Pd(II)对氟喹诺酮类抗生素的荧光猝灭作用及其分析应用

在弱酸性至近中性介质中， 培氟沙星（PEF）、左氧氟沙星（LEV）、洛美沙星（LOM）和氟罗沙星（FLE）等4种氟喹诺酮类抗生素（FLQs）具有类似的激发光谱和荧光光谱， 当它们与Pd（II）反应形成配合物时， 均能导致荧光的猝灭. 本文以Pd（II）-PEF体系为例， 研究了吸收光谱、荧光光谱的变化， 并用量子化学的密度泛函方法（B3LYP）对反应进行了全优化计算研究. 结果表明， Pd（II）与两分子的PEF结合形成具有2个6元环的平面四边形螯合物， 这类荧光猝灭是一种静态猝灭过程. 当用上述4种氟喹诺酮作荧光探针时， 对Pd的测定具有较高的灵敏度， 其检出限在1.74~3.42 ng/mL. 该方法简便、快速， 具有良好的准确度、精密度， 以及较好的选择性， 可用于某些环境水样中Pd（II）的测定.

The fluorescence quenching of fluoroquinolones by palladium(II) and its analytical application

In a weakly acidic or neutral medium, fluoroquinolones (FLQs) such as pefloxacin (PEF), levofloxacin (LEV), lomefloxacin (LOM) and fleroxacin (FLE), have similar fluorescence spectral characteristics. Their fluorescence intensities could be significantly quenched by palladium. In this work, taking Pd(II)-PEF system as an example, the absorption and fluorescence spectral changes were investigated. In addition, the density functional theory (DFT) methods (B3LYP) was performed to optimize those compounds. A Pd (II) molecule bond two PEF molecules to form a square planar chelate with two six-membered rings, and the quenching effect of Pd(II) on PEF fluorescence is a single static quenching event. The detection limits were in the range of 1.74-3.42 ng/mL using the above four FLQs. Most of metal ions and inorganic anions have no interference. The method was applied to the determination of Pd(II) in environmental water.