A novel, cost effective, sensitive and environmentally friendly approach using a physical mixture of carbon dots (CDs) and gold nanoparticles (AuNPs) is reported for the detection of cyanide ions (CN-) in water. We observed significant quenching of fluorescence of CDs by AuNPs and the restoration of fluorescence by the removal of AuNPs. A dual mode sensing approach for the estimation of CN- in water is carved out of this observation exploiting both the FRET between CDs and AuNPs and the well-known gold leaching by CN-. This technique does not involve any complex chemistry or any tedious synthetic routes and can be used for the sensing of cyanide in aqueous media. The method is sensitive up to a concentration of 1 mgL-1 (1 μg mL-1) of CN- in water and its presence/absence can also be visualized by naked eye by illuminating the solution using light at 365 nm.
Changerath R, Kunnatheery S and Roy Joseph