Spectrophotometric investigation on the interaction of acridine orange with methylene blue, phenosafranine, and disulphine blue in aqueous medium

Abstract

The results of dye–dye interactions for the pairs, acridine orange – methylene blue, acridine orange – phenosafranine, and acridine orange – disulphine blue have been presented. It has been found that at comparable concentrations the interaction is rather weak, and the formation of mixed entities is only possible at relatively high proportions of one of the components. However, the evidence of mixed dimers in the form of a new absorption band is lacking. Phenosafranine remarkably promotes dimerization of acridine orange. An experimental demonstration of the dimer spectra of acridine orange has thus been possible. The interaction of the anionic dye disulphine blue with cationic acridine orange has been observed to be the weakest of all the pairs, indicating the vital role of the structural parity for interaction. At comparable low concentrations, none of the dye-pairs studied have revealed compound metachromasy in the presence of a polyelectrolyte, suggesting unfavorable mixed dye aggregation under ordinary conditions.