The fluorescence enhancement effect of Tb–Gd–adenosine triphosphate–phen system and its analytical application

It is found that the fluorescence of Tb–adenosine triphosphate (ATP)–phenanthroline (phen) system can be enhanced by Gd3+. The fluorescence enhancement of the Tb–Gd–ATP–phen system is considered to originate from intramolecular and intermolecular energy transfers, and the energy-insulating sheath effect of Gd–ATP–phen complex. In addition, a new energy transfer pathway in Tb–ATP–phen system is proposed. As a mediator, phen can transfer the energy absorbed by ATP to Tb3+ through the stacking action between aromatic ring of phen and purine ring of ATP. The proposed method has been used to determine trace amount of ATP. The detection limit is 5.4 × 10−9 mol/l, which is about 40 times lower than that of the Tb–ATP–phen system. The proposed method is one of the most sensitive fluoremetries of ATP.