摘要
The phenomenon of fluorescence enhancement for the system of terbium( Ⅲ ) with trimesic acid [ ben-zene-1, 3, 5-tricarboxylic acid (TMA)] in the presence of an excase of La￣(3+) in gelatin aqusous solution wasstudied. The fluorescence intensity of Tb￣Ⅲ -TMA system can be greatly increased by La￣(3+) , which causedthe largest enhancement of the fluorescence intensity over two orders of magnitude. The intermolecular transfer of energy was responsible for the mechanism of the fluorascence enhancement. Gelatin plays animportant role for the stabilization of the system. The system, having the maximum excitation and emis-sion wavelengths at 260 nm and 549 nm, respectively, shows a constant fluorescence interisity over the pHrange 4～6. The fluorescence intensity is a linear function of Tb￣(3+) concentration in the range of 8. 0 ×10 ￣(-9)～ 2. 6 × 10￣(-7) mol· L￣(-1) and the limit of detection is 2.0 × 10￣(-9) mol·L￣(-1) . The optimized procedurewas used for the determination of trace amount of terbium in rare earth oxides and international standardreference rocks with satisfactory results.
The phenomenon of fluorescence enhancement for the system of terbium( Ⅲ ) with trimesic acid [ ben-zene-1, 3, 5-tricarboxylic acid (TMA)] in the presence of an excase of La￣(3+) in gelatin aqusous solution wasstudied. The fluorescence intensity of Tb￣Ⅲ -TMA system can be greatly increased by La￣(3+) , which causedthe largest enhancement of the fluorescence intensity over two orders of magnitude. The intermolecular transfer of energy was responsible for the mechanism of the fluorascence enhancement. Gelatin plays animportant role for the stabilization of the system. The system, having the maximum excitation and emis-sion wavelengths at 260 nm and 549 nm, respectively, shows a constant fluorescence interisity over the pHrange 4～6. The fluorescence intensity is a linear function of Tb￣(3+) concentration in the range of 8. 0 ×10 ￣(-9)～ 2. 6 × 10￣(-7) mol· L￣(-1) and the limit of detection is 2.0 × 10￣(-9) mol·L￣(-1) . The optimized procedurewas used for the determination of trace amount of terbium in rare earth oxides and international standardreference rocks with satisfactory results.
