| Heavy metal pollution refers to the environmental pollution caused by heavy metal and its compounds. Heavy metal pollution mainly includes industrial pollution, traffic pollution, daily garbage pollution and agriculture pollution. Industrial pollution mainly refers to waste residue, waste water, waste gas industry. Traffic pollution mainly refers to the automobile exhaust emissions. daily garbage pollution mainly refers to waste batteries, broken lamp, unspent cosmetics, color-glazed dishes and so on. Agricultural pollution mainly refers to the fertilizer and pesticide pollution. Heavy metal pollution is different from organic compounds pollution. The toxicity of organic compounds pollution may be reduced by the physical, chemical or biological purification of nature. While the heavy metals will accumulate, it is difficult to degrade, and it will bring great harm to the environmental and living things. The strong interaction between heavy metals and proteins results in proteins lose activity. If the heavy metal exceeds the limit of the human body can withstand, human body poisoning, people will be poisoned. Therefore, it is imminent to explore a new method to detect the content of these heavy metal pollutants. Currently, the most common methods used to detect the content of these heavy metal pollutants are inductively coupled plasma atomic emission spectrometry,spectrophotometry, atomic absorption spectrometry, fluorescence, chromatography etc. However, most of these methods are followed with high cost of equipment, time-consuming and complicated preparation of sample. So, it is necessary to develop a sensitive, convenient and economical method to detect the content of these heavy metal pollutants. Nano-materials has a prosperous application prospects in fabricating the electrochemical sensor due to its surface and interface effect, small size effect, quantum size effect, macroscopic quantum tunneling effect. Because of the excellent properties of nano-materials integrated into the particle’s operation, the construction of chemical sensor based on nano-material can improve the chemical sensor’s performance. In this paper, we prepared nanocomposites with different properties using carbon nanotubes, graphene oxide, gold nanoparticals, Fe3O4nanoparticles, and the nanocomposites were used as electrode materials in constructing the interface of ion selective electrode. The prepared ion selective electrodes have excellent performance.This paper studies the content of the following: 1. Functionalized graphene oxide-based carbon paste electrode for potentiometric detection of copper ion (II)For the first time, a novel copper ion (II) carbon paste electrode (CPE) based on high-density carboxyl functionalized graphene oxide (GO) is reported. A new hybrid material,2-amino-5-mercapto-1,3,4-thiiodiazole grafting on nanoscale graphene oxide (AMT-g-NGO), was introduced as a neutral carrier. The electrode exhibits an excellent Nernstian response to copper ion (II) ranging from1.0×10-7mol/L to1.0×10-1mol/L with a slope of26.2mV/dec. Meanwhile, the proposed electrode shows a fairly good selectivity and a long life time (2months). Moreover, the excellent performance on low detection limit (4.0×10-8mol/L), wide applicable pH range (3.0-7.0), fast response time (15s) reveal the superiority of the electrode. The response mechanism of the electrode was investigated using AC impedance technique and UV-vis spectroscopy. The sensor can be used as indicator electrode for potentiometric titration of Cu2+ion with EDTA and successfully applied for the determination of Cu2+ion in different real samples.2. Improved potentiometric response of solid-contact Lanthanum (III) selective electrodeFor the first time, the analytical application of integrate ionophore-transducer material based on magnetic graphene hybrids and2,2-dithiodipyridine (DTDP) in solid-contact lanthanum (Ⅲ) selective electrode is reported. The attachment of Fe3O4nanoparticles (NPs) to graphene oxide (GO) for magnetic graphene hybrid is achieved by covalent bonding, and the universal problem, Fe3O4NPs may easily leach out from the graphene during application, is successfully solved by the method above. The proposed electrode exhibits an excellent near-Nernstian response to lanthanum (Ⅲ) ranging from1.0×10-9to1.0×10-3mol/L with a slope of17.81mV/dec. Moreover, the excellent performance on fairly good selectivity, wide applicable pH range (3.0-8.0), fast response time (10s) and long life time (2months) reveal the superiority of the electrode. Most importantly, we have made a great improvement in the detection limit (2.75×10-10mol/L), which brings new dawn to the real-time detection of lanthanum(Ⅲ) using ion selective electrode.3. Nanostructured assemblies for ion-sensors:strongly coupled organic-metallic-carbon hybrid materials for silver (Ⅰ) determinationAs a new transducing layer, the strongly coupled hybrids (SC-hybrids) of a three-dimensional (3-D) hierarchical structure carbon nanomaterials, Au nanoparticals (NPs) and dithiocarbamate (DTC) applicated in silver (Ⅰ) selective electrode for the first time. Carbon nanotubes (CNTs) were introduced as the spacer in fabricating the3-D hierarchical structure. We described the spontaneous assembly of dithiocarbamate ligands on Au surfaces, by simple exposure to carbon disulfide and phenothiazine (PTZ). What’s more, the issues of accessibility and robustness in the functionalization of metal substrates with organic ligands were addressed by the method above. We show that the SC-hybrids represent a new approach to synthesize electrode materials with high electrochemical performance. The proposed electrode exhibits an excellent near-Nernstian response to silver (Ⅰ) ranging from5.3×10-7to1.0×10-1mol/Lwith a slope of54.3mV/dec. Moreover, it also showed excellent performance on selectivity, detection limit, applicable pH range, response time and lifetime. All the results indicate that the SC-hybrids are attractive alternatives in the fields of chemo-biosensors. |
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