The Fabrications And Applications Of The Novel Tetrabromobisphenol A Electrochemical Sensors

Tetrabromobisphenol A(TBBPA)is the most widely used brominated flame retardant(BFR)with nearly 60% of the total market share.In recent years,along with the heavy usage and wide spread application of TBBPA,the environmental problems caused by TBBPA have been paid more and more attentions.TBBPA were reported to be found in various environmental samples around the world,as well as in biological samples.It can also migrate into creatures through bioaccumulation due to its lipophilicity,environmental stability and poor degradability.Besides,TBBPA has a number of toxicities including endocrine disrupting effects,neurotoxicity,immunotoxicity,hepatotoxicity,nepatotoxicity and ototoxicity.Therefore,with the purpose of TBBPA management,development of a simple,fast,sensitive and reliable analytical method for TBBPA detection is of significant importance.Compared with traditional methods,the electrochemical method is widely employed in environmental monitoring owing to its merits including simple operation,high sensitivity,fast response,and without complex sample preparation process.However,the response of TBBPA is really poor at bare electrode due to the weak electron transfer between the TBBPA and the sensing interface.Therefore,the point of this study is to establish electrochemical sensors based on the cooperative sensitized effect between surfactants and nanomaterials for the sensitive detection of TBBPA.The thesis consists of the following two parts: Part Ι : A novel tetrabromobisphenol A electrochemical sensor based on zwitterionic surfactant modified acetylene black paste electrodeObjective: To fabricate an electrochemical sensor for the detection of tetrabromobisphenol A(TBBPA)based on acetylene black paste electrode(ABPE)modified with a zwitterionic surfactant.Methods: Firstly,the surface of ABPE was modified with a zwitterionic surfactant,3-(N,N-Dimethylpalmitylammonio)propanesulfonate(SB3-16),through hydrophobic interaction.Secondly,cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)were applied to characterize the modified electrode.Finally,CV was used to optimize the experiment conditions and the as-prepared sensor was employed to detect TBBPA in water samples.Results: The experimental results indicated that there was a synergistic effect between SB3-16 and AB.The introduce of SB3-16 and AB can not only increase the specific surface area of the modified electrode,but also enhance the conductivity of the modified electrode.Under the optimal experiment conditions,the peak currents of TBBPA were found to be linearly correlated with its concentrations in the range of 1 nM to 1 μM,with a detection limit of 0.4 nM(the ratio of signal to noise is 3).This sensor was also employed to detect TBBPA in water samples.The recoveries of the sensor were from 92.4% to 100.6%,which were consistent with the results acquired from HPLC.Conclusion: An electrochemical sensor for the determination of TBBPA was developed based on the cooperative sensitized effect between SB3-16 and AB.Due to the superior electrochemical properties of AB and good adsorption capacity of SB3-16,the electrochemical response of TBBPA was effectively enhanced on the modified electrode.Moreover,this sensor was successfully applied to detect TBBPA in water samples.Part II : A novel tetrabromobisphenol A electrochemical sensor based on a long alkyl chain thiol self-assembled monolayer on the gold nanoparticles modified glassy carbon electrodeObjective: To construct an electrochemical sensor consisting of dodecanethiol(DDT)self-assembled monolayer(SAM),gold nanoparticles and glassy carbon electrode(DDT-SAM/Au NPs/GCE),which was applied for the determination of TBBPA.Methods: Firstly,the gold nanoparticles(Au NPs)was electrodeposited on the surface of the glassy carbon electrode(GCE)through CV.Secondly,the prepared Au NPs/GCE was immersed in the solution of DDT.Via Au-S chemical bonding reaction,DDT was immobilized on the surface of Au NPs/GCE and then formed DDT –SAM.Finally,CV,EIS,SEM and AFM were utilized to character the DDT-SAM/Au NPs/GCE.Results: The results of SEM and AFM demonstrated that Au NPs and DDT were successfully immobilized on the surface of GCE.Electrochemical studies showed that the DDT-SAM/Au NPs/GCE could lower the oxidation overpotential and enhance the electrochemical response of TBBPA.Under the optimal experiment conditions,the oxidation peak current was proportional to the concentration of TBBPA over the range of 0.5 n M to 1 μM with a detection limit of 0.084 n M(the ratio of signal to noise is 3).The electrochemical sensor had been successfully applied to the determination of TBBPA in real samples.Moreover,the results of amperometric response further illustrated that this sensor might have a promising potential for on-site practical detections.Conclusion: An electrochemical sensor consisting of dodecanethiol(DDT)self-assembled monolayer,gold nanoparticles and the glassy carbon electrode(DDT-SAM/Au NPs/GCE)was constructed.The Au NPs had large specific surface area,which could provide more reactive sites.The hydrophobic DDT-SAM increased the absorption of TBBPA on the surface of the modified electrode by hydrophobic effect.Based on the cooperative sensitized effect between Au NPs and DDT-SAM,the sensitive detection of TBBPA was achieved.This sensor provided a new approach for the determination of TBBPA.