SERS (Surface Enhanced Raman Scattering) nanoprobe for hydrogen sulfide detection and preparation method thereof

Abstract

The invention discloses an SERS (Surface Enhanced Raman Scattering) nanoprobe for hydrogen sulfide detection and a preparation method thereof in the technical field of SERS detection, and the SERS nanoprobe for hydrogen sulfide detection is of a core-shell-satellite structure consisting of gold nanoparticles and a metal organic framework (MOF) structure, which is called Au (at) ZIF-8 (at) Au for short. The core is a large-size gold nanosphere, the shell layer is a zeolite imidazole acid frame structure ZIF-8, and a small-size gold nanosphere is adsorbed outside the shell layer. The SERS nano-probe for hydrogen sulfide detection provided by the invention is of a special core-shell satellite structure, has abundant nano-gaps, forms more hot spots, can enhance Raman signals of reporter molecules in the gaps, and has higher sensitivity.

Description

Technical Field

[0001] The invention relates to the technical field of SERS detection, and in particular to a SERS nanoprobe for hydrogen sulfide detection and a preparation method thereof. Background Art

[0002] Hydrogen sulfide (H 2 S) is a new type of endogenous gaseous transmitter molecule after nitric oxide (NO) and carbon monoxide (CO) in the body. 2 The physiological concentration of S is related to many physiological processes, including the regulation of the cardiovascular system, the stability of the nervous and immune systems, the proliferation and apoptosis of human cells, on the other hand, H 2 Abnormal S levels are also closely related to a series of malignant diseases, such as Alzheimer's disease, Down syndrome, diabetes, acute kidney injury, etc. 2 The physiological and pathological roles of S in health and disease, and the development of sensitive and accurate in vivo H 2 In the past, a variety of methods have been developed to detect H 2 There are many methods for detecting S, such as gas chromatography, electrochemical method, fluorescence imaging, colorimetry and UV-visible spectrophotometry. However, most of these methods require complex sample pretreatment, and some methods have low detection sensitivity and poor specificity. Surface enhanced Raman scattering (SERS) technology has been used in many biomedical related fields such as bioimaging, drug tracing, tumor diagnosis, etc., with its unique fingerprint characteristics, high sensitivity, no autofluorescence, and no influence of photobleaching, and has shown great advantages.

[0003] The enhancement mechanism of SERS technology is dominated by electromagnetic field enhancement, and the enhancement effect mainly comes from the electromagnetic field enhancement on the metal nanostructure, the so-called "hot spot". Therefore, efforts to construct nanoprobes with strong electromagnetic hot spots and place more analytes in the hot spot area can greatly enhance their Raman signals and achieve ultra-high sensitivity detection of the analytes. Existing methods for increasing SERS hot spots include designing and manufacturing metal nanostructures of specific shapes and sizes, such as nanorods, nanostars, nanobipyramids, etc.; constructing core-shell structures or core-satellite structures to produce nanogaps to increase the number of hot spots. In addition, substances that specifically bind to the analytes are modified at the hot spots to attract more analytes to be in the hot spots.

[0004] H in living cells 2 S is highly volatile and rapidly decomposes, resulting in extremely low content, which makes detection sensitivity difficult. In addition, the composition of substances in living cells is complex. For example, some biomacromolecules such as proteins containing thiol groups will be indiscriminately adsorbed on metal substrates, which will affect H 2 Therefore, the specific detection of H2 The enrichment of S and the screening of macromolecules are necessary conditions. The metal organic framework (MOF) structure is a type of porous crystalline material formed by connecting a metal center with various organic groups. It has the characteristics of high porosity and large specific surface area, and has excellent capabilities in gas separation and storage. Therefore, the introduction of MOF structure on the surface of the metal substrate can greatly enhance the contact between the gas and the SERS substrate and improve the detection sensitivity. At the same time, the MOF structure can also be used as a molecular sieve to block the interference of other macromolecules. Zeolite imidazolate frame (ZIF-8) is an extremely attractive porous material, mainly due to its unique pore structure and stability. It has good biocompatibility in living cells, so ZIF-8 can be used as H 2 An effective enrichment medium for S. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a SERS nanoprobe for hydrogen sulfide detection and a preparation method thereof. The SERS nanoprobe for hydrogen sulfide detection is a special core-shell satellite structure with abundant nanogaps to form more "hot spots", which can enhance the Raman signal of the reporter molecule located in the gap, thereby improving the detection sensitivity.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a SERS nanoprobe for hydrogen sulfide detection, wherein the composite structure of the SERS nanoprobe for hydrogen sulfide detection is represented by Au@ZIF-8@Au;

[0008] The SERS nanoprobe for hydrogen sulfide detection is a core-shell-satellite structure, wherein the core is a first gold nanosphere, the shell is a zeolite imidazole framework ZIF-8, and the outer portion of the shell is adsorbed with a second gold nanosphere;

[0009] The first gold nanosphere is modified with dithiodiphenylazide DTPA, the surface ligand of the first gold nanosphere is hexadecyltrimethylammonium bromide CTAB, and the surface ligand of the second gold nanosphere is sodium citrate.

[0010] Furthermore, the diameter of the first gold nanosphere is 70-80 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 540-545 nm;

[0011] And / or, the overall diameter of the ZIF-8 coated first gold nanosphere is 80-110 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 550-560 nm;

[0012] And / or, the diameter of the second gold nanosphere is 15-20 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 518-521 nm;

[0013] And / or, the diameter of the SERS nanoprobe for hydrogen sulfide detection is 90-130 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 650-660 nm.

[0014] In a second aspect, the present invention provides a method for preparing the SERS nanoprobe for hydrogen sulfide detection, comprising:

[0015] preparing a first gold nanosphere solution of CTAB ligand;

[0016] A layer of ZIF-8 is coated on the first gold nanospheres of CTAB ligand to obtain Au@ZIF-8 solution;

[0017] DTPA was modified on the surface of Au@ZIF-8 to obtain a DTPA-modified Au@ZIF-8 solution;

[0018] The second gold nanospheres with sodium citrate ligands were adsorbed on the surface of Au@ZIF-8 modified with DTPA to obtain a SERS nanoprobe solution for hydrogen sulfide detection.

[0019] Furthermore, the preparation of the first gold nanosphere solution of CTAB ligands comprises:

[0020] At 23-26℃, HAuCl 4 The solution was mixed evenly with the CTAB solution, and pre-chilled NaBH 4 The solution was stirred at a speed of 500-550 rpm for 2-4 hours to obtain a seed solution, wherein the HAuCl 4 , CTAB and NaBH 4 The volume ratio is (1-2):(30-60):(2.4-4.8);

[0021] At 23-26°C, add CTAB solution, HAuCl 4 solution and ascorbic acid solution, and stirring uniformly to obtain a growth solution, wherein the ionized water, CTAB solution, HAuCl 4 The volume ratio of the solution and the ascorbic acid solution is (1-2): (0.05-0.1): (0.02-0.04): (0.07-0.14);

[0022] Add the seed solution to the growth solution, invert for 5-15 seconds, place in 30-40°C warm water and let stand for 10-12 hours, separate the precipitate A by centrifugation, and disperse the precipitate A in deionized water to prepare a gold nanosphere solution, wherein the volume ratio of the seed solution to the growth solution is (1-2): (110-220), and the mass ratio of the precipitate A to deionized water is 1: (2-4);

[0023] In a 40-50℃ water bath, CTAC, ascorbic acid, HAuCl 4 The gold nanosphere solution is added to the mixed solution, stirred for 2-4 hours, and the precipitate B is separated by centrifugation. The precipitate B is redissolved in the CTAB solution to obtain a gold nanopolyhedron solution, wherein the CTAC, ascorbic acid, HAuCl 4 The volume ratio of the mixed solution to the gold nanosphere solution is 1: (1.5-3) × 10 -3 , the mass ratio of the precipitate B to the CTAB solution is 1:(30-60);

[0024] HAuCl 4 The solution is added to the gold nanopolyhedron solution, stirred for 1-3 hours under a 40-50°C water bath condition, and the precipitate C is separated by centrifugation, and the precipitate C is redissolved in deionized water to obtain the first gold nanosphere solution of CTAB ligand, wherein the HAuCl 4 The volume ratio of the solution to the gold nanopolyhedron solution is (1-2): (150-300), and the mass ratio of the precipitate C to deionized water is 1: (10-20).

[0025] Furthermore, the first gold nanospheres of the CTAB ligands are coated with a layer of ZIF-8 to obtain an Au@ZIF-8 solution, comprising:

[0026] The first gold nanosphere solution of the CTAB ligand is added to the 2-methylimidazole solution, stirred evenly, and then a soluble zinc salt solution is added, stirred evenly and allowed to stand, and a precipitate D is separated by centrifugation. The precipitate D is washed with methanol and dissolved in a methanol solution to obtain an Au@ZIF-8 solution.

[0027] Furthermore, the preparation conditions of coating a layer of ZIF-8 on the first gold nanosphere of CTAB ligand to obtain Au@ZIF-8 solution are 23-26°C;

[0028] The volume ratio of the 2-methylimidazole solution, the first gold nanosphere AuNPs solution and the soluble zinc salt solution is (1-3): (1~2): (1-3);

[0029] The step of stirring evenly and then leaving the mixture to stand comprises leaving the mixture to stand for 10-30 minutes.

[0030] Further, DTPA is modified on the surface of Au@ZIF-8 to obtain Au@ZIF-8 modified with DTPA, including: adding DTPA solution to Au@ZIF-8 solution, stirring at constant temperature for 3-5 hours, centrifuging to separate precipitate E, and redissolving the precipitate E in methanol solution to obtain DTPA-modified Au@ZIF-8 solution;

[0031] The volume ratio of the DTPA solution to the Au@ZIF-8 solution is (1-2)×10 -2 :1.

[0032] Furthermore, the second gold nanospheres with sodium citrate ligands are adsorbed on the surface of Au@ZIF-8 modified with DTPA to obtain a SERS nanoprobe for hydrogen sulfide detection, comprising:

[0033] Add HAuCl in deionized water 4 The solution is heated to boiling, and then sodium citrate solution is added, stirred until the solution changes to wine red, and cooled to obtain a second gold nanosphere solution containing sodium citrate ligands;

[0034] The second gold nanosphere solution of the sodium citrate ligand is added to the DTPA-modified Au@ZIF-8 solution, stirred at 23-26° C., centrifuged to remove excess unadsorbed second gold nanospheres, and the precipitate F is taken out and redissolved in methanol to obtain a SERS nanoprobe solution for hydrogen sulfide detection.

[0035] Furthermore, the deionized water, HAuCl 4 The volume ratio of solution and sodium citrate solution is (50-100): (5-10)×10 -2 : (4-8);

[0036] The volume ratio of the second gold nanosphere solution of the sodium citrate ligand to the Au@ZIF-8 solution modified by DTPA is (0.2-0.3): (1-1.5).

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The SERS nanoprobe for hydrogen sulfide detection provided by the present invention is coated with a ZIF-8 shell layer on a large-sized gold nanosphere. On the one hand, the ZIF-8 shell layer can enrich hydrogen sulfide on the surface of the gold nanosphere core. On the other hand, ZIF-8, as a porous material, can hinder the adsorption of macromolecules at hot spots, reduce interference with hydrogen sulfide detection, and thus improve the sensitivity of detection. Small-sized gold nanospheres are adsorbed on the outside of the ZIF-8 shell layer, so that the SERS nanoprobe for hydrogen sulfide detection is a special core-shell satellite structure with abundant nanogaps, forming more "hot spots", and can enhance the Raman signal of the reporter molecule located in the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the synthesis and detection principle of a SERS nanoprobe for hydrogen sulfide detection provided by an embodiment of the present invention;

[0040] Figure 2 is an ultraviolet-visible light absorption spectrum of a SERS nanoprobe for hydrogen sulfide detection provided by an embodiment of the present invention;

[0041] Figure 3 This is a SERS spectrum diagram of the reaction between the SERS nanoprobe for hydrogen sulfide detection provided by an embodiment of the present invention and hydrogen sulfide. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0043] In the following examples, the preparation method of the DTPA solution is as follows: the purchased DTPA powder is weighed and prepared into a 1 mM DTPA solution with anhydrous ethanol, and the DTPA solution is stored in a brown bottle and kept at a low temperature in a dark place for future use.

[0044] Example

[0045] This embodiment provides a SERS nanoprobe for hydrogen sulfide detection and a preparation method thereof. The composite structure of the SERS nanoprobe for hydrogen sulfide detection is represented by Au@ZIF-8@Au. The SERS nanoprobe for hydrogen sulfide detection is a core-shell-satellite structure, wherein the core is a large-sized gold nanosphere, the shell is a zeolite imidazole acid framework ZIF-8, and small-sized gold nanospheres are adsorbed on the outside of the shell;

[0046] The large-sized gold nanospheres are modified with dithiodiphenylazide DTPA, the surface ligands of the small-sized gold nanospheres are hexadecyltrimethylammonium bromide CTAB, and the surface ligands of the small-sized gold nanospheres are sodium citrate.

[0047] like Figure 1 As shown, the preparation method of the SERS nanoprobe for hydrogen sulfide detection provided in this embodiment includes:

[0048] When preparing the SERS nanoprobe for hydrogen sulfide detection in the present invention, the preparation method of the large-sized gold nanosphere core probe used can be selected as follows:

[0049] (1) Preparation of seed solution: At room temperature (25°C), add 0.25 ml of 10 mM HAuCl 4 The solution was mixed evenly with 7.5 ml of 0.1 M CTAB solution, and 0.6 ml of pre-chilled 10 mM NaBH 4 The solution was gently stirred at 500-550 rpm for 3 h to obtain a dark brown seed solution;

[0050] The seed solution needs to be stored at 25°C and used within 2 hours.

[0051] (2) Preparation of ~20 nm gold nanosphere solution: At room temperature (25°C), add 2 ml of 0.1 M CTAB solution, 0.8 ml of 10 mM HAuCl 4 solution and 3 ml of 0.1 M ascorbic acid solution, stirred until uniform to obtain a growth solution; then, the seed solution was added to the growth solution, gently inverted for 10 seconds, placed in 35°C warm water and allowed to stand overnight, centrifuged at 9000-12000 rpm for 10-30 minutes to remove the supernatant, and the precipitate was redispersed in 2 ml of deionized water to obtain ~20 nm gold nanospheres.

[0052] (3) Preparation of large-sized gold nanospheres: Under 45°C water bath conditions, 30 ml of 25 mM CTAC solution, 0.75 ml of 0.1 M ascorbic acid solution, and 1.5 ml of 10 mM HAuCl 4 50 μl of ~20 nm gold nanospheres were added to the mixed solution, and the mixture was gently stirred at 450-550 rpm for 3 h. After centrifugation, the precipitate was redissolved in 30 ml of 0.02 M CTAB solution to prepare a gold nanopolyhedron solution. 0.2 ml of 10 mM HAuCl 4 The solution was added to the gold nanopolyhedron solution, gently stirred at 450-550 rpm for 2 h in a 45°C water bath, centrifuged at 6000-8000 rpm for 10 min and redissolved in 10 ml of deionized water to obtain brick-red large-sized gold nanospheres with a particle size of about 72 nm.

[0053] Generally, in order to remove the excess surfactant CTAB and other unreacted reagents in the above-mentioned gold nanorod solution, the prepared gold nanosphere solution needs to be centrifuged at a speed of 6000-8000 rpm for 10-30 minutes, the supernatant is removed, and the obtained precipitate is redispersed in deionized water, and the operation is repeated twice.

[0054] When preparing the SERS nanoprobe for hydrogen sulfide detection in the present invention, the preparation method of the Au@ZIF-8 used can be:

[0055] After diluting the large-size gold nanosphere solution prepared above by 4 times, 3 ml was added to 3 ml of 0.924 M 2-methylimidazole solution and mixed, and stirred at 550 rpm for 5 min. Subsequently, a 16.8 mM zinc nitrate hexahydrate solution with the same volume as the 2-methylimidazole solution was added to the above mixture, stirred at room temperature (25°C) for 5 min, and allowed to stand for 15 min; the excess precursor solution was removed by centrifugation at 3500 rpm for 5 min, and the precipitate was redissolved in 3 ml of methanol solution. The operation was repeated twice to obtain the Au@ZIF-8 nanoprobe.

[0056] Add 10 μl of 1 mM DTPA solution to the above 1 ml Au@ZIF-8 solution, incubate overnight at room temperature (25°C) on a shaker at 400 rpm, centrifuge to remove the supernatant, and redissolve the precipitate in 1 ml of methanol;

[0057] When preparing the SERS nanoprobe for hydrogen sulfide detection in the present invention, the preparation method of the Au@ZIF-8@Au used can be:

[0058] (1) Preparation of small-sized gold nanospheres with sodium citrate ligands: Add 100 μl of 10% 507 mM HAuCl to 100 ml of deionized water. 4 The solution was heated to boiling, and then 8 ml of 1% sodium citrate solution was added, and the solution was stirred vigorously at 600-800°C until the color of the solution changed to wine red, and then cooled to obtain small-sized gold nanospheres with sodium citrate ligands;

[0059] (2) Take 2 ml of the above sodium citrate ligand gold spheres, centrifuge at 6000-8000 rpm for 10-30 min, and redissolve the precipitate in 1 ml of water to obtain high-concentration sodium citrate ligand gold spheres; add 0.25 ml of the high-concentration gold nanospheres to 1 ml of DTPA-modified Au@ZIF-8 solution, incubate at room temperature (25°C) on a shaker at 400 rpm for 3 h, centrifuge at 6000 rpm for 10 min to remove excess small-sized gold nanospheres, take the precipitate and redissolve it in 1 ml of methanol to obtain a purple-black SERS nanoprobe for hydrogen sulfide detection.

[0060] The Au@ZIF-8@Au in this example was characterized by UV absorption spectrometer. Figure 2 shown.

[0061] The SERS nanoprobe for hydrogen sulfide detection prepared in this embodiment is used to detect hydrogen sulfide using the SERS spectral detection method, and the detection method is:

[0062] Prepare SERS detection samples. Mix the SERS nanoprobe for hydrogen sulfide detection prepared in this example with hydrogen sulfide simulation liquid in a volume ratio of 1:1. Use a 3mm capillary to absorb the mixed liquid, place it under a Raman instrument microscope, and detect the liquid sample under a 633nm wavelength laser. By analyzing the difference between the peak value of the Raman spectrum after detection and the peak value before detection, the corresponding Na 2 S solution concentration, and then the corresponding H 2 S gas concentration.

[0063] Wherein, the preparation method of the hydrogen sulfide simulated liquid is:

[0064] Will Na 2 S solid powder was dissolved in deionized water to prepare standard concentration solutions of 1 mM, 100 μM, 50 μM, 10 μM and 1 μM, respectively. 2 The concentration of S solution is the H generated by the powder dissolving in water. 2 S gas concentration.

[0065] Figure 3 The SERS method is used to detect hydrogen sulfide. It can be observed at 1200-1350cm -1 There are two peaks that gradually decrease. The SERS nanoprobe for hydrogen sulfide detection prepared by the method of the present invention can meet the requirements of SERS Raman spectroscopy detection method and has high accuracy and sensitivity.

[0066] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A SERS nanoprobe for hydrogen sulfide detection, characterized in that: The composite structure of the SERS nanoprobe for hydrogen sulfide detection is represented by Au@ZIF-8@Au; The SERS nanoprobe for hydrogen sulfide detection is a core-shell-satellite structure, wherein the core is a first gold nanosphere, the shell is a zeolite imidazole framework ZIF-8, and the outer portion of the shell is adsorbed with a second gold nanosphere; The first gold nanosphere is modified with dithiodiphenylazide DTPA, the surface ligand of the first gold nanosphere is hexadecyltrimethylammonium bromide CTAB, and the surface ligand of the second gold nanosphere is sodium citrate.

2. The SERS nanoprobe for hydrogen sulfide detection according to claim 1, characterized in that: The diameter of the first gold nanosphere is 70-80 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 540-545 nm; And / or, the overall diameter of the ZIF-8 coated first gold nanosphere is 80-110 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 550-560 nm; And / or, the diameter of the second gold nanosphere is 15-20 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 518-521 nm; And / or, the diameter of the SERS nanoprobe for hydrogen sulfide detection is 90-130 nm, and the longitudinal resonance absorption peak of the ultraviolet visible light absorption spectrum is 650-660 nm.

3. A method for preparing a SERS nanoprobe for hydrogen sulfide detection according to any one of claims 1 to 2, characterized in that: include: preparing a first gold nanosphere solution of CTAB ligand; A layer of ZIF-8 is coated on the first gold nanospheres of CTAB ligand to obtain Au@ZIF-8 solution; DTPA was modified on the surface of Au@ZIF-8 to obtain a DTPA-modified Au@ZIF-8 solution; The second gold nanospheres with sodium citrate ligands were adsorbed on the surface of Au@ZIF-8 modified with DTPA to obtain a SERS nanoprobe solution for hydrogen sulfide detection.

4. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 3, characterized in that: The method for preparing the first gold nanosphere solution of CTAB ligand comprises: At 23-26° C., HAuCl4 solution and CTAB solution were mixed evenly, and pre-chilled NaBH4 solution was added, and stirred at a speed of 500-550 rpm for 2-4 hours to prepare a seed solution, wherein the volume ratio of HAuCl4, CTAB and NaBH4 was (1-2): (30-60): (2.4-4.8); At 23-26° C., CTAB solution, HAuCl4 solution and ascorbic acid solution are sequentially added to deionized water, and stirred to obtain a growth solution, wherein the volume ratio of the deionized water, CTAB solution, HAuCl4 solution and ascorbic acid solution is (1-2): (0.05-0.1): (0.02-0.04): (0.07-0.14); Add the seed solution to the growth solution, invert for 5-15 seconds, place in 30-40°C warm water and let stand for 10-12 hours, separate the precipitate A by centrifugation, and disperse the precipitate A in deionized water to prepare a gold nanosphere solution, wherein the volume ratio of the seed solution to the growth solution is (1-2): (110-220), and the mass ratio of the precipitate A to deionized water is 1: (2-4); In a water bath at 40-50°C, a gold nanosphere solution is added to a mixed solution of CTAC, ascorbic acid and HAuCl4, stirred for 2-4 hours, and precipitate B is separated by centrifugation. Precipitate B is redissolved in a CTAB solution to prepare a gold nanopolyhedron solution, wherein the volume ratio of CTAC, ascorbic acid and HAuCl4 is (40-80): (1-2): (2-4), and the volume ratio of the mixed solution to the gold nanosphere solution is 1: (1.5-3) × 10 -3 , the mass ratio of the precipitate B to the CTAB solution is 1:(30-60); Add the HAuCl4 solution to the gold nanopolyhedron solution, stir for 1-3 hours in a water bath at 40-50°C, separate the precipitate C by centrifugation, and redissolve the precipitate C in deionized water to obtain the first gold nanosphere solution with CTAB ligand, wherein the volume ratio of the HAuCl4 solution to the gold nanopolyhedron solution is (1-2): (150-300), and the mass ratio of the precipitate C to deionized water is 1: (10-20).

5. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 3, characterized in that: The method comprises coating a layer of ZIF-8 on the first gold nanosphere of the CTAB ligand to obtain an Au@ZIF-8 solution, comprising: The first gold nanosphere solution of the CTAB ligand is added to the 2-methylimidazole solution, stirred evenly, and then a soluble zinc salt solution is added, stirred evenly and allowed to stand, and a precipitate D is separated by centrifugation. The precipitate D is washed with methanol and dissolved in a methanol solution to obtain an Au@ZIF-8 solution.

6. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 5, characterized in that: The preparation condition of coating a layer of ZIF-8 on the first gold nanosphere of CTAB ligand to obtain Au@ZIF-8 solution is room temperature; The volume ratio of the 2-methylimidazole solution, the first gold nanosphere AuNPs solution and the soluble zinc salt solution is (1-3): (1~2): (1-3); The step of stirring evenly and then leaving the mixture to stand comprises leaving the mixture to stand for 10-30 minutes.

7. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 3, characterized in that: Modifying the surface of Au@ZIF-8 with DTPA to obtain Au@ZIF-8 modified with DTPA, comprising: adding a DTPA solution to an Au@ZIF-8 solution, stirring at a constant temperature for 3-5 hours, centrifuging to separate a precipitate E, and redissolving the precipitate E in a methanol solution to obtain a DTPA-modified Au@ZIF-8 solution; The volume ratio of the DTPA solution to the Au@ZIF-8 solution is (1-2)×10 -2 :

1.

8. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 3, characterized in that: The second gold nanospheres with sodium citrate ligands are adsorbed on the surface of Au@ZIF-8 modified with DTPA to obtain a SERS nanoprobe for hydrogen sulfide detection, comprising: Add HAuCl4 solution to deionized water, heat to boiling, then add sodium citrate solution, stir until the solution changes to wine red, and cool to obtain a second gold nanosphere solution with sodium citrate ligand; The second gold nanosphere solution of the sodium citrate ligand is added to the DTPA-modified Au@ZIF-8 solution, stirred at 23-26° C., centrifuged to remove excess unadsorbed second gold nanospheres, and the precipitate F is taken out and redissolved in methanol to obtain a SERS nanoprobe solution for hydrogen sulfide detection.

9. The method for preparing a SERS nanoprobe for hydrogen sulfide detection according to claim 8, characterized in that: The volume ratio of the deionized water, HAuCl4 solution and sodium citrate solution is (50-100): (5-10)×10 -2 : (4-8); The volume ratio of the second gold nanosphere solution of the sodium citrate ligand to the Au@ZIF-8 solution modified by DTPA is (0.2-0.3): (1-1.5).

Images