Visualized monitoring of radioactive iodide ions in environment using electrochemiluminescence device through free radical annihilation mechanism

The monitoring of radioactive iodide ions in environment is an apparent challenge in the field of environmental radiochemistry. Herein, we report an efficient electrochemiluminescence (ECL) array detection device to achieve visualized rapid monitoring and accurate warning of trace radioactive iodide in the environment. In detail, we prepared conjugated polymer poly[(9,9-dioctylfuor-enyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1,3}-thiadiazole)] (PFBT) into polymer dots and modified it on ITO electrode to obtain an array ECL detection device, of which the ECL signal is quenched by iodide ions. This detection device gives a low limit of detection (17 ng/L) and an excellent selectivity to iodide ion, as well as realizing visualized rapid monitoring of trace iodide in natural water samples by using ECL imaging technology. A new iodide detection mechanism, free radical annihilation (FRA), is presented, which involves an ECL co-reactant reagent poisoning process by iodine free radical obtained on the surface of electrode and is further demonstrated by electrochemical experiments, DFT calculations and ESP analysis. This work provides an efficient strategy for the visualized, rapid and accurate monitoring and warning of trace radioactive iodide in water environment, showing significant meaningful prospects in the field of public security and health.