An electrochemiluminescence sensor for bromate assay based on a new cationic polythiophene derivative

A sensitive electrochemiluminescence (ECL) sensor was fabricated for bromate assay based on a cationic polythiophene derivative, poly[3-(1,1'-dimethyl-4-piperidinemethylene)thiophene-2,5-diyl chloride] (PTh-D)/nafion modified Au electrode. Bromate was used as the coreactant as well as detecting analyte in the ECL sensor for the first time. The prepared PTh-D exhibited excellent solubility, strong and stable cathodic ECL activity. PTh-D can be immobilized on the surface of Au electrode via AuS bonding and nafion and chitosan were also used to immobilize PTh-D. The fabricated sensor exhibited a good linear relationship between the ECL intensities and the concentrations of BrO3(-) ranging from 1 μM to 0.1 M with a detection limit of 1 μM. This proposed method not only expands the application of PTh-D, but also opens new doors toward the detection of BrO3(-).