基于复合膜修饰ITO电极的乙醇传感器的研究

发布时间：2018-04-15 10:20

  本文选题：乙醇 + 多壁碳纳米管　； 参考：《重庆医科大学》2011年硕士论文

【摘要】：目的 在医学、法医学、食品安全检测、环境等领域,C_2H_5OH的测定都具有重要的意义。尤其随着经济的发展,醉酒驾驶逐渐增多,故血液中酒精浓度的定量快速检测的意义日益重要。电化学生物传感器检测法由于具有较高的灵敏度,较宽的线性范围,快速的响应时间而逐渐成为血液中酒精含量测定方法研究的热点。 MWCNTs是一种纳米级的兼具有金属性和半导体性的材料。该材料具有导电性强、较大的比表面积和良好的电催化活性,是一种被广泛采用的电子传递媒介体。在电化学生物传感器电活性物质的电子传递过程中已被证实效果显著。PB纳米粒子具有的纳米级尺寸效应,同时可降低氧化还原物质尤其是过氧化物电化学反应的过电位;PB结构稳定,并具有优越的催化活性和良好的电子可逆传递效应。ITO电极是镀有氧化铟锡薄膜的一种电极。其化学性质稳定、易于制得,同时具有导电性和催化性。本实验利用羧基化的多壁碳纳米管(MWCNTs)修饰氧化铟锡(ITO)电极,并在其表面吸附一层纳米普鲁士蓝(PB)颗粒作为电子介体制作一种新型的乙醇传感器。通过该方法实现了对乙醇的直接电化学催化,并放大电响应信号,从而为建立一种新的检测血中C_2H_5OH电化学方法奠定了基础。 方法 (1)将ITO玻璃切割均匀,制备成ITO条形电极。 (2)将5mg纯化的多壁碳纳米管超声分散在50mL N,N-二甲基甲酰胺(DMF)中。超声处理10 min,制备成1.0mg/mL的MWCNTs分散悬浮液。取20μL分散液滴涂于ITO电极上(0.6×0.6cm~2),得到碳纳米管修饰电极(MWCNT/ITO)。然后在PBS(pH=7.0)缓冲溶液中循环伏安扫描,分析修饰了MWCNTs的ITO电极的性能。 (3)将5mmol/L K_3Fe(CN)_6溶液100mL在磁力搅拌下缓慢加入到100mL 5mmol/L FeCl_3(pH=1)中,搅拌3h得到Nano-PB胶体溶液。然后将前期制备好的MWCNTs/ITO电极浸泡在纳米PB溶液中,通过静电吸附,在MWCNTs/ITO电极表面形成均匀的纳米PB膜。将该复合电极分别在PBS和PBS+C_2H_5OH溶液中采用循环伏安法扫描,考察制备的电极的最优性能和测试条件。 (4)通过采用气相色谱法测定血液中乙醇浓度进行平行比较,测定MWCNTs/PB/ITO复合电极的性能。 结果 在ITO电极上自组装一层MWCNTs,然后通过静电吸附修饰上一层纳米普鲁士蓝膜,制备出性能良好的乙醇生物传感器。所制备传感器对乙醇具有明显的电化学活性,线性范围为0.5～10mmol/L,在S/N=3的情况下,检出限为0.07mmol/L(R=0.9968),达到95%稳态响应时间约为15s。 将MWCNTs/ITO电极浸入纳米普鲁士蓝溶液中,分别在2、4、8、16小时后取出。并将制备好的不同MWCNTs/PB/ITO复合电极分别在0.02mol/L的PBS溶液中采用循环伏安法扫描,其电流响应值随浸泡时间的增加而逐渐增大,在达到8小时后变化趋于平稳。同时将优化好的复合电极分别在不同温度、pH值及扫描速率中进行考察,得出该复合传感器在室温25摄氏度、pH=7.0的条件下以50mv/s的速率扫描为最优化条件。 用此法制备的C2H5OH电化学生物传感器具有较高的催化活性,较低的检测限,较快的检测速度,将该电化学生物传感器用于C_2H_5OH的实际检测,结果令人满意。 结论 本实验首先在ITO电极上自组装一层MWCNTs,然后通过静电吸附修饰一层纳米普鲁士蓝复合膜,制备出新型的C_2H_5OH电化学生物传感器。该传感器制作方法简单、可靠,催化性能良好,检测时间快速,检测结果基本准确,具有良好的应用发展前景。
[Abstract]:Purpose


In the fields of medicine , forensic medicine , food safety detection , environment and so on , the determination of C _ 2H _ 5OH is of great significance . Especially with the development of economy , the importance of quantitative rapid detection of alcohol concentration in blood is becoming more and more important .


MWCNTs is a kind of nano - scale material with both metallic and semiconducting properties . The material has strong electrical conductivity , larger specific surface area and good electrocatalysis activity . It is a widely used electron transfer medium . It has been proved to be a kind of electrode of indium tin oxide film .


method


( 1 ) cutting the ITO glass evenly to prepare an ITO strip electrode .


( 2 ) 5 mg of purified multi - walled carbon nanotubes were ultrasonically dispersed in 50 mL of N , N - dimethylformamide ( DMF ) . Ultrasonic treatment was performed for 10 min to prepare 1.0 mg / mL MWCNTs dispersion suspension . 20 渭L of dispersed droplets were applied to ITO electrodes ( 0.6 脳 0.6cm ~ 2 ) to obtain carbon nanotube modified electrode ( MWCNT / ITO ) . The performance of ITO electrode modified MWCNTs was analyzed by cyclic voltammetry scanning in PBS ( pH = 7.0 ) buffer solution .


( 3 ) The solution of 5mmol / L K _ 3Fe ( CN ) _ 6 was slowly added to 100 mL of 5 mmol / L FeCl3 ( pH = 1 ) under magnetic stirring and stirred for 3 h to obtain the Nano - PB colloidal solution . The MWCNTs / ITO electrode prepared in the earlier stage was immersed in the nano - PB solution , and a uniform nano - PB film was formed on the surface of MWCNTs / ITO electrode by electrostatic adsorption . The optimal performance and test conditions of the prepared electrode were investigated by cyclic voltammetry scanning in PBS and PBS + C _ 2H _ 5OH solution .


( 4 ) The performance of MWCNTs / PB / ITO composite electrode was determined by comparing the concentration of ethanol in blood by gas chromatography .


Results


In the presence of S / N = 3 , the detection limit is 0.07 mmol / L ( R = 0.9968 ) , and the steady - state response time of 95 % is about 15 s .


The MWCNTs / ITO electrodes were immersed in the solution of nano - pruculine blue , and then taken out after 2 , 4 , 8 and 16 hours respectively . The prepared MWCNTs / PB / ITO composite electrode was scanned in 0.02mol / L PBS solution . The current response value of MWCNTs / ITO electrode was gradually increased with the increase of immersion time . At the same time , the optimized composite electrode was scanned at different temperature , pH value and scanning rate , and the optimized composite electrode was scanned at 50 mv / s at room temperature at 25 鈩，

本文编号：1753704