铽-环丙沙星与罗丹明B间稀土敏化荧光能量转移机理研究

Study on Mechanism of Lanthanide Sensitized Fluorescence Energy Transfer between Terbium(Ⅲ)-Ciprofloxacin and Rhodamine B

利用荧光光谱法及紫外光谱法研究发现pH6.2醋酸-醋酸钠(HAc-NaAc)水溶液中铽与环丙沙星形成络合物使铽在490,545,590nm处出现Tb3+的特征发射峰即荧光被强烈的敏化增强,且在545nm处的荧光强度最大,铽离子的锐线发射光谱的特征最强峰545nm与罗丹明B的最大吸收峰波长552nm十分接近,能够发生能量转移反应。因此,随着碱性染料罗丹明B的加入铽-环丙沙星的特征荧光呈现有规律降低,表明罗丹明B对铽-环丙沙星荧光有猝灭作用,研究结果表明其猝灭类型主要为静态猝灭。又根据Frster理论,测得了罗丹明B对铽-环丙沙星的能量转移效率,相互结合距离等参数。从而进一步证明了该反应是单一静态猝灭过程,阐述了其荧光猝灭机理是通过能量转移产生的。

A complex composed of ciprofloxacin and terbium （Tb^3＋） in the solution of acetic acid-sodium acetate buffer （pH 6.2） was studied by fluorescence spectroscopy and ultra-violet absorption spectroscopy. The emission peak of Tb3＋ appeared at 490, 545, 590 nm, （the sensitized fluorescence was enforced mightily）and the intensity of 545 nm emission peak was increased obviously. In its acute emission spectrum, the strongest emission peak of Tb^3＋ was at 545 nm, which was close to the wavelength of the biggest absorption peak of RB, 552 nm. Therefore, as the basic dye rhodamine B（RB） was added, the fluorescence intensity of 545 nm emission peak decreased regularly, indicating that there was a great quenching process. The result showed that the course was statistic. Based on the mechanism of the Frster energy transfer, the efficiency of energy transfer and the distance between the acceptor RB and the complex were found. Thereby, it was indicated that the course of action was single static quenching and the mechanism of quenching was based on energy transfer.