title: Manipulating the Surface Chemistry of Quantum Dots for Sensitive Ratiometric Fluorescence Detection of Sulfur Dioxide.
abstract: Herein, we report a novel approach to the rapid visual detection of gaseous sulfur dioxide (SO2) by manipulating the surface chemistry of 3-aminopropyltriethoxysilane (APTS)-modified quantum dots (QDs) using fluorescent coumarin-3-carboxylic acid (CCA) for specific reaction with SO2. The CCA molecules are attached to the surface amino groups of the QDs through electrostatic attraction, thus the fluorescence of CCA is greatly suppressed because of the formation of an ion-pair complex between the ATPS-modified QDs and CCA. Such an interaction is vulnerable to SO2 because SO2 can readily react with surface amino groups to form strong charge-transfer complexes and subsequently release the strongly fluorescent CCA molecules. The mechanism has been carefully verified through a series of control experiments. Upon exposure to different amounts of SO2, the fluorescent color of the nanoparticle-based sensor displays continuously changes from red to blue. Most importantly, the approach owns high selectivity for SO2 and a tolerance of interference, which enables the sensor to detect SO2 in a practical application. Using this fluorescence-based sensing method, we have achieved a visual detection limit of 6 ppb for gaseous SO2.
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Li
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Houjuan
authors.initials: H
authors.lastname: Zhu
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Mingtai
authors.initials: M
authors.lastname: Sun
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Yehan
authors.initials: Y
authors.lastname: Yan
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Zhang
authors.affiliation: §Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore.
authors.forename: Dejian
authors.initials: D
authors.lastname: Huang
authors.affiliation: †Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Suhua
authors.initials: S
authors.lastname: Wang
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D015394:Molecular Structure; D011437:Propylamines; D045663:Quantum Dots; D012821:Silanes / Q000737:chemistry*; D013458:Sulfur Dioxide / Q000032:analysis*; D013499:Surface Properties
chemical_list: D003374:Coumarins; D005456:Fluorescent Dyes; D011437:Propylamines; D012821:Silanes; D013458:Sulfur Dioxide; C477625:amino-propyl-triethoxysilane; C104227:coumarin-3-carboxylic acid