Surface imprinting fluorescence-surface enhanced Raman dual-sensing probe as well as preparation method and application thereof

Abstract

The invention relates to the technical field of nano material preparation and environmental analysis chemical detection, in particular to a surface imprinting fluorescence-surface enhanced Raman dual-sensing probe as well as a preparation method and application thereof. The probe is NH2-MIL-53 (Al) (at) MIPs / AuNPs, the NH2-MIL-53 (Al) (at) MIPs / AuNPs take NH2-MIL-53 (Al) as a core and take MIPs as a shell, a core-shell structure is formed, and AuNPs are subjected to in-situ reduction growth; a template molecule of the MIPs is p-nitrophenol, and a functional monomer of the MIPs is dopamine. Compared with the prior art, the surface imprinting fluorescence-surface enhanced Raman dual-sensing probe prepared by the invention combines two detection technologies to achieve dual signal recognition, has extremely high sensitivity and selectivity, and is suitable for detecting p-nitrophenol in samples with low concentration and complex components.

Description

Technical Field

[0001] The invention relates to the technical field of nano material preparation and environmental analytical chemical detection, and in particular to a surface imprinted fluorescence-surface enhanced Raman dual sensing probe and a preparation method and application thereof. Background Art

[0002] 4-Nitrophenol (4-NP) is a common organic pollutant widely used in pesticides, dyes and pharmaceuticals. It is harmful to the environment and human body, mainly entering the human body through skin absorption, inhalation or ingestion. It has hepatotoxicity, nephrotoxicity and neurotoxicity, and may even cause cancer. Due to its strong toxicity, high environmental stability and difficulty in natural degradation, the detection of 4-nitrophenol is of great significance. Timely and accurate detection of 4-nitrophenol helps to assess the degree of pollution, protect the environment and public health, and prevent its accumulation in water sources and food chains.

[0003] High performance liquid chromatography and mass spectrometry are the main methods for detecting p-nitrophenol residues. Although they can provide high-precision and high-sensitivity results, they are expensive to use, complex sample processing, and require high operating techniques. At the same time, the analysis time is long, which limits their applicability in real-time monitoring and large-scale applications. In order to overcome the above problems, researchers have explored a variety of simple and portable detection methods, such as electrochemical method, colorimetry, fluorescence method, surface enhanced Raman spectroscopy (Surface Enhanced Raman Scattering, SERS), etc. as new means of detecting p-nitrophenol. Among them, fluorescence technology, with its high sensitivity and visible characteristics, can quickly detect the target, and is suitable for real-time monitoring and diversified application needs; while SERS, with its extremely high sensitivity and rapid response characteristics, is particularly suitable for scenarios requiring extremely low concentration detection and complex sample analysis, and has excellent application potential and adaptability. However, traditional fluorescence and SERS detection have shortcomings in selectivity, so how to significantly improve selectivity constitutes an urgent technical bottleneck.

[0004] Molecular Imprinting Polymers (MIPs), as an emerging solid phase extraction technology, have attracted widespread attention due to their ability to highly selectively extract target pollutants from complex matrices. MIPs can effectively separate and enrich target molecules by using their specifically designed pore structure and functional groups, and show potential application value in environmental monitoring and food safety. However, traditional MIPs are limited by incomplete template removal, reduced binding ability, poor site accessibility and low affinity. Surface Molecular Imprinting Polymers (SMIPs) generate imprinted recognition sites through polymerization reaction on the surface of solid carriers, which improves the binding efficiency and desorption rate with target molecules, and overcomes the problems of uneven distribution of recognition sites and slow mass transfer rate in traditional MIPs. Luminescent Metal-Organic Frameworks (LMOFs) have the characteristics of large specific surface area, high porosity and adjustable pore size structure.

[0005] Therefore, how to construct a surface-imprinted fluorescence-surface-enhanced Raman dual-sensing nanoprobe based on LMOFs with high optical performance, high selectivity and high sensitivity has important research significance and application value. Summary of the invention

[0006] The purpose of the present invention is to provide a surface imprinted fluorescence-surface enhanced Raman dual sensing probe and its preparation method and application in order to solve at least one of the above problems, so as to solve the problem that it is impossible to construct a surface imprinted fluorescence-surface enhanced Raman dual sensing nanoprobe based on LMOFs with high optical performance, high selectivity and high sensitivity in the prior art, thereby achieving high sensitivity, high selectivity and rapid responsiveness in the detection of p-nitrophenol.

[0007] LMOFs as carriers of MIPs not only have highly stable and adjustable luminescent emission signals, but also effectively prevent the deformation of the MIPs imprinted cavity. In addition, precious metal particles can be further modified on the surface of LMOFs-based SMIPs as SERS substrates, which can realize fluorescence and SERS dual sensing. The present invention selects NH2-MIL-53(Al) with strong fluorescence emission, high specific surface area and good stability as a fluorescence source and carrier. Dopamine (DA) as a natural functional monomer and p-nitrophenol as a template molecule self-polymerize on the surface of NH2-MIL-53(Al) under alkaline and dissolved oxygen conditions to form a polydopamine imprinted polymer shell (NH2-MIL-53(Al)@MIPs). Subsequently, the phenolic hydroxyl and quinone groups of MIPs are reduced with HAuCl4 to convert Au 3+ Reduction to Au0 , forming gold nanoparticles AuNPs on its surface. Subsequently, the template was ultrasonically eluted with an eluent to obtain a surface imprinted fluorescence-surface enhanced Raman dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs based on NH2-MIL-53(Al). During the fluorescence detection process, as the concentration of p-nitrophenol increased, the probe fluorescence was quenched to a certain extent, and the SERS signal of p-nitrophenol gradually increased. The surface imprinted fluorescence-surface enhanced Raman dual sensing probe combines the triple advantages of the excellent optical properties of NH2-MIL-53(Al), the specific recognition ability of MIPs, and the electromagnetic field enhancement effect of AuNPs, providing an efficient and reliable solution for achieving dual sensing detection with high sensitivity, high selectivity and rapid response.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] One of the technical solutions of the present invention is to provide a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, wherein the probe is NH2-MIL-53(Al)@MIPs / AuNPs, wherein NH2-MIL-53(Al)@MIPs / AuNPs has NH2-MIL-53(Al) as a core and MIPs as a shell to form a core-shell structure, and in-situ reduction growth of AuNPs;

[0010] The template molecule of the MIPs is p-nitrophenol, and the functional monomer is dopamine.

[0011] The second technical solution of the present invention is to provide a method for preparing the surface imprinted fluorescence-surface enhanced Raman dual sensing probe as described above, the method comprising: modifying a layer of MIPs on the surface of NH2-MIL-53(Al), then in situ reducing it on its surface and inside to form AuNPs, removing the template molecules, and obtaining the dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs.

[0012] Furthermore, the preparation method comprises:

[0013] (1) NH2-MIL-53(Al) was dispersed in a buffer solution, and the template molecule p-nitrophenol and the functional monomer dopamine were added and stirred to form an NH2-MIL-53(Al)@MIPs layer, and the excess dopamine monomers and polydopamine particles on the surface of NH2-MIL-53(Al)@MIPs were removed.

[0014] (2) The NH2-MIL-53(Al)@MIPs obtained in step (1) is dispersed in a HAuCl4 solution to react and form AuNPs, and then the template molecule p-nitrophenol is removed to obtain a surface imprinted fluorescence-surface enhanced Raman dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs.

[0015] Furthermore, in step (1), the NH2-MIL-53 (Al) can be prepared by the following method: weigh AlCl3·6H2O and NH2-H2BDC, dissolve them in a mixed solution of ultrapure water and DMF (N,N-dimethylformamide), stir, heat at high temperature to carry out synthesis reaction, wash and dry after the reaction to obtain the NH2-MIL-53 (Al) solid powder.

[0016] Furthermore, the mass of the AlCl3·6H2O is 0.5-2g, and the mass of the NH2-H2BDC is 0.5-2g.

[0017] Furthermore, the mass of the AlCl3·6H2O is preferably 0.724 g, and the mass of the NH2-H2BDC is preferably 0.543 g.

[0018] Furthermore, the volume of the ultrapure water is 5-10 mL, the volume of DMF is 10-40 mL, and the stirring time is 0.5-3 h.

[0019] Furthermore, the volume of the ultrapure water is preferably 7.5 mL, the volume of DMF is preferably 22.5 mL, and the stirring time is preferably 0.5 h.

[0020] Furthermore, the high temperature heating is: transferring the mixed solution to a Teflon hydrothermal synthesis reactor, heating at 120-180° C. for 20-25 h, preferably heating at 150° C. for 24 h.

[0021] Furthermore, the washing is centrifugal washing, the centrifugal speed is 5000-8000r / min, the centrifugal time is 8-20min, preferably centrifugal washing at 7000r / min for 10min; the washing times are 3 times, wherein the first and second washing solutions are DMF solutions, and the third washing solution is ultrapure water.

[0022] Furthermore, the drying is performed in a vacuum drying oven at 60° C. overnight.

[0023] Furthermore, in step (1), the NH2-MIL-53(Al) is a white solid powder.

[0024] Furthermore, in step (1), the buffer solution is a 10 mM Tris-HCl solution with a pH of 8.5.

[0025] Furthermore, in step (1), the p-nitrophenol and dopamine undergo a self-polymerization reaction under alkaline and dissolved oxygen conditions, and self-polymerize on the surface of NH2-MIL-53(Al) to form NH2-MIL-53(Al)@MIPs.

[0026] Furthermore, in step (1), the concentration of NH2-MIL-53(Al) is 1-5 mg / mL, the concentration of p-nitrophenol is 0.5-2 mg / mL, and the concentration of dopamine is 0.2-3 mg / mL.

[0027] Furthermore, in step (1), the concentration of NH2-MIL-53(Al) is preferably 2 mg / mL, the concentration of p-nitrophenol is preferably 0.25 mg / mL, and the concentration of dopamine is preferably 2 mg / mL.

[0028] Furthermore, the stirring time of the stirring reaction is 4-12 hours, preferably 5 hours.

[0029] Furthermore, in step (1), excess dopamine monomers and polydopamine particles on the surface of NH2-MIL-53(Al)@MIPs are removed by centrifugal washing.

[0030] Furthermore, the centrifugal washing has a centrifugal speed of 5000-8000 r / min, a centrifugal time of 8-20 min, preferably a centrifugal speed of 8000 r / min for 10 min, a washing number of 2 times, and a washing liquid of ultrapure water.

[0031] Furthermore, in step (2), AuNPs were formed by in situ reduction of HAuCl4 using the phenolic hydroxyl and quinone groups on the surface of NH2-MIL-53(Al)@MIPs.

[0032] Furthermore, in step (2), the concentration of NH2-MIL-53(Al)@MIPs is 1-5 mg / mL, and the concentration of HAuCl4 solution is 1-3 mM.

[0033] Furthermore, in step (2), the concentration of NH2-MIL-53(Al)@MIPs is preferably 2 mg / mL, and the concentration of HAuCl4 solution is preferably 2 mM.

[0034] Furthermore, in step (2), NH2-MIL-53(Al)@MIPs are dispersed in HAuCl4 solution and allowed to stand to form AuNPs, and the standing time is 12-24 hours, preferably 12 hours.

[0035] Furthermore, in step (2), the template molecules are removed by ultrasonic elution.

[0036] Furthermore, the ultrasonic elution is as follows: the prepared material is placed in an eluent and ultrasonically eluted for 10-20 minutes, preferably 10 minutes; the ultrasonic elution is repeated twice, and the completion of the elution is indicated by the inability to detect the template molecules in the solution after elution by a UV-visible spectrophotometer.

[0037] Furthermore, the eluent is a methanol solution containing 4-7% acetic acid, preferably a methanol solution containing 5% acetic acid.

[0038] The third technical solution of the present invention is to provide an application of the surface imprinted fluorescence-surface enhanced Raman dual sensing probe as described above, wherein the surface imprinted fluorescence-surface enhanced Raman dual sensing probe is used for selective fluorescence-surface enhanced Raman dual functional detection of p-nitrophenol.

[0039] Furthermore, the step of detecting p-nitrophenol by the surface imprinted fluorescence-surface enhanced Raman dual sensing probe comprises:

[0040] (a) Fluorescence detection: p-nitrophenol at different concentrations was mixed with a certain concentration of dual-sensing probe NH2-MIL-53(Al)@MIPs / AuNPs, incubated for 5-10 min, and then detected using a fluorescence spectrophotometer to obtain the fluorescence emission spectrum of the sample to be measured;

[0041] Furthermore, the concentration of the NH2-MIL-53(Al)@MIPs / AuNPs is 0.1-1 mg / mL, the volume is 2 mL, the concentration of p-nitrophenol is 0-12 μM, and the volume ratio of NH2-MIL-53(Al)@MIPs / AuNPs to p-nitrophenol is 1:1.

[0042] Furthermore, the excitation wavelength selected by the fluorescence spectrophotometer is 335 nm, and the slit widths for excitation and emission are both 10 nm.

[0043] (b) SERS detection: The analytes of different concentrations were mixed with a certain concentration of the dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs, incubated for 2-5 min, and then detected in a Raman spectrometer to obtain the Raman spectra of each sample to be measured, followed by SERS analysis;

[0044] The concentration of NH2-MIL-53(Al)@MIPs / AuNPs was 1-8 mg / mL, and the concentration of p-nitrophenol was 1×10 -4 -1×10 -11 M, mixed in a volume ratio of 1:1, 10-20 μL of the mixed solution was dropped onto the surface of the silicon wafer, and SERS detection was performed after air-drying at room temperature.

[0045] The Raman spectrometer uses an excitation wavelength of 785 nm, adjusts the Raman excitation time to 1-5 s, and the laser intensity to 20-30 mW.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. By designing a layer of MIPs between the luminescent metal-organic framework NH2-MIL-53(Al) and the surface-enhanced Raman spectroscopy substrate AuNPs, the fluorescence signal is prevented from being quenched by the noble metal surface-enhanced Raman spectroscopy substrate, so that the probe has the ability of dual signal recognition. MIPs have specific recognition ability and can enhance the selective recognition of target molecules. MIPs use specific recognition sites to enable the probe to efficiently capture and analyze specific molecules and avoid interference caused by nonspecific adsorption. This design greatly improves the sensitivity and accuracy of the sensor, making it more reliable and stable in the detection of complex samples.

[0048] 2. The surface imprinted fluorescence-surface enhanced Raman dual sensing probe prepared by the present invention has significant advantages over single-function fluorescence or surface enhanced Raman spectroscopy probes. It can simultaneously use fluorescence technology and surface enhanced Raman spectroscopy for detection. Fluorescence detection can play a pre-detection role by quickly providing preliminary screening results, while surface enhanced Raman spectroscopy detection greatly improves the detection signal intensity through the surface enhanced Raman scattering effect, realizing high-precision and low detection limit analysis. The combination of the two detection technologies achieves dual signal recognition, extremely high sensitivity and selectivity, and is suitable for the detection of p-nitrophenol in low-concentration and complex samples.

[0049] 3. The luminescent metal organic framework NH2-MIL-53(Al) used has excellent optical properties. As a carrier of MIPs, it not only has a highly stable and adjustable luminescence emission signal, but also effectively prevents the deformation of the MIPs imprinting cavity. The precious metal surface enhanced Raman spectroscopy substrate AuNPs has an electromagnetic field enhancement effect, which can enhance the surface enhanced Raman spectroscopy detection signal.

[0050] 4. The preparation process of the surface imprinted fluorescence-surface enhanced Raman dual sensing probe of the present invention has clear logic, simple steps and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The figure is a schematic diagram of the preparation process of a surface imprinted fluorescence-surface enhanced Raman dual sensing probe in the present invention.

[0052] Figure 2The field emission electron microscopy SEM images of NH2-MIL-53(Al), NH2-MIL-53(Al)@MIPs and NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1, wherein A is the field emission electron microscopy SEM image of NH2-MIL-53(Al), B is the field emission electron microscopy SEM image of NH2-MIL-53(Al)@MIPs, and C is the field emission electron microscopy SEM image of NH2-MIL-53(Al)@MIPs / AuNPs.

[0053] Figure 3 Ultraviolet spectra of NH2-H2BDC, NH2-MIL-53(Al), NH2-MIL-53(Al)@MIPs and NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1.

[0054] Figure 4 These are the absorption spectrum, excitation spectrum and emission spectrum of NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1.

[0055] Figure 5 Schematic diagram of the fluorescence response linear curve and linear regression curve of NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 to different concentrations of 4-NP, wherein A is the fluorescence response linear curve and B is the linear regression curve.

[0056] Figure 6 Schematic diagram of the fluorescence linear regression curve of NH2-MIL-53(Al)@NIPs / AuNPs prepared in Comparative Example 1 to different concentrations of 4-NP.

[0057] Figure 7 Schematic diagram of the SERS response linear curve and linear regression curve of NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 to different concentrations of 4-NP, wherein A is the SERS spectrum and B is the linear regression curve.

[0058] Figure 8 Schematic diagram of the SERS linear regression curve of NH2-MIL-53(Al)@NIPs / AuNPs prepared in Comparative Example 1 to different concentrations of 4-NP. DETAILED DESCRIPTION

[0059] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0060] Unless otherwise specified, the reagents and experimental instruments described in the following examples are conventional reagents and experimental instruments.

[0061] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0062] Example 1

[0063] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe. For the specific process, see Figure 1 , the specific steps are as follows:

[0064] (1) Preparation of Al 3+ The luminescent metal organic framework NH2-MIL-53(Al) with NH2-H2BDC as the central ion and NH2-H2BDC as the ligand:

[0065] Weigh 0.724g AlCl3·6H2O and 0.543g NH2-H2BDC, dissolve in a mixed solution containing 7.5mL ultrapure water and 22.5mL DMF, stir for 30min until completely dissolved and mixed, then transfer the mixed solution to a 50mL Teflon hydrothermal synthesis reactor, heat and react at 150°C for 24 hours, and after naturally cooling to room temperature, centrifuge and wash at a centrifugal speed of 7000r / min for 10min, use DMF for centrifugal washing twice and ultrapure water for washing once, and place the precipitate obtained by washing in a vacuum drying oven at 60°C for overnight, and the obtained product is NH2-MIL-53(Al) solid powder;

[0066] (2) Preparation of surface molecular imprinted polymer NH2-MIL-53(Al)@MIPs with NH2-MIL-53(Al) as carrier:

[0067] Weigh 20 mg of the NH2-MIL-53(Al) prepared in step (1), and evenly disperse it in 10 mL of 10 mM Tris-HCl solution at pH = 8.5 under ultrasonic treatment, add 0.25 mg / mL of p-nitrophenol and 2 mg / mL of functional monomer dopamine, and react by magnetic stirring for 5 h, so that MIPs are modified on the surface of NH2-MIL-53(Al), and wash it by centrifugation at 8000 r / min for 10 min with ultrapure water, wash it twice to remove excess dopamine monomers and polydopamine particles on the surface of NH2-MIL-53(Al)@MIPs, and obtain NH2-MIL-53(Al)@MIPs;

[0068] (3) Preparation of surface imprinted fluorescence-surface enhanced Raman dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs:

[0069] Weigh 20 mg of NH2-MIL-53(Al)@MIPs prepared in step (2), evenly disperse it in 10 mL of 2 mM HAuCl4 solution and let it stand for 12 h. Use the phenolic hydroxyl and quinone groups on the surface of NH2-MIL-53(Al)@MIPs to in situ reduce HAuCl4 on the surface and inside of MIPs to form AuNPs. Use a methanol solution containing 5% acetic acid as an eluent to perform ultrasonic elution for 10 min to remove the template molecules, thereby forming molecular imprinting holes that have specific recognition for the analyte p-nitrophenol, and obtain a surface imprinted fluorescence-surface enhanced Raman dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs.

[0070] The field emission electron microscopy (SEM) images and solid powder photos of NH2-MIL-53(Al), NH2-MIL-53(Al)@MIPs and NH2-MIL-53(Al)@MIPs / AuNPs prepared according to Example 1 are shown in the figure. Figure 2 As shown, the UV spectrum is as follows Figure 3 As shown. Figure 2 It can be seen that Figure 2 Compared with A, Figure 2 In B, the surface of NH2-MIL-53(Al) has been modified with a MIPs layer to obtain NH2-MIL-53(Al)@MIPs. Figure 2 Compared with B, Figure 2 C shows that the surface of NH2-MIL-53(Al)@MIPs has been successfully reduced in situ to obtain AuNPs, forming NH2-MIL-53(Al)@MIPs / AuNPs. Figure 3 It can be seen that compared with NH2-H2BDC, NH2-MIL-53(Al) and NH2-MIL-53(Al)@MIPs both shifted toward the long-wave direction, indicating that NH2-MIL-53(Al) and NH2-MIL-53(Al)@MIPs were successfully prepared. Compared with NH2-MIL-53(Al) and NH2-MIL-53(Al)@MIPs, NH2-MIL-53(Al)@MIPs / AuNPs had an absorption peak at a wavelength of 548nm, indicating that AuNPs existed on NH2-MIL-53(Al)@MIPs / AuNPs.

[0071] Example 2

[0072] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, which is the same as that of embodiment 1 except that in step (2), the concentration of the added functional monomer dopamine is 1 mg / mL.

[0073] Example 3

[0074] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, which is the same as that of embodiment 1 except that in step (2), the concentration of the added functional monomer dopamine is 3 mg / mL.

[0075] Example 4

[0076] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, which is the same as that of Embodiment 1 except that in step (3), the concentration of the HAuCl4 solution is 1 mM.

[0077] Example 5

[0078] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, which is the same as that of embodiment 1 except that in step (3), the concentration of the HAuCl4 solution is 3 mM.

[0079] Comparative Example 1

[0080] This embodiment provides a method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, which is the same as Example 1 except that p-nitrophenol is not added in step (2) to obtain a non-imprinted probe NH2-MIL-53(Al)@MIPs / AuNPs.

[0081] The concentrations of the chemical reagents used in the preparation process of Examples 1-5 and Comparative Examples 1-2 are shown in Table 1:

[0082] Table 1 Concentrations of chemical reagents used in the preparation process of Examples 1-5 and Comparative Examples 1-2

[0083] Functional monomer dopamine Template molecule p-nitrophenol <![CDATA[HAuCl4]]> Example 1 2mg / mL 0.25mg / mL 2mM Example 2 1mg / mL 0.25mg / mL 2mM Example 3 3mg / mL 0.25mg / mL 2mM Example 4 2mg / mL 0.25mg / mL 1mM Example 5 2mg / mL 0.25mg / mL 3mM Comparative Example 1 2mg / mL 0 2mM

[0084] Test Example 1

[0085] This test example provides an application of a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, and the NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 and Comparative Example 1 are used for fluorescence detection of the object to be tested. The specific steps are as follows:

[0086] (1) Preparation of standard solution: A set of standard aqueous solutions of p-nitrophenol (pH = 7) was prepared, including p-nitrophenol solutions of different concentrations (0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 10.0, 12.0 μM) and a blank standard.

[0087] (2) 2 mL of 0.1 mg / mL NH2-MIL-53(Al)@MIPs / AuNPs was added to 2 mL of p-nitrophenol standard solution of different concentrations prepared in step (1), and the mixture was allowed to stand for 10 min to allow the p-nitrophenol molecules to be effectively and specifically bound to the holes of NH2-MIL-53(Al)@MIPs / AuNPs. The fluorescence spectrum of each sample was measured by a fluorescence spectrophotometer, and a standard curve was prepared with the p-nitrophenol solution concentration as the horizontal axis and F0 / F-1 as the vertical axis (F is the emission intensity of the emission peak at 435 nm).

[0088] The settings of the fluorescence measurement experiment are: excitation wavelength 335nm, emission wavelength 435nm, slit width of excitation wavelength and emission wavelength are 10nm, and the absorption spectrum, excitation spectrum and emission spectrum are as follows: Figure 4 shown.

[0089] Figure 5 Schematic diagram of the linear curve and linear regression curve of the fluorescence response of NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 to different concentrations of p-nitrophenol, wherein A is the linear curve of fluorescence response and B is the linear regression curve. Figure 5 As shown, under the excitation of 335nm light, the fluorescent probe exhibits blue fluorescence. As the concentration of p-nitrophenol solution increases, the fluorescence is quenched. It shows a good linear relationship in the range of 0.01-3.0μM and 3.0-12.0μM for p-nitrophenol, and the linear regression equations are:

[0090] F0 / F-1=0.6734[C]+0.0058(R 2 =0.9989)(0.01-3.0μM)

[0091] F0 / F-1=0.4005[C]+0.08391(R 2 =0.9979)(3.0-12.0 μM).

[0092] Figure 6 Schematic diagram of the fluorescence linear regression curve of NH2-MIL-53(Al)@NMIPs / AuNPs prepared in Comparative Example 1 to different concentrations of p-nitrophenol. Comparative Example 1 shows a linear relationship to p-nitrophenol in the range of 0.6-12 μM, but Figure 6 It can be seen that the detection sensitivity of comparative example 1 to p-nitrophenol is not high, and the linear regression equations are:

[0093] F0 / F-1=0.0512[C]+0.0247(R 2 =0.9976)(0.6-12μM)

[0094] contrast Figure 5 and Figure 6 , the imprinting factor (IF=K MIP / K NIP ) are 13.15 (0.01-3.0 μM) and 7.82 (3.0-12.0 μM), respectively. This indicates that the fluorescence / surface-enhanced Raman spectroscopy probe of Example 1 has good selectivity and accuracy in the quantitative fluorescence detection of p-nitrophenol, indicating that the NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 is suitable for the determination of trace p-nitrophenol in water.

[0095] Test Example 2

[0096] This test example provides an application of a surface imprinted fluorescence-surface enhanced Raman dual sensing probe, and the NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 and Comparative Example 1 are subjected to SERS detection of the object to be tested. The specific steps are as follows:

[0097] (1) Preparation of standard solution: Prepare a set of standard aqueous solutions of p-nitrophenol (pH = 7): containing different concentrations (1×10 -11 , 1×10 -10 , 1×10 -9 , 1×10 -8 , 1×10 -7 , 1×10 -6 , 1×10 -5 , 1×10 -4 M) and a blank standard.

[0098] (2) 10 μL of 1 mg / mL NH2-MIL-53(Al)@MIPs / AuNPs was dripped onto the surface of a single crystal silicon wafer and dried to form a detection area with a radius of about 3 mm. Subsequently, 10 μL of p-nitrophenol standard solutions of different concentrations prepared in step (1) were dripped into the detection area to allow the p-nitrophenol molecules to be tested to fully and effectively bind specifically to the holes of NH2-MIL-53(Al)@MIPs / AuNPs. After the droplets evaporated naturally, the SERS spectrum of each sample was measured using a Raman spectrometer, with the p-nitrophenol solution concentration as the horizontal axis and the 870 cm-1 wavelength as the horizontal axis. -1 The Raman intensity at is taken as the ordinate and a standard curve is prepared.

[0099] The settings of the SERS measurement experiment are: excitation wavelength 785nm, excitation time 3s, and excitation intensity 20mW.

[0100] Figure 7Schematic diagram of the SERS response linear curve and linear regression curve of NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 to different concentrations of p-nitrophenol, wherein A is the SERS spectrum and B is the linear regression curve. Figure 7 As shown, p-nitrophenol at 1×10 -11 -1×10 -5 M range, which is 780cm -1 The SERS intensity at shows a good linear relationship, and the linear regression equation is:

[0101] I 870 =784.1[C]+9174(R 2 =0.9959).

[0102] Figure 8 Schematic diagram of the SERS linear regression curve of NH2-MIL-53(Al)@NIPs / AuNPs prepared in Comparative Example 1 to different concentrations of p-nitrophenol. -9 -1×10 -4 M shows a linear relationship, but Figure 8 It can be seen that the detection sensitivity of comparative example 1 to p-nitrophenol is not high, and the linear regression equation is:

[0103] I 870 =129.4[C]+1751(R 2 =0.9949).

[0104] This indicates that the fluorescence / surface enhanced Raman spectroscopy probe of Example 1 has good selectivity and accuracy in quantitative SERS detection of p-nitrophenol, indicating that the NH2-MIL-53(Al)@MIPs / AuNPs prepared in Example 1 is suitable for the determination of trace p-nitrophenol in water.

[0105] Test Example 3

[0106] This test example detects p-nitrophenol in the water of Dianshan Lake in Shanghai. Take a certain amount of sample, use the water sample without p-nitrophenol as blank, add a certain mass concentration of p-nitrophenol standard solution, and perform spike recovery experiment.

[0107] According to the surface imprinted fluorescence-surface enhanced Raman dual sensing probe prepared in Example 1, the p-nitrophenol in the water of Dianshan Lake in Shanghai was detected according to the detection steps mentioned in Test Examples 1 and 2. The detection results are shown in Table 2:

[0108] Table 2 Detection results of p-nitrophenol in the water of Dianshan Lake in Shanghai

[0109]

[0110] As shown in Table 2, the detection recovery rate of a surface imprinted fluorescence-surface enhanced Raman dual sensing probe prepared in Example 1 for p-nitrophenol in Dianshan Lake water is close to 100%, and the RSD value is less than 10%, indicating that the result is reliable. It can be seen that the surface imprinted fluorescence-surface enhanced Raman dual sensing probe of NH2-MIL-53(Al) provided by the present invention has good sensitivity and low detection limit.

[0111] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A surface imprinted fluorescence-surface enhanced Raman dual sensing probe, characterized in that: The probe is NH2-MIL-53(Al)@MIPs / AuNPs, which has NH2-MIL-53(Al)@MIPs / AuNPs with NH2-MIL-53(Al) as the core and MIPs as the shell to form a core-shell structure, and in-situ reduction growth of AuNPs; The template molecule of the MIPs is p-nitrophenol, and the functional monomer is dopamine.

2. A method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe as claimed in claim 1, characterized in that: The method comprises: modifying a layer of MIPs on the surface of NH2-MIL-53(Al), then in-situ reducing the surface and interior of the NH2-MIL-53(Al) to form AuNPs, removing the template molecules, and obtaining the dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs.

3. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 2, characterized in that: The preparation method comprises: (1) NH2-MIL-53(Al) was dispersed in a buffer solution, and the template molecule p-nitrophenol and the functional monomer dopamine were added and stirred to form NH2-MIL-53(Al)@MIPs, and the excess dopamine monomers and polydopamine particles on the surface of NH2-MIL-53(Al)@MIPs were removed; (2) The NH2-MIL-53(Al)@MIPs obtained in step (1) are dispersed in a HAuCl4 solution, and in situ reduced to form AuNPs on the surface and inside of the MIPs. The template molecule p-nitrophenol is then removed to obtain a surface imprinted fluorescence-surface enhanced Raman dual sensing probe NH2-MIL-53(Al)@MIPs / AuNPs.

4. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (1), the p-nitrophenol and dopamine undergo a self-polymerization reaction under alkaline and dissolved oxygen conditions, and self-polymerize on the surface of NH2-MIL-53(Al) to form NH2-MIL-53(Al)@MIPs.

5. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (1), the concentration of NH2-MIL-53(Al) is 1-5 mg / mL, the concentration of p-nitrophenol is 0.5-2 mg / mL, and the concentration of dopamine is 0.2-3 mg / mL.

6. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (1), excess dopamine monomers and polydopamine particles on the surface of NH2-MIL-53(Al)@MIPs are removed by centrifugal washing.

7. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (2), AuNPs were formed by in situ reduction of HAuCl4 using the phenolic hydroxyl and quinone groups on the surface of NH2-MIL-53(Al)@MIPs.

8. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (2), the concentration of NH2-MIL-53(Al)@MIPs is 1-5 mg / mL, and the concentration of HAuCl4 solution is 1-3 mM.

9. The method for preparing a surface imprinted fluorescence-surface enhanced Raman dual sensing probe according to claim 3, characterized in that: In step (2), the template molecules are removed by ultrasonic elution.

10. An application of the surface imprinted fluorescence-surface enhanced Raman dual sensing probe as claimed in claim 1, characterized in that: The surface imprinted fluorescence-surface enhanced Raman dual sensing probe is used for selective fluorescence-surface enhanced Raman dual functional detection of p-nitrophenol.

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