碳纳米电阻传感器制备及用于环境污染物检测

发布时间：2018-05-10 18:24

本文选题：碳纳米管 + 石墨烯　；参考：《大连理工大学》2015年硕士论文

【摘要】：发展水体中痕量污染物的检测方法对于保障水体质量和公共卫生意义重大。基于传感器的检测方法有响应快速、灵敏度高、易于操作等诸多优点,在环境污染物的现场检测方面有着巨大的潜力。近年来,碳纳米管和石墨烯由于优异的光学、电学等特性,在传感器领域获得了广泛的应用。本论文分别构建了基于单壁碳纳米管和石墨烯的电阻传感器,用于水体中微囊藻毒素-LR (MC-LR)和双酚A(BPA)的检测。具体内容如下：采用光刻和磁溅射工艺在SiO2/Si表面制备了金叉指电极。利用氨丙基三乙氧基硅烷(APTES)对金叉指电极进行修饰。然后成功将单壁碳纳米管(SWCNTs)沉积在金叉指电极表面,构建了CNT电阻传感器。扫描电镜(SEM)表明,CNT在金叉指电极沟道内形成均匀、致密的网络,可以作为传感器导电的沟道。为检测MC-LR,首先把MC-LR固定到SWCNTs修饰的金叉指电极上,再接着连接上抗MC-LR单克隆抗体。新加入的MC-LR样品通过竞争键合作用诱导SWCNTs上抗体-抗原复合物的抗体分离,这导致传感器的电导发生变化。无标记的免疫传感器对取以10为底的浓度在1-1000 ng/L的MC-LR有着广泛的线性响应,检测限为0.6 ng/L。将该传感器用于添加MC-LR的自来水、河水和湖泊水样品的分析,回收率分别为96.5～112.6%,102.2～124.2%和84.7～104.7%,相对标准偏差(RSDs)为9.1～18.7%。将单层氧化石墨烯(GO)沉积在APTES功能化的金叉指电极表面,利用单线性扫描伏安法(LSV)对电极表面的GO进行电化学还原,然后在250℃空气氛围下热退火。SEM分析表明,沉积的GO均匀覆盖在金叉指电极表面,形成了传感器导电的沟道。拉曼分析和电化学测量表明,十次单线性扫描伏安扫描和热退火可将传感器的电阻进一步降低。为检测BPA,我们选择了对BPA具有特异性识别的单链DNA适配子(序列：(5'-(NH2C3)CCGGTGGGTGGTCAGGTGGGATAGCGTTCCGCGTATGGCCCAGCGC ATCACGGGTTCGCACCA-3'),适配子会通过物理吸附方式附着在还原的GO表面。同时考察了DNA适配子浓度的影响,结果表明,使用500 nmol/L的DNA适配子进行修饰可以获得最佳的响应特性。免疫电阻传感器对浓度在1-500 nmol/L BPA有着线性的响应,检测限为0.7 nmol/L。将该传感器用于添加BPA的河水和自来水样品的分析,回收率分别为82.7～92.8%和102.2～120.1%,相对标准偏差(RSDs)为9.2～20.7%。
[Abstract]:It is of great significance to develop the detection method of trace pollutants in water body to ensure water quality and public health. The detection method based on sensor has many advantages, such as fast response, high sensitivity, easy to operate and so on, so it has great potential in the field detection of environmental pollutants. In recent years, carbon nanotubes and graphene have been widely used in sensor field due to their excellent optical and electrical properties. In this paper, resistance sensors based on single-walled carbon nanotubes and graphene were constructed for the detection of microcystin-LR (MC-LR) and bisphenol A (BPA) in water. The main contents are as follows: gold finger electrode was fabricated on SiO2/Si surface by photolithography and magnetron sputtering. The gold interDigital electrode was modified with aminopropyl triethoxy silane (APTES). Then the single walled carbon nanotubes (SWCNTs) were successfully deposited on the surface of the gold finger electrode and the CNT resistor sensor was constructed. Scanning electron microscopy (SEM) showed that CNT formed a uniform and dense network in the channel of the gold finger electrode and could be used as the conductive channel of the sensor. In order to detect MC-LRs, MC-LR was first immobilized on the gold finger electrode modified by SWCNTs, and then the monoclonal antibody against MC-LR was attached. The newly added MC-LR samples are separated by competitive bonding to induce antibody separation of the antibody-antigen complex on SWCNTs, which results in the change of the conductivity of the sensor. The unlabeled immunosensor has a broad linear response to MC-LR with a concentration of 10 to 1-1000 ng/L, with a detection limit of 0.6 ng / L. The sensor was applied to the analysis of tap water, river water and lake water with MC-LR. The recoveries of the sensor were 96.5 ~ 112.6% and 84.7% ~ 104.2%, respectively, and the relative standard deviation (RSD) was 9.1 ~ 18.7%. Single layer graphene oxide (GOO) was deposited on the surface of APTES functionalized gold finger electrode. Go on the electrode surface was reduced by single linear scanning voltammetry. The deposited go is uniformly covered on the surface of the gold finger electrode, forming a channel for conducting the sensor. Raman analysis and electrochemical measurements show that the resistance of the sensor can be further reduced by single linear scanning voltammetry and thermal annealing. In order to detect the BPA, we selected a single-stranded DNA adaptor (sequence: 5) -NH2C3 / CCGGTGGGGGGGATAGTAGTAGTTCCGTAGGGGC ATCACGGGGTTCGCACCA-3, which is attached to the reduced go surface by physical adsorption. At the same time, the effect of DNA adaptor concentration was investigated. The results show that the best response characteristics can be obtained by modifying 500 nmol/L DNA adaptor. The immunoresistive sensor has a linear response to the concentration of 1-500 nmol/L BPA, with a detection limit of 0.7 nmol / L. The sensor was applied to the analysis of water and tap water samples with BPA. The recoveries were 82.7% and 102.2%, respectively. The relative standard deviation (RSDs) was 9.2% and 20.7%, respectively.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X830;TP212

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