Brilliant cresyl blue as a new red region fluorescent probe for determination of nucleic acids

A fluorescence quenching method was developed for determination of microamo unts of nucleic acids by using brilliant cresyl blue (BCB) as a new red reg ion fluorescent probe. In aqueous hexylmethylene tetramine solution, BCB sh owed maximum excitation and emission wavelengths at 626 and 670 nm, respect ively, and the fluorescence of BCB could be greatly quenched by DNA (or RNA ). Under optimal conditions, the calibration graphs are linear over the ran ge of 0.02-0.80 mu g/ml for SM DNA and 0.25-1.5 mu g/ml for yeast RNA. The corresponding detection limits are 7 ng/ml for SM DNA and 25 ng/ml for yeas t RNA, respectively. SM DNA can be determinated in the presence of 40% (w/w ) RNA, and the relative standard deviation of six measurements is 2.5% for 500 ng/ml SM DNA. The result of the determination of golden staphylococcus DNA by this method was satisfactory. (C) 2000 Elsevier Science B.V. All rig hts reserved.