Application of a DASA compound in copper ion detection, copper ion detection method and test paper

Abstract

The application discloses application of a DASA compound in copper ion detection, a copper ion detection method and test paper, and relates to heavy metal rapid detection technology. The application of the DASA compound in copper ion detection can utilize the DASA molecule with a specific structure to reduce the detection limit of copper ions. Specifically, the DASA molecule utilized in the application has a larger free volume, which is beneficial to isomerization reaction of the triene-enol structure in the DASA molecule to form a cyclic structure; meanwhile, the donor in the DASA molecule can disperse the electron cloud density of the triene-enol structure fragment to reduce the energy barrier of the isomerization reaction of the structure fragment. Therefore, the detection of copper ions by using the DASA molecule can reduce the detection limit of copper ions to below 50nM.

Description

Technical Field

[0001] This invention relates to the field of rapid heavy metal detection technology, specifically to the application of a DASA compound in copper ion detection, a copper ion detection method, and a test strip. Background Technology

[0002] Although copper ions are essential elements for plants and animals, excessively high concentrations can cause the death of bacteria and algae in aquatic environments, and can also damage the liver and kidneys and disrupt gastrointestinal function in humans. Therefore, the identification and detection of copper ions in solutions is of great significance for environmental protection and human health. Currently, commonly used methods for copper ion detection are mainly divided into two categories: direct methods and indirect methods. Direct methods utilize the physical and chemical properties of copper ions themselves, including atomic absorption spectrometry, ion chromatography, and electrochemical detection methods. Indirect methods utilize the specific chemical signal changes generated by the reaction between copper ions and indicators to analyze and detect copper ions, including colorimetric methods developed in recent years. Colorimetric methods have unique advantages, such as ease of operation, fast analysis speed, no need for complex instruments, and the ability to perform on-site analysis. In contrast, direct methods for detecting copper ions require expensive instruments, strict experimental environments, and specialized technicians, making them less suitable for on-site testing and analysis.

[0003] Constructing colorimetric sensors using organic dye molecules is a popular approach among existing methods for copper ion detection. By using organic dye molecules as colorimetric sensors, changes in the dye's absorption spectrum can be used to identify and detect copper ions. However, existing organic dye molecules are complex to synthesize and expensive, and their detection limits are generally in the μM range, meaning they can only detect copper ions at concentrations of 10... -6 Copper ions at concentrations above mol / L were detected.

[0004] The prior art discloses a visible light / Cu 2+ The dual-driven photochromic DASA (donor-acceptor Stenhouse adduct) molecule possesses a trienol junction that can coordinate with copper ions in a copper ion solution, isomerizing from a colored chain structure to a transparent five-membered ring structure, thus making it suitable for use as a copper ion colorimetric sensor. However, the molecule's small free volume leads to easy stacking between molecules, and the isomerization reaction requires overcoming a significant energy barrier, resulting in a detection limit for copper ions as high as 50 nM. Summary of the Invention

[0005] To address the problem that existing copper ion colorimetric sensors do not have sufficiently low detection limits for copper ions, this invention provides an application of a DASA compound in copper ion detection. This DASA molecule can promote the isomerization reaction of trienols through its structure to form a cyclic structure, thereby reducing the detection limit of copper ions to below 50 nM.

[0006] Another object of the present invention is to provide a method for detecting copper ions.

[0007] Another object of the present invention is to provide a copper ion detection test strip.

[0008] Another object of the present invention is to provide a method for preparing copper ion detection test strips.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] An application of a DASA compound in the detection of copper ions, wherein the DASA compound has the structure shown in the following general formula:

[0011]

[0012] In the above DASA compounds, n is 0, 1, 2, 3, and Y is N or CH;

[0013] In the above DASA compounds, R1 is arbitrarily selected from one or more of methyl, ethyl, propyl, or butyl.

[0014] In the above DASA compounds, x1 is 0, 1, 2, 3, 4; y1 is 0, 1, 2, 3, 4.

[0015] The structure of a DASA (donor-acceptor Stenhouse adduct) molecule typically comprises three parts: a donor, an acceptor, and a trienol segment between the donor and acceptor. When the DASA compound used in this invention is applied to the detection of copper ions, the DASA compound can be induced by copper ions to undergo a change in spatial configuration. Specifically, the trienol segment can be induced to undergo an isomerization reaction to form a five-membered ring. At this time, the reaction system changes from colored to transparent, thus enabling the detection of copper ions.

[0016] Existing DASA compounds generally have linear structures, but the DASA compound used in this invention has a non-linear and non-planar structure; specifically, it has a dendritic, multi-branched structure. This structure makes it difficult for the compound molecules to aggregate and stack in the matrix, allowing them to have a larger free volume. Therefore, when the DASA compound is added to the matrix, the DASA compound molecules are more easily induced by other substances in the matrix (specifically copper), leading to changes in spatial configuration (the existence of free volume in the molecule is a prerequisite for changes in spatial configuration). Simultaneously, the donor in the DASA compound used in this invention, specifically the 2,4,6-triphenyl-1,3,5-triazine or 1,3,5-triphenylbenzene structural fragment, can disperse the electron cloud density in the trienol structural fragment, thereby lowering the energy barrier of the trienol isomerization reaction and making it easier for the isomerization reaction to occur. Therefore, using the above-mentioned DASA compound as a copper ion colorimetric sensor in this invention can lower the detection limit of copper ions. By limiting Y to CH or N in the donor of this invention, the core part of the donor can only be a 2,4,6-triphenyl-1,3,5-triazine structure or a 1,3,5-triphenylbenzene structure. If Y is other heteroatoms such as S or O, the resulting donor and acceptor cannot form a structure with a suitable electron cloud density to promote the isomerization reaction of the trienol structure fragment, thereby reducing the detection limit of copper ions.

[0017] It should be noted that in the DASA compound used in this invention, the receptor is... If the acceptor is of a different structure, the energy level difference between the donor and acceptor in the resulting DASA compound will be unsuitable, and the detection limit of copper ions cannot be reduced in the application of copper ion detection.

[0018] In a specific embodiment of the present invention, the above-mentioned DASA compound can be prepared by the following method:

[0019] Aromatic alkylamines and furfural adducts were mixed and dissolved in a mixed solvent of dichloromethane and hexafluoroisopropanol. The mixture was reacted under light-protected conditions and purified to obtain the above-mentioned DASA compound.

[0020] In the above preparation method, aromatic alkylamines can construct the donor fragment in the DASA compound of the present invention; while furanaldehyde adducts, after reacting with aromatic alkylamine compounds, can simultaneously construct the acceptor fragment and the trienol structural fragment in the DASA compound.

[0021] More specifically, the aforementioned aromatic alkylamines can be any of the following:

[0022]

[0023] Where n = 0, 1, 2, 3, and R1 is methyl, ethyl, propyl, or butyl.

[0024] More specifically, the above-mentioned furanaldehyde adduct can be a compound represented by the following formula:

[0025]

[0026] Where x1 is 0, 1, 2, 3, 4; y1 is 0, 1, 2, 3, 4.

[0027] Preferably, the DASA compound contains Cu when detecting copper ions. 2+ The sample to be tested also contained Pb 2+ Zn 2+ Ca 2+ Li + Na + Mg 2+ Fe 2+ Ni 2+ Cd 2+ K + Co 3+ Any one or more of the following.

[0028] In real-world heavy metal pollution systems, multiple heavy metal ions are typically present. When using the aforementioned DASA compound for detection, the trienol segment in the DASA compound structure only undergoes isomerization under the induction of copper ions. Therefore, the DASA compound has a specific detection capability for copper ions. Even when other heavy metal ions are present in the sample, it will not be interfered with by these other heavy metal ions. Thus, this invention allows for the detection of copper ions in samples containing other heavy metal ions, and enables selective detection of specific ions even when multiple heavy metal ions are present in the sample, which better meets the detection needs in real-world applications.

[0029] Preferably, the DASA compound contains Cu when detecting copper ions. 2+ Cu in the sample to be tested 2+ The concentration is ≥3.6×10 -8 mol / L.

[0030] Because the DASA compound used in this invention has a large free volume and is easily induced to undergo isomerization reactions, and the energy barrier for molecular isomerization reactions is lowered, the requirement for the concentration of copper ions in the copper-containing sample is greatly reduced. This allows for the concentration of Cu ions in the sample to be significantly lowered. 2+ The lowest concentration was only 3.6 × 10⁻⁶. -8The detection of copper ions was achieved at a concentration of mol / L (36 nM).

[0031] More preferably, the DASA compound contains Cu when detecting copper ions. 2+ Cu in the sample to be tested 2+ The concentration was 3.6–4.0 × 10⁻⁶. -8 mol / L.

[0032] The lower concentration of copper ions in the sample indicates that the invention has a wider range of applications and can detect trace amounts of copper ions.

[0033] Preferably, n is 1 in the DASA compound.

[0034] When n is 1 in the DASA compound, the donor in the resulting DASA compound is mestriphenyltriazine or triphenylbenzene. The donor is directly connected to the trialenol structural segment, and there is no extra benzene ring. Therefore, the donor has a stronger ability to donate electrons to the trialenol segment.

[0035] Preferably, x1 in the DASA compound is 0, 1, or 2.

[0036] Preferably, y1 in the DASA compound is 0, 1, or 2.

[0037] Preferably, R1 in the DASA compound is a methyl group.

[0038] When x1, y1, and R1 in a DASA compound all follow the above constraints, the resulting DASA compound can balance the relationship between the free volume of the compound and the energy barrier of the trienyl-enol isomerization reaction, thus having a lower detection limit when used to detect copper ions.

[0039] Preferably, Y in the DASA compound is CH.

[0040] Compared to 2,4,6-triphenyl-1,3,5-triazine, the donor with 1,3,5-triphenylbenzene as the core has a lower electron cloud density (triazine contains N with lone pairs of electrons), thus further reducing the energy barrier for isomerization reactions of the trienol structural segment.

[0041] This invention also protects a method for detecting copper ions, comprising the following steps:

[0042] S1. Dissolve the DASA compound in an organic solvent to obtain a DASA compound solution before discoloration. Add Cu to the DASA compound solution before discoloration. 2+ The sample to be tested was used to obtain a DASA compound solution that changed color.

[0043] S2. Different concentrations of Cu2+ The solution was added to the DASA compound solution to obtain different standard solutions. The UV-Vis absorption spectra of each standard solution were measured, and the intensity of the absorption peak at wavelengths of 550–600 nm was plotted on the ordinate. 2+ Plot a standard curve with the concentration of on the x-axis and calculate the linear equation;

[0044] S3. Test the UV-Vis absorption spectrum of the discolored DASA compound solution obtained in step S1, record the intensity of the absorption peak at wavelengths of 550–600 nm, and substitute it into the linear equation obtained in step S2 to obtain the Cu content in the sample. 2+ The concentration.

[0045] When applying the aforementioned DASA compound to detect copper ions, this invention allows for qualitative, quantitative, or semi-quantitative analysis of copper ions directly via colorimetry. After adding the sample to the DASA compound solution, the presence of copper ions can be determined qualitatively by observing whether the solution color changes. For semi-quantitative analysis using colorimetry, the color of the DASA compound solution after the color change is compared visually with that of copper ion standard solutions of different concentrations to determine the presence of copper ions. 2+ Cu in the sample to be tested 2+ The concentration range. To perform quantitative analysis using colorimetry, steps S1 to S3 described above are required to obtain the specific Cu concentration in the sample. 2+ concentration.

[0046] Conventional organic solvents in this field are all applicable to the detection method provided by this invention.

[0047] Preferably, the concentration of DASA compound in the DASA compound solution before color change in step S1 is 0.1–2 × 10⁻⁶. -5 mol / L.

[0048] Within this concentration range, DASA compounds showed more significant detection of copper ions.

[0049] Preferably, the organic solvent in step S1 is acetonitrile.

[0050] In acetonitrile solvent, DASA shows the most significant effect in detecting copper ions.

[0051] The present invention also protects a copper ion detection test strip, the test strip comprising a substrate and a detection substance loaded on the substrate, the detection substance being a DASA compound.

[0052] Conventional substrates in the art, such as filter paper, can be used in the copper ion detection test paper provided by this invention.

[0053] This invention also protects a method for preparing a copper ion detection test strip, comprising the following steps:

[0054] The substrate is immersed in a DASA compound solution for 30–90 seconds. Once the immersion is complete, a copper ion test strip can be obtained.

[0055] The concentration of DASA compound in the DASA compound solution is 0.5–2 mol / L.

[0056] Conventional organic solvents in this field, such as dichloromethane, can be used in the preparation of the above-mentioned DASA compound solutions.

[0057] In a specific embodiment of the present invention, the copper ion detection test strip can be used by: dipping the sample liquid to be tested onto the test strip, observing the color change of the test strip, thereby achieving qualitative analysis of the sample to be tested.

[0058] In a specific embodiment of the present invention, drying is required after impregnation to obtain copper ion test paper.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] This invention utilizes specific DASA compounds to detect copper ions. This fully leverages the free volume of the DASA compound to increase the likelihood of the compound undergoing an isomerization reaction induced by copper ions, and also reduces the electron cloud density of the donor, thereby lowering the energy barrier for the isomerization reaction. Therefore, by using specific DASA compounds to detect copper ions, the detection limit can be reduced to 36 nM, or 3.6 × 10⁻⁶. -8 The concentration is mol / L, and the compound is specific for detecting copper ions. Attached Figure Description

[0061] Figure 1 The graph shows the changes in the absorption spectrum of the DASA compound solution when plotting the standard curve.

[0062] Figure 2 This is a standard curve plotted when copper ions are detected using the detection method provided in Example 1 of this invention.

[0063] Figure 3 This is a schematic diagram showing the color change of the DASA compound solution after the sample to be tested was added in Example 4 of the present invention.

[0064] Figure 4 This is the UV-Vis absorption spectrum of the DASA compound solution after the sample to be tested was added in Example 4 of the present invention.

[0065] Figure 5This is a bar graph showing the absorbance of the DASA compound solution at 550 nm after the sample to be tested was added in Example 4 of the present invention.

[0066] Figure 6 This is a schematic diagram of the color change of the test paper obtained in Example 5 of the present invention. Detailed Implementation

[0067] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0068] Example 1

[0069] This embodiment provides a quantitative detection method for Cu-containing substances. 2+ Cu in the sample to be tested 2+ Methods for determining concentration.

[0070] A method for detecting copper ions includes the following steps:

[0071] S1. Dissolve the DASA compound in acetonitrile to obtain a concentration of 1×10⁻⁶. -5 A mol / L DASA compound solution before discoloration was prepared by adding Cu to the DASA compound solution before discoloration. 2+ The sample to be tested was used to obtain a discolored DASA compound solution; containing Cu 2+ The Cu sample to be tested 2+ The concentration is 4×10 -8 mol / L;

[0072] S2. Equivalent concentrations of 0, 0.2, 0.4, 0.6, and 0.8 (1 equivalent is 1 × 10⁻⁶) -5 Cu (mol / L) 2+ The solution was added to the DASA compound solution before the color change in step S1 to obtain different standard solutions. The UV-Vis absorption spectra of each standard solution were measured, and the intensity of the absorption peak at 576 nm in the spectrum was plotted on the ordinate. 2+ Plot a standard curve with the concentration of on the x-axis and calculate the linear equation;

[0073] S3. Measure the UV-Vis absorption spectrum of the discolored DASA compound solution obtained in step S1. Substitute the intensity change of the absorption peak at 576 nm in the spectrum into the linear equation obtained in step S2 to obtain the Cu content in the sample. 2+ The concentration;

[0074] The DASA compound used in Example 1 above has the following molecular structure:

[0075]

[0076] That is, in the DASA compound, n is 1, Y is CH, x1 is 1, y1 is 1, and R1 is methyl.

[0077] Example 2

[0078] This embodiment provides a quantitative detection method for Cu-containing substances. 2+ Cu in the sample to be tested 2+ Methods for determining concentration.

[0079] A method for detecting copper ions, wherein the difference from Example 1 is:

[0080] Contains Cu 2+ The Cu sample to be tested 2+ The concentration was 3.6 × 10⁻⁶. -8 mol / L.

[0081] Example 3

[0082] This embodiment provides a method for quantitative detection of Cu in a sample. 2+ Methods for determining concentration.

[0083] A method for detecting copper ions, wherein the difference from Example 1 is:

[0084] Contains Cu 2+ The Cu sample to be tested 2+ The concentration is 1×10 -5 mol / L.

[0085] Example 4

[0086] This embodiment provides a method for detecting the concentration of metal ions in a test sample containing different metal ions.

[0087] The samples to be tested are as follows:

[0088] Experimental group:

[0089] Contains only Cu 2+ The sample to be tested;

[0090] Control group:

[0091] Contains only Pb 2+ The sample to be tested;

[0092] Contains only Zn 2+ The sample to be tested;

[0093] Contains only Ca 2+ The sample to be tested;

[0094] Li only + The sample to be tested;

[0095] Contains only Na + The sample to be tested;

[0096] Contains only Mg 2+ The sample to be tested;

[0097] Contains only Fe 2+ The sample to be tested;

[0098] Contains only Ni 2+ The sample to be tested;

[0099] Contains only Cd 2+ The sample to be tested;

[0100] K only + The sample to be tested;

[0101] Contains only Co 3+ The sample to be tested;

[0102] The concentration of metal ions in each sample was 1×10⁻⁶. -4 mol / L.

[0103] The above detection method includes the following steps:

[0104] S1. Dissolve the DASA compound in acetonitrile to obtain a concentration of 1×10⁻⁶. -5 A mol / L DASA compound solution before color change was prepared by adding the sample to be tested to the DASA compound solution before color change, resulting in a DASA compound solution after color change.

[0105] S2. Equivalent concentrations of 0, 0.2, 0.4, 0.6, and 0.8 (1 equivalent is 1 × 10⁻⁶) -5 Cu (mol / L) 2+ The solution was added to the DASA compound solution before the color change in step S1 to obtain different standard solutions. The UV-Vis absorption spectra of each standard solution were measured, and the intensity of the absorption peak at 576 nm in the spectrum was plotted on the ordinate. 2+ Plot a standard curve with the concentration of on the x-axis and calculate the linear equation;

[0106] S3. Test the UV-Vis absorption spectrum of the DASA compound solution after the color change obtained in step S1. Substitute the intensity change of the absorption peak at wavelength 576 nm in the spectrum into the linear equation obtained in step S2 to obtain the concentration of metal ions in the sample to be tested.

[0107] Example 5

[0108] A copper ion detection test strip includes a qualitative filter paper strip and a detection substance loaded on the filter paper strip. The detection substance is a DASA compound with the following molecular structure:

[0109]

[0110] That is, in the DASA compound, n is 1, Y is CH, x1 is 1, y1 is 1, and R1 is methyl.

[0111] The method for preparing the copper ion detection test strip provided in Example 5 above includes the following steps:

[0112] The qualitative filter paper is cut into thin strips of 1cm×2.5cm and immersed in a dichloromethane solution of DASA compound for 60s. After immersion, the copper ion test paper can be obtained.

[0113] The concentration of DASA compound in the DASA compound solution is 1 mol / L.

[0114] The above copper ion test strips are used as follows:

[0115] Dip the sample solution into the test paper, drop it onto the test paper, and observe the color change of the test paper to achieve qualitative analysis of the sample. The sample to be tested is as follows:

[0116] Experimental group:

[0117] Contains only Cu 2+ The sample to be tested;

[0118] Control group:

[0119] Contains only Pb 2+ The sample to be tested;

[0120] Contains only Zn 2+ The sample to be tested;

[0121] Contains only Ca 2+ The sample to be tested;

[0122] Li only + The sample to be tested;

[0123] Contains only Na + The sample to be tested;

[0124] Contains only Mg 2+ The sample to be tested;

[0125] Contains only Fe 2+ The sample to be tested;

[0126] Contains only Ni 2+ The sample to be tested;

[0127] Contains only Cd 2+ The sample to be tested;

[0128] K only+ The sample to be tested;

[0129] Contains only Co 3+ The sample to be tested;

[0130] The concentration of metal ions in each sample was 1×10⁻⁶. -4 mol / L.

[0131] Comparative Example 1

[0132] A method for detecting copper ions, wherein the difference from Example 1 is:

[0133] S1. Dissolve the DASA compound shown in the following formula in acetonitrile to obtain a DASA compound solution;

[0134]

[0135] S2. Plot a standard curve with the intensity of the absorption peak at a wavelength of 524 nm in the spectrum as the ordinate and calculate the linear equation;

[0136] S3. The Cu content in the sample was calculated by measuring the intensity of the absorption peak at 524 nm in the spectrum. 2+ The concentration.

[0137] Comparative Example 2

[0138] A method for detecting copper ions, wherein the difference from Example 1 is:

[0139] S1. Dissolve the DASA compound shown in the following formula in acetonitrile to obtain a DASA compound solution;

[0140]

[0141] S2. Plot a standard curve with the intensity of the absorption peak at a wavelength of 601 nm in the spectrum as the ordinate and calculate the linear equation;

[0142] S3. The Cu content in the sample was calculated by measuring the intensity of the absorption peak at 601 nm in the spectrum. 2+ The concentration.

[0143] Performance testing

[0144] Detection limit calculation: Based on the standard curve and the detection limit calculation formula. The detection limit is calculated, where K is a constant related to the confidence concentration, and 3 is taken as the standard for calculating the detection limit; δ is the blank standard deviation, reflecting the stability of the instrument signal; S is the slope of the analytical calibration curve in the low concentration range; and L is the calculated value of the detection limit.

[0145] Specific performance test data are shown in Tables 1-2 below. Figures 1-6As shown:

[0146] Table 1. Test Results of the Experimental Cases

[0147]

[0148] Table 2. Detection Limit Data for Examples and Comparative Examples

[0149] Example 1 36 Comparative Example 1 50 Comparative Example 2 238

[0150] As can be seen from the results in Tables 1-2 above, the method provided in Examples 1-3 of this invention is effective for copper ion concentrations of 40 nM (4 × 10⁻⁶). -8 When detecting samples containing 36 nM, 36 nM, and 1000 nM, accurate results were obtained, demonstrating that the detection method provided by this invention has excellent accuracy in the detection of copper ions. However, when using the method provided in Comparative Examples 1 and 2 to detect samples containing 40 nM copper ions, copper ions could not be detected, indicating that the detection limits of the DASA compounds used in Comparative Examples 1 and 2 for copper ions were all above 40 nM. Furthermore, according to the data from Comparative Example 2, when the acceptor fragment in the DASA compound is not... Instead When the energy level difference between the donor and acceptor of the DASA compound is not suitable, the energy barrier increases when the trienol structural fragment undergoes isomerization. Therefore, when the compound in Comparative Example 2 is used to detect copper ions, more copper ions are needed to induce the trienol isomerization to form a transparent five-membered ring structure. This results in a significant increase in the detection limit of copper ions when the detection method of Comparative Example 2 is used to detect copper ions.

[0151] Figure 1 This graph shows the changes in the absorption spectrum of the DASA compound solution when plotting a standard curve. Figure 1 As can be seen, when using DASA compounds to detect copper ions, the absorption peak of the compound itself weakens as the concentration of copper ions increases. This proves that DASA compounds can indeed react with copper ions, and therefore can be used to detect copper ions.

[0152] Figure 2 This is a standard curve plotted when detecting copper ions using the detection method provided in Example 1 of this invention. According to... Figure 2 Based on the corresponding calculation formula, the detection limit for copper ions using DASA compounds can be calculated to be 36.525508 nM.

[0153] Figure 3 This is a schematic diagram illustrating the color change of the DASA compound solution after the sample to be tested was added in Example 4 of the present invention. Figure 4This is the UV-Vis absorption spectrum of the DASA compound solution after adding the test sample in Example 4 of this invention. Figure 5 This is a bar graph showing the absorbance of the DASA compound solution at 550 nm after the sample to be tested was added in Example 4 of this invention. From... Figures 3-5 It can be seen that the DASA compound used in this invention has a specific response effect only to copper ions. Therefore, when using the DASA compound to detect whether a sample contains copper ions, even if the sample contains other metal ions, it will not interfere with the detection results.

[0154] Figure 6 This is a schematic diagram illustrating the color change of the test strip obtained in Example 5 of the present invention. From... Figure 6 As can be seen from this, a drop containing only Cu was dipped in. 2+ The test strip for the sample under test shows the most obvious color change, fading from purple to colorless. Therefore, the copper ion test strip provided by this invention has a specific response capability to copper ions.

[0155] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An application of a DASA compound in the detection of copper ions, characterized in that, The DASA compound has the structure shown in the following general formula: ； In the DASA compound, n is 0, 1, 2, 3, and Y is N or CH; In the DASA compound, R1 is arbitrarily selected from one or more of methyl, ethyl, propyl, or butyl. In the DASA compound, x1 is 0, 1, 2, 3, 4; y1 is 0, 1, 2, 3, 4.

2. The application as described in claim 1, characterized in that, The DASA compound contains Cu when detecting copper ions. 2+ The sample to be tested also contained Pb 2+ Zn 2+ Ca 2+ Li + Na + Mg 2+ Fe 2+ Ni 2+ Cd 2+ K + Co 3+ Any one or more of the following.

3. The application as described in claim 1, characterized in that, The DASA compound contains Cu when detecting copper ions. 2+ Cu in the sample to be tested 2+ The concentration is ≥3.6×10 -8 mol / L.

4. The application as described in claim 3, characterized in that, The DASA compound contains Cu when detecting copper ions. 2+ Cu in the sample to be tested 2+ The concentration was 3.6~4.0×10. -8 mol / L.

5. A method for detecting copper ions, characterized in that, Includes the following steps: S1. Dissolve the DASA compound in an organic solvent to obtain a DASA compound solution before discoloration. Add Cu to the DASA compound solution before discoloration. 2+ The sample to be tested was used to obtain a DASA compound solution that changed color. S2. Different concentrations of Cu 2+ The solution was added to the DASA compound solution to obtain different standard solutions. The UV-Vis absorption spectra of each standard solution were measured, and the intensity of the absorption peak at wavelengths of 550-600 nm was plotted on the ordinate. 2+ Plot a standard curve with the concentration of on the x-axis and calculate the linear equation; S3. Test the UV-Vis absorption spectrum of the discolored DASA compound solution obtained in step S1, record the intensity of the absorption peak at wavelengths of 550-600 nm, and substitute it into the linear equation obtained in step S2 to obtain the Cu content in the sample. 2+ The concentration; The DASA compound has the structure shown in the following general formula: ； In the DASA compound, n is 0, 1, 2, 3, and Y is N or CH; In the DASA compound, R1 is arbitrarily selected from one or more of methyl, ethyl, propyl, or butyl. In the DASA compound, x1 is 0, 1, 2, 3, 4; y1 is 0, 1, 2, 3, 4.

6. The copper ion detection method as described in claim 5, characterized in that, In step S1, the concentration of DASA compound in the DASA compound solution before discoloration is 0.1~2×10⁻⁶. -5 mol / L.

7. The copper ion detection method as described in claim 5, characterized in that, The organic solvent in step S1 is acetonitrile.

8. A copper ion detection test strip, characterized in that, The test strip includes a substrate and a detection substance loaded on the substrate, wherein the detection substance is a DASA compound. The DASA compound has the structure shown in the following general formula: ； In the DASA compound, n is 0, 1, 2, 3, and Y is N or CH; In the DASA compound, R1 is arbitrarily selected from one or more of methyl, ethyl, propyl, or butyl. In the DASA compound, x1 is 0, 1, 2, 3, 4; y1 is 0, 1, 2, 3, 4.

9. A method for preparing the copper ion detection test strip according to claim 8, characterized in that, Includes the following steps: The substrate is immersed in a DASA compound solution for 30-90 seconds. After immersion, a copper ion test strip can be obtained. The concentration of DASA compound in the DASA compound solution is 0.5~2 mol / L.

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