The new fluorescence enhancement system Tb–N-(2-pyridinyl) ketoacetamide–Et3N–Zn and its application

A sensitive fluorescence enhancement system was developed for the determination of terbium. The fluorescence intensity of the Tb–N-(2-pyridinyl) ketoacetamide (PKAA) system was greatly enhanced by the addition of triethylamine (Et3N) and zinc nitrate in the methanol solution. The excitation and emission wavelengths were 329 and 546 nm, respectively. Under optimal conditions, the fluorescence intensities varied linearly with the concentration of Tb3+ in the range of 7.5 × 10−8–8.2 × 10−6 M with a detection limit of 6.4 × 10−8 M. The interferences of some rare earth ions were described. This method was applied to the determination of trace amounts of terbium (III) in a synthetic rare earth oxide and a high purity Y2O3 matrix. The mechanism of fluorescence enhancement was also studied.