and the plates were placed at room temperature for 20min. The sample fluorescence was then scanned on a microplate reader (Perkin-Elmer, ARVO MX1420) with 530 nm (excitation) and 590 nm (emission) filters (First scan). 7.5 μL of 100 μg mL−1 RNase solution was added to each well. The microplate was settled at room temperature for 15min and the sample fluorescence was then scanned again (Second scan). The RNA concentrations (μg mL−1) were calculated as the differences between first (DNA + RNA) and second (DNA) scans, and the standard curve of RNA versus the fluorescence established from the first scan of the same plate. DNA concentrations (μg mL−1) were computed from the second scan and the standard curve of DNA versus fluorescence established at the second scan (RNase treated) of the same plate.