Abstract: In pH=5.4 Britton-Robinson(BR) buffer solution, fenaminosulf(FM) reacted with acriflavine(AF) to form an ion associated complex, which resulted in the quench of the fluorescences of acriflavine. The maximum excitation wavelength(λex) and emission wavelength(λem) was located at 451 nm and 508 nm. The quenching value(ΔF) was linear to the concentration of FM in the range of 0.16~5.0 mg/L with the detection of limit(3σ) of 0.048 mg/L. Therefore, a simple, rapid, highly sensitive and selective method for the determination of FM by fluorescence quenching had been established. The proposed method had been used to determine FM in fenaminosulf pesticide and soil residue with satisfactory results. In addition, the fluorescence characters of the reaction system and the mechanism of fluorescence quenching were also discussed by AM1 calculations.

Key words: Fenaminosulf, Acriflavine, Fluorescence quenching