Preparation method of nano device for enhancing Raman detection

Abstract

The invention belongs to the technical field of nano sensing devices, and particularly relates to a preparation method of a nano device for enhancing sensing sensitivity. The method comprises the following steps: mixing a plant waste rice husk with a noble metal gold ion solution, heating and stirring for a period of time, centrifuging the mixture, and drying to obtain a noble metal-rice husk precursor; and carrying out microwave reaction on the precursor in an alkaline environment to obtain a target product. When the nano material is used as a Raman active catalytic material, the intensity of a detection signal is remarkably improved. The method is green and sustainable, compared with a common electrodeposition method, the preparation process is more simplified, and the method has higher biosolubility and has huge potential in micromolecule detection application in the biological field.

Description

Technical Field

[0001] The invention belongs to the technical field of nano sensor devices, and in particular relates to a method for preparing a nano device for enhancing Raman detection. Background Art

[0002] Surface enhanced Raman scattering (SERS) is a sensitive molecular detection technique that is widely used due to its high spectral resolution and excellent sensitivity.

[0003] First of all, we need to mention the Raman effect. In 1928, Indian physicist CV Raman discovered that the frequency of light changes after scattering, and this change in frequency depends on the characteristics of the scattering material. Therefore, the types of molecules that make up the material can be identified through Raman scattering. However, the signal obtained through Raman scattering is very weak, and the detection sensitivity is too low, which limits the application of Raman scattering in practical fields.

[0004] After the 1960s, the invention of lasers provided an ideal light source for Raman detection, which greatly promoted the application of Raman spectroscopy technology. In 1974, Fleischman et al. observed the strong Raman scattering signal of a single layer of pyridine molecules adsorbed on the rough silver electrode surface in an electrochemical cell for the first time. This was the first time SERS was discovered. People have found that an important prerequisite for the SERS effect is the roughening of the electrode surface, which is generally believed to be related to the principle that surface plasmon resonance enhances SERS. Precious metals such as gold, silver, copper, and alkali metals can all make good use of the resonance of light with plasma waves when total reflection occurs on the surface of the metal film, so they can produce a good SERS effect. In addition, enhanced Raman signals have been observed on the surfaces of non-metallic materials including transition metals, semiconductors, graphene, and their composite materials. Summary of the invention

[0005] [Technical issues to be solved]

[0006] Although researchers are constantly discovering and preparing Raman-active catalytic materials to improve the sensitivity of Raman analysis, how to make the preparation process simpler, more environmentally friendly, and more biocompatible has always been a worthy goal. In our method, a simple and effective microwave method was used to prepare nanodevices with enhanced Raman sensitivity, and the preparation route was cleverly designed to make the precious metals and nanoparticles composite, achieving the goal of sustainable preparation methods and enhanced detection sensitivity.

[0007] [Technical solution]

[0008] 1. A method for preparing a nanodevice for enhanced Raman detection, characterized in that it comprises the following steps:

[0009] Step 1, weighing a certain amount of chloroauric acid solid and dissolving it in ultrapure water to obtain a chloroauric acid aqueous solution; adding rice husk powder to the solution to mix the solid and liquid;

[0010] Step 2, then heating under magnetic stirring; finally, mixing the rice husk powder and the chloroauric acid solution and placing them in an oven until the rice husk powder is completely dried to obtain a dry rice husk-chloroauric acid precursor.

[0011] Step 3: Place the dried rice husk-chloroauric acid precursor obtained in step 2 into a corundum crucible, add potassium hydroxide aqueous solution into the crucible, and heat the crucible in a microwave oven;

[0012] Step 4: During the heating process, when the solution is dry, continue to add potassium hydroxide aqueous solution and heat, then add potassium hydroxide aqueous solution at fixed intervals and heat until dry. Finally, take out the microwaved solution and centrifuge to remove any unreacted substances. Collect the supernatant to obtain gold-silicon composite nanoparticles in the liquid phase.

[0013] A further technical solution of the present invention is that in step 1, the mass of chloroauric acid is 25 mg, the volume of ultrapure water is 5 mL, the container is a 10 mL glass bottle, and the mass of rice husk powder is 1 g;

[0014] According to a further technical solution of the present invention, in step 2, the temperature of the magnetic stirring is set to 50° C., the magnetic speed is 500 r / min, and the heating stirring time is 2 h;

[0015] A further technical solution of the present invention is that in step 2, the oven temperature is 50° C. and the drying time is 24 hours;

[0016] According to a further technical solution of the present invention, in step 3, the volume of the corundum crucible is 500 mL, the concentration of the potassium hydroxide aqueous solution is 1 mol / L, the volume initially added is 10 mL, the microwave heating power is 560 W, and the operating frequency is 2.45 GHz.

[0017] According to a further technical solution of the present invention, when the solution is dried in step 4, the volume of the potassium hydroxide aqueous solution added each time is 5 mL, the fixed interval time is 10 minutes, and the total process lasts for 1 hour; the centrifugal speed of the centrifuge is 12000 r / min.

[0018] According to a further technical solution of the present invention, the gold-silicon composite nanoparticles (material) in step 4 are the target product obtained by the present invention, which can be dissolved in water under alkaline conditions and are therefore stored in a potassium hydroxide aqueous solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Flow chart for the synthesis of rice husk-chloroauric acid precursor

[0020] Figure 2 Flow chart for the synthesis of gold-silicon composite nanomaterials

[0021] Figure 3 This is the electronic spectrum of gold-silicon composite nanomaterials

[0022] Figure 4 Transmission electron microscope image of gold-silicon composite nanomaterials

[0023] Figure 5 Raman frequency shift diagram of Rhodamine B dye in the presence and absence of gold-silicon composite nanomaterials DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention, but it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present disclosure. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The embodiment of the present invention provides a method for preparing a nanodevice for enhanced Raman detection. Figure 1 and Figure 2 As shown, steps 1, 2 and steps 3, 4 in the technical solution are included respectively, so as to better demonstrate the preparation process. The specific steps have been clearly explained in the [technical solution].

[0026] 50 microliters of the aqueous solution of the gold-silicon composite nanomaterial was taken with a pipette and dropped on a silicon wafer with an area of ​​0.5 cm×0.5 cm. After natural drying for 5 minutes, an electron energy spectrum test (EDS) was performed.

[0027] The morphology and element ratio of the obtained materials are Figure 3 As shown, it can be seen that gold and silicon are successfully composited.

[0028] 10 μl of the gold-silicon composite nanomaterial solution was taken with a pipette and dropped onto a copper mesh with a diameter of 3.05 mm. After natural drying for 5 minutes, a transmission electron microscope test was performed. Figure 4 As shown, particles with a size of 10 nanometers can be seen, proving that the material is a nano-sized composite.

[0029] Take the concentration as 10 -4 mol / L Rhodamine B dye 20 μL was dropped on a glass slide and tested for Raman spectrum after drying; -410 μL of mol / L Rhodamine B dye and 10 μL of the aqueous solution of gold-silicon composite nanoparticles were mixed and dropped onto a glass slide. After drying, the Raman spectrum was tested. The laser wavelength was 532 nm.

[0030] like Figure 5 The black curve represents the Raman signal of only Rhodamine B dye, and the red curve represents the Raman signal of Rhodamine B and gold-silicon composite nanoparticles mixed, 1371 cm -1 The characteristic peak of rhodamine B is at 1371cm -1 The Raman intensity at the two positions is nearly 43% higher than that of the former, proving that gold-silicon composite nanoparticles can effectively improve the intensity of Raman detection.

[0031] The above experimental measurements show that when the gold-silicon composite nanomaterial provided by the present invention is used as a device to enhance Raman detection signals, the experimental verification shows that the gold element composite ratio is about 0.07% detected by electronic energy spectrum, and when the concentration of rhodamine B dye is 10 -4 mol / L, the detection sensitivity can be significantly improved, and the signal intensity can be increased by about 43%.

[0032] In summary, the method we used has the following advantages: 1. Rice husk powder is used as raw material, which makes full use of agricultural waste and is a green and sustainable manufacturing method; 2. Compared with the commonly used electrodeposition method, the preparation process is simpler, and the microwave method is used to obtain a composite of gold and nanoparticles in one step, which is a simple process. 3. When the gold element detection content is only 0.07%, the Raman signal enhancement effect reaches 43%, which is excellent performance.

Claims

1. A method for preparing a nanodevice for enhanced Raman detection, characterized in that: The following steps are involved: Step 1, weighing a certain amount of chloroauric acid solid and dissolving it in ultrapure water to obtain a chloroauric acid aqueous solution; adding rice husk powder to the solution to mix the solid and liquid; Step 2, then heating under magnetic stirring; finally, mixing the rice husk powder and the chloroauric acid solution and placing them in an oven until the rice husk powder is completely dried to obtain a dry rice husk-chloroauric acid precursor. Step 3: Place the dried rice husk-chloroauric acid precursor obtained in step 2 into a corundum crucible, add potassium hydroxide aqueous solution into the crucible, and heat the crucible in a microwave oven; Step 4: During the heating process, when the solution is dry, continue to add potassium hydroxide aqueous solution and heat, then add potassium hydroxide aqueous solution at fixed intervals and heat until dry. Finally, take out the microwaved solution and centrifuge to remove any unreacted substances. Collect the supernatant to obtain gold-silicon composite nanoparticles in the liquid phase.

2. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: In the step 1, the mass of chloroauric acid is 25 mg, the volume of ultrapure water is 5 mL, the container is a 10 mL glass bottle, and the mass of rice husk powder is 1 g.

3. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: In step 2, the temperature of the magnetic stirring is set to 50° C., the magnetic speed is 500 r / min, and the heating stirring time is 2 h.

4. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: In step 2, the oven temperature is 50° C. and the drying time is 24 hours.

5. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: In step 3, the volume of the corundum crucible is 500 mL, the concentration of the potassium hydroxide aqueous solution is 1 mol / L, the volume initially added is 10 mL, the microwave heating power is 560 W, and the operating frequency is 2.45 GHz.

6. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: When the solution is dried in step 4, the volume of the potassium hydroxide aqueous solution added each time is 5 mL, the fixed interval time is 10 minutes, and the total process lasts for 1 hour; the centrifugal speed of the centrifuge is 12000 r / min.

7. The method for preparing a nanodevice for enhanced Raman detection according to claim 1, characterized in that: The gold-silicon composite nanoparticles (material) in step 4 are the target product obtained by the present invention, which can be dissolved in water under alkaline conditions and are therefore stored in a potassium hydroxide aqueous solution.

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