Preparetion Of Two Types Of Polymer Film Modified Electrodes Based On Poly-citrazinic Acid And Poly B-eriochrome Red And Its Application In Electrocatalysis Of Small Biomolecules

The chemically modified electrode (CME) is an active research topic in the field ofelectrochemistry and electroanalytical chemistry. It has been widely used in analyticalscience, neurophysiology, environmental science, material science and1ife science.Present study indicates that fabricated a novel CME is very important to build sensinginterface with high sensitivity and selectivity. Several small biomolecules have beenstudied in this work based on two types of polymer film modified electrode. Theelectrode was prepared by electro-polymerization method and applied to study thecatecholamine neurotransmitter of dopamine (DA) and epinephrine (EP).Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM)and have been employed to characterize the surface features of the modified electrodes.Besides, the interference of uric acid (UA), ascorbic acid (AA) and acetaminophen(APA) to target analytes have also been discussed. The main points of this work arepresented as follows:1. A poly-citrazinic acid modified carbon paste electrode (PCA/CPE) was preparedby electropolymerization method. Firstly, the electrocatalytic oxidation process of DAand UA at the modified electrode has been studied. The result indicated that thePCA/CPE has excellent electrocatalytic activity to the oxidation of DA and UA. Aquasi-reversible redox peak was obtained by cyclic voltammetry (CV). The oxidationpeak currents and concentration of DA exhibited a good linearity relationship in therange of3.70×107~8.20×105mol· L1and1.04×104~9.34×104mol· L1with adetection limit (S/N=3) of1×107mol·L1. The oxidation peak current of DA and UAcan be obviously separated. Furthermore, the PCA/CPE has been used to the determination of EP, the linear calibration curves over the concentration range4.00×107~4.00×104mol·L1with a detection limit of2×107mol·L1can also beobtained. Finally, the proposed modified electrode was successfully applied for thedetection of DA, UA and EP in real pharmaceutical formulations..2. A poly B-eriochrome red chemically modified carbon paste electrode(PERB/CPE) was successfully constructed. The catalytic oxidation performance of DAand APA at PERB/CPE was carefully studied. The linear calibration curves over theconcentration range4.00×107~1.70×104mol·L1and2.20×104~1.30×103mol·L1forDA and1.70×106~1.20×103mol·L1for APA, respectively. The result shows that lowdetection limits of2×107mol·L1for DA and5×107mol·L1for APA, respectively. Inaddition, the sensor exhibits good selectivity toward selective determination of DA andUA. The results indicate that the proposed sensor has high electrocatalytic activity,sensitivity and selectivity. Besides, PERB/CPE was applied to detect EP, the anodicpeak currents and the concentration had a linear relationship in the range of5.00×107~2.78×104mol·L1with a detection limit of2×107mol·L1. The resultsindicated that the modified electrode can obviously accelerate the electron transfer rateand then promote the electrocatalytic oxidation of EP with broad detection range andlow detection limit. Finally, the proposed sensor was used to the determination of DAand EP in injection samples.