A novel photoluminescence sensing system sensitive for and selective to bromate anions based on carbon dots

A sensitive and selective chemosensing system for bromate anions (BrO3− anions) is highly demand due to the serious toxicity of BrO3− anions. In this report, polymeric ethylene imine (PEI) functionalized photoluminescent carbon dots (CDs@PEI) were prepared by the thermal pyrolysis of citric acid and PEI. The as-prepared CDs@PEI were successfully employed to establish a photoluminescence (PL)-based sensing system for BrO3− anions with high sensitivity and selectivity. The experimental conditions were systemically optimized, and a linear relationship between the PL quenching rate of the CDs@PEI and BrO3− anion concentration in the range from 0.04 to 0.35 μM could be obtained, with a very low limit of detection of ca. 0.17 nM. The proposed method was further employed to determine BrO3− anions in drinking water, bottled water and lake water samples with good recoveries. This established method was also successfully employed to detect BrO3− anion content in practical pastry samples.