title: Selective detection of Fe2+ by combination of CePO4:Tb3+ nanocrystal-H2O2 hybrid system with synchronous fluorescence scan technique.
abstract: A new method for quenching kinetic discrimination of Fe(2+) and Fe(3+), and sensitive detection of trace amount of Fe(2+) was developed by using synchronous fluorescence scan technique. The principle of this assay is based on the quenching kinetic discrimination of Fe(2+) and Fe(3+) in CePO(4):Tb(3+) nanocrytals-H(2)O(2) hybrid system and the Fenton reaction between Fe(2+) and H(2)O(2). Stable, water-soluble and well-dispersible CePO(4):Tb(3+) nanocrystals were synthesized in aqueous solutions, and characterized by transmission electron microscopy (TEM) and electron diffraction spectroscopy (EDS). We found that both Fe(2+) and Fe(3+) could quench the synchronous fluorescence of CePO(4):Tb(3+) nanocrytals-H(2)O(2) system, but their quenching kinetics velocities were quite different. In the presence of Fe(3+), the synchronous fluorescent intensity was unchanged after only one minute, but in the presence of Fe(2+), the synchronous fluorescent intensity decreased slowly until 28 min later. The Fenton reaction between Fe(2+) and H(2)O(2) resulted in hydroxyl radicals which effectively quenched the synchronous fluorescence of the CePO(4):Tb(3+) nanocrystals due to the oxidation of Ce(3+) into Ce(4+) by hydroxyl radicals. Under optimum conditions, the linear range for Fe(2+) is 3 nM-2 μM, and the limit of detection is 2.0 nM. The method was used to analyze water samples.
authors.affiliation: College of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Hongqi
authors.initials: H
authors.lastname: Chen
authors.forename: Jicun
authors.initials: J
authors.lastname: Ren
mesh_terms: D002138:Calibration; D002563:Cerium / Q000737:chemistry*; D005296:Ferrous Compounds / Q000032:analysis*; D005453:Fluorescence; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010710:Phosphates / Q000737:chemistry*; D013725:Terbium / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D010710:Phosphates; D013725:Terbium; D002563:Cerium; D006861:Hydrogen Peroxide; C048083:cerium phosphate