[Study of interaction of ciprofloxacin probe and calf thymus DNA using fluorescence spectrometry]

The interaction of ciprofloxacin and calf thymus DNA (ctDNA) was studied using UV spectrometry and fluorescence spectrometry. Ciprofloxacin 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 X 104 mol(-1) x L(25 degrees C). Based on the fluorescence quenching, a novel method for sensitive determination of calf thymus ctDNA concentration ranging from 80 nmol x L(-1) to 45 micromol x L(-1) was developed. The relative standard deviation for eleven detections of 25 micromol x L(-1) ctDNA was 4. 2%.