title: Insights into the recognition of dimethomorph by disulfide bridged β-cyclodextrin and its high selective fluorescence sensing based on indicator displacement assay.
abstract: In this work, the molecular recognition of dimethomorph by disulfide bridged β-cyclodextrin (SS-β-CD) was studied by UV spectroscopy,2D NMR, and molecular modeling. The results indicated that the SS-β-CD/dimethomorph was more stable than β-CD/dimethomorph, which is ascribed to the fact that the disulfide chain plays an important role in stabilizing the appropriate dual-CD conformation and also promoting the inclusion of the host and guest. In addition, a robust fluorescence method for dimethomorph sensing has been developed based on competitive host-guest interaction by selecting safranine T (ST) as optical indicator and SS-β-CD functionalized reduced graphene oxide (SS-β-CD-RGO) as the receptor. Upon the presence of dimethomorph to the pre-formed SS-β-CD-RGO·ST complex, the ST molecule is displaced by dimethomorph, leading to a "switch-on" fluorescence response. That is due to the fact that the binding constant of the dimethomorph/SS-β-CD complex was more than 5 times greater than that of ST/SS-β-CD. The fluorescence intensity of SS-β-CD-RGO·ST complex increased linearly with increasing concentration of dimethomorph ranging from 0.50 to 20.0μM. The proposed method showed a detection limit of 0.11μM for dimethomorph, and was successfully applied for the determination of dimethomorph residues in vegetables (cabbage, spinach) and environmental samples (water, soil) with good precision and recoveries from 96.5% to 104%.
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Yucong
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Yanqiong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Ye
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Genfu
authors.initials: G
authors.lastname: Zhao
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ran
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China. Electronic address: lcppp1974@sina.com.
authors.forename: Can-Peng
authors.initials: CP
authors.lastname: Li
mesh_terms: D004396:Coloring Agents / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005618:Fresh Water / Q000032:analysis; D057230:Limit of Detection; D008958:Models, Molecular; D009025:Morpholines / Q000032:analysis*; D010619:Phenazines / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D014675:Vegetables / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D004220:Disulfides; D004785:Environmental Pollutants; D009025:Morpholines; D010619:Phenazines; D012987:Soil; D047392:beta-Cyclodextrins; C076154:dimethomorph; C009195:safranine T
keywords: Dimethomorph; Disulfide bridged β-cyclodextrin; Fluorescence; Graphene; Indicator displacement assay