Novel Impedance/Capacitive Sensor For The Detection Of Environmental Contaminants

In order to improve the industrial and agricultural production level,chemical reagents have been widely used,thus leading to the strong explosion and leakage problems.These directly do harm to people's daily life.Therefore,the detection of environmental pollutants has attracted great attention for human health and environmental control.Presently,sensor based on electrochemical method has been widely used due to the advantages of simple design,low cost,high sensitivity and easy to realize miniaturization.Based on this,this thesis mainly focuses on the following three aspects by using the electrochemical method to detect perfluorooctanic acid(PFOA),acephatemet(AM)and kanamycin in the environment:1.In this paper,we successfully prepared the molecularly imprinted polymer(MIP)of PFOA.Owing to the high degree of integration and miniaturization,the interdigital electrode was used to fabricate a novel impedance sensor,combined with the molecularly imprinted technology(MIT)for the detection of PFOA.The as-prepared sensor demonstrates high selectivity and sensitivity for the detection of target molecule.In addition,this economical and sensitive device has been successfully used for the determination of PFOA in actual water samples.2.The organic-inorganic hybrid ultrathin films(GO/PDDA@CNs)were fabricated by alternate assembly of positively charged poly alkenyl propionic dimethyl ammonium chloride(PDDA)and negatively charged graphite oxide(GO)using carbon nanospheres(CNs)selected as substrates via a layer-by-layer(LBL)approach.Beta cyclodextrin(?-CD)was finally assembled onto the surface of the hybrid ultrathin films(labeled as?-CD/GO/PDDA@CNs).Based on the external hydrophilic and internal hydrophobic characteristic of the P-CD and the selectivity of its cavity,a new kind of impedance sensor has been fabricated for the detection of AM.The resulting electrochemical sensor has the advantages of high stability,sensitivity and selectivity,which also can be successfully used to detect AM in the real samples.3.A capacitive sensor for the detection of kanamycin has been developed using the molecularly imprinted chitosan nanofiber combined with the electrospinning technique.The as-prepared electrode showed an obvious capacitance response that is clearly dependent on the concentration of kanamycin with highly sensitivity and selectivity.The whole detection process has the advantages of simple operation,low cost,short detection time and good stability.To achieve the aim of practical applications,this simple with low cost and high efficiency probe was further tested by monitoring kanamycin in real samples.