Covalent organic framework as a novel electrochemical platform for highly sensitive and stable detection of lead.

A sensitive and selective TAPB-DMTP-COF (TAPB, 1,3,5-tris(4-aminophenyl)benzene; DMTP, 2,5-dimethoxyterephaldehyde; COF, covalent organic framework) modified carbon paste electrode was evaluated as a novel electrochemical sensor for the determination of lead in an aqueous medium. Lead was accumulated on the TAPB-DMTP-COF surface by the complexation with the amine groups, and detected by differential pulse anodic stripping voltammetry. Due to the distinct structure features of COF, the resulting sensor revealed a fast electron transfer rate and outstanding adsorption capacity for lead. The influence of various experimental parameters (the content of COF, pH of the electrolyte solution, accumulation potential, and accumulation time) on the peak current were investigated in the overall analysis procedure. Under optimum conditions, the method showed an excellent linearity to the concentration of lead in the range of 0.0050 to 2.0 μmol/L with a detection limit of 1.9 nmol/L, and the relative standard deviation was 3.1% for 0.50 μmol/L of lead (n = 11). This method not only displays the feasibility of COF based sensor for trace levels of metal ions detection but also broadens the scope of applications of COF based hybrid materials in electroanalytical chemistry.