Interferometric micro-nano fiber sensor for specific detection of copper ions and preparation method thereof

Abstract

The application belongs to the technical field of optical fiber sensors, and particularly relates to a specific copper ion detection interferometric micro-nano fiber sensor and a preparation method thereof. The specific copper ion detection interferometric micro-nano fiber sensor is composed of a micro-nano fiber and a functional layer on the micro-nano fiber. The micro-nano fiber is obtained by tapering a double-clad fiber, and includes a middle uniform waist region, transition regions on both sides of the uniform waist region, and a normal region connected to the outer end of the transition regions. The uniform waist region is wrapped with the functional layer, and the functional layer is a material layer capable of specifically recognizing copper ions. The application combines the micro-nano fiber and the functional material, and combines the advantages of the micro-nano fiber, such as miniaturization, low cost, high sensitivity and immunity to electromagnetic interference, with the advantages of the functional material, such as high specific surface area, specificity and good biocompatibility. The drift amount of the spectrum under the specific chelation of copper ions and the functional material is monitored.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber sensors, and in particular relates to an interference type micro-nano optical fiber sensor for specifically detecting copper ions and a preparation method thereof. Background Art

[0002] Copper is one of the most toxic heavy metal elements in the environment. It is necessary to develop a cheap, stable and environmentally friendly sensor to detect Cu in aqueous solution. 2+ Exceeding the standard concentration has important implications for many fields such as ecology and medical monitoring. Summary of the Invention

[0003] In response to the above problems, the present invention provides an interference-type micro-nano optical fiber sensor for specifically detecting copper ions and a preparation method thereof.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0005] The interferometric micro-nano optical fiber sensor for specifically detecting copper ions consists of a micro-nano optical fiber and a functional layer located on the micro-nano optical fiber. The micro-nano optical fiber is obtained by tapering a double-clad optical fiber, including a uniform waist region in the middle, transition regions on both sides of the uniform waist region, and a normal region connected to the outer ends of the transition regions. The functional layer is wrapped on the uniform waist region, and the functional layer is a material layer that specifically recognizes copper ions.

[0006] Furthermore, the length of the transition zone is 4 mm, the length of the beam waist uniform zone is 12 mm, and the diameter is 12 μm.

[0007] The preparation method of the interferometric micro-nano optical fiber sensor comprises the following steps:

[0008] Step 1: Remove the coating layer of a double-clad optical fiber with a length of 2-3 cm, fix it on an optical fiber fixture, and use a fusion taper method to produce a micro-nano optical fiber;

[0009] Step 2: Modify the functional layer to the uniform waist area of ​​the micro-nano optical fiber.

[0010] Furthermore, the specific steps of using the melt taper method to prepare the micro-nano optical fiber in step 1 are: first, the middle position of the double-clad optical fiber is heated for about 5 seconds by a hydrogen-oxygen or butane flame, and then uniformly taper is performed by a mobile displacement platform to obtain the micro-nano optical fiber.

[0011] Furthermore, the step 2 of modifying the functional layer to the uniform waist region of the micro-nano optical fiber specifically includes the following steps:

[0012] Step 2.1: Weigh 1.1069 g of aminopropyltriethoxysilane and 0.4804 g of 2-imidazolecarboxaldehyde in 5 mL of anhydrous ethanol as solvent and incubate in a water bath at 60°C for 2 h to obtain a homogeneous stock solution;

[0013] In step 2.2, 5 g of polyvinyl alcohol was dissolved in 100 mL of deionized water to obtain a 5% polyvinyl alcohol solution.

[0014] Step 2.3: Mix the homogeneous stock solution prepared in step 2.1 with a 5% aqueous solution of polyvinyl alcohol at a volume ratio of 1:5 in a water bath at 60°C for 2 h. The resulting mixed solution is allowed to react for 12 h before use.

[0015] In step 2.4, the micro-nano optical fiber is immersed in the mixed solution for 5 seconds, the immersed micro-nano optical fiber is taken out, unreacted impurities are rinsed with deionized water, and the micro-nano optical fiber is dried at room temperature for 10 minutes to obtain a micro-nano optical fiber sensor.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention combines micro-nano optical fibers with "functionalized materials," organically combining the advantages of micro-nano optical fibers, such as miniaturization, low cost, high sensitivity, and immunity to electromagnetic interference, with the advantages of functionalized materials, such as high specific surface area, specificity, and good biocompatibility. By monitoring the spectral drift under the specific chelation of copper ions with functionalized materials, this invention provides a new approach for realizing inexpensive, stable, and environmentally friendly copper ion sensors.

[0018] 2. The present invention uses a simple dip-coating method to modify the functionalized material onto the micro-nano optical fiber to construct a stable new sensing interface, which can achieve safe, simple and specific copper ion detection;

[0019] 3. The present invention realizes the detection of copper ions based on an interference-type micro-nano optical fiber sensor, which has the advantages of simple operation, low cost, strong anti-interference ability and accurate wavelength modulation, and can ensure a stable and accurate detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the use of the present invention;

[0021] Figure 2 It is a structural schematic diagram of the present invention;

[0022] Figure 3 The sensor spectrum and wavelength drift diagram in the embodiment of the present invention;

[0023] Figure 4 Graph showing the specificity results of the sensor in an embodiment of the present invention;

[0024] Figure 5 Graph showing the stability of the sensor according to an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of the structure of a 3D printing detection device in an embodiment of the present invention;

[0026] In the figure, broadband light source - 1, micro-nano fiber - 2, functional layer - 3, spectrometer - 4, beam waist uniform zone - 201, transition zone - 202, normal zone - 203. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical scheme of the present application, the present application will be further described below through examples.

[0028] The interference type micro-nano fiber sensor for specifically detecting copper ions is composed of a micro-nano fiber and a functional layer located on the micro-nano fiber, the micro-nano fiber is obtained by tapering a double-clad fiber, including a beam waist uniform zone in the middle, transition zones on both sides of the beam waist uniform zone, and a normal zone connected to the outer end of the transition zone, the beam waist uniform zone is wrapped with a functional layer, and the functional layer is a material layer that specifically recognizes copper ions. The length of the transition zone is 4 mm, and the length of the beam waist uniform zone is 12 mm and the diameter is 12 μm.

[0029] The preparation method of the interference type micro-nano fiber sensor comprises the following steps:

[0030] Step 1, remove the coating layer of a double-clad fiber with a length of 2-3 cm, and then fix it on a fiber clamp, and then use the fusion tapering method to obtain a micro-nano fiber, the specific steps are as follows: first, heat the middle position of the double-clad fiber by hydrogen or butane flame for about 5 s, and then uniformly taper by moving the displacement platform to obtain a micro-nano fiber;

[0031] Step 2, modify the functional layer to the beam waist uniform zone of the micro-nano fiber, which comprises the following steps:

[0032] Step 2.1, weigh 1.1069 g of aminopropyltriethoxysilane and 0.4804 g of 2-imidazole formaldehyde, and dissolve them in 5 mL of anhydrous ethanol as a solvent at 60°C water bath for 2 h to obtain a uniform stock solution;

[0033] Step 2.2, dissolve 5 g of polyvinyl alcohol in 100 mL of deionized water to obtain a 5% polyvinyl alcohol solution;

[0034] Step 2.3, mix the uniform stock solution in step 2.1 with the 5% polyvinyl alcohol aqueous solution in a volume ratio of 1:5 at 60°C water bath for 2 h, and then place the mixed solution for 12 h for full reaction before use;

[0035] Step 2.4, immerse the micro-nano fiber in the mixed solution for 5 s, take out the immersed micro-nano fiber, wash the unreacted impurities with deionized water, and dry at room temperature for 10 min to obtain a micro-nano fiber sensor.

[0036] The use method of the interference type micro-nano fiber sensor,

[0037] The interferometric micro-nano optical fiber sensor was placed in a self-made 3D printed detection device for detection. Figure 6 As shown, the device is provided with a central groove for holding the liquid to be detected and placing the micro-nano optical fiber waist uniform area, with a length of 5 cm, a width of 5 mm, and a depth of 2 mm. End grooves are provided at both ends of the central groove, with a length of 2.5 cm, a width of 2 mm, and a depth of 1 mm.

[0038] Specific implementation method in the present invention:

[0039] Polyvinyl alcohol is a water-soluble polymer material with strong adhesion, good air permeability, non-toxicity, and environmental protection. It can be connected to optical fibers. Aminopropyl triethoxysilane acts as a bridge between polyvinyl alcohol and 2-imidazole formaldehyde. 2-imidazole formaldehyde is modified on the surface of the optical fiber and has a chelating effect with copper ions to achieve specific binding. Its response can be observed by spectrometer. Wavelength drift, Figure 3 The detection limit of the copper ion was 5.755×10 8 mol / L. Figure 4 and Figure 5 are the specificity and stability results of the sensor, respectively, where the nonspecific ion solution is Cd 2+ 、Ni 2+ , Ca 2+ 、Fe 3+ 、Na + 、Al 3+ and Mn 2+ The sensor was immersed in solutions with different concentrations of 1.0, 2.0, 4.0, 6.0, 8.0 and 10×10 7 In a mol / L copper ion solution, spectral data was recorded every 5 minutes for a response time of one hour, which shows that the sensor has good stability.

[0040] The foregoing shows and describes the principal features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein.

[0041] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing an interferometric micro-nano optical fiber sensor for specific detection of copper ions, characterized by: The following steps are involved: Step 1: Remove the coating from a 2-3 cm long double-clad optical fiber, fix it on an optical fiber fixture, and use a fusion taper method to produce a micro-nano optical fiber. The micro-nano optical fiber includes a uniform waist region in the middle, transition regions on both sides of the uniform waist region, and a normal region connected to the outer ends of the transition regions. Step 2: Modify the functional layer to the uniform waist area of ​​the micro-nano optical fiber, specifically: Step 2.1: Weigh 1.1069 g of aminopropyltriethoxysilane and 0.4804 g of 2-imidazolecarboxaldehyde in 5 mL of anhydrous ethanol as solvent and incubate in a water bath at 60°C for 2 h to obtain a homogeneous stock solution; In step 2.2, 5 g of polyvinyl alcohol was dissolved in 100 mL of deionized water to obtain a 5% polyvinyl alcohol solution. Step 2.3: Mix the homogeneous stock solution prepared in step 2.1 with a 5% aqueous solution of polyvinyl alcohol at a volume ratio of 1:5 in a water bath at 60°C for 2 h. The resulting mixed solution is allowed to react for 12 h before use. In step 2.4, the micro-nano optical fiber is immersed in the mixed solution for 5 seconds, the immersed micro-nano optical fiber is taken out, unreacted impurities are rinsed with deionized water, and the micro-nano optical fiber is dried at room temperature for 10 minutes to obtain a micro-nano optical fiber sensor.

2. The method for preparing the interferometric micro-nano optical fiber sensor for specific detection of copper ions according to claim 1, wherein: The specific steps of using the melt taper method to prepare the micro-nano optical fiber in step 1 are: first, heat the middle position of the double-clad optical fiber for about 5 seconds by using a hydrogen-oxygen or butane flame, and then uniformly taper it by moving the displacement platform to obtain the micro-nano optical fiber.

3. An interferometric micro-nano optical fiber sensor for specific detection of copper ions prepared by the preparation method according to claim 1 or 2, characterized in that: The micro-nano optical fiber is composed of a micro-nano optical fiber and a functional layer located on the micro-nano optical fiber. The micro-nano optical fiber is obtained by tapering a double-clad optical fiber, including a uniform waist area in the middle, transition areas on both sides of the uniform waist area, and a normal area connected to the outer end of the transition area. The functional layer is wrapped on the uniform waist area, and the functional layer is a material layer that specifically recognizes copper ions.

4. The interferometric micro-nano optical fiber sensor for specific detection of copper ions according to claim 3, characterized in that: The length of the transition zone is 4 mm, the length of the beam waist uniform zone is 12 mm, and the diameter is 12 μm.

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