A nano-composite substrate for SERS detection of chloramphenicol and a preparation method thereof

Abstract

The application discloses a nanocomposite substrate for SERS detection of chloramphenicol and a preparation method thereof. 17 The nanorod is a hierarchical structure with a nanorod as a framework and a MoS2 nanosheet layer coated outside the framework. The preparation method comprises the following steps: firstly, preparing MoS2 nanosheets; then, dispersing the MoS2 nanosheets in a solution formed by KOH and TiOSO4.xH2SO4.xH2O, collecting precipitates after high-temperature reaction; and finally, drying the precipitates after repeatedly cleaning the precipitates with deionized water and alcohol, so that the MoS2@K2Ti8O 17 nanocomposite substrate is obtained. 17 The nanocomposite substrate is used for SERS detection of chloramphenicol, has high sensitivity (10 ‑11 M) and good stability, and effectively improves the accuracy and reliability of SERS detection of chloramphenicol.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology and spectroscopic detection application, specifically relating to a nanocomposite substrate for SERS detection of chloramphenicol and its preparation method. Background Technology

[0002] Studies have shown that residual antibiotics in the environment can induce the generation and spread of drug-resistant bacteria and resistance genes. Their long-term presence often poses a greater potential threat to ecosystems than the direct toxic effects of the antibiotics themselves [Wei X, Liu C, Qin H, et al. J. Hazard. Mater. 2023, 443, 130299.]. Chloramphenicol ( Chloramphenicol Capsular dehydrogenase (CAP), as a representative broad-spectrum antibiotic, has been widely used in clinical and livestock farming fields due to its significant efficacy. However, CAP can enter the human body through multiple routes and accumulate in the body, potentially causing serious adverse reactions such as bone marrow suppression, aplastic anemia, leukemia, and kidney damage [Zhang H, Kang Z, Zhu H, et al. Sci. Total Environ. 2022, 443, 160284.]. Currently, CAP residues in the aquatic environment have become a hot topic of concern in environmental monitoring and public health fields both domestically and internationally. Establishing a sensitive and stable analytical method for CAP is of great significance.

[0003] Surface-enhanced Raman scattering (SERS) is an analytical technique that utilizes the enhanced Raman scattering signal generated when analytes are adsorbed or approach the surface of an active substrate to achieve trace spectroscopic detection of substances. With its outstanding advantages such as high sensitivity, rapid response, and non-destructive testing, it has shown broad application prospects in materials science, environmental monitoring, and pharmaceutical analysis [Quan Y, Yao J, Yang S, et al. J. Hazard. Mater. 2020, 391, 122222.]. However, in practical applications, the performance of SERS detection largely depends on the SERS activity of the substrate material and its ability to bind / adsorb the analyte.

[0004] To further enhance the application of SERS technology in trace detection, researchers have begun to focus on the application of novel composite nanomaterials in substrates. In recent years, transition metal sulfides have shown great potential in surface-enhanced spectroscopy and chemical sensing due to their unique layered structure, excellent electron transport properties, and large specific surface area. Among them, molybdenum disulfide (MoS2) possesses abundant surface active sites and excellent charge transfer capabilities, which can enhance Raman signals and promote the adsorption of target molecules to a certain extent. However, single-material molybdenum disulfide (MoS2) still faces certain limitations in terms of stability, enhancement effect, and structural controllability. Meanwhile, potassium titanate (K2Ti8O)... 17 As an inorganic material with a unique one-dimensional structure, molybdenum disulfide (MoD) possesses high chemical stability, a large specific surface area, and excellent structural support properties, providing a stable loading platform for active components. However, to date, there are no reports on the application of molybdenum disulfide and potassium titanate nanocomposites to SERS substrates for trace detection of chloramphenicol. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned technical problems existing in the prior art by providing a nanocomposite substrate for SERS detection of chloramphenicol and its preparation method.

[0006] The technical solution of this invention is: a nanocomposite substrate for SERS detection of chloramphenicol, which is a nanocomposite material composed of molybdenum disulfide and potassium titanate, wherein the nanocomposite material is K2Ti8O 17 The structure consists of nanorods as the framework, with MoS2 nanosheets encapsulated on the outside.

[0007] A method for preparing the above-mentioned nanocomposite substrate for SERS detection of chloramphenicol is carried out according to the following steps: Step 1. Prepare MoS2 nanosheets; Step 2. Weigh KOH and TiOSO4•xH2SO4•xH2O and dissolve them in distilled water to obtain a mixed solution; then disperse the prepared MoS2 into the mixed solution, wherein the mass fraction of MoS2 in the mixed solution is 0.7~0.8%; after stirring magnetically for 1~2 hours, transfer to an autoclave and react at 180~200℃ for 22~24 hours; Step 3. Collect the precipitate, wash it repeatedly with deionized water and alcohol, and then dry it thoroughly in an oven at 60-80℃ to obtain the nanocomposite material MoS2@K2Ti8O. 17 .

[0008] The preferred step 2 involves weighing 3.3g KOH and 1.92g TiOSO4•xH2SO4•xH2O and dissolving them in 50-60 mL of distilled water, and dispersing MoS2 into the mixed solution according to a mass fraction of 0.75% in the mixed solution.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes MoS2 nanosheets and K2Ti8O 17 The nanostructure composite forms a stable interface structure, which effectively increases the active sites on the material surface, providing more active sites for the adsorption of the target molecule CAP, thereby improving the SERS response of the substrate. 2. This invention utilizes MoS2 nanosheets and K2Ti8O 17 The interfacial coupling between nanostructures enhances the charge transfer effect, significantly increasing the chemical enhancement contribution. This results in a stronger enhancement of the Raman signal of the target molecule by the obtained SERS substrate, thereby improving detection sensitivity. The CAP detection sensitivity can reach 10. -11 M; 3. The MoS2@K2Ti8O constructed in this invention 17 Nanocomposite substrates exhibit good structural stability and signal repeatability, demonstrating excellent reliability in the detection of trace CAP, which is beneficial for achieving accurate detection of trace CAP. Attached Figure Description

[0010] Figure 1 The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 Scanning electron microscope and transmission electron microscope images of nanocomposite substrates.

[0011] Figure 2 The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 XPS spectra of nanocomposite substrates.

[0012] Figure 3 The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 Nanocomposite substrates were used to detect SERS spectra of different concentrations of CAP.

[0013] Figure 4 The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 Intrinsic Raman spectra of nanocomposite substrate stability experiment and SERS spectra of CAP molecules. Detailed Implementation

[0014] A nanocomposite substrate for SERS detection of chloramphenicol according to the present invention is prepared by following the steps below: Step 1. MoS2 nanosheets were prepared according to the literature [Quan Y, Yao J, Sun Y, et al. Sensors & Actuators: B. Chemical, 2021, 327, 128903.]. The specific preparation steps were as follows: 500 mg sodium molybdate tetrahydrate, 700 mg thiourea and 500 mg citric acid were dissolved in 70 mL of deionized water. The mixture was magnetically stirred for 1 hour and then transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reactor. The reaction was carried out at 220 °C for 24 hours. After natural cooling, the black precipitate was collected. After being washed three times with deionized water and alcohol, the precipitate was dried in an oven at 60 °C for 8 hours to obtain MoS2 nanomaterials. Step 2. Weigh 3.3g KOH and 1.92g TiOSO4·xH2SO4·xH2O (purity 93%), dissolve them in 50 mL distilled water to obtain a mixed solution; then weigh the MoS2 nanomaterials obtained in Step 1 and disperse them in the above mixed solution so that the mass fraction of MoS2 in the mixed solution is 0.75%; after stirring magnetically for 1 hour, transfer the mixture to a 100 mL polytetrafluoroethylene-lined autoclave and react at 200℃ for 24 hours. Step 3. Scrape and collect the gray precipitate along the inner wall and bottom of the PTFE-lined autoclave. After washing it three times with deionized water and alcohol, dry it in an oven at 60°C for 8 hours to obtain MoS2@K2Ti8O. 17 Nanocomposite substrate.

[0015] The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the nanocomposite substrate are as follows: Figure 1 As shown. Figure 1 (a) SEM image; (b) TEM image. From Figure 1 It can be seen that the prepared MoS2@K2Ti8O 17 The nanocomposite substrate is based on K2Ti8O 17 The framework consists of nanorods, which are uniformly coated with MoS2 nanosheets in a hierarchical structure with a rough surface and abundant layered edges.

[0016] The MoS2@K2Ti8O obtained in the embodiments of the present invention 17 XPS spectra of nanocomposite substrates as follows Figure 2 As shown. Figure 2 (a) Full spectrum; (b) Mo3d fine spectrum; (c) S 2p fine spectrum; (d) K 2p fine spectrum; (e) Ti 2p fine spectrum; (f) O 1s fine spectrum. From Figure 2 It can be seen that MoS2 and K2Ti8O17 The composite was successful, forming MoS2@K2Ti8O 17 Nanocomposite substrate. The Mo and S peaks are relatively uniform, while MoS2 shows a slight shift, indicating that MoS2 and K2Ti8O are well integrated. 17 There are interfacial electronic interactions, which are beneficial for interfacial charge transport.

[0017] experiment: 1.MoS2@K2Ti8O 17 CAP sensitivity experiment of nanocomposite substrate detection The MoS2@K2Ti8O obtained using the embodiments of the present invention 17 Nanocomposite substrate, for 10 -5 ~10 -11 The CAP was tested within the M concentration range, following these steps: (1) Prepare a clean glass slide for later use; (2) Using a solvent composed of deionized water and alcohol in a 1:1 ratio, different concentrations (10) were prepared. -5 -10 -11 The CAP solution to be tested (M); (3) Weigh 5 mg of MoS2@K2Ti8O 17 The nanocomposite substrates were dispersed in 10 mL of CAP solutions of different concentrations and shaken thoroughly for 12 hours to obtain mixtures. (4) Take 1 mL of the mixture and drop it onto the prepared glass slide after step (4). After it is naturally dried, use a Raman spectrometer to detect SERS.

[0018] SERS detection spectrum as follows Figure 3 As shown. The results indicate that the MoS2@K2Ti8O of the embodiment of the present invention... 17 The nanocomposite substrate exhibits excellent detection sensitivity for CAP molecules, with a detection limit as low as 10. -11 M.

[0019] 2.MoS2@K2Ti8O 17 Stability experiment of nanocomposite substrate MoS2@K2Ti8O with different storage times (0-3 months) 17 Intrinsic Raman spectroscopy experiments were conducted on the nanocomposite substrate, and the intrinsic Raman spectra are shown below. Figure 4 As shown in (a). The results show that under different storage times, MoS2@K2Ti8O 17 The intrinsic Raman peak positions and shapes of the nanocomposite substrate remain basically unchanged, indicating good structural stability.

[0020] MoS2@K2Ti8O with different storage times (0-3 months) 17 Nanocomposite substrate for SERS detection of CAP molecules (10 -7 M) Experiment, SERS spectrum as shown Figure 4 As shown in (b). The results indicate that, under different storage times, MoS2@K2Ti8O 17 The SERS characteristic peak positions of the nanocomposite substrate detected by CAP were basically consistent, with only slight fluctuations in signal intensity, indicating that MoS2@K2Ti8O 17 It still exhibits high SERS activity after a 3-month storage period.

Claims

1. A nanocomposite substrate for SERS detection of chloramphenicol, characterized in that... It is a nanocomposite material composed of molybdenum disulfide and potassium titanate, wherein the nanocomposite material is K2Ti8O 17 The structure consists of nanorods as the framework, with MoS2 nanosheets encapsulated on the outside.

2. A method for preparing a nanocomposite substrate for SERS detection of chloramphenicol as described in claim 1, characterized in that... Follow these steps in sequence: Step 1. Prepare MoS2 nanosheets; Step 2. Weigh KOH and TiOSO4•xH2SO4•xH2O and dissolve them in distilled water to obtain a mixed solution; then disperse the prepared MoS2 into the mixed solution, wherein the mass fraction of MoS2 in the mixed solution is 0.7~0.8%; After stirring magnetically for 1-2 hours, transfer the mixture to an autoclave and react at 180-200℃ for 22-24 hours. Step 3. Collect the precipitate, wash it repeatedly with deionized water and alcohol, and then dry it thoroughly in an oven at 60-80℃ to obtain the nanocomposite material MoS2@K2Ti8O. 17 .

3. The method for preparing the nanocomposite substrate for SERS detection of chloramphenicol according to claim 2, characterized in that... Step 2 involves weighing 3.3g KOH and 1.92g TiOSO4•xH2SO4•xH2O and dissolving them in 50-60 mL of distilled water, and dispersing MoS2 into the mixed solution according to the mass fraction of MoS2 in the mixed solution being 0.75%.

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