Xanthene dyes for reducing acoustic cavitation threshold in aqueous solution

The effect of xanthene dyes on the acoustic cavitation threshold in an aqueous solution was investigated in a progressive wave field. Among fluorescein and its halogenated derivatives, rose bengal (RB), phloxin B (PB), erythrosin B (EB) and tetrachlorofluorescein (TCF) were found to reduce the intensity threshold for inducing cavitation which accompanies subharmonic emission. In phosphate buffer saline, subharmonic emission in the presence of RB or PB was observed at an acoustic intensity more than five times lower than the acoustic intensity in their absence. When iodide ions were also present in the solution, their oxidation proceeded with the subharmonic emission. This indicates that xanthene dyes reduced the threshold for sonochemically active cavitation. The ability of xanthene dyes to reduce the cavitation threshold did not significantly correlate with their surface tension and viscosity, but strongly correlated with their ability to stabilize foams.