CN111830004A - A method of detecting Raman signals - Google Patents

Abstract

The invention relates to the technical field of laser Raman detection, in particular to a method for detecting Raman signals, which comprises the following steps: dripping the mixed solution on a chip to be detected, wherein metal nano particles or metal nano wires are deposited on a substrate of the chip to be detected, and the mixed solution is specifically an electrolyte solution containing molecules to be detected; placing the chip to be detected dropwise with the mixed solution on a lower electrode plate between an upper electrode plate and a lower electrode plate, and applying voltage to the upper electrode plate and the lower electrode plate; the chip to be detected is detected through the Raman detector, the Raman signal of the chip to be detected is obtained, molecules in an acidic or alkaline solution in the dropwise added mixed solution are ionized under the action of an electrolyte solution to carry charges, and under the action of an electric field, the molecules can move along the opposite direction of an electric field line or an electric field line, so that a large number of molecules to be detected are closer to the chip to be detected, the number of the molecules is larger, the Raman signal is stronger, and the Raman detector can detect the enhanced Raman signal.

Description

A method of detecting Raman signals

technical field

The invention relates to the technical field of laser Raman detection, in particular to a method for detecting Raman signals

Background technique

Surface-enhanced Raman scattering (SERS) is to amplify the inherently weak Raman signal by preparing plasmonic nanostructures. Usually, Raman spectroscopy can be used to identify material components. However, due to many chemical substances The signal cannot be detected directly by Raman spectroscopy. Raman enhancement technology is needed to improve the signal-to-noise ratio of the Raman signal, so as to detect the Raman signal of the substance to be detected.

Surface-enhanced Raman scattering technology has become one of the most promising analytical methods due to its extremely high sensitivity, unique fingerprint spectrum, and non-destructive data collection. At present, surface-enhanced Raman scattering technology can enhance Raman signals by preparing various substrate structures, but the preparation of highly sensitive substrate structures is complicated, with poor uniformity, high cost, and difficulty in mass production.

Therefore, how to enhance the Raman signal by a simple method is a technical problem that needs to be solved urgently.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, the present invention is proposed to provide a method of detecting Raman signals that overcomes the above-mentioned problems or at least partially solves the above-mentioned problems.

An embodiment of the present invention provides a method for detecting a Raman signal, including:

dropping the mixed solution on the chip to be detected, the substrate of the chip to be detected is deposited with metal nanoparticles or metal nanowires, and the mixed solution is specifically an electrolyte solution containing the molecule to be detected;

placing the chip to be detected dropwise with the mixed solution on the lower electrode plate between the upper and lower electrode plates, and applying a voltage to the upper and lower electrode plates;

The chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

Further, the detection of the chip to be detected by a Raman detector to obtain the Raman signal of the chip to be detected specifically includes:

After the voltage is applied to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

Further, the detection of the chip to be detected by a Raman detector to obtain the Raman signal of the chip to be detected specifically includes:

In the process of applying voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

Further, the substrate specifically adopts any one of the following materials:

Silicon, silica, black silicon, porous alumina templates, titanium dioxide, graphene, non-woven fabrics, polymethyl methacrylate and tape.

Further, the metal nanoparticles are specifically single metal nanoparticles and/or alloy nanoparticles:

The single metal nanoparticle is specifically gold nanoparticle, silver nanoparticle, or copper nanoparticle;

The alloy nanoparticles comprise at least two metals in gold, silver and copper;

The metal nanowires are specifically gold nanowires, copper nanowires, or silver nanowires.

Further, the shape of the metal nanoparticles is specifically any one of the following:

Star, hexagon and circle.

Further, the molecule to be tested is specifically a molecule of any of the following substances:

R6G, Malachite Green and Methylene Blue.

Further, the electrolyte solution is specifically any one of the following:

Dilute hydrochloric acid, dilute sulfuric acid, dilute phosphoric acid and sodium chloride.

Further, the voltage range applied when the voltage is applied to the upper and lower electrode plates is between 1V and 3V, and the duration of the voltage application is between 10min and 30min.

Further, the upper and lower electrode plates are specifically made of any of the following materials:

Copper, iron, aluminum and titanium oxide.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

A method for detecting Raman signals provided by the present invention adopts a mixed solution dropwise on a chip to be detected, metal nanoparticles or metal nanowires are deposited on the substrate of the chip to be detected, and the mixed solution contains molecules to be detected Electrolyte solution, and then place the chip to be detected with the mixed solution added dropwise on the lower electrode plate between the upper and lower electrode plates, apply a voltage to the upper and lower electrode plates, and detect the chip to be detected by a Raman detector to obtain a to-be-detected chip The Raman signal of the chip adopts the above-mentioned detection method to apply a voltage on the upper and lower electrode plates to generate an electric field, so that the molecule to be tested is ionized and charged under the action of the electrolyte solution. Under the action of the electric field of the upper and lower electrode plates, the molecule It can move along the electric field line or in the opposite direction of the electric field line, so that a large number of molecules gather on the chip to be detected, because the distance between the molecule to be detected and the chip to be detected is reduced by the action of the electric field, and, in the preset of the chip to be detected A large number of molecules to be tested are gathered in the distance range, and the Raman signal is enhanced through the physical enhancement mechanism. The metal nanoparticles on the bottom form bonds or undergo charge transfer, and the Raman signal is enhanced through a chemical enhancement mechanism, so that the Raman detector can detect the enhanced Raman signal of the chip to be detected.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the invention. Also, the same components are represented by the same reference figures throughout the drawings. In the attached image:

1 shows a schematic flowchart of steps of a method for detecting a Raman signal in Embodiment 1 of the present invention;

FIG. 2 shows a schematic structural diagram of a device used for detecting Raman signals in Embodiment 1 of the present invention;

3 shows a schematic flowchart of steps of a method for detecting a Raman signal in Embodiment 2 of the present invention;

FIG. 4 shows a schematic structural diagram of an apparatus used for detecting Raman signals in Embodiment 2 of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be more thoroughly understood, and will fully convey the scope of the present disclosure to those skilled in the art.

The Raman scattering effect is a very weak process. Generally, the light intensity is only about 10 ^-10 of the incident light intensity. Therefore, the Raman signal is very weak and cannot be directly detected by a Raman detector.

An embodiment of the present invention provides a method for detecting a Raman signal, comprising: dropping a mixed solution on a chip to be detected, metal nanoparticles or metal nanowires are deposited on the substrate of the chip to be detected, and the mixed solution specifically contains The electrolyte solution of the molecule to be tested; the chip to be tested with the mixed solution added dropwise is placed on the lower electrode plate between the upper and lower electrode plates, and a voltage is applied to the upper and lower electrode plates; the chip to be detected is detected by a Raman detector to obtain Raman signal of the chip to be detected.

The method for detecting Raman signals includes two implementations. One is to detect the chip to be detected by a Raman detector to obtain the Raman signal of the chip to be detected, which specifically includes:

After applying voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

The other is to detect the chip to be detected by a Raman detector to obtain the Raman signal of the chip to be detected, which specifically includes:

In the process of applying voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

Specifically, the following examples are used to describe in detail.

Example 1

Embodiment 1 of the present invention provides a method for detecting Raman signals, as shown in FIG. 1 , including: S101 , dropping a mixed solution on a chip to be detected, and metal nanoparticles are deposited on the substrate of the chip to be detected Or metal nanowires, the mixed solution is specifically an electrolyte solution containing the molecule to be tested; S102, the chip to be tested on which the mixed solution is added dropwise is placed on the lower electrode plate between the upper and lower electrode plates, and a voltage is applied to the upper and lower electrode plates; S103, after applying a voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

In an optional implementation manner, metal nanoparticles or metal rice wires are deposited on the substrate of the chip to be detected.

Wherein, the substrate specifically adopts any one of the following materials: silicon, silicon dioxide, black silicon, porous alumina template, titanium dioxide, graphene, non-woven fabric, polymethyl methacrylate and adhesive tape. The embodiments of the present invention are not limited to the above-mentioned materials.

The metal nanoparticles are specifically single metal nanoparticles and/or alloy nanoparticles. Wherein, the single metal nanoparticle is specifically gold nanoparticle, silver nanoparticle, or copper nanoparticle; the alloy nanoparticle includes at least two metals among gold, silver, and copper. The alloy nanoparticles specifically include alloy nanoparticles of gold and silver, alloy nanoparticles of gold and copper, alloy nanoparticles of silver and copper, and alloy nanoparticles of gold, silver and copper.

For example, gold nanoparticles, or alloy nanoparticles of gold and copper, or alloy nanoparticles of both gold and copper can be deposited on the substrate.

In addition, the metal nanowire is specifically any one of gold nanowires, silver nanowires, and copper nanowires. Therefore, any one of gold nanowires, silver nanowires, and copper nanowires can also be deposited on the substrate.

The shape of the metal nanoparticle is specifically any one of the following: a star shape, a flower shape, a hexagon and a circle. Among them, the star shape can be a pentagram, a hexagram, and so on. Specifically, the flower pattern can be a shape with uniform edges and corners.

In an optional embodiment, the molecule to be detected is specifically a molecule of any one of the following substances: R6G, malachite green and methylene blue. R6G is preferred, and the R6G can be adjusted into a solution, wherein the concentration of the solution is 10 ^-5 M, and the concentration is not specifically limited.

In the embodiment of the present invention, the electrolyte solution is any one of the following: dilute hydrochloric acid, dilute sulfuric acid, and sodium chloride in dilute phosphoric acid. Preferred is dilute hydrochloric acid.

In S101, after the mixed solution is dropped on the chip to be detected, S102 is performed, and the chip to be detected with the mixed solution added dropwise is placed on the lower electrode plate between the upper and lower electrode plates, and a voltage is applied to the upper and lower electrode plates. As shown in FIG. 2 , a schematic diagram of applying a voltage to the upper and lower electrode plates L1 and L2 through a power supply is to place the chip A to be detected with the mixed solution added dropwise between the upper and lower electrode plates L1 and L2.

Specifically, the upper and lower electrode plates are made of conductive materials such as copper, aluminum, iron or titanium oxide. Copper is preferably used.

In the mixed solution dripped on the chip to be tested, the molecules to be tested are ionized and charged under the action of the electrolyte solution. Under the action of the electric field of the upper and lower electrode plates, the molecules can move along the electric field lines or in the opposite direction of the electric field lines. Because of the action of the electric field, the distance between the molecules to be tested and the chip to be detected is reduced, and a large number of molecules to be tested are gathered within the preset distance range of the chip to be detected. , through the physical enhancement mechanism, the Raman signal is enhanced. At the same time, due to the smaller distance between the molecule to be detected and the chip to be detected under the action of the electric field, the molecule to be detected forms a bond with the metal nanoparticles on the substrate of the chip to be detected. Charge transfer, through a chemical enhancement mechanism, enhances the Raman signal.

Therefore, in the process of S103, after the voltage is applied to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected. That is, after applying a voltage for a preset duration, a Raman detector can detect and obtain an enhanced Raman signal of the chip to be detected.

In an optional embodiment, the voltage range applied to the upper and lower electrode plates is between 1V and 3V, specifically 1V, 2V, and 3V, and the duration of the applied voltage is between 10min and 30min, specifically 10min. , 20min, 30min. Preferably, after applying a voltage of 3V to the upper and lower electrode plates, and applying the voltage for 30 minutes, after applying the voltage for 30 minutes, it also includes taking out the chip to be detected from between the upper and lower electrode plates and drying it. The method can be natural air drying or nitrogen drying, and then the chip to be detected is detected by the Raman detector to obtain an enhanced Raman signal.

When the Raman detector detects the Raman signal, a laser with an incident wavelength of 532 nm is used to irradiate the surface of the chip to be detected, and the scattered Raman spectrum is detected, thereby obtaining an enhanced Raman signal.

Embodiment 2

An embodiment of the present invention also provides a method for detecting a Raman signal, as shown in FIG. 3 , including:

S301, drop a mixed solution on the chip to be detected, where metal nanoparticles or metal nanowires are deposited on the substrate of the chip to be detected, and the mixed solution is specifically an electrolyte solution containing molecules to be detected

S302, placing the chip to be detected with the mixed solution dripped on the lower electrode plate between the upper and lower electrode plates, and applying a voltage to the upper and lower electrode plates;

S303 , in the process of applying the voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected.

The method uses a Raman detector for real-time online detection while applying a voltage. Therefore, the upper electrode plate of the upper and lower electrode plates is provided with a light-transmitting area, so that the laser light emitted by the laser emitting end can pass through the light-transmitting area to reach the chip to be detected, and at the same time, the scattered light of the chip to be detected can pass through the The light-transmitting area reaches the receiver to realize the detection of the chip to be detected by the Raman detector, thereby obtaining an enhanced Raman signal.

Wherein, the light-transmitting area set on the upper electrode plate is specifically provided with openings on the upper electrode plate or the upper electrode plate is directly made of a light-transmitting conductive material. At this time, the upper and lower electrode plates are specifically made of copper, aluminum, iron, oxide Titanium and other conductive materials, preferably titanium oxide, the entire upper plate can be made of transparent titanium oxide material, and the upper plate can also be made of copper, aluminum, iron and other conductive materials, and the upper plate is provided with openings. A transparent conductive plate, such as titanium oxide (TiO ₂ ), is used for the opening. As shown in FIG. 4 , in order to set an opening on the upper electrode plate L1, a transparent conductive plate is used at the opening, and the chip A to be detected is placed on the lower electrode plate L2 between the upper and lower electrode plates L1 and L2. Schematic.

In an optional implementation manner, the substrate of the to-be-detected chip specifically adopts any one of the following materials:

Silicon, silica, black silicon, porous alumina templates, titanium dioxide, graphene, non-woven fabrics, polymethyl methacrylate and tape.

In an optional embodiment, the metal nanoparticles are specifically single metal nanoparticles and/or alloy nanoparticles:

The single metal nanoparticle is specifically gold nanoparticle, silver nanoparticle, or copper nanoparticle;

The alloy nanoparticles comprise at least two metals in gold, silver and copper;

The metal nanowires are specifically gold nanowires, copper nanowires, or silver nanowires.

In an optional embodiment, the shape of the metal nanoparticles is any one of the following:

Star, hexagon and circle. Patterns can also be used, specifically shapes with even edges and corners.

In an optional embodiment, the molecule to be tested is specifically a molecule of any one of the following substances:

R6G, Malachite Green and Methylene Blue.

In an optional embodiment, the electrolyte solution is any one of the following:

Dilute hydrochloric acid, dilute sulfuric acid, dilute phosphoric acid and sodium chloride.

In an optional implementation manner, the voltage applied to the upper and lower electrode plates ranges from 1V to 3V, and the voltage is applied for a duration of 10min to 30min.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

A method for detecting Raman signals provided by the present invention adopts a mixed solution dropwise on a chip to be detected, metal nanoparticles or metal nanowires are deposited on the substrate of the chip to be detected, and the mixed solution contains molecules to be detected Electrolyte solution, and then place the chip to be detected with the mixed solution added dropwise on the lower electrode plate between the upper and lower electrode plates, apply a voltage to the upper and lower electrode plates, and detect the chip to be detected by a Raman detector to obtain a to-be-detected chip The Raman signal of the chip adopts the above-mentioned detection method to apply a voltage on the upper and lower electrode plates to generate an electric field, so that the molecule to be tested is ionized and charged under the action of the electrolyte solution. Under the action of the electric field of the upper and lower electrode plates, the molecule It can move along the electric field line or in the opposite direction of the electric field line, so that a large number of molecules gather on the chip to be detected, because the distance between the molecule to be detected and the chip to be detected is reduced by the action of the electric field, and, in the preset of the chip to be detected A large number of molecules to be tested are gathered in the distance range, and the Raman signal is enhanced through the physical enhancement mechanism. The metal nanoparticles on the bottom form bonds or undergo charge transfer, and the Raman signal is enhanced through a chemical enhancement mechanism, so that the Raman detector can detect the enhanced Raman signal of the chip to be detected.

Although preferred embodiments of the present invention have been described, additional changes and modifications to these embodiments may occur to those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be construed to include the preferred embodiment and all changes and modifications that fall within the scope of the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (10)

1. a method for detecting Raman signal, is characterized in that, comprises: dropping the mixed solution on the chip to be detected, the substrate of the chip to be detected is deposited with metal nanoparticles or metal nanowires, and the mixed solution is specifically an electrolyte solution containing the molecule to be detected; placing the chip to be detected dropwise with the mixed solution on the lower electrode plate between the upper and lower electrode plates, and applying a voltage to the upper and lower electrode plates; The chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected. 2. The method according to claim 1, wherein the detecting the chip to be detected by a Raman detector to obtain a Raman signal of the chip to be detected specifically comprises: After the voltage is applied to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected. 3. The method according to claim 1, wherein the detecting the chip to be detected by a Raman detector to obtain a Raman signal of the chip to be detected specifically comprises: In the process of applying voltage to the upper and lower electrode plates, the chip to be detected is detected by a Raman detector to obtain a Raman signal of the chip to be detected. 4. The method of claim 1, wherein the substrate specifically adopts any one of the following materials: Silicon, silica, black silicon, porous alumina templates, titanium dioxide, graphene, non-woven fabrics, polymethyl methacrylate and tape. 5. The method of claim 1, wherein the metal nanoparticles are specifically single metal nanoparticles and/or alloy nanoparticles: The single metal nanoparticle is specifically gold nanoparticle, silver nanoparticle, or copper nanoparticle; The alloy nanoparticles comprise at least two metals in gold, silver and copper; The metal nanowires are specifically gold nanowires, copper nanowires, or silver nanowires. 6. The method of claim 1, wherein the shape of the metal nanoparticles is any one of the following: Star, hexagon and circle. 7. The method of claim 1, wherein the molecule to be tested is specifically a molecule of any one of the following substances: R6G, Malachite Green and Methylene Blue. 8. The method of claim 1, wherein the electrolyte solution is any one of the following: Dilute hydrochloric acid, dilute sulfuric acid, dilute phosphoric acid and sodium chloride. 9 . The method according to claim 1 , wherein the voltage applied to the upper and lower electrode plates ranges from 1V to 3V, and the duration of voltage application is from 10min to 30min. 10 . 10. The method of claim 1, wherein the upper and lower electrode plates are made of any one of the following materials: Copper, iron, aluminum and titanium oxide.

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