Construction Of Electrochemical Sensor For Molecular Imprinted Acupuncture Needle And Its Application In The Detection Of Phenothiazines

Phenothiazines are one of the most widely used psychotropic drugs in the world.Due to the abuse of phenothiazines,their residues are often found in the ecological environment or edible animals,and then pose a potential threat to ecosystems and human health.Therefore,it is very important to establish a rapid and sensitive method for the determination of phenothiazines for human health and environmental monitoring.However,the substance is easy to be oxidized and affected by interference.Compared with other common electrodes,acupuncture needle electrode is small and simple,easy to be modified,and can be flexibly detected in real time.It is an ideal base for electrochemical sensors.However,due to its property of low electrocatalytic activity,it is difficult to detect most substances.To solve those problems,nanomaterials and molecular imprinting technology was introduced in the modification of acupuncture needle electrodes.In this dissertation,a bimetallic nanointerface was constructed on the surface of acupuncture needle to improve the conductivity and electrochemically active area of the electrode.At the same time,molecular-imprinted layer was constructed on the top of the above electrode to improve the selectivity of the electrode.The main work of this dissertation is as follows:1.Gold/copper nanoparticles(Au/Cu NPs)were first electrodeposited onto the acupuncture needle electrode(ANE)to increase its conductivity.Subsequently,3-aminophenylboric acid(3-APBA)and chlorpromazine(CPZ)was used as functional monomer and template molecule to fabricate surface molecularly imprinted biosensor via electropolymerization method.The obtained interface with imprinted cavity showed high selectivity and sensitive detection performance for CPZ after elution.Under optimum condition,the MIP/3-APBA/Au/Cu/ANE sensor exhibits outstanding performance for detecting CPZ with good linearity in the range of 0.1 μM～100 μM and100 μM～1000 μM,with a detection limit of 0.07 μM.The obtained biosensor has good selectivity,stability and repeatability.Furthermore,it is applied to detect chlorpromazine in human serum and environmental water.2.Gold/tin nanoparticles(Au/Sn NPs)were modified on the surface of acupuncture needle to construct Au/Sn/ANE electrode.It can greatly improve the electrical conductivity of bare acupuncture needle electrode and increase a large number of promethazine(PMZ)active centers.After that,o-phenylenediamine(OPD)and template molecule PMZ were simultaneously polymerized on Au/Sn/ANE electrode to form molecularly imprinted polymeric membrane by a simple electropolymerization method.The resulted MIP/OPD/Au/Sn/ANE electrode has excellent detection ability for phenothiazine promethazine.Under optimum condition,the MIP/OPD/Au/Sn/ANE sensor exhibits outstanding performance for detecting PMZ with good linearity in the range of 0.5 μM～500 μM,with a detection limit of 0.14 μM.The fabricated biosensor has the advantages of low detection limit and high sensitivity.In addition,the electrode shows strong anti-interference ability towards PMZ and is successfully applied to analyze PMZ in human serum and environmental water samples.