中文摘要：

使用紫外和荧光光谱法研究了环丙氟沙星（CIF）和小牛胸腺DNA（ctDNA）之间的相互作用。在pH7．0磷酸盐缓冲液中，CIF在270nm激发和在420nm处有很强的荧光发射。它们间的沟槽作用导致小牛胸腺ctDNA对CIF的荧光存在着很强的猝灭作用，猝灭常数为2．64×10^4mol^-1L（25℃）。利用ctDNA对CIF的荧光猝灭作用建立了核酸测定的新方法，线性范围为80nmol·L^-1～45μmol·L^-1，对25μmol·L^-1叫ctDNA的相对标准偏差为4．2％。

英文摘要：

The interaction of ciprofloxacin and calf thymus DNA （ctDNA） was studied using UV spectrometry and fluorescence spectrometry. Ciprofloxaein exhibited a fluorescence excitation at 270 nm and a fluorescence emission at 420 nm in pH 7. 0 phosphate buffer solutions due to the groove binding of ciprofloxacin on calf thymus ctDNA. The binding constant was 2.64 × 10^4 mol · L^-1（25 ℃ ）. Based on the fluorescence quenching, a novel method for sensitive determination of calf thymus ctDNA concentration ranging from 80 nmol · L^-1 to 45 μmol·L^-1 was developed. The relative standard deviation for eleven detections of 25 μmol·L^-1 ctDNA was 4. 2%.