Highly selective, rapid-functioning and sensitive fluorescent test paper based on graphene quantum dots for on-line detection of metal ions

Abstract

In this study, test papers based on N-doped graphene quantum dots and graphene quantum dots were designed and prepared. They exhibited a highly selective fluorescence quenching response to Hg(II) and Fe(III) in water for 3.0 s to 2.0 min, respectively. Furthermore, low detection limit (0.1 μM) of the test papers was obtained, which was lower than the toxic level of Hg(II) and Fe(III). Moreover, the concentration of metal ions in water was directly determined according to the quenching time of the fluorescent test paper observed by the naked eye. Therefore, a convenient paper sensor for the rapid, sensitive and selective detection of metal ions in water was developed, which was expected to be applied in the accurate detection and large-scale monitoring of heavy metal pollution in the environment.