用于检测重金属离子电化学传感器的研究

【作者】 喻鹏；

【导师】 司士辉；

【作者基本信息】 中南大学 ， 分析化学， 2011， 硕士

【摘要】 本文以电化学分析为技术手段,研究制备出一次性电化学传感器。制备出的一次性电化学传感器具有成本低廉、性能优良、重现性好等优点,十分适合用作在线分析检测的工作探头,为新型的仪器开发奠定了良好的研究基础。本文首先研究了电化学分析手段测定痕量汞方法的改良。直接采用传统的工作电极——玻碳电极测定汞难以达到我们需要的精度,不能满足实际测定的要求,通过对玻碳电极进行表面化学修饰,增强了电极表面和汞离子的键合效率,从而有效地提高了沉积的效率,使测定的灵敏度更高,检测限更低,测定痕量汞的线性范围为2.0～20.0μg/L,检测的最低浓度为2.0μg/L,线性回归方程为y=0.0167x+0.0579。接着分别采用汞膜修饰玻碳电极和铋膜修饰玻碳电极对铜的测定进行了对比研究,结果表明,原位镀汞溶出伏安法测量铜的最低浓度为4.0μg/L,线性范围为4.0-200.Oμg/L,回归方程为y=0.0539x+0.0753,同位镀铋溶出伏安法测量铜的最低浓度为20.0μg/L,线性范围为20.0-200.0μg/L,回归方程y=0.0788x+0.7564。汞膜电极的测定铜的效果更好,但考虑到铋膜电极已能达到我们的测定需求,以及汞膜电极会对环境造成二次污染,得出铋膜电极可以取代汞膜电极,成为新型的环保型电极。在以上的电化学分析研究基础上,着手研究一次性电化学传感器。通过对比研究丝网印刷工艺和热压成膜工艺制作的一次性电化学传感器,发现热压成膜工艺制作的传感器表面更加致密和均匀,表面更加光滑和洁净,能同时测定铜、铅、镉、锌四种重金属离子,测定的最佳条件为：在0.2mol/L的HAc-NaAc(pH=5)的缓冲溶液中,富集时间选为300s,采用线性扫描溶出伏安法进行测定,检测限可达到ppb级。更多还原

【Abstract】 This paper will eventually prepare solve a disposable electrochemical sensor by electrochemical techniques. Disposable electrochemical sensors we prepared have low-cost, excellent performance and good reproducibility, which is very suitable for the work probe in electrical analysis and provides a good basis for the further study of development of new instruments.This paper studies the improved electrochemical analysis method for the determination of trace mercury. The traditional electrode---glassy carbon electrode for the determination of mercury is difficult to achieve the precision we need and can not meet the requirements of the actual measurement. Through chemically modified the surface of glassy carbon electrode, the efficiency of mercury ion binding and depositing on the electrode surface are effectively improved. So we have the more sensitive determination and lower detection limit. The peak currents are linear with the concentrations in the range of 2.0～20.0μg/L and the linear equation is y=0.0167x+0.0579 for Hg2+. And the detection limit is 2.0μg/L for Hg2+.Then with mercury film modified glassy carbon electrode and bismuth film modified glassy carbon electrode respectively, we have a comparative study for determination of copper. The results show that the peak currents are linear with the concentrations in the range of 4.0-200.0μg/L on the mercury film electrode and 20.0～200.0μg/L on the bismuth film electrode. The linear equation is y=0.0539x+0.0753 on the mercury film electrode and y=0.0788x+0.7564 on the bismuth film electrode for Cu2+. And the detection limit is 4μg/L on the mercury film electrode and 20μg/L on the bismuth film electrode for Cu2+ respectively. But considering that the bismuth film electrode has been able to achieve our needs of determination and mercury film electrode causes secondary pollution on the environment, bismuth film electrode can replace the mercury film electrode and be a new type of environmentally friendly electrode.With the aboved basis of electrochemical analysis, we set out to study the disposable electrochemical sensors. With the comparative study between the screen printing process and the hot forming process for the production of disposable electrochemical sensors, we found that the sensor with the latter technology has denser, smoother and cleaner surface. When we use the best solution HAc-NaAc (pH=5,0.2mol/L) and the desposition time is 300s, it can simultaneously determinate copper, lead, cadmium, zinc with the detection limit of ppb level with anodic stripping voltammetry.更多还原