Organic dye analysis method and system based on Au-coated Ag substrate

Abstract

The invention relates to the technical field of water body pollution detection, in particular to an Au-Ag substrate-based organic dye analysis method and system.When an SERS technology is adopted for water body organic dye detection, an obtained initial SERS spectrum is subjected to data smoothing operation; the relationship between the size of the smoothing coefficient and the concentration of the organic dye and the detection limit of equipment is determined, so that the problem of relatively large artificial influence caused by manually setting the smoothing coefficient is avoided, and the accuracy and the stability of analysis of the low-content organic dye are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution detection, and in particular to an organic dye analysis method and system based on an Au@Ag substrate. Background Art

[0002] Organic dye pollutants in water bodies refer to organic matter produced by human activities, which will affect and change the normal composition and properties of the environment after entering the environment. Organic dye pollutants have the characteristics of long-term residue, bioaccumulation and high toxicity. They are difficult to degrade by physical, chemical or biological means, and pose serious hazards to the ecological environment of water bodies and human health. There are many types of organic dye pollutants in water bodies and their contents in the environment are also different. For example, some organic dye pollutants are highly toxic although their contents are low, and the mixing of multiple organic pollutants and complex environmental conditions will affect the detection. Therefore, this requires the analysis method to have good discrimination ability for different types of environmental pollutants and high sensitivity to certain trace or even trace levels of pollutants.

[0003] There are schemes for detecting organic dyes through SERS substrates in the prior art. For example, a Chinese invention patent (CN117388232A) discloses a method for detecting organic dyes in water based on a self-assembled thermosensitive SERS substrate, comprising the following steps: S1. Add AuNPs@PNIPAM microgel solution, organic dye aqueous solution and metal ion aqueous solution to a sample bottle in sequence, mix them evenly and then perform Raman spectroscopy test; S2. Compare and analyze the Raman spectrum measured by S1 with the Raman characteristic peak database to obtain qualitative and quantitative detection results of organic dyes, and realize self-assembly of AuNPs@PNIPAM microgels by adding metal ions, heating hydrophobic aggregation, high-speed centrifugation, freeze drying, etc., to form a self-assembled thermosensitive SERS substrate to achieve detection. However, in the process of analyzing organic dyes, the above scheme ignores the processing link of SERS spectrum, resulting in low accuracy of organic dye analysis. Summary of the invention

[0004] In view of this, the present invention proposes an organic dye analysis method and system based on Au@Ag substrate, which are used to improve the accuracy and stability of organic dye analysis in water.

[0005] In order to achieve the above object, a method for analyzing organic dyes based on Au@Ag substrate is provided, and the method comprises the following steps:

[0006] S1: Preparation of Au@Ag substrate for organic dye analysis;

[0007] S2: Detect the organic dye wastewater to obtain the SERS spectrum;

[0008] S3: performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum;

[0009] The spectrum smoothing preprocessing operation specifically includes: determining the smoothing coefficient according to the SERS spectrum;

[0010] S4: analyzing the organic dye in the water according to the SERS spectrum after the pretreatment.

[0011] Preferably, the smoothing coefficient λ is determined as follows:

[0012]

[0013] Wherein, a1 is the predicted concentration of the organic dye to be detected, and a2 is the theoretical detection limit of the organic dye to be detected.

[0014] Preferably, the predicted concentration of the organic dye to be detected is obtained by predicting the maximum peak intensity of the SERS curve;

[0015] Wherein, the prediction formula is:

[0016]

[0017] Where y is the predicted concentration of the organic dye, and x is the maximum peak intensity of the SERS spectrum before smoothing. If the maximum peak appears at 1510 cm -1 , the organic dye is considered to be rhodamine, if the maximum peak appears at 1175cm -1 , then the organic dye is considered to be malachite green.

[0018] Preferably, the preparation process of the Au@Ag substrate is:

[0019] S1.1: preparing nano silver ion solution;

[0020] S1.2: preparation of Fe3O4@Au MNPs solution;

[0021] S1.3: Preparation of Au@Ag substrate for organic dye analysis.

[0022] Preferably, S1.1 is specifically as follows: 1 ml of AgNPs is placed in a beaker, and pure water is added accordingly until the volume is fixed to 15 ml to obtain a nano silver ion solution.

[0023] Preferably, S1.2 is specifically as follows: dissolving 100g of dried Fe3O4 microspheres in 50ml of pure water, then adding 50ml of PEI solution to obtain a mixed solution, ultrasonically treating the mixed solution for 30min to form Fe3O4PEI microspheres, and then re-dissolving the Fe3O4PEI microspheres in 10ml of pure water; then adding 100ml of Au seed solution and ultrasonically treating for 30min; then undergoing magnetic separation, washing with pure water for 2-3 times and then resuspending, and adding 200mg PVP and 20mg of reducing agent, ultrasonically reacting for 20min, and then adding 150μL of 1% Haucl4 solution, ultrasonically stirring for 15min to obtain Fe3O4@Au MNPs, and then washing the Fe3O4@Au MNPs with pure water several times, and suspending them in 10ml of pure water to obtain a Fe3O4@Au MNPs solution.

[0024] Preferably, the dried Fe3O4 microspheres are dissolved in pure water by ultrasonic dispersion.

[0025] Preferably, in S2, the SERS spectrum is acquired by collecting using Renishaw inVia and DXR Raman microscopes from Thermo Scientific.

[0026] According to another aspect of the present invention, there is provided an organic dye analysis system based on an Au@Ag substrate, the system adopts the above-mentioned organic dye analysis method based on an Au@Ag substrate, and the system comprises:

[0027] Substrate preparation module, used to prepare Au@Ag substrates for organic dye analysis;

[0028] A SERS spectrum acquisition module is used to detect the organic dye wastewater to be tested and obtain a SERS spectrum;

[0029] A SERS spectrum preprocessing module, used for performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum;

[0030] The analysis module is used to analyze the organic dye in the water body according to the pre-processed SERS spectrum.

[0031] The advantages and beneficial effects of the present invention are:

[0032] When the SERS technology is used to detect organic dyes in water, the present invention performs a data smoothing operation on the obtained initial SERS spectrum, determines the relationship between the size of the smoothing coefficient and the concentration of the organic dye and the detection limit of the equipment, avoids the problem of being greatly affected by artificial influences due to setting the smoothing coefficient, and improves the accuracy and stability of low-content organic dye analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the description of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A flow chart of an organic dye analysis method based on an Au@Ag substrate provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] As attached Figure 1 As shown, an organic dye analysis method based on Au@Ag substrate comprises the following steps:

[0037] S1: Preparation of Au@Ag substrate for organic dye analysis;

[0038] The preparation method of the substrate has a very important influence on the sensitivity and stability of the detection. Since the SERS effect was explored, metallic silver has been the best choice for preparing various active SERS substrates because its resonance is near the visible light and near-infrared wavelength range and this metal has the ability to generate strong electromagnetic fields.

[0039] Wherein, the preparation process of the Au@Ag substrate is:

[0040] S1.1: preparing nano silver ion solution;

[0041] The step S1.1 is as follows: 1 ml of AgNPs is placed in a beaker, and pure water is added accordingly until the volume reaches 15 ml, thereby obtaining a nano silver ion solution;

[0042] S1.2: preparation of Fe3O4@Au MNPs solution;

[0043] Wherein, the S1.2 is specifically as follows: dissolving 100g of dried Fe3O4 microspheres in 50ml of pure water, then adding 50ml of PEI solution to obtain a mixed solution, ultrasonicating the mixed solution for 30min to form Fe3O4PEI microspheres, and then re-dissolving the Fe3O4PEI microspheres in 10ml of pure water; then adding 100ml of Au seed solution and ultrasonicating for 30min, which is beneficial to the adsorption of Au seeds on the surface of Fe3O4PEI microspheres; then undergoing magnetic separation, washing with pure water 2-3 times and then resuspending, and adding 200mg PVP and 20mg of reducing agent, ultrasonically reacting for 20min, and then adding 150μL of 1% Haucl4 solution, ultrasonically stirring for 15min to obtain Fe3O4@Au MNPs, and then washing the Fe3O4@Au MNPs with pure water several times, and suspending them in 10ml of pure water to obtain a Fe3O4@Au MNPs solution;

[0044] The dried Fe3O4 microspheres were dissolved in pure water by ultrasonic dispersion.

[0045] S1.3: Preparation of Au@Ag substrate for organic dye analysis;

[0046] The nanosilver ion solution and the Fe3O4@Au MNPs solution are mixed and slowly stirred for 45 minutes, and then placed in a vacuum drying oven, and after all bubbles are removed, the mixture is evenly coated on a glass slide to form the Au@Ag substrate;

[0047] S2: Detect the organic dye wastewater to obtain the SERS spectrum;

[0048] Take a spoonful of the organic dye wastewater to be tested and drop it on the Au@Ag substrate. After it is dried naturally, perform SERS detection to obtain a SERS spectrum.

[0049] Wherein, the SERS spectra were acquired by Renishaw inVia and DXR Raman microscopes from Thermo Scientific;

[0050] S3: performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum;

[0051] In the process of collecting the SERS spectrum data, background interference will produce certain noise, which will affect the stability of the SERS spectrum. Especially for some low-content organic dye components, if no pretreatment operation is performed, the detection accuracy of the SERS method will inevitably be affected. Therefore, in order to improve the accuracy and stability of the analysis of some low-content organic dyes, it is necessary to perform data pretreatment on the SERS spectrum;

[0052] In this embodiment, the preprocessing is a spectrum smoothing preprocessing operation;

[0053] The spectrum smoothing preprocessing operation is specifically as follows: determining a smoothing coefficient according to the SERS spectrum;

[0054] Among them, in the prior art, the smoothness of the fitting data is generally controlled by adjusting the smoothing coefficient, wherein the influence formula of the smoothing coefficient is:

[0055] y=(I+λD T D) -1 x;

[0056] Among them, y is the smoothed data, x is the data before smoothing, D is the matrix related to the data before smoothing, and λ is the smoothing coefficient;

[0057] In the prior art, the smoothing coefficient is generally set according to the rule that the larger the λ is, the smoother it is, and the smaller the λ is, the closer it is to the data before smoothing. However, the above scheme is highly subjective and is greatly affected by the professional level of data processing personnel. In this embodiment, a method for determining the smoothing coefficient is proposed to solve the problem that the SERS spectra are affected by different background interferences due to the large difference in the content of organic dyes in different water bodies.

[0058] Specifically, the method for determining the smoothing coefficient λ is:

[0059]

[0060] In the formula, a1 is the predicted concentration of the organic dye to be detected, and a2 is the theoretical detection limit of the organic dye to be detected;

[0061] Furthermore, the predicted concentration of the organic dye to be detected is obtained by predicting the maximum peak intensity of the SERS curve;

[0062] Wherein, the prediction formula is:

[0063]

[0064] Where y is the predicted concentration of the organic dye, and x is the maximum peak intensity of the SERS spectrum before smoothing. If the maximum peak appears at 1510 cm -1 If the maximum peak appears at 1175 cm -1 If the organic dye is near , it is considered that the organic dye is malachite green;

[0065] Through the above operation, the relationship between the size of the smoothing coefficient and the concentration of the organic dye and the detection limit of the equipment is determined, avoiding the problem of being greatly affected by human factors when setting the smoothing coefficient, and improving the accuracy and stability of low-content organic dye analysis.

[0066] S4: analyzing the organic dye in the water according to the SERS spectrum after the pretreatment.

[0067] Wherein, the rhodamine and malachite green in the organic dyes are qualitatively analyzed or quantitatively analyzed according to the pretreated SERS spectrum, wherein the qualitative analysis is used to determine whether the water body contains rhodamine or malachite green, and the quantitative analysis is used to determine the content of rhodamine or malachite green in the water body.

[0068] Embodiment 2: This embodiment includes an organic dye analysis system based on an Au@Ag substrate. The system adopts an organic dye analysis method based on an Au@Ag substrate as described in any one of Embodiment 1. The system includes:

[0069] Substrate preparation module, used to prepare Au@Ag substrates for organic dye analysis;

[0070] A SERS spectrum acquisition module is used to detect the organic dye wastewater to be tested and obtain a SERS spectrum;

[0071] A SERS spectrum preprocessing module, used for performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum;

[0072] The analysis module is used to analyze the organic dye in the water body according to the pre-processed SERS spectrum.

[0073] Embodiment 3: This embodiment includes a computer-readable storage medium, on which a data processing program is stored, and the data processing program is executed by a processor to implement an organic dye analysis method based on an Au@Ag substrate in Embodiment 1.

[0074] It will be appreciated by those skilled in the art that the embodiments herein may be provided as methods, devices (equipment), or computer program products. Therefore, this article may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Including but not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store desired information and can be accessed by a computer, etc. In addition, it is well known to those of ordinary skill in the art that communication media generally contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0075] This document is described with reference to flowcharts and / or block diagrams of methods, apparatuses (devices) and computer program products according to the embodiments of this document. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0077] The embodiments and / or implementation methods described above are only used to illustrate the preferred embodiments and / or implementation methods of the technology of the present invention, and are not intended to impose any formal restrictions on the implementation methods of the technology of the present invention. Any person skilled in the art may make some changes or modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as the technology or embodiments that are essentially the same as the present invention. Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and that various obvious changes, readjustments and substitutions can be made to those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An organic dye analysis method based on Au@Ag substrate, characterized in that: The method comprises the following steps: S1: Preparation of Au@Ag substrate for organic dye analysis; S2: Detect the organic dye wastewater to obtain the SERS spectrum; S3: performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum; The spectrum smoothing preprocessing operation specifically includes: determining the smoothing coefficient according to the SERS spectrum; S4: analyzing the organic dye in the water according to the SERS spectrum after the pretreatment.

2. The method for analyzing organic dyes based on Au@Ag substrate according to claim 1, characterized in that: The method for determining the smoothing coefficient λ is: Wherein, a1 is the predicted concentration of the organic dye to be detected, and a2 is the theoretical detection limit of the organic dye to be detected.

3. The method for analyzing organic dyes based on Au@Ag substrate according to claim 2, characterized in that: The predicted concentration of the organic dye to be detected is obtained by predicting the maximum peak intensity of the SERS curve; Wherein, the prediction formula is: Where y is the predicted concentration of the organic dye, and x is the maximum peak intensity of the SERS spectrum before smoothing. If the maximum peak appears at 1510 cm -1 , the organic dye is considered to be rhodamine, if the maximum peak appears at 1175cm -1 , then the organic dye is considered to be malachite green.

4. The method for analyzing organic dyes based on Au@Ag substrate according to claim 1, characterized in that: The preparation process of the Au@Ag substrate is as follows: S1.1: preparing nano silver ion solution; S1.2: preparation of Fe3O4@Au MNPs solution; S1.3: Preparation of Au@Ag substrate for organic dye analysis.

5. The method for analyzing organic dyes based on Au@Ag substrate according to claim 4, characterized in that: The S1.1 is specifically as follows: 1 ml of AgNPs is placed in a beaker, and pure water is added accordingly until the volume is fixed to 15 ml, thereby obtaining a nano silver ion solution.

6. The method for analyzing organic dyes based on Au@Ag substrate according to claim 4, characterized in that: The S1.2 is specifically as follows: 100g of dried Fe3O4 microspheres are dissolved in 50ml of pure water, and then 50ml of PEI solution is added to obtain a mixed solution, the mixed solution is ultrasonicated for 30min to form Fe3O4PEI microspheres, and then the Fe3O4PEI microspheres are redissolved in 10ml of pure water; then 100ml of Au seed solution is added and ultrasonicated for 30min; then magnetic separation is performed, and the mixture is washed with pure water for 2-3 times and then resuspended, and 200mg of PVP and 20mg of reducing agent are added, and ultrasonic reaction is performed for 20min, followed by adding 150μL of 1% Haucl4 solution, and ultrasonic stirring is performed for 15min to obtain Fe3O4@Au MNPs, and then the Fe3O4@Au MNPs are washed with pure water several times and suspended in 10ml of pure water to obtain a Fe3O4@Au MNPs solution.

7. The method for analyzing organic dyes based on Au@Ag substrate according to claim 4, characterized in that: The dried Fe3O4 microspheres were dissolved in pure water by ultrasonic dispersion.

8. The method for analyzing organic dyes based on Au@Ag substrate according to claim 4, characterized in that: In S2, the SERS spectrum is acquired by using Renishaw inVia and DXR Raman microscopes from Thermo Scientific.

9. An organic dye analysis system based on Au@Ag substrate, characterized in that: The system adopts an organic dye analysis method based on an Au@Ag substrate according to any one of claims 1 to 8, and the system comprises: Substrate preparation module, used to prepare Au@Ag substrates for organic dye analysis; A SERS spectrum acquisition module is used to detect the organic dye wastewater to be tested and obtain a SERS spectrum; A SERS spectrum preprocessing module, used for performing data preprocessing operation on the SERS spectrum to obtain a preprocessed SERS spectrum; The analysis module is used to analyze the organic dye in the water body according to the pre-processed SERS spectrum.

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