Room-temperature phosphorescent palladium-porphine probe for DNA determination.

Room-temperature phosphorescence (RTP) enhancement of a palladium-porphine complex by DNA was studied. Studies involving calf thymus DNA and calf liver RNA revealed that the Pd-porphine complex bound to double-stranded DNA displayed intense RTP, while a very weak RTP emission was observed in the presence of equal molar concentrations of RNA. This fact founded a basis for selective determination of DNA in the presence of RNA. Maximum phosphorescence was observed at pH 7, with maximum excitation and emission wavelengths at 435 and 680 nm, respectively. Under optimal experimental conditions, the calibration graphs were linear up to 6 × 10(-)(5) μM DNA. The detection limit was 5 × 10(-)(8) μM and the relative standard deviation (10 replicates) ±2.6% in the linear range. DNA extracted from human colon tissues could be successfully determined.