Synthesis of a New Fluorescence Reagent-1-(8-Quinoline)-3-(3,5-Dibromo-pyridine)-Triazene and Its Analytical Application

By connecting the triazene structure with the heterocyclic fluorescent reagents of quinoline and pyridine, a new fluorescence reagent of 1-(8-quinoline)-3-(3,5-dibromo-pyridine)-triazene (QBPyT) was synthesized and identified by elemental analysis, IRS and NMR. Strong fluorescence at the wavelengths of 248 nm (λex) and 496 nm (λem) was emitted by this reagent in a borate buffer medium of pH 9.5, and an enhancement of fluorescence was observed in the presence of Pb(Ⅱ) ion due to the formation of a coordination complex between Pb(Ⅱ) and QBPyT. Linear relationship between the magnitude of increase in fluorescence intensity and concentration of Pb(Ⅱ) was obtained in the range of 5.0×10-7-1.2×10-5mol·L with detection limit (3S/N) of 9.5×10-8mol·L. The proposed method was used in the analysis of water samples, giving RSD′s (n=5) less than 3.5%, and using these samples as matrixes, recovery was tested, the values of recovery found were ranged from 92.6% to 94.0%.