The fluorescence enhancement effect of the Tb-Gd-guanosine-5′-triphosphate-phen system and its analytical application

Abstract

It has been found that Tb³⁺ can react with guanosine-5′-triphosphate (GTP) and o-phenanthroline (phen), resulting in the intrinsic fluorescence of Tb³⁺. This fluorescence can be enhanced by adding La³⁺, Gd³⁺, Lu³⁺, Sc³⁺, Y³⁺, and so on, among which Gd³⁺ produces the greatest enhancement. These are new co-luminescence systems. The experiments indicate under optimum conditions, the fluorescence intensity of the Tb-Gd-GTP-phen system is proportional to the concentration of GTP over the range 1×10⁻⁹ to 3×10⁻⁵ mol/l. The detection limit is 3.1×10⁻¹⁰ mol/l. The proposed method provides the most sensitive fluorimetry of GTP so far. The mechanism of the Tb-Gd-GTP-phen system has also been studied. The data indicates that there is a large congeries of Tb-Gd-GTP-phen, and the fluorescence enhancement of the Tb-Gd-GTP-phen system is considered to originate from intramolecular and intermocular energy transfers, and the energy-insulating sheath of the Gd complex.