Enhanced fluorescence of 3-tryptimino-1-phenyl-butan-1-one–Tb with 1,10-phenanthroline ternary system, and its analytical application

A new and efficient luminescence enhancement system of Eu-N-(3,5-dibromosalicylidene)-2-aminopyridine-1,10-phenanthroline and its application in the determination of trace amounts of europium

A sensitive luminescence enhancement system has been developed for the determination of trace amounts of trivalent europium. The luminescence intensity of europium complex with N-(3,5-dibromosalicylidene)-2-aminopyridine (HL) was greatly enhanced after the addition of 1,10-phenanthroline (Phen) in acetonitrile solution. The excitation and emission wavelengths were 274 and 617 nm respectively. Under optimal conditions, the luminescence intensities varied linearly with Eu(3+) concentration in the range of 4.0 × 10(-6)∼2.4 × 10(-5) mol L(-1) with a detection limit of 4.3 × 10(-10) mol L(-1). This method was successfully applied to determine the trace amounts of Eu(3+) in a high purity Gd(2)O(3) matrix and in a mixed lanthanide sample. Energy transfer mechanism and luminescence enhancement of HL-Phen-Eu ternary system were studied. The results indicate that both HL and Phen are good sensitizers for the luminescence of Eu(3+) ions, as energy gap between the lowest triplet level of HL/Phen and the resonant level of Eu(3+) ((5)D(1)) exists around the optimal value (3000 ± 500 cm(-1)). The interference by some other lanthanide ions and common ions were also studied.