Acridine orange has been recommended as a fluorochrome to differentiate between DNA (green fluorescence) and RNA (red fluorescence). It also makes a good fluorescent Schiff reagent.
R. D. Lillie.
Conn's Biological Stains
Williams & Wilkins, Baltimore, MD., U.S.A.
Edward Gurr, (1971)
Synthetic dyes in biology, medicine and chemistry
Academic Press, London, England.
Aldrich chemical catalogue, 1992
Aldrich Chemical Company, Milwaukee, WI, USA.