectrum of the PDA/EDTA after addition of EDTA was at 1647cm-¹New characteristic peaks appear. The protonated carboxyl of EDTA and the carboxyl at the end of PDA form hydrogen bond interaction, which results in the shift of carbonyl absorption peak, and the research result of DSCThis inference is also validated sideways. Meanwhile, the spectrum of the PDA/EDTA still has a characteristic absorption peak of EDTA-2Na, which indicates that part of EDTA-2Na still exists in a free form in the system.

(2) Blue PDA vesicles were used for qualitative and quantitative analysis of Ag +:

respectively preparing Hg in deionized water²⁺、Pb²⁺、Ag⁺、Zn²⁺、Al³⁺、Ca²⁺、Cu²⁺、Co²⁺、Ni²⁺、Mg²⁺、Cr³⁺、Fe³⁺、Sn²⁺、Na⁺、K⁺、Li⁺Sample solutions of sixteen metal ions; respectively adding 2 mu L of the sixteen metal ion sample solutions into 200 mu L of PDA vesicle suspension (the final concentration of metal ions is 250 mu M) at room temperature, incubating for 20min, measuring the ultraviolet visible absorption spectrum and the fluorescence emission spectrum of the PDA vesicle suspension added with different metal ion solutions, observing the specific color response condition by naked eyes, and recording, wherein the specific color response condition is shown in figure 4; according to FIG. 4, Ag⁺The existence of the (B) causes the absorption peak at about 640nm in the ultraviolet-visible spectrum of the PDA to be obviously reduced, the absorption peak at about 540nm to be obviously improved, and the fluorescence intensity at 560nm and 628nm in the fluorescence spectrum to be obviously improved; blue PDA vesicle suspensions were also accompanied by Ag⁺Becomes red, thereby can be added to Ag⁺Qualitative analysis was performed, and the schematic is shown in FIG. 5.

Preparing Ag with different concentrations in deionized water⁺The solution of (1); respectively taking 2 mu L of Ag with a series of concentration gradients at room temperature⁺The solution was added to 200. mu.L of PDA vesicle suspension (Ag)⁺The final concentration of the solution is 0-400 mu M), after incubation for 20min, measuring the ultraviolet visible absorption spectrum and the fluorescence emission spectrum of the PDA vesicle suspension, observing the specific color response condition by naked eyes, and recording (figures 6-8). According to FIG. 6, with Ag⁺The concentration increased, which caused the color response of the PDA vesicle suspension from blue to red to become increasingly apparent. According to FIG. 7, when Ag⁺Ag in the range of 30-400 mu M⁺The higher the concentration, the more it causes the absorption of the PDA vesicle suspension at 640nm in the ultraviolet-visible absorption spectrumThe more the value decreases, the more the absorption at 540nm increases. According to the formulaCalculating different concentrations of Ag⁺CR (colorimetric response) value of PDA after addition, wherein PB is₀Initial ratio before stimulation, PB₁For the final ratio after stimulation, PB (percent blue) is calculated as follows: PB ═ A_blue/(A_blue+A_red) Wherein A is_blueAnd A_redAbsorbance at 640nm and 540nm in the ultraviolet-visible absorption spectrum respectively; with Ag⁺The concentration is plotted on the abscissa and the CR (colorimetric response colorimetric) value is plotted on the ordinate, and the standard curve in FIG. 7 is plotted. According to FIG. 8, when Ag is⁺Ag in the range of 30-400 mu M⁺The higher the concentration, the more it causes an increase in fluorescence intensity at 560nm of the fluorescence spectrum of the PDA vesicle suspension; with Ag⁺The concentration is plotted on the abscissa and the fluorescence intensity at 560nm is plotted on the ordinate, and the standard curve of FIG. 8 is plotted. According to the standard curve in FIG. 7 or FIG. 8, Ag in the concentration range of 30-400. mu.M can be measured⁺Quantitative analysis was performed.

Example 2:

(1) preparation of PDA vesicle suspension:

weighing 7.5mg of 10, 12-pentacosadiynoic acid, dissolving in 10ml of ethanol to prepare an ethanol solution of 10, 12-pentacosadiynoic acid with the concentration of 2mmol/L, and storing for later use; weighing 33.6mg of disodium ethylene diamine tetraacetate powder, dissolving in 100mL of HEPES (20mM, pH 7.4) buffer solution under the condition of heating and stirring, preparing into 1mmol/L disodium ethylene diamine tetraacetate aqueous solution, and storing for later use; under the condition of the rotation speed of 1000rpm at room temperature, 1.0mL of 10, 12-pentacosadiynoic acid ethanol solution is slowly dripped into 10mL of ethylene diamine tetraacetic acid aqueous solution dropwise, the obtained colorless suspension is placed in a refrigerator at 4 ℃ and kept in a dark place for 8h, and the colorless suspension is taken out and irradiated for 10min by 254nm ultraviolet light (6W, 10cm away from a sample) to obtain blue PDA vesicle suspension.

(2) Blue PDA vesicles for Ag⁺Qualitative and quantitative analysis of (2):

the analytical procedure was as in example 1. Of the 16 metal ions to be measured, only Ag⁺The existence of the (B) causes the absorption peak at about 640nm in the ultraviolet-visible spectrum of the PDA to be obviously reduced, the absorption peak at about 540nm to be obviously improved, and the fluorescence intensity at 560nm and 628nm in the fluorescence spectrum to be obviously improved; blue PDA vesicle suspensions were also accompanied by Ag⁺Becomes red, thereby can be added to Ag⁺Qualitative analysis was performed. Determination of addition of different concentrations of Ag⁺UV-VIS absorption spectrum and fluorescence emission spectrum of PDA vesicle suspension in solution, in Ag⁺The concentration is abscissa, the CR value and the fluorescence intensity at 560nm are ordinate respectively, a standard curve is drawn, and Ag is plotted according to the standard curve⁺Quantitative analysis was performed.

Example 3:

(1) preparation of PDA vesicle suspension:

weighing 7.5mg of 10, 12-pentacosadiynoic acid, dissolving in 10ml of ethanol to prepare an ethanol solution of 10, 12-pentacosadiynoic acid with the concentration of 2mmol/L, and storing for later use; weighing 67.2mg of disodium ethylene diamine tetraacetate powder, dissolving the disodium ethylene diamine tetraacetate powder in 100mL of HEPES (20mM, pH 7.4) buffer solution under the condition of heating and stirring, preparing into 2mmol/L disodium ethylene diamine tetraacetate aqueous solution, and storing for later use; under the condition of the rotation speed of 1000rpm at room temperature, 1.5mL of 10, 12-pentacosadiynoic acid ethanol solution is slowly dripped into 10mL of ethylene diamine tetraacetic acid aqueous solution dropwise, the obtained colorless suspension is placed in a refrigerator at 4 ℃ and kept in a dark place for 12 hours, and the colorless suspension is taken out and irradiated for 5 minutes by 254nm ultraviolet light (6W, 10cm away from a sample) to obtain blue PDA vesicle suspension.

(2) Blue PDA vesicles for Ag⁺Qualitative and quantitative analysis of (2):

the analytical procedure was as in example 1. Thus can be applied to Ag⁺Qualitative and quantitative analyses were performed.

Example 4:

(1) preparation of PDA vesicle suspension:

weighing 6.7mg of 10, 12-pentacosadiynoic acid, dissolving in 10ml of ethanol to prepare 1.8mmol/L10, 12-pentacosadiynoic acid ethanol solution, and storing for later use; weighing 67.2mg of disodium ethylene diamine tetraacetate powder, dissolving the disodium ethylene diamine tetraacetate powder in 100mL of HEPES (15mM, pH 7.6) buffer solution under the condition of heating and stirring, preparing into 2mmol/L disodium ethylene diamine tetraacetate aqueous solution, and storing for later use; under the condition of the rotation speed of 1000rpm at room temperature, 1.0mL of 10, 12-pentacosadiynoic acid ethanol solution is slowly dripped into 10mL of ethylene diamine tetraacetic acid aqueous solution dropwise, the obtained colorless suspension is placed in a refrigerator at 4 ℃ and kept in a dark place for 12 hours, and the colorless suspension is taken out and irradiated for 5 minutes by 254nm ultraviolet light (6W, 10cm away from a sample) to obtain blue PDA vesicle suspension.

(2) Blue PDA vesicles for Ag⁺Qualitative and quantitative analysis of (2):

the analytical procedure was as in example 1. Thus can be applied to Ag⁺Qualitative and quantitative analyses were performed.

Example 5:

(1) preparation of PDA vesicle suspension:

weighing 8.2mg of 10, 12-pentacosadiynoic acid, dissolving in 10ml of ethanol to prepare 2.2mmol/L10, 12-pentacosadiynoic acid ethanol solution, and storing for later use; weighing 67.2mg of disodium ethylene diamine tetraacetate powder, dissolving the disodium ethylene diamine tetraacetate powder in 100mL of HEPES (20mM, pH 7.2) buffer solution under the condition of heating and stirring, preparing into 2mmol/L disodium ethylene diamine tetraacetate aqueous solution, and storing for later use; under the condition of the rotation speed of 1000rpm at room temperature, 1.0mL of 10, 12-pentacosadiynoic acid ethanol solution is slowly dripped into 10mL of ethylene diamine tetraacetic acid aqueous solution dropwise, the obtained colorless suspension is placed in a refrigerator at 4 ℃ and kept in a dark place for 12 hours, and the colorless suspension is taken out and irradiated for 10 minutes by 254nm ultraviolet light (6W, 10cm away from a sample) to obtain blue PDA vesicle suspension.

(2) Blue PDA vesicles for Ag⁺Qualitative and quantitative analysis of (2):

the analytical procedure was as in example 1. Thus can be applied to Ag⁺Qualitative and quantitative analyses were performed.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present disclosure.