Electrochemical Analysis And Application Of COFs Material Modified Electrode

Environmental pollutants in water have serious harmfulness,so more and more attention has been paid to them.Electrochemical analysis has the advantages of high sensitivity,good stability and repeatability,as well as short analysis time,and can provide a platform for detecting environmental pollutants in water such as heavy metals,pathogenic microorganisms and newborn pollutants（medicine）.Differential pulsed anode stripping voltammetry is a highly sensitive electrochemical analysis method,which can be applied to the detection of heavy metal ions.Imine COFs（Covalent Organic Frameworks,COFs）have high porosity and specific surface area and high chemical stability.It can coordinate with metals and bind firmly.The reason is that on the one hand,it can be used as adsorbent for metal ions throughπ-πaccumulation and hydrogen bond interaction.On the other hand,its imine structure contains abundant N atoms,providing sufficient active sites for coordination with metals.Because COFs material evenly dispersed in the water is not easy to maintain,if use the traditional COFs materials fluorescence analysis,there is no system to assess COFs materials in the water of the sensing performance of quantitative data,so we will imine COFs material made from modified electrodes to avoid this weakness,so as to realize COFs material detection of heavy metal ions in aqueous solution.In this paper,three different imidyl COFs（Tp Pa-2 with two methyl monomers,Tp BD with benzidine monomer structure and TpTh with hydrazide monomer structure）were first used to prepare modified electrodes for the detection of copper ions and mercury ions by differential pulsed stripping voltammetry.The method has the advantages of green,fast and easy to operate.The experimental results are as follows:（1）Tp Pa-2/Nafion modified electrode was used to detect Cu²⁺ions.The linear range was1.0×10^-6M～1.0×10^-3M,R²=0.9836,and the LOD was 5.0×10^-7M;The linear range of Hg²⁺detection was 1.0×10^-7M～1.0×10^-3M,R²=0.9945,and the LOD was 1.0×10^-7M.In the test of tap water samples,the recoveries ranged from 98%to 103.3%,RSD was less than 3%.（2）Tp BD/Nafion modified electrode was used to detect Cu²⁺ions.The linear range was5.0×10^-7M～1.0×10^-4M,R²=0.994,and the LOD was 2.0×10^-7M;The linear range of Hg²⁺detection was 1.0×10^-6M～1.0×10^-4M,R²=0.9721,and the LOD was 5.0×10^-7M.In the test of tap water samples,the recoveries ranged from 101.8%to 110.4%,RSD was less than 9.7%.（3）TpTh/Nafion modified electrode was used to detect Cu²⁺ions.The linear range was5.0×10^-6M～1.0×10^-4M,R²=0.9053,and the LOD was 5.0×10^-7M;The linear range of Hg²⁺detection was 5.0×10^-7M～1.0×10^-4M,R²=0.9915,and the LOD was 5.0×10^-7M.In the test of tap water samples,the recoveries ranged from 89.8%to 116.8%,RSD was less than 6.4%.