Abstract: Through combinination of 8-aminoquinoline with pydine through triazene group, a new fluorescent reagent 1-(8-quinoline)-3-(pyridyl)-triazene(QPyT) was synthesized. The product was confirmed by means of elemental analysis, ¹H NMR and infrared spectra. Its excitation and emission wavelengths were 216 nm and 343 nm in a basic medium, respectively. This new reagent reacted with Pb(Ⅱ) in a slightly basic medium to form a 1∶1 complex, by which lead ion caused the fluorescence quenching of the new fluorescent reagent. The possible response mechanism of QPyT to Pb(Ⅱ) was discussed. The reaction showed a high selectivity and a high sensitivity for Pb(Ⅱ). The new fluorescent reagent was used to determined trace Pb(Ⅱ). The optimum analytical conditions for Pb(Ⅱ) assay were established. Under these conditions, the linear range of Pb(Ⅱ) was from 1.6×10^-7 to 1.2×10^-5 mol/L, with a detection limit 9.0×10^-8 mol/L. The method is selective, sensitive and simple. It was used for the determination of trace Pb(Ⅱ) in water sample with satisfactory results.

Key words: 1-(8-Quinoline)-3-(pyridyl)-triazene, Detection of lead, Fluorescence quenching