Selective sensing of curcumin using L-cysteine derived blue luminescent graphene quantum dots

Abstract L-cysteine, a natural amino acid, was used to prepare Graphene quantum dots (GQDs) by the bottom-up approach in a one-step direct carbonization. The morphology and the fluorescent behaviour of the prepared GQDs were analyzed. Selective fluorescence-based sensing of curcumin was demonstrated using the prepared GQDs. The sensing was found to be independent of the pH of GQDs and the curcumin was detected even in its degraded form in the alkaline media. Secondary inner filter effects explicate the sensing of curcumin by the GQDs. A static cum dynamic quenching in the fluorescent intensity of GQDs was observed upon addition of curcumin. Curcumin sensing was found to be selective among a number of biomolecules and metal ions.