Study On Paper-based Electrochemiluminescence Sensor Based On Doped Graphene Quantum Dots

Nowadays,the problem of water environment pollution is becoming more and more serious.Heavy metal ions and phenolic pollutants in the water environment pose health hazards to people.In this paper,a paper-based electrode was developed by screen printing technology,and an electrochemiluminescence（ECL）sensor was constructed using a doped graphene quantum dot system to achieve sensitive detection of catechol（CC）and heavy metal copper ions,which provides a new idea for the detection of pollutants in the aqueous environment.The main studies are as follows.First,GQDs and N-GQDs were prepared by pyrolysis using citric acid and urea as precursors,and the ECL intensity and stability of the doped quantum dots were demonstrated to be enhanced by comparing the characterization of the two quantum dots with the ECL test results.The electronic and optical properties of the GQDs and N-GQDs were compared and analyzed using first-nature principle calculations to theoretically explain the reason for the increased ECL intensity of the doped quantum dots.The combination of N-GQDs/K₂S₂O₈with the ECL sensor accomplished a wider linear detection of copper ions in the range of 0.01-1000μM with recoveries ranging from 97.3%to 109.5%.The sensor method proposed in this experiment has good repeatability,stability,reliability,and selectivity.Secondly,N,S-GQDs were synthesized by pyrolysis using citric acid and L-cysteine as precursors.The N,S-GQDs were characterized in various ways and the successful doping of N and S elements was demonstrated.The linear detection of catechol in the range of 0.1-1000μM was accomplished by combining the prepared N,S-GQDs with paper-based electrodes with recoveries in the range of105.5%～108.9%.The sensor can be successfully applied to the determination of catechol in real samples,which is a convenient,reliable and sensitive detection method.