title: Application of gold nanoparticles to spectrophotometric sensing of hydrophilic anions based on molecular recognition by urea derivative.
abstract: We have prepared gold nanoparticles (GNPs) modified with a thiol compound that possesses a phenylurea moiety for the spectrophotometric sensing of hydrophilic anions, such as dihydrogen phosphate, based on changes in the surface plasmon absorption of the GNP. We examined the spectral change of phenylurea-modified GNP in dichloromethane upon the addition of various anions as tetrabutylammonium salts to the solution. The GNP showed increasing plasmon intensity with the concentration of dihydrogen phosphate. For a control experiment with an inactive hexanethiolate-modified GNP, such an ion-selective change in the plasmon band was not observed. Furthermore, in order to realize the spectrophotometric detection of hydrophilic anions in water using GNP with the urea functionality, we attempted to prepare bifunctional GNP modified with both the phenylurea derivative and a water-soluble thiol (e.g., L-cysteine). The resulting bifunctional GNP showed anion-selective changes in the plasmon band accompanied by increasing absorbance at a longer wavelength due to GNPs aggregation.
authors.affiliation: Department of Applied Chemistry, Faculty of Systems Engineering, Wakayama University, Japan.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Kado
authors.forename: Ayumi
authors.initials: A
authors.lastname: Furui
authors.forename: Yu
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Nakahara
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kimura
mesh_terms: D000042:Absorption; D000838:Anions / Q000032:analysis* / Q000737:chemistry*; D001665:Binding Sites; D003545:Cysteine / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D053768:Metal Nanoparticles / Q000737:chemistry*; D008752:Methylene Chloride / Q000737:chemistry; D010671:Phenylurea Compounds / Q000737:chemistry*; D010710:Phosphates / Q000032:analysis / Q000737:chemistry; D012995:Solubility; D013053:Spectrophotometry / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000838:Anions; D010671:Phenylurea Compounds; D010710:Phosphates; D013438:Sulfhydryl Compounds; D014867:Water; D008752:Methylene Chloride; D006046:Gold; D003545:Cysteine