Cane Molasses Graphene Quantum Dots Passivated by PEG Functionalization for Detection of Metal Ions

Ying Lou; Jianying Ji; Aimiao Qin; Lei Liao; Ziyuan Li; Shuoping Chen; Kaiyou Zhang; Jun Ou

doi:10.1021/acsomega.0c00098

Cane Molasses Graphene Quantum Dots Passivated by PEG Functionalization for Detection of Metal Ions

ACS Omega. 2020 Mar 3;5(12):6763-6772. doi: 10.1021/acsomega.0c00098. eCollection 2020 Mar 31.

Authors

Ying Lou¹, Jianying Ji¹, Aimiao Qin¹, Lei Liao², Ziyuan Li³, Shuoping Chen¹, Kaiyou Zhang¹, Jun Ou¹

Affiliations

¹ Key Lab New Processing Technology for Nonferrous Metals & Materials Ministry of Education, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, P. R. China.
² College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, P. R. China.
³ College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, P. R. China.

Abstract

Poly(ethylene glycol) passivated graphene quantum dots (PEG-GQDs) were synthesized based on a green and effective strategy of the hydrothermal treatment of cane molasses. The prepared PEG-GQDs, with an average size of 2.5 nm, exhibit a brighter blue fluorescence and a higher quantum yield (QY) (up to approximately 21.32%) than the QY of GQDs without surface passivation (QY = 10.44%). The PEG-GQDs can be used to detect and quantify paramagnetic transition-metal ions including Fe³⁺, Cu²⁺, Co²⁺, Ni²⁺, Pb²⁺, and Mn²⁺. In the case of ethylenediaminetetraacetic acid (EDTA) solution as a masking agent, Fe³⁺ ions can be well selectively determined in a transition-metal ion mixture, following the lowest limit of detection (LOD) of 5.77 μM. The quenching mechanism of Fe³⁺ on PEG-GQDs belongs to dynamic quenching. Furthermore, Fe³⁺ in human serum can be successfully detected by the PEG-GQDs, indicating that the green prepared PEG-GQDs can be applied as a promising candidate for the selective detection of Fe³⁺ in clinics.