Electrochemical detection of copper ions with covalent organic frame material modified carbon paste electrode

The covalent organic framework material TpBD-COF was synthesized by solvothermal reaction， and characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. Then， COF-2-BPPF6-CPE was prepared by mixing TpBD-COF，carbon paste and ionic liquid ［BPPF6] in a certain proportion， and the electrochemical performance of the working electrode was evaluated by cyclic voltammetry (CV） and differential pulse voltammetry (DPV）. Copper ions can be sensitively responded on the modified electrode in a buffer solution of potassium hydrogen phthalate at pH 3.50. The results showed that the COF modified carbon paste electrode had higher peak current for copper ion， and the peak current was linearly related to the molar concentration of copper ion in the range of 1 to 200 μmol/L，with a linear correlation coefficient(R2） of 0.9997. The detection limit was 0.13 μmol/L. The modified electrode showed excellent selectivity， stability and reproducibility. The standard addition method was used for the determination of copper ions in water samples with recoveries in the range of 100.6%-101.2%. These results suggested that COF modified carbon paste electrodes can be applied to detect copper ions in water samples. © 2023 the authors.