Determination of nucleic acids using phosphin 3R as a fluorescence probe

A novel fluorimetric method has been developed for rapid determination of DNA and RNA with phosphin 3R (PR) as a fluorescence probe, based on the fluorescence quenching of PR in the presence of DNA or RNA. Maximum fluorescence quenching is observed in the pH range 7.0-8.4, with maximum excitation and emission wavelength at 468 and 505nm, respectively. Under optimal conditions, the calibration graphs are linear up to 2.0μg/ml for both calf thymus DNA (CT DNA) and salmon DNA (SM DNA), and up to 1.6μg/ml for yeast RNA, respectively. The corresponding detection limits are 5.0ng/ml for CT DNA, 6.0ng/ml for SM DNA and 13.0ng/ml for yeast RNA. CT DNA could be determined in the presence of 20% (w/w) yeast RNA, and the relative standard deviation of six replicate measurements is 1.00% for a solution containing 400ng/ml of CT DNA. Three real samples were determined with satisfactory results. The interaction mechanism for the binding of PR to DNA is also studied; the results of absorption spectra and thermal denaturation experiments suggested the interaction between PR and DNA to be intercalative in nature. Copyright (C) 1999 Elsevier Science B.V.