Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots
Erica Ciotta,
Stefano Paoloni,
Maria Richetta,
Paolo Prosposito,
Pietro Tagliatesta,
Chiara Lorecchio,
Iole Venditti,
Ilaria Fratoddi,
Stefano Casciardi,
Roberto Pizzoferrato
Affiliations
Erica Ciotta
Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy
Stefano Paoloni
Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy
Maria Richetta
Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy
Paolo Prosposito
Department of Industrial Engineering INSTM and CiMER, University of Rome Tor Vergata, 00133 Rome, Italy
Pietro Tagliatesta
Department of Chemical Sciences and Technology, University of Rome Tor Vergata, 00133 Rome, Italy
Chiara Lorecchio
Department of Chemical Sciences and Technology, University of Rome Tor Vergata, 00133 Rome, Italy
Iole Venditti
Department of Chemistry, University of Rome Sapienza, 00187 Rome, Italy
Ilaria Fratoddi
Department of Chemistry, University of Rome Sapienza, 00187 Rome, Italy
Stefano Casciardi
National Institute for Insurance against Accidents at Work (INAIL), Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, 00078 Monte Porzio Catone, 00133 Rome, Italy
Roberto Pizzoferrato
Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy
A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu2+, Pb2+ and As(III) was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements and transmission electron microscope (TEM) images we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III) and the formation of precipitate with Pb2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor.
