Design Of Fluorescent Nanoparticles Self-assembled Multilayers And Interfacial Recognition For Organophosphorus Pesticides

Self-assembled monolayers (self-assembled monolayers, SAMs) belongs to a supramolecular structure of a particular function or performance with a combination of certainty and stability, which is spontaneously formed in the balance conditions by the molecules'non-covalent bond (hydrogen bonding, vanderwaals force, static electricity, hydrophobic interaction,π-πstacking role, cation - adsorption, etc.). The fluorescence analysis is an important method of chemical spectrum analysis. Combinating with the two techniques, according to performance of self-assembled molecular and the substrate, a high sensitive and selective fluorescent sensor with good stability and regeneration is designed. The method has a good applicable future in the detection of contamination in the environment, especially for OPs. Main contents of this paper are as follows:1. The fabrication of indole (ID) self-assembled multilayers (SAMs) and fluorescence interfacial recognition for organophosphorus pesticides were detailed. ID/L-Cys/AuNP/APES/Quartz film is constructed on the L-cysteine (L-Cys) modified AuNP/APES/Quartz surface via the electrostatic attraction between ID and L-Cys. The developed self-assembled multilayer films (ID/L-Cys/AuNP/APES/Quartz) combining with the fluorescence detection methodologies could be used to make microanalysis of organophosphorus pesticides. The performance of SAMs was optimized with respect to operating conditions. Under the optimal conditions, the detection limit of the SAMs for methylparathion and monocrotophos is 6.1×10-8 g L^-1, 3.28×10-6 g L^-1 respectively.2. Via the action ofβ-CD embeddingβ-NA, as well as condensation polymerization between acetylcholinesterase (ACHE) and glutaricdialdehye (GA),β-CD and ACHE were assembled onto dodecanethiol (C12SH) medified SAMs (C12SH /AuNP/APES/Quartz) to form ACHE/GA/β-NA/β-CD/C12SH/AuNP/APES/Quartz composite structure. The biosensor could recognise methylparathion pesticide with simple fabrication, and assembled material was permanently existed.3. Quantum dots(CdTe) and ACHE were alternately immobilized onto the quartz substrate to form ACHE biosensor based on SAMs. CdTe/APES/Quartz nanocomposite structure was modified with self-assembled monolayer of APES by aqueous phase silanization, giving a homogenous surface terminated with amino groups. CdTe were further assembled on this functionalized monolayer substrate to form CdTe/APES/Quartz nanocomposite structure. Via intermediate of chitosan with positive charge, CdTe and ACHE were assembled onto the self-assembled multilayer films by layer-by-layer assembly technique. Self-assembled multilayer films (CdTe/CS/ACHE/CS/CdTe/APES/Quartz) could be used to detect organophosphorus pesticide as low as 3.20×10-8 M with good regeneration, stability, and selectivity.4. The simulation of quantum chemistry (Gaussian03) had indicated that quantum chemical parameters of organophosphorus pesticides. The chemical model of selective inhibition of acetylcholinesterase to organophosphorus pesticides was also established. It would provide a theoretic direction for recognition of OPs in the environment.