(494h) Carbon Dots-Based Sensors in Detection of Heavy Metals and PFAS

Carbon quantum dots (CQDs) are carbon nanoparticles with an average size of 5 nm or smaller that emit superior fluorescence. CQDs show great potential to replace traditional semiconductive counterparts as the next generation of fluorescent probes. With rich surface functional groups, CQDs can selectively conjugate with certain molecules such as heavy metal ions and small polyfluorinated substances (PFAS), resulting in the intensity quenching of the fluorescence signal. In this project, CQDs of different types were synthesized using bottom-up hydrothermal and solvothermal methods from different precursors to receive products that are rich in certain functional groups. CQDs were then introduced to solutions of either lead (II) ions and/or perfluorooctanoic acid (PFOA) with a concentration of pM- μM ranges. Under optimized conditions, the quenching effect of CQDs with solvothermal synthesis was found a linear relationship against the concentration of Pb2+ from 0.4-60 μg/L and a detection limit of 0.12 μg/L in aqueous solution. The hydrothermally synthesized CQDs are more effective in detecting PFOA with a broad concentration range. Our results demonstrate that CQDs could provide quick and accurate measurement of trace amounts of f heavy metal ions and PFOAs in polluted water, which provides residences a convenient way to monitor water contamination of these toxins to reduce health risks for communities.