The Detection Of Small Molecular Environmental Pollutants Based On Polythiophene Nanocomposites

The small molecular environmental pollutants have lower molecular weight,especially small organic molecules, which include environmental estrogen,organo-chlorine pesticide and organophosphorus pesticide. BPA is a typical example of small molecular environmental pollutants. In this thesis, we constracted the new sensors based on nanocomposites and biological materials in order to detect BPA.1. A facile and eco-friendly electrochemical sensor based on a multi-walled carbon nanotubes/ polythiophene/Pt nanocomposites-modified glassy carbon electrode for determination of bisphenol A(BPA) was constructed using the MWCNT/PTh/Pt nanocomposites to modify glassy carbon(GC). The obtained electrochemical sensor MWCNT/PTh/Pt for BPA takes advantages of the large specific surface area of the PTh and Pt nanostructures, the excellent adsorption properties and electrochemical properties of the MWCNTs. Under the optimal conditions, the response of the as-prepared sensor to BPA was linear in the BPA concentration range from 5.0 × 10-8 mol·L-1 to 4.0 × 10-7 mol·L-1 and the detection limit was 3.0 × 10-9 mol·L-1 according to 3σ rule. The results revealed that the developed sensor exhibited high sensitivity and selectivity, more excellent electrochemical performance compared to BPA and that it allowed for BPA detection in water samples.2. In this section, the function of Au-S bond between Au electrode and DNA aptamers of BPA, and the base pairing between DNA were used to prepare a new sensor for BPA detection. After that, BPA was detected by fluorescent technique.Besides, the response time, cultivation temperature, cultivation time and pH values were optimized. Finally, the response of the fluorescence biosensor to BPA was linear in the BPA concentration range from 1.0 × 10-10 mol·L-1 to 1.0 × 10-5 mol·L-1 and the detection limit was 2.0 × 10-11 mol·L-1. The as-prepared fluorescence biosensor has potential application value, which can be simply prepared with especial selectivity.3. This experiment was based on the as-prepared aptamer biosensor and ICP-MS technology to detect BPA indirectly. ICP-MS technology was usually used to detect inorganic ions and had higher requirements for testing environment. The combination of biosensor and ICP-MS technology could expand the type of analyte.Under the optimal conditions, we detected BPA in the use of sensors and ICP-MS technology and the linear range for the detection of BPA was from 1.0 × 10-11 mol·L-1to 1.0 × 10-6 mol·L-1, while the detection limit was 5.0 × 10-12 mol·L-1. Good selectivity, sensitivity and repeatability are advantages of this BPA sensor which is feasible.