Preparation and application of AuNPs@MBA@HPAM raman substrate
By preparing AuNPs@MBA@HPAM Raman substrates and combining them with SERDS technology, the problems of accuracy and speed in Pb²+ detection in complex samples were solved, realizing simple and efficient lead ion detection suitable for on-site detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ACADEMY OF MILITARY MEDICAL SCIENCES
- Filing Date
- 2026-03-13
- Publication Date
- 2026-07-10
Smart Images
Figure CN122361385A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heavy metal detection, specifically to the preparation and application of AuNPs@MBA@HPAM Raman substrates. Background Technology
[0002] Lead ions (Pb²) + Lead, a highly toxic heavy metal pollutant, is widely found in industrial wastewater, agricultural runoff, and atmospheric deposition. It is difficult to degrade and easily accumulates, and can be transferred and enriched in the human body through biological and food chains. Long-term exposure can cause serious health problems. Although the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) have set safety limits for lead in drinking water (0.01 mg / L) and blood (0.1 mg / L), respectively, studies have shown that even trace amounts of lead exposure can cause irreversible health damage. Traditional Pb 2+ The detection methods for Pb mainly include atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). While these techniques offer high sensitivity and accuracy, they typically require complex sample pretreatment, expensive instruments, and specialized operators, making them unsuitable for rapid on-site detection and real-time monitoring. Therefore, it is crucial to develop a highly sensitive, low-cost, and suitable method for rapid on-site detection of Pb. 2+ Detection technology is of great significance for environmental safety and public health.
[0003] Surface-enhanced Raman spectroscopy (SERS) is a fundamental surface-sensitive technique that enhances Raman scattering by modifying or adsorbing target molecules onto a specific surface. It enables stable, rapid, label-free, and non-destructive detection of various target molecules. Compared to traditional Raman spectroscopy, the SERS effect can amplify the Raman signal intensity by 10-1. 2 ~10 14 This significantly expands the application range of Raman spectroscopy. However, this technique is susceptible to background fluorescence interference, and its ability to suppress background fluorescence in complex sample systems remains significantly insufficient.
[0004] Therefore, we investigate the application of Pb² + Rapid SERS detection substrates and Pb² detection in complex samples + The detection method is of positive significance for the protection of environmental health and human health. Summary of the Invention
[0005] The technical problem to be solved by this invention is to provide an AuNPs@MBA@HPAM Raman substrate to achieve Pb 2+ It enables rapid detection and solves the problem that surface-enhanced Raman spectroscopy (SERS) cannot accurately detect complex samples in existing technologies.
[0006] On the one hand, the present invention provides a method for preparing AuNPs@MBA@HPAM Raman substrates, the preparation method comprising the following steps: Preparation steps of gold nanoparticle solution: Synthesis of gold nanoparticle solution; The coating steps for 4-mercaptobenzoic acid are as follows: 4-mercaptobenzoic acid is dissolved in an organic solvent to obtain a 4-mercaptobenzoic acid mother liquor; the 4-mercaptobenzoic acid mother liquor is diluted with pure water to obtain a 4-mercaptobenzoic acid working solution; the 4-mercaptobenzoic acid working solution is added to the gold nanoparticle solution and stirred to obtain an AuNPs@MBA mixture; the AuNPs@MBA mixture is centrifuged to obtain an AuNPs@MBA precipitate; the AuNPs@MBA precipitate is washed and resuspended in pure water to obtain an AuNPs@MBA solution. The coating steps for amino-terminated hyperbranched polyamides are as follows: The amino-terminated hyperbranched polyamides are dissolved in pure water to obtain an amino-terminated hyperbranched polyamide solution; under stirring conditions, the amino-terminated hyperbranched polyamide solution is added to the AuNPs@MBA solution and incubated to obtain an incubation product; the incubation product is centrifuged to obtain an AuNPs@MBA@HPAM precipitate; the AuNPs@MBA@HPAM precipitate is resuspended in pure water to obtain an AuNPs@MBA@HPAM Raman substrate.
[0007] Furthermore, the stirring in the 4-mercaptobenzoic acid coating step is magnetic stirring.
[0008] Furthermore, the stirring in the coating step of the amino-terminated hyperbranched polyamide is magnetic stirring.
[0009] Furthermore, in the preparation step of the gold nanoparticle solution, gold nanoparticle solution is synthesized by sodium citrate reduction method; the synthesis of gold nanoparticle solution by sodium citrate reduction method includes: dissolving trisodium citrate in pure water to obtain trisodium citrate solution; heating the trisodium citrate solution to boiling, then adding chloroauric acid to the boiling trisodium citrate solution to obtain a reaction system; continuously heating the reaction system to boiling until the reaction system changes from colorless to wine red, and then continuing the reaction under boiling conditions for 15-30 minutes to obtain gold nanoparticle solution.
[0010] Furthermore, in the preparation step of the gold nanoparticle solution, the final concentration of trisodium citrate in the reaction system is 0.1-0.2 mg / mL, and the final concentration of chloroauric acid is 0.06-0.09 mg / mL.
[0011] Furthermore, in the 4-mercaptobenzoic acid coating step, the volume ratio of the gold nanoparticle solution to the 4-mercaptobenzoic acid solution is 1:0.5-1; and the concentration of the 4-mercaptobenzoic acid solution is 1-3 mM.
[0012] Furthermore, in the coating step of 4-mercaptobenzoic acid, the stirring time is 0.5-1.5 h.
[0013] Furthermore, in the coating step of the amino-terminated hyperbranched polyamide, the volume ratio of the AuNPs@MBA solution to the amino-terminated hyperbranched polyamide solution is 1:1-5; and the concentration of the amino-terminated hyperbranched polyamide solution is 5-10 mg / mL.
[0014] Furthermore, in the coating step of amino-terminated hyperbranched polyamide, the incubation is carried out on a shaker at a speed of 80-90 rpm and a temperature of room temperature (20-30℃); the incubation time is 6-12 h.
[0015] On the other hand, the present invention provides an AuNPs@MBA@HPAM Raman substrate, which is prepared by the above-described preparation method.
[0016] On the other hand, the present invention provides AuNPs@MBA@HPAM Raman substrates prepared by the above preparation method, or AuNPs@MBA@HPAM Raman substrates used to detect Pb in samples. 2+ Applications in concentration.
[0017] Furthermore, the sample includes water and / or plasma.
[0018] Furthermore, the detection methods used in the application include Raman detection and / or ultraviolet absorption spectroscopy detection.
[0019] On the other hand, the present invention provides a method for detecting Pb 2+ The method involves using an AuNPs@MBA@HPAM Raman substrate prepared by the above-described preparation method, or mixing the AuNPs@MBA@HPAM Raman substrate with an equal volume of the sample to be tested to obtain a detection system. The detection system is then placed on a Raman spectrometer, and Raman spectra are obtained at excitation wavelengths of 784.5 nm and 785.5 nm. The Raman spectrometer automatically normalizes, reconstructs, subtracts, and corrects the baseline of the obtained Raman spectra to obtain differential Raman spectra. The presence of Pb in the sample is determined based on the intensity changes of the differential Raman spectral signal. 2+ .
[0020] Furthermore, the determination method is based on comparing the presence of Pb with the blank control group. 2+ The intensity of the differential Raman spectral signal produced by the sample will be enhanced.
[0021] The technical solution of this invention has the following advantages: (1) The AuNPs@MBA@HPAM Raman substrate provided by this invention has a simple synthesis method that can be completed at room temperature. During the preparation process, 4-mercaptobenzoic acid (4-MBA) is introduced. 4-MBA can form stable Au-S covalent bonds with the surface of gold nanoparticles through its thiol group (-SH), achieving stable binding on the surface of the gold nanoparticles. Subsequently, the carboxyl group (-COOH) of 4-MBA undergoes an amidation reaction with the amino group (-NH2) of amino-terminated hyperbranched polyamide (HPAM), grafting the amino-rich HPAM polymer onto the surface of the nanoparticles. The entire preparation process is based on the self-assembly of the components, requiring no complex external operations or processing steps. This substrate integrates Raman spectral signal amplification, the stable spectral fingerprint characteristics of 4-mercaptobenzoic acid (4-MBA), and the affinity of amino-terminated hyperbranched polyamide (HPAM) for Pb²⁺. + It exhibits selective chelation ability, has a simple preparation process with good repeatability, and can achieve dual-mode detection of "Raman + UV".
[0022] (2) The Pb² provided by the present invention + The detection method employs a dual-mode approach, utilizing both Raman spectroscopy (SERDS) and ultraviolet-visible spectroscopy (UV-vis). These two methods corroborate and complement each other, effectively improving the accuracy of the results. Furthermore, the method is simple, efficient, and rapid, with the detection time controlled within 10 minutes.
[0023] (3) The Pb² provided by the present invention + The detection method further employs a dual-wavelength excitation strategy of shift-excited differential Raman spectroscopy (SERDS) based on traditional surface-enhanced Raman spectroscopy (SERS): the original Raman spectra are acquired at excitation wavelengths of 784.5 nm and 785.5 nm, respectively. Then, the data is processed through a systematic data processing flow (normalization, spectral reconstruction, baseline correction) to effectively subtract background fluorescence, and finally a pure differential Raman spectrum is obtained. The method has a significant effect on suppressing fluorescence background in the detection of complex samples. Attached Figure Description
[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0025] Figure 1 Design flowchart for AuNPs@MBA@HPAM Raman substrate; Figure 2The images show the TEM results for AuNPs@MBA@HPAM; where A and C are the TEM images for AuNPs; and B and D are the TEM images for AuNPs@MBA@HPAM. Figure 3 Figures show the results of particle size, zeta potential, and UV-vis characterization analysis; where A is the bar chart of AuNPs particle size; B is the bar chart of AuNPs@MBA@HPAM particle size; C is the bar chart of zeta potential of AuNPs, AuNPs@MBA, and AuNPs@MBA@HPAM; and D is the UV-vis spectrum. Figure 4 DES elemental analysis diagram for AuNPs@MBA@HPAM; Figure 5 This document presents the workflow and spectral comparison results for SERDS (Self-Excited Differential Raman Spectroscopy). Figure A shows the SERDS workflow: raw spectra are acquired at excitation wavelengths of 784.5 nm and 785.5 nm, followed by normalization, reconstruction, differential subtraction, and baseline correction to obtain pure Raman spectra. Figure B shows a comparison of conventional Raman spectra (top) and differential Raman spectra (bottom). Figures C and D show AuNPs@MBA@HPAM spectra at different Pb concentrations obtained using differential Raman and conventional Raman spectroscopy. 2+ SERDS spectrum in presence (illustration shows 1074 cm⁻¹) -1 (Magnified view of the characteristic peak region) Figure 6 Figure 1 shows the Raman performance evaluation results of AuNPs@MBA@HPAM; where A and B are the SERDS plots and intensity contour plots of AuNPs@MBA@HPAM stability; C and D are the SERDS plots and intensity contour plots of AuNPs@MBA@HPAM repeatability; E is a bar chart of relative standard error (RSD) values; F is the effect of AuNPs@MBA@HPAM on Pb in the presence of other metal ions. 2 + Selective bar chart; Figure 7 For different concentrations of Pb 2+ The detection results of AuNPs@MBA@HPAM in solution; where A represents different concentrations of Pb. 2 + SERDS spectra of AuNPs@MBA@HPAM in solution; B represents the SERDS intensity versus different concentrations of Pb. 2+ Regression equations and standard curves between solutions; C represents different concentrations of Pb. 2+ UV-Vis spectra of AuNPs@MBA@HPAM in solution; D represents the absorption spectral values versus different concentrations of Pb. 2+ Regression equations and standard curves between solutions; Figure 8 Pb in AuNPs@MBA@HPAM nanoprobes 2+ Figure showing the results of the mechanism study on induced SERDS enhancement; where A and C represent Pb. 2+ DFT-optimized molecular structures before and after coordination; B and D are molecular electrostatic potential (MESP) plots; E is Pb 2+ Quantum chemical parameters before and after coordination; F and G are Pb 2+ SEM images of induced nanoparticle aggregation; H and I represent the addition of Pb. 2+ Post-particle size distribution map; J represents the Pb content of AuNPs, AuNPs@MBA, and AuNPs@MBA@HPAM. 2+ Comparison of capture efficiency; Figure 9 This is a graph evaluating the practical applicability of the AuNPs@MBA@HPAM dual-mode detection; where A and B show the 1074 cm⁻¹ of the water sample measured by SERDS and UV-vis spectroscopy, respectively. -1 A bar chart showing the peak intensity and absorption spectral values at 1074 cm⁻¹; D and E show the peak intensity and absorption spectral values of the plasma sample measured by SERDS and UV-vis spectroscopy, respectively. -1 A bar chart of peak intensity and absorption spectral values; C and F analyze and compare the SERDS, UV-vis, and ICP-MS results of water and plasma samples. Detailed Implementation
[0026] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.
[0027] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0028] Source of materials used in the experiment: All chemical reagents were of analytical grade and were not further purified before use. Trisodium citrate was purchased from Shanghai Jizhi Biotechnology Co., Ltd.; chloroauric acid (HAuCl4) was purchased from Sinopharm Chemical Reagent Co., Ltd.; amino-terminated hyperbranched polyamide (HPAM), 4-mercaptobenzoic acid (4-MBA), and Pb were also used. 2+Standard solutions, chromium ion standard solutions, arsenic ion standard solutions, mercury ion standard solutions, sodium chloride, calcium chloride, magnesium chloride, and potassium iodide were all purchased from Shanghai McLean Biochemical Technology Co., Ltd.; all experiments used ultrapure water prepared by the Millipore ultrapure water system.
[0029] Example 1. AuNPs@MBA@HPAM Raman substrate and its preparation This invention provides an AuNPs@MBA@HPAM Raman substrate, the preparation method of which includes the following steps (the design concept of the AuNPs@MBA@HPAM Raman substrate is described in [link to documentation]). Figure 1 ): (1) Dissolve 15 mg of trisodium citrate completely in 100 mL of pure water to obtain a trisodium citrate solution; heat the trisodium citrate solution to boiling under strong magnetic stirring (500 rpm) to obtain a boiling trisodium citrate solution. (2) Add 7.5 mg of chloroauric acid (HAuCl4) to the boiling trisodium citrate solution (adjust the magnetic stirring speed to 1000 rpm), continue heating until the colorless solution gradually turns wine red, and maintain for 20 min to obtain AuNPs solution; (3) Dissolve 16 mg of 4-mercaptobenzoic acid (4-MBA) in 10 mL of methanol to obtain 4-mercaptobenzoic acid mother liquor; add 90 mL of pure water to the 4-mercaptobenzoic acid mother liquor to obtain 1 mM 4-mercaptobenzoic acid working solution; sonicate the AuNPs solution for 20 min, and then slowly add 50 mL of 1 mM 4-mercaptobenzoic acid working solution dropwise under magnetic stirring (magnetic stirring speed is 350 rpm) for 1 h to obtain AuNPs@MBA mixture; (4) Centrifuge the AuNPs@MBA mixture to obtain AuNPs@MBA precipitate; wash the AuNPs@MBA precipitate twice with pure water, resuspend it in 10 mL of pure water, and sonicate for 10 min for later use to obtain AuNPs@MBA solution; (5) Dissolve 200 mg of amino-terminated hyperbranched polyamide (HPAM) in 20 mL of pure water and shake until fully dissolved to obtain HPAM solution; under magnetic stirring (magnetic stirring speed is 350 rpm), slowly add AuNPs@MBA solution to 10 mL of HPAM solution. After the addition is completed, transfer to a shaker (85 rpm) and incubate overnight (12 h) at room temperature (25℃) to obtain incubation product; centrifuge the incubation product to obtain AuNPs@MBA@HPAM precipitate. Wash the AuNPs@MBA@HPAM precipitate twice with pure water, resuspend it with 5 mL of pure water, and sonicate for 10 min to finally obtain AuNPs@MBA@HPAM Raman substrate solution.
[0030] Experimental Example 1. Characterization Analysis of AuNPs@MBA@HPAM Raman Substrates This experimental example characterizes and analyzes the AuNPs solution and AuNPs@MBA@HPAM Raman substrate solution prepared in Example 1, as follows: 1. TEM characterization analysis The surface morphology and elemental composition of the nanoparticles in the AuNPs solution and AuNPs@MBA@HPAM Raman substrate solution prepared in Example 1 were characterized using a high-resolution transmission electron microscope (HR-TEM, FEITecnai G2 F30) equipped with energy dispersive X-ray spectroscopy (EDX).
[0031] The results are as follows Figure 2 As shown, the AuNPs nanoparticles have similar morphologies to the AuNPs@MBA@HPAM nanoparticles, both exhibiting a clear spherical structure. This indicates that the coating process of 4-mercaptobenzoic acid (4-MBA) and amino-terminated hyperbranched polyamide (HPAM) did not significantly affect the morphology and structure of the AuNPs nanoparticles. Simultaneously, the AuNPs@MBA@HPAM nanoparticles have distinct transparent rings around them (such as...). Figure 2 (as shown by the arrow in D), while AuNPs nanoparticles do not have this structure (as shown by the arrow in D). Figure 2 As shown in Figure C), this demonstrates that 4-MBA and HPAM have been successfully coated onto the surface of AuNPs nanoparticles in AuNPs@MBA@HPAM nanoparticles.
[0032] 2. Characterization analysis of particle size, zeta potential and UV-vis. The particle size distribution of AuNPs and AuNPs@MBA@HPAM nanoparticles was analyzed using TEM images obtained with Nano Measurer 1.2 software to obtain their particle sizes. The zeta potentials of AuNPs solutions and AuNPs@MBA@HPAM Raman substrate solutions were measured using dynamic light scattering (DLS) to obtain their zeta potentials. The absorption spectra of AuNPs solutions and AuNPs@MBA@HPAM Raman substrate solutions were obtained using a Shimadzu 2450 UV-Vis spectrophotometer to obtain their UV-Vis absorption spectra.
[0033] The results are as follows Figure 3 As shown, particle size analysis using TEM results indicates that the particle size of AuNPs nanoparticles is 16.08 ± 1.91 nm, and the particle size of AuNPs@MBA@HPAM nanoparticles is 18.35 ± 1.65 nm, slightly larger than the particle size of unmodified AuNPs nanoparticles (e.g., ...). Figure 3 (As shown in A and B); the zeta potential test results show that the zeta potentials of AuNPs nanoparticles, AuNPs@MBA nanoparticles, and AuNPs@MBA@HPAM nanoparticles are -1.33 mV, -7.34 mV, and 31.05 mV, respectively, with significant changes in potential values (e.g., as shown in A and B). Figure 3 As shown in C); UV-Vis absorption spectroscopy results show that AuNPs nanoparticles exhibit an absorption peak at 520 nm, while AuNPs@MBA nanoparticles show absorption peaks at 260 nm, 520 nm, and 750 nm. After HPAM modification, the peak at 260 nm of AuNPs@MBA nanoparticles broadens, and the absorption peaks at 520 nm and 750 nm merge to form a new broad absorption peak, further demonstrating that 4-MBA and HPAM in AuNPs@MBA@HPAM nanoparticles have been successfully coated on the surface of AuNPs nanoparticles (as shown in C). Figure 3 As shown in D).
[0034] 3. EDS elemental analysis and characterization analysis Elemental composition analysis of AuNPs@MBA@HPAM Raman substrate solutions was performed using energy-dispersive spectroscopy (EDS).
[0035] The results are as follows Figure 4As shown, three characteristic elements, Au, S, and N, were detected in the AuNPs@MBA@HPAM nanoparticles; the Au element originated from AuNPs, the S element from 4-mercaptobenzoic acid (4-MBA), and the N element from amino-terminated hyperbranched polyamide (HPAM). These EDS results further confirm that 4-MBA and HPAM have been successfully coated onto the surface of the AuNPs nanoparticles.
[0036] Experimental Example 2. Workflow and Spectral Comparison of Displacement Excited Differential Raman Spectroscopy (SERDS) To investigate the advantages of differential Raman spectroscopy (SERDS), the AuNPs@MBA@HPAM Raman substrate solution was further analyzed using both conventional Raman spectroscopy (SERS) and differential Raman spectroscopy (SERDS). The AuNPs@MBA@HPAM Raman substrate solution was placed on a Jianzhi portable differential Raman spectrometer for simultaneous detection, allowing for the acquisition of both SERS and SERDS spectra. The working principle of differential Raman spectroscopy is as follows: Figure 5 As shown in A, ordinary Raman spectra were obtained at excitation wavelengths of 784.5 nm and 785.5 nm. Based on the wavelength independence of fluorescence background and the shift dependence of Raman peaks, the ordinary Raman spectra were normalized, reconstructed, subtracted, and baseline corrected to obtain pure differential Raman spectra.
[0037] The results show that the differential Raman spectroscopy based on the AuNPs@MBA@HPAM Raman substrate has significant advantages over conventional Raman spectroscopy; conventional Raman spectroscopy suffers from baseline drift due to fluorescence. Figure 5 The upper part of Figure B) affected the 4-MBA characteristic peak (1074 cm⁻¹). -1 and 1582 cm -1 The reproducibility and quantitative accuracy of differential Raman spectroscopy; while differential Raman spectroscopy ( Figure 5 (The figure below in B) successfully suppressed background fluorescence, with a smooth and stable baseline, clear characteristic peaks, and significantly improved reproducibility.
[0038] To evaluate the differential Raman spectroscopy for Pb² + The response performance was analyzed in Pb² + Spectral evolution at concentrations of 0 to 1 μg / mL, conventional Raman spectroscopy (such as...) Figure 5 In the C-shaped spectrum, fluorescence background interference hinders accurate signal quantization and masks the correlation between peak intensity and concentration; while differential Raman spectroscopy (as shown in Figure C) Figure 5 In (as shown in D), 1074 cm -1 The intensity of the characteristic peaks increased significantly in a concentration-dependent manner, with a flat baseline and sharp peak shape.
[0039] The above results all indicate that differential Raman spectroscopy effectively overcomes fluorescence background interference in complex matrices, significantly improves the signal-to-noise ratio and reproducibility, and provides a basis for the development of Pb-based fluorescence microarrays. 2+ This has laid a solid foundation for highly sensitive quantitative detection.
[0040] Experimental Example 3. Detection of the stability, repeatability, and selectivity of AuNPs@MBA@HPAM Raman substrates. In this experiment, the AuNPs@MBA@HPAM Raman substrate solution was subjected to differential Raman spectroscopy (SERDS) detection on days 1, 3, 5, 7, 8, 9, and 10 to evaluate the stability of the AuNPs@MBA@HPAM Raman substrate. Furthermore, 15 consecutive differential Raman spectroscopy (SERDS) detections were performed to evaluate the detection of Pb based on the AuNPs@MBA@HPAM Raman substrate. 2+ Concentration repeatability.
[0041] At different time points (days 1, 3, 5, 7, 8, 9, and 10), 0.5 mL of the AuNPs@MBA@HPAM Raman substrate solution prepared in Example 1 was taken and subjected to seven differential Raman spectroscopy (SERDS) measurements. The stability test results of the AuNPs@MBA@HPAM Raman substrate are as follows. Figure 6 As shown in A, B, and E, the AuNPs@MBA@HPAM Raman substrate maintains stable differential Raman spectroscopy (SERDS) signals over 10 days with an RSD value of less than 10%, demonstrating good long-term stability.
[0042] By taking 0.5 mL of the AuNPs@MBA@HPAM Raman substrate solution prepared in Example 1 and 0.5 mL of Pb 2+ The solution (1 μg / mL, obtained by diluting a lead ion standard solution with water) was mixed and then subjected to 15 consecutive differential Raman spectroscopy (SERDS) measurements. The results are as follows: Figure 6 As shown in C, D, and E, the AuNPs@MBA@HPAM Raman substrate is used to analyze the analyte Pb. 2+ The differential Raman spectroscopy (SERDS) detection signals showed good consistency, with RSD values all less than 10%, and the AuNPs@MBA@HPAM Raman substrate exhibited good repeatability.
[0043] To verify the detection selectivity, As was selected. 3+ Ca 2+ Cr 6+ Hg 2+ K + Na + and Mg 2+A total of 7 potential interfering metal ions (each with a concentration of 1 μg / mL, obtained by diluting chromium ion standard solutions, arsenic ion standard solutions, and mercury ion standard solutions with water; and prepared by dissolving sodium chloride, calcium chloride, magnesium chloride, and potassium iodide in water) were identified, along with Pb. 2+ Selective testing was performed by mixing the aforementioned interfering metal solution and lead solution with an equal volume of AuNPs@MBA@HPAM Raman substrate solution to obtain test samples. These samples were then placed on a Jianzhi portable differential Raman spectrometer for differential Raman spectroscopy (SERDS) detection. The results are as follows: Figure 6 As shown in F, when Pb 2+ Concentration (10) -4 When the concentration of AuNPs@MBA@HPAM Raman substrate was four orders of magnitude lower than that of interfering ions (1 μg / mL), the concentration at 1074 cm⁻¹ was significantly lower. -1 The differential Raman spectroscopy (SERDS) signal intensity generated at this site is still significantly higher than that of all other metal ions, indicating that the AuNPs@MBA@HPAM Raman substrate is effective against Pb. 2+ It has excellent selectivity and anti-interference ability.
[0044] Experimental Example 4. Pb based on AuNPs@MBA@HPAM Raman substrate 2+ Dual-mode (SERS and UV-vis) quantitative detection The reaction system was obtained by mixing equal volumes of AuNPs@MBA@HPAM Raman substrate solution and lead solutions of different concentrations. The reaction system contained Pb. 2+ The final concentration is as follows Figure 7 As shown in A and C, the SERDS and UV-vis measurements of the above reaction system were then performed.
[0045] The results are as follows Figure 7 As shown, the changes in the 4-MBA peak intensity and the absorption peak changes of AuNPs@MBA@HPAM indirectly reflect the Pb content. 2+ Does it exist and how does its concentration change? When Pb 2+ The concentration is at 10 -6 ~10 -1 Within the dynamic range of μg / mL, 1074 cm -1 SERDS intensity at point and Pb² + The logarithm of the concentration shows a strong linear relationship, with the coefficient of determination (R²) indicating a strong linear relationship. 2 ) is 0.90 (e.g. Figure 7 (As shown in A and B). All samples exhibited broad absorption peaks in the 500-850 nm UV-vis spectrum, and when Pb... 2+ The concentration is at 10 -5 Within a dynamic range of ~1 μg / mL, the absorbance value of the absorption peak is related to Pb².+ The logarithm of the concentration shows a strong linear relationship, with the coefficient of determination (R²) indicating a strong linear relationship. 2 ) is 0.95 (e.g. Figure 7 (As shown in C and D).
[0046] Experimental Example 5. Pb 2+ Elucidating the mechanism of signal enhancement induced by AuNPs@MBA@HPAM Raman substrate This experimental example systematically analyzes Pb using density functional theory (DFT) calculations, SEM, and particle size analysis. 2+ The intrinsic mechanism of SERDS signal enhancement induced by AuNPs@MBA@HPAM Raman substrates was investigated; further, the capture rate was calculated, and the formula for the capture rate is as follows: ; Comparison of AuNPs@MBA@HPAM Raman substrates with AuNPs and AuNPs@MBA on Pb 2+ Its capture capability.
[0047] like Figure 8 As shown, the AuNPs@MBA@HPAM Raman substrate and Pb² were calculated using DFT. + The chemical enhancement mechanism of the AuNPs@MBA@HPAM Raman substrate was elucidated by analyzing the frontier molecular orbital energy levels and global reactivity parameters before and after coordination. AuNPs@MBA@HPAM Raman substrate and Pb 2+ DFT optimization of molecular structure before and after coordination, such as Figure 8 As shown in A and C; molecular electrostatic potential (MESP) analysis indicates that Pb 2+ After coordination, the system undergoes a significant charge redistribution, such as... Figure 8 As shown in B and D; as Figure 8 As shown in E, the leading molecular orbital energy levels and global reactivity parameters of the system are significantly altered after coordination. These results collectively confirm that Pb² + Coordination-triggered intramolecular charge transfer (ICT) from electron-rich functional groups to the metal center enhances molecular polarizability, thereby achieving SERDS chemical enhancement. The results, combined with SEM and particle size characterization, are shown below. Figure 8 F to Figure 8 As shown in Figure I, Pb² is introduced. + Subsequently, the nanoparticles transform from a relatively dispersed state to a densely aggregated state, generating electromagnetic "hot spots" at the nanoparticle boundaries, thereby synergistically enhancing surface-enhanced Raman scattering. Pb² + Capture efficiency evaluation, such as Figure 8 As shown in J, AuNPs@MBA@HPAM is related to Pb² +The capture efficiency was the highest (approximately 72%), which was 2.7 times that of AuNPs (approximately 27%) and 2.3 times that of AuNPs@MBA (approximately 31%), demonstrating excellent Pb² capture efficiency. + Targeted capture capability.
[0048] Experimental Example 6. Practical Applicability Evaluation of AuNPs@MBA@HPAM Dual-Mode Detection To evaluate the practical utility of the AuNPs@MBA@HPAM Raman substrate, this invention selected drinking water and plasma as actual complex matrix samples and conducted spiked recovery detection verification.
[0049] The results are as follows Figure 9 As shown, the SERDS and UV-vis dual-mode detection method on AuNPs@MBA@HPAM Raman substrates exhibits signal intensity variation with Pb² in two types of real samples. + A favorable response pattern that gradually increases with increasing concentration. In drinking water substrates (such as...) Figure 9 As shown in A, B, and C), SERDS recoveries ranged from 94.30% to 102.46%, and UV-vis recoveries ranged from 97.87% to 102.48%. The relative standard deviations (RSDs) for all results were less than 4%. In plasma matrices (such as...), Figure 9 As shown in D, E, and F), in plasma samples, the recovery rates of SERDS were 99.94%–107.85%, and the recovery rates of UV-vis were 92.00%–104.94%, with corresponding RSD values of less than 3%.
[0050] The above results confirm that the dual-mode sensing platform has high accuracy and good stability in actual samples such as drinking water and blood plasma, and has excellent potential for practical application.
[0051] In summary, the preparation method of this invention is simple and reproducible, integrates differential Raman spectroscopy to effectively subtract fluorescence background, and has a "dual-mode" detection function, enabling efficient and selective detection of Pb in water and plasma. 2+ It demonstrates good application potential and provides new ideas for heavy metal detection.
[0052] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method for preparing an AuNPs@MBA@HPAM Raman substrate, characterized in that, The preparation method includes the following steps: Preparation steps of gold nanoparticle solution: Synthesis of gold nanoparticle solution; The coating steps for 4-mercaptobenzoic acid are as follows: 4-mercaptobenzoic acid is dissolved in an organic solvent to obtain a 4-mercaptobenzoic acid mother liquor; the 4-mercaptobenzoic acid mother liquor is diluted with pure water to obtain a 4-mercaptobenzoic acid working solution; the 4-mercaptobenzoic acid working solution is added to the gold nanoparticle solution and stirred to obtain an AuNPs@MBA mixture; the AuNPs@MBA mixture is centrifuged to obtain an AuNPs@MBA precipitate. The AuNPs@MBA precipitate was washed and resuspended in pure water to obtain an AuNPs@MBA solution. The coating steps for amino-terminated hyperbranched polyamide are as follows: The amino-terminated hyperbranched polyamide is dissolved in pure water to obtain an amino-terminated hyperbranched polyamide solution. Under stirring conditions, an amino-terminated hyperbranched polyamide solution was added to AuNPs@MBA solution and then incubated to obtain the incubation product. The incubation product was centrifuged to obtain AuNPs@MBA@HPAM precipitate; the AuNPs@MBA@HPAM precipitate was resuspended in pure water to obtain AuNPs@MBA@HPAM Raman substrate.
2. The preparation method according to claim 1, characterized in that, In the preparation steps of the gold nanoparticle solution, gold nanoparticle solution is synthesized by sodium citrate reduction method; the synthesis of gold nanoparticle solution by sodium citrate reduction method includes: dissolving trisodium citrate in pure water to obtain trisodium citrate solution; heating the trisodium citrate solution to boiling, then adding chloroauric acid to the boiling trisodium citrate solution to obtain a reaction system; continuously heating the reaction system to boiling until the reaction system changes from colorless to wine red, and then continuing the reaction under boiling conditions for 15-30 min to obtain gold nanoparticle solution.
3. The preparation method according to claim 2, characterized in that, In the preparation steps of the nano-gold solution, the final concentration of trisodium citrate in the reaction system is 0.1-0.2 mg / mL, and the final concentration of chloroauric acid is 0.06-0.09 mg / mL.
4. The preparation method according to any one of claims 1-3, characterized in that, In the 4-mercaptobenzoic acid coating step, the volume ratio of the gold nanoparticle solution to the 4-mercaptobenzoic acid solution is 1:0.5-1; the concentration of the 4-mercaptobenzoic acid solution is 1-3 mM.
5. The preparation method according to any one of claims 1-4, characterized in that, In the coating step of 4-mercaptobenzoic acid, the stirring time is 0.5-1.5 h.
6. The preparation method according to any one of claims 1-5, characterized in that, In the coating step of amino-terminated hyperbranched polyamide, the volume ratio of the AuNPs@MBA solution to the amino-terminated hyperbranched polyamide solution is 1:1-5; the concentration of the amino-terminated hyperbranched polyamide solution is 5-10 mg / mL.
7. The preparation method according to any one of claims 1-6, characterized in that, In the coating step of amino-terminated hyperbranched polyamide, the incubation is carried out on a shaker at a speed of 80-90 rpm and a temperature of room temperature; the incubation time is 6-12 h.
8. An AuNPs@MBA@HPAM Raman substrate, characterized in that, The AuNPs@MBA@HPAM Raman substrate is prepared by the preparation method described in any one of claims 1-7.
9. The AuNPs@MBA@HPAM Raman substrate prepared by the preparation method according to any one of claims 1-7, or the AuNPs@MBA@HPAM Raman substrate according to claim 8, is used to detect Pb in the sample. 2+ Applications in concentration; Preferably, the sample comprises water and / or plasma; Preferably, the detection method of the application includes Raman detection and / or ultraviolet absorption spectroscopy detection.
10. A method for detecting Pb 2+ The method is characterized by, The method uses the AuNPs@MBA@HPAM Raman substrate prepared by the preparation method of any one of claims 1 to 7, or the AuNPs@MBA@HPAM Raman substrate of claim 8, to mix with the sample to be tested to obtain a detection system; the detection system is placed on a Raman spectrometer, and Raman spectra are obtained at excitation wavelengths of 784.5 nm and 785.5 nm; the Raman spectrometer automatically normalizes, reconstructs, subtracts, and corrects the baseline of the obtained Raman spectra to obtain differential Raman spectra; the presence of Pb in the sample to be tested is determined based on the changes in the intensity of the differential Raman spectral signal. 2+ ; Preferably, the determination method is based on comparing the presence of Pb with the blank control group. 2+ The intensity of the differential Raman spectral signal produced by the sample will be enhanced.