title: Fe(3+)-functionalized carbon quantum dots: A facile preparation strategy and detection for ascorbic acid in rat brain microdialysates.
abstract: This study reports an Fe(3+)-functionalized carbon quantum dots (Fe(3+)-functionalized CQDs) for the highly sensitive and selective detection of ascorbic acid (AA) in rat brain microdialysates based on the specific redox reaction between iron(III) ions and AA. The carbon quantum dots (CQDs) were synthesized by one-step pyrolysis of a small organic molecules i.e. tris(hydroxymethyl)aminomethane (Tris). Fe(3+) can tightly chelate to the surface of CQDs by the hydroxyl group to form Fe(3+)-functionalized CQDs while the fluorescence of CQDs can be effectively quenched by Fe(3+) via Fluorescence resonance energy transfer (FRET). The fluorescence of the Fe(3+)-functionalized CQDs can be sensitively turned on by AA to give an "on-off-on" fluorescence response through the oxidation-reduction between Fe(3+) and AA since the produced Fe(2+) has much lower chelating ability to CQDs and the fluorescence of CQDs can be restored. This Fe(3+)-functionalized CQDs based nanoprobe shows high selective and sensitive response in the concentration of AA ranging from 0.1 μM to 50 μM with the detection limit as lower as 9.1 nM, which is lower than other assays. Finally, the proposed fluorescent probe was successfully applied to direct analysis of AA in biological fluids, i.e. rat brain microdialysates, and may pave a new route to the design of effective carbon quantum dots-based fluorescence probes for other bioassay.
authors.affiliation: College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China; Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Linbo
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Jingxuan
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Quanwei
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China.
authors.forename: Kangyu
authors.initials: K
authors.lastname: Liu
authors.affiliation: Capital University of Physical Education and Sports, Beijing 100191, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China.
authors.forename: Wenji
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. Electronic address: linyuqing@cnu.edu.cn.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Lin
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D000818:Animals; D001205:Ascorbic Acid / Q000032:analysis* / Q000737:chemistry; D001921:Brain / Q000166:cytology*; D002244:Carbon / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D057230:Limit of Detection; D017551:Microdialysis; D045663:Quantum Dots / Q000737:chemistry*; D051381:Rats
chemical_list: D002244:Carbon; D007501:Iron; D001205:Ascorbic Acid
keywords: Ascorbic acid; Brain microdialysate; Carbon quantum dots; Fluorescence; Iron(III) ion