DETERMINATION OF TRACE EUROPIUM BASED ON NEW FLUOROMETRIC SYSTEM OF EUROPIUM(III) WITH THENOYLTRIFLUOROACETONE AND N'-DINAPHTHYL-N,N'-DIPHENYL-3,6-DIOXAOCTANEDIAMIDE

In the present paper, N'-dinaphthyl-N,N'-diphenyl-3,6-dioxaoctanediami de acts as a specific reagent for enhancing the fluorescence intensity of Eu(III) complex with thenoyl trifluoroacetone (TTA), the spectrofl uorimetric determination of trace amounts of Eu(III) based on the abov e system was carried out and its luminescence mechanism was studied. T he excitation and emission wavelengths are 343.6 and 613.3 nm, respect ively. The fluorescence intensities vary linearly with the concentrati on of europium(III) in the range 3.647 x 10(-3)-3.039 mu g ml(-1) for the original fluorescence with a detection limit down to 2.279 x 10(-4 ) mu g ml(-1) and the standard deviation is 0.063 mu g ml(-1) for 10 t imes measurements? and in the range 7.598 x 10(-4)-0.0243 mu g ml(-1) (SD = 0.035 for 15 times measurements), 0.06078-0.6100 mu g ml(-1) (SD = 0.52 for 10 times measurements) for the first derivative fluorescen ce signal with a detection limit down to 8.566 x 10(-5) mu g ml(-1). T he interferences of other rare earths and some of inorganic ions are d escribed. This method is a direct, rapid, selective and sensitive anal ytical method for the determination of trivalent europium in rare eart h ore samples and high purity of rare earth oxides. (C) 1998 Elsevier Science B.V. All rights reserved.