Study on sensitised luminescence of rare earths by fluorescence enhancement of the europium-gadolinium-diphacinone-ammonia complex system and its application

Abstract

A study of the enhancement effect on the fluorescence intensity of the Eu³⁺-diphacinone(DPN)-ammonia system by La³⁺, Gd³⁺ and Y³⁺, has been carried out in a colloid-type suspension. Gadolinium caused the largest enhancement of the fluorescence intensity. In the presence of this element the fluorescence of the Eu-DPN-NH₃ system was enhanced by a factor of about 100 at a pH of between 8.5 and 9.5. Excitation and emission wavelengths were 330 and 612 nm, respectively. Fluorescence intensity was a linear function of the concentration of europium in the range 8.0 × 10^–9–1.0 × 10^–11 M. The detection limit was 6.0 × 10^–14 M. The standard additions method was used for the determination of europium in rare earth oxides and gave satisfactory results.