title: Self-assembly of graphene oxide with a silyl-appended spiropyran dye for rapid and sensitive colorimetric detection of fluoride ions.
abstract: Fluoride ion (F(-)), the smallest anion, exhibits considerable significance in a wide range of environmental and biochemical processes. To address the two fundamental and unsolved issues of current F(-) sensors based on the specific chemical reaction (i.e., the long response time and low sensitivity) and as a part of our ongoing interest in the spiropyran sensor design, we reported here a new F(-) sensing approach that, via assembly of a F(-)-specific silyl-appended spiropyran dye with graphene oxide (GO), allows rapid and sensitive detection of F(-) in aqueous solution. 6-(tert-Butyldimethylsilyloxy)-1',3',3'-trimethylspiro [chromene- 2,2'-indoline] (SPS), a spiropyran-based silylated dye with a unique reaction activity for F(-), was designed and synthesized. The nucleophilic substitution reaction between SPS and F(-) triggers cleavage of the Si-O bond to promote the closed spiropyran to convert to its opened merocyanine form, leading to the color changing from colorless to orange-yellow with good selectivity over other anions. With the aid of GO, the response time of SPS for F(-) was shortened from 180 to 30 min, and the detection limit was lowered more than 1 order of magnitude compared to the free SPS. Furthermore, due to the protective effect of nanomaterials, the SPS/GO nanocomposite can function in a complex biological environment. The SPS/GO nanocomposite was characterized by XPS and AFM, etc., and the mechanism for sensing F(-) was studied by (1)H NMR and ESI-MS. Finally, this SPS/GO nanocomposite was successfully applied to monitoring F(-) in the serum.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University , Changsha 410082, China.
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Duan
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhao
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Ronghua
authors.initials: R
authors.lastname: Yang
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods; D005459:Fluorides / Q000032:analysis*; D006108:Graphite / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D049408:Luminescent Agents / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009574:Nitro Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D001578:Benzopyrans; D007211:Indoles; D049408:Luminescent Agents; D009574:Nitro Compounds; D010087:Oxides; C088184:spiropyran; D006108:Graphite; D005459:Fluorides