Some photometric and fluorimetric characteristics of acridine orange and of its complexes with glycosaminoglycans: proposed method for their spectrophotofluorimetric evaluation. I. Spectrophotometric study

In spite of the wide use of AO as basic fluorochrome in cytology, histology and histochemistry, however there still persist some queries on the meaning of fluorescence due to the encounter of a such molecule with anionic polymers. From the spectrophotometric data exposed in the present paper, AO is stressed as a metachromatic colouring and therefore, as such, may be used in histochemical investigation. Besides, because of the reliable identificaton of the single types of GAG, screening may be performed at different pH, since metachromasia appears at different pH for the three different types of GAG. A useful counterproof may be performed by means of selective elutions of the AO/GAG complexes, being solutions with increasing ionic power.