title: Carbon dots functionalized by organosilane with double-sided anchoring for nanomolar Hg2+ detection.
abstract: Surface functional groups on carbon dots (CDs) play a critical role in defining their photoluminescence properties and functionalities. A new kind of organosilane-functionalized CDs (OS-CDs) were formed by a low temperature (150°C) solvothermal synthesis of citric acid in N-(β-aminoethyl)-γ-aminopropylmethyl-dimethoxysilane (AEAPMS). Uniquely, the as-synthesized OS-CDs have dual long chain functional groups with both NH2 and Si(OCH3)3 as terminal moieties. Double sided anchoring of AEAPMS on CDs occurs, facilitated by the water produced (and confined at the interface between CDs and solvent) when citric acid condenses into the carbon core. The resultant OS-CDs are multi-solvent dispersible, and more significantly, they exhibit excellent selectivity and sensitivity to Hg(2+) with a linear detection range of 0-50 nM and detection limit of 1.35 nM. The sensitivity and selectivity to Hg(2+) is preserved in highly complex fluids with a detection limit of 1.7 nM in spiked 1 M NaCl solution and a detection limit of 50 nM in municipal wastewater effluent. The results show that the OS-CDs synthesised by the solvothermal method in AEAPMS may be used as an effective Hg(2+) sensor in practical situations.
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia; Environmental Engineering, Griffith University, Brisbane, QLD 4111, Australia; State Key Laboratory of Heavy Oil Processing Key Laboratory of CNPC, China University of Petroleum, Qingdao, China.
authors.forename: Wentai
authors.initials: W
authors.lastname: Wang
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia; Environmental Engineering, Griffith University, Brisbane, QLD 4111, Australia.
authors.forename: Tak
authors.initials: T
authors.lastname: Kim
authors.affiliation: State Key Laboratory of Heavy Oil Processing Key Laboratory of CNPC, China University of Petroleum, Qingdao, China.
authors.forename: Zifeng
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia.
authors.forename: Guangshan
authors.initials: G
authors.lastname: Zhu
authors.affiliation: CSIRO Materials Science and Engineering, Victoria, Australia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Cole
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia.
authors.forename: Nam-Trung
authors.initials: NT
authors.lastname: Nguyen
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia; Environmental Engineering, Griffith University, Brisbane, QLD 4111, Australia. Electronic address: qin.li@griffith.edu.au.
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
keywords: Carbon dots; Fluorescent nanoparticles; Hg(2+) detection; Water quality