阅读说明：本技术 一种AuNP/UiO-68复合材料及其制备方法和应用 (AuNP/UiO-68 composite material and preparation method and application thereof ) 是由 李原婷 吴舟雅 张蒙蒙 韩生 李学剑 杨圆圆 黄燕山 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种AuNP/UiO-68复合材料及其制备方法和应用,制备时先通过恒电压法进行电沉积得到UiO-68材料；将制得的UiO-68材料与四氯金酸溶液混合后,再用硼氢化钠还原制得AuNP/UiO-68复合材料。与现有技术相比,本发明具有工艺简单,条件温和,成本低廉等优点；所制备的AuNP/UiO-68复合材料作为SERS基底显示了优异的性能,可以实现食品中添加剂的高选择性和高灵敏检测,该检测方法无需样品前处理、绿色环保而表现出广阔的应用前景。(The invention relates to an AuNP/UiO-68 composite material and a preparation method and application thereof, wherein in the preparation process, electrodeposition is carried out by a constant voltage method to obtain a UiO-68 material; and mixing the prepared UiO-68 material with a tetrachloroauric acid solution, and reducing by using sodium borohydride to prepare the AuNP/UiO-68 composite material. Compared with the prior art, the method has the advantages of simple process, mild conditions, low cost and the like; the prepared AuNP/UiO-68 composite material has excellent performance as an SERS substrate, can realize high-selectivity and high-sensitivity detection of additives in food, and has wide application prospect without sample pretreatment and environmental protection.)

1. A preparation method of an AuNP/UiO-68 composite material is characterized in that the UiO-68 material is mixed with tetrachloroauric acid, and then sodium borohydride solution is added to reduce the mixture to obtain a target product.

2. The method for preparing AuNP/UiO-68 composite material according to claim 1, wherein the UiO-68 material is generated by electrodeposition, which comprises the following steps:

(1) putting zirconium tetrachloride and terphthalic acid into a container, adding tetrabutylammonium bromide and DMF, performing ultrasonic complete dissolution, then continuously adding a mixed solution of ethanol and acetic acid, and uniformly mixing to obtain a precursor solution;

(2) taking precursor solution as electrolyte, platinum wire as anode and aluminum sheet as cathode, regulating voltage, reacting, washing, separating and drying the white precipitate obtained by deposition to obtain the UiO-68 material.

3. The method for preparing AuNP/UiO-68 composite material according to claim 2, wherein the ratio of the addition amount of zirconium tetrachloride, terphthalic acid, tetrabutylammonium bromide, DMF, ethanol and acetic acid in the precursor solution of step (1) is 0.233 g: 0.242 g: 0.4 g: 20mL of: 10mL of: 5 mL.

4. The method for preparing the AuNP/UiO-68 composite material according to claim 2, wherein in the step (2), the reaction temperature is 50 ℃, the reaction time is 2h, and the reaction voltage is 5-10V.

5. The method for preparing AuNP/UiO-68 composite material according to claim 1, wherein the process of the preparation method is specifically as follows:

dispersing the UiO-68 material in a mixed solution of alcohol and water, adding a tetrachloroauric acid solution, performing ultrasonic dissolution, stirring in the dark, continuously dropwise adding a sodium borohydride solution, continuously stirring, centrifuging, washing and drying to obtain a target product.

6. The method for preparing AuNP/UiO-68 composite material according to claim 5, wherein the ratio of the addition amount of the UiO-68 material, the tetrachloroauric acid solution and the sodium borohydride solution is 10 mg: (1-3) mL: (0.3-0.7) mL.

7. The method for preparing AuNP/UiO-68 composite material according to claim 5 or 6, wherein the volume ratio of alcohol to water is 1:1, the concentration of tetrachloroauric acid solution is 20mM, and the concentration of sodium borohydride solution is 0.05M.

8. The method of claim 5, wherein the stirring time in the dark is 5 hours and the stirring time is 30 min.

9. An AuNP/UiO-68 composite material, characterized in that it is prepared by the preparation method as claimed in any one of claims 1 to 8.

10. The use of an AuNP/UiO-68 composite material as claimed in claim 9 in selective SERS detection of food additives.

Technical Field

The invention belongs to the technical field of electrochemical synthesis, and relates to an AuNP/UiO-68 composite material, and a preparation method and application thereof.

Background

With the wide application of artificially synthesized pigments in the food industry, food safety incidents caused by illegal addition of pigments are becoming more frequent. In order to prevent the pigment from being abused or illegally added in the food production process and protect the health and safety of consumers, the development of a technology for accurately, sensitively and quickly detecting the pigment in the food is particularly important in the modern food safety detection research.

Surface Enhanced Raman Scattering (SERS) is an ultra-sensitive vibrational spectroscopy technique and a general analytical technique. It is a combination of raman spectroscopy and nanotechnology. Raman spectroscopy gives a fingerprint spectrum of a molecule, but is not widely used due to the inherently weak raman signal. The introduction of the noble metal substrate greatly enhances the Raman signal to be more than 10⁴–10¹⁰This facilitates target characterization and detection. The performance of SERS depends to a large extent on the SERS substrate, and it is therefore of great importance to develop an effective SERS substrate for practical use.

MOFs are crystalline porous solid materials formed by coordination bonds between organic linkers and metal ions or clusters. In recent years, metal organic framework Materials (MOFs) and composites of MOF and SERS active metal substrates have received increasing attention. As these substrates have additional advantages over conventional SERS substrates in terms of stability, target concentration and selectivity. Therefore, the method for preparing the SERS sensor has the advantages that the operation is simple, and the in-situ rapid high-sensitivity detection of pollutants is realized by selecting a proper SERS substrate and a preparation method, so that the method has important research significance and application value.

Disclosure of Invention

The invention aims to provide an AuNP/UiO-68 composite material, a preparation method and application thereof, wherein the composite material has excellent performance as an SERS substrate, and can realize high-selectivity and high-sensitivity detection of additives in food.

The purpose of the invention can be realized by the following technical scheme:

one of the technical schemes of the invention provides a preparation method of an AuNP/UiO-68 composite material, which comprises the steps of mixing a UiO-68 material with tetrachloroauric acid, and then adding a sodium borohydride solution for reduction to obtain a target product.

Further, the UiO-68 material is generated by an electrodeposition method, and the specific process comprises the following steps:

(1) putting zirconium tetrachloride and terphthalic acid into a container, adding tetrabutylammonium bromide and DMF, performing ultrasonic complete dissolution, then continuously adding a mixed solution of ethanol and acetic acid, and uniformly mixing to obtain a precursor solution;

(2) taking precursor solution as electrolyte, platinum wire as anode and aluminum sheet as cathode, regulating voltage, reacting, washing, separating and drying the white precipitate obtained by deposition to obtain the UiO-68 material.

Furthermore, in the precursor solution in the step (1), the addition amount ratio of zirconium tetrachloride, terphthalic acid, tetrabutylammonium bromide, DMF, ethanol and acetic acid is 0.233 g: 0.242 g: 0.4 g: 20mL of: 10mL of: 5 mL.

Furthermore, in the step (2), the reaction temperature is 50 ℃, the reaction time is 2 hours, and the voltage is 5-10V.

Further, the preparation method comprises the following specific steps:

the UiO-68 material is firstly dispersed in a mixed solution of alcohol (which can be methanol or ethanol) and water, then a tetrachloroauric acid solution is added, after ultrasonic dissolution, stirring is carried out in the dark, then a sodium borohydride solution is continuously added dropwise, stirring is continuously carried out, and centrifugation, washing and drying are carried out, thus obtaining the target product.

Furthermore, the ratio of the addition amounts of the UiO-68 material, the tetrachloroauric acid and the sodium borohydride is 10 mg: (1-3) mL: (0.3-0.7) mL. More preferably, the volume ratio of the alcohol to the water is 1:1, the concentration of the tetrachloroauric acid solution is 20mM, and the concentration of the sodium borohydride solution is 0.05M.

Furthermore, stirring in the dark was carried out for 5h and stirring was continued for 30 min.

When the reaction voltage and the electrodeposition temperature are low, the synthesized material has no fixed morphology. With the gradual rise of reaction voltage and electrodeposition temperature, the crystal form of the synthetic material becomes better and better, and the particle diameter becomes more uniform. Acetic acid monodentate ligand is added as a regulator in the reaction system to perform coordination competition with the bridging ligand, so that the coordination process is regulated.

The second technical scheme of the invention provides an AuNP/UiO-68 composite material which is prepared by the preparation method as claimed in any one of claims 1 to 8.

The third technical scheme of the invention provides application of the AuNP/UiO-68 composite material in selective SERS detection of food additives.

The selective SERS detection method for the food additive specifically comprises the following steps: mixing the AuNP/UiO-68 composite material with a food additive solution, oscillating and uniformly mixing for 3h at room temperature, directly taking the mixed solution by using a capillary tube, placing the mixed solution under a laser confocal micro-Raman spectrometer for Raman detection, and taking the SERS spectrum average value for each sample for three times of measurement.

Further, the volume ratio of the AuNP/UiO-68 composite material to the food additive solution is 1: 3.

Further, the instrument parameters of raman detection are: the excitation wavelength is 785nm, the Raman integration time is adjusted to 10000ms, and the laser intensity is 20 mW.

Compared with the prior art, the invention has the following advantages:

(1) the UiO-68 material is prepared by an electrodeposition method, and the method can well control the morphology and has short synthesis time.

(2) The composite material is prepared by a sodium borohydride reduction method, so that the composite material is green and environment-friendly and has low cost;

(3) the AuNP/UiO-68 composite material prepared by the method has very good SERS detection performance and has wide application prospect in SERS chemical sensors.

Drawings

FIG. 1 is a preparation diagram of the UiO-68 material obtained in example 1;

FIG. 2 is a diagram of the preparation of AuNP/UiO-68 composite obtained in example 1;

FIG. 3 is an infrared image of the AuNP/UiO-68 composite obtained in example 1;

FIG. 4 shows the adsorption of 1.0X 10 of AuNP/UiO-68 obtained in example 4^-5Raman spectrum of mol/L crystal violet.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the following examples, unless otherwise specified, all the conventional commercially available raw materials or conventional processing techniques in the art are indicated.

Example 1:

the embodiment relates to a preparation method of an AuNP/UiO-68 composite material, and the specific process is shown in figures 1 and 2 and comprises the following steps:

1) synthesis of UiO-68: accurately weighing 0.233g of zirconium tetrachloride and 0.242g of 1,1':4',1 '-terphenyl-4, 4' -dicarboxylic acid, putting the zirconium tetrachloride and the 1,1':4',1 '-terphenyl-4, 4' -dicarboxylic acid into a beaker, adding 0.4g of tetrabutylammonium bromide and 20ml of DMF into the beaker to perform ultrasonic treatment to completely dissolve the tetrabutylammonium bromide and the DMF, then adding 10ml of ethanol and 5ml of acetic acid into the beaker, and uniformly mixing the tetrabutylammonium bromide and the DMF by using ultrasonic treatment to obtain the electrolyte. The beaker was placed in a water bath at 50 ℃. Taking a platinum wire as an anode and an aluminum sheet as a cathode, performing electrodeposition by a constant voltage method at 10V for 2h, washing the obtained white precipitate, centrifuging and drying. The size of the obtained UiO-68 material is 100-150 nm.

2) Preparing an AuNP/UiO-68 composite material: 10mg of UiO-68 powder was weighed into a 25mL beaker, 10mL of a mixed solution of water and methanol (v/v ═ 1:1) was added, and 2mL of 20mM HAuCl was added₄Dissolving the UiO-68 powder in the solution by ultrasonic for 60 s. The beaker is placed in the dark and stirred for 5 hours at room temperature, and then stirred for 1 hour in an ice-water bath at the temperature of 4 ℃. Followed by dropwise addition of 1mL of 0.05M NaBH₄And continuing stirring in the ice-water bath for 0.5h, centrifuging the reaction solution (10000rpm, 10min) and washing for three times, adding 10mL of ultrapure water to dissolve and precipitate to obtain a mauve AuNP/UiO-68 solution, and storing the solution in a refrigerator at 4 ℃ for later use. The size of the obtained AuNPs is 40-50 nm. The obtained infrared image of AuNP/UiO-68 is shown in FIG. 3, wherein 663cm^-1And 767cm^-1Representing longitudinal and transverse oscillations of the Zr-O bond, 1575cm^-1Is the vibration of the C-O-Zr bond. 1657cm^-1Vibration absorption attributable to the carboxyl group C ═ O. 1402cm^-1Is prepared from 1,1', 4', 1'-COO-vibration of the carboxyl group on terphenyl-4, 4 "-dicarboxylic acid. 3419cm^-1Here is due to the-OH absorption peak of UiO-68, indicating that the material contains a large amount of water.

Example 2:

in this example, 0.5mL of 1mg/mL AuNP/UiO-68 composite (prepared in example 1, with the same amount of UiO-68 as a control) was combined with 0.5mL of 10^-5mixing the mol/L crystal violet solution, oscillating and uniformly mixing for 3h at room temperature, directly taking the mixed solution by using a capillary tube, placing the mixed solution under a laser confocal micro-Raman spectrometer for Raman detection, and taking the average value of the SERS spectrum by measuring each sample for three times. The instrument parameters of the raman detection are: the excitation wavelength is 785nm, the Raman integration time is adjusted to 10000ms, and the laser intensity is 20 mW.

As shown in fig. 4, the composite material of the UiO-68 on which the gold nanoparticles are supported can effectively enhance the raman signal.

Example 3:

compared with example 1, most of the components are the same, except that the amount of the tetrachloroauric acid and the sodium borohydride in the example is adjusted so that the ratio of the addition amounts of the UiO-68 material, the tetrachloroauric acid and the sodium borohydride is 10 mg: 1 ml: 0.3 mL.

Example 4:

compared with example 1, most of the components are the same, except that the amount of the tetrachloroauric acid and the sodium borohydride in the example is adjusted so that the ratio of the addition amounts of the UiO-68 material, the tetrachloroauric acid and the sodium borohydride is 10 mg: 3 ml: 0.7 mL.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.