A Raman Sensing Analysis Method for Hydrogen Sulfide Based on Au-Ag Janus NPs

Abstract

The application is a Raman sensing analysis method for detecting H2S based on Au-Ag Janus NPs, which is sensitive based on surface-enhanced Raman scattering spectrum and can realize nondestructive detection, and takes the Raman peak of the Au-Ag Janus NPs material at 1278 cm ‑1 as the identification position of quantitative analysis, synthesizes Au-Ag Janus NPs by guiding the directional growth of Ag islands on the Au core through the ligand 2-mercaptobenzimidazole-5-carboxylic acid, and the ligand MBIA simultaneously acts as a Raman beacon molecule to enhance the Raman signal, and designs a Raman sensor. The method can detect the concentration content of H2S in the sample through the SERS method, so that the detection is more accurate, has high sensitivity and good stability.

Description

Technical Field

[0001] This invention relates to a Raman sensing analysis method for detecting H2S based on Au-Ag Janus NPs, belonging to the field of Raman spectroscopy analysis technology. Background Technology

[0002] Hydrogen sulfide (H2S) is considered an important signaling molecule, widely present in various tissue types. Endogenous hydrogen sulfide has many specific pathophysiological functions, including regulating vasodilation, anti-inflammation, reducing oxidative stress, and neuromodulation. However, studies have found that abnormal H2S levels are also attributed to the development of several diseases, such as Alzheimer's disease and Down syndrome. It has been reported that excessively high H2S concentrations may promote tumor proliferation and migration. As an electron donor, H2S can stimulate mitochondrial oxidation and phosphorylation, thereby promoting the production of adenosine triphosphate (ATP), which is necessary for tumor cell proliferation and growth.

[0003] Currently, the main methods for detecting H2S include the methylene blue method, fluorescent probe method, gas chromatography-chemiluminescence immunoassay (GC-CMA), and electrochemical analysis. However, these existing methods all have limitations, such as complex operation, high sample preparation and detection costs, the need for expensive instruments, and the requirement for professional personnel to operate them.

[0004] Surface-enhanced Raman scattering (SERS) technology offers advantages such as high detection sensitivity, strong selectivity, and ease of operation. Developing a novel H2S detection method based on SERS could effectively address the aforementioned challenges.

[0005] CN114917971A discloses a microfluidic chip and detection method for trace detection of hydrogen sulfide based on microdroplets. It uses Ag NPs, which requires additional modification of the Raman beacon Cy7. Moreover, Ag NPs have problems such as instability, easy oxidation, weak Raman signal, and low detection sensitivity, which cannot effectively meet the needs of use. Summary of the Invention

[0006] This invention proposes a Raman sensing analysis method for detecting H2S based on Au-Ag Janus NPs, aiming to overcome the above-mentioned shortcomings of existing technologies and improve detection accuracy, sensitivity and stability.

[0007] The technical solution of this invention: A Raman sensing analysis method for detecting H2S based on Au-Ag Janus NPs. This method utilizes surface-enhanced Raman scattering (SERS) spectroscopy, which offers sensitive detection and enables non-destructive testing. The method uses Au-Ag Janus NPs as the Raman substrate at 1278 cm⁻¹. -1Using the Raman peak at a certain point as the identification location for quantitative analysis, Au-Ag Janus NPs were synthesized by guiding the directional growth of Ag islands on the Au core through the ligand 2-mercaptobenzimidazole-5-carboxylic acid (MBIA). The MBIA ligand also acts as a Raman beacon molecule to enhance the Raman signal, thus designing a Raman sensor. This method can detect the concentration of H2S in the sample using SERS, resulting in more accurate detection, high sensitivity, and good stability.

[0008] Specifically, it includes the following steps: (1) Prepare H2S solutions of different concentrations; (2) Mix Au-Ag Janus NPs solution with H2S solution of different concentrations, shake and react for 1 h, and detect the SERS signal intensity of the solution after reaction to achieve qualitative or quantitative analysis of H2S.

[0009] Preferably, in step (1), NaHS is used as the H2S donor to prepare hydrogen sulfide solutions of different concentrations.

[0010] Preferably, the method for preparing the Au-Ag Janus NPs solution in step (2) includes the following steps: S1: Add HAuCl4 solution to ultrapure water, heat to boiling, quickly inject sodium citrate solution, keep the solution boiling for 15 minutes, cool naturally to room temperature, and obtain Au NPs after centrifugation and concentration; S2: Add MBIA ethanol solution to the Au NPs obtained in S1, mix in a water bath at 60°C for 2 hours, cool to room temperature, add HQ solution and AgNO3 solution under vigorous vortex, let stand for 2-3 hours, centrifuge to obtain Au-Ag Janus NPs.

[0011] Preferably, in step S1, the volume ratio of ultrapure water:HAuCl4 solution:sodium citrate solution is 99:1:1, the mass concentration of HAuCl4 solution is 1%-2%, and the mass concentration of sodium citrate solution is 1%-2%.

[0012] Preferably, in step S2, the molar ratio of AgNO3 to HQ is 1.0:5.0-1.0:10.0.

[0013] Preferably, in step (2), the method for preparing the standard curve for quantitative analysis of H2S includes: reacting Au-AgJanus NPs solution with H2S solutions of different concentrations, and then detecting the SERS signal intensity of the mixed solution after the reaction; taking the logarithm of the H2S concentration as the abscissa, and plotting the curve at 1278 cm⁻¹. -1 Using the SERS signal intensity at a given location as the ordinate, a standard curve is obtained.

[0014] Preferably, the concentration range of the H2S solution is 1 nM-100 µM.

[0015] Preferably, 785nm Ar is used. + The SERS signal intensity of the mixed solution after reaction was detected using an ion laser source.

[0016] Advantages of this invention: The H2S Raman sensing analysis method of this invention has high sensitivity and specificity. The MBIA-modified SERS probe Au-Ag Janus NPs are selected, which have a strong and stable SERS signal and strong anti-interference ability. When the target analyte H2S is present, due to the redox reaction between H2S and silver particles in the material, the silver particles in the Au-Ag Janus NPs are oxidized to Ag2S, thereby weakening the SERS intensity and achieving sensitive detection of H2S. The use of a gold-silver heterostructure eliminates the need for additional Raman beacon modification. Compared with existing technologies, silver nanoparticles are more stable, and the signal originates from the plasmon coupling between the two metals, resulting in a stronger signal. Attached Figure Description

[0017] Figure 1 This is a TEM image of Au-Ag Janus NPs prepared according to an embodiment of the present invention.

[0018] Figure 2 This is the SERS diagram of Au-Ag Janus NPs prepared according to an embodiment of the present invention.

[0019] Figure 3 This is the Raman spectrum of the H2S Raman sensor established in an embodiment of the present invention.

[0020] Figure 4 This is a standard curve diagram for detecting H2S established in an embodiment of the present invention.

[0021] Figure 5 This is the stability Raman spectrum of the H2S Raman sensor established in this embodiment of the invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. Example

[0023] (1) Preparation of Au-Ag Janus NPs: Au NPs were synthesized by sodium citrate reduction: 1 mL of 1% HAuCl4 solution was added to 99 mL of ultrapure water and heated to boiling. 1 mL of 1% sodium citrate solution was then rapidly injected into the boiling solution while stirring. The solution was kept boiling for 15 min and then allowed to cool naturally to room temperature. Au NPs were obtained after centrifugation and concentration.

[0024] Take 100 µL of the synthesized Au NPs, dilute to 1 mL with ultrapure water, then add 20 µL of 1 mM MBIA (2-mercaptobenzimidazole-5-carboxylic acid) ethanol solution. Incubate this mixture in a water bath at 60 °C for 2 h, then allow it to cool naturally to room temperature. Under vigorous vortexing, add 80 µL of 10 mM HQ (hydroquinone) solution and 80 µL of 1 mM AgNO3 solution to the above solution, respectively. Let the resulting solution stand for 2-3 h to allow complete reduction of AgNO3, then centrifuge to obtain Au-Ag Janus NPs.

[0025] (2) Establishing a Raman sensor for H2S: Take 45 µl of Au-Ag Janus NPs solution with SERS signal and 5 µl of H2S solution of different concentrations and shake to react for 1 h at room temperature to obtain a mixed solution.

[0026] (3) Establish a standard curve for detecting H2S: Au-Ag Janus NPs were mixed with H2S solutions of different concentrations (0, 1 nM, 10.0 nM, 100.0 nM, 1.0 µM, 10.0 µM, 50.0 µM, 100.0 µM), and reacted with shaking at room temperature for 1 h. The SERS intensity of the mixed solution was detected using a 785 nm Ar+ ion laser source. The logarithm of the H2S concentration was plotted on the x-axis, and the result was plotted at 1278 cm⁻¹. -1 Using the SERS signal intensity at a given location as the ordinate, a standard curve for H2S detection is obtained, enabling qualitative or quantitative analysis of H2S.

[0027] like Figure 5 As shown, the Raman sensor of H2S in this embodiment exhibits good stability under different pH values, ambient temperatures, and storage times.

[0028] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A Raman sensing analysis method for detecting H2S based on Au-Ag Janus NPs, characterized in that, Includes the following steps: (1) Prepare H2S solutions of different concentrations; (2) Mix Au-Ag Janus NPs solution with H2S solution of different concentrations, shake and react for 1 h, and detect the SERS signal intensity of the solution after reaction to achieve qualitative or quantitative analysis of H2S. In step (1), NaHS is used as the H2S donor to prepare hydrogen sulfide solutions of different concentrations. The preparation method of the Au-Ag Janus NPs solution in step (2) includes the following steps: S1: Add HAuCl4 solution to ultrapure water, heat to boiling, quickly inject sodium citrate solution, keep the solution boiling for 15 minutes, cool naturally to room temperature, and obtain Au NPs after centrifugation and concentration; S2: Add MBIA ethanol solution to Au NPs obtained in S1, mix in a water bath at 60°C for 2 hours, cool to room temperature, add HQ solution and AgNO3 solution under vigorous vortex, let stand for 2-3 hours, centrifuge to obtain Au-Ag Janus NPs; In step S1, the volume ratio of ultrapure water: HAuCl4 solution: sodium citrate solution is 99:1:1, the mass concentration of HAuCl4 solution is 1%-2%, and the mass concentration of sodium citrate solution is 1%-2%. In step S2, the molar ratio of AgNO3 to HQ is 1.0:5.0-1.0:10.0; In step (2), the method for preparing the standard curve for quantitative analysis of H2S includes: reacting Au-Ag Janus NPs solution with H2S solutions of different concentrations, and then detecting the SERS signal intensity of the mixed solution after the reaction; taking the logarithm of the H2S concentration as the abscissa, and plotting the curve at 1278 cm⁻¹. -1 Using the SERS signal intensity at a given location as the ordinate, a standard curve is obtained; The concentration range of the H2S solution is 1 nM-100 µM; Using 785nm Ar + The SERS signal intensity of the mixed solution after reaction was detected using an ion laser source.

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