Nitrogen-doped graphene quantum dots based fluorescent probe for highly sensitive detection of thiosulfate anion and oxidative compounds

Owing to the huge threat to human health and environment from thiosulfate anion (S2O32- ) widely used in various fields, the development of an effective detection method for S2O32- is urgently desired. Herein, we developed an iodine (I2) mediated nitrogen-doped graphene quantum dots (I2-mediated N-GQDs) as a fluorescence ?off-on? probe for S2O32- by iodimetry reaction oriented strategy. Firstly, I2 interacted with N-GQDs to form non-fluorescent N-GQDs/I2 complex due to the inner filter effect (IFE). In the presence of S2O32-, the iodimetry reaction between I2 and S2O32- disintegrated N-GQDs/I2 complex and re-switched on the quenched photoluminscence of N-GQDs. The I2-mediated N-GQDs nanoprobe with a limit of detection down to 93 pM has been successfully used to sense S2O32- in biological fluids and living cells. Moreover, the I2-mediated N-GQDs/S2O32nanoplatform could further detect oxidative compounds such as hydrogen dioxide, dichromate, permanganate, iron ion (III), copper ion (II), and cerium ion (IV).

Automated summary

A novel iodine-mediated nitrogen-doped graphene quantum dots nanoprobe has been developed as a fluorescence "off-on" probe for detecting S2O32-. This nanoprobe has a high sensitivity with a limit of detection down to 93 pM and can also detect other oxidative compounds in addition to S2O32-.