A method for in-situ electrochemical SERS spectral selective screening of molecules

Abstract

The present invention belongs to the technical field of surface Raman enhanced detection, and discloses a method for in-situ electrochemical SERS spectral selective screening of molecules, which prepares a SERS substrate of a gold nanopyramidal dimer array; replaces the capping ligand molecule of PbS quantum dots with 3-mercaptopropionic acid molecules from oleic acid; after cleaning the SERS substrate, drops a PbS quantum dot solution onto the SERS substrate, and obtains a SERS substrate loaded with PbS quantum dots after the methanol solvent volatilizes; uses the SERS substrate and the SERS substrate modified with PbS quantum dots as working electrodes respectively for in-situ electrochemical SERS spectral detection. The present invention utilizes the dielectric effect of PbS quantum dots to enhance the detection sensitivity of the SERS substrate twice, utilizes the in-situ electrochemical potential regulation technology to enhance the SERS substrate three times, and screens and detects different types of trace molecules through simple potential regulation, with high detection sensitivity and accuracy and strong selectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface Raman enhanced detection, and particularly relates to a method for in-situ electrochemical SERS spectroscopy to selectively screen molecules. Background Art

[0002] At present, the discovery of surface-enhanced Raman scattering (SERS) spectroscopy has broken through the sensitivity limit of Raman spectroscopy and opened up a new way for more sensitive molecular detection. Due to the local surface plasmon resonance (LSPR) effect of noble metal nanostructures, the Raman scattering cross-section of molecules adsorbed on noble metal nanostructures can be enhanced by a factor of 10 8 ~10 12 orders of magnitude. Due to its high sensitivity and fingerprint recognition ability for chemical structures and enhancement factors, SERS has been widely used in molecular detection and identification in fields such as chemistry, biology, and medicine. However, due to the fact that different molecules may have the same molecular structure groups, resulting in severe overlapping peaks, SERS technology is often only applicable to the detection of single molecules, and the applicable range is relatively narrow.

[0003] Electrochemical surface-enhanced Raman scattering (EC-SERS) spectroscopy is a technique that uses electrochemical methods and specific electrodes with SERS probe functions to obtain the vibrational information of molecules in electrolyte solutions. In-situ EC-SERS detection is to adjust the properties of the electrode-electrolyte system, including the dielectric constant of the interfacial electrolyte, the coverage and / or adsorption orientation of molecules, and the bonding interaction between molecules and the electrode surface, by changing the potential of the working electrode, that is, the Fermi level. Since the photoelectrochemical reaction can be controlled by regulating the electrode potential, in-situ EC-SERS has more advantages in exploring the physical and chemical processes of complex photoelectrochemical reactions. However, at present, the application of in-situ EC-SERS for selective screening of mixed molecules has limited effects. Therefore, there is an urgent need to design a new method for in-situ electrochemical SERS spectroscopy to selectively screen molecules.

[0004] Through the above analysis, the problems and defects existing in the prior art are as follows:

[0005] (1) Due to the fact that different molecules may have the same molecular structure groups, resulting in severe overlapping peaks, ordinary SERS technology is often only applicable to the detection of single molecules, and the applicable range is relatively narrow.

[0006] (2) At present, the application of in-situ EC-SERS for selective screening of mixed molecules has limited effects. Summary of the Invention

[0007] Aiming at the problems existing in the prior art, the present invention provides a method for in-situ electrochemical SERS spectroscopy to selectively screen molecules.

[0008] The present invention is implemented as follows. A method for in-situ electrochemical SERS spectral selective screening of molecules includes: preparing a SERS substrate with a gold nanopyramid dimer array; replacing the capping ligand molecule of PbS quantum dots from oleic acid with 3-mercaptopropionic acid molecule; after cleaning the SERS substrate, dropping a PbS quantum dot solution onto the SERS substrate, and obtaining a SERS substrate loaded with PbS quantum dots after the methanol solvent evaporates; using the SERS substrate and the SERS substrate modified with PbS quantum dots as working electrodes respectively for in-situ electrochemical SERS spectral detection.

[0009] Further, the method for in-situ electrochemical SERS spectral selective screening of molecules includes the following steps:

[0010] Step 1, preparing a gold nanopyramid dimer array with SERS activity;

[0011] Step 2, preparing a PbS quantum dot solution;

[0012] Step 3, dropping the PbS quantum dot solution onto the cleaned SERS substrate, and obtaining a SERS substrate loaded with a monolayer of PbS quantum dots after the solvent evaporates;

[0013] Step 4, using the SERS substrate loaded with a monolayer of PbS quantum dots as a working electrode, and performing in-situ electrochemical SERS spectral detection by using a Raman spectrometer and an electrochemical workstation.

[0014] Further, the capping ligand molecule of the PbS quantum dot solution in Step 2 is any one of 3-mercaptopropionic acid molecule, S 2- ions or α-S8 elemental sulfur; the first exciton absorption peak of the PbS quantum dots is 540 nm, the concentration is 0.8 μmol / L, and the dispersion solvent is methanol.

[0015] Further, the cleaning method of the SERS substrate in Step 3 is: cleaning the SERS substrate with an ultraviolet ozone cleaning box for 30 min and then immersing it in ultrapure water, and gently drying it with a micro nitrogen stream.

[0016] Further, the dropping amount of the PbS quantum dot solution in Step 3 is 60 μL, the loading amount of the quantum dots is 3.0×10 12 per cm 2 , and the number of loaded layers is within a monolayer.

[0017] Further, the test conditions for the in-situ electrochemical SERS spectral detection in Step 4 are: the electrolyte solution is a solution containing 0.05 mol / L Na2S and 0.1 mol / L NaOH, and the pH of the electrolyte solution is 13.

[0018] Furthermore, the electrolyte solution is pre-purged with high-purity Ar gas for 30 min. The reference electrode is an Ag / AgCl reference electrode, and the counter electrode is a Pt coil.

[0019] Furthermore, the potential used in the in-situ electrochemical measurement is (0) - (-0.4) V.

[0020] Furthermore, the light source is a 785 nm laser; the exposure time is 1 s, and the sampling interval time is 30 s.

[0021] Furthermore, the Raman laser of the Raman spectrometer in step four is matched with the extinction spectrum of the SERS substrate.

[0022] Combined with the above technical solutions and the solved technical problems, the advantages and positive effects of the technical solution to be protected by the present invention are as follows:

[0023] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving these problems, closely combined with the technical solution to be protected by the present invention and the results and data in the R & D process, etc., it is analyzed in detail and profoundly how the technical solution of the present invention solves the technical problems and the creative technical effects brought after solving the problems. The specific description is as follows:

[0024] The present invention provides a method for in-situ electrochemical SERS spectral selective screening of molecules, which is characterized by using the dielectric effect of PbS quantum dots to enhance the detection sensitivity of the SERS substrate twice and using the in-situ electrochemical potential regulation technology to enhance the SERS substrate three times. Compared with the problems that ordinary Raman and conventional SERS can only detect single compounds, different kinds of trace molecules can be screened and detected through simple potential regulation, and fine and accurate molecular vibration spectra can be obtained, with high detection sensitivity, strong selectivity, and high accuracy.

[0025] Compared with the prior art, the present invention has the following advantages compared with the prior art:

[0026] (1) The method for in-situ electrochemical regulation screening and detection of molecules provided by the present invention uses a very small amount of PbS quantum dots to enhance the SERS substrate twice and uses in-situ electrochemical regulation to enhance the SERS substrate three times, making up for the problem of too low spectral signals due to the small number of capping ligand molecules. By combining in-situ electrochemical SERS and PbS quantum dots, the present invention establishes a method for screening and identifying molecules with high sensitivity, strong selectivity, and high accuracy.

[0027] (2) The method for in-situ electrochemically regulated screening and detection of molecules provided by the present invention utilizes the dielectric effect of quantum dots and in-situ electrochemical regulation to enhance the detection sensitivity of the SERS substrate, greatly strengthening the spectral signals of trace photoreaction products and extremely small amounts of capping ligand molecules. Compared with the problem that ordinary Raman and conventional SERS can only detect single compounds, different types of trace molecules can be screened and detected through simple potential regulation, and fine and accurate molecular vibration spectra can be obtained. The method is simple and easy to implement, and the actual detection operation is convenient.

[0028] (3) The present invention provides a method for screening and identifying molecules using in-situ electrochemical SERS spectral technology, which is simple and easy to implement, has a convenient actual detection operation, high sensitivity, strong selectivity, and high accuracy.

[0029] (4) Whether the technical solution of the present invention overcomes the technical prejudice: Since different compounds are prone to produce severely overlapping molecular spectral peaks, SERS and EC-SERS technologies are often only applicable to the detection of single molecules. The present invention uses electrochemical technology to regulate the potential and charge of the electrode, thereby controlling the generation of electron-hole pairs in the gold nanostructure, further regulating the process of the photochemical reaction of the hole sacrificial agent in the solution, and the enhancement of the local electric field generated by the local surface plasmon, and can effectively identify the detection of different trace molecules in the electrochemical electrode system, providing a method and reference basis for the efficient screening of mixture molecules. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a flow chart of the method for in-situ electrochemical SERS spectral selective screening of molecules provided by the embodiments of the present invention;

[0032] Figure 2 It is an extinction spectrum diagram of the PbS quantum dot modified SERS substrate provided by the embodiments of the present invention;

[0033] Figure 3 It is an in-situ electrochemical surface enhanced Raman spectrum diagram from (0) - (-0.4) V provided by Embodiment 1 of the present invention;

[0034] Figure 4A It is an in-situ electrochemical surface enhanced Raman spectrum diagram from (0) - (-0.4) V provided by Embodiment 2 of the present invention;

[0035] Figure 4BIt is the in-situ electrochemical surface-enhanced Raman spectroscopy diagram provided by Embodiment 2 of the present invention in the range of (-0.4)-(0) V;

[0036] Figure 5 It is the Raman spectrum provided by Comparative Example 1 of the present invention and the surface-enhanced Raman spectroscopy diagram of Comparative Example 2. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Aiming at the problems existing in the prior art, the present invention provides a method for in-situ electrochemical SERS spectral selective screening of molecules, which will be described in detail below with reference to the accompanying drawings.

[0039] In order to enable those skilled in the art to fully understand how the present invention is specifically implemented, this part is an explanatory embodiment that expands and explains the technical solutions of the claims.

[0040] As Figure 1 shown, the method for in-situ electrochemical SERS spectral selective screening of molecules provided by the embodiments of the present invention includes the following steps:

[0041] S101, preparing a gold nanopyramidal dimer array with SERS activity;

[0042] S102, preparing a PbS quantum dot solution;

[0043] S103, dropping the PbS quantum dot solution onto the cleaned SERS substrate, and obtaining a SERS substrate loaded with a monolayer of PbS quantum dots after the solvent volatilizes;

[0044] S104, using the SERS substrate loaded with a monolayer of PbS quantum dots as a working electrode, and performing in-situ electrochemical SERS spectral detection by using a Raman spectrometer and an electrochemical workstation.

[0045] The capping ligand molecule of the PbS quantum dot solution in step S102 provided by the embodiment of the present invention is any one of 3-mercaptopropionic acid molecule, S 2- ions or α-S8 elemental sulfur; the first exciton absorption peak of the PbS quantum dots is 540 nm, the concentration is 0.8 μmol / L, and the dispersion solvent is methanol.

[0046] The cleaning method of the SERS substrate in step S103 provided by the embodiment of the present invention is: cleaning the SERS substrate with an ultraviolet ozone cleaning box for 30 min, then immersing it in ultrapure water, and gently drying it with a micro nitrogen stream.

[0047] The Raman laser of the Raman spectrometer in step S104 provided by the embodiments of the present invention matches the extinction spectrum of the SERS substrate.

[0048] As a preferred embodiment, the method for in-situ electrochemical SERS spectral selective screening of molecules provided by the embodiments of the present invention specifically includes the following steps:

[0049] Step 1, prepare an SERS substrate of a gold nanopyramid dimer array.

[0050] Step 2, displace the capping ligand molecule of the PbS quantum dots from oleic acid to 3-mercaptopropionic acid (MPA) molecule. The first exciton absorption peak of the PbS quantum dots is 540 nm, the concentration is 0.8 μmol / L, and the dispersion solvent is methanol.

[0051] Step 3, after cleaning the SERS substrate in step 1, drop 60 μL of the PbS quantum dot solution obtained in step 2 onto the SERS substrate. After the methanol solvent evaporates, an SERS substrate loaded with PbS quantum dots is obtained. The loading amount of the PbS quantum dots is 3.0×10 12 per / cm 2 and the number of loaded layers is within a single layer.

[0052] Step 4, use the SERS substrate obtained in step 1 and the SERS substrate modified with PbS quantum dots obtained in step 3 as working electrodes for in-situ electrochemical SERS spectral detection.

[0053] The test conditions provided by the embodiments of the present invention are as follows: the electrolyte solution used is a solution containing 0.05 mol / L Na2S and 0.1 mol / L NaOH, and the pH of the electrolyte solution is 13; the electrolyte solution is pre-purged with high-purity Ar gas for 30 min; the reference electrode is an Ag / AgCl reference electrode (saturated KCl), and the counter electrode is a Pt coil; the potential used in the in-situ electrochemical measurement is (0)-(-0.4) V (relative to the Ag / AgCl reference electrode); the illumination condition is a laser of 785 nm; the exposure time is 1 s, and the sampling interval time is 30 s.

[0054] The specific principle of the method for in-situ electrochemical SERS spectral selective screening of molecules provided by the embodiments of the present invention is as follows:

[0055] 1) a. Under laser irradiation, the local surface plasmons of the gold nanodimer array generate a local electromagnetic field within the gaps of several nanometers in the triangular pyramid dimer, which can be used as an SERS probe to detect S in the solution 2-Trace sulfur (α-S8) formed by ionic and photoreactions. b. The local surface plasmon relaxation of the gold nanostructure generates electron-hole pairs. At an electrode potential of (0)-(-0.1) V, electrons can be conducted to the circuit through the conductive glass, and holes oxidize S 2- ions to form α-S8, and its vibration mode can be detected by SERS spectroscopy. c. At (-0.2)-(-0.4) V, that is, at a more negative electrode potential, due to the enrichment of electrons on the electrode surface, the electron-hole pairs generated by the local surface plasmon cannot be effectively separated, and S 2- ions are difficult to form a-S8; while S 2- ions adsorb on the surface of the gold nanostructure, can form a stable chemical bond Au-S, and are detected by SERS spectroscopy.

[0056] 2) a. Due to its dielectric property, the PbS semiconductor can further enhance the local electromagnetic field of the gold nanostructure, thereby strengthening the spectral signals of both S 2- ions and α-S8 at a potential of (0)-(-0.2) V. b. At (-0.3)-(-0.4) V, due to the increase in electrons on the electrode surface, the local electric field generated by the local surface plasmon is further enhanced, and the SERS spectral signal of the capping ligand MPA molecule of the PbS quantum dots is detected.

[0057] Some positive effects have been achieved during the research and development or use of the embodiments of the present invention, and it indeed has great advantages compared with the prior art. The following content is described in combination with the data, charts, etc. of the experimental process.

[0058] Example 1

[0059] The preparation method of the SERS substrate provided by the embodiment of the present invention is as follows: On the pretreated ITO conductive glass, an array of gold nanorod dimers is prepared by angle-resolved nanosphere lithography technology and evaporation technology to obtain a SERS substrate with polarization characteristics and local surface plasmon effect under 785 nm laser (see Figure 2 ).

[0060] The in-situ electrochemical SERS spectral measurement conditions provided by the embodiments of the present invention are as follows: The electrolyte solution used is a solution containing 0.05 mol / L Na2S and 0.1 mol / L NaOH, and the pH of the electrolyte solution is 13; The electrolyte solution is pre-purged with high-purity Ar gas for 30 min; The working electrode is a SERS substrate, the reference electrode is an Ag / AgCl reference electrode (saturated KCl), and the counter electrode is a Pt coil; The potential used during in-situ electrochemical measurement is (0) - (-0.4) V (relative to the Ag / AgCl reference electrode); The light illumination condition is a laser at 785 nm; The laser output intensity is 0.53 mW when the polarization direction of the polarizer is 0° and 0.56 mW when the polarization direction is 90°; The exposure time is 1 s, and the sampling interval time is 30 s. The target substances during in-situ electrochemical SERS spectral measurement are sulfides generated in the photoelectrochemical reaction and sulfides adsorbed on the working electrode.

[0061] As Figure 3 shown, at 0 - (-0.2) V, Raman characteristic peaks at 149, 219, 469, and 421 cm -1 are detected on the SERS substrate. These spectral peaks belong to the S-S stretching and bending vibrations of α-S8 (see Table 1). This is because the local surface plasmon relaxation of the gold nanostructure generates electron-hole pairs, and the electrons can be conducted to the circuit through the conductive glass, while the holes oxidize S 2- ions in the solution to form α-S8, and its vibration mode can be detected by the SERS spectrum. At (-0.2) - (-0.4) V, Raman characteristic peaks at 315 and 262 cm -1 are observed. These spectral peaks belong to the Au-S stretching vibration. This is because at negative potentials, electrons are enriched on the electrode surface, and the electron-hole pairs generated by the local surface plasmons cannot be effectively separated, making it difficult for S 2- ions in the solution to form α-S8; while S 2- ions are adsorbed on the surface of the gold nanostructure, forming a stable chemical bond Au-S, which can be detected by the SERS spectrum.

[0062] Table 1 Raman shifts and vibration mode assignments of 3-mercaptopropionic acid (MPA) molecules

[0063]

[0064] Example 2

[0065] The production method of the SERS substrate and the in-situ electrochemical SERS spectral measurement conditions provided in the embodiments of the present invention are the same as those in Example 1. The difference is that the working electrode used in Example 2 is a SERS substrate modified with PbS quantum dots, and the capping ligand molecule of the used PbS quantum dots is 3-mercaptopropionic acid (MPA) molecule. The specific method for modifying the SERS substrate is to drop 20 μL of the PbS quantum dot colloidal solution onto the SERS substrate. After the quantum dot solution is evenly dispersed and the solvent is volatilized, in-situ electrochemical SERS measurement is performed on the obtained Example 2.

[0066] In-situ electrochemical SERS spectral measurement conditions: The electrolyte solution used is a solution containing 0.05 mol / L Na2S and 0.1 mol / L NaOH, and the pH of the electrolyte solution is 13; the electrolyte solution is pre-purged with high-purity Ar gas for 30 min; the working electrode is a SERS substrate, the reference electrode is an Ag / AgCl reference electrode (saturated KCl), and the counter electrode is a Pt coil; the potential used in the in-situ electrochemical measurement is (0)-(-0.4) V and (-0.4)-(0) V (relative to the Ag / AgCl reference electrode); the light illumination condition is a laser of 785 nm; the laser output intensity is 1.26 mW both when the polarizer is at 0° and 90°; the exposure time is 1 s, and the sampling interval time is 30 s. The target substances during the in-situ electrochemical SERS spectral measurement are sulfides generated in the photoelectrochemical reaction, sulfides adsorbed on the working electrode, and the capping ligand MPA molecule of the PbS quantum dots.

[0067] Figure 2 Figure 3 is the extinction spectrum of the SERS substrate modified with PbS quantum dots, indicating that it has a local surface plasmon resonance effect under the irradiation of a 785-nm laser and can be used as an electrochemical SERS working electrode for detection. Figure 4 is the in-situ electrochemical surface-enhanced Raman spectrum obtained with this electrode. As shown in Figure 4, the spectral signals of S 2- ions and α-S8 are both enhanced at the potential of (0)-(-0.2) V. This is because the PbS semiconductor has dielectricity, which can further enhance the local electromagnetic field of the gold nanostructure and obtain a stronger SERS signal. At (-0.3)-(-0.4) V, the stretching vibration of C=O at 1627 cm -1 is observed, the bending vibration of CH2 at 1426 cm -1 the out-of-plane rocking vibration at 1286 cm -1 the twisting vibration at 1191 cm -1 and the C-C at 1055 cm -1 and 1001 cm -1Stretching vibrations, etc. all belong to the SERS spectral signals of the capping ligand MPA molecules of PbS quantum dots. This is because the number of electrons on the electrode surface increases under negative potential, and the local electric field generated by the local surface plasmon is further enhanced, thus detecting trace amounts of the capping ligand MPA molecules. The SERS spectra obtained from (-0.4)-(0)V and (0)-(-0.4)V are basically the same. These phenomena prove that the SERS substrate can be used to screen and detect different low-concentration molecules through electrochemical potential regulation, and the good reproducibility indicates the effectiveness of selective detection.

[0068] Comparative Example 1

[0069] To compare with the in-situ electrochemical SERS spectrum, 20 μL of pure MPA liquid was dropped onto a cleaned glass slide, and its ordinary Raman spectrum was measured in air. The measurement method was as follows: the light source was a 785 nm laser; the laser output intensity was 3.85 mW; the exposure time was 10 s. The Raman spectrum results are as Figure 5 shown. It can be seen from Figure 5 that the signal-to-noise ratio of the MPA molecular spectral peaks measured by ordinary Raman is relatively low.

[0070] Comparative Example 2

[0071] To compare with the in-situ electrochemical SERS spectrum, an SERS substrate modified with MPA molecules was prepared. The specific method was to drop 20 μL of a 10 mmol / L MPA methanol solution (pH = 5) onto the SERS substrate. After standing for 15 min, the surface of the substrate was rinsed with methanol to wash away the excess MPA molecules. After the methanol evaporated, Comparative Example 2 was obtained. The measurement method of the SERS spectrum was as follows: the light source was a 785 nm laser; the laser output intensity was 0.47 mW when the polarization angle of the polarizer was 0° and 0.42 mW when the polarization direction was 90°; the exposure time was 1 s. The SERS spectrum results are as Figure 5 shown. It can be seen from Figure 5 that the signal-to-noise ratio of the SERS spectrum obtained from the gold nanostructure is relatively good, and some characteristic peaks of MPA are enhanced.

[0072] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for in-situ electrochemical SERS spectral selective screening of molecules, characterized in that, The method for in-situ electrochemical SERS spectral selective screening of molecules comprises the following steps: Step 1: Prepare a gold nanopyramidal dimer array with SERS activity; Step 2: Prepare a PbS quantum dot solution; Step 3: Drop the PbS quantum dot solution onto the cleaned SERS substrate. After the solvent evaporates, a SERS substrate loaded with a monolayer of PbS quantum dots is obtained; Step 4: Use the SERS substrate loaded with a monolayer of PbS quantum dots as the working electrode, and perform in-situ electrochemical SERS spectral detection by using a Raman spectrometer and an electrochemical workstation; The capping ligand molecules of the PbS quantum dot solution in step two are any one of 3-mercaptopropionic acid molecules, S 2- ions or α-S8 elemental sulfur; the first exciton absorption peak of the PbS quantum dots is 540 nm, the concentration is 0.8 μmol / L, and the dispersion solvent is methanol; The dropping amount of the PbS quantum dot solution in Step 3 is 60 μL, and the loading amount of the quantum dots is 3.0×10 12 per cm 2 ; The test conditions for the in-situ electrochemical SERS spectral detection in Step 4 are: the electrolyte solution is a solution containing 0.05 mol / L Na2S and 0.1 mol / L NaOH, and the pH of the electrolyte solution is 13; The potential used during in-situ electrochemical determination is (0) - (-0.4) V; The Raman laser of the Raman spectrometer in Step 4 is matched with the extinction spectrum of the SERS substrate.

2. The method for in-situ electrochemical SERS spectral selective screening of molecules according to claim 1, wherein The cleaning method of the SERS substrate in Step 3 is: Clean the SERS substrate with an ultraviolet ozone cleaning box for 30 min, then immerse it in ultrapure water, and gently blow it dry with a micro nitrogen stream.

3. The method for in-situ electrochemical SERS spectral selective screening of molecules according to claim 1, characterized in that, The electrolyte solution is pre-purged with high-purity Ar gas for 30 min. The reference electrode is an Ag / AgCl reference electrode, and the counter electrode is a Pt coil.

4. The method for in-situ electrochemical SERS spectral selective screening of molecules according to claim 1, wherein The illumination condition is a laser of 785 nm; the exposure time is 1 s, and the sampling interval time is 30 s.

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