Study on the new fluorescence enhancement system of Tb -N-(2 - pyridinyl) ketoacetamide-Et3N-Zn and its application.

A sensitive fluorescence enhancement system was developed for the determination of zinc (II). The fluorescence intensity of the Tb- N- (2 - Pyridinyl) ketoacetamide (PKA) system was greatly enhanced by the addition of triethylamine (Et(3)N) and zinc nitrate in the methanol solution. The excitation and emission wavelengths were 329 nm and 546 nm, respectively. Under optimal conditions, the fluorescence intensities varied linearly with the concentration of Zn(2+) in the range of 8.0 x 10(-7)-5.0 x 10(-6) M with a detection limit of 9.9 x 10(-8) M. The interferences of some substances were described. This method was applied to the determination of amounts of Zn(2+) in soybean, rice, and wheat, respectively. The results showed that the proposed procedure is a high selective, simple, and rapid method to the determination of Zn(2+) ion. The mechanism of fluorescence enhancement was also studied.