Quantum dots attached to graphene oxide for sensitive detection of ascorbic acid in aqueous solutions.

Water-soluble fluorescent carboxyl-functionalized CdSe-ZnS quantum dots (QDs) were immobilized on graphene oxide (GO) and used for sensitive detection of ascorbic acid in aqueous solutions. QDs were attached to the surface of graphene oxide using the EDC/NHS-sulfo coupling reaction. Ascorbic acid is known as an antioxidant. It plays a crucial role in health maintenance, bio synthetic pathways such as formation of collagen and regulates immune system. The photoluminescence (PL) intensity of as-prepared GO-QD hybrids in water was quenched by ascorbic acid at ambient temperature. Based on this photoluminescence quenching phenomenon, a simple, rapid, and sensitive procedure is developed. In this study we are successful in detecting ascorbic acid due to its biological significance and the limit of detection is 568 pM.