The Fluorescent Reaction Between Quinaldine Red and Nucleic Acids and its Application to Fluorescent Assay of DNA and RNA

 The reaction between quinaldine red (QR) and nucleic acids was studied. The free QR alone has no fluorescence in solution. However, it becomes fluorescent after binding to nucleic acids, giving maximum emission at 607 nm with maximum excitation at 557 nm. Maximum fluorescence intensity is produced in the pH range of 3.2–3.6. Based on the fluorescent reactions, a novel fluorometric method was developed for rapid determination of nucleic acids using QR as the fluorescent probe. Under optimal conditions, the calibration graphs were linear in the range of 0–30.0 µg mL−1 for CT DNA and 0–20.0 µg mL−1 for yeast RNA. The limits of detection were 38 ng mL−1 for CT DNA and 142 ng mL−1 for yeast RNA. Four synthetic samples were determined with satisfaction.