Establishment Of Novel Molecularly Imprinted Electrochemical Sensors And Its Analytical Study Of Tetrabromobisphenl A In The Environment

Currently,Tetrabromobisphenol A?TBBPA?is the most widely used brominated flame retardant,which can effectively improve the flammability of the product?e.g.textiles and plastic products?.However,various studies have found that there was residual TBBPA in water,dust,serum and breast milk.This organic pollutant with a stable chemical structure threatened the health of the human body in a certain extent:affecting the human reproductive system and nervous system and cause some pathological changes.Therefore,how to efficiently detect TBBPA in environment has become a very valuable research topic.Molecularly imprinted polymers?MIPs?are highly selective to specific targets.Also,electrochemical sensors are highly sensitive to current changes.In this paper,MIPs were introduced into electrochemical sensors which makes the prepared sensors have the advantages of high selectivity and high sensitivity.In recent years,molecularly imprinted electrochemical sensors have attracted much attention.It has successfully detected a variety of different types of environmental pollutants.Therefore,this kind of sensor has great potential to be used to detect the residues of specific pollutants in complex systems.In this dissertation,three novel electrochemical sensors were prepared based on MIPs and three nanomaterials,namely dendritic silver Nano-dendrites?AgNDs?,reduced graphite oxide/silver Nano-dendrites?rGO/AgNDs?and gold nanoparticles?AuNPs?for the detection of TBBPA in environment.The details are as follows?1?.An electrochemical sensor based on silver Nano-dendrites?AgNDs?and MIPs was used to detect TBBPA in environmental water.Firstly,AgNDs were modified on the surface of glassy carbon electrode?GCE?using potentiostatic deposition:7,7,8,8-tetracyano-p-quinone dimethane?TCNQ?as template.AgNDs can greatly improve the conductivity of GCE and provide a large number of deposition sites for MIPs.Subsequently,MIPs were synthesized on AgNDs/TCNQ/GCE surface by electro-polymerization using TBBPA and pyrrole.MIPs synthesized via electro-polymerization can be firmly attached to the surface of GCE and were easy to store and transport.Under the optimum conditions,the sensor has excellent linear relationship with TBBPA in the concentration range of 1.0×10^-6 mol L^-1 to 5.0×10^-9 mol L^-1 with a limit of detection?LOD?of 2.54×10^-10 mol L^-1?S/N=3?.The sensor has successfully detected three kinds of environmental water samples with recovery of 97.2-107.2%and relative standard deviation?RSD?of 3.00-7.98%.?2?.An electrochemical sensor based on reduced graphene oxide and silver Nano-dendrites?rGO/AgNDs?composite and MIPs was used to detect TBBPA in plastic products.First,AgNDs and rGO were modified on the surface of GCE through cyclic voltammetry?CV?.AgNDs/rGO composites can effectively improve the performance of GCE while rGO can prevent AgNDs falling off from GCE.Subsequently,MIPs were deposited on the modified electrode using CV.The specificity of MIPs can effectively improve the resistance of electrochemical sensors to complex environments.The performance of the sensor for TBBPA detection is as follows:detection range is 5×10^-11 mol L^-1 to 2×10^-8 mol L^-1 and LOD is 1.5×10^-11 mol L^-1?S/N=3?.In selectivity analysis,only tetrabromobisphenol S and bisphenol A can cause slight interference to the sensor.Finally,the TBBPA content in plastic water bottle(1.484?g g^-1)and phone case(56.00?g g^-1)were successfully detected by the prepared sensor and there was no significant deviation when compared to the results of LC-MS.?3?.Based on MIPs?BiM?@gold nanoparticles?AuNPs?,an electrochemical sensor with high selectivity for TBBPA was prepared.Firstly,MIPs?BiM?were synthesized on AuNPs using graft copolymerization:toluene acrylic acid?MAA?and 4-aminophenylthiophenol?4-ATP?as bifunctional monomers.Bifunctional monomers can provide MIPs with more different molecular ordering,thus effectively improving the selectivity and specificity of MIPs.In addition,the-SH at one end of 4-ATP can bind to AuNPs via Au-S bond while-OH groups at the other end can bind to TBBPA via hydrogen bond to form stable AuNPs/4-ATP/TBBPA complexes.Differential pulse voltammetry?DPV?was used to analyze the performance of the sensor for TBBPA.The detection range was 1.0×10^-7 mol L^-1 to 1.0×10^-5 mol L^-1 and the LOD was 4.8×10^-8 mol L^-1?S/N=3?.In selectivity analysis,none of the six TBBPA structural analogues can affect the detection of the sensor.Finally,the sensor has been successfully applied to the detection of TBBPA in three environmental waters with a reproducibility of 96.8-105.6%and a RSD of 4.4-6.1%.