Graphitic carbon quantum dots as a fluorescent sensing platform for highly efficient detection of Fe3+ ions

Abstract

Reported here is a green synthesis of graphitic carbon quantum dots (GCQDs) as a fluorescent sensing platform for the highly sensitive and selective detection of Fe 3+ ions. Through the electrochemical ablation of graphite electrodes in ultrapure water, uniform GCQDs with graphitic crystallinity and oxygen containing groups on their surfaces have been successfully prepared. The absence of acid, alkali, salt and organic compounds in the starting materials effectively avoids complex purification procedures and environmental contamination, leading to a green and sustainable synthesis of GCQDs. The oxygen functional groups (e.g., hydroxyl, carboxyl) contribute to the water solubility and strong interaction with metal ions, which enable the GCQDs to serve as a fluorescent probe for the highly sensitive and selective detection of Fe 3+ ions with a detection limit as low as 2 nM. The high sensitivity of our GCQDs could be attributed to the formation of complexes between Fe 3+ ions and the phenolic hydroxyls of GCQDs. The fluorescence lifetime of GCQDs in the presence and absence of Fe 3+ was tested by time-correlated singlephoton counting (TCSPC), which confirmed a dynamic fluorescence quenching mechanism.

Graphene Quantum Dot Embedded Hydrogel for Dissolved Iron Sensing

“…Noteworthy responses for GQDs in solution were also seen for CuSO 4 and HgCl 2 with 13.9% and 18.1% decreases in fluorescence respectively. The response of GQDs to iron, copper and mercury has been extensively reported, it is therefore not surprising that a response was observed for Cu and Hg in this case –. A lesser response to Pb(NO 3 ) 2 , Al(NO 3 ) 3 and MgSO 4 was also seen.…”

“…The components for measuring GQD's response to iron are far less complicated than AAS and may also be miniaturised for portable use. To date however, GQD‐based ion sensing platforms have primarily been solution‐based assays . A preferable method for field analysis is a solid or pseudo‐solid‐state GQD sensing platform that requires minimal reagents and handling.…”

One Step Green Synthesis of Carbon Quantum Dots and Its Application Towards the Bioelectroanalytical and Biolabeling Studies

“…Carbon quantum dots gained greater acceptance because of their wide application for instance in bioimaging [18,19], nanomedicine [20,21], photocatalysis [22,23], electrocatalysis [24,25], biosensing [26,27], and chemical sensing [28,29]. It was also used as Hg 2+ , Cu 2+ , Fe 3+ , Pb 2+ and Ag + sensors [30][31][32][33][34]. These dots were also reported with its application as pH sensors by Jia et al [35].…”

Facile synthesis of N-rich carbon quantum dots from porphyrins as efficient probes for bioimaging and biosensing in living cells

“…The significantly reduced lifetime indicates the occurrence of dynamic quenching and confirms that the electron transfer between Fe 3+ and CQDs contributes to the fluorescence quenching. 43,49 …”