Studies On Metal Ion-Selective Electrodes And Carbon Nanotubes Modified Electrodes:Application

The metal in our production and life is in a large range of applications. As mining, sewerage irrigation, exhaust emission, smelting, processing and commercial manufacturing activities increased, a large of heavy metals such as lead, cadmium, mercury, etc. are discharged into the environment. Customarily, metal pollution is mostly caused by heavy metals and their toxic substances, which result in environmental pollution. This pollution gets across food chains into biogeocenose and enriches in the body and biogeocenose. When their concentration exceeds a certain limit, they will result in strong toxicity to the organism. Nowadays, the importance of controlling the level of environmental pollutants has generated increasing interest in the development of new methods for the detection of metals ions. At present, the available methods are used to determine metals ions such as atomic absorption spectrometry, flame photometry, inductively coupled plasma atomic emission spectrometry, isotope dilutionmass spectrometry, neutron activation analysis, inductively coupled plasma mass spectrometry, X-ray fluorescence spectrometry, etc. But, these methods are time consuming, not suitable for large scale monitoring, involving multiple sample pretreatment and relatively expensive. Thus, it is necessary to develop a sensitive, economical and convenient method to determine metals ions. Ion-selective electrodes (ISEs) that offer many advantages, such as easy handling, non-destructive analysis, good accuracy, fast response time, good selectivity, high sensitivity, simplicity and low cost, etc. have been proposed as a convenient method for environmental analysis and ionic species determination. In the past few decades, many ion selective electrodes based on different ionophores have been reported. At present, using new materials in the ion selective electrode is a very active direction on the studies of the ion selective electrodes. In this paper, we emphatically focus on the design, synthesis of novel complexes and new materials which are used as ionophores of PVC membrane electrode and carbon paste electrode. At the same time, the proposed electrodes are applied to the detection of metal ions in real samples.1. Studies on the2-((E)-((Z)-2-(methylimino)benzofuran-3(2H)-ylidene)amino)-benzoic acid (BFYABA) application on Fe (Ⅲ) ion selective electrode A novel selective Fe(Ⅲ) PVC membrane electrode based on the2-((E)-((Z)-2-(methylimino)benzofuran-3(2H)-ylidene)amino)-benzoic acid (BFYABA) as ionophore has been developed. Its performance is compared with recently reported electrodes in many respects and shows significant superiority over them, good selectivity, stability and reproducibility. The response mechanism was discussed in view of the AC impedance technique. It was used as an indicator electrode in potentiometric titration of Fe3+against EDTA. At the same time, the electrode was successfully applied to the determination of Fe3+in wastewater.2. Studies on a new Multi-walled Carbon Nanotubes (MWCNTs) derivates as ionophore of carbon paste sensor of Fe3+A carbon paste selective electrode based on a ionophore2-Amino-5-mercapto-1,3,4-thiadiazole-Multi-walled Carbon Nanotubes (AMT-MWCNTs) derivates for detection of FeJ*was proposed. The response performances of the electrode have gnificantly improved. Moreover, it also shows a high selectivity and a long life time (more than3months). The selectivity coefficients of Fe3+carbon paste electrode were determined by the separate solution method (SSM). The electrode is selective towards Fe3+ion over a lot of other cations, as the selectivity coefficient value is slightly lower. Importantly, the response mechanism of the proposed electrode was investigated by using AC impedance and UV-visible spectroscopic techniques.3. Studies on Derivatized Multi-walled Carbon Nanotubes application on Al3+carbon paste electrodeA new derivatized multi-walled carbon nanotubes-based A13+carbon paste electrode is reported. The introduce of carbon nanotubes in the electrode, have largely improved the performance of the Al3+electrode, such as Nernstian linear range, detection limit, pH range, response time. Moreover, it also shows a high selectivity and a long life time (more than3months). The selectivity coefficients of Al3-carbon paste electrode were determined by the separate solution method (SSM). The electrode is selective towards Al3-ion over a lot of other cations, as the selectivity coefficient value is slightly higher. Importantly, the response mechanism of the proposed electrode was investigated by using AC impedance and UV-visible spectroscopic techniques. Finally, the electrode was successfully applied for the determination of A13+ion concentration in environmental samples.