Application Of Chemical Sensors Based On Electro-polymerization In Drug Analysis

The continuous development of science and technology provides a variety of methods for the analysis and detection of chemical or biological compounds.At the same time,looking for a new detection technology has become the focus of many researchers.Due to the excellent characteristics of the sensor,such as easy operation,economical,sensitive,portable and easy to manufacture,people have been committed to the integration of electronic components and identification components to develop electrochemical sensors.Especially in recent decades this area has aroused widespread concern.Electrochemical sensors are widely used in the detection of chemical and biological target molecules,such as electrochemical impedance sensors,current sensors and photoelectrochemical luminescence sensors.The development of electrochemical sensors based on different polymer films is significant,and the biocompatibility,sensitivity and selectivity of the electrochemical sensors are improved by amplifying the electrochemical signals,which shows great potential in the analysis and determination.In this paper,three kinds of polymer-based electrochemical sensors were developed.A series of rapid,sensitive and stable quantitative analysis methods were established.The electrochemical behavior of common drugs such as adrenaline,barbital and dopamine was studied and analyzed.The main contents are as follows:(1)A new and effective AuNPs-Layered double hydroxides(LDHs)modified glassy carbon electrode(AuNPs/LDHs/GCE)has been prepared and was characterized by SEM and electrochemical methods.The electrochemical behavior of adrenaline(AD)is studied by cyclic voltammetry and differential pulse voltammetry at the modified electrode.Compared to the LDHs modified GCE without AuNPs film(LDH/GCE),the AuNPs/LDH/GCE exhibits remarkably higher catalytic activity for AD electro-oxidation.Under the optimal conditions,the oxidation peak current of adrenaline is linearly related to adrenaline concentration range of 9.00×10-8 mol/L to 1.00×10-4 mol/L(pH=7.00),and the low detection limit is 3.10×10-8 mol/L(at the signal-to-noise ratio of 3).This method was successfully applied for the adrenaline determination in commercial pharmaceutical injections of the quality control.(2)A molecularly imprinted electrochemical sensor was prepared based on poly folic acid(PFA)for rapid detection of barbital(BAR).The PFA membrane was obtained via directly electropolymerization technique on the surface of chemically modified gold electrode(Au/CME)by means of cyclic voltammetry(CV)in the potential range between-0.4 and 1.0 V in phosphate buffer solution(PBS)pH 7.04.And the molecularly imprinted polymers(MIP)membrane were synthesized with BAR as template molecules and FA as the functional monomer.The performance and surface feature of the proposed imprinted sensor were investigated using cyclic voltammetry(CV),differential pulse voltammetry(DPV),electrochemical impedance spectroscopy(EIS)and scanning electron microscope(SEM).Under the optimized conditions,the peak current decrease(?Ip)was proportional to the BAR concentration in the range of 1.00×10-7~1.00×10-4 mol/L(R2=0.9982)with a detection limit(S/N=3)of 4.65×10-8 mol/L.The results indicated that the imprinted sensor exhibited an excellent selectivity for BAR and it was successfully used to determine BAR in real samples with recoveries of 94.7% ~106.2% by using the standard addition method.(3)A novel AuNPs-functionalized molecular imprinted polymers A novel electrochemical sensor to detect dopamine was constructed using by polymerizing cetyltrimethyl ammonium bromide(CTAB)onto glassy carbon electrode(GCE)by cyclic voltammetry,and then applying copper oxide nanowires to CTAB polymer film.The fabrication process of the sensor was characterized by cyclic voltammetry,and its electrochemical behaviour was studied by cyclic voltammetry and differential pulse voltammetry.The experimental results showed that compared with the bare Au electrode,the poly(CTAB)/CuONW/GCE electrode displayed excellent electrochemical activity towards dopamine,and the anodic peak current increased linearly with the increasing concentration of dopamine from 5.00×10-8 to 1.00×10-5 mol/L with a low detection limit of 1.20×10-8 mol/L(S/N=3).The recovery of the sample was 96.38 ~ 103.92%.The sensor possesses high sensitivity,strong anti-interference ability and good stability,and can be used for the analysis of dopamine in practical samples.