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

It has been found that Tb(3+) can react with guanosine-5'-triphosphate (GTP) and o-phenanthroline (phen), resulting in the intrinsic fluorescence of Tb(3+). This fluorescence can be enhanced by adding La(3+), Gd(3+), Lu(3+), Sc(3+), Y(3+), and so on, among which Gd(3+) 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 1x10(-9) to 3x10(-5) mol/l. The detection limit is 3.1x10(-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.