WO2022007442A1

WO2022007442A1 - Lactic acid sensor, preparation method and use

Info

Publication number: WO2022007442A1
Application number: PCT/CN2021/083726
Authority: WO
Inventors: 张俊叶; 袁光良; 李振华; 王吉华; 周耀旗; 王静
Original assignee: 德州学院
Priority date: 2020-07-10
Filing date: 2021-03-30
Publication date: 2022-01-13
Also published as: CN111781152A; LU101987B1; CN111781152B

Abstract

A graphene-sensitized optical fiber lactic acid sensor and a preparation method therefor. The graphene-sensitized optical fiber lactic acid sensor comprises: an optical fiber and a nickel plating layer. The preparation method comprises growing a graphene layer at a polished area after the optical fiber is fused and tapered, and coating the graphene layer with the nickel plating layer. A single mode optical fiber is tapered, graphene is directly grown at an optical fiber polished area by using a chemical deposition method to form a complete uniform graphene layer, so that a nickel sensitive material is stably combined with the optical fiber, thereby manufacturing a novel graphene-based optical fiber lactic acid sensor, and achieving good linearity fitting degree and repeatability in lactic acid measurement at a low concentration.

Description

一种乳酸传感器、制备方法及应用A kind of lactic acid sensor, preparation method and application

技术领域technical field

本发明涉及传感器技术领域，具体涉及一种乳酸传感器、制备方法及应用，特别是涉及一种石墨烯增敏的光纤乳酸传感器及其制备方法。The invention relates to the technical field of sensors, in particular to a lactic acid sensor, a preparation method and application, and in particular to a graphene-sensitized optical fiber lactic acid sensor and a preparation method thereof.

背景技术Background technique

本部分的陈述仅仅是提供了与本发明相关的背景技术信息，不必然构成在先技术。The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

乳酸是每个人体内自然产生的一种机体化合物，它既是运动给人体产生的一种副产品，也是人体进行运动的一种燃料，在许多运动实验室里，血乳酸反应和心率一样已成为一项常规变量，血乳酸水平和乳酸清除率可用于判断恶性肿瘤术后出现感染及感染性休克患者的病情及新生儿败血症预后的生化指标，评估脓毒血症患者预后的临床意义与价值。Lactic acid is a body compound naturally produced in every human body. It is not only a by-product of exercise, but also a kind of fuel for human body to exercise. Conventional variables, blood lactate level and lactate clearance rate can be used to judge the condition of patients with infection and septic shock after malignant tumor surgery, as well as biochemical indicators of the prognosis of neonatal sepsis, and to evaluate the clinical significance and value of the prognosis of patients with sepsis.

NiO是一种具有立方方结构的无机材料，溶于酸和氢氧化铵，不溶于碱，因具有热敏系数高、制备成本低、光学性稳定、电化学性能好、环境相容性好、催化活性高等优点，在电化学、光催化和磁性材料等领域普遍的应用；乳酸与镍具有独一无二的络合系数，可与氧化镍络合形成稳定络合物。NiO is an inorganic material with a cubic structure, soluble in acid and ammonium hydroxide, but insoluble in alkali. It has the advantages of high catalytic activity and is widely used in the fields of electrochemistry, photocatalysis and magnetic materials; lactic acid and nickel have a unique complex coefficient, which can be complexed with nickel oxide to form a stable complex.

石墨烯是碳原子以SP^2杂化轨道组成六角形，呈蜂巢结构排列的单层二维晶体，广义的石墨烯也包括数层原子厚度的碳膜。石墨烯具有超高的电荷迁移率[约10000cm^2/(V·s)]、巨大的比表面积(理论值约为2630m2/g)、极高的热导率[约为5000W/(m·K)]、低的约翰孙噪声及1/f噪声等许多独特的性质；从2007 年开始，科学家们已经发现本征态石墨烯非常容易吸附极性分子，曼彻斯特大学的F.Schedin发现由石墨烯制成的微米量级的传感器能够检测到吸附在其表面或从表面脱附的液体分子，这些分子作为供体或受体会改变石墨烯的本地载流子浓度，并相应的改变电导率等物理参数，通过外加电压检测受外界分子影响后输出电流的变化，可实现超敏的液体传感。Graphene is a single-layer two-dimensional crystal in which carbon atoms form hexagonal SP^2 hybrid orbitals and are arranged in a honeycomb structure. In general, graphene also includes carbon films with several layers of atomic thickness. Graphene has ultra-high charge mobility [about 10000cm^2/(V·s)], huge specific surface area (theoretical value is about 2630m2/g), and extremely high thermal conductivity [about 5000W/(m·s]. K)], low Johnson noise and 1/f noise and many other unique properties; since 2007, scientists have found that eigenstate graphene is very easy to adsorb polar molecules, F. Schedin of the University of Manchester found that graphite Micron-scale sensors made of graphene are able to detect liquid molecules that are adsorbed on or desorbed from its surface, and these molecules act as donors or acceptors to change the graphene's local carrier concentration and correspondingly change the conductivity It can realize ultra-sensitive liquid sensing by detecting the change of output current after being affected by external molecules by applying voltage and other physical parameters.

发明人发现，目前在对乳酸浓度进行检测的传感器中，仅化学镀氧化镍的光纤传感器对不同区间的乳酸浓度的区分度变化不明显，对低浓度的乳酸检测不灵敏，稳定性低，无法完成高精度的乳酸浓度测量。The inventors found that among the sensors currently used to detect lactic acid concentration, the optical fiber sensor with only electroless nickel oxide plating has no obvious change in the degree of discrimination of lactic acid concentration in different intervals, and is insensitive to low-concentration lactic acid detection, and has low stability. Complete high-precision lactate concentration measurement.

发明内容SUMMARY OF THE INVENTION

为了解决上述问题，本发明提出了一种石墨烯增敏的光纤乳酸传感器及其制备方法，对单模光纤进行拉锥，采用化学沉积方法在光纤抛磨区域直接生长石墨烯，形成完整均匀的石墨烯层，使得镍敏感材料与光纤稳定结合，从而制作新型的基于石墨烯的光纤乳酸传感器，对低浓度的乳酸测量具有良好的线性拟合度及可重复性。In order to solve the above problems, the present invention proposes a graphene-sensitized optical fiber lactic acid sensor and a preparation method thereof. The single-mode optical fiber is tapered, and the chemical deposition method is used to directly grow graphene in the optical fiber polishing area to form a complete and uniform optical fiber. The graphene layer enables the stable combination of nickel-sensitive materials and optical fibers, thereby making a new graphene-based optical fiber lactic acid sensor, which has good linear fit and repeatability for low-concentration lactic acid measurement.

为了实现上述目的，本发明采用如下技术方案：In order to achieve the above object, the present invention adopts the following technical solutions:

第一方面，本发明提供一种石墨烯增敏的光纤乳酸传感器，包括：光纤和镍镀层；在所述光纤经熔融拉锥后的抛磨区域处生长石墨烯层，在石墨烯层处涂覆所述镍镀层。In the first aspect, the present invention provides a graphene-sensitized optical fiber lactic acid sensor, comprising: an optical fiber and a nickel coating; a graphene layer is grown at the polishing area after the optical fiber is fused and tapered, and a graphene layer is coated on the graphene layer. overlying the nickel coating.

第二方面，本发明提供一种石墨烯增敏的光纤乳酸传感器的制备方法，包括：In a second aspect, the present invention provides a preparation method of a graphene-sensitized optical fiber lactic acid sensor, comprising:

将光纤进行熔融拉锥后，在抛磨区域处生长石墨烯，并经氧化处理得到氧化石墨烯层；After the optical fiber is melted and tapered, graphene is grown at the polishing area, and a graphene oxide layer is obtained through oxidation treatment;

由硫酸镍溶液与还原剂溶液制备镍镀溶液，将光纤的氧化石墨烯层浸泡在镍镀溶液中。A nickel plating solution is prepared from a nickel sulfate solution and a reducing agent solution, and the graphene oxide layer of the optical fiber is immersed in the nickel plating solution.

第三方面，一种第一方面所述的石墨烯增敏的光纤乳酸传感器在乳酸浓度检测中的应用。In a third aspect, an application of the graphene-sensitized optical fiber lactic acid sensor described in the first aspect in the detection of lactic acid concentration.

与现有技术相比，本发明的有益效果为：Compared with the prior art, the beneficial effects of the present invention are:

本发明基于乳酸与镍的络合反应原理，基于熔融拉锥增强光纤传感器件的倏逝场强度以提高传感特性的原理，对单模光纤进行拉锥，采用化学沉积方法在光纤抛磨区域直接生长石墨烯，形成完整均匀的石墨烯层，使得镍敏感材料与光纤稳定结合，从而制作一种新型的基于石墨烯的光纤乳酸传感器，该传感器对低浓度的乳酸溶液具有良好的线性拟合度及可重复性。The invention is based on the complex reaction principle of lactic acid and nickel, and based on the principle that the evanescent field strength of the optical fiber sensing device is enhanced by melting taper to improve the sensing characteristics, the single-mode optical fiber is tapered, and the chemical deposition method is used in the optical fiber polishing area. Graphene is directly grown to form a complete and uniform graphene layer, so that the nickel-sensitive material can be stably combined with the optical fiber, thereby fabricating a novel graphene-based fiber-optic lactic acid sensor, which has a good linear fit for low-concentration lactic acid solution. degree and repeatability.

本发明的传感器基于石墨烯良好的吸附特性和原子厚度使得乳酸分子均匀并紧密的吸附在敏感镀层内，能够明显区分不同区间的乳酸浓度，对低浓度的乳酸检测灵敏性高，稳定性高，实现高精度的乳酸浓度测量。The sensor of the invention is based on the good adsorption characteristics and atomic thickness of graphene, so that the lactic acid molecules are uniformly and tightly adsorbed in the sensitive coating layer, and the lactic acid concentration in different intervals can be clearly distinguished, and the detection sensitivity and stability of low concentration lactic acid are high. Realize high-accuracy lactate concentration measurement.

附图说明Description of drawings

构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

图1为本发明实施例1提供的锥形光纤示意图；1 is a schematic diagram of a tapered optical fiber provided in Embodiment 1 of the present invention;

图2(a)为本发明实施例1提供的化学镀氧化镍后不同乳酸浓度下光谱仪输出光强变化；Fig. 2 (a) is the variation of spectrometer output light intensity under different lactic acid concentrations after the electroless nickel oxide plating provided by the embodiment of the present invention 1;

图2(b)为本发明实施例1提供的化学镀氧化镍掺杂石墨烯涂覆后不同乳酸浓度下光谱仪的输出光强的变化；Fig. 2 (b) is the variation of the output light intensity of the spectrometer under different lactic acid concentrations after the electroless nickel oxide doped graphene coating provided by the embodiment of the present invention 1;

图3为本发明实施例1提供的空气中折射率传感器的稳定性示意图；3 is a schematic diagram of the stability of the refractive index sensor in air provided in Embodiment 1 of the present invention;

图4为本发明实施例1提供的折射率溶液中传感器的稳定性示意图；4 is a schematic diagram of the stability of the sensor in the refractive index solution provided in Embodiment 1 of the present invention;

图5为本发明实施例1提供的折射率传感器的测量重复性示意图。FIG. 5 is a schematic diagram of measurement repeatability of the refractive index sensor provided in Embodiment 1 of the present invention.

具体实施方式：detailed description:

下面结合附图与实施例对本发明做进一步说明。The present invention will be further described below with reference to the accompanying drawings and embodiments.

应该指出，以下详细说明都是示例性的，旨在对本发明提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图限制根据本发明的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、***、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that the terms "including" and "having" and any conjugations thereof are intended to cover the non-exclusive A process, method, system, product or device comprising, for example, a series of steps or units is not necessarily limited to those steps or units expressly listed, but may include those steps or units not expressly listed or for such processes, methods, Other steps or units inherent in the product or equipment.

在不冲突的情况下，本发明中的实施例及实施例中的特征可以相互组合。Embodiments of the invention and features of the embodiments may be combined with each other without conflict.

实施例1Example 1

本实施例提供一种石墨烯增敏的光纤乳酸传感器，包括：光纤和镍镀层；在所述光纤经熔融拉锥后的抛磨区域处生长石墨烯层，在石墨烯层处处涂覆所述镍镀层。This embodiment provides a graphene-sensitized optical fiber lactic acid sensor, including: an optical fiber and a nickel coating; a graphene layer is grown at the polishing area after the optical fiber is fused and tapered, and the graphene layer is coated with the Nickel plating.

在本实施例中，光纤是光导纤维的简写，是一种由玻璃或塑料制成的纤维，可作为光传导工具，一般由一层折射率比纤芯低的玻璃封套包围着纤芯。In this embodiment, the optical fiber is the abbreviation of optical fiber, which is a kind of fiber made of glass or plastic, which can be used as a light transmission tool. Generally, the fiber core is surrounded by a layer of glass envelope with a lower refractive index than the fiber core.

在本实施例中，光纤的抛磨包括断面抛磨和侧面抛磨，断面抛磨光纤通过研磨裸光纤制作的各种光纤斜面、锥面等；侧边抛磨光纤是在普通通信光纤上，利用光学微加工技术，在一段长度上将圆柱形的光纤包层抛磨掉一部分露出纤芯所制成的光纤；In this embodiment, the polishing of the optical fiber includes section polishing and side polishing. The section polishing optical fiber is made by polishing various optical fiber slopes, tapered surfaces, etc. of the bare optical fiber; the side polishing optical fiber is on a common communication optical fiber, Using optical micromachining technology, the optical fiber made by polishing the cylindrical fiber cladding to expose a part of the fiber core in a length of time;

光纤熔融拉锥是将单根或多根去除外层包层的光纤，按照一定方法排布在火焰二氧化碳激光器或加热电弧等高温作用下拉伸光纤，在加热光纤的部分拉制出双锥体结构。Fiber fusion taper is to draw a single or multiple fibers with the outer cladding removed, and arrange them in a certain method under the action of a high temperature such as a flame carbon dioxide laser or a heating arc, and draw a double cone in the heating fiber. structure.

在本实施例中，对光纤首先进行熔融拉锥，包括：In this embodiment, the optical fiber is first fused and tapered, including:

选取一段光纤，将需要熔拉的区域去掉涂覆层，使用酒精擦拭干净；Select a section of optical fiber, remove the coating layer from the area that needs to be melted and pulled, and wipe it with alcohol;

将光纤通过夹具固定在位移平台上，需要熔拉的部位放置在石墨加热子中心附近；Fix the optical fiber on the displacement platform through the clamp, and place the part that needs to be melted and pulled near the center of the graphite heater;

其次调节加热子及位移平台的位置，使得光纤熔拉部分与加热子中心等高并同轴；Secondly, adjust the position of the heater and the displacement platform, so that the fusion-pulling part of the fiber is at the same height and coaxial with the center of the heater;

最后，根据实验需要，编写程序调控拉锥参数，如时间、速度、功率等，获得所需求的光纤传感器件；Finally, according to the needs of the experiment, write a program to control the parameters of the taper, such as time, speed, power, etc., to obtain the required optical fiber sensing device;

拉锥完成后，通过CCD相机可采集光纤器件的具体形貌尺寸，如图1所示。After the taper is completed, the specific morphology and size of the optical fiber device can be collected by a CCD camera, as shown in Figure 1.

在本实施例中，光纤选取单模光纤；In this embodiment, the optical fiber selects a single-mode optical fiber;

在本实施例中，将单模光纤完成熔融拉锥后，采用化学沉积(CVD)方法在光纤抛磨区域直接生长石墨烯，形成完整均匀的石墨烯层，使得敏感材料与光纤稳定结合；In this embodiment, after the single-mode optical fiber is melted and tapered, the chemical deposition (CVD) method is used to directly grow graphene in the optical fiber polishing area to form a complete and uniform graphene layer, so that the sensitive material is stably combined with the optical fiber;

对石墨烯的制备方法中，主要有微机械剥离法、化学剥离法、还原氧化石墨烯法、外延生长法、电化学剥离法、解压缩碳纳米管法、有机合成法以及化学气相沉积(CVD)法等；其中CVD法是利用过渡金属和一些贵金属在高温下促进甲烷或乙醇分子分解，在冷却基板上，碳在过渡金属中的溶解度降低，同时碳薄膜从表面沉淀，温度和流速对于石墨烯的沉积至关重要，CVD法制备的石墨烯面积大、污染小且易于转移，因此，在本实施例中，优先通过CVD方法制造石墨烯。Among the preparation methods of graphene, there are mainly micromechanical exfoliation, chemical exfoliation, reduced graphene oxide, epitaxial growth, electrochemical exfoliation, decompression of carbon nanotubes, organic synthesis and chemical vapor deposition (CVD). ) method, etc.; in which the CVD method uses transition metals and some noble metals to promote the decomposition of methane or ethanol molecules at high temperatures, on the cooling substrate, the solubility of carbon in transition metals is reduced, and carbon films are precipitated from the surface, temperature and flow rate for graphite The deposition of graphene is very important. The graphene prepared by the CVD method has a large area, little pollution and is easy to transfer. Therefore, in this embodiment, the graphene is preferentially manufactured by the CVD method.

在本实施例中，将生长在光纤上的石墨烯通过Hummers氧化法制成氧化石墨烯，通过制备镀液再将其进行磺化处理和敏化活化处理；In the present embodiment, the graphene grown on the optical fiber is made into graphene oxide by the Hummers oxidation method, and the plating solution is prepared and then subjected to sulfonation treatment and sensitization activation treatment;

镀液配置方法为：22g/L的六水合硫酸镍，35g/L醋酸钠，30g/L柠檬酸钠，25g/L次磷酸钠，适量氨水，溶液调节pH值约10得到化学镀溶液；The plating solution configuration method is: 22g/L nickel sulfate hexahydrate, 35g/L sodium acetate, 30g/L sodium citrate, 25g/L sodium hypophosphite, an appropriate amount of ammonia, and the solution is adjusted to a pH value of about 10 to obtain an electroless plating solution;

将光纤包覆区浸泡在镀液中，室温下超声分散30min，70℃恒温水浴35min,随后取出烧杯，进行离心分离、水洗、醇洗、70℃恒温干燥处理后，得到基于石墨烯的光纤乳酸传感器。Soak the optical fiber coating area in the plating solution, ultrasonically disperse it at room temperature for 30 minutes, and then take out the beaker in a constant temperature water bath at 70 °C for 35 minutes. sensor.

目前的研究中，在一种特殊的大芯径塑料D型光波导的侧剖面生长石墨烯，该传感结构的灵敏度高于传统电子薄膜传感器和基于倏逝波的传统微光子传感器近两个数量级，基于石墨烯—微纳光纤复合结构的化学液体传感器通过微纳光纤与石墨烯的贴附，将倏逝波耦合到石墨烯波导表面，当液体分子与石墨烯接触时，复合波导的模有效折射率被改变，从而引起偏振相关的衰减，通过检测输出光信号的强度变化，获得化学液体浓度的变化，开启了基于石墨烯—光纤波导的液体传感研究，为石墨烯和微纳光纤传感器的有效结合提供了强有力的支撑。In the current study, graphene is grown on the side profile of a special large-core plastic D-type optical waveguide. The sensitivity of this sensing structure is nearly two higher than that of traditional electronic thin-film sensors and traditional microphotonic sensors based on evanescent waves. Order of magnitude, the chemical liquid sensor based on the graphene-micro-nano fiber composite structure couples the evanescent wave to the surface of the graphene waveguide through the attachment of the micro-nano fiber to the graphene. When the liquid molecules are in contact with the graphene, the mode of the composite waveguide is The effective refractive index is changed, which causes polarization-dependent attenuation. By detecting the intensity change of the output optical signal, the change in the concentration of the chemical liquid is obtained, which opens the liquid sensing research based on graphene-fiber waveguide, which is the basis for graphene and micro-nano fibers. The effective combination of sensors provides a strong support.

本实施例中基于石墨烯的光纤乳酸传感器其传感原理为：The sensing principle of the graphene-based optical fiber lactic acid sensor in this embodiment is:

氧化镍作为p型氧化物，可以通过电子和空穴进行导电，光波在其中传播，存在吸收损耗，光的电矢量满足有阻尼的波动方程为：As a p-type oxide, nickel oxide can conduct electricity through electrons and holes, and light waves propagate in it, and there is absorption loss. The electric vector of light satisfies the damped wave equation:

式中，σ是电导率，ε ₀是真空介电常数，ε _r是相对介电常数，μ ₀为真空磁导率； where σ is the electrical conductivity, ε ₀ is the vacuum permittivity, ε _r is the relative permittivity, and μ ₀ is the vacuum permeability;

把光波简化为平面电磁波，由波动方程式推导得出导电媒质的光学导纳：Simplify the light wave as a plane electromagnetic wave, and derive the optical admittance of the conductive medium from the wave equation:

N＝n-jk，N=n-jk,

式中，n为折射率，k为消光系数，且：where n is the refractive index, k is the extinction coefficient, and:

n ²-k ²＝ε _r， n ² -k ² =ε _r ,

2nk＝σ/ε ₀ω， 2nk=σ/ε ₀ ω,

求解n，得：Solving for n, we get:

可知，折射率n随电导率σ的增大而增大。It can be seen that the refractive index n increases with the increase of the conductivity σ.

当乳酸分子接触到氧化镍表面时，吸附分子首先在表面自由扩散，失去其运动能量，这些分子向氧化镍放出电子，成为正离子，于是氧化镍的载流子增多，电导率增大，折射率n亦增大；因此，当乳酸液体浓度增大时，其透过率会增加，但是本征NiO镀层电阻率高，其载流子浓度由氧空位决定，难以控制；When lactic acid molecules contact the surface of nickel oxide, the adsorbed molecules first diffuse freely on the surface and lose their motion energy. These molecules release electrons to nickel oxide and become positive ions, so the carriers of nickel oxide increase, conductivity increases, and refraction increases. The rate n also increases; therefore, when the lactic acid liquid concentration increases, its transmittance will increase, but the intrinsic NiO coating resistivity is high, and its carrier concentration is determined by oxygen vacancies, which is difficult to control;

本实施例通过掺杂石墨烯可使NiO在保持可见光区高透过率的同时，改善其导电性；石墨烯作为单层的石墨分子比表面积(≥2600m2/g)大，在室温下具有较高的载流子迁移率，并且还具有完美的量子隧道效应、半整数量子霍尔效应、永不消失的电导率等一系列性质；在氧化镍中引入石墨烯，将会产生更高的载流子浓度，从而得到性能更优良的敏感区。In this embodiment, by doping graphene, NiO can improve its conductivity while maintaining high transmittance in the visible light region; graphene as a single layer of graphite molecules has a large specific surface area (≥2600m2/g), and has a relatively large specific surface area (≥2600m2/g) at room temperature. High carrier mobility, and also has a series of properties such as perfect quantum tunneling effect, half-integer quantum Hall effect, and never-disappearing conductivity; the introduction of graphene into nickel oxide will produce higher carrier The carrier concentration can be obtained to obtain a sensitive area with better performance.

实验验证：Experimental verification:

光纤乳酸传感实验装置主要由化学镀氧化镍石墨烯混合物的光纤传感器、乳酸、PBS缓冲液、乳酸氧化酶溶液、实验室PH计及安立公司出产的台式光谱分析仪MS9740A组成；The optical fiber lactic acid sensing experimental device is mainly composed of an optical fiber sensor with electroless nickel oxide graphene mixture, lactic acid, PBS buffer, lactic acid oxidase solution, laboratory PH meter and desktop spectrum analyzer MS9740A produced by Anritsu;

实验时，采用PH＝7.0的100mM PBS缓冲液配制浓度为5mM、15mM、25mM、35mM、45mM、55mM的乳酸标准溶液，用移液枪移取30μL经PBS缓冲液配制后的乳酸标准溶液至传感器敏感区，谱仪波长1550nm的自带光源，测试不同乳酸浓度下光纤的输出光强，光纤采用的分别为化学镀氧化镍和氧化镍掺杂石墨烯混合物，实验验证所使用的对比例没有加入石墨烯。During the experiment, use 100 mM PBS buffer with pH=7.0 to prepare lactic acid standard solutions with concentrations of 5 mM, 15 mM, 25 mM, 35 mM, 45 mM, and 55 mM, and use a pipette to transfer 30 μL of the lactic acid standard solution prepared with PBS buffer to the sensor. In the sensitive area, the spectrometer has its own light source with a wavelength of 1550 nm to test the output light intensity of the optical fiber under different lactic acid concentrations. The optical fiber adopts chemically plated nickel oxide and nickel oxide doped graphene mixture, and the experimental verification used the comparative example without adding Graphene.

(1)传感器光谱分析(1) Sensor spectrum analysis

如图2(a)-2(b)所示，分别是化学镀氧化镍和掺杂了石墨烯的氧化镍镀层在不同波长下所测得的输出光强度，其纵坐标是输出光强度，横坐标是乳酸浓度；As shown in Figures 2(a)-2(b), the output light intensities of electroless nickel oxide and graphene-doped nickel oxide coatings at different wavelengths are measured respectively, and the ordinate is the output light intensity, The abscissa is the lactate concentration;

采用中心波长为1550nm的自带光源输入光纤，随着乳酸浓度的增加，掺杂石墨烯的氧化镍镀层的熔融拉锥光纤的输出光强逐渐增强，乳酸浓度从0％增加到55％，输出光强度从16000上升到24000，输出的光强度随着乳酸液体浓度的增加而增加，这种趋势是因为随着乳酸浓度的增加氧化镍镀层的电导率增大，导致其折射率n也增加，折射率的增大使得吸收系数α减少，使得输出光强度增大；因为石墨烯的存在，把乳酸分子均匀、紧密的固定在镀层里，可见石墨烯的加入大大提高了输出信号的强度和稳定性；仅仅化学镀氧化镍镀层的光纤对乳酸浓度变化区分度明显低于掺杂了石墨烯的氧化镍镀层光纤。Using a self-contained light source input fiber with a center wavelength of 1550nm, with the increase of lactic acid concentration, the output light intensity of the graphene-doped nickel oxide-coated fused taper fiber gradually increases, and the lactic acid concentration increases from 0% to 55%. The light intensity increased from 16000 to 24000, and the output light intensity increased with the increase of lactic acid liquid concentration. This trend is because the electrical conductivity of the nickel oxide coating increased with the increase of lactic acid concentration, resulting in an increase in its refractive index n. The increase of the refractive index reduces the absorption coefficient α, which increases the output light intensity; because of the existence of graphene, the lactic acid molecules are uniformly and tightly fixed in the coating layer. It can be seen that the addition of graphene greatly improves the intensity and stability of the output signal. The optical fiber with only electroless nickel oxide coating is significantly lower than the nickel oxide coated fiber doped with graphene in distinguishing the change of lactic acid concentration.

(2)传感器稳定性测试(2) Sensor stability test

将折射率传感器置于空气中约10分钟，并每隔一分钟测量其频域干涉谱的峰值频率的漂移情况，记录结果如图3所示，可以看出，十分钟内，该光纤珐珀折射率传感器反射谱的峰值频率漂移量约为±0.062MHz，波动范围为0.024％，其在空气中具有可观的稳定性；The refractive index sensor was placed in the air for about 10 minutes, and the drift of the peak frequency of its frequency-domain interference spectrum was measured every one minute. The recording results are shown in Figure 3. It can be seen that within ten minutes, the fiber optic The peak frequency drift of the reflection spectrum of the refractive index sensor is about ±0.062MHz, and the fluctuation range is 0.024%, which has considerable stability in air;

同样的，将该折射率传感器置于折射率溶液中，溶液的折射率约为1.3，并每隔一分钟测其在微波频域上反射谱的峰值频率漂移情况，持续约10分钟，所记录的结果如图4所示，实验结果显示，在该溶液中，折射率传感器的频率漂移约为±0.031MHz，波动范围为0.012％，由此可知，本实施例设计的传感器具有高稳定性。Similarly, the refractive index sensor was placed in a refractive index solution with a refractive index of about 1.3, and the peak frequency shift of its reflection spectrum in the microwave frequency domain was measured every one minute for about 10 minutes. The results are shown in Figure 4. The experimental results show that in this solution, the frequency drift of the refractive index sensor is about ±0.031MHz, and the fluctuation range is 0.012%. It can be seen that the sensor designed in this example has high stability.

(3)传感器的测量重复性(3) Measurement repeatability of the sensor

要实现该折射率传感器的实际应用，需要该传感器能够长时间稳定工作，并且对于外界折射率的改变具有相同的响应情况，因此对该传感器的重复性进行测试；To realize the practical application of the refractive index sensor, it is required that the sensor can work stably for a long time, and has the same response to the change of the external refractive index, so the repeatability of the sensor is tested;

将传感器轮流放入三种折射率溶液中，放入折射率溶液之前需对传感器进行清洗，以保证溶液的折射率基本保持不变，反复进行后得到实验结果如图5所示，由实验结果可以看到，当外界折射率反复变化后，在同一个折射率点上，传感器的反射谱峰值频率漂移较小。Put the sensor into the three refractive index solutions in turn, and clean the sensor before putting it into the refractive index solution to ensure that the refractive index of the solution remains basically unchanged. After repeated operations, the experimental results are shown in Figure 5. It can be seen that when the external refractive index changes repeatedly, at the same refractive index point, the peak frequency shift of the reflection spectrum of the sensor is small.

实施例2Example 2

本实施例提供一种石墨烯增敏的光纤乳酸传感器的制备方法，包括：The present embodiment provides a method for preparing a graphene-sensitized fiber optic lactic acid sensor, comprising:

将光纤进行熔融拉锥后，在抛磨区域处生长石墨烯，并经氧化处理得到氧化石墨烯层；After the optical fiber is melted and tapered, graphene is grown at the polishing area, and a graphene oxide layer is obtained by oxidation treatment;

在本实施例中，将单模光纤进行拉锥后，通过化学沉积(CVD)方法在光纤抛磨区域直接生长石墨烯，并通过Hummers氧化法制成氧化石墨烯。In this embodiment, after the single-mode optical fiber is tapered, graphene is directly grown on the polished area of the optical fiber by chemical deposition (CVD) method, and graphene oxide is produced by Hummers oxidation method.

在本实施例中，在硫酸镍溶液中，加入醋酸钠、柠檬酸钠和次磷酸钠，加入适量氨水，溶液调节pH值约10得到化学镀溶液；In the present embodiment, in the nickel sulfate solution, sodium acetate, sodium citrate and sodium hypophosphite are added, and an appropriate amount of ammonia water is added, and the pH value of the solution is adjusted to about 10 to obtain an electroless plating solution;

优选地，加入22g/L硫酸镍溶液、35g/L醋酸钠、30g/L柠檬酸钠和25g/L次磷酸钠；Preferably, add 22g/L nickel sulfate solution, 35g/L sodium acetate, 30g/L sodium citrate and 25g/L sodium hypophosphite;

优选地，硫酸镍溶液采用六水合硫酸镍溶液。Preferably, the nickel sulfate solution is a hexahydrate nickel sulfate solution.

在本实施例中，将光纤包覆区浸泡在化学镀溶液中，室温下超声分散30min，70℃恒温水浴35min，进行离心分离、水洗、醇洗、70℃恒温干燥处理。In this embodiment, the optical fiber coating area is immersed in an electroless plating solution, ultrasonically dispersed for 30 minutes at room temperature, and subjected to centrifugal separation, water washing, alcohol washing, and constant temperature drying at 70 °C for 35 minutes.

在更多实施例中，还提供：一种上述石墨烯增敏的光纤乳酸传感器在乳酸浓度检测中的应用。In more embodiments, the application of the above graphene-sensitized optical fiber lactic acid sensor in lactic acid concentration detection is also provided.

在更多实施例中，还提供：一种上述石墨烯增敏的光纤乳酸传感器在肿瘤术后评估中乳酸浓度检测的应用。In more embodiments, the application of the above graphene-sensitized fiber optic lactate sensor in the detection of lactate concentration in tumor postoperative evaluation is also provided.

在更多实施例中，还提供：一种上述石墨烯增敏的光纤乳酸传感器在与人体运动后乳酸浓度检测的应用。In more embodiments, there is also provided: an application of the above graphene-sensitized optical fiber lactic acid sensor in detecting lactic acid concentration after exercising with a human body.

本实施例中基于氧化镍掺杂石墨烯化学镀在熔融拉锥光纤传感器，对乳酸液体浓度的变化进行测量，利用氧化镍与乳酸的特殊络合反应，并且石墨烯良好的吸附特性和原子厚度使得乳酸分子均匀并紧密的吸附在敏感镀层内，实验显示在乳酸浓度从0％到55％与输出光强度有良好并且合理的线性关系以及优良的可恢复性，而且在低浓度范围也有着良好并且合理的线性关系，可对高精度的测量乳酸以及对熔融拉锥光纤传感器的研究提供有效的办法。In this example, based on the electroless plating of nickel oxide doped graphene on the fused taper fiber sensor, the change of the concentration of lactic acid liquid is measured, and the special complex reaction between nickel oxide and lactic acid is used, and graphene has good adsorption characteristics and atomic thickness. The lactic acid molecules are uniformly and tightly adsorbed in the sensitive coating. The experiment shows that the lactic acid concentration from 0% to 55% has a good and reasonable linear relationship with the output light intensity and excellent recoverability, and also has good recovery in the low concentration range. And a reasonable linear relationship can provide an effective method for the high-precision measurement of lactic acid and the research on the fusion taper fiber sensor.

以上仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

上述虽然结合附图对本发明的具体实施方式进行了描述，但并非对本发明保护范围的限制，所属领域技术人员应该明白，在本发明的技术方案的基础上，本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本发明的保护范围以内。Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the scope of protection of the present invention. Those skilled in the art should understand that on the basis of the technical solutions of the present invention, those skilled in the art do not need to pay creative work. Various modifications or deformations that can be made are still within the protection scope of the present invention.

Claims

一种石墨烯增敏的光纤乳酸传感器，其特征在于，包括：光纤和镍镀层；在所述光纤经熔融拉锥后的抛磨区域处生长石墨烯层，在石墨烯层处涂覆所述镍镀层。A graphene-sensitized optical fiber lactic acid sensor, comprising: an optical fiber and a nickel coating; a graphene layer is grown at the polishing area after the optical fiber is fused and tapered, and the graphene layer is coated with the described Nickel plating.
如权利要求1所述的一种石墨烯增敏的光纤乳酸传感器，其特征在于，所述光纤为单模光纤。The graphene-sensitized optical fiber lactic acid sensor according to claim 1, wherein the optical fiber is a single-mode optical fiber.
如权利要求1所述的一种石墨烯增敏的光纤乳酸传感器，其特征在于，采用化学沉积CVD方法在抛磨区域生长石墨烯层。A kind of graphene-sensitized optical fiber lactic acid sensor as claimed in claim 1, is characterized in that, adopts chemical deposition CVD method to grow graphene layer in polishing area.
如权利要求3所述的一种石墨烯增敏的光纤乳酸传感器，其特征在于，对生长的石墨烯层通过Hummers氧化法制成氧化石墨烯层。A kind of graphene-sensitized optical fiber lactic acid sensor as claimed in claim 3, is characterized in that, the graphene oxide layer is made by Hummers oxidation method to the grown graphene layer.
一种石墨烯增敏的光纤乳酸传感器的制备方法，其特征在于，包括：A preparation method of a graphene-sensitized optical fiber lactic acid sensor, characterized in that, comprising:

将光纤进行熔融拉锥后，在抛磨区域处生长石墨烯，并经氧化处理得到氧化石墨烯层；After the optical fiber is melted and tapered, graphene is grown at the polishing area, and a graphene oxide layer is obtained by oxidation treatment;

由硫酸镍溶液与还原剂溶液制备镍镀溶液，将光纤的氧化石墨烯层浸泡在镍镀溶液中。A nickel plating solution is prepared from a nickel sulfate solution and a reducing agent solution, and the graphene oxide layer of the optical fiber is immersed in the nickel plating solution.
如权利要求5所述的一种石墨烯增敏的光纤乳酸传感器的制备方法，其特征在于，在硫酸镍溶液中加入醋酸钠、柠檬酸钠和次磷酸钠，并调节pH值得到镍镀溶液。The method for preparing a graphene-sensitized fiber optic lactic acid sensor according to claim 5, wherein sodium acetate, sodium citrate and sodium hypophosphite are added to the nickel sulfate solution, and the pH value is adjusted to obtain a nickel plating solution .
如权利要求6所述的一种石墨烯增敏的光纤乳酸传感器的制备方法，其特征在于，所述硫酸镍溶液浓度为22g/L，在硫酸镍溶液中加入35g/L的醋酸钠、30g/L的柠檬酸钠和25g/L的次磷酸钠。The preparation method of a graphene-sensitized fiber optic lactic acid sensor according to claim 6, wherein the nickel sulfate solution concentration is 22g/L, and 35g/L sodium acetate, 30g/L sodium acetate, 30g /L of sodium citrate and 25g/L of sodium hypophosphite.
如权利要求6所述的一种石墨烯增敏的光纤乳酸传感器的制备方法，其特征在于，所述pH值调节为10。The preparation method of a kind of graphene-sensitized optical fiber lactic acid sensor as claimed in claim 6, is characterized in that, described pH value is adjusted to 10.
如权利要求5所述的一种石墨烯增敏的光纤乳酸传感器的制备方法，其特征在于，将光纤的氧化石墨烯层浸泡在镍镀溶液中具体包括：室温下超声分散30min，70℃恒温水浴35min，进行离心分离、水洗、醇洗和70℃恒温干燥处理。The preparation method of a graphene-sensitized optical fiber lactic acid sensor according to claim 5, wherein the immersion of the graphene oxide layer of the optical fiber in the nickel plating solution specifically comprises: ultrasonic dispersion at room temperature for 30 min, constant temperature at 70 °C In a water bath for 35 min, centrifugation, water washing, alcohol washing and drying at 70°C were performed.
一种权利要求1-4任一项所述的石墨烯增敏的光纤乳酸传感器在乳酸浓度检测中的应用。A kind of application of the graphene-sensitized optical fiber lactic acid sensor according to any one of claims 1-4 in lactic acid concentration detection.