Flow-injection chemiluminescence study of Ce(IV)-Na2SO3-Tb(III)-fluoquinolone antibiotic system with DNA

A novel flow injection chemiluminescence (CL) system is developed to determine DNA. According to the fact that DNA linearly quenches the CL intensity of Ce(IV)-Na2SO3-Tb(III)-fluoquinolone antibiotic (FLUQ) system, DNA concentration is determined. The calibration graphs are linear in the range of 0.04-10 mug/ml (for both natural and denatured DNA), and the 3sigma limits of detection are 7.8 ng/ml (natural DNA) and 9.5 ng/ml (denatured DNA). According to fluorescence spectrum and CL spectrum, and through studying the reaction of Ce(IV)-Na2SO3-Tb(III)FLUQ with nucleotides and bases, we conclude that DNA counteracts the energy transfer from FLUQ to Tb(III), and this function is related to both bases and phosphate groups in DNA. (C) 2003 Elsevier B.V. All rights reserved.